Production of 66000 ton/year of Formaldehyde from Methanol using Silver catalyst. Final year project - BSC Chemical Engineering 2014-2018

PRODUCTION OF 66000 TPY OF
FORMALDEHYDE FROM METHANOL USING
SILVER CATALYST
Session 2014-2018
Supervisors
Engr. Kashif Iqbal
Engr. Nazar Mehmood
Group Members
Attique Ahmed Baber UW-14-CH.E-BSC-010
Zain Ali UW-14-CH.E-BSC-020
Muhammad Zeeshan UW-14-CH.E-BSC-025
Waqas Anjum UW-14-CH.E-BSC-026
Department of Chemical Engineering
Wah Engineering College
University of Wah, Wah Cantt

PRODUCTION OF 66000 TPY OF
FORMALDEHYDE FROM METHANOL USING
SILVER CATALYST
This report is submitted to the Department of Chemical Engineering,
Wah Engineering College, University of Wah for the partial fulfilments of the
requirement for the
Bachelor of Science
In
Chemical Engineering
Internal Examiner:
Sign:
Name:
External Examiner:
Sign:
Name:
Department of Chemical Engineering
Wah Engineering College
University of Wah, Wah Cantt
2014-2018

Dedicated To
Our
Beloved Parents,
Respected Teachers,
&
All Those Who Devoted Their Yesterday for Our
Bright Today

Acknowledgement
All praises to ALMIGHTY ALLAH, who provided us with the strength to accomplish
the final year project. All respects are for His HOLY PROPHET (PBUH), Whose teachings are
true source of knowledge and guidance for whole mankind.
Before anybody else we thank our Parents who have always been a source of moral
support and driving force behind whatever we do. We are grateful to the Head of Department
Prof. Dr. A.K. Salariya and our faculty members for providing facilities and guidance. We are
indebted to our project supervisors Mr. Kashif Iqbal and Mr. Nazar Mehmood and project
coordinator Ms. Rabia Sabir for their worthy discussions, encouragement, inspiring guidance,
remarkable suggestions, keen interest, constructive criticism & friendly discussions which
enabled us to complete this report. They spared a lot of precious time in advising and helping us
in writing this report. Without their painstaking tuition, kind patronization, sincere coaching and
continuous consultation, we would not have been able to complete this arduous task successfully.

Abstract
Formaldehyde, the target product of the present work, is an organic compound representing the
most elementary configuration of the aldehydes. It behaves as a synthesis baseline for many other
chemical compounds, including phenol formaldehyde, urea formaldehyde, melamine resin,
Paints, and Glues. It is also used in medical field i.e. as a disinfectant and preservation of cell and
tissues. The aim of the present work is to reach 98% conversion of methanol using Silver
Catalyst. Detailed calculations were performed in this report for all equipment in the plant
including all expenses of the plant erection, taking into account the required process conditions to
achieve a production capacity of 66000 ton/year of formaldehyde (as formalin).

Contents
Chapter No.1, Introduction ................................................................................................……..1
1.1 Introduction ........................................................................................................................... 2
1.2 History:.................................................................................................................................. 2
1.3 Properties:.............................................................................................................................. 3
1.4 Reactions of the Product:....................................................................................................... 4
1.5 Industrial Applications: ......................................................................................................... 4
1.6 Handling: ............................................................................................................................... 5
1.7 Disposal:................................................................................................................................ 7
1.8 Shipping:................................................................................................................................ 7
1.9 Motivation for the Project: .................................................................................................... 7
1.10 Feasibility: ........................................................................................................................... 8
Chapter No.2, Manufacturing Process ..............................................................................……..9
2.1 Production Methods: ........................................................................................................... 10
2.2 Silver Process ...................................................................................................................... 10
2.3 Metal Oxide Process:........................................................................................................... 11
2.4 Comparing the Silver and Oxide Processes:........................................................................ 12
2.5 Process Selection:................................................................................................................ 13
2.6 Capacity Selection and Its Justification:.............................................................................. 14
2.7 Silver Process Description and Flow Sheet:........................................................................ 14
2.8 Metal Oxide Catalyst Process:............................................................................................. 18
2.9 Process Flow Diagram Of Silver Process:........................................................................... 21
Chapter No. 3, Material Balance........................................................................................……23
3.1 Main Reactions:................................................................................................................... 24
3.2 Capacity:.............................................................................................................................. 24
3.3 Material Balance at Vaporizer (V-100) & Mixing Point:.................................................... 24
3.4 Material Balance at Reactor (R-100):.................................................................................. 25
3.4.1 For Reaction 1: ............................................................................................................. 25
3.4.2 For Reaction 2: ............................................................................................................. 26
3.5 Material Balance at Absorber (A-100):............................................................................... 28
3.6 Material Balance at Distillation Tower (D-100): ................................................................ 29
Chapter No. 4, Energy Balance..........................................................................................……31
4.1 Energy Balance on Vaporizer (V-100):............................................................................... 32
4.2 Energy Balance at Reactor (R-100):.................................................................................... 33

4.3 Energy Balance at Absorber (A-100):................................................................................. 36
4.4 Energy balance on Distillation Unit (D-100): ..................................................................... 38
4.5 Energy Balance at Exchanger (E-100): ............................................................................... 40
Chapter No. 5, Equipment Selection and Design..............................................................……41
5.1 Design of Vaporizer (V-100):.............................................................................................. 42
5.2 Design of Reactor (R-100): ................................................................................................. 55
5.3 Design of Absorber (A-100):............................................................................................... 64
5.4 Design of Distillation Column (D-100):.............................................................................. 77
5.5 Design of Heat Exchanger (E-100): .................................................................................... 92
Chapter No. 6, Mechanical Design.....................................................................................…..101
6.1 Max Allowable Pressure:................................................................................................... 102
6.2 Max Allowable Temperature:............................................................................................ 102
6.3 Wall Thickness:................................................................................................................. 102
6.4 Torispherical Head: ........................................................................................................... 103
6.5 Vessel Supports: ................................................................................................................ 103
6.6 Circumferential Stress: ...................................................................................................... 103
6.7 Longitudinal Stress:........................................................................................................... 104
6.8 Weight Load:..................................................................................................................... 104
6.9 Wind Load:........................................................................................................................ 104
6.10 Radial Stress:................................................................................................................... 104
6.11 Bending Moment:............................................................................................................ 105
6.12 Dead Weight Stress: ........................................................................................................ 105
6.13 Bending Stress:................................................................................................................ 105
6.14 Allowable Stress Intensity:.............................................................................................. 105
Chapter No.7, Pump Sizing.................................................................................................…..108
7.1 Pumps (P-100):.................................................................................................................. 109
Chapter No. 8, Cost Estimation..........................................................................................…..112
8.1 Equipment’s Cost: ............................................................................................................. 113
8.2 Direct Cost......................................................................................................................... 119
8.3 Indirect Cost: ..................................................................................................................... 119
8.4 Fixed Capital Investment (FCI):........................................................................................ 119
8.5 Working Capital Investment (WCI):................................................................................. 120
8.6 Total Capital Investment: .................................................................................................. 120
8.7 Raw Materials:................................................................................................................... 120

8.8 Operating Labor:................................................................................................................ 121
8.9 Total Production Cost:....................................................................................................... 122
8.10 General Expenses: ........................................................................................................... 123
8.11 Depreciation: ................................................................................................................... 123
8.12 Gross Earning:................................................................................................................. 123
8.13 Rate of Return (ROR):..................................................................................................... 124
8.14 Payback Period:............................................................................................................... 124
Chapter No. 9, Instrumentation and Control ...................................................................…..125
9.1 Introduction ....................................................................................................................... 126
9.2 Control Mechanism ........................................................................................................... 126
9.3 Process Control.................................................................................................................. 126
9.4 Objectives of Instrumentation and Control System........................................................... 126
9.5 Components of the Control System................................................................................... 127
9.6 Types of Control................................................................................................................ 127
9.7 Feedback Control............................................................................................................... 127
9.7 Feed Forward Control........................................................................................................ 128
9.8 Process Variable ................................................................................................................ 128
9.9 Temperature Measurement and Control............................................................................ 129
9.10 Pressure Measurement and Control................................................................................. 129
9.11 Flow Measurement and Control ...................................................................................... 129
9.12 Process Control System Hardware .................................................................................. 130
9.13 Valve Selection................................................................................................................ 131
Chapter No.10, Hazop Study..............................................................................................…..134
10.1 Background: .................................................................................................................... 135
10.2 Introduction: .................................................................................................................... 135
10.3 Success or Failure:........................................................................................................... 135
10.4 Hazop Characteristics:..................................................................................................... 136
10.5 Advantages: ..................................................................................................................... 136
10.6 Disadvantages:................................................................................................................. 136
10.7 Effectiveness:................................................................................................................... 137
10.8 Key Elements: ................................................................................................................. 137
10.9 Hazop Study on Reactor R-100:...................................................................................... 138
Chapter No. 11, Environmental Impact Assessment .......................................................…..140
11.1 Environmental Impact Assessment: ................................................................................ 141

11.1.1 Overview: ................................................................................................................. 141
11.1.2 Objectives:................................................................................................................ 141
11.1.3 Advantages: .............................................................................................................. 141
11.2 Methanol:......................................................................................................................... 141
11.2.1 Hazard: ..................................................................................................................... 142
11.2.2 Protective measures.................................................................................................. 142
11.2.3 Spills and emergencies ............................................................................................. 143
11.3 Formaldehyde:................................................................................................................. 143
11.3.1 Hazards:.................................................................................................................... 143
11.3.2 Protective measures.................................................................................................. 144
11.3.3 Spills and emergencies: ............................................................................................ 144
References: ...........................................................................................................................…..145
Appendix ..............................................................................................................................…..147

List OF Figure:
Figure 1.1: Formaldehyde Formula................................................................................................ 2
Figure 1.2: World Consumption Data ............................................................................................ 8
Figure 2.1: Flow Sheet of Formaldehyde using Silver Catalyst................................................... 17
Figure 2.2: Flow Sheet of Formaldehyde Using Metal Oxide Catalyst ....................................... 20
Figure 2.3: Process Flow Diagram of Formaldehyde Using Silver Catalyst ............................... 21
Figure 3.1: Material Balance V-100............................................................................................. 24
Figure 3.2: Material Balance at R-100 ......................................................................................... 25
Figure 3.3: Material Balance at A-100......................................................................................... 28
Figure 3.4: Material Balance at D-100......................................................................................... 29
Figure 4.1: Energy Balance V-100............................................................................................... 32
Figure 4.2: Energy Balance at R-100 ........................................................................................... 33
Figure 4.3: Energy Balance at A-100........................................................................................... 36
Figure 4.4: Energy Balance at D-100........................................................................................... 38
Figure 4.5: Energy Balance at E-100 ........................................................................................... 40
Figure 5.1: Vaporizer V-100 ........................................................................................................ 43
Figure 5.2: Reactor (R-100) ......................................................................................................... 56
Figure 5.3: Levenspiel Plot between Conversion and Inverse of Rate Law ................................ 59
Figure 5.4: Absorber A-100 ......................................................................................................... 66
Figure 5.5: Distillation Tower D-100........................................................................................... 78
Figure 5.6: Heat Exchanger E-100............................................................................................... 94
Figure 9.1: Diaphragm valve...................................................................................................... 132
Figure 9.2: Flanged Valve.......................................................................................................... 132
Figure 9.3: Non-return valve...................................................................................................... 132
Figure 9.4: Gate valve ................................................................................................................ 133
Figure 9.5: Instrumentation and Control on Distillation Column .............................................. 133

List of Tables:
Table 1.1: Physical & Thermal Properties...................................................................................... 3
Table 2.1: Comparison of Processes............................................................................................. 13
Table 2.2: Capacity Selection...................................................................................................... 14
Table 2.3: Components and flow rates ......................................................................................... 22
Table 3.1: Material Balance at V-100........................................................................................... 25
Table 3.2: Material Balance R-100............................................................................................... 26
Table 3.3: Material Balance R-100............................................................................................... 27
Table 3.4: Material Balance at A-100........................................................................................... 29
Table 3.5: Material Balance at D-100........................................................................................... 30
Table 4.1: Energy Balance at Vaporizer V-100............................................................................ 32
Table 4.2: Energy Balance at R-100............................................................................................. 34
Table 4.3: Energy Balance at Inlet A-100 .................................................................................... 36
Table 4.4 Energy Balance at Outlet of A-100............................................................................... 37
Table 4.5: Energy Balance at Reboiler:........................................................................................ 38
Table 4.6: Energy Balance at Condenser:..................................................................................... 39
Table 5.1: Components Table....................................................................................................... 58
Table 5.2: Relation between Conversion and Rate Law .............................................................. 58
Table 5.3: Choice of Distillation .................................................................................................. 77
Table 5.4: Composition of Components....................................................................................... 78
Table 5.5: Antoine Coefficients.................................................................................................... 79
Table 5.6: Partial Pressure Pi........................................................................................................ 79
Table 5.7: Partial Pressure of Components .................................................................................. 79
Table 5.8: Bubble Point Calculation for Feed .............................................................................. 80
Table 5.9: Dew Point Calculation of Top..................................................................................... 81
Table 5.10: Bubble Point Calculation of Bottom ......................................................................... 81
Table 5.11: Underwood Equation................................................................................................. 82
Table 5.12: Heat Exchanger Type ................................................................................................ 92
Table 8.1: Total Equipment Cost ($).......................................................................................... 119
Table 8.2: Fixed Cost.................................................................................................................. 122
Table 8.3: General Expenses ...................................................................................................... 123
Table 9.1: Various types of measuring instruments for Temperature, Pressure......................... 130
Table 9.2: Various types of measuring instruments flow Rate and level ................................... 130

Table 10.1: Guide Words............................................................................................................ 137
Table 10.2: Hazop Study on Reactor (R-100) ............................................................................ 138

Chapter No.1 Introduction
1
Chapter No.1
1 Introduction

2
1.1 Introduction
Formaldehyde is widely abundant in nature and the anthropogenic environments owing to several
natural and non-natural decomposition pathways of both biological and non-natural organic
matter. Formaldehyde, also called Methanal (formulated HCHO), an organic compound, the
modest of the aldehydes, used in huge amounts in a diversity of chemical manufacturing
processes. It is formed principally by the vapor-phase oxidation of methanol and is normally sold
as formalin. The chemical compound formaldehyde (also known as methanal) is a gas with a
pungent smell. It is the modest aldehyde. Its chemical formula is H2CO. Formaldehyde was first
produced by the Russian chemist Aleksandr Butlerov in 1859 but was finally identified by
August Wilhelm von Hofmann in 1868.
Formaldehyde readily results from the incomplete burning of carbon-containing materials. It may
be found in the smoke from forestry fires, in vehicle exhaust, and in tobacco smoke. In
the atmosphere, formaldehyde is formed by the action of sunlight and oxygen on
atmospheric methane and further hydrocarbons. Small amounts of formaldehyde are made as
a metabolic byproduct in maximum organisms, including humans.[1]
Figure 1.1: Formaldehyde Formula
Formaldehyde can be listed on a product tag by other names, such as: Formalin, Formic
aldehyde, Methanediol, Methanal, Methyl aldehyde, Methylene glycol, Methylene oxide.
1.2 History:
Formaldehyde is a naturally arising organic compound composed of carbon, hydrogen and
oxygen. It has a modest chemical structure of CH2O. Formaldehyde was first defined in 1859 by
Alexander Mikhailovich Butlerov when he tried to make methylene glycol. However,
formaldehyde wasn’t finally identified until 1868, when August Wilhelm von Hofmann, a
professor of chemistry and director of the laboratory of the University of Berlin, set out to clearly
create both the structure and identity of formaldehyde. The method that Hoffman used to identify
formaldehyde placed the foundation for the modern formaldehyde manufacturing process.

3
1.3 Properties:
Although formaldehyde is a gas at room temperature, it is voluntarily soluble in water. It is most
normally sold as a 37 % aqueous solution with trade names such as formalin or formol. In water,
formaldehyde changes to the hydrate CH2(OH)2. Thus formalin contains very little H2CO. These
solutions typically contain a few percent methanol to limit the range of polymerization.
Formaldehyde shows most of the chemical properties of the aldehydes, but that it is more
reactive. Formaldehyde is a good electrophile. It can contribute in electrophilic aromatic
substitution reactions with aromatic compounds and can go through electrophilic addition
reactions with alkenes. In the existence of basic catalysts, formaldehyde go through a Cannizaro
reaction to produce formic acid and methanol. Formalin reversibly polymerizes to produce its
cyclic trimer, 1, 3, 5-trioxane or the linear polymer polyoxymethylene. Because of the creation of
these derivatives, formaldehyde gas diverges strongly from the ideal gas law, especially at high
pressure or low temperature. Formaldehyde is voluntarily oxidized by atmospheric oxygen to
form formic acid. Formaldehyde solutions should be protected from air [25]
.
Physical& Thermal Properties:
Table 1.1: Physical & Thermal Properties
Physical Properties
Boiling point at 101.3 kPa -19.2 o
C
Melting point -118 o
C
Density at –80 o
C 0.9151g/cm3
Molecular weight 30.03
Thermal Properties
Heat of formation at 25 o
C -115.9+6.3 kJ/mol
Heat of combustion at 25 o
C 561.5 kJ/mol
Heat of vaporization at –19.2 23.32 kJ/mol
Specific heat capacity at 25o
C 35.425 J/mol K
Entropy at 25o
C 218.8 kJ/mol K
Flash Point 310o
F (154o
C)
Auto Ignition Temp 932o
F (499o
C) [1]

4
1.4 Reactions of the Product:
Dehydrogenation of methanol:
𝐶𝐻3 𝑂𝐻 → 𝐻2 𝐶𝑂 + 𝐻2 Δ𝐻= +84 𝑘𝐽/𝑚𝑜𝑙
Partial oxidation of methanol:
𝐶𝐻3 𝑂𝐻 + ½ O2 → 𝐻2 𝐶𝑂 + 𝐻2 𝑂 Δ𝐻= −159 𝑘𝐽/𝑚𝑜𝑙
1.5 Industrial Applications:
Manufacturing Of Glues and Resin:
Due to the higher binding properties of formaldehyde, it is used widely in the production of glues
and resins used in cabinetry, shelving, stair systems, and in other items of home furnishing. Not
only are these glues widely effective, they are also reasonable due to the fact that formaldehyde is
easily accessible. The greatest common products produced from formaldehyde include urea
formaldehyde resin, melamine resin, and phenol formaldehyde resin. These are manufacturing by
the reaction of formaldehyde with urea, melamine, and phenol, respectively. These are strong
glues, and are used in carpentering. These resins are also mold to make different products, and
old for making insulate layers. Melamine formaldehyde resins are solid and are consumed as
paper-impregnating resins, in cover flooring, and in clear coats for automobiles. Phenol
formaldehyde resins are used as binders in structural wood panels. Formaldehyde resins give wet
strength of products that is facial wipes, paper napkins, etc.
As a Disinfectant:
Formaldehyde is a extremely effective disinfectant. It fully negates the actions of bacteria, fungi,
yeast and molds. Aqueous solution of formaldehyde can kill bacteria, and it is used in the
treatment of skin infections. It is also used to deactivate toxic bacterial products for the
manufacturing of vaccinations for certain infections. Methylamine, a derived of formaldehyde, is
used to treat urinary tract infections. Certain current ointments also use derivatives of
formaldehyde. However, these might not be safe for longstanding use. However, formaldehyde
has a pungent scent that causes severe frustration to the nose and eyes, and this is the reason for
its restricted use. However, many companies have just been successful in manufacturing a
processed form of the chemical, which is not as irritable, yet is an effective disinfectant.

5
Textile Industry:
Formaldehyde also discovers usage in the textile industry where it is added to dyes and pigments.
This helps the pigments to bound better with the fabric, thus avoiding the colors from fading.
Formaldehyde-based resins are used to increase a fabric's resistance to folds and wrinkles.
Automobile Industry:
Key constituents of automobiles are produced using formaldehyde-based products. Since phenol
formaldehyde resins are resistant to fire and high temperatures, they are used to production
automobile parts, such as brake linings.
Preserving Cells and Tissues:
Formaldehyde solution is used in laboratories for the safety of human and animal. A 4% solution
is used for the same. If you're doubting how formaldehyde conserves cells and tissues, it is by the
cross-linking of primary amino groups in proteins with neighboring atoms of nitrogen in protein
or DNA, over a -CH2 linkage.
As an Embalming Agent:
Embalming is a process which briefly stalls the decay of human remains. Formaldehyde is one of
the embalming agents. It also repairs those tissues that are accountable for the firmness of the
muscles in an embalmed body. A normal use of formaldehyde is in the production of ink. So,
whether it is the ink that we use in our printers, or the one used for print books, formaldehyde is a
key constituent. Formaldehyde-based resins are used in the natural gas and petroleum industries
to get improved the yield of these fuels. Hexamine, a derived of formaldehyde, is used as a
component in the manufacture of the quick-tempered RDX. Formaldehyde is mixed with
concentrated (H2SO4) sulfuric acid to form Marquis Reagent, which is used as a spot-test to
detect alkaloids and other compounds. Formaldehyde is added to paints as a stabilizer. It is also
used as a chemical adding in cosmetics. Formaldehyde is used in the manufacturing of polyacetal
which are thermoplastics used in electrical and electronic application.
1.6 Handling:
Formaldehyde should be associated only in original container, fully labeled and deposited
properly inside the way of transportation to avoid out of order up, leakage or breakage.
Formaldehyde should never be opened, mixed or transfer to sample vessels at any time inside a
closed vehicle. A Materials Safety information Sheet (MSDS) should be in the control of the
customer and complete reachable to those prepared by this chemical. At all period, formaldehyde
should only be handled, mixed or added as example containers with the topmost care, in

6
ventilated regions such as open air table if in the field and below an right fume hood if in the
laboratory. Formaldehyde should never be opened or mixed while inside a automobile. If there is
the possibility of splashing, a face protect should be damaged while adding or pouring
formaldehyde. At all times, disposable gloves must be worn to avoid dermal exposure when
management and/or mixing this product. Never smoke or don’t have open flame while working
with formaldehyde.
Storage:
Formaldehyde must be kept in a cool, dry, well-ventilated zone and properly labeled.
Formaldehyde should never be kept in automobiles except to carriage to and from field for the
period of diversity operation. Used formaldehyde, either from leak clean-up or from actions
produced from the process of change-out of sample containers must be kept in a properly label
dangerous waste container and made accessible for recycling under Resources Conservation
Recovery Act (RCRA) protocols. Storing of unwanted formaldehyde should be in a region not
frequented by the general population or responsibility workers and should be in an region not
subject to heat cycles and well ventilated.
Store formaldehyde in label, chemically well-suited containers, away from heat and flame.
Always keep in large-volume containers on a low, safe shelf or in another site where they will not
be accidentally leaked or hit over. Containers bigger than 4L (1 gallon) should be kept in
secondary containment. Do not keep formaldehyde bottles in any area where a leakage would
flow to a drain.
Safety:
Because of formaldehyde’s danger, containing human carcinogenicity, Cal/OSHA has passed
specific system (Title 8, California Code of Regulations, Section 5217) concerning its safe
handling. The following basics must be included in a formaldehyde safety program.
A laboratory-specific Standard Operating Procedure for the use of formalin formaldehyde must
be established. Employees who handle formaldehyde must bring together familiar preparation on
the dangers of formaldehyde and what to do in case of a contact or leak. Coverage monitor may
be required to confirm that employees are not over-exposed. Formaldehyde should always be
used with acceptable ventilation, rather in a fume hood, to minimize breath of formaldehyde
vapor.
Exposure Limit:
The legal on far above the ground permissible exposure limit (PEL) is 1 p/m in an 8-
hourworkday. Short-term exposure (15 minutes) is restricted to 2 p/m while the attainment level
for formaldehyde is 0.5 p/m.

7
1.7 Disposal:
Dissolve or mix the material with a flammable solvent and burn in a chemical furnace equipped
with an afterburner and scrubber. Notice all federal, state, and local environmental procedures.
Spill Procedure:
Evacuate region. Wear self-contained inhalation apparatus, rubber boots and heavy rubber
gloves. Cover with lime or soda ash and abode in closed containers for removal. Ventilate region
and wash leak site after material pickup is complete. Combustible Liquid
Fire Hazards: Extinguisher: Water spray, Carbon dioxide, dry chemical powder or suitable
foam. Special Procedure: Wear self-contained breathing apparatus and protective clothing to
avoid contact with skin and eyes, wear rubber gloves. Unusual Fire hazards: Produces toxic
fumes under fire conditions.
1.8 Shipping:
Formaldehyde should be conveyed only in original container, fully labeled and kept properly
within the automobile to avoid shifting, leakage or breakage. Formaldehyde should never be
opened, mixed or shifted to sample vessels at any time inside a closed automobile. A Materials
Safety Data Sheet (MSDS) should be in the control of the user and made accessible to those
working with this chemical. Shipped in drums, barrels and bottles or carboys. Generally sold and
transported as a 37%-40% aqueous solution, and under certain conditions may become a white
solid. If carried in kegs or barrels there is generally a loss in weight and corrosion of the
fastenings if these are of metal. May produce acidity; this causes significant depreciation and is
generally due to the presence of inherent impurities. If packed in a shipping container, on
unpacking, time should be allowed for spreading of any fumes, before entering container.
1.9 Motivation for the Project:
Motivation for this project is originated in sale department as a result of customer request and to
meet the competing products. And due to increasing demand of formaldehyde it is necessary to
make our intention toward formaldehyde production. It is largely used in Industrial Application.
And in Pakistan it has more demand than its Production. So we import formaldehyde from others
countries Mostly from Germany Iran and Saudi Arabia. In last year 2016 it import was of 183000
of US Dollars, this shows the demand of formaldehyde in Pakistan. Price of Formaldehyde is in
between $350-$400/ton.

8
1.10 Feasibility:
World Formaldehyde Production to Beat 52 Million Tons in 2017. Formaldehyde is the
maximum commercially significant aldehyde. Urea-, phenol-, and melamine-formaldehyde resins
(UF, PF, and MF resins) account for nearly 70% of world demand for formaldehyde in 2015;
other huge applications include polyacetal resins, pentaerythritol, methylene is(4-phenyl
isocyanate) (MDI), 1,4-butanediol (BDO), and hexamethylenetetramine (HMTA).World
consumption demand of 37% formaldehyde is estimate to raise at an average annual rate of about
4% from 2015 to 2020.Between 2010 and 2015, world capacity for 37% formaldehyde increased
at an average annual rate of about 3%, slightly behind world consumption, which increased at an
average annual rate of 4.4% through the same period.
Figure 1.2: World Consumption Data
Formaldehyde resins are used in the wood products industry largely as glues. Growth of these
resins is toughly correlated to construction/restoration activity (which accounts for over 50% of
consumption), and to a lesser degree, the automotive industry.
China is the single major market for formaldehyde, accounting for 42% of world consumption
demand in 2015; other countries with big markets include the United States, Germany, the
Netherlands, Spain, Italy, Belgium, Poland, Russia, India, South Korea, Japan, Brazil, and
Canada. China is estimate to involvement high growth rates and important volume increases in
demand for 37% formaldehyde during 2015–2020. Demand for 37% formaldehyde in the United
States is estimate to grow reasonably, mainly driven by UF resins, PF resins, and MDI. Central
Europe.

Chapter No. 2 Manufacturing Process
9
Chapter No.2
2 Manufacturing Process

Chapter No.2 Manufacturing Process
10
2.1 Production Methods:
For making Formaldehyde there are mostly two methods are used.
Silver Catalyst Method
Metal Oxide Catalyst Method [14]
But we are interested to make formaldehyde by Silver Catalyst Method
2.2 Silver Process
The silver process for the making of formaldehyde uses a silver catalyst, over which partial
oxidation and dehydrogenation of methanol take place. The reactor feed is a mixture of air, steam
and methanol, which is on the methanol-rich side of a flammable mixture and the reaction of
oxygen is almost complete. Reactions 1, 2 are the key reactions that occur during the conversion
of methanol to formaldehyde using the silver process. Reactions 3, 4, are secondary reactions,
making by-products. Extra by-products are methyl formate, methane and formic acid.
CH3OHCH2O + H2 H = +84 kJ/mol
CH3OH + ½ O2 CH2O + H2O H = -159 kJ/mol
CH2O CO + H2 H = 12.5 kJ/mol
CH3OH + 3
/2 O2 CO2 + 2 H2O H = -674 kJ/mol [17]
Process Description:
Between 50 and 60% of the formaldehyde is made via reaction 2 and the rest by reaction 1, and
this combination gives a net exothermic result. The silver catalyzed reaction mechanism will be
discussed in more detail in the next section.
The ratio of methanol to water (as steam) in the feed is normally 60:40. Steam is added to the
feed for three main reasons. It rises the total moles present, which raises the equilibrium
conversion of the endothermic reaction 1 (this reaction is preferred by high temperature, low
pressure and a high value of total moles). A second reason for the adding of steam is that it
avoids damage to the catalyst. It stops sintering of the silver (which results in loss of activity) and
reduces the rate of creation of carbonaceous deposits on the silver (that decrease the active
region). Steam also acts as a heat sink. The predominant means of temperature control is the
addition of additional methanol or steam. However, these additions are bound by the wanted
composition of the formaldehyde product. The ratio of methanol to oxygen in the feed to

11
industrial reactors is about 2.5. Since the reaction is lead adiabatically, it is probable to disturb the
net exothermicity and reaction temperature increase by changing the quantity of air fed to the
reactor. The feed move in the reactor at a temperature extensively below the reactor leaving
temperature. There are two types of the silver process used. One includes the complete
conversion (97-98%) of methanol and is well-known as the BASF process. In this process silver
is used in the form of crystals and the reaction is carried out at 680 - 720 °C (at atmospheric
pressure). The feed is superheated and fed to the reactor where it permits over a bed of silver
crystals 25 - 30 mm thick. The temperature is high enough to let complete conversion (rate and
equilibrium conversion of the endothermic dehydrogenation reaction (1) increase with
temperature). Gases are cooled when they leave the reactor (to avoid unwanted side reactions)
and then fed to an absorption column where formaldehyde is wash out, giving a product that has
40-55 wt.% formaldehyde, 1.3 wt% methanol and 0.01 wt% formic acid. The yield ranges
between 89.5 and 90.5%. The largest well-known reactor for this process has a diameter of 3.2 m
and an annual production of 72000 tons, calculated as 100% formaldehyde.
The second type of the silver process includes incomplete conversion and distillative recovery of
methanol. Superheated feed passes over as bed of silver crystals 1-5 cm thick or through layers of
silver gauze. The reactor temperature lies in the range of 600-650°C. At these relatively low
temperatures the undesirable secondary reactions are suppressed. The oxygen conversion is
complete and the methanol conversion is between 77 and 87%. The gases are cooled after exit the
catalyst bed and enter to an absorption column. The product includes about 42 wt% formaldehyde
and is lead to a distillation column to recover and recycle unreacted methanol. After exiting the
distillation column the formaldehyde solution is generally fed to an anion exchange unit to
decrease the formic acid content to less than 50 mg/kg. The final product include up to 55 wt%
formaldehyde and less than 1% methanol. The overall yield is between 91 and 92%. The tail gas
for the silver process contains about 20% hydrogen and is burnt to produce steam and eliminate
releases of carbon monoxide and other organics [2]
.
2.3 Metal Oxide Process:
Main Reaction:
CH3OH + ½ O2 CH2O + H2O H = -159 kJ/mol
CH3OH + 3
/2 O2 CO2 + 2H2O H = -674 kJ/mol
CH2O + O2 CO2 + H2O H = -519 kJ/mol
Process Description:
The oxide process for formaldehyde making uses a metal oxide (modified iron molybdenum-
vanadium oxide) catalyst. The feed mixture of steam, air and methanol is thin in methanol (to

12
prevent the explosive range) and nearly complete conversion of methanol is obtained (98-99%).
The reaction takes place at 250-400°C. All of the formaldehyde is produce via reaction 2 (the
exothermic ox dehydrogenation of methanol). By-products are carbon monoxide, dimethyl ether,
carbon dioxide and formic acid. Overall yields are in the range of 88 - 92 %. The process starts
with the vaporization of methanol. It is then mixed with air (and optional exhaust/tail gas) and
passed over catalyst-filled tubes in a heat exchanger reactor. A heat transfer fluid permits
circulates outside the tubes and vaporizes, eliminating the heat of reaction. This fluid is then
condensed to make steam. The gases are cooled to 110°C in a heat exchange unit and then
transportable to the bottom of an absorber. Water is added to the top of the column, and the
quantity can be change to control the product concentration. After exit the column the product is
fed over an anion exchange unit to decrease the formic acid content. The final product includes
up to 55 wt% formaldehyde and 0.5-1.5 wt% methanol. The tail gas from the oxide process did
not burn by itself as the flammable content (dimethyl ether, carbon monoxide, methanol and
formaldehyde) is only a few percent. It can be combust in a catalytic furnace or by adding fuel.
2.4 Comparing the Silver and Oxide Processes:
Apart from the catalyst used and the reaction mechanisms, some important differences between
the silver process and the oxide process are:
1. The reactor is run adiabatically for the silver process, while a heat exchanger reactor is used for
the oxide process. Suitable temperature control is needed for the oxide process to attain 99%
conversion. If the temperature is allowed to increase above 470°C, the side reaction containing
the formation of carbon monoxide and water from formaldehyde and oxygen rises significantly.
2. The tail gas from the oxide process is noncombustible, while the tail gas from the silver
process can be combust able. The tail gas from the silver process contains hydrogen and it is
likely that there are other uses for the hydrogen.
3. Even when recycled gas is used (to decrease the oxygen concentration of the feed and therefore
the quantity of air needed to prevent the flammable range), the total volume of gas passing over
the oxide process is 3-3.5 times that of the silver process. This means that the equipment used for
the oxide process must have a greater capacity. The absorption column in particular is much
higher.
4. The silver process does not need ion exchange to eliminate formic acid. The oxide process
makes more formic acid, requiring the extra step to eliminate it. Overall, it seems that the silver
process has bigger PI potential than the oxide process. The oxide process already relies on heat
exchange in the reactor, while the silver process has potential for development with the use of
heat exchange to control the reactor temperature. The silver process makes hydrogen as well as
formaldehyde, which could be made use of in more economically valuable ways. It appears that it
may also be possible to raise the quantity of hydrogen manufactured. The oxide process uses

13
bigger volumes of gas than the silver process, meaning that except the need for some of the gas
can be detached it may be more difficult to make compact units for the oxide process than the
silver process. When creation compact units, the need for formic acid elimination is another
disadvantage of the oxide process as it means another step must be incorporated into the unit. For
these reasons, the use of the silver process for the Process Increase of the production of
formaldehyde will be investigated rather than the oxide process.
Table 2.1: Comparison of Processes
Sr.No. Silver Catalyst Metal Oxide Catalyst
1 Process run adiabatically Process Need Heat Exchanger
2 Tail Gases Can be Combustible Tail Gases Cannot be Combustible
3
Gases use to prevent the flammable
range is lower than the metal oxide
process.
3-3.5 time greater gas use to prevent the
flammable range in this process than
silver process.
4
Silver process did not need ion
exchange to eliminate formic acid.
Metal oxide process needs an extra setup
to eliminate formic acid because it
produces more formic acid than Silver
process.
5
Silver process also produces hydrogen
with Formaldehyde which makes it
more economical.
This process use bigger volume of gas
than silver process. And hydrogen gas
did not produce in this process.
6
Operating cost of Silver Process is less
than Metal Oxide Process.
Operating cost of Metal Oxide is greater
than Silver Process.
2.5 Process Selection:
For making Formaldehyde we are selecting Silver Catalyst Process because for making
formaldehyde uses silver catalyst over which partial oxidation and dehydrogenation of methanol
occurs. While for Production of formaldehyde uses oxide catalyst over which only partial
oxidation is occur. And Tail gases from silver catalyst process can burn while from metal oxide
catalyst process tail gasses did not burn. There are more chances of producing by product in the
metal oxide catalyst process while in the silver catalyst process this chance of producing by-

14
product is very low. That’s why we select Silver Catalyst process. Moreover operating cost of
silver process is less than metal oxide process.
2.6 Capacity Selection and Its Justification:
Production of Formaldehyde in Pakistan is 340000 MT/Year. And Demand of Formaldehyde in
Pakistan is 400000 MT/Year
Capacity of Formaldehyde required to produce.
Demand-Consumption = Capacity
400000 – 340000 = 60000 ton/year
To meet this production capacity 60000 ton/year we have to produce 200 ton/day [23] [24]
.
Capacity per day * Working Day of plant = Required production capacity per year
200*330 = 66000 ton/year
We select capacity of 200 ton/day to fulfill the need of Pakistan.
Price of formaldehyde is 42-45 Rs/Kg
Table 2.2: Capacity Selection
Sr.No Companies That are Producing CH2O Capacity of CH2O ton/year
1 Super Chemical (Karachi and Lahore) 100000 ton/year
2 Dyena (Karachi and Lahore) 59000 ton/year
3 ZRK (Peshawar) 45000 ton/year
4 Wah Noble (Wah Cantt.) 30000 ton/year
5 Other Rest Companies 106000 ton/year
6 Total 340000 ton/year
2.7 Silver Process Description and Flow Sheet:
In early formaldehyde plants methanol was oxidized over a copper catalyst but this process has
been almost completely replaced with silver. The silver catalyzed reaction occurs at essentially at
atmospheric pressure and 600 to 650 C0
and can be represented by two simultaneous reactions
CH3OH + ½ O2 → HCHO + H2O
CH3OH → HCHO + H2

15
Process Technology:
Between 50 and 60% of formaldehyde is formed by the exothermic reaction and the remainder by
endothermic reaction with the net results of a reaction exothermic. Carbon monoxide, methyl
formate, and formic acid are byproducts. In addition there are also physical loses, liquid phase
reactions, and small quantities of methanol in the product, resulting in an overall plant yield of
86-90 %( based on methanol).
A typical formaldehyde plant (76-79) employing silver catalyst. A feed mixture is generated by
spraying air into pool of heated methanol and combining the vapors with the steam. The mixture
passes through a super heater to a catalyst bed of silver crystals or layers of silver gauze. The
product is then rapidly cooled in a steam generator and then in water cool heat exchanger and fed
to the bottom of an absorption tower. The bulk of the methanol water and formaldehyde is
condensed in the bottom water-cooled section of the tower and almost complete removal of
methanol and formaldehyde from the tail gas occurs in the top absorber by counter current
contact with clean process water. Absorber bottoms go to a distillation tower where methanol is
recovered for recycle to the reactor. The base stream from distillation aqueous solution of
formaldehyde is usually sent to an anion exchange unit which reduces the formic acid to
specification level. The product contains up to 55% formaldehyde and less than 1.5% methanol.
A typical catalyst bed is very shallow (10 to 50 mm) (76, 77). In some plants the catalyst is
contained in numerous small parallel reactors; in others, catalyst bed diameters up to 1.7 and 2.0
m (77, 80) and capacities of up to 135,000 t/yr. reactor are reported. The silver catalyst has a
useful life of three to eight months and can be recovered. It is easily poisoned by traces of
transition group metals and by sulfur.
The reaction occurs at essentially adiabatic conditions with a large temperature rise at the inlet
surface of the catalyst. The predominant temperature Control is thermal ballast in the form of
excess methanol or steam, or both, which is in the feed. If a plant is to produce a product
containing 60 to 65% formaldehyde and no more than 1.5% methanol, the amount of steam that
can be added is limited, and both excess methanol and steam needed as ballast. Recycled
methanol required for 50-55% product is 0.25-0.50 parts per pact of fresh methanol.
With the increase in energy cost, maximum methanol conversion is desirable eliminating the
need of energy-intensive distillation for methanol recovery. If a dilute product containing 40 to
44% formaldehyde and 1.0 -1.5% methanol is acceptable then the ballast steam can be increased
to a level where recycled methanol is eliminated with significant saving in capital cost and
energy. In another process, tail gas from the absorber is recycled to the reactor. This additional
gas plus steam provides the necessary thermal ballast without the need for excess methanol. This
process can produce 50% formaldehyde then with about 1.0% methanol without a distillation
tower. Methanol recovery can be obviated in two-stage oxidation systems where, for example,
part of the methanol is converted with a silver catalyst, the product is cooled, excess air is added,

16
and the remaining methanol is converted over a metal oxide catalyst such as that described below
(85). In another two-stage process, both first and second stages use silver catalysts (86-88).
Formaldehyde-methanol solutions can be made directly from methanol oxidation product by
absorption in methanol. The absorber tail gas contains about 20 mol% hydrogen and has a higher
heating value of ca 2420 kJ/m3 (65 Btu/SCF). With increased fuel costs and in-creased attention
to the environment and tail gas is burned for the twofold purpose of generating steam and
eliminating organic and carbon monoxide emissions.
Aqueous formaldehyde is corrosive to carbon steel, but formaldehyde in the vapor phase is not.
All parts of the manufacturing equipment exposed to hot formaldehyde solutions must be a
corrosion-resistant alloy such as type-316 stainless. Theoretically the reactor and the upstream
can be carbon steel but in practice alloys are required in this part of the plant to protect the
sensitive silver catalyst from metal contamination [5]
.

17
Flow Sheet of Production of Formaldehyde Using Silver Process:
S
S
Air Blower
Methanol
Feed
Pump-1
Vaporizer
CW
Silver Catlyst
Reactor
Tail Gas
Process
Water
CW
Pump-2
Absorption
Tower
Distillation
Tower
Pump-3
Pump-4
S
CW
Formaldehyde
Product
55 %
Methanol
Recycle
CW
S
S
S = Steam;
CW = Cooling
Water
MF-01
Air-02
Steam-
03
V-04
R-05
AT-06
AT-07
DT-08
AT-09
PW-10
AT-11
DT-12
DT-13
DT-14
DT-15
Figure 2.1: Flow Sheet of Formaldehyde using Silver Catalyst

Chapter No.2 Manufacturing Processes
18
2.8 Metal Oxide Catalyst Process:
The Formax process established by Reichhold chemicals to make formaldehyde through direct
catalytic oxidation of methanol and some other by-products such as carbon monoxide and
dimethyl ether produced. In 1921, the oxidation of methanol to formaldehyde with vanadium
pentoxide catalyst was introduced to and patented. Then in 1933, the iron-molybdenum oxide
catalyst was also patented and used till the early 1990’s. Developments to the metal oxide
catalyst were done through the metal composition, inert carriers and preparation methods. The
first commercial plant for the production of formaldehyde using the iron-molybdenum oxide
catalyst was put into achievement in 1952. Unlike the silver centered catalyst in this project, the
iron-molybdenum oxide catalyst produces formaldehyde from the exothermic reaction (1)
entirely. Under atmospheric pressure and 300 – 400 o
C, methanol conversion inside the reactor
could reach 99% and a yield of 88% - 92%.
The air is provided by the turbo blower. Methanol to the plant is provided by the pump and is
inserted into the air stream through a spray nozzle ring. The air methanol mixture is then permits
through the methanol vaporizer, where the methanol is vaporized.
The oxidation of methanol takes place in a fixed bed reactor with 2450 stainless steel tubes. The
tubes are loaded with the metallic oxide catalyst to a specific deepness. The bottom and top
sections of the tubes are occupied small inert rings to develop the heat transfer. The reactor tubes
are surrounded by the liquid heat transfer medium, Dowtherm by which part of the heat of the
reaction is detached.
The gas mixture entering the top of the catalyst tubes is preheated by the boiling Dowtherm in the
reactor shell, while passing over the upper inert rings in the catalyst tube. As the gas reaches the
catalyst, the reaction starts and temperature increases quickly to a maximum. Then temperature
drops because of the conversion of the Dowtherm from liquid as Dowtherm is heat transfer fluid.
The reactor gasses pass out of the reactor bottom and into the vaporizer. In the vaporizer heat
transfer arises and the methanol from liquid is changed into the gas by this heat and from there
the gasses continue to the absorption tower.
The lower part of absorption tower contains of a spray section with several spray nozzles. The
upper part consists of a 27trays with 64 bubble cap.
When the hot entering gas first reaches the spray section it is cooled by the circulating solution of
formaldehyde concentration of final product. The heat of the absorption is detached by cooling
water pumped through coils located below the liquid level on each tray. The Dowtherm is
circulated by thermo-siphon circulation over the reactor shell and the Dowtherm vapor separator.
In the separator the Dowtherm vapors are separated from the liquid and continues further to the

19
condenser, where the vapors are condensed liquid flows them back over the separator and further
to the reactor again.
The Dowtherm condenser which is a shell and tube pipe heat exchanger is operated as a steam
boiler. This steam is further used.

20
Flow Sheet of Production of Formaldehyde Using Metal Oxide Process
Blower Storage Tank
Condensor
Air
SeparatorHeater
Reactor
NAOH
Process Water
Formaldehyde
Methanol
Evaporator
Figure 2.2: Flow Sheet of Formaldehyde Using Metal Oxide Catalyst

21
2.9 Process Flow Diagram Of Silver Process:
O2 = 4444.444 kg/hr
N2 =14629.63 kg/hr
Air
H2O(g) = 2000 kg/hr
CH3OH=9661.836 Kg/hr
O2 = 4444.444 kg/hr
N2 = 14629.63 kg/hr
CH3OH = 9661.836 kg/hr
H2O = 2000 kg/hr
O2 = 1903.768 kg/hr
N2 = 14629.63 kg/hr
CO2 = 21.08 kg/hr
CO = 13.87 kg/hr
H2 = 236.715 kg/hr
Process
Water
T= 303 K
P= 1.8 atm
H2O = 9170.57632 kg/hr
Outlet =30735.91 kg/hr
Outlet 23073.33 kg/hr
Methanol
Feed
T= 298 K
P= 1 atm
Tail Gas
T= 438 K
T= 338 K
P= 1.5 atm
T= 350 K
P = 1.66 atm
T= 358 K
T= 353 K
CH3OH = 785.11304 kg/hr
H2O = 139.65797 kg/hr
CH2O =83.144928 kg/hr
CH3OH = 7.90435 kg/hr
H2O = 9016.461 kg/hr
CH2O =8231.348 kg/hr
Steam
P-100
B-101
1
Methanol
Recycle
V-100
R-100
A-100
D-100
P-101
E-100
T= 303 K
T= 298 K
P= 2.4 atm T= 393 K
P= 2 atm
T= 338K
P= 1.8 atm
T= 473K
P= 1.7 atm
T= 298 K
P= 2 atm
T= 393 K
P= 2 atm
2
4
3
5
6
7
8
9
10
11
12
14
13
CW= 303 K
T= 323 K
15
16
17
18
19
20
21
22
23
24 25
26
27
CW= 1425 kg/hr
Formaldehyde Product
37%
Storage Tank
CW=1100 Kg/hr
S=5838.87 kg/hr
T= 355 K
P = 1.66 atm
Figure 2.3: Process Flow Diagram of Formaldehyde Using Silver Catalyst

22
Table 2.3: Components and flow rates
Components
1 2 3 4 6 7 8 9 10 11 12
kg/hr kg/hr kg/hr kg/hr kg/hr kg/hr kg/hr kg/hr kg/hr kg/hr kg/hr
CH3OH 9661.83 9661.83 - - 9661.83 793.04 - 793.04 - 7.93 785.11
O2 - - 4444.44 - 4444.44 1903.76 - - 1903.76 - -
N2 - - 14629.63 - 14629.63 14629.63 - - 14629.63 - -
H2O - - - 2000 2000 4858.26 9107.53 13965.8 - 13826.14 139.65
CO - - - - - 13.87 - - 13.87 - -
CO2 - - - - - 21.80 - - 21.80 - -
H2 - - - - - 236.71 - - 236.71 - -
CH2O - - - - - 8314.49 - 8314.49 - 8231.34 83.14
Total
9661.836 9661.836 19074.07 2000 30735.91 30735.91 9107.53 23073.33 16770.11 22065.41 1007.91
30735.91 30735.91 39843.45 39843.45 23073.33
Temp 298 K 393 K 298 ℃ 493 K 393 K 473 K 303 K 338 K 438 K 358 K 350 K

Chapter No. 3 Material Balance
23
Chapter No. 3
3 Material Balance

Chapter No.03 Material Balance
24
3.1 Main Reactions:
CH3OH CH2O + H2
CH3OH + ½ O2 CH2O + H2O
1 kmol/hr CH3OH 1 kmol/hr CH2O
3.2 Capacity:
=200 ton/day
= (200*1000)/24 = 8333.33 kg/hr
Actual amount of formaldehyde CH2O =277.778kmol/hr
Theoretical amount of formaldehyde CH2O
Theoretical = actual/yield =301.932 kmol/hr
Amount of O2 =138.889kmol/hr
Amount of N2 =522.487kmol/hr
Steam Ratio: =111.111kmol/hr
3.3 Material Balance at Vaporizer (V-100) & Mixing Point:
T= 298 K
P= 2.4 atm
T= 393 K
P= 2 atm
T= 443 K
Steam= 5838.87 Kg/hr
T= 443 K
Condensate= 5838.87 Kg/hr
V-100
1
16
2
17
Figure 3.1: Material Balance V-100

25
Table 3.1: Material Balance at V-100
Components
Inlet Stream kg/hr Outlet Stream Kg/hr
1 2
CH3OH 9661.83 9661.83
Mixing Point Vaporizer Air and Steam
19074.07+2000+9661.83 = 30735.91
3.4 Material Balance at Reactor (R-100):
T= 393 K
P= 2 atm
O2 = 4444.444 kg/hr
N2 = 14629.63 kg/hr
CH3OH = 9661.836 kg/hr
H2O = 2000 kg/hr
T= 473 K
P= 1.7 atm
O2 = 1903.768 kg/hr
N2 = 14629.63 kg/hr
CH3OH = 793.0435 kg/hr
H2O =4858.21 kg/hr
CH2O =8314.493 kg/hr
CO2 = 21.08 kg/hr
CO = 13.87 kg/hr
H2 = 236.715 kg/hr
R-100
6
18
7
CW=1100 Kg/hr
19
Figure 3.2: Material Balance at R-100
3.4.1 For Reaction 1:
CH3OH CH2O + H2
Overall conversion = 0.98

26
For Reaction 1
CH3OH CH2O + H2
Conversion 0.40
Overall Methanol Conversion 98%
40% of 98 %
Methanol = 301.9324 kmol/hr
Methanol Reacted = 118.3575 kmol/hr
Methanol Remains = 183.5749 kmol/hr
Formaldehyde Produced = 118.3575 kmol/hr
H2 Produced = 118.3575 kmol/hr
Table 3.2: Material Balance R-100
Components
Inlet Stream Kg/hr Outlet Stream Kg/hr
6 7
CH3OH 9661.83 5874.39
O2 4444.44 4444.44
N2 14629.63 14629.63
H2O 2000 2000
CO - -
CO2 - -
H2 - 236.71
CH2O - 3550.72
Total 30735.91 30735.91
3.4.2 For Reaction 2:
60% of 98%
Methanol = 183.5749 kmol/hr
O2 = 138.8889 kmol/hr

27
Methanol Reacted = 158.7923 kmol/hr
Methanol Remaining = 24.78261 kmol/hr
O2 Reacted = 79.39614 kmol/hr
O2 Remains =59.49275 kmol/hr
Formaldehyde produced = 158.7923 kmol/hr
CO = 0.495652 kmol/hr
CO2 = 0.495652 kmol/hr
Overall H2O Produced = 269.9034 kmol/hr
Table 3.3: Material Balance R-100
Components
6 7
CH3OH 5874.396 793.04
O2 4444.44 1903.76
N2 14629.63 14629.63
H2O 2000 4858.26
CO - 13.87
CO2 - 21.80
H2 236.71 236.71
CH2O 3550.72 8314.49
Total 30735.91 30735.91

28
3.5 Material Balance at Absorber (A-100):
Process
Water
T= 303 K
P= 1.8 atm
H2O = 9170 kg/hr
T= 338
P= 1.5 atm
CH3OH = 793.0435 kg/hr
H2O =4858.21 kg/hr
CH2O =8314.493 kg/hr
Tail Gas
AT-100
T= 473 K
P= 1.7 atm
O2 = 1903.768 kg/hr
N2 = 14629.63 kg/hr
CH3OH = 793.0435 kg/hr
H2O =4858.21 kg/hr
CH2O =8314.493 kg/hr
CO2 = 21.08 kg/hr
CO = 13.87 kg/hr
H2 = 236.715 kg/hr
T= 438 K
P= 1.5 atm
O2 = 1903.768 kg/hr
N2 = 14629.63 kg/hr
CO2 = 21.08 kg/hr
CO = 13.87 kg/hr
H2 = 236.715 kg/hr
7
8 10
9
Figure 3.3: Material Balance at A-100
Methanol and Formaldehyde are very soluble in water:
Formaldehyde solubility in Water = 550kg/m3
= 15.110 m3/hr
Converting into kg/hr we have to multiply with water density:
= 15110 kg/hr
Water Added = 9170.57632 kg/hr
Tail Gases:
O2, N2, CO2, CO
Product from stream 7:
CH3OH, CH2O, H2O

29
Table 3.4: Material Balance at A-100
Components
7 8 9 10
CH3OH 793.04 - 793.04 -
O2 1903.76 - - 1903.76
N2 14629.63 - - 14629.62
H2O 4858.26 9107.53 13965.8 -
CO 13.87 - - 13.87
CO2 21.80 - - 21.80
H2 236.71 - - 236.71
CH2O 8314.49 - 8314.49 -
Total 39843.446 39843.446
3.6 Material Balance at Distillation Tower (D-100):
T= 350 K
CH3OH = 785.11304 kg/hr
H2O = 139.65797 kg/hr
CH2O =83.144928 kg/hr
T= 353 K
CH3OH = 7.90435 kg/hr
H2O = 9016.461 kg/hr
CH2O =8231.348 kg/hr
T= 338 K
P= 1.8 atm
CH3OH = 793.0435 kg/hr
H2O =4858.21 kg/hr
CH2O =8314.493 kg/hr
T= 350 K
P = 1.66 atm
T= 358 K
D-100
11
12
14
13
20
21
22
23
9
CW= 1425 kg/hr
T= 355 K
P = 1.66 atm
Figure 3.4: Material Balance at D-100

30
F = D + W
F.xf = D.xd + W.xw
Top Product: Methanol = 0.99
Bottom Product: Formaldehyde = 0.99, H2O = 0.99
Table 3.5: Material Balance at D-100
Components
Inlet Stream
Kg/hr
Outlet Stream Kg/hr
9 12 11
CH3OH 793.04 785.11 7.93
H2O 13965.8 139.65 13826.14
CH2O 8314.49 83.14 8231.34
Total 23073.33 23073.33
From Bottom:
CH3OH =7.930435/22065.42 = 0.0003594 =0.03%
H2O =13826.14/22065.42 =0.6265 =62.65%
CH2O =8231.348/22065.42 =0.3730 =37.30% [4]

Chapter No. 4 Energy Balance
31
Chapter No. 4
4 Energy Balance

Chapter N0. 4 Energy Balance
32
4.1 Energy Balance on Vaporizer (V-100):
T= 298 K
P= 2.4 atm
T= 393 K
P= 2 atm
T= 443 K
T= 443 K
V-100
1
16
2
17
Figure 4.1: Energy Balance V-100
Table 4.1: Energy Balance at Vaporizer V-100
Components
Inlet Stream
Kg/hr
Outlet Stream
kg.hr
Cp at 345.5 K
1 2 Kj/kg.K
CH3OH 9661.83 9661.83 2.69
T1 = 298 K, T2 = 393 K, Tmean = 345.5 K
Q = mCpΔT
Q=mtotal*Cptotal*(338-298) + ((λ+Cp (373-338))
Q = 1040861.784 kj/hr
λ:latent heat of vaporization of methanol at 338 K = 1100.313 Kj/Kg
For Steam in Vaporizer:
λ steam = 2163.22 kj/kg

33
Temperature = 133.54 ℃
=406.54 K
Q= mλ
m= Q/λ
Steam Flow rate:
m= 1040861.784/2163.22
= 5838.8725 kg/hr
4.2 Energy Balance at Reactor (R-100):
T= 393 K
P= 2 atm
O2 = 4444.444 kg/hr
N2 = 14629.63 kg/hr
CH3OH = 9661.836 kg/hr
H2O = 2000 kg/hr
T= 473 K
P= 1.7 atm
O2 = 1903.768 kg/hr
N2 = 14629.63 kg/hr
CH3OH = 793.0435 kg/hr
H2O =4858.21 kg/hr
CH2O =8314.493 kg/hr
CO2 = 21.08 kg/hr
CO = 13.87 kg/hr
H2 = 236.715 kg/hr
R-100
6
18
7
CW=1100 Kg/hr
19
Figure 4.2: Energy Balance at R-100

34
Table 4.2: Energy Balance at R-100
Components
Inlet Stream
Kg/hr
Cp at 393 K
Outlet Stream
Kg/hr
Cp at 473 K
6 Kj/kg.k 7 Kj/kg.k
CH3OH 9661.83 2.63 793.04 2.8
O2 4444.44 0.94 1903.76 0.96
N2 14629.63 1.04 14629.63 1.05
H2O 2000 1.89 4858.26 1.94
CO - 1.04 13.87 1.06
CO2 - 1.04 21.80 0.98
H2 - 14.46 236.71 14.5
CH2O - 1.3 8314.49 1.41
Total 30735.91 - 30735.91 -
Qin - Qout + Generation - Consumption = Accumulation
T1 = 393 K, T2 = 473 K, Tref = 298 K
Q in = mtotal*Cp*(393-298)
= 4622485 kj/hr
Q out =mtotal*Cp*(473-393)
= 3523734.2 kj/hr
Heat of Reaction:
For Reaction 1
= 84000 kj/kmol
= 177.54 kmol/hr
= 84000*177.54
= 14913360 kj/hr
For Reaction 2:
= -159000 kj/kmol
=118.3541 kmol/hr

35
=-159000*118.3541
= -18817872.6 kj/hr
Adding 1 & 2:
= -18817872.6 + 14913360
= -3904513 kj/hr
L.H.S:
= 4622485 + (-3904513)
=717972.64 Kj/hr
R.H.S:
=-3523734.2 kj/hr
Difference:
= R.H.S-L.H.S
= -2805761 Kj/hr
For Cooling Water:
T1 = 298 K, T2 = 453 K, Tmean = 375.5 K
Cp at 375.5 K = 1.89 Kj/Kg.K
Q=mCpΔT
m= Q/((Cp*ΔT)+λ+(Cp*ΔT)
m= 2805761/((1.89*348)+2257+(1.89*353))
=1100.3202 Kg/hr

36
4.3 Energy Balance at Absorber (A-100):
Process
Water
T= 303 K
P= 1.8 atm
H2O = 9170 kg/hr
T= 338
P= 1.5 atm
CH3OH = 793.0435 kg/hr
H2O =4858.21 kg/hr
CH2O =8314.493 kg/hr
Tail Gas
AT-100
T= 473 K
P= 1.7 atm
O2 = 1903.768 kg/hr
N2 = 14629.63 kg/hr
CH3OH = 793.0435 kg/hr
H2O =4858.21 kg/hr
CH2O =8314.493 kg/hr
CO2 = 21.08 kg/hr
CO = 13.87 kg/hr
H2 = 236.715 kg/hr
T= 438 K
P= 1.5 atm
O2 = 1903.768 kg/hr
N2 = 14629.63 kg/hr
CO2 = 21.08 kg/hr
CO = 13.87 kg/hr
H2 = 236.715 kg/hr
7
8 10
9
Figure 4.3: Energy Balance at A-100
Inlet Absorber:
Table 4.3: Energy Balance at Inlet A-100
Components
Inlet Stream
Kg/hr
Cp at 473 K
Inlet Stream
Kg/hr
Cp at 303 K
7 Kj/Kg.K 8 Kj/Kg.K
CH3OH 793.04 2.8 - -
O2 1903.76 0.963 - -
N2 14629.63 1.051 - -
H2O 4858.261 1.94 9107.53 1.86
CO 13.87 1.06 - -
CO2 21.80 0.98 - -
H2 236.71 14.5 - -
CH2O 8314.49 1.41 - -
Total 30735.91 - 9107.53 -

37
T1 = 473 K, T2 = 303 K, Tref = 298 K
For Gas Stream 7:
Qin = mCpΔT
Qin = 7708168 Kj/hr
For Water Stream 8:
Qin = mCpΔT
Qin = 84927.78 Kj/kg
Adding both we get = 7793096 Kj/hr
Outlet Absorber:
Table 4.4 Energy Balance at Outlet of A-100
Components
Outlet Stream
Kg/hr
Cp at 465 K
Outlet Stream
Kg/hr
Cp at 338 K
10 Kj/kg.K 9 Kj/Kg.K
CH3OH - - 793.04 1.2
O2 1903.76 0.919 - -
N2 14629.63 1.04 - -
H2O - - 4858.26 4.65
CO 13.87 1.04 - -
CO2 21.80 0.847 - -
H2 236.71 14.32 - -
CH2O - - 8314.49 1.22
Total 16805.8 13965.8
T1 = 338 K, T2 = 465 K, Tref = 298 K
For Product Stream 9:
Qout = mCpΔT
Qout = 1325157.69 Kj/hr
For Tail Gases Stream 10:
Qout = mCpΔT

38
Qout = 6467759.30 Kj/hr
Adding both we get = 7793096 Kj/hr
Qin – Qout + Generation = 0
4.4 Energy balance on Distillation Unit (D-100):
T= 350 K
CH3OH = 785.11304 kg/hr
H2O = 139.65797 kg/hr
CH2O =83.144928 kg/hr
T= 353 K
CH3OH = 7.90435 kg/hr
H2O = 9016.461 kg/hr
CH2O =8231.348 kg/hr
T= 338 K
P= 1.8 atm
CH3OH = 793.0435 kg/hr
H2O =4858.21 kg/hr
CH2O =8314.493 kg/hr
T= 350 K
P = 1.66 atm
T= 358 K
D-100
11
12
14
13
20
21
22
23
9
CW= 1425 kg/hr
T= 355 K
P = 1.66 atm
Figure 4.4: Energy Balance at D-100
Reboiler:
Table 4.5: Energy Balance at Reboiler:
Component Kg/hr Cp at 358K, Kj/Kg.K
CH3OH 7.93 1.78
H2O 13826.14 1.88
CH2O 8231.34 1.27
Total 22065.42 -

39
λ mixture = 1035 kJ/kg
Q total = m λ
Q= 22837707 Kj/hr
For Steam:
Pressure = 1 atm
λ= 2250.76 Kj/Kg
m= Q/λ =10146.66 kg/hr
Condenser:
Table 4.6: Energy Balance at Condenser:
Component Kg/hr Cp at 350K, Kj/Kg.K
CH3OH 785.11 1.7
H2O 139.65 1.88
CH2O 83.14 1.24
Total 1007.91 -
λ mixture = 1055 kJ/kg
Q= mλ
Q = 1063351.3 Kj/hr
Water requirement:
T1 = 298 K, T2 = 323 K, Tmean = 310.5 K
Cp = 1.865 Kj/Kg.K
Q=mCp (ΔT)
m=Q/Cp (ΔT)
=22806.463 kg/hr

40
4.5 Energy Balance at Exchanger (E-100):
T= 303 K
P = 1.45 atm
CH3OH = 7.90435 kg/hr
H2O = 9016.461 kg/hr
CH2O =8231.348 kg/hr
T= 353 K
P = 1.66 atm
CH3OH = 7.90435 kg/hr
H2O = 9016.461 kg/hr
CH2O =8231.348 kg/hr
T= 298 K
T= 323 K
E-100
24
26
25
27
Figure 4.5: Energy Balance at E-100
T1 = 353 K, T2 = 303 K, Tmean = 328 K
Cp = 1.873 kJ/kg.K
Q=mCpΔT
=36601.539*(323)
=1830076.9 kJ/hr
For Cooling Water:
T1 = 298 K, T2 = 318 K, Tmean = 308 K
Cp = 4.204 kJ/kg.K
Q=mCpΔT
m= Q/CpΔT
=1830076.9/4.204* (293)
=21765.901kg/h [4] [15]

Chapter No.5 Equipment Selection and Design
41
Chapter No. 5
5 Equipment Selection and Design

42
5.1 Design of Vaporizer (V-100):
Vaporizer:
Vaporizers are heat exchangers which are specially designed to supply latent heat of vaporization
to the fluid. In some cases it can also preheat the fluid then this section of vaporizers will be
called upon preheating zone and the other section in which latent heat is supplied; is known as
vaporization zone but the whole assembly will be called upon a vaporizer.
Vaporizers are called upon to fulfill the multitude of latent-heat services which are not a part of
evaporative or distillation process.
There are two principal types of tubular vaporizing equipment used in industry: Boilers and
Vaporizing Exchangers. Boilers are directly fired tubular apparatus, which primarily convert fuel
energy into latent heat of vaporization. Vaporizing Exchangers are unfired and convert latent or
sensible heat of one fluid into the latent heat of vaporization of another. If a vaporizing exchanger
is used for the evaporation of water or an aqueous solution, it is now fairly conventional to call it
an Evaporator, if used to supply the heat requirements at the bottom of a distilling column,
whether the vapor formed be stream or not, it is a Reboiler; when not used for the formation of
steam and not a part of a distillation process, a vaporizing exchanger is simply called a vaporizer.
So any unfired exchanger in which one fluid undergoes vaporization and which is not a part of
evaporation or distillation process is a vaporizer.
Types of Vaporizers:
 Vertical Vaporizer
 Indirect Fluid Heater
 Electric Resistance Vaporizers
 Tubular Low Temperature Vaporizers

43
T= 298 K
P= 2.4 atm
T= 393 K
P= 2 atm
T= 443 K
T= 443 K
V-100
1
16
2
17
Figure 5.1: Vaporizer V-100
Design Calculations:
Process conditions required
Hot fluid: T1, T2, W, c, s, µ, k, Rd
Cold fluid: t1, t2, w, c, s, µ, k, Rd
For designing the following data must be known
Shell side (Cold Fluid) Tube side (Hot Fluid)
ID = 23(1/4) = 23.25 inches Number and Length = 136, 16’0”
Baffles = 5 in OD, Pitch = 1(1/2) in, 16BWG,
Baffle spacing = 4.65 1(7/8) -in triangular pitch
Passes = 1 Passes = 2
(1) Heat Balance:
Preheat:
TmCQp p 

44
Total flow rate = 21300.7 lb/hr
Enthalpy = 29.5 Btu/lb
Inlet temperature = 77o
F, outlet temperature = 149o
F
∆T = 72o
F
Q p = 45242686.8 Btu/hr
Vaporization:
Enthalpy of vapor at 338 o
F = 23.684 Btu/lb
mTmCvQv 
m = 21300.7 lb/hr
λ = 473.0582 Btu/lb
Inlet temperature = 149, outlet temperature = 248
∆T = 99
Q v = 49944565 Btu/hr
Methanol Q = Qp + Qv
Methanol = 45242686.8 + 49944565 Btu/hr
Methanol = 95187252 Btu/hr
Steam = Qs = 12868.87 * 880 Btu/hr
Steam Qs = 11324606 Btu/hr
(2) ∆t Weighted: (Subscript p and v indicate preheating and vaporization.)
For Preheating Zone:
T1 = 338o
F T2 = 338o
F
t1 = 77 o
F t2 = 149o
F

45
LMTD =
(𝑇1−𝑡2)−(𝑇2−𝑡1)
𝐿𝑛[
(𝑇1−𝑡2)
𝑇2−𝑡1
]
(LMTD) p = 127.48o
F
For Vaporizing Zone:
T1 = 338o
F T2 = 338o
F
t1 = 149o
F t2 = 248o
F
LMTD =
(𝑇1−𝑡2)−(𝑇2−𝑡1)
𝐿𝑛[
(𝑇1−𝑡2)
𝑇2−𝑡1
]
(LMTD) v = 35.177o
F
Q p / (∆t) p = 45242686.8 / 127.48 = 354900.273
Q v / (∆t) v = 49944565 / 35.17 = 1420089.996
∑ q / (∆t) = 354900.273 + 1420089.996 = 1774990.269 o
F
Weighted ∆t = Q/∑ q / (∆t)
Weighted ∆t = 11324606 / 1774990.269 o
F
Weighted ∆t = 6.38009 o
F
Assumption:
From Appendix A Table: A-1
Assume Ud = 500 Btu/hr ft2 o
F
A = Q/Ud*∆t
A = 45242686.8 / (500*127.48)
A = 709.8005 ft2
Tube Specification: 1(1/4) in, 16 BWG

46
Space per linear ft = at = 0.3271 ft2
No. of tubes = N = A/(L*at)
N = 709.8005 / (16*0.3271)
N = 135.62
Select number of tubes, shell ID and passes at1 (1/4) in, OD tubes on 1(9/16) in. triangular pitch
Corrected number of tubes = N = 136
Number of passes = n = 02
Shell ID = 23(1/4) = 23.25 in
Corrected area and overall heat transfer coefficient, UD:
From Appendix A Table: A-2
Area = A = N × L × at = 0.3271*16*136
Area = A = 711.7696 ft2
Ud = Q / A*∆t
Ud = 45242686.8 / (711.7696*127.48) = 498.6168 Btu/hr ft2o
F (corrected)
(3): Tc and tc: Average value of temperature will be satisfactory for preheat zone.
Hot Fluid: Tube Side, Steam Cold fluid: Shell Side, Methanol
Preheating:
(4): Flow area: (4): Flow area:
at =
n
Nta t



144
ft2
as = ID*C’B/144Pt
For 16 BWG and 1(1/4)” O.D as = 23.25*5*0.25/144*1.25
The flow area/tube in2 = at = 0.985 in2
as = 0.16145833 ft2

47
n = number of passes = 2
at = 0.985*136 / 144*2
at = 0.4651389 ft2
(5): Mass velocity: (5): Mass Velocity
s
s
a
w
G 
s
s
a
w
G 
G = 12868.87/0.4651389 G = 21300.7 / 0.16145833
G = 27666.726 lb/hr ft2
G = 131926.92 lb/hr ft2
(6): At Ts = 248 o
F (6): At Ts=113oF (77+149 Avg)
µ = 0.015 µ = 0.4
µ = 0.015*2.42 = 0.0363 lb/ft hr µ= 0.4*2.42= 0.1652893 lb/ft hr
Dia = 1.12/12 = 0.0933333 ft Dia = 0.99/12 = 0.0825 ft

GD
t Re

GD
s Re
Ret = 71135.7 Res = 65848.022
(7): JH = 170
From Appendix A, Figure: A-1
(8): At 113 F (114API):
K (cµ/k) ^ (1/2) = 0.16 Btu/hr(ft2 o
F/ft)
Øs = 1

48
(9): hio for condensing stream: (9):
3/1













De
C
De
K
JHho

hio = (ID/OD)*ho ho = 329.69697 BTU/hr ft2 o
F
hio = (1.12/0.3271)* 329.69697
hio = 1128.89 BTU/hr ft2 o
F
Clean overall coefficient for preheating Up:
Up = (hio*ho) / ( hio + ho)
Up = (1128.89*329.69697) / (1128.89+329.69697)
Up = 255.17283 BTU/hr ft2 o
F
Clean surface required for preheating Ap:
Ap = Qp / Up (∆t)p
Ap = 354900.273/ 255.17283
Ap = 1390.8231 ft2
Vaporization:
(6): At 65oC = 149oF
µ = 0.37
µ = 0.37*2.42 = 0.8954 lb/ft hr
Dis = 0.825 ft

GD
s Re
Res = 12155.428

49
(7): JH = 80
From Appendix A Figure: A-2
(8): At 149oF
K (cµ/k) ^ (1/2) = 0.116Btu/hr (ft2 o
F/ft)
Øs = 1
(9): hio for condensing stream: (9):
3/1













De
C
De
K
JHho

hio=(ID/OD)*ho
hio= (1.12/0.3271)* 112.4848 ho= 112.4848BTU/hr ft2 o
F
hio = 385.15144225BTU/hr ft2 o
F
(10): Clean overall coefficient for vaporization Uv:
Uv = (hio*ho) / (hio + ho)
Uv = (385.15144225*112.4848) / (385.15144225+112.4848)
Uv = 87.058966
(11): Clean surface required for Vaporization Av:
Av = qv/Uv (∆t)v
Av = 1420089.996 / 87.058966
Av = 16311.818 ft2
(12): Total Clean Surface Ac:
Ac = Ap + Av
Ac = 1390.8231 + 16311.818
Ac = 17702.641 ft2

50
(13): Weighted Clean overall coefficient Uc:
UC = ∑UA/Ac
Uc = (354900.273+ 1420089.996) / 17702.641
Uc = 480 Btu/ft2 o
F hr
(14): Design Overall Coefficient:
Surface/lin of tube = 0.3271
Total surface = A = 136*16*0.3271 = 711.77 ft2
Ud = Q(p+v) / A ∆t
Ud = 449 Btu/ft2 o
F hr
Check for max flux:
17702.641 ft2
required for which 16311.818 ft2
used for vaporization. For total surface required
711.77 ft2
will be provide, it can be assume then thus the surface provided for vaporization is
A = (Av/Ac)*Total surface
A = (16311.818/17702.641) * 711.77
A = 655.84881 ft2
The flux is
Q/A = 49944565 / 655.84881 = 76165.5 BTU/hr ft2
(15): Dirt factor:
Rd = (Uc-Ud) / (Uc*Ud)
Rd = 0.001438

51
Pressure Drop
Tube Side, Steam:
(1): For Reynolds tube side = 71135.7, f = 0.00018 ft2
/in2
Specific volume of steam at 14.7 Pisa = 26.8 ft2
/ lb
S = 1/ (26.8*62.5)
S = 0.000597015
(2):  
Dspt
LnfG
P t 10
2
2
1
1022.5 

   
1000597015.00.07251022.5
216087.65E0.00018
102
1


 tP
∆Pt = 6.4422 psi (Allowable 10 psi)
Shell Side, Methanol:
Preheat:
(1): Re = 65848.022f = 0.0015 ft2
/ in2 [fig 29]
(2): Length of preheat zone:
Lp = Lap / Ac
Lp = 16*1390.8231/ 17702.641 = 1.2570537 ft
(3): No. of crosses:
N+1 = 12Lp/B
N+1 = 12*1.2570537 / 5 = 3.01693
S = 0.5, Ds = 23.25/5 = 1.9375, G^2 = 6.3175E+10

52
(4):
 
sDeS
NDsfG
PS s
10
2
1
1022.5
1



1
w
s



15.009.01022.5
3.01693604.1106.3175E0015.0
10


PS
∆Ps = 0.25725 psi
Vaporization:
(1): Res = 12155.4, f = 0.0021 ft2
/in2
(2): Length of vaporization zone:
Lv = BWG – Lp = 16 - 1.2570537 = 14.7429 ft
(3): No. of crosses:
N+1 = 12Lv/B
N+1 = 12*14.7429/5
Methanol Mol.wt = 32.5
Density = 32.5/ (359*(659/492)*(14.7/14.05) = 0.064069453 lb / ft2
S outlet liquid = 0.43
Density outlet liquid = 0.43*62.5 = 26.875 lb/ft2
S outlet mix = (21300.7/62.5) / (21300.7/0.064069453)
S outlet mix = 0.00103
S inlet = 0.5
S mean = (S olute mix + S inlet) / 2

53
S mean = (0.00103 + 0.50) / 2 = 0.2505126
 
sDeS
NDsfG
PS s
10
2
1
1022.5
1



1
w
s



125.09375.11022.5
3831.350.827106.3175E0.0021
10


PS
∆PS = 5.480027 psi
∆PS (total) = 5.73 psi (Allowable 10 psi) [9] [18]

54
Specification Sheet
Identification:
Item: Vaporizer (V-100)
Type: Shell and Tube Heat Exchanger
Function: To Vaporize the Methanol
Heat Duty: 95187252 btu/hr
Shell Side Tube side
Flow rate 21300.8 lb/hr Flow rate 12868.87 lb/hr
Inlet = 298 K, Outlet = 393 K Inlet = 443 K, Outlet = 443 K
Pressure = 2 atm Pressure = 2 atm
Pressure drop 0.38 atm Pressure drop 0.43
Shell dia = 23.25 in OD = 1 in
Baffle Spacing = 4.65 in No. of tubes =136
UD = 449 Btu/ft2
F.hr UC = 480 Btu/ft2
F.hr

55
5.2 Design of Reactor (R-100):
Introduction:
Chemical reactors are basically specific apparatus used for industrial transformations (chemical
reactions) and their design is one of the well-established and developed areas of Chemical
engineering.
The reactor does not generally represent a large financial commitment in the chemical plant, but
it is technically the most important part. And it is the job of chemical engineer to ensure the safe
operation of reactor. The most significant factors which control the behavior of a chemical
reactor are briefly listed below:
a) Physico chemical data on the nature of the chemical reactions.
b) Reaction rates
c) Role of pressure and of temperature on the reaction and reacting species.
d) Diluted state of the species
Types of Reactors:
The general types of chemical reactors which differ in design are enlisted below:
 Fixed-Bed Reactor
 Multi-tubular Reactor
 Slurry Reactor
 Moving Bed Reactor
 Fluidized-Bed Reactor
 Thin or Shallow Bed Reactor
 Dispersion Reactor
 Film Reactor
Fixed Bed Catalytic Reactors:
Introduction:
Fixed-bed catalytic reactors have been characterized as the workhorses of me process industries.
For economical production of large amounts of product, they are usually the first choice,
particularly for gas-phase reactions. Many catalyzed gaseous reactions are amenable to long
catalyst life (1-10 years); and as the time between catalyst changes outs increases, annualized
replacement costs decline dramatically, largely due to savings in shutdown costs. It is not
surprising, therefore, that fixed-bed reactors now dominate the scene in large-scale chemical-
product manufacture.

56
Selection Criteria of Reactor:
For finding best type of reactor we should know following things;
 Conditions in the reactor i.e.; temperature and pressure, reaction time.
 Whether the reaction is exothermic or endothermic or is there any means for removal and
addition of heat.
 Whether reaction carried as batch or continuous flow process.
Equipment Selection:
As our process is continuous we only consider reactors for continuous and heterogeneous
processes as gas, liquid and solid phases are present. Reactors are;
 Fixed and Fluidized bed reactors
 Trickle bed reactors
Why Select Packed Column:
 They primarily used for gas, liquid phase solid catalyzed reaction.
 They have low operating cost
 Continuous operation
 High conversion /unit mass of catalyst
 Can handle Large volume
 For economical production of large amounts of product
T= 393 K
P= 2 atm
O2 = 4444.444 kg/hr
N2 = 14629.63 kg/hr
CH3OH = 9661.836 kg/hr
H2O = 2000 kg/hr
T= 473 K
P= 1.7 atm
O2 = 1903.768 kg/hr
N2 = 14629.63 kg/hr
CH3OH = 793.0435 kg/hr
H2O =4858.21 kg/hr
CH2O =8314.493 kg/hr
CO2 = 21.08 kg/hr
CO = 13.87 kg/hr
H2 = 236.715 kg/hr
R-100
6
18
7
CW=1100 Kg/hr
19
Figure 5.2: Reactor (R-100)

57
Temperature = 473 K
Pressure = 2 atm
Conversion = 0.98
Reaction:
𝐶𝐻3 𝑂𝐻 → 𝐻2 𝐶𝑂 + 𝐻2
𝐶𝐻3 𝑂𝐻 + ½ 𝑂2 → 2 𝐶𝑂 + 𝐻2 𝑂
Design Equation:
𝑊 = 𝐹𝐴𝑜 ∫
𝑑𝑋 𝐴
−𝑟′ 𝐴
𝑋𝐴
0
Where W is the weight of the catalyst Silver, FAo is the flow rate at inlet stream, −rAis the rate of
the reaction.
Net Rate Law:
-r =
( 𝐾1𝐶𝑎𝑅𝑇)
(1+𝐾2𝐶𝑎𝑅𝑇)
Ca = Cao (1-X)
-r=
𝐾1𝑅𝑇𝐶𝑎𝑜(1−𝑋)
1+ 𝐾2𝑅𝑇𝐶𝑎𝑜(1−𝑋)
K1 = exp10.79 – (3810/T)
K1 = 0.00278 kgmol/m3
hr
K2 = exp11.43 – (7040/T)
K2 = 0.01
R = 8.314 kj/kgmol.K

58
Table 5.1: Components Table
Components kg/hr kg/s kgmol/hr kgmol/s Densities
CH3OH 9661.836 2.68 301.93 0.08 15.9
H2O 2000 0.55 111.11 0.03 0.6
O2 4444.444 1.23 138.88 0.03 1.30
N2 14629.63 4.06 522.48 0.14 1.14
Total 30735.91 8.53 1074.41 0.29 4.73
Volumetric flow rate Vo:
= Mass/density
Vo = 1.801879 m3
/s
Cao = Fao/Vo
Cao= 0.046546 kgmol/m3
Table 5.2: Relation between Conversion and Rate Law
Conversion (X)
Rate Law (-ra)
Kgmol/kgcat.hr
Inverse Of Rate Law
(1/-ra) Fao/-ra kgmol/s
0 5.00E-05 19977.33 2899.41
0.1 4.50E-05 22197.00 3221.56
0.2 4.00E-05 24971.57 3624.25
0.3 3.50E-05 28538.89 4141.99
0.4 3.00E-05 33295.31 4832.32
0.5 2.50E-05 39954.30 5798.77
0.6 2.00E-05 49942.79 7248.45
0.7 1.50E-05 66590.26 9664.59
0.8 1.00E-05 99885.22 14496.86
0.9 5.00E-06 199770.07 28993.67
0.98 1.00E-06 998848.91 144968.15

59
Levenspiel Plot:
Plot Between conversion and inverse of rate law:
Figure 5.3: Levenspiel Plot between Conversion and Inverse of Rate Law
Weight of Catalyst:
Simpson two point rule:
∆X= 0.98-0 = 0.98
= 0.98/2 = 0.49
W =
∆X
2
[
FAo
−r′
A(X = 0)
+
FAo
−r′
A(X = 0.98)
]
=0.49*(2899.415037 + 144968.1514)
W = 72455.11 kg
Density of Catalyst:
= 10490 kg/m3
Volume of Catalyst (Vc):
= Weight of catalyst/Density
0
200000
400000
600000
800000
1000000
1200000
0 0.2 0.4 0.6 0.8 1 1.2
InverseOfRateLaw(1/-ra)
Conversion (X)
Levenspiel Plot

60
= 72455.11/10490
Vc = 6.907065 m3
Reactor Volume (Vr):
Volume Of Reactor =
Volume of catalyst
1−Voidage
Vr = Vc/1- φ
φ = 0.6
Vr = 6.907065/(1-0.6)
Vr = 17.26766 m3
Space Time:
Volumetric Flow rate =
Mass flow rate
Density
= 1.801879 m3
/s
Space Time =
Volume of Reactor
𝑉𝑜𝑙𝑢𝑚𝑒𝑡𝑟𝑖𝑐 𝑓𝑙𝑜𝑤 𝑟𝑎𝑡𝑒
=Vr/Vo
= 17.26766/1.801879
= 9.583142 s
For packed bed L/D = 3-4
L/D =3
Diameter of Reactor:
Volume =
𝜋
4
D2
L
Vr -
𝜋
4
D2
*(3D)
Vr -
𝜋
4
3*D3

61
Dia = ((𝑉𝑟∗4)
(𝜋∗3)
)^0.33
= (17.26766*4/3.14*3)^0.33
Dia of Reactor = 1.929879 m
Length of Reactor:
L = 3D
L = 3*1.929879
L = 5.789637 m
Number of Tubes:
Number of Tubes = Volume of Catalyst/Volume of Tube
=Volume of Catalyst/(
𝜋
4
*D2
*L)
Volume of Catalyst = 242.7636 ft3
Dia of Tube = 0.3937
Length Of Tube = 16 ft
= 242.7636/(3.14/4)*(0.3937)2
*16
Nt = 777
Pressure Drop:
• Using Ergon equation
Ergun’s equation (Unit Operation in Chemical Engineering by McCabe Smith 7th Edition).
Cross sectional area = 2.9236 m2
2 2
o o
2 2 3 3
s p s p
Δp 150V μ (1 ε) 1.75ρV 1 ε
= +
L D ε D ε 
   
  
      

62
Volumetric flow rate = mass flow rate / density
Volumetric flow rate = 1.801878906 m3/s
Superficial velocity = volumetric flow rate / cross sectional area = 0.6163 m/s
Average Density of feed = 4.73825 kg/m3
Average viscosity of feed = 0.00047035 kg/m sec
Dp = 0.004 m
L = 5.789637 m
Ɛ = 0.5
Putting values in Pressure Drop equation
∆P/L = 6299.08
∆P = 36469.42 pas
∆P = 36469.42/105
∆P = 0.32 atm [20]

63
Specification Sheet
Identification:
Item: Reactor (R-100)
Type: Packed Bed Catalytic Reactor
Function: To Produce CH2O From CH3OH using Silver Catalyst
Operating Pressure 2 atm
Operating Temperature 473 K
Space Time 9.58 s
Volume of Reactor (Vr) 17.26 m3
Volume of Catalyst (Vc) 6.90 m3
Weight of Catalyst 72.45 ton
Dia of Reactor (D) 1.92 m
Length of Reactor (L) 5.78 m
No. of Tubes 777
Pressure Drop (ΔP) 0.32 atm

64
5.3 Design of Absorber (A-100):
Absorption:
Absorption is the phenomena of separation of solute gases from gaseous mixtures of non-
condensable by transfer into a liquid solvent. This recovery is attained by contacting the gas
stream with a liquid that offers specific or selective solubility for the solute gas or gases to be
recovered. It is the second main operation of chemical engineering based on mass transfer.
The Purpose of this Absorber is to absorb methanol and formaldehyde from the product stream of
gas using water natural solvent. And removing the tail gases from the top of absorber.
Types of Absorption
1) Physical Absorption
2) Chemical Absorption
Physical Absorption
In it mass transfer takes place purely by diffusion and is governed by the physical equilibria.
Chemical Absorption
In this type of absorption a chemical reaction occurs as soon as a certain component comes in
contact with the absorbing liquid.
Types of Absorber:
1) Packed Columns
2) Plate Columns
Packed Column Selection
Packing Selection
It is the most important factor of the system. The packing provides adequate area for intimate
contact between phases. The efficiency of packing with respect to both HTU and flow capacity
determines to an important extent the overall size of the tower. The economics of the installation
are therefore tied up by the packing choice.
The principal requirements of a tower packing are:
1) It must be chemically inert to the fluids in the tower.
2) It must be strong without excessive weight.

65
3) It must contain sufficient passages for both streams without extreme liquid holdup or
pressure drop.
4) It must offer good contact between liquid and gas.
5) It must be reasonable in cost.
The packing is the heart of the performance of the absorber. Its proper selection involves an
understanding of packing operational features and the effects on performance of the points of
major physical difference between several types. The types and corresponding merits and
demerits are given below.
 Rashing Rings
 Berl Saddles
 Intalox Saddles
 Pall Rings
For the absorption packing selected in this case are Pall Rings because of the following features.
Merits of Pall Rings:
1) One of the most efficient packing
2) Very little tendency or ability to nest and block areas of bed
3) Higher flooding limits and lower pressure drop than Rashing rings or berl saddles
4) Lower HTU values for most common systems
5) High Loading & Throughput
6) Easily Wettable
7) High Resistance of Fouling
8) High Temperature Applications
9) Good Liquid and Gas Distribution
10) High Mass Transfer Efficiency
Designing steps of Absorber:
 Selection of Column
 Selection of packing and material
 Selection of packing and material
 Calculating the size of packing
 Calculate Flow Factor
 Calculate K4& Mass Velocity
 Calculate the Area of Column
 Calculating the diameter of column
 Determining the height of transfer unit (HOG)
 Determining the number of transfer units (NOG)

66
 Determining the height of the column
 Calculating the operating velocity
 Calculating the flooding velocity
 Determining the pressure drop across the column
Process
Water
T= 303 K
P= 1.8 atm
H2O = 9170 kg/hr
T= 338
P= 1.5 atm
CH3OH = 793.0435 kg/hr
H2O =4858.21 kg/hr
CH2O =8314.493 kg/hr
Tail Gas
AT-100
T= 473 K
P= 1.7 atm
O2 = 1903.768 kg/hr
N2 = 14629.63 kg/hr
CH3OH = 793.0435 kg/hr
H2O =4858.21 kg/hr
CH2O =8314.493 kg/hr
CO2 = 21.08 kg/hr
CO = 13.87 kg/hr
H2 = 236.715 kg/hr
T= 438 K
P= 1.5 atm
O2 = 1903.768 kg/hr
N2 = 14629.63 kg/hr
CO2 = 21.08 kg/hr
CO = 13.87 kg/hr
H2 = 236.715 kg/hr
7
8 10
9
Figure 5.4: Absorber A-100
G = Gas flow rate = 30735.90982 kg/hr
PG = Pressure of gases = 1.75kg/cm2
TG = Temperature of gases = 2000
C
ʃG = Density of Gas = 3.2 kg/m3
µG = viscosity of gas =0.0000125 N.s/m2

67
L = Solvent flow rate = 9107.536232 kg/hr
PL = Pressure of solvent = 1.85 kg/cm2
TL = Temperature of solvent = 300
C
ʃL = Density of Water = 1000 kg/m3
µL = Viscosity of Water = 0.00091 N.s/m2
POp = Operating pressure = 1.75 kg/cm2
Flow Factor FLV
FLV =
𝐿
𝐺
√
ʃ 𝐺
ʃ 𝐿
FLV = 0.020762154
Design for pressure drop of 42 mmH2O/m of packing. Therefore
From Appendix B Figure B-1
With respect to FLV the value of K4 from graph 11.44 is = 2.0
K4 at flooding from graph 11.44 is = 6.0
Percentage flooding =√
𝐾4
𝐾4 𝑎𝑡 𝑓𝑙𝑜𝑜𝑑𝑖𝑛𝑔
Percentage Flooding = 59.56833972%
Calculation of Diameter of column:
Packing selected is Metal Pall Rings.
From Appendix B Table B-1
Packing factor of Metal Pall Rings is = Fp = 66 m-1
 
 
g L g
0.
0 1
4
.
L L
5
ρ ρ -ρ
Fp
k * *
*
13 /ρ.1 µ* *
G
 
 
 
 

68
G* = 4.0432 kg/m2.s
Column area required = G/ G*
G = Gas flow rate = 8.53 kg/s
Column area required = 8.53/4.0432
Column area required = 2.1116 m2
Diameter = √
4
π
∗ Column area required
Diameter = 1.640 m
Onda’s Method
Calculation of Height transfer Unit:
aw = Effective interfacial area of packing per unit volume m2
/m3
Lw = Liquid mass velocity = 1.1980 kg/m2
.s
σL = surface tension of Water = 0.072 N/m
σc = surface tension for particular material of packing = 0.0075 N/m
a = actual area of packing per unit volume = 102 m2
/m3
g = 9.81 m/s2
aw/a = 0.10182





































 2.0205.0
2
21.075.0
45.1exp1
a
L
g
aL
a
L
a
a
LL
w
L
w
L
w
l
cw



69
aw = 0.10182*a
aw = 0.10182*102
aw = 10.3866 m2
/m3
Calculation of liquid film mass transfer coefficient:
KL = liquid film coefficient m/s
dp = packing size = 51 mm = 0.051 m
DL= Diffusivity of liquid = 2.82*10-5
m2
/s
/m3
= 10.3866m2
/m3
Lw = Liquid mass velocity = 1.1980 kg/m2
.s
/m3
g = 9.81 m/s2
KL = 0.000463 m/s
Calculation of gas film mass transfer coefficient:
KG = Gas film coefficient, kmol/m2
s.bar
K5 = 5.23 (Packing size above 15 mm)
Vw = Gas mass velocity = 4.0432 kg/m2
.s
TG = Temperature of gases = 2000
C
R = 0.08314 bar.m3/kmol.K
  4.0
2
1
3
2
3
1
0051.0 p
LL
L
Lw
w
L
L ad
Da
L
g
K L


























70
µG = Viscosity of gas = 0.0000125 N.s/m2
DG= µG/ʃG
DG = 3.906*10-6
m2
/s
dp = packing size = 51 mm = 0.051 m
/m3
KG = 0.000552 kmol/m2
.s.bar
Gas Film Transfer Unit Height:
Gm = Gas mass velocity = 0.13042 kgmol/m2
.s
PG = Pressure of gases = 1.75 kg/cm2
KG = Gas film coefficient = 0.000552 kmol/m2
.s.bar
/m3
= 10.3866m2
/m3
HG = Gas film transfer unit height, m
HG = 5.4996 m
Liquid film transfer unit height:
Lm = Liquid mass velocity = 0.0665 kgmol/m2
.s
Ct = Total concentration, kmol/m3 =ʃL/Molecular weight of solvent
Ct = 1000/18
Ct = 55.55 kmol/m3
  2
3
1
7.0
5

















 p
gg
g
g
w
g
gG
ad
Da
V
K
aD
RTK



P
w
a
G
K
m
G
G
H 

71
KL = Liquid film coefficient = 0.000463m/s
/m3
= 10.3866m2
/m3
HL = Liquid Film Transfer Unit Height, m
HL = 0.2488 m
Calculation of Height of Transfer Unit:
HG = Gas film transfer unit height = 5.285 m
Colburn has suggested the economic value of mGm/Lm from 0.7 to 0.8
So we selected the value of mGm/Lm = 0.75
HL = Liquid Film Transfer Unit Height = 0.2488 m
HOG = 5.011 m
Calculation of Number of Transfer Units:
Equation for equilibrium curve:
Y1= Mole fraction of CH3OH and CH2O in entering gas stream = 0.2375
Y2 = Mole fraction of CH3OH and CH2O in Leaving gas stream = 0.02375
Y1/Y2 = 0.2375/0.02375 = 10
mGm/Lm = 0.75
From Appendix B Figure B-2
NOG is obtained From Appendix B Figure 5.10 using Y1/Y2 and mGm/Lm
NOG = 5
LH
mL
mmG
GHoGH 
t
C
w
a
L
K
m
L
L
H 

72
Calculation of height of tower:
Total height of packing = Z = NOG × HOG
Z = 5*5.011
Z = 25m
Allowances for liquid distribution = 1 m
Allowances for liquid Collection = 1 m
Total Height = 29+1+1
Total Height = 27 m
Calculation of operating velocity:
FLV =
𝐿
𝐺
√
ʃ 𝐺
ʃ 𝐿
FLV = 0.0207
With respect to FLV the value of K4 from graph 11.44 is = 2.0
Packing factor of metal pall rings is = Fp = 66 m-1
 
 
g L g
0.
0 1
4
.
L L
5
ρ ρ -ρ
Fp
k * *
*
13 /ρ.1 µ* *
G
 
 
 
 

73
G = 4.043 kg/s
Calculation of flooding velocity:
FLV =
𝐿
𝐺
√
ʃ 𝐺
ʃ 𝐿
FLV = 0.0207
With respect to FLV the value of K4 from graph 11.44 at flooding is = 6.0
Packing factor of metal pall rings is = Fp = 66 m-1
 
 
g L g
0.
0 1
4
.
L L
5
ρ ρ -ρ
Fp
k * *
*
13 /ρ.1 µ* *
G
 
 
 
 
G = 6.7875 kg/s
Operating velocity must be 50-90% of the flooding McCabe & Smith
Calculation of wetting rate:
Volumetric liquid flow rate = 0.00252 m3
/s
Volumetric liquid flow rate per unit cross sectional area = 0.001198 m3
/m2
.s
a = surface area of packing per unit volume = 102 m2
/m3

74
Wetting rate =
Liquid Volumetric flow rate per unit cross−sectional area
Specific area of packing per unit volume
Wetting rate = 1.97183E-05 m2
/s
Calculation of Pressure Drop at Flooding
(McCabe & Smith (5th Ed.)
Pressure drop at flooding is given by relation.
ΔPflooding = 0.115Fp
0.7
Fp =packing factor for 2-inch metal pall rings = 66 m-1
Fp =packing factor for 2-inch metal pall rings = 20.1219 ft-1
ΔPflooding = 0.115*660.7
ΔPflooding = 2.159 inH2O/m of Packing
ΔPflooding = 54.422 mmH2O/m of Packing
ΔPflooding = 0.00526 atmH2O/m of Packing
Calculation of Total Pressure Drop:
Gy = Gas mass velocity = 4.0432 kg/m2
.s
Gx = Liquid mass velocity = 1.1980 kg/m2
.s
𝐺𝑥
𝐺 𝑦
√
ʃ 𝑦
(ʃ 𝑥 − ʃ 𝑦)
= 0.016789
G = Gas flow rate = 8.53 kg/s
gc = 32
Fp =packing factor for 2-inch metal pall rings = 66 m-1

75
𝐺2
∗ 𝐹𝑝 ∗ µ0.1
ʃ 𝑔(ʃ𝑙 − ʃ 𝑔)𝑔𝑐
= 0.07633
With respect to
𝐺 𝑥
𝐺 𝑦
√
ʃ 𝑦
(ʃ 𝑥−ʃ 𝑦)
and
𝐺2∗𝐹𝑝∗µ0.1
ʃ 𝑔(ʃ 𝑙−ʃ 𝑔)𝑔 𝑐
pressure drop from the graph will be From Appendix B
Figure B-3
ΔP = 0.72 in.H2O/ft of packing
ΔP = 1.764mmH2O/ft of packing
ΔP = 5.785 mmH2O/m of packing
Total Height of packing = 25 m
Total ΔP = ΔP*Total Height of packing
Total ΔP = 5.785*25
Total ΔP = 144.791 mmH2O
Total ΔP = 0.2 atm [17]

76
Specification Sheet
Identification
Item: Absorber (A-100)
Type: Packed Column
Packing: Metal Pall Rings
Function: To Absorb CH3OH & CH2O Gas From Product Stream
Operating Pressure 1.7 atm
Dia of Absorber 1.64 m
Column Height 27 m
Area 2.11 m2
Height of Transfer Unit 5.01 m
No. of Transfer Unit 5
Pressure Drop (ΔP) 0.2 atm

77
5.4 Design of Distillation Column (D-100):
The purpose of following distillation design is to recover unreacted methanol from the solution of
water and formaldehyde. Methanol is recovered from the top and mixture of water and
formaldehyde is received from the bottom of the column.
Types of distillation:
There two major types on the basis of operation:
 Batch distillation
 Continuous distillation
Choice of Distillation Column:
Here continuous distillation is selected to get continuous and large quantity of product in a short
period. Operating pressure is one atm, moderated temperature. Sieve plates are used for
economical separation.
Table 5.3: Choice of Distillation
Comparing
Parameters
Valve Plate
Bubble Cap
Plate
Sieve Plate
Cost Moderate High Low
Capacity Low Low High
Pressure Drop Moderate High Low
Fouling High High Low
Designing steps:
Steps for design of Distillation Column are following[36].
 Bubble point and Dew point calculation
 Minimum Reflux Ratio Rm.
 Optimum reflux ratio.
 Theoretical number of stages.
 Actual number of stages.
 Diameter of the column.
 Weeping point.
 Residence time.

78
 Pressure drop.
 The height of the column.
T= 350 K
CH3OH = 785.11304 kg/hr
H2O = 139.65797 kg/hr
CH2O =83.144928 kg/hr
T= 353 K
CH3OH = 7.90435 kg/hr
H2O = 9016.461 kg/hr
CH2O =8231.348 kg/hr
T= 338 K
P= 1.8 atm
CH3OH = 793.0435 kg/hr
H2O =4858.21 kg/hr
CH2O =8314.493 kg/hr
T= 350 K
P = 1.66 atm
T= 358 K
D-100
11
12
14
13
20
21
22
23
9
CW= 1425 kg/hr
T= 355 K
P = 1.66 atm
Figure 5.5: Distillation Tower D-100
Compositions
Table 5.4: Composition of Components
Component Feed(fr) Distillate(fr) Bottom(fr)
Feed
Kg/hr
Distillate
Kg/hr
Bottom
Kg/hr
CH3OH 0.03 0.78 0.00 793.04 785.11 7.93
CH2O 0.36 0.08 0.37 8314.49 83.14 8231.35
H2O 0.61 0.14 0.63 13965.80 139.66 13826.14
Total 1.00 1.00 1.00 23073.33 1007.92 22065.42

79
Flash calculations:
Antoine Equation
log
B
p A
T C
 

Antoine Coefficients
Table 5.5: Antoine Coefficients
Component A B C
CH3OH 4.18 959.43 -21.76
CH2O 4.55 957.24 -98.00
H2O 3.56 643.75 -198.04
Using Antoine equation find the partial vapor pressure (pi) of each component
Table 5.6: Partial Pressure Pi
Component A B C log Pi Pi
CH3OH 4.18 959.43 -21.76 1.15 14.0007888
CH2O 4.55 957.24 -98.00 0.56 3.64
H2O 3.56 643.75 -198.04 -1.04 0.09
Table 5.7: Partial Pressure of Components
Components Pi Ki Xi ki.xf yi
CH3OH 14.00 13.82 0.01 0.47 0.12
CH2O 3.64 3.60 0.23 1.30 0.81
H2O 0.09 0.09 0.77 0.05 0.07
Total - - 1.00 1.83 1.00

80
Sample Calculations for heavy key
Z L V 
vap
i
Total
p
K
p

ki = 3.64/1.6
ki = 3.60
1 ( 1)
i i
i
z k
y
v k


  
yi = 0.81
1 ( 1)
i
i
i
z
x
v k

  
xi = 0.23
Bubble Point Calculation for feed:
Use flash calculation method to find fraction of liquid and vapor of each component in feed
P = 1.8 atm
Table 5.8: Bubble Point Calculation for Feed
Components Pi Ki Xi ki.xf Yi Α
CH3OH (LK) 14 13.82 0.01 0.47 0.12 3.84
CH2O (HK) 3.64 3.6 0.23 1.3 0.81 1
H2O 0.09 0.09 0.77 0.05 0.07 0.03
Total - - 1 1.83 1 -
Sample Calculations for Light key
i
i
c
k
k
 

81
αi = 3.84
i i
i
i i
x
y
x



yi = 0.12
1
c
i i
k
x


kc = 3.59
Bubble point of feed is 338 K at 1.8 atm
Dew Point Calculation of Top
T = 350 K
P = 1.8 atm
Table 5.9: Dew Point Calculation of Top
Components Α Ki Xd Σxi=ΣXd/Ki
CH3OH 3.84 13.82 0.78 0.06
CH2O 1.00 3.60 0.08 0.02
H2O 0.03 0.09 0.14 1.54
Total - - - 1.62
So Dew Point is 350 K at 1.8 atm
Bubble Point Calculation of Bottom:
Table 5.10: Bubble Point Calculation of Bottom
Components Ki xb Ki..x b
CH3OH 17.77 0.00 0.01
CH2O 2.31 0.37 0.86
H2O 0.21 0.63 0.13
Total - - 1.00
So the bubble point is 355 K at 1.8 atm [8]

82
Underwood Correlation
At average temp of dew point and bubble point temperature
Tavg=
76.12+81.717
2
= 78.83 Co
, 351 K
Sample Calculations for Light Key
log
B
p A
T C
 

P = 1.8 atm
vap
i
Total
p
K
p

Ki = 17.77
i
i
c
k
k
 
αi = 3.21
by trail ϴ = 2.71
Table 5.11: Underwood Equation
Components P Ki Α Xd ϴ Rm+1=Σ(αi*Xd)/(αi-ϴ)
CH3OH 1.01 17.77 3.21 0.78 2.71 4.98
CH2O 1.01 5.53 1.00 0.08 2.71 -0.048
H2O 1.01 0.21 0.04 0.14 2.71 -0.002
Total - - 4.25 1.00 - 4.93
As feed is at boiling point so
𝛼𝑖−𝑥𝑓
𝛼𝑖− θ
=
3.21−0.003
3.21−2.71
=2.707

83
1 i f
i
x
q
 
  
 
As feed is at boiling point so
1q 
1 0q 
Calculation of minimum reflux ratio
1 i d
m
i
x
R
 
 
 
Rm = 3.93
R = 3.93(1.2) = 4.72
Ideal no of stages:
Fenskey equation
min
log
1
log
lk hk
hk lkd b
lk
x x
x x
N
   
   
   
 

Nmin +1 = 7.88
Nmin = 6.88
To estimate ideal number of stages use Eduljee relationship
𝑁 − 19.86
𝑁 + 1
= 0.75 [1 − (
𝑅 − 𝑅 𝑚𝑖𝑛
𝑅 + 1
)
0.566
]
𝑁 − 19.86
𝑁 + 1
= 0.75 [1 − (
4.72 − 3.93
4.72 + 1
)
0.566
]
N = 14.87
Sample calculation for heavy key

84
Use Antoine equation to find Vapor pressure
log
B
p A
T C
 

P = 1.6 bar, 1.62 atm
Z L V 
vap
i
Total
p
K
p

Ki = 0.16
1 ( 1)
i
i
i
z
x
v k

  
xi = 0.96
l i ix  
ρi = 815.00 kg/m3
l i ix  
𝜌𝑙 = 815
𝑘𝑔
𝑚3
v i iy  
𝜇 𝑎𝑣𝑔 = 0.03
𝑚𝑁𝑠
𝑚2
Column efficiency:
To estimate column Efficiency use O’Connell’s correlation
 51 32.5logo avg avgE    
Eo = 0.89%

85
To estimate feed point location use Kirk bride correlation
 
 
2
log 0.206
lkhkE B
S lk hk DF
xxN B
N x D x
                        
log (
𝑁𝐸
𝑁𝑠
) = −0.53
(
𝑁𝐸
𝑁𝑠
) = 0.29
E sN N N 
𝑁𝐸 = 0.29𝑁𝑆
𝑁 = 1.29 𝑁𝑆
𝑁𝑆 = 0.53
Nreal = Eo/ Ns =15.78
Feed plate= 12.27
So Feed point location is 12th
from bottom.
Flooding Velocity:
w v
lv
w l
L
F
V
  
  
 
From Appendix C Figure C-1
Flv = 0.66
At 0.45 m spacing
0.2
1
0.02
l v
f
v
U K
    
  
  
Uf = 0.01 m/s

86
Take Uop 75% of Uf
𝑈 𝑜𝑝 = 𝑈𝑓 × 0.75
𝑈 𝑜𝑝 = 0.0075
𝑚
𝑠
w
v
v
V
Q 

𝑄 𝑣 = 0.003
𝑚3
𝑠
Uf = 0.01m/s
Take Uop 70% of Uf
Uop = 0.01 m/s
Volumetric flowrate:
Assumptions
 Plate Spacing =0.45mm
 Plate thickness= 3.00mm
 Hw= 40.00mm
 Dh= 3.500mm
Flow rate
w
v
v
V
Q 

𝑄 𝑣 = 0.003
𝑚3
𝑠
Net area required:
v
n
op
Q
A
U

𝐴 𝑛 = 0.44 𝑚2

87
Column Cross sectional Area:
n c dA A A 
0.12d cA A
0.88n cA A
88.0
n
c
A
A 
𝐴 𝑐 = 0.50 𝑚2
Diameter:

Ac
Dc
*4

𝐷𝑐 = 0.80 𝑚
Down comer Area:
0.12d cA A
𝐴 𝑑 = 0.06 𝑚2
Active Area:
2a c dA A A 
𝐴 𝑐 = 0.38𝑚2
Hole Area:
Let’s by trial its 1.2% of Aa
𝐴ℎ = 0.012 × 𝐴 𝑎
𝐴ℎ = 0.005 𝑚2

88
Weir height = hw = 40mm
Plate thickness = 3mm
Hole diameter = dh = 3.5mm
Weir Length:
100 12d
c
A
A
 
  
 
0.75w
c
l
D

𝑙 𝑤 = 0.6 𝑚
Weir Liquid Crest:
2/3
750 w
ow
w w
L
h
l
 
  
  
ℎ 𝑜𝑤 = 14.35 𝑚𝑚
ℎ 𝑜𝑤 + ℎ 𝑤 = 14.3 + 40
ℎ 𝑜𝑤 + ℎ 𝑤 = 54.3𝑚𝑚
Weeping point:
K2 = 29.7
 2
0.5
0.9(25.4 )h
h
v
K d
U
 


𝑈ℎ = 0.44
𝑚
𝑠

89
0.7vap w
act
v h
V
U
A
 
  
  
𝑈 𝑎𝑐𝑡
𝑣𝑎𝑝
= 0.47
𝑚
𝑠
𝐼 𝑝 = 2.8 × 4
𝐼 𝑝 = 9.8 𝑚𝑚
Dry tray Pressure drop:
2
0.9
h h
p p
dA
A l
 
   
  
𝐴ℎ
𝐴 𝑝
= 0.9 × [
3.5
11.20
]
0.114
h
p
A
A

𝑃𝑙𝑎𝑡𝑒 𝑇ℎ𝑖𝑐𝑘𝑛𝑒𝑠𝑠
𝑑ℎ
=
3
3.5
𝑃𝑙𝑎𝑡𝑒 𝑇ℎ𝑖𝑐𝑘𝑛𝑒𝑠𝑠
𝑑ℎ
= 0.86
Co = 0.81
2
51
h v
d
o L
U
h
C
 
    
ℎ 𝑑 = 10.96 𝑚𝑚 of liquid
Residual head:
3
12.5*10
r
L
h 


90
ℎ 𝑟 = 15.39 𝑚𝑚
Plate Pressure Drop:
3
9.81 10t t lP h
   
𝛥𝑃𝑡 = 642.87 𝑝𝑎
Area of Single Hole =
2
4
hd
Area of single hole= 0.000010 m2
No. of holes = 474.97
Total Drop:
 t d w ow rh h h h h   
ℎ 𝑡 = 80.70 𝑚m
Pressure Drop:
ΔP = 9.8 * 10-3
h1ρ
=0.14 atm [10]

91
Specification Sheet
Identification
Item: Distillation column (D-100)
Type: Multi component Distillation column
Function: To recover methanol from water and formaldehyde
Operating Pressure 1.82 atm Operating temperature 351 K
No of stages 16 Feed plate location 12.27 bottom
Plate Type Sieve Plate dh 0.0035 m
Plate Spacing 0.45 m ΔP 0.14 atm
Plate thickness 0.0035 m tr 8.09 s
Diameter of Column 0.8 m Hole Area 0.005 m
2
Height of column 7.64 m No of holes 474.97

92
5.5 Design of Heat Exchanger (E-100):
Heat Exchanger:
Heat transfer is a much important and most of an applied process in the area of chemical and
petrochemical plants. The general economics of a specific plant operation most of the time are
maintained by efficient utilization and recovery of heat or cold fluid. The mostly used word
exchanger is implemented to all the kinds of equipment which exchange the heat but mostly used
specifically to represent the equipment in which the heat is exchanged between two process
streams.
Heat exchanger is usually a part of equipment which continuously transfers the heat from one
media to another in order to carry process energy, without mixing the process fluids. Heat
exchangers are used here to pre-heat the feed for the distillation column.
Selection of heat exchanger type:
The “Selection Guide to Heat Exchanger Types” provides a view of different types of heat
exchanger. We will choose the best one to fulfill our requirements.
Table 5.12: Heat Exchanger Type
Type Significant feature
Applications best
suited
Limitations
Approximate
relative cost in
carbon-steel
construction
Fixed tube
sheet
Both tube sheets fixed
to shell.
Condensers; liquid-
liquid; gas-gas; gas-
liquid; cooling and
heating, horizontal or
vertical and reboilling.
Temperature
difference at extremes
of about 200 o
F Due to
differential expansion.
1.0
Floating
head or tube
sheet
(removable
and non-
removable
bundles)
One tube sheet
“floats” in shell or
with shell, tube
bundle may or may
not be removable
from shell, but back
cover can be removed
to expose tube ends.
High temperature
differentials, above
about 200 o
F
extremes; dirty fluids
requiring cleaning of
inside as well as
outside of shell,
horizontal or vertical.
Internal gaskets offer
danger of leaking.
Corrosiveness of fluids
on shell-side floating
parts. Usually confined
to horizontal units.
1.28

93
We choose shell and tube exchanger to fulfill above mention duty.
U-tube;
U-Bundle
Only one tube sheet
required. Tubes bent
in U-shape. Bundle is
removable.
High temperature
differentials, which
might require
provision for
expansion in fixed
tube units. Easily
cleaned conditions on
both tube and shell
side.
Bends must be
carefully made, or
mechanical damage
and danger of rupture
can result. Tube side
velocities can cause
erosion of inside of
bends. Fluid should be
free of suspended
particles.
0.9-1.1
Double pipe
Each tube has own
shell forming annular
space for shell side
fluid. Usually use
externally finned tube.
Relatively small
transfer area service,
or in banks for larger
applications.
Especially suited for
high pressures in tube
(greater than 400
psig).
Services suitable for
finned tube. Piping-up
a large number often
requires cost and
space.
0.8-1.4
Pipe coil
Pipe coil for
submersion in coil-
box of water or
sprayed with water is
simplest type of
exchanger.
Condensing, or
relatively low heat
loads on sensible
transfer.
Transfer coefficient is
low, requires relatively
large space if heat load
is high.
0.5-0.7

94
T= 303 K
P = 1.45 atm
CH3OH = 7.90435 kg/hr
H2O = 9016.461 kg/hr
CH2O =8231.348 kg/hr
T= 353 K
P = 1.66 atm
CH3OH = 7.90435 kg/hr
H2O = 9016.461 kg/hr
CH2O =8231.348 kg/hr
T= 298 K
T= 323 K
E-100
24
26
25
27
Figure 5.6: Heat Exchanger E-100
Inlet temperature of solution = T1 = 176o
F
Outlet temperature of solution= T2 = 86°F
Inlet temperature of cooling water = t1 =77 °
F
Outlet temperature of cooling water = t2 = 122 °
F
Required data for the process fluid
Mass flow rate of solution =38042.32 lb/ hr
Specific heat capacity of solution (Weighted) = Cp = 0.44 Btu/lb
Thermal conductivity of solution = K= 0.99 Btu/ft.F
Viscosity of solution = µ =1.640 lb/ft.h
Heat taken by solution
TmCQ p 
Q = 1506475.8 Btu/hr

95
Mass flow rate of water
Mass flow of cooling water = m= 47985.59 lb/hr
LMTD
LMTD =
(𝑇1−𝑡2)−(𝑇2−𝑡1)
𝐿𝑛[
(𝑇1−𝑡2)
𝑇2−𝑡1
]
= 25.15 o
F
Since cooling water is condensing medium therefore R = 2, S=0.45 and FT =0.62 so
tTm 
=15.59 o
F
Assumed calculations
From Appendix D Table D-1
Value of UD assumed UD = 250Btu/ft2
.F
Heat transfer area
tU
Q
A
D

A= 389.4 ft2
From Appenndix D Table D-2
Tube O.D. = 0.75 ft
From Appendix D Table D-3
BWG=16
Tube pitch=PT = 1 in square
No.of passes=Nt=2

96
Internal area per unit length of tube =at =0.042 ft2
No. of tubes required are
=
𝐴
(𝑎𝑡)∗(𝐿−(𝑡𝑢𝑏𝑒 𝑠ℎ𝑒𝑒𝑡 𝑡ℎ𝑖𝑐𝑘𝑛𝑒𝑠𝑠)
= 123 tubes
From nearest tube count Table
For 124 tubes shell I.D. for two pass = 15.25 in
Shell Side Calculations:
Shell side data
Shell outer diameter =ID =15.25 in
Baffle spacing on shell side =B =3.65 in [Eq. (11.4)]
Tube pitch=PT= 3/4in square= 1 in square
Tube OD =0.75 in
Clearance between tubes = C/
= PT -O.D=1-0.75 =0.25 in
Equivalent diameter of shell for square pitch with clearance
= De = 0.0792 ft
Flow area
T
s
P
BIDxC
a
'

a s =0.0926 ft2
Mass velocity
s
s
a
W
G 

97
G s = 410800 lb/ft2
hr
Reynold’s No

seGD
Re
Re =19800
From Appendix D Figure D-1
JH Factor
jH = 90
Shell side coefficients
3
1







k
C
D
k
J
h p
e
H
o
o


=1012.5 Btu/ft². F
For coefficient correction assume it is unity so
ho = 1012.5 Btu/ft2
.F
Tube Side Calculations:
Data required for cooling water in tubes.
Inside Dia of tube =0.620 in
Viscosity of Cooling water=0.79 lb/ft.hr
Thermal conductivity of Cooling water =0.346

98
Flow area
Internal area per unit length of tube =at =0.302in²
No of passes= 2
at =
𝑁𝑡∗𝑎𝑡
𝑛
= 0.0650 ft²
Mass velocity tube side
t
t
a
W
G 
G t= 738200.6 lb/ft2
hr
Reynolds No

tGD
Re
Re =19900
JH Factor
JH = 80
For cooling water, hi=hio =871.3 Btu/ft2
.F
Clean overall coefficient
Uc =
ho∗hio
ho+hio
Uc= 420.8 Btu/ft2
.°F
Ud = Q/A*ΔT
Ud = 248.1Btu/ft2 o
F hr

99
Dirt factor:
Rd = (Uc-Ud)/(Uc*Ud)
Rd = 0.00165
Pressure Drop (Shell Side):
Friction factor for shell side = f = 0.0018ft2
/in2
Diameter of the shell =Ds =1.104 ft
No. of crosses, N+1 = 12L/B = 54.8
se
ss
s
sDx
NDfG
P
11
2
1054.2
)1( 

ΔPs=6.17 psi
Pressure Drop(Tube Side):
Friction factor for tube side = f = 0.00025 ft2/in2
t
t
s
Dsx
LnfG
P
11
2
1054.22
1

ΔPs= 3.30 psi
Both pressure drops are in allowable limit
Result:
The unit has been designed satisfactorily [18]

100
Specification Sheet
Identification:
Item: Cooler (E-100)
Type: Shell and Tube Heat Exchanger
Function: To reduce the temperature of Product Formaldehyde
Heat Duty = 1506475.8 btu/hr
Shell Side Tube Side
Fluid Handled = Mixture of feed Utility = Cooling Water
Flow rate = 38042.32 lb/hr Flow rate = 47985.5 lb/hr
Baffle Spacing = 3.5 in No. of Tubes = 124
Shell Dia = 15.25 OD = 0.75 in
Inlet = 350 K, Oulet = 303 K Intet = 307 K, Outlet =320 K
Pressure Drop (ΔP) = 0.41 atm Pressure Drop (ΔP) = 0.22 atm

Chapter No. 6 Mechanical Design
101
Chapter No. 6
6 Mechanical Design

Chapter No.6 Mechanical Design
102
6.1 Max Allowable Pressure:
Hydrostatic Pressure = ρgh
= 0.000268 N/mm2
Pressure in Reactor = 2.02 bar = 0.202N/mm2
Max Allowable Pressure = Pi = 0.202 * 1.1 + 0.000268 N/mm2
= 0.222 N/mm2
6.2 Max Allowable Temperature:
Max Allowable Temperature = 1.1 * T
= 1.1 * 200
= 220℃
6.3 Wall Thickness:
Material = Carbon Steel
Diameter = Di = 1929.87 mm
Height = 5780 mm
Corrosion Allowance = Cc = 2mm
Stress Factor = f = 101 N/mm2
Joint Efficiency = J = 1
𝑒 =
𝑃𝑖 𝐷𝑖
2𝑓𝐽 − 𝑃𝑖
𝑒 =
0.222 ∗ 1929.87
2 ∗ 1 ∗ 101 − 0.22
𝑒 = 2.12 𝑚𝑚
With Corrosion Allowance

103
𝑒 = 2.12 + 2
𝑒 = 4.12 𝑚𝑚
6.4 Torispherical Head:
Crown Radius = Rc = 1929.87 mm
Knuckle Radius = Rk = 0.06 Rc
𝐶𝑠 =
1
4
(3 + √
𝑅 𝑐
𝑅 𝑘
)
𝐶𝑠 = 1.77
𝑒 =
𝑃𝑖 𝑅 𝑐 𝐶𝑠
2𝑓𝐽 − 𝑃𝑖(𝐶𝑠 − 0.2)
𝑒 = 3.75 𝑚𝑚
With Corrosion Allowance
𝑒 = 3.75 + 2
𝑒 = 5.75 𝑚𝑚
6.5 Vessel Supports:
The method used to support a vessel will depend on the size, shape, and weight of the vessel; the
design temperature and pressure and the vessel location and arrangement. The types of support
are
1. Saddle support (for horizontal vessels)
2. Brackets support (for vertical vessels)
3. Skirt support (for vertical vessels, particularly where the length is high and effect of wind is
prominent)
For reactor, we use “Bracket supports
6.6 Circumferential Stress:
σh =
𝑃𝑖 𝐷𝑖
2𝑡

104
σh = 52 mm
6.7 Longitudinal Stress:
σL =
𝑃𝑖 𝐷𝑖
4𝑡
σL = 26 mm
6.8 Weight Load:
𝐶𝑣 = 1.08
𝑊𝑣 = 240𝐶𝑣 𝐷(𝐻 + 0.8𝐷)𝑡
𝑊𝑣 = 15.14 𝑘𝑁
Weight of Catalyst = 724.55kN
Total Weight = 15.14+ 724.55
= 739.69 kN
6.9 Wind Load:
Wind Pressure = 1030 N/m2
Total Diameter = D + 2t
= 1.92 + 2*0.00412
= 1.93 m
F = PD
F = 1030 * 1.93
F = 1.996 N/m
6.10 Radial Stress:
𝜎𝑟 =
𝑃𝑖
2

105
𝜎𝑟 = 0.101 𝑁/𝑚𝑚2
6.11 Bending Moment:
𝑀𝑥 =
𝑊𝑋2
2
𝑀𝑥 = 33.457 𝑁𝑚𝑚
6.12 Dead Weight Stress:
𝜎 𝑤 =
𝑊𝑣
𝜋𝑡(𝐷𝑖 + 𝑡)
𝜎 𝑤 = 29.50 𝑁/𝑚𝑚2
6.13 Bending Stress:
𝐼𝑣 =
𝜋(𝐷𝑜
4
− 𝐷𝑖
4
)
64
𝐼𝑣 = 1.17 ∗ 1010
𝑚𝑚4
𝜎𝑏 =
𝑀𝑥
𝐼𝑣
(
𝐷𝑖
2
+ 𝑡)
𝜎𝑏 = 2.76
𝑁
𝑚𝑚2
6.14 Allowable Stress Intensity:
Circumferential Stress:
σ1 =
1
2
[σh + σ 𝑧 + √(σh − σ 𝑧)2 + 4𝑡2]
σ1 = 52 N/mm2
Longitudinal Stress:
σ2 =
1
2
[σh + σ 𝑧 − √(σh − σ 𝑧)2 + 4𝑡2]
σ2 = 32.27 N/mm2

106
Radial Stress:
σ3 = 0.5P
σ3 = 0.101 N/mm2
σ1 − σ2 = 19.73 N/mm2
σ1 − σ3 = 51.90 N/mm2
σ2 − σ3 = 32.17 N/mm2
σ1 − σ3 < 𝑓
The vessel wall thickness is sufficient to ensure the maximum stress intensity does not exceed the
design stress. [16] [17]

107
Specification Sheet
Identification
Item: Reactor R-100
Type : Packed Bed Catalytic Reactor
Function
To Produce Formaldehyde From Methanol Using Silver Catalyst
Operating Pressure 2 atm
Design Pressure 2.2 atm
Design Temperature 493 K
Wall Thickness 0.00412 m
Diameter Of Reactor (D) 1.929 m
Length Of Reactor (L) 5.789 m
Support Bracket
Pressure Drop 0.32 atm

Chapter No. 7 Pump Sizing
108
Chapter No.7
7 Pump Sizing

Chapter No.7 Pump Sizing
109
7.1 Pumps (P-100):
1. P1 and P2
P1 = 1.01 bar = 101325 Pa
P2 = 2.37 bar = 237100.5 Pa
2. Process Equipment
From Appendix E Figure E-1
The process equipment is Centrifugal Pump.
3. Z1 and Z2
From Appendix E Table E-1
Z1 = 0 m
Z2 = 0.61 m
ES and ED = 0.35 bar = 35000 Pa
4. Pump Work
Density of Process Fluid = ρ = 792 kg/m3
𝑊 =
𝑔
𝑔𝑐
(𝑍1 − 𝑍2) +
(𝑃1 − 𝑃2)
𝜌
− (𝐸𝑆 + 𝐸 𝐷)
𝑊 = 9.8 (0 − 0.61) +
(101325 − 237100.5)
792
−
35000
792
𝑊 = 221.6
𝐽
𝑘𝑔
5. Pump Shaft Power
Mass Flow rate = m = 2.68 kg/s
Efficiency =ηp= 45%

110
𝑃𝑝 =
𝑚𝑊
𝜂 𝑝
𝑃𝑝 =
2.68 ∗ 221.6
0.45
𝑃𝑝 = 1.32 𝑘𝑊 = 1.77 ℎ𝑝
Electric Motor Power
Efficiency = η = 86%
𝑃𝐸 =
𝑃𝑝
𝜂
𝑃𝐸 = 2.06 ℎ𝑝
6. Standard Electric Motor Power
Safety Factor = 10%
𝑃𝑝 = 2.06 ∗ 1.1
From Appendix E Figure E-5
𝑃𝑝 = 3 ℎ𝑝
Standard Electric Motor Power = 3 hp
NPSH:
NPSH =
1
g
(
Pa − Pv
ρ
− hfs) − Za
NPSH =
1
9.8
(
101325 − 40500
792
− 0) − 0
NPSH = 6.67 m

111
Specification Sheet
Identification:
Item: Pump (P-100)
Type: Centrifugal Pump
No. of Required: 1
Function
To increase the pressure from 1 atm to 2.4 atm
Inlet Flow rate 9661 kg/hr
Inlet Pressure 1 atm
Outlet Pressure 2 atm
Pump Work 221.6 J/kg
Shaft Power 1.77 hp
Motor Power 3 hp
Motor Type Squirrel Cage Induction Motor
NPSH 6.67 m
Pump (101):
Specification Sheet
Identification
Item: Pump (P-101)
Type: Centrifugal Pump
No. of Required: 1
Function
To increase the pressure from 1.5 atm to 1.8 atm
Inlet Flow rate 31942 kg/hr
Inlet Pressure 1.5 atm
Outlet Pressure 1.8 atm
Pump Work 107.90 J/kg
Shaft Power 2.06 hp
Motor Power 3 hp
Motor Type Squirrel Cage Induction Motor
NPSH 2 m

Chapter No. 8 Cost Estimation
112
Chapter No. 8
8 Cost Estimation

Chapter No.8 Cost Estimation
113
8.1 Equipment’s Cost:
Vaporizer (V-100):
Shell and Tube Heat Exchanger
Area = 66.08 m2
From Appendix F Figure F-1
Exchanger Cost in 2004 = 29000 $
Pressure Factor 1-10 = 1
Type Factor U-tube = 0.85
Equipment Cost in 2004 = 29000 $ * Pressure Factor * Type Factor
Equipment Cost in 2004 = 24650 $
2004 Cost Index = 509.2
2017 Cost Index = 591
Equipment Cost in 2017 = Ce
2017 Cost Index
2004 Cost Index
Reactor (R-100):
Material of Construction = Carbon Steel
Height of Reactor = 5.78 m
Dia = 1.92 m
Form Appendix F Figure F-2
Reactor Cost in 2004 = 20000 $
Pressure Factor 1-5 bar= 1
Material Factor CS = 1

114
2004 Cost Index = 541.20
2017 Cost Index = 676.60
2017 Cost Index
2004 Cost Index
Equipment Cost in 2017 = 25003.69 $
Absorber (A-100):
Column Height = 27 m
Column Dia = 1.64 m
Absorber Cost in 2004 = 100000 $
Pressure Factor 1-5 bar = 1
Material Factor CS = 1
Packing Height = 25 m
Packing Material = Pall Rings
From Appendix F Table F-1
Cost Of Packing Material = 1360 $/m3
Volume Of Packing =
𝜋𝐷2
4
∗ 𝑃𝑎𝑐𝑘𝑖𝑛𝑔 𝐻𝑒𝑖𝑔ℎ𝑡
= (3.14*1.642
/4)*25

115
= 52.78 m3
Total Cost of Packing = Packing Height * 1360 $/m3
=71785.424 $
Total Cost in 2004 = Cost Of Vessel + Cost of Packing
= 100000 $ + 71785.424 $
= 171785.42 $
Total Present Cost in 2017
2004 Cost Index = 541.20
2017 Cost Index = 676.60
2017 Cost Index
2004 Cost Index
Distillation Column (D-100):
Height of Column = 7.64 m
Diameter of column = 0.8 m
Form Appendix F Figure F-4
Bare cost= 18*1000 =18,000 $
Purchased cost= Bare cost from fig * Material factor * Pressure factor
Material factor = C.S = 1.0
Pressure factor = 1-5 bar = 1.0
Cost of vessel = 18,000 * 1.0 * 1.0
Cost of vessel in 2004= Ce = 18,000 $

116
Plate diameter = 0.8 m
Plate material = C.S
Plate type = Sieve plate
Installed Cost = Cost form fig * Material factor
Cost per plate = 290* 1.0
Cost per plate = 290 $
No of plates = 16
Cost of plates in 2004 = 16* 290 = 4640 $
Total Cost of equipment in 2004= Ce = Cost of Column + Cost of plates
Total Cost = Ce = 18000 + 4640 = 22640 $
2004 Cost Index = 541.2
2017 Cost Index = 676.6
Equipment Cost in 2017 = Ce ×
2017 Cost Index
2004 Cost Index
Cooler (E-100):
Shell and Tube Heat Exchanger
Area = 36.15 m2
Exchanger Cost in 2004 = 19000 $
Pressure Factor 1-10 = 1

117
Type Factor U-tube = 0.85
2004 Cost Index = 509.2
2017 Cost Index = 591
2017 Cost Index
2004 Cost Index
Pump (P-100):
Centrifugal Pump
Capacity = S = 3.38 L/s
a = 6900
b = 206
n = 0.9
Ce = a +bSn
Equipment Cost in 2007 = Ce = 7516.44 $
2007 Cost Index = 830.9
2017 Cost Index = 982.3
Equipment Cost in 2017 = Ce×
2017 Cost Index
2007 Cost Index
Pump (P-101)
Centrifugal Pump

118
Capacity = S = 6.9L/s
a = 6900
b = 206
n = 0.9
Ce = a +bSn
Equipment Cost in 2007 = Ce = 8071.74$
2007 Cost Index = 830.9
2017 Cost Index = 982.3
Equipment Cost in 2017 = Ce×
2017 Cost Index
2007 Cost Index
Equipment Cost in 2017 = 9542.50$
Blower:
Capacity = S = 182 kw
Ce = CSn
C= cost Constant = 1920 $
n = 0.8
Ce = 1920 * 182 0.8
Ce in 2007 = 123412.26$
2007 Cost Index = 830.9
2017 Cost Index = 982.3
Equipment Cost in 2017 = Ce ×
2017 Cost Index
2007 Cost Index

119
Table 8.1: Total Equipment Cost ($)
Equipments Cost($)
Vaporizer (V-100) 28609.88
Reactor (R-100) 25003.70
Absorber (A-100) 214763.52
Distillation (D-100) 28304.18
Cooler (C-001) 18744.40
Pump (P-100) 8886.03
Pump (P-101) 9542.51
Blower (B-100) 145899.47
Total 479753.69
8.2 Direct Cost
From appendix F Table F-4
Direct Cost = 3.6 * Equipment’s Cost
= 3.6 * 479753.69
=1727113.29
= $ 1.73 million
8.3 Indirect Cost:
Indirect Cost = 1.44 * Equipment’s Cost
Indirect Cost = 1.44 * 479753.69
= 690845.32
= $ 0.69 million
8.4 Fixed Capital Investment (FCI):
FCI = Direct Cost + Indirect Cost
FCI = 1727113.29 + 690845.32

120
= 2417958.61 $
= $ 2.42 million
8.5 Working Capital Investment (WCI):
WCI = 15% FCI
= 0.15*2417958.61
= 362693.79 $
WCI = $ 0.36 million
8.6 Total Capital Investment:
Total Capital Investment = WCI + FCI
= 362693.79+ 2417958.61
= 2780652.40 $
Total Capital Investment = $ 2.78 million
8.7 Raw Materials:
Methanol:
Flow rate = 9.66 ton/h
Cost = 500 $/ton
Total Cost = 1.59 million $/yr
Air:
Flow rate = 19.07 ton/h
Cost = 0.005 $/ton
Total Cost = 944.31 $/yr

121
Utilities:
Water:
Flow rate = 54.78 ton/hr
Cost = 0.01 $/ton
Total Cost = 5490.15 $/yr
Steam:
Flow rate = 18.23 ton/hr
Cost = 15 $/ton
Total Cost = 2.19 million $/yr
Catalyst:
Weight of Catalyst = 72.45 ton
Cost per ton = 100000 $/ton
Total Cost = 7.225 million $/year
8.8 Operating Labor:
Minimum Wage = 0.21 $/h
Capacity = 200 ton/day
=200,000 kg/day
Operating Labour = 40 h/day
Processing Step = 7
Operating Labour = 40 * 7= 280 h/day
Operating Cost of Labour = 280*330*0.21 = $ 19404

122
8.9 Total Production Cost:
Variable Cost:
Variable Cost = Raw Materials + Utilities + Miscellaneous Materials
Variable Cost = 11.05 million $/yr
Fixed Cost:
Table 8.2: Fixed Cost
Function Cost ($)
Maintenance 120897.93
Operating Labor 19404.00
Laboratory Cost 3880.80
Supervision 3880.80
Plant Overheads 9702.00
Capital Charges 241795.86
Insurance 24179.59
Local Taxes 48359.17
Royalties 24179.59
Total 496279.74
Fixed Cost = $ 0.50 million
Direct Production Cost = Variable Cost + Fixed Cost
= 11.55 million $/yr
Overhead Cost:
Overhead Cost = 30% (Direct Production Cost)
= 3.46 million $/yr
Manufacturing Cost = Overhead Cost + Direct Production Cost

123
8.10 General Expenses:
Table 8.3: General Expenses
Function
Percentage of Total
Production Cost
Cost ($)
Administration 2% 300201.08
Distribution and Marketing 2% 300201.08
Research and Development 5% 750502.70
Total 1350904.87
General Expenses = 1.35 million $/yr
Total Production Cost = Manufacturing Cost + General Expenses
Total Production Cost/Capacity (ton/year) = 16360958.96 /66000
= 247.89 $/ton
8.11 Depreciation:
Depreciation = D =
V− Vs
N
FCI = V = $ 2.42 million
Salvage Value = s = 5%
Number of Years = N = 20 yr
D = $ 0.11 million
8.12 Gross Earning:
Capacity = 66000 ton /yr
Selling Price = 300 $/ton [12]
Total Income = 19.80 million $/yr

124
Gross Income = Total Income – Total Production Cost – Depreciation
= 3.32 million $/yr
Taxes = 40% Gross Income
Taxes = 1.33 million $/yr
Net Income = Gross Income – Taxes
= 1.99 million $/yr
8.13 Rate of Return (ROR):
ROR =
Net Income
Total Capital Investment
∗ 100
= 71.73%
8.14 Payback Period:
Payback Period =
1
ROR
∗ 100
= 1.39years [19]

Chapter No.9 Instrumentation and Control
125
Chapter No. 9
9 Instrumentation and Control

126
9.1 Introduction
Measurement is a fundamental necessary to process control whether that control is affected
automatically, semi automatically, or manually. The quality of control obtainable also bears a
relationship to the precision, reproducibility and dependability of the measurement method which
are employed. So, selection of the most effective means for measurement is an important first
step in the design and formulation of any process control system.
In manual control an operator may periodically read the process variable and adjust the input up
or down in such a direction as to derive the temperature to its desired value. Manual control is
used in non- critical application, where any process condition occurs slowly and in small
increments and where a minimum of operator attention is required. While in programmed control,
measurement and adjustments are made automatically on a continuous basis. Today automatic
control is used in industry due to following benefits.
 Improvement in product quality
 Increase in process yield of production rate
 Rise safety for personnel and equipment
 Economics saving in materials, energy of time
 Improvement of working conditions
 Success of operation not possible by manual control
9.2 Control Mechanism
The Controllers reorganizes the offer signal and produces an output signal relative to some
function of the error. The output signal of the controller is the initiating force positioning of the
final control element.
9.3 Process Control
Control in one form or in another is an important part of any chemical engineering operation. In
all practices, there rises the necessity of keeping flows, pressures, temperatures, compositions,
etc. Within certain limits for reasons of safety or conditions. It is self-evident that automatic
control is highly desirable, as manual operation would necessitate continuous monitoring of the
controlled variable by a human operator and the efficiency of observation of the operator would
unavoidable fall off with time. Moreover, variabilities in the controlled variable may be too quick
and frequent.
9.4 Objectives of Instrumentation and Control System
 Suppressing and killing the external disturbances
 Operate the process in a stable manner

127
 Optimize the process operation
9.5 Components of the Control System
Following are the main components of a control system:
Process:
Any operation or series of operations that produce a desired final result in a process.
Measuring Element:
As all parts of control system, determining element is perhaps the most important. If
measurements are not made properly the Remaining of the system cannot operate suitably, also
the measured variable is chosen to symbolize the desired conditions in the process.
Controller:
The controller is the device that replies to any error detecting mechanism. The output of the
controller is determined function of the error. Final Control Element: The final control element
receives the signal from the controller and by some prearranged relationship change energy input
to the process.
9.6 Types of Control
Many different types of controls are used in industry dependent upon requirements and particular
needs. They range from very simple control to very complex system, in general they may be
divided into two major classes as follows:
 Feedback control.
 Feed forward control
9.7 Feedback Control
It is our general behavior that we leant from practice. A feedback control, as the name suggest, is
also founded on same principal. If any input to a system is changed it will change in the system
called as “disturbances”. These disturbances are noted down and modified action is taken on the
input to unwrap the effect that change.
Advantages
 It does not require the ID and measurement of disturbance.
 Effective for all disorders.
 Insensitive to modeling errors

128
 It can deliver zero steady state offset.
Disadvantages
 It waits until the effect of disturbance has been felt by the system.
 Poor response for slow processes or with significant dead time.
 It may create uncertainty in the closed loop response.
9.7 Feed Forward Control
In daily life experience we pride on being able to plan forward. No deriver of automobile waits
for his vehicle to leave the road before operating the steering wheel.
Relatively, he participate the effect of curbed road by introducing the corrective action before
controlled variable is affected. When this idea is properly applied to control system the loop that
is formed is called feed forward in appreciation of the fact that the manipulating variable is open
to a disturbance rather than to controlled variable.
Advantages
 It acts before the effect of disturbance has been handled by system.
 It is good for slow systems or systems with significant dead time.
 It does not introduce the uncertainty in control system.
Disadvantages
 It requires the ID of all possible disturbances and their direct measurement.
 Cannot handle with unmeasured disturbances.
 Complex to process parameter deviation.
 It cannot removed steady state offset.
 It needs good knowledge of process model.
In order to design a control system to work not only automatically but resourcefully, it is
frequently essential to obtain both steady state and dynamic behavior in which this knowledge is
gained is dependent essentially upon the process being controlled and control element to be
applied.
9.8 Process Variable
The operation of a process is rely upon the control of the process variables. These are defined as
situation in process materials or machine, which are subjected to alter the temperature, pressure,
flow and liquid level are the main variable, and trailed by perhaps a dozen less often encountered
variables such as chemical composition, viscosity, density, humidity, moisture content and so
forth. Measurement is a important requisite to process control either the control can be achieve
automatically, semi automatically or manual. The quality of control attainable also bears a

129
relationship to precision, reproducibility and reliability of the measurement technique, which are
selected.
So, selection of the most effective means of measurements is an significant first step in the design
and modeling of any process control system. An automatic control is used to measure, accurate
and modifies changes of the four principle types of process variations.
 Temperature measurements
 Pressure measurements
 Flow rate measurements
9.9 Temperature Measurement and Control
The temperature measurement is used to control the temperature of outlet and inlet Streams in
heat exchangers, reactors etc most temp measurement in the industry are made by means of
thermocouples to assist the bringing measurement to integrated location for local measurements
at the apparatus bi –metallic or filled system thermometers are used to a minor extent usually,
high measurements accuracy resistance thermometer are used .all these meters are installed with
thermo-walls when used locally .This delivers against atmosphere and other physical elements.
9.10 Pressure Measurement and Control
Like temperature, pressure is a variable indicating material state and composition. In fact, these
two measurements considered together are the primary calculating devices of industrial materials.
In the reactor, pressure measurements are of main importance. Pumps, compressors and other
process equipment related with pressure changes in the process material are done with pressure
measuring devices. Thus pressure measurements become a signal of energy increase or decrease.
Most pressure measurements in industry are elastic elements devices, either directly connected
for local use at show type to centralized location. Most widely used industrial pressure element is
bourdon tube or a diaphragm bellows.
9.11 Flow Measurement and Control
The measurement of flow is an important part of almost every industrial process, and many
procedures have been discovered for it. Measurement of flow usually occupy the same principle
as the measurement of pressure i.e., sensing device coupled with a DP cell.
For superior applications other flow meters may be applied e.g. for process no external
disturbance in the fluid stream is needed for magnetic flow meters. Flow indicator –controllers
are used to control the amount of liquid, also all manually set streams need some flow indication
or some easy means for occasional sample. Most flow measurements in industry are variable

130
head devices. To minor extent variables is used, as are the many available types as special
measuring situations arise.
Table 9.1: Various types of measuring instruments for Temperature, Pressure
Measured process variables Measuring devices Comments
Temperature
Thermocouples, resistance
Thermometer, thermistors
Thermometer bimetallic
Thermometers
Radiation
Pyrometers
Generally for relatively low
temperature.
Radiation pyrometers used
for high temperature
Pressure
Manometers
Bourdon tube elements
Bellow elements
Strain gauges
Capsule gauges
Thermal conductivity gauge
McLeod gauge
With float or displacers based
on the elastics distortion of
materials.
Used to convert pressure to
electric signals.
For measurement of
Vacuum
Table 9.2: Various types of measuring instruments flow Rate and level
Measured process variables Measuring devices Comments
Flow Rate
Orifice plate
Venture flow nozzle
Dell flow tube
Pitot tube
Dennison flow nozzle
Turbine flow meter
Hot wire anemometer
Positive displacement and
Mass flow meter
Measuring pressure drop
across a flow constriction.
Positive displacement and
Mass flow meter for high
accuracy. Quantity
Flow meter
Liquid Level
Float actuated devices
Displacer devices
Liquid head pressure
devices Dielectric
measurement
Coupled with Various
Types of indicators and signal
Converters good for system
with two phases.
Secondary method of
hydrostatic pressure.
9.12 Process Control System Hardware
According to Stephanopoulos (1984), the hardware elements that can be established in control
configuration include:

131
i. Chemical Process:
It indicates the material equipment together with the physical or chemical operations that occur
there.
ii. Sensor:
These type of measuring instruments are usually used for the measurement of the disturbances,
the controlled output variables, or secondary output variables. It represents the behavior of the
process. For instance, thermocouple, venture meter and gas chromatographs.
iii. Transducer:
It used to convert measurement to physical quantities (such as electrical voltage or pneumatic
signal) which can be transmitted easily
iv. Transmission line:
The line is used to carry the measurement signal from the measuring device to the controller.
Sometimes it is equipped with amplifier due to weak signal coming from a far measuring device.
v. Controller:
It is usually a hardware element of an instrument which has “intelligence” features. It accepts the
facts and decides what action should be taken.
vi. Final Control Element:
It implements in real life the decision taken by the controller. For example control valve.
vii. Recording Elements:
They are used to provide a visual demonstration of how a chemical process behaves.
9.13 Valve Selection
Valves used in chemical plants can be divided into two categories depending on their function:
1. Shut off valves – The main purpose of shut off valves is to close off the flow.
2. Control valves – They can be either automatic or manual and their objective is used to
regulate the flow.
Control Valves:
Selection of control valves is an important factor. It is important that good flow control is
achieved

132
Whilst the pressure drop is kept low as possible. Control valves may fail to open, this is occurs
when power supply failure happens. Diaphragm valves are commonly used in this case. This type
of valve can be seen in the figure below:
Figure 9.1: Diaphragm valve
Flanged Valves:
Flanged valves can be used for drainage. An example of the type of flanged valve used in this
case is shown in figure below. These are generally closed and are in operation usually during site
or unit maintenance.
Figure 9.2: Flanged Valve
Non- Return Valves:
This type of valve is used to prevent the back-flow of the fluid in the process. It is important that
non-return valves have been correctly installed to ensure they are working adequately, i.e. they
should be fitted in the correct orientation. An example of this type of valve is shown in figure
below:
Figure 9.3: Non-return valve
Gate Valves:
Gate valves are frequently used for shut –off purposes. It is important that a valve selected for
this purpose gives a positive seal in the closed position and minimum resistance to the flow when
the valves are open. Gate valves exist in a wide range of sizes and it is possible to operate them
manually or automatically by the use of a motor. When gate valves are fully open they have a low
pressure drop. When operating gate valves attention must be paid to ensure they are not operated
partially open. This is because the valve seal can become deformed, so as a result the valve will
not seal properly. Below figure shows a diagram of a gate valve which has been frequently used
in the piping and instrumentation diagram.

133
Figure 9.4: Gate valve
Instrumentation and Control on Distillation Column:
DT-100
FT-1
FIC
100
TIC
100
TT-1
Set Point
Reboiler Bottom Product
Feed
TIC
101
FIC
101
FT-2
TT-2
Set Point Reflux Drum
Condensor
Top Product
V-1
V-2
V-3 V-1
Figure 9.5: Instrumentation and Control on Distillation Column

Chapter No.10 Hazop Study
134
Chapter No.10
10 Hazop Study

135
10.1 Background:
A HAZOP study identifies hazards and operability problems. The concept involves investigating
how the plant might deviate from the design intent. If, in the process of identifying problems
during a HAZOP study, a solution becomes apparent, it is recorded as part of the HAZOP result;
however, care must be taken to avoid trying to find solutions which are not so apparent, because
the prime objective for the HAZOP is problem identification. Although the HAZOP study was
developed to supplement experience based practices when a new design or technology is
involved, its use has expanded to almost all phases of a plant's life. HAZOP is based on the
principle that several experts with different backgrounds can interact and identify more problems
when working together than when working separately and combining their results. The "Guide-
Word" HAZOP is the most well-known of the HAZOPs; however, several specializations of this
basic method have been developed.
10.2 Introduction:
The HAZOP study is a formal procedure to identify hazards in a chemical process facility. The
procedure is effective in identifying hazards and is well accepted by the chemical industry. The
basic idea is to let the mind go free in a controlled fashion in order to consider all the possible
ways that process and operational failures can occur. Before the HAZOP study is started, detailed
information on the process must be available. This includes up-to-date process flow diagrams
(PFDs), process and instrumentation diagrams (P&IDs), detailed equipment specifications,
materials of construction, and mass and energy balances.
The full HAZOP study requires a committee composed of a cross-section of experienced ' plant,
laboratory, technical, and safety professionals. One individual must be a trained HAZOP leader
and serves as the committee chair. This person leads the discussion and must be experienced with
the HAZOP procedure and the chemical process under review. One individual must also be
assigned the task of recording the results, although a number of vendors provide software to
perform this function on a personal computer. The committee meets on a regular basis for a few
hours each time. The meeting duration must be short enough to ensure continuing interest and
input from all committee members. A large process might take several months of biweekly
meetings to complete the HAZOP study. Obviously, a complete HAZOP study requires a large
investment in time and effort, but the value of the result is well worth the effort.
10.3 Success or Failure:
The success or failure of the HAZOP depends on several factors.
 The completeness and accuracy of drawings and other data used as a basis for the study.
 The technical skills and insights of the team.

136
 The ability of the team to use the approach as an aid to their imagination in visualizing
deviations, causes, and consequences.
10.4 Hazop Characteristics:
HAZOP is best suited for assessing hazards in facilities, equipment, and processes and is capable
of assessing systems from multiple perspectives:
Design:
Assessing system design capability to meet user specifications and safety standards. Identifying
weaknesses in systems
Physical and operational environments:
Assessing environment to ensure system is appropriately situated, supported, serviced, contained,
etc.
Operational and procedural controls:
Assessing engineered controls (ex: automation), sequences of operations, procedural controls etc.
Assessing different operational modes start-up, standby, normal operation, steady & unsteady
states, normal shutdown, emergency shutdown, etc.
10.5 Advantages:
1. Helpful when confronting hazards that are difficult to quantify that is,
 Hazards rooted in human performance and behaviors
 Hazards that are difficult to detect, analyze, isolate, count, predict, etc.
 Methodology doesn’t force you to explicitly rate or measure deviation probability of
occurrence, severity of impact, or ability to detect
2. Built-in brainstorming methodology.
3. Systematic & comprehensive methodology.
4. More simple and intuitive than other commonly used risk management tools.
10.6 Disadvantages:
1. No means to assess hazards involving interactions between different parts of a system or
process.
2. No risk ranking or prioritization capability. Teams may optionally build-in such capability as
required.
3. No means to assess effectiveness of existing or proposed controls (safeguards). May need to
interface HAZOP with other risk management tools.

137
10.7 Effectiveness:
The effectiveness of a HAZOP will depend on:
 The accuracy of information (including P&IDs) available to the team information
 Should be complete and up-to-date
 The skills and insights of the team members
 How well the team is able to use the systematic method as an aid to identifying
 Deviations
 The maintaining of a sense of proportion in assessing the seriousness of a hazard
 The expenditure of resources in reducing its likelihood
 The competence of the chairperson in ensuring the study team rigorously follows
 Sound procedures.
10.8 Key Elements:
Key elements of a HAZOP are:
 HAZOP team.
 Full description of process.
 Relevant guide words.
 Conditions conducive to brainstorming.
 Recording of meeting.
 Follow up plan.
Table 10.1: Guide Words
Guide Words Meaning
No
Less
More
Part of
As well as
Reverse
Other than
Negation of design intent
Quantitative decrease
Quantitative increase
Qualitative decrease
Qualitative Increase
Logical opposite of the intent
Complete substitution

138
10.9 Hazop Study on Reactor R-100:
Table 10.2: Hazop Study on Reactor (R-100)
Guide Deviation Cause Consequences Action
No
Flowrate
 No Feed in storage
tank
 Feed pump rupture
 Supply pipe
rupture
 Valve is closed
 Pump is off
 Decrease in
production
or no
production
 Cleaning of
line
 Level control
system
 Maintenance
of pipes
 Automatic
valve
 Automatic
pump
Level  Blockage in line
 Valve is closed
 Decrease in
production
or no
production
 Maintenance
of pipes
 Automatic
valve
Temperature  Fault in Preheater
 Steam pipe rupture
 Decrease in
production
or no
production
 Maintenance
of pipes
Pressure  Fault in Preheater
 Decrease in
production
or no
production
 Maintenance
of Preheater
More
Flowrate
 More valve
opening
 Explosion
 Less
conversion
 Automatic
valve
 Check reactor
conditions
Level  More valve
opening
 Overflow  Check Valve
Temperature  Fault in Preheater  Explosion  Maintenance
Pressure
 Fault in Preheater
 Less
production
 Check valve.

139
Less
Flowrate
 Less of opening of
valves
 Less
production
 Automatic
valve
 Temperature
control at
reactor feed
preparation
Level  Less of opening of
valves
 Less
Production
 Check Valve
Temperature  Fault in Preheater
 Low
Conversion
 Temperature
Control
Pressure
 Fault in Preheater
 Less
Production
 Maintenance
As well as
Impurities in
feed stream
 Problem in raw
material
 Fouling in pipes
 Low
conversion
rate
 Decrease in
product
quality
 Quality control
of raw
material and
product
 Maintenance
Part of
Higher or
Lower
percentage of
Feed
 High quality of
feed
 Less quality of
feed
 More or less
pure
production
than
intended
 Quality control
of raw
material and
product
Other than
Replacement
of Raw
Material
 Wrong connection
during plant
modification
 Explosion
 Better
management
of changing
procedure

Chapter No. 11 Environmental Impact Assessment
140
Chapter No. 11
11 Environmental Impact Assessment

141
11.1 Environmental Impact Assessment:
Environmental Impact Assessment (EIA) is the process of assessing the likely environmental
impacts of a proposal and identifying options to minimize environmental damage. The main
purpose of EIA is to inform decision makers of the likely impacts of a proposal before a decision
is made. EIA provides an opportunity to identify key issues and stakeholders early in the life of a
proposal so that potentially adverse impacts can be addressed before final approval decisions are
made. The EIA also includes a description of the measures taken to avoid, reduce or remedy
these effects.
11.1.1 Overview:
The US Environmental Protection Agency Pioneered the use of pathway analysis to determine
the likely human health impact of environmental factors. The technology for performing such
analysis is properly called as environmental science. The principal phenomenon or pathways of
impact are:
Noise and health effects
Water pollution impacts
Ecology impacts including endangered species assessment
Air pollution impacts
Soil contamination impacts
Geological hazards assessment
11.1.2 Objectives:
 Ensuring environmental factors are considered in the decision-making process.
 Ensuring that possible adverse environmental impacts are identified and avoided or
minimized.
 Informing the public about the proposal.
11.1.3 Advantages:
 Allows people to examine the underlying need for a project.
 Gives people the opportunity to identify problems.
 Helps a developer to design a more publicly acceptable project.
11.2 Methanol:
Methanol, also known as methyl alcohol among others, is a chemical with the formula CH3OH..
Methanol acquired the name wood alcohol because it was once produced chiefly as a byproduct
of the destructive distillation of wood. Today, industrial methanol is produced in a catalytic
process directly from carbon monoxide, carbon dioxide, and hydrogen. Methanol is a colorless
liquid that boils at 64.96 °C (148.93 °F) and solidifies at −93.9 °C (−137 °F). It forms explosive
mixtures with air and burns with a no luminous flame. It is completely miscible in water.

142
Methanol has an odor that is similar to ethyl alcohol, the intoxicant of alcoholic beverages, but is
a dangerous poison; many cases of blindness or death have been caused by drinking mixtures
containing it.
11.2.1 Hazard:
11.2.1.1 Fire Hazards:
Highly flammable in presence of open flames and sparks, of heat. Non-flammable in presence of
shocks. Risks of explosion of the product in presence of mechanical impact: Not available.
Explosive in presence of open flames and sparks, of heat. Flammable liquid, soluble or dispersed
in water. Small Fire Use Dry chemical powder. Large Fire: Use alcohol foam, water spray or fog.
Explosive in the form of vapor when exposed to heat or flame. Forms an explosive mixture with
air due to its low flash point. Explosive when mixed with Chloroform, sodium methoxide and
diethyl zinc. It boils violently and explodes.
11.2.1.2 Health Hazard:
Hazardous in case of skin contact, of eye contact (irritant), of ingestion, of inhalation. Slightly
hazardous in case of skin contact (permeator). Severe over-exposure can result in death. The
substance is toxic to eyes. The substance may be toxic to blood, kidneys, liver, brain, peripheral
nervous system, upper respiratory tract, skin, central nervous system (CNS), optic nerve.
Repeated or prolonged exposure to the substance can produce target organs damage.
11.2.2 Protective measures
Eye Protection:
Check for and remove any contact lenses. Immediately flush eyes with running water for at least
15 minutes, keeping eyelids open. Cold water may be used. Get medical attention.
Skin Contact:
Wear chemical protective clothing e.g. gloves, aprons, boots. In some operations wear a chemical
protective, full-body encapsulating suit and self-contained breathing apparatus (SCBA).In case of
contact, immediately flush skin with plenty of water for at least 15 minutes while removing
contaminated clothing and shoes. Cover the irritated skin with an emollient.
Inhalation Protection:
If inhaled, remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult,
give oxygen. Get medical attention immediately.

143
11.2.3 Spills and emergencies
Dilute with water and mop up, or absorb with an inert dry material and place in an appropriate
waste disposal container. Flammable liquid. Poisonous liquid. Keep away from heat. Keep away
from sources of ignition. Stop leak if without risk. Absorb with Dry earth, sand or other non-
combustible material. Do not get water inside container. Do not touch spilled material [13]
.
11.3 Formaldehyde:
Formaldehyde (systematic name methanal), is a naturally occurring organic compound with the
formula CH2O (H-CHO). It is the simplest of the aldehydes. Formaldehyde is a colorless
poisonous gas synthesized by the oxidation of methanol and used as an antiseptic, disinfectant,
histologic fixative, and general-purpose chemical reagent for laboratory applications.
Formaldehyde is readily soluble in water and is commonly distributed as a 37% solution in water;
formalin, a 10% solution of formaldehyde in water, is used as a disinfectant and to preserve
biological specimens. Environmentally, formaldehyde may be found in the atmosphere, smoke
from fires, automobile exhaust and cigarette smoke. Small amounts are produced during normal
metabolic processes in most organisms, including humans.
11.3.1 Hazards:
11.3.1.1 Fire Hazards:
Formaldehyde becomes a fire or explosion hazard in the presence of heat, flames or other sources
of ignition. Upon ignition, the chemical decomposes into carbon oxides (i.e. carbon monoxide,
carbon dioxide), which can be hazardous to humans. Use dry Chemical, CO2, water spray or
alcohol resistant foam as extinguisher agents. Use water spray to reduce the vapors.
11.3.1.2 Health Hazard:
Formaldehyde can be highly toxic if swallowed, inhaled or absorbed though skin. Ingestion of as
little as 30 mL of a solution containing 37% formaldehyde has been reported to cause death in
adults. Formaldehyde is classified as a suspected human carcinogen, based on evidence obtained
from human and/or animal studies. Exposure to formaldehyde can lead to allergic reactions in
certain individuals. Sensitization is an immune response. Formaldehyde can become irritating to
the eyes at low concentrations. Irreversible damage. At concentrations near 0.1 parts per million
(ppm), exposure to formaldehyde can be irritating to the skin, eyes and respiratory tract.
Symptoms of exposure include coughing, wheezing, dermatitis, headaches, watery eyes, nausea,
chest tightness and burning sensations in the eyes, nose and throat. Long-term exposure can result
in headaches, insomnia, depression, mood changes, attention deficit and impairment of dexterity,
memory and equilibrium.

144
11.3.2 Protective measures
11.3.2.1 Eye Protection:
Tight-fitting safety goggles or a full face shield (8-inch minimum) should be worn when handling
formaldehyde.
11.3.2.2 Foot Protection:
Closed-toed footwear is required in all laboratories with hazardous chemicals.
11.3.2.3 Hand Protection:
Concentrated formaldehyde solutions (i.e. 10% or greater) should be handled with medium or
heavyweight nitrile, neoprene, natural rubber or PVC gloves.
11.3.2.4 Skin and Body Protection:
In most laboratories, a lab coat or chemical-resistant apron should be worn when handling
formaldehyde. Further protection for the body may be necessary depending on the concentrations
of formaldehyde being used and operations being performed.
11.3.2.5 Respiratory Protection:
Researchers working in labs with formaldehyde that have exceeded the OSHA action level,
permissible exposure limit or short-term exposure limit may be required to wear respiratory
protection. All employees required to wear respirators in laboratories must have a medical
evaluation, training and a fit test prior to use.
11.3.3 Spills and emergencies:
Evacuate the personal and secure and control entrance to area. Eliminate all the ignition source.
Absorb liquids in vermiculite, dry sand, earth, or a similar material and place into sealed
container for disposal. Ventilate and wash area after clean-up is complete [1]
.

145
References:
[1]. Formaldehyde,” Wikipedia. Wikimedia Foundation, Web
Web < http://en.wikipedia.org/wiki/Formaldehyde>
[2]. "Formaldehyde Production from Methanol." McMaster University,
[3]. Couper, James R. Chemical Process Equipment: Selection and Design. Amsterdam: Elsevier,
2005. Print.
[4]. Felder, Richard M., and Ronald W. Rousseau. Elementary Principles of Chemical Processes.
New York: Wiley, 2005. Print.
[5]. Kirk, Raymond E., Donald F. Othmer, Jacqueline I. Kroschwitz, and Mary Howe-Grant.
Encyclopedia of Chemical Technology. New York: Wiley, 1991. Print.
[6]. Rosaler, Robert C. Standard Handbook of Plant Engineering. New York: McGraw-Hill,
1995. Print.
[7]. ScienceLab: Chemicals & Laboratory Equipment." ScienceLab: Chemicals & Laboratory
Equipment Web <http://www.sciencelab.com/>.
[8]. Smith, J. M., Hendrick C. Van. Ness, and Michael M. Abbott. Introduction to Chemical
Engineering Thermodynamics. New York [etc.: McGraw-Hill, 2001. Print.
[9]. Holman, J. P. Heat Transfer. New York: McGraw-Hill, 2010. Print.
[10]. Holland, Charles Donald. Fundamentals of Multicomponent Distillation. New York:
McGraw-Hill, 1981. Print.
[11]. Fair, James R. Advanced Process Engineering. New York, NY: American Institute of
Chemical Engineers, 1980. Print.
[12]. Alibaba Manufacturer Directory - Suppliers, Manufacturers, Exporters & Importers."
Alibaba. Web. <http://www.alibaba.com/>.
[13]. Methanol." Wikipedia. Wikimedia Foundation,. Web.
<http://en.wikipedia.org/wiki/Methanol>.
[14].https://www.academia.edu/6244446/iii_MANUFACTURE_OF_FORMALDEHYDE_FRO
M_METHANOL_A_PROJECT_REPORT
[15]. Perry, R.H., and D.W. GREEN, Perry’s chemical engineers’ Handbook, Seventh edition,
McGraw-Hill, 1997.

146
[16]. Coulson, J.M., J.F. Richardson, “Chemical Engineering” Volume 1 Sixth Edition
[17]. Coulson, J.M., J.F. Richardson, “Chemical Engineering” Volume 6 Sixth Edition
[18]. Kern, Donald Q. Kern “Process Heat Transfer”. First Edition.
[19]. Max S. Peter,Klaus D. Timmerhaus , Ronald E West “Plant Design and Economics of
Chemical Engineering” Fifth Edition.
[20]. Fogler Scott, “Element of Chemical Reaction Engineering” Fifth Edition
[21]. Ludwig, “Applied Process Design for Chemical Plants, Volume 2
[22]. Dyena Company of Formaldehyde, Web http://www.dynea.com/technology-sales/silver-
catalysed-formaldehyde-plant/operational-cost/
[23]. Wah Noble Company Web http://www.wah noble company.com.pk
[24]. ZRK Peshawar Web. http://www.ZRKpeshawar.com.pk
[25].http://www.referatele.com/referate/engleza/online2/FORMALDEHYDE---Physical-
Properties-Chemical-Structure-Preparation-Methods-Reactions-Usagem-Danger-Ma.php

148
Appendix A:
Figures:
Figure A-1: JH Factor
Figure A-3: Reynolds Number
Tables:
Table A-1: Design Coefficient
Table A-2: OD of Tubes in Triangular Pitch

149
Figures:

150
Figure A-3: Reynolds Number

151
Table:
Table A-1: Design Coefficient
Table A-2: OD of Tubes in Triangular Pitch

152
Appendix B:
Figures:
Figure B-1: Generalized Pressure Drop correlation
Figure B-2: Number of transfer units NOG as a function of Y1/Y2 with mGm/Lm as parameter
Figure B-3: Generalized correlation for pressure drop
Tables:
Table B-1: Design data for various packing’s

153
Figures:
Figure B-1: Generalized Pressure Drop correlation
Figure B-2: Number of transfer units NOG as a function of Y1/Y2 with mGm/Lm as parameter

154
Figure B-3: Generalized correlation for pressure drop

155
Tables:
Table B-1: Design data for various packing’s

156
Appendix C:
Figures:
Figure C-1: Flow Factor
Figure C-2: (Ad/Ac)*100 vs. lw / Dc
Figure C-3: K2
Figure C-4: Orifice Coefficient Co

157
Figures:
Figure C-2: (Ad/Ac)*100 vs. lw / Dc
Figure C-1: Flow Factor

158
Figure C-3: K2
Figure C-4: Orifice Coefficient Co

159
Appendix D:
Figures:
Figure D-1: Shell side heat-transfer Curve
Figure D-2 Tube Side heat-transfer Curve
Figure D-3 Friction Factor
Tables:
Table D-1: Design Coefficient
Table D-2: Tube-Sheet Layout Square Pitch
Table D-3: Heat Exchanger Tube Data

160
Figures:
Figure D-1: Shell side heat-transfer Curve
Figure D-2 Tube Side heat-transfer Curve

161

162
Tables:
Table D-1: Design Coefficient
Table D-2: Tube-Sheet Layout Square Pitch

163
Table D-3: Heat Exchanger Tube Data

164
Appendix E:
Figures:
Figure E-1: Pump Selection
Tables:
Table E-1: Process Equipment
Table E-2: Pressure Drop
Table E-3: Pump Type
Table E-4: Efficiency
Table E-5: Horsepower

165
Figures:
Figure E-1: Pump Selection

166
Tables:
Table E-1: Process Equipment
Table E-2: Pressure Drop

167
Table E-3: Pump Type
Table E-4: Efficiency

169
Appendix F:
Figures:
Figure F-1: Vaporizer Cost
Figure F-2: Reactor Cost
Figure F-3: Absorber Cost
Figure F-4: Distillation Cost
Figure F-5: Exchanger Cost
Figure F-5: Operating Labor (h/day)
Tables:
Table F-1: Absorber Packing Cost
Table F-2: Pump Cost
Table F-3: Blower Cost
Table F-4: Direct & Indirect Cost
Table F-5: Variable & Fixed Cost

170
Figures:
Figure F-1: Vaporizer Cost
Figure F-2: Reactor Cost

171
Figure F-3: Absorber Cost
Figure F-4: Distillation Cost

172
Figure F-4: Distillation Plate Cost
Figure F-5: Exchanger Cost

173
Figure F-5: Operating Labor (h/day)

174
Tables:
Table F-1: Absorber Packing Cost
Table F-2: Pump Cost

175
Table F-3: Blower Cost
Table F-4: Direct & Indirect Cost

176
Table F-5: Variable & Fixed Cost

Production of 66000 ton/year of Formaldehyde from Methanol using Silver catalyst. Final year project - BSC Chemical Engineering 2014-2018

More Related Content

What's hot (20)

Similar to Production of 66000 ton/year of Formaldehyde from Methanol using Silver catalyst. Final year project - BSC Chemical Engineering 2014-2018 (13)

Recently uploaded (20)

Production of 66000 ton/year of Formaldehyde from Methanol using Silver catalyst. Final year project - BSC Chemical Engineering 2014-2018