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
Passes = 1 Passes = 2
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 = 30735.90 kg/hr
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
ʃG = Density of Gas = 3.2 kg/m3
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 

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

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