This document provides a process description and material and energy balance for producing vinyl chloride monomer (VCM) from ethylene and chloride. The process involves three main sections: producing ethylene dichloride (EDC) through direct chlorination or oxychlorination, distilling the EDC, and cracking the EDC to produce VCM. Mass and energy balances were developed to size major equipment and estimate capital and operating costs. The overall annual operating cost to produce 150,000 lb/hr of VCM was estimated to be nearly $2 billion. Safety considerations are also discussed.
2. 2
Contents
I. Executive Summary…………………………………………………………………..3
II. Process Description…………………………………………………………………...3
III. Flowsheet……………………………………………………………………………...8
IV. Overall Balance…...…………………………………………………………………...8
V. Process Economics…………………………………………………………………...11
VI. Major Equipment Lists and Capital Cost Estimate…...……………………………...11
VII. ISBL Estimate………………………………………………………………………..13
VIII. Safety………………………………………………………………………………...13
3. 3
I. Executive Summary
Vinyl Chloride (VCM) is made from Ethylene (𝐶2 𝐻4) and Chloride(𝐶𝑙2). Vinyl Chloride is used
to produce standard plastic material Polyvinyl Chloride (PVC). In this case, the Process of
making VCM by two methods that are Direct Chlorination and OxyChlorination is introduced;
and based on it, with information that is also given in the article, and calculation of Material and
Energy Balance to Estimate the Capital and Operating Cost for this Process. Besides, the safety
rules are given in this case to ensure safe operation and ensure efficient operation.
II. Process Description
1. General Process Description
The process to produce Vinyl Chloride monomer (VCM) from ethylene and chloride has three
main process sections.
The first section is produced Ethylene Dichloride (EDC) by direct chlorination
The second section, EDC is produced by oxychlorination.
The last section is cracking section to produce Vinyl Chloride (VCM) from EDC.
Both reactions in first and second section are exothermal, and the last section is endothermal.
4. 4
2. Direct Chlorination
This process operates at boiling condition with temperature of 1200C.
A big portion of the heat of reaction removes by boiling of EDC can be recover by process like
heating of Distillation Column or Heating of Fluidised Bed PVC Dryer.
Reaction is carried out in the riser section of CNC Reactor where gaseous ethylene is first
completely Pre-dissolved in the lower part of it.
Gaseous Chlorine is added through an injector nozzle in the lower section of CNC Reactor where
it is cooled to allow the chorine for better pre-dissolved. This pre-dissolved Chlorine is mixed
with Ethylene solution to react to EDC in a fast liquid-phase reaction.
The EDC is started boiling due to reduce statics pressure head in upper part of riser from where
excess EDC and product EDC are recover.
Thus, the energy efficiency of a HTC and EDC purity of LTC is combined by the process of
Vinnolit Direct Chlorination.
3. Oxychlorination
5. 5
EDC formation takes place in a fluidsed-bed reactor in Oxychlorination Process. The reaction
heat is used for steam generation and reaction gaseous is supplied to Quench Column after
Catalyst Filtration from where water is removed by condensation.
The reaction gaseous coming out of Quench Column is farther cooled and is feed to EDC
Distillation Column.
Moreover, depending on customer requirement, the gaseous coming out of the Quench Column
is refrigerated for waste water treatment.
4. EDC Distillation
The raw EDC produce from Oxychlorination Unit is feed to Head Column for EDC Distillation.
From Head Column, the gaseous substance is cooled with cooling water and supplied to
incineration unit.
The Dry Bottom Product from Head Column and uncovered EDC are supplied to high boiling
column and vacuum column. From here, High Boiling Compound is separated from unconverted
EDC. The High Volume Compound coming out of Vacuum Column is sent to incineration unit
and product from this process is supplied to cracking EDC Process.
6. 6
5. EDC Cracking
The cracking of product supplied from EDC Distillation Column takes place in Cracking
Furnace. Few and Combustion air is supplied to the cracking furnace to carry out that Cracking.
VCM, HCl and by product of various chemical structures and coke are formed and supplied to
EDC Evaporator where the formation of coke is reduced. The product are thus supplied to
Quench Column from where the Cracking Product goes to VCM Distillation.
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6. VCM Distillation
The product from Cracking Quench and the Cracking Unit Product are supplied to HCl Column
from where HCl is recovered and fed to VCM Column. Vinyl Chloride is obtained on top of
VCM Column which is supplied to HCl Stripper to remove any traces of HCl. The head product
of HCl is stripper ise supplied to HCl Column. The bottom product is cooled to form VCM
Product.
The bottom product of VCM Column (un-converted EDC) undergo heat recovery to return to
EDC Distillation Process.
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III. Flow Sheet:
Flowsheet is shown in the following Excel File
An Minh Tran -
Cheg 407 - Case 1.xlsx
IV. Overall Balance
1. Material Balance
Following Table from the Article, to Produce 1000 kg VCM product:
Ethylene 459 kg
Chlorine 575 kg
Oxygen 139 kg
Steam 250 kg
Fuel Gas 2.7 GJ
9. 9
459 kg of Ethylene will produce 1025 kg of VCM in theorical. Percent Yield is:
1000 𝑘𝑔
1025 𝑘𝑔
× 100% = 98%
Reaction to produce VCM:
Direct Chlorination: 𝐶2 𝐻4 + 𝐶𝑙2 → 𝐶2 𝐻3 𝐶𝑙 + 𝐻𝐶𝑙
Oxychlorination: 2𝐶2 𝐻4 + 𝐶𝑙2 +
1
2
𝑂2 → 2𝐶2 𝐻3 𝐶𝑙 + 𝐻2 𝑂
To produce 150000 lb/h VCM with 98% Yield, the process need:
Ethylene 31229.81 kg/h
Chlorine 39122.31 kg/h
Oxygen 9457.390 kg/h
Steam 17009.70 kg/h
Fuel Gas 183.7048 GJ/h
Assume that 75% VCM will be produce from Direct Chlorination, and 25% VCM will be
produce from Oxychlorination:
Direct Chlorination Oxychlorination
Ethylene 23422.36 kg/h Ethylene 7807.45 kg/h
Chlorine 29341.73 kg/h Chlorine 9780.58 kg/h
Steam 12757.28 kg/h Steam 4252.43 kg/h
Fuel Gas 137.7786 GJ/h Fuel Gas 45.9262 GJ/h
Reaction to produce EDC:
𝐷𝑖𝑟𝑒𝑐𝑡 𝐶ℎ𝑙𝑜𝑟𝑖𝑛𝑎𝑡𝑖𝑜𝑛:2𝐶2 𝐻4 + 𝐶𝑙2 → 𝐶2 𝐻4 𝐶𝑙2 + 218
𝑘𝐽
𝑚𝑜𝑙𝑒
𝑂𝑥𝑦𝑐ℎ𝑙𝑜𝑟𝑖𝑛𝑎𝑡𝑖𝑜𝑛: 𝐶2 𝐻4 + 2𝐻𝐶𝑙 +
1
2
𝑂2 → 𝐶2 𝐻4 𝐶𝑙2 + 𝐻2 𝑂 + 238
𝑘𝐽
𝑚𝑜𝑙𝑒
Mass of EDC
From Direct Chlorination 40415.05 kg/h
From Oxychlorination 26943.36 kg/h
2. Energy Balance
10. 10
a) Heat Exchanger:
To calculate the Area of the Heat Exchangers that are used in this Process, the equation is used
for Energy Balance:
𝑄 = 𝑚 𝑐̇ 𝑐 𝑝𝑐(𝑇𝑐,𝑜𝑢𝑡 − 𝑇𝑐,𝑖𝑛 ) = 𝐶𝑐(𝑇𝑐,𝑜𝑢𝑡 − 𝑇𝑐,𝑖𝑛)
𝑄 = 𝑚ℎ̇ 𝑐 𝑝ℎ(𝑇ℎ,𝑜𝑢𝑡 − 𝑇ℎ,𝑖𝑛) = 𝐶ℎ(𝑇ℎ,𝑜𝑢𝑡 − 𝑇ℎ,𝑖𝑛 )
𝑄 = 𝑚ℎ̇ 𝑐 𝑝ℎ(𝑇ℎ,𝑜𝑢𝑡 − 𝑇ℎ,𝑖𝑛) = 𝑈𝐴 𝑆∆𝑇𝑙𝑚
𝑄: Rate of Heat Transfer (W)
𝑐 𝑝: Specific Heat at Constant Pressure (kJ/kg-C)
𝐶 = 𝑚̇ 𝑐 𝑝 (W/oC)
𝑈: Overall Heat-transfer Coefficient (W/m2oC)
𝐴 𝑠 : Surface Area (m2)
∆𝑇 𝑚: Log mean Temperature Difference (oC)
Mass Flowrate is calculated by Mass Balance, Temperature is gotten from article and Overall
Heat-Transfer Coefficients is assumed 600 W/m2-C (from Chemical Engineering Design Book).
The Area of each type of Heat Exchange is shown following this table:
Process Heat Exchanger Area (m2)
Direct Chlorination Heat Recovery 30.00091371
Cooling Water 24.79641599
Oxychlorination Cooling Water 23.87373533
EDC Cracking Cooling Water 37.65408623
EDC Distillation Steam Cond. 37.65408623
VCM Distillation Refrigerant (HCl Column) 37.65408623
Cooling Water (VCM Column) 30.65298463
b) Cracking Furnace:
To calculate the Duty of Cracking furnace that is shown in EDC Cracking Process, the following
equation is used:
𝑄 = 𝑚̇ ∆𝐻𝑟𝑥𝑛 + 𝑚̇ 𝐶𝑝∆𝑇
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Following the article, ΔHrxn = -71 kJ/mole, and based on number of EDC Mass Flowrate that is
calculate in Mass Balance, the Duty of Cracking Furnace is: 14.26 MW.
V. Process Economics
Assume the Cost of each Material is following this table:
Natural Gas $ 2.50 MMBTU $ 2.64 GJ
Steam $ 2.00 lb $ 4.41 kg
Ethylene $ 0.60 lb $ 1.32 kg
Chlorine $ 1.50 lb $ 3.31 kg
Capacity 150000 lb/h 68038.936 kg/h
Operating Year 8000 h/year
Based on Material Balance, total Cost to Produce 150000 lb/hr of VCM in a year:
Natural Gas $ 3,876,170.44
Steam $ 599,998,797.02
Ethylene $ 330,479,337.40
Chlorine $ 1,034,997,924.87
Total $ 1,969,352,229.73
VI. Major Equipment Lists and Capital Cost Estimate
Process Equipment Unit for Size Number # of Equip. Total Cost ($)
Direct CNCReactor Volume (m3) 8.060762891 1 $ 216,044.61
Chlorination Condenser Area (m2) 30.00091371 2 $ 62,397.13
Heat Exchanger Area (m2) 24.79641599 2 $ 61,089.68
Vessel Strippingcolumn Mass (kg) 11731.14699 1 $ 169,597.74
Tray of StrippingColumn Diameter (m) 1.5 50 $ 80,823.73
ProductVessel Mass (kg) 11731.14699 1 $ 109,417.90
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Oxychlorination HydrogenationReactor Volume (m3) 0.851282985 1 $ 90,072.12
OxychlorinationReactor Volume (m3) 3.678173287 1 $ 153,627.46
BoilerFeedWater Mass Flowrate (kg/h) 4252.425 1 $ 166,524.25
Vessel QuenchColumn Mass (kg) 14070.59392 1 $ 213,805.64
Tray of QuenchColumn Diameter (m) 2.7 39 $ 188,974.03
CatalystFiltration Volume (m3) 3.678173287 1 $ 298,689.22
CoolingWater Area (m2) 23.87373533 2 $ 60,863.27
Vertical Vessel Mass (kg) 14070.59392 1 $ 125,768.02
Horizontal Vessel Mass (kg) 14070.59392 1 $ 380,960.15
Pumps/compressors Power (kW) 500 1 $ 1,412,553.21
EDC Vessel HeadColumn Mass (kg) 14656.67719 1 $ 214,166.24
Distillation PackingHeadColumn Volume (m3) 107.405584 1 $ 974,705.67
Vessel High-boilsColumn Mass (kg) 5909.873075 1 $ 109,256.50
Tray of High-boilsColumn Diameter (m) 2.9 14 $ 119,629.89
Vessel VacuumColumn Mass (kg) 987.2355475 1 $ 38,828.86
Trays of VacuumColumn Diameter (m) 1.6 8 $ 15,250.51
H.E Head Column Area (m2) 23.87373533 3 $ 91,294.90
H.E High-boils+VacuumCol Area (m2) 24.79641599 6 $ 183,269.04
EDC Heat Exchanger Area (m2) 37.65408623 4 $ 128,804.60
Cracking Vessel of QuenchColumn Mass (kg) 7389.440934 1 $ 128,103.92
Trays of QuenchColumn Diameter (m) 2.3 27 $ 93,574.51
Vertical Vessel Mass (kg) 7389.440934 1 $ 128,103.92
Horizontal Vessel Mass (kg) 7389.440934 1 $ 70,411.79
CrackingFurnace Duty (MW) 14.25776333 1 $ 993,413.91
EDC Evaporator Duty (kW) 839 1 $ 1,521,799.94
EDC cracker feedpump Volume Flowrate (lit/s) 14.968536 1 $ 10,740.77
VCM Vessel of HCl Column Mass (kg) 594.9910627 1 $ 58,457.12
Distillation Trays of HCl Column Diameter (m) 0.4 50 $ 18,237.53
Vessel of VCMColumn Mass (kg) 2794.226778 1 $ 139,482.88
Packingof VCMColumn Volume (m3) 14.156376 1 $ 128,469.11
Vessel of HCl Stripper Mass (kg) 1195.932036 1 $ 82,557.01
Packingof HCl Stripper Volume (m3) 6.058944 1 $ 19,994.52
H.E of HCl Column Area (m2) 37.65408623 2 $ 64,402.30
H.E of VCMColumn Area (m2) 30.65298463 5 $ 156,410.85
VCMproductpump Volume Flowrate (lit/s) 20.74606659 1 $ 11,676.66
Total Cost (based on 2010) $ 9,292,251.11
Total Cost for 2016 (Fig 7.2/336) $ 11,150,701.34
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VII. ISBL Estimate
Process Cost $ 1,969,352,229.73
Capital Cost $ 11,150,701.34
Land costs, infrastructure, piping, catalysts, maintenance $ 8,920,561.07
fees with construction: insurance, or equipment rental $ 4,460,280.53
ISBL COST TOTAL $ 1,993,883,772.67
VIII. Safety
1. Toxicity
Compound PEL (ppm) LD50 (mg/kg)
Chlorine 1 239
Hydrogen Chlorine 5 4701
2. Flammability
Material Lower Limit Upper Limit
Hydrogen 4.1 74.2
Ethylene 3.1 32
Gasoline 1.3 7
3. Explosivity Properties
Fuel
Maximum Flame
Speed (m/s)
Adiabatic Flame
Temperature (K)
Expansion
Factor
Autoignition
Temperature (◦C)
Hydrogen 22.1 2318 6.9 400
Ethylene 6.5 2248 7.8 490
