Vinyl Chloride Production - Squarespace

Vinyl Chloride Production CHEN 4520 Chemical Process Synthesis December 9th, 2016

Developed for Thomas K. Belval by Group 10

Lucas Karasek Bruce Kirkpatrick Aaron Lipsey Kaela Siahpush

EXECUTIVE SUMMARY This report is first and foremost a comparison of two process units producing vinyl chloride. The baseline process consisted of a direct chlorination followed by thermal cracking; we attempted to design and plan a process to produce the same amount of vinyl chloride more efficiently through an oxychlorinationto-thermal cracking approach. We used Aspen to generate working models of both processes, and saw that adding a recycle to the new oxychlorination process would result in a vastly improved plant. We then conducted several analyses to illustrate our success and were able to successfully demonstrate the improved environmental impact, utility cost, and profitability of our new reaction scheme. We created models of the process units so that they both produced 5250 kg/hr of vinyl chloride, with nearly identical purities (by mass) of 98% for oxychlorination and 97.6% for direct chlorination. It is important that both models have the same capacity, as much of the environmental impact of a process is driven by mass flow (especially when the processes are this similar). With equal mass flows of vinyl chloride, we were able to conduct an environmental assessment of both processes. Using Biwer’s method of environmental assessment, we determined that the increased conversion of hydrogen chloride afforded by the recycle greatly reduced the environmental impact of the process. However, the more important addition may have been the implementation of the 1,2-dichloroethane recycle. The additional recycle stream improved conversion of the pyrolysis reaction to over 99%. By far, the most volatile and hazardous compounds in this process are the intermediate products, and any addition to the process that almost entirely eliminates such products is bound to result in a much smaller environmental impact. We compared the potential profit offered by both processes. The first step in determining the financial viability of each design was to calculate the Total Capital Investment. The oxychlorination process immediately provided savings, with a TCI of $10.5MM compared to $11.76MM for the direct chlorination reaction. Over the production lifetime of the plant, the oxychlorination provides nearly three times the profit, with a cumulative Present Value of $42.26MM after 15 years compared to just $15.41MM for the direct chlorination. We also analyzed utility requirements using the composite curve method, and prepared a stream matching chart. The results showed that the oxychlorination process had smaller hot and cold utility requirements. The oxychlorination process had a hot utility of 5.5  106 kJ/hr compared to of 1.15  107 kJ/hr for direct chlorination. Similarly, oxychlorination needed only 1.54  107 of cold utility compared to 2.5  107 kJ/hr in the direct chlorination process. The resulting heat integration showed why this was the case, as the oxychlorination process was able to match six streams compared to five for the direct chlorination process. When comparing the two processes, the only positive presented by the direct chlorination was the simpler process design (the oxychlorination process has six extra streams). However, this report will demonstrate how an increase in complexity can increase efficiency and profit. This new plant might even allow our group to ascend beyond vinyl chloride, to the high stakes polyvinyl chloride business!

Table of Contents Executive Summary ...........................................................................................................................................................................2 Objective ...........................................................................................................................................................................................4 Design Basis.......................................................................................................................................................................................4 Direct Chlorination Process Design ....................................................................................................................................................1 Direct Chlorination Simulation Development Summary .................................................................................................................................... 2

Oxychlorination Process Design.........................................................................................................................................................3 Oxychlorination Simulation Development Summary ........................................................................................................................................ 5

Utility Requirements .........................................................................................................................................................................6 Direct Chlorination Composite Curve ................................................................................................................................................................ 6 Oxychlorination Composite Curve .................................................................................................................................................................... 6 Utilities Summary ............................................................................................................................................................................................. 7 Direct Chlorination ................................................................................................................................................................................................. 7 Oxychlorination ...................................................................................................................................................................................................... 7 Comparison ............................................................................................................................................................................................................ 7

Environmental Sustainability Assessment .........................................................................................................................................7 Biwer’s Method Overview ................................................................................................................................................................................ 7 Environmental Analysis .................................................................................................................................................................................... 8

Financial Sustainability Assessment ..................................................................................................................................................9 Equipment Costs .............................................................................................................................................................................................10 Equipment Sizing .............................................................................................................................................................................................10 Bare-Module Costing .......................................................................................................................................................................................11 Total Capital Investment .................................................................................................................................................................................11 Total Production Cost ......................................................................................................................................................................................12 Profitability Analysis .......................................................................................................................................................................................13 Return on Investment and Payback Period .......................................................................................................................................................... 13 Net Present Value (NPV) and Investor’s Rate of Return (IRR) .............................................................................................................................. 13 Summary of Profitability Analysis ........................................................................................................................................................................ 14

Direct Chlorination Net Present Value Sensitivity Analysis .............................................................................................................. 15 Bibliography .................................................................................................................................................................................... 16 Appendices ...................................................................................................................................................................................... 18 Appendix A: Process Design.............................................................................................................................................................................18 Reaction Schemes – Direct Chlorination .............................................................................................................................................................. 18 Reaction Schemes – Oxychlorination ................................................................................................................................................................... 19 Process Motivation .............................................................................................................................................................................................. 20 Modeling .............................................................................................................................................................................................................. 21 Appendix B: Stream Matching Diagrams..........................................................................................................................................................22 Direct chlorination ............................................................................................................................................................................................... 22 Oxychlorination .................................................................................................................................................................................................... 23 Appendix C: Environmental Sustainability .......................................................................................................................................................24 Environmental Factor Tables – Direct Chlorination ............................................................................................................................................. 25 Environmental Factor Tables – Oxychlorination .................................................................................................................................................. 27 Biwer Rating Rationale – Direct Chlorination ....................................................................................................................................................... 31 Biwer Rating Rationale – Oxychlorination ............................................................................................................................................................ 32 Appendix D: Financial Sustainability ................................................................................................................................................................33 Estimate of Total Capital Investment ................................................................................................................................................................... 33 Estimate of Total Production Costs ...................................................................................................................................................................... 34 Profitability .......................................................................................................................................................................................................... 35 Sensitivity of IRR................................................................................................................................................................................................... 37 Cost Sheet for Direct Chlorination Model ............................................................................................................................................................ 38 Cost Sheet for Oxychlorination Model ................................................................................................................................................................. 39

OBJECTIVE The primary objective of this project is to develop a well-conceived design of an oxychlorination process with the capacity to produce a total of 40 million kilograms of vinyl chloride per year (5,000 kg/hr for 8,000 hr/year). In order to maintain a standard of quality that will keep the plant profitable, we must deliver a product that is at least 95% pure. During the development of the process design, we are constantly striving to minimize environmental impact and financial risk, while maximizing safety and efficiency. To accomplish this, we will design an oxychlorination process that is superior to the baseline direct chlorination process and is more sustainable than the baseline process (USA Patent No. 2929852, 1950; UK Patent No. 938824, 1963). Our plan to design such a process focuses on limiting the amount of HCl exiting the oxychlorination process. This will not only reduce our environmental impact by reducing the amount of caustic HCl leaving our system, but also make the plant more profitable by increasing the conversion of the same component. We will implement Biwer’s method (Biwer, 2004) of environmental assessment to monitor sustainability and compare the relative environmental impacts of the two processes. In order to determine financial sustainability, we will conduct Total Capital Investment and cash flow analyses. These methods require extensive sizing and pricing data, which will be acquired via both a rigorous simulation and literature consultation. By the end of this report, we will have provided a detailed and comprehensive plan for producing vinyl chloride at a reasonable rate of return. Vinyl chloride is not itself a useful product (Armstrong, 2014). It’s a commodity chemical, as its primary use is as a precursor of polyvinyl chloride plastics. The fact that we are not actually producing an end-product means that there are several objectives that we may want to set for ourselves after constructing our new vinyl chloride plant. First, there is the obvious wasted profit potential of manufacturing our own PVC. Instead of selling our supply of a high purity, low cost vinyl chloride to other manufacturers, we could simply re-invest that capital in our own plant for even greater returns. Furthermore, now that we’re expanding our floor plan anyway, there are myriad products that could utilize spare HCl. Even with the recycle, there is a great deal of unreacted HCl leaving our process; valuable capital simply being flushed away (Santos, 2014)!

DESIGN BASIS 1. The plant needs to make 5,000 kg/hr of vinyl chloride for 8000 hr/yr 2. The process is continuous 3.

Plant has 3 year start up time

4.

Plant has a 15 year production run

5.

Selling price of vinyl chloride = 1200 $/metric ton

6.

Plant runs at 90% capacity after start-up

7.

Income tax rate = 40%

8. There is no need to purchase land 9. The existing utilities supporting direct chlorination processing units have enough extra capacity to cover the needs of the oxychlorination processing unit. 10. The warehouse, QC lab, and staff facilities have enough space to cover the needs of the new processing unit 11. Thermal cracking reaction has approx.. 65% conversion

12. Oxychlorination column design recycles 1,1,2trichloroethane and 1,4-dichlorobutane entirely (negligible amounts of these compounds exist in the outlet streams) 13. SRK Thermodynamic Package (Pro/II, 1992) 14. Cash reserves accounted for 8.33% of the annual cost of manufacture. 15. Inventory amounted to 1.92% of annual sales of liquid and solid products 16. Accounts receivable amounted to 8.33% of all annual sales. 17. Accounts payable amounted to 8.33% of annual feedstock costs. 18. Decanter estimated as a horizontal pressure vessel in model 19. ∆Tmin at pinch point = 10 20. Both direct and oxy chlorination reactors treated as PFRs

DIRECT CHLORINATION PROCESS DESIGN The direct chlorination method of vinyl chloride production begins with its namesake: the direct chlorination of ethylene to produce 1,2-dichloroethane. Ethylene and chlorine (streams 1 and 2) are fed in stoichiometric amounts at 25°C and 1 atm to a 1.5 atm bubble column reactor (R-100) that circulates the reactant gases via sparger dispersion through liquid 1,2-dichloroethane that is maintained at 90°C by a cold water stream (E-100). The bubble column reactor design maximizes ethylene mass transfer and its use in industry is well-characterized (Orejas, 2001). The product stream exiting the direct chlorination reactor is a 97% pure 1,2-dichloroethane stream (stream 3) with limited side reaction and unreacted feed compounds (see Appendix A for a thorough description of process unit designs and a discussion of the various reactions and kinetics involved with this system). R-100 also contains ferric chloride that acts as a Lewis acid catalyst, polarizing chlorine to increase its electrophilic activity and encourage attack on ethylene’s double bond (Wachi & Asai, Kinetics of 1,2Dichloroethane Formation from Ethylene and Cupric Chloride, 1994). The 1,2-dichloroethane stream is joined by a recycle (producing stream 4) and fed through a centrifugal pump (P-100; stream 5) and a fired-heat evaporator (E-101; stream 6) to achieve pressurization to 26 atm, complete vaporization, and a temperature increase to 500°C. This stream is flown into a pyrolysis furnace at the same temperature and pressure, where it is primarily converted to vinyl chloride. Although a catalytic pyrolysis method exists, similar conversion levels can be reached without a catalyst, making the non-catalytic approach a simpler, less expensive, and more favorable method (Dreher, Torkelson, & Beutel, 2012; Rus, 2013). The furnace contents are transferred to a quench tank (V-100; stream 7), which is maintained at 6°C and 12 atm by

Figure DC.1 – EFD for direct chlorination process. Numbered streams correspond to Table DC.1.

circulating the liquid condensate exiting the pyrolysis furnace through a refrigerant-cooled condenser system (P-101, E-102). The quench tank is a vital component of this process: Without rapid cooling the pyrolysis reaction will continue, degrading desirable vinyl chloride and producing additional unwanted side products. The quench contents are fed to a 7-stage distillation column above stage 2 at 12 atm (T-100; stream 8) where HCl is recovered at 97% purity in the distillate (stream 9) and the remainder of the pyrolysis products are fed in the bottoms stream to a second, similar, 9-stage distillation column above stage 3 at 4.8 atm (T-101; stream 10). This column yields a 97.6% pure vinyl chloride stream in the distillate (stream 11) and the 1,2-dichloroethanerich bottoms stream is recycled ahead of the centrifugal pump (stream 12).

Figure DC.2 – PFD for direct chlorination process. Mass flow rates and utility values generated by Aspen Plus.

Direct Chlorination Simulation Development Summary Aspen Plus was used to design and simulate the baseline direct chlorination process. Briefly, the direct chlorination reactor was sized using the formation kinetics of 1,2-dichloroethane and 1,1,2-trichloroethane (Wachi & Morikawa, Liquid-Phase Chlorination of Ethylene and 1,2-Dichloroethane, 1996) and the temperature and pressure shown in the conceptual process PFD. These conditions produced an ethylene conversion of approximately 98%, which is conservatively in agreement with literature (Benyahia, 2005). Pumps and coolers were sized based on stream requirements given in the conceptual PFD. The pyrolysis furnace was modeled as a catalyst-packed PFR with shell-and-tube innards, which is a very typical furnace design for these simulations (Dreher, Torkelson, & Beutel, 2012). The furnace included several reaction sets that required complex rate law modeling (Dimian & Bildea, 2008); the model resulted in an approximate 60% single-pass conversion of 1,2-dichloroethane, which is also in agreement with literature. The quench was modeled as a refrigerant-cooled circulating vessel in accordance with the conceptual PFD. The columns were modeled with RadFrac distillation towers, allowing for realistic simulation based on volatility and desired distillate flowrate. Column T-100 was run at a reflux ratio of 0.8 and a boilup ratio of 1.25 and column T-101 was run at a reflux ratio of 0.9 and a boilup ratio of 1.90. The recycle line results in a 98.6% 1,2-dichloroethane multipass conversion, which is similar to reported literature values. See Appendix A for an in-depth discussion of the modeling process.

Table DC.1 – Stream summaries for direct chlorination process. Stream Number Temperature (°C) Pressure (Atm) Vapor fraction Mass flow (kg/hr) Molar flow (kmol/hr) Component molar flow (kmol/hr): Ethylene Chlorine 1,2-dichloroethane Hydrogen chloride 1,1,2-trichloroethane Vinyl chloride 1,4-dichlorobutane = Stream Number Temperature (°C) Pressure (Atm) Vapor fraction Mass flow (kg/hr) Molar flow (kmol/hr) Component molar flow (kmol/hr) Ethylene Chlorine 1,2-dichloroethane Hydrogen chloride 1,1,2-trichloroethane Vinyl chloride 1,4-dichlorobutane

1

2

3

4

5

6

25 1 1 2,500 86

25 1 1 6,000 86

90 1.5 0.11 8,500 87

94.5 1.5 0.14 14,000 142

181.9 26 0 14,000 142

242 26 1 14,000 142

85.9 0 0 0 0 0 0

0 85.9 0 0 0 0 0

1.3 0.9 84.2 0.4 0.4 0 0

1.3 0.9 137.2 0.4 2.2 0 0.1

1.3 0.9 137.2 0.4 2.2 0 0.1

1.3 0.9 137.2 0.4 2.2 0 0.1

7

8

9

10

11

12

500 26 1 14,000 225

6 12 0 14,000 225

-21.3 12 1 3,250 86

94.2 12 0 10,750 139

30.8 4.8 0 5,250 84

144.5 4.8 0 5,500 55

1.3 0.3 54.2 84.1 1.7 83.1 0.1

1.3 0.3 54.2 84.1 1.7 83.1 0.1

1.3 0 0 83.6 0 1.1 0

0 0.3 54.2 0.6 1.7 82 0.1

0 0.3 1.2 0.6 0 82 0

0 0 53 0 1.7 0 0.1

The stream summary table shows the individual component mole flows, allowing for closer inspection of the material balances. Conveniently, our column design recycles 1,1,2-trichloroethane and 1,4-dichlorobutane entirely (negligible amounts of these compounds exist in the outlet streams, 9 and 11). Additionally, the simulation yields 5,125 kg/hr of vinyl chloride, which translates to an 95.4% overall conversion of feed ethylene to outlet vinyl chloride.

OXYCHLORINATION PROCESS DESIGN The oxychlorination process design is highly comparable to the direct chlorination method, with many shared downstream operations (Benyahia, 2005). It begins with preheated (from storage at 25°C) near-stoichiometric feeds of pure ethylene, oxygen, and hydrogen chloride (streams 1,2, and 3; stream 3 joins with a recycle stream to form stream 4) entering an oxychlorination reactor (R-200). Oxychlorination reactors are gas phase reactors, which avoid corrosion by aqueous acid solutions (a classic pitfall of direct chlorination reactors) (Magistro & Cowfer, 1986). To maintain a vapor fraction of 1, the reactor is held at 260°C and 10 atm. The oxychlorination products (stream 5) are flown to a decanter (D-200), which removes gas (stream 6) and water (stream 7). The bottoms stream from the decanter, stream 8, is joined by a recycle (to form stream 9) before entering a centrifugal pump and heating system in preparation for pyrolysis (F-200; streams 10 and 11).

As with the direct chlorination method, the pyrolysis furnace runs at 500°C and 26 atm before opening into a quench tank (V-200; stream 12) at 12 bar and 6°C. The quench tank temperature is maintained by continuous material circulation in contact with a refrigerant stream. After cooling, the products travel to distillation columns that are essentially identical to those in the direct chlorination process (T-200 and T-201; streams 13 and 15), which one major deviation. In the oxychlorination model, the distillate HCl from T-200 (stream 14) is recycled upstream to enter the oxychlorination reactor alongside the pure components. Similar to the direct chlorination process, the distillate from T-201 (stream 16) is 98% pure vinyl chloride at 13°C and 4.8 atm while the bottoms (stream 17), which is primarily water and 1,2-dichloroethane, is recycled to merge with the enriched 1,2dichloroethane exiting the bottom of the decanter.

Figure OC.1 – EFD for oxychlorination process. Numbered streams correspond to Table OC.1.

Figure OC.2 – PFD for oxychlorination process. Mass flow rates and utility values generated by Aspen Plus.

Oxychlorination Simulation Development Summary Aspen Plus was also used to design and simulate the oxychlorination process. Briefly, the oxychlorination reactor was sized using the formation kinetics of 1,2-dichloroethane and 1,1,2-trichloroethane (Wachi & Morikawa, Liquid-Phase Chlorination of Ethylene and 1,2-Dichloroethane, 1996; Moreira & Pires, 2010) and the temperature described in literature (Moreira & Pires, 2010). These conditions produced an ethylene conversion of approximately 97%, which is conservatively in agreement with literature (Benyahia, 2005; Magistro & Cowfer, 1986). Pumps and coolers were sized based on stream requirements, as the downstream process (outside of the recycles) is the same as in the direct chlorination model. For an extensive discussion of this process, its unit operations, the reactions involved, and the modeling scheme, see Appendix A. Table OC.1 – Stream summaries for oxychlorination process. Stream Number Temperature (°C) Pressure (Atm) Vapor fraction Mass flow (kg/hr) Molar flow (kmol/hr) Component molar flow (kmol/hr): Ethylene Hydrogen chloride Oxygen 1,2-dichloroethane Water Vinyl chloride Chlorine 1,1,2-trichloroethane 1,4-dichlorobutane Stream Number Temperature (°C) Pressure (Atm) Vapor fraction Mass flow (kg/hr) Molar flow (kmol/hr) Component molar flow (kmol/hr): Ethylene Hydrogen chloride Oxygen 1,2-dichloroethane Water Vinyl chloride Chlorine 1,1,2-trichloroethane 1,4-dichlorobutane

1

2

3

4

5

6

7

8

9

250 10 1 1,500 44

250 10 1 2,500 89

250 9.9 1 3,750 104

120.9 9.9 1 7,250 196

260 10 1 11,250 194

-35.2 1 1 750 13

-35.2 1 0 1,750 85

-35.2 1 0 8,750 96

-8.7 1 0 14,500 164

0 0 44.3 0 0 0 0 0 0

88.5 0 0 0 0 0 0 0 0

0 103.7 0 0 0 0 0 0 0

0.7 194.9 0 0 0 0.8 0 0 0

3.3 16.3 1.3 85.9 86 0.8 0.1 0 0

2.6 8.6 1.3 0 0 0.1 0 0 0

0 0 0 0 84.6 0 0 0 0

0.7 7.7 0 85.9 1.4 0.8 0.1 0 0

0.7 7.7 0 138.7 12.7 3.8 0.1 0.05 0.05

10

11

12

13

14

15

16

17

18

-0.2 26 0 14,500 164

242 26 1 14,500 164

500 26 1 14,500 244

6 12 0 14,500 244

-22.4 12 1 3,500 93

79.1 12 0 11,000 140

13.1 4.8 0 5,250 84

111.4 4.8 0 5,750 67

33.5 4.8 0 5,750 67

0.7 7.7 0 138.7 12.7 3.8 0.1 0.05 0.05

0.7 7.7 0 138.7 12.7 3.8 0.1 0.05 0.05

0.7 91.2 0 53 12.3 86.2 0.05 0.05 0.05

0.7 91.2 0 53 12.3 86.2 0.05 0.05 0.05

0.7 91.2 0 0 0 0.8 0 0 0

0 0 0 53 11.3 85.4 0.05 0.05 0.05

0 0 0 0.1 1 82.4 0.05 0 0

0 0 0 52.8 11.3 3 0 0.05 0.05

0 0 0 52.8 11.3 3 0 0.05 0.05

As before, individual component flows can be viewed in the stream summary table. With our dual-recycle process, we again minimize the amount of harmful side products like 1,4-dichlorobutane and 1,1,2trichloroethane that leave the system. Inside the recycle, the single-pass conversion of HCl across the oxychlorination reactor is roughly 92%; literature predicts conversion values ranging 80-97% (Moreira & Pires, 2010). Adding the 1,2-dichloroethane recycle (stream 17) improved the overall conversion of the desired pyrolysis reaction to over 99%.

UTILITY REQUIREMENTS We calculated the minimum utilities for the plant using the pinch method. This method of heat integration ensures our heat exchanger network will have no heat transferred from a hot stream with a temperature above the pinch point to a cold stream with a temperature below the pinch point. Using the composite curves below, we were able to determine the minimum hot and cold duties of the whole process by finding the difference in the endpoints of the hot and cold composite curves.

Direct Chlorination Composite Curve

Figure UR.1 – Composite curves for direct chlorination process.

Oxychlorination Composite Curve

Figure UR.2 – Composite curves for oxychlorination process.

Utilities Summary Direct Chlorination Heat Exchanger V-100 Quench tank E-104 HCl column reboiler F-100 Pyrolysis furnace E-105 VC column condenser E-103 HCl column condenser R-100 Direct chlorination reactor E-106 VC column reboiler E-101 Evaporator F-100 Pyrolysis furnace

Table UR.1 – Utilities summary for direct chlorination process. Type

Base Duty [kJ/hr]

Hot Inlet Temperature [C]

Hot Outlet Temperature [C]

Cooler Heater Cooler Cooler Cooler Cooler Heater Heater Heater

-1.22E+07 3.53E+06 -9.83E+04 -3.22E+06 -1.39E+06 -1.75E+07 3.10E+06 4.23E+06 6.42E+03

500 125 500 42.8 2.9 90 175 280 3000

6 124 499.5 30.8 -21.3 89.5 174 250 2999

Oxychlorination Heat Exchanger V-200 Quench tank E-203 HCl column reboiler E-205 VC column reboiler F-200 Pyrolysis furnace F-200 Pyrolysis furnace E-204 VC column condenser E-202 HCl column condenser R-200 Oxychlorination reactor E-206 Recycle cooler F-200 Pyrolysis furnace

Cold Inlet Temperature [C] Cold Outlet Temperature [C] -25 76.3 249 20 -25 30 144 181.9 500

-24 94.2 250 25 -24 35 144.5 242 500.5

Table UR.2 – Utilities summary for oxychlorination process. Type

Base Duty [kJ/hr]

Cooler Heater Heater Heater Cooler Cooler Cooler Cooler Cooler Heater

1.29E+07 3.37E+06 3.07E+06 1.03E+07 1.68E+04 3.72E+06 1.12E+06 1.98E+07 8.13E+05 6.60E+03

Hot Inlet Temperature [C] 500 125 125 1000 500 31.9 -0.2 260 132.4 3000

Hot Outlet Temperature [C] 6 124 124 400 499.5 13.1 -22.4 259.5 33.5 2999

Cold Inlet Temperature [C] -25 41.8 74.5 242 249 -25 -40 249 20 500

Cold Outlet Temperature [C] -24 79.1 111.4 500 250 -24 -39 250 25 500.5

Comparison The total hot utility requirements for the oxychlorination process amounts to 5.5  106 kJ/hr and a total cold utility of 1.54  107 kJ/hr. The direct chlorination process requires a hot utility of 1.15  107 kJ/hr, and a cold utility of 2.5  107 kJ/hr, indicating that the oxychlorination process is much more efficient with energy. The operation in both processes that required the most cooling utility was the cooling of the stream as it exits the final pyrolysis reactor (when the hot stream cools from 500°C to 6°C. The stream matching (see Appendix B), which was performed by Aspen, shows how the integration differs between the two processes. Mainly, there is an extra cold stream to match for the oxychlorination process. This additional heat sink explains the much lower cold utility for the oxychlorination process.

ENVIRONMENTAL SUSTAINABILITY ASSESSMENT Biwer’s Method Overview When developing a process design, the environmental impact of the reactant and product materials must be taken into account. Determining the environmental impact of a process will ensure that a facility abides by governmental regulations and does not produce unnecessary risk for employees. The method for assessing environmental sustainability that we applied was developed by Biwer et al. (2004). Biwer’s method is aimed at shortening the amount of time it takes to assess the environmental impact and sustainability during the development of a process. This method is only applicable during early stage process development for conceptually comparing processes.

Biwer’s method uses 14 environmental impact categories to classify each compound in the process, which vary depending on whether the component is an input or output of the process. All of the reaction components are classified as input or output components. Then each component is rated for its environmental relevance to each applicable impact category. These impact categories are assigned an environmental impact rating, which is an alphabetical rating of each group corresponding to numerical defined by Biwer (A=1, B=0.3, C=0). These ratings represent the weight of impact that the compound has on each group. Once rated, the 14 impact categories are divided into their designated impact groups, where the rating of each impact group is the same as the highest, most extreme impact rating of the categories in that group. This practice ensures a conservative estimate of environmental impact. Each alphabetical rating correlates to a distinct numerical value, which is used in conjunction with the input or output component’s mass flow to calculate the environmental factors. For input components the impact categories are: Raw Material Availability (Avb), Complexity of Synthesis (CS), Critical Materials Used (CM), Thermal Risk (ThR), Acute Toxicity (AT), Chronic Toxicity (ChT), and Endocrine Disruption (ED). The impact categories for output components are Thermal Risk (ThR), Acute Toxicity (AT), Chronic Toxicity (ChT), Endocrine Disruption (ED), Global Warming Potential (GWP), Ozone Depletion Potential (ODP), Acidification Potential (AP), Photochemical Ozone Creation Potential (POCP), Odour (Od), Eutrophication Potential (EP), and Organic Carbon Pollution Potential (OCPP). Each component’s impact category is given an A, B or C rating based on the scientific relevance and intensity of the compound’s effect. The next step is to assign the impact categories to one of six impact groups: Resources, Grey Input, Component Risk, Organisms, Air, or Water/Soil. How impact categories are grouped into impact groups is shown in Appendix C. Once each component’s impact categories are placed into their respective impact groups, the impact groups are given the highest rated impact letter of that group. For example, if an impact group had three categories, with two Cs and one A, the impact group would be assigned a rating of A. The arithmetic average of all of the component’s impact ratings is the component’s Environmental Factor Value (EF). The Environmental Index (EI) of each component is the EF multiplied by the ratio of component mass flow rate to desired product mass flow rate. The total Environmental Index of the process (EIproc) is calculated by taking the sum of the EI components (EIcomp) involved in the process (inputs and outputs).

Environmental Analysis To assess the environmental impact of the chemicals involved in the production of vinyl chloride, we calculated the Environmental Index of each process using Biwer’s Environmental Factor Method. The total EIproc of any components that appeared in both the inlet and outlet streams was calculated by summing the EIcomp values. This method ensures a conservative estimate when dealing with environmental impact, hopefully precluding the possibility of an environmental disaster. To identify the highest impact compounds, we look for the components with the highest EIcomp values. For both the direct chlorination and oxy-chlorination processes, vinyl chloride was the highest impact component. The other high impact molecules were hydrogen chloride, and chlorine, which was only present in the direct chlorination process. Prior to adding the hydrogen chloride recycle, the oxychlorination process had a higher environmental impact than direct chlorination. After installing the recycle, the resulting lack of waste dropped the environmental impact of the oxychlorination process lower than that of the direct chlorination.

Table ES.1 – Component EI fraction values for direct chlorination process. Input

Total

Component

EI of Component

Ethylene Chlorine Total input

0.226 0.371

EI of Input

EI fraction

Component

EI of Component

0.60

0.378 0.622 1.000

Ethylene 1,2-dichloroethane Vinyl chloride Hydrogen chloride Chlorine Total process

0.231 0.015 0.650 0.293 0.374

Output Component Ethylene 1,2-dichloroethane Vinyl chloride Hydrogen chloride Chlorine Total output

EI of Component 0.005 0.015 0.650 0.293 0.003

EI of Output

0.965

EI fraction 0.005 0.015 0.674 0.303 0.003 1.000

EI of Process

EI fraction

1.56

0.148 0.009 0.416 0.187 0.239 1.000

*For compounds used in both reactions or compounds that enter and exit, the highest EI of component was used to calculate the conservative estimate of the EI of the process

Table ES.2 – Component EI fraction values for oxychlorination process. Input

Total

Component

EI of Component

Ethylene Hydrogen chloride Oxygen Total input

0.226 0.411 0.021

EI of Input

EI fraction

Component

EI of Component

0.658

0.344 0.624 0.033 1.000

Ethylene 1,2-dichloroethane Oxygen Water Vinyl chloride Hydrogen chloride

0.235 0.001 0.022 0.000 0.650 0.441

EI of Output

EI fraction

Total process

0.69

0.013 0.002 0.941 0.043 0.000 0.000 1.000

Output Component

EI of Component

Ethylene 1,2-dichloroethane Vinyl chloride Hydrogen chloride Water Oxygen Total output

0.009 0.001 0.650 0.030 0.000 0.000

EI of Process

EI fraction 0.174 0.001 0.016 0.000 0.482 0.327

1.35

1.000

These asterisk comments aren’t

*For compounds used in both reactions or compounds that enter and exit, the and were a formatting highest EI of componentaccurate was used to calculate the conservative estimate of the EI of the process error

The EI tables show that, from an environmental standpoint, the oxychlorination process is a superior method of producing vinyl chloride than direct chlorination. The EIproc of direct chlorination came to 1.64, compared to the oxychlorination EIproc of 1.35. Appendix C shows that since the two processes have very similar compounds, mass flow has the largest effect on total environmental impact of the process. Adding the recycle greatly reduced the mass of hydrogen chloride leaving the oxy-chlorination process, and thus greatly reduced the overall environmental impact.

FINANCIAL SUSTAINABILITY ASSESSMENT Both the baseline and modified plants were modeled as continuous fluids processes operating at moderate capacity. Using various estimation methods and guidelines for the cost of equipment, the total capital investment and total production were defined. Profitability metrics were assessed and discussed to determine which process was more financially sustainable. Further detail regarding the estimation of costs and profitability metrics such as return on investment, payback period, net present value, and the investor’s rate of return can be found in Appendix D.

Equipment Costs Given that a pre-optimized process design (the baseline concept) was provided for direct chlorination, a preliminary estimate based on the Individual Factors Method was carried out for each process (Guthrie, 1974). The purchase costs of major process equipment were used in estimating the total capital investment. Equipment List for Direct Chlorination Process (Including Purchase Costs)

Equipment Name Direct chlorination reactor and reactor condenser Reactor centrifugal pump Evaporator Pyrolysis furnace Quench tank HCl column VC column HCl column condenser VC column condenser HCl column reboiler VC column reboiler HCl column reflux drum VC column reflux drum

Equipment Label

R-100 / E-100

P-100 E-101 F-100 V-100 / P-101 / E-102 T-100 T-101 E-103 E-105 E-104 E-106 E-103 E-105

Material of Construction

Stainless Steel Cast Steel Carbon Steel Stainless Steel Stainless Steel Carbon Steel Carbon Steel Stainless Steel Stainless Steel Stainless Steel Stainless Steel Carbon Steel Carbon Steel

Size

2.5 ft diam / 11.5 ft height 372 hp 400 ft2 1727 ft2 480 ft2 2.5 ft diam / 28 ft height 3 ft diam / 32 ft height 336 ft2 337 ft2 201 ft2 491 ft2 3 ft diam / 6 ft height 3 ft diam / 9 ft height

Design Pressure (psig)

35 367 273 417 187 187 81 187 81 187 81 187 81

C P , f.o.b. Purchase Cost (MS Index = 596)

$

45,810.85

$

106,674.54

$

97,245.81

$

294,996.08

$

76,959.49

$

63,114.24

$

76,899.62

$

95,753.03

$

93,616.91

$

38,025.01

$

45,496.75

$

26,645.07

$

21,803.16

(Note that the reactor condenser (E-100) is included in the pricing of R-100 and consists of circulating cold water to maintain the reaction temperature in the forming 1,2-dichloroethane.)

The major equipment for the direct chlorination process consists of a centrifugal pump, evaporator, a direct chlorination reactor, condenser, pyrolysis furnace, and two distillation columns. The modified baseline process includes the same components along with a decanter as well as an additional condenser. Sizing information was obtained from Aspen Plus, and the equipment price values were determined using purchase cost equations found in Chapter 22 of Seider and Seader (S&S). Below is an equipment table listing pertinent information on major process equipment. To update the purchase costs, recent Marshall and Swift index values were incorporated in the table (Seider, Seader, Lewin, & Widagdo, 2009). More detailed guidelines on the deriving the purchase cost for various equipment can be found in Appendix D.

Equipment Sizing Using the volumetric flow rate and pump head information, a cast steel centrifugal pump was selected to ensure proper compression in the chemical process. Using the heat transfer surface area, the cost of the evaporator

and condenser were approximated. The pyrolysis furnace was costed using the heat duty provided in Aspen Plus. The decanter was estimated as a horizontal pressure vessel given the diameter, length, and weight of the tank from the simulation model. For reactor sizing, both direct chlorination and oxy-chlorination reactors were treated as plug flow reactors (PFRs). Each plug flow reactor can be approximated as a pressure vessel. Using diameter, length, and weight values from Aspen Plus, each reactor was sized and costed appropriately. Using the inside diameter and tangent-to-tangent length data from Aspen Plus, the cost of each distillation tower was estimated. Sieve trays were used along with Carbon steel to construct each tower. The condensers and reboilers were costed as Kettle vaporizer and U-tube heat exchangers, respectively. Each reflux drum was estimated as a horizontal pressure vessel and constructed from Stainless steel.

Bare-Module Costing After outlining the necessary equipment costing information, the bare-module cost from Guthrie’s method was determined. Using the appropriate bare-module factor, FBM, and multiplying it by each purchase cost, a baremodule cost, CBM, was determined. Bare-module factors for various processing equipment can be found in Table 22.11 of S&S. These factored costs account for delivery, insurance, taxes, and direct materials and labor for installation (Verwijs, 1995). The total bare-module cost, CTBM, was obtained by summing the bare-module costs of the processing equipment. This amount was used in finding the total capital investment of each chemical process. Capital Cost Estimate of Bare-Module Equipment Cost for a Vinyl Chloride Plant - Costs in Millions of U.S. Dollars Direct Chlorination Process Fabricated Equipment Heat Exchangers Pressure Vessels Distillation Columns Pyrolysis Furnace Reactors Process Machinery Pumps Total bare-module cost for on-site equipment

Cp

FBM

CBM

0.45 0.08 0.14 0.29 0.16

3.17 3.05 4.30 2.19 4.16

1.42 0.24 0.60 0.65 0.68

0.11

3.30

0.35

3.93

Oxychlorination Process Fabricated Equipment Heat Exchangers Pressure Vessels Distillation Columns Pyrolysis Furnace Reactors Process Machinery Pumps Total bare-module cost for on-site equipment

Cp

FBM

CBM

0.49 0.08 0.13 0.32 0.05

3.17 3.05 4.3 2.19 4.16

1.55 0.24 0.57 0.71 0.19

0.02

3.3

0.05

3.31

Total Capital Investment The total capital investment (TCI) provides an in-depth look at the costing necessary to deliver the product, calculated as a one-time investment in chemical plant startup. This vinyl chloride plant was modeled as an addition to an existing integrated complex. A TCI table was created based on Table 22.9 of S&S (Seider, Seader, Lewin, & Widagdo, 2009). The formulas and estimates used in creating the table can be found in the appendix.

As an addition to an existing complex, no land purchase costs were necessary (with the exception of site preparation). Storage tanks for raw materials were considered and the existing utilities will support the need of installed processing unit, negating the need for allocated costs (Bureau, 2015). Service facilities were also accounted for and the cost of the computers, software, and associated items are included within the total baremodule cost for on-site equipment. Total Capital Investment for Vinyl Chloride Plant - Cost in Millions of U.S. Dollars ($MM/yr) Total bare-module costs for on-site equipment Total bare-module costs for spares Total bare-module costs for storage and surge tanks Total bare-module costs for comupters and software, including distributed control systems, instruments, and alarms Total bare-module investment, TBM Cost of site preparation Cost of service facilities Allocated costs for utility plants and related facilities Total of direct permanent investment, DPI Cost of contingencies and contractor's fee Total depreciable capital, TDC Cost of plant startup Total permanent investment, TPI Working capital Total capital investment, TCI

Direct Chlorination Process 3.93 0.11 0.58 4.62 0.18 0 0 4.80 0.86 5.67 0.57 6.23 5.52 11.76

Total Capital Investment for Vinyl Chloride Facility - Cost in Millions of U.S. Dollars ($MM/yr) Total bare-module costs for on-site equipment Total bare-module costs for spares Total bare-module costs for storage and surge tanks Total bare-module costs for comupters and software, including distributed control systems, instruments, and alarms Total bare-module investment, TBM Cost of site preparation Cost of service facilities Allocated costs for utility plants and related facilities Total of direct permanent investment, DPI Cost of contingencies and contractor's fee Total depreciable capital, TDC Cost of land Cost of royalties Cost of plant startup Total permanent investment, TPI Working capital Total capital investment, TCI

Oxychlorination Process 3.31 0.02 0.50 3.82 0.15 0.00 0.00 3.98 0.72 4.69

0.47 5.16 5.34 10.50

Using the assumptions above, as well as estimates given by S&S, the total capital investment for the baseline process was $11.76 million. The oxychlorination process was similar, estimated at $10.50 million. The increase in efficiency can be attributed to the decrease in cost.

Total Production Cost The total production cost outlines the viability of implementing a new chemical process. Much like Table 23.1 of S&S, a cost sheet has been developed for the baseline as well as modified process (Seader, 2009). The cost sheet for each process can be found in Appendix D, as well as an outline of methods to estimate factors. A basis of 90% capacity for the year is considered when determining cost factors. Additionally, depreciation is modeled as a 10-year straight-line depreciation. Any general expenses have been omitted due to lack of information. From the total production cost, the working capital can be calculated, shown in the previous table of the TCI. The production cost for the direct chlorination process was $39.38 million per year, whereas the modified

process had a total production cost of $24.57 million per year. Although it used more raw materials, the oxychlorination process was more efficient and yielded a lower production cost.

Profitability Analysis To assess the profitability of each process, principal measures such as the return on investment and payback period were analyzed. To observe the feasibility of each process over time, the net present value and investor’s rate of return were determined and compared.

Return on Investment and Payback Period To appropriately measure the “economic goodness” of the vinyl chloride plant, the percent return on investment was developed (Seader, 2009). A capacity of 90% from the first year of production, 40% income tax rate, and $1,200 per metric ton of vinyl chloride was specified. Along with these constants, the total depreciable cost, and total production cost, the annual earnings were determined. Dividing these earnings by the total capital investment yielded a return on investment of 61% per year for the direct chlorination process and 147% per year for the oxychlorination process. The time it took for the annual earnings to equal the original investment was computed. This is commonly called the payback period. Using the total depreciable capital along with the net cash flow, a payback period was estimated. For the baseline process, it will take 0.77 years for the investment to be paid off. For the modified process, the payoff period will take 0.37 years. With rapid development and increasing competition, periods greater than four years should not be considered. Fortunately, both cases are well below this value.

Net Present Value (NPV) and Investor’s Rate of Return (IRR) The net present value sums the cash flows across a plant’s projected life-span. This can provide quantitative data for comparing the required capital against competing processes. For the vinyl chloride plant, a construction period of three years was specified. The total depreciable capital was distributed into three equal parts during construction. Production began at 30% capacity, followed by 60% in the second year and 90% capacity for the remainder of production. After fifteen years of production, the plant will be sold for salvage and the working capital recovered. An interest rate of 15% per year and an income tax rate of 40% per year were used. The depreciation was modeled as a 10-year straight-line depreciation. For the baseline process, the final NPV was $15.41 million. For the modified process, the final NPV was $42.26 million. The next page contains a table of the cash flows in millions of dollars per year for the baseline as well as the modified process. Development of the sheet can be found in Appendix D. Using the same outline for the NPV, the IRR was determined. This is defined as the interest rate which will yield a NPV of zero in the final year. For the baseline process, this was found to be 36.1%. For the modified process, an IRR of approximately 62.0% was found. This is justified by the fact that both cases provided positive final NPVs, so an interest rate higher than the specified 15% will be produced to reach an NPV of zero.

Calculation of Cash Flows (Millions of Dollars) for Vinyl Chloride Plant (Nominal interest rate = 15%) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Year

fC(TDC)

2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033

-1.89 -1.89 -1.89

C(WC)

D

C(Excl. Dep)

S

Net Earnings

Discounted Cash Flow

Cash Flow (PV)

Cum. PV

16.90 33.80 50.70 50.70 50.70 50.70 50.70 50.70 50.70 50.70 50.70 50.70 50.70 50.70 50.70

0.00 0.00 0.00 1.92 4.19 6.45 6.45 6.45 6.45 6.45 6.45 6.45 6.45 6.79 6.79 6.79 6.79 6.79

-1.89 -1.89 -7.41 2.49 4.76 7.02 7.02 7.02 7.02 7.02 7.02 7.02 7.02 6.79 6.79 6.79 6.79 12.31

-1.89 -1.43 -4.87 1.42 2.36 3.03 2.64 2.29 2.00 1.74 1.51 1.31 1.14 0.96 0.83 0.73 0.63 1.00

-1.89 -3.32 -8.19 -6.77 -4.40 -1.37 1.27 3.57 5.56 7.30 8.81 10.12 11.26 12.22 13.05 13.78 14.41 15.41

-5.52 0.57 0.57 0.57 0.57 0.57 0.57 0.57 0.57 0.57 0.57

5.52

13.13 26.25 39.38 39.38 39.38 39.38 39.38 39.38 39.38 39.38 39.38 39.38 39.38 39.38 39.38

Calculation of Cash Flows (Millions of Dollars) for Vinyl Chloride Plant (Nominal interest rate = 15%) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Year

fC(TDC)

2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033

-1.56 -1.56 -1.56

C(WC)

D

C(Excl. Dep)

5.34

8.19 16.38 24.57 24.57 24.57 24.57 24.57 24.57 24.57 24.57 24.57 24.57 24.57 24.57 24.57

Oxychlorination Process

S

Net Earnings

Discounted Cash Flow

Cash Flow (PV)

Cum. PV

16.36 32.72 49.09 49.09 49.09 49.09 49.09 49.09 49.09 49.09 49.09 49.09 49.09 49.09 49.09

0.00 0.00 0.00 4.62 9.52 14.43 14.43 14.43 14.43 14.43 14.43 14.43 14.43 14.71 14.71 14.71 14.71 14.71

-1.56 -1.56 -6.90 5.09 9.99 14.89 14.89 14.89 14.89 14.89 14.89 14.89 14.89 14.71 14.71 14.71 14.71 20.05

-1.56 -1.18 -4.54 2.91 4.97 6.44 5.60 4.87 4.23 3.68 3.20 2.78 2.42 2.08 1.81 1.57 1.37 1.62

-1.56 -2.75 -7.29 -4.38 0.59 7.03 12.63 17.50 21.73 25.42 28.62 31.40 33.82 35.90 37.71 39.28 40.65 42.26

-5.34 0.47 0.47 0.47 0.47 0.47 0.47 0.47 0.47 0.47 0.47

Direct Chlorination Process

Summary of Profitability Analysis After assessing financial sustainability, the modified process concept based on oxychlorination is the more financially attractive of the two models. With comparable capital costs, the direct chlorination process has a substantially higher production cost per year. The modified process outperforms the baseline with a higher return on investment and shorter payback period. The profitability of the final net present value at an interest rate of 15% for the oxychlorination concept is much greater than the baseline concept, at $42.26 million compared to $15.41 million. With a high IRR of 62.0%, the process based on oxychlorination is highly favorable

for implementation. From a financial perspective, efforts focused on generating the greatest profit should construct the modified process concept replacing direct chlorination with oxychlorination.

DIRECT CHLORINATION NET PRESENT VALUE SENSITIVITY ANALYSIS The following plot shows how NPV over 15 years of vinyl chloride production reacts to changes in various factors. The plots all show linear relationships between NPV and change in TCI, capacity, and selling price of vinyl chloride. Looking at the slopes of these graphs and examining their magnitude allows us to assess the sensitivity of profits to each factor. A steeper slope indicates that the factor has a greater effect on NPV, so NPV is more sensitive to that factor. This analysis tells us the degree to which we should be confident in our projections for the future of the plant. Any factors that have a high sensitivity reveal an element of risk that we cannot control, and may even give future investors pause. The chart was prepared with the following data: Table SA.1 – Effect of %TCI, %Capacity, and %Price of vinyl chloride on net present value.

%TCI

NPV

% Capacity

NPV

% Price of VC

NPV

50% 75% 100%

17.31 16.36 15.41

50% 70% 90%

-27.85 -6.22 15.41

50% 75% 100%

-33.25 -8.92 15.41

150%

13.5

150%

64.07

Figure SA.1 – Effect of %TCI, %Capacity, and %Price of vinyl chloride on net present value.

The magnitudes of the slopes show that our model is relatively unscathed by changes in TCI. In order to make this venture unprofitable, we would have to increase our investment by 500%. In comparison, the slopes of the capacity and vinyl chloride price graphs should give us pause. A mere 6% drop in the price of vinyl chloride erases our healthy $15.41M profit. Predictably, any drop in capacity results in a precipitous drop in profit, indicating that changes in capacity have the most severe effect out of the factors we analyzed. In order to break even, the plant must run at least at 75% capacity over the 15 years of production. These projections indicate that it might be prudent to decrease our investment in the production of vinyl chloride, as it offers a decrease in risk at

relatively low cost. Alternatively, to reduce dependence on the price of vinyl chloride, we could invest in a plant that processes the vinyl chloride monomer into PVC plastic. This course of action would completely remove our dependence on the relatively unstable commodity chemical, and place it in a more reliable end-product.

BIBLIOGRAPHY A. W. (2014). Environmental Product Declaration Vinyl Composition Tile. Retrieved from astm.org: http://www.astm.org/CERTIFICATION/DOCS/245.EPD_for_Armstrong_Vinyl_Composition_Tile.pdf B. e. (2004). Environmental Assessment in early process development. Journal of Chemical Technology and Biotechnology, 79: 597-609. B. G. (1963). UK Patent No. 938824. B. o. (2015). Chemical Plant and System Operators. Occupational Employment Wages. Benedict, D. (1950). USA Patent No. 2929852. Benyahia, F. (2005). VCM Process Design. Chemical Engineering Education J, 39:62-67. C. C. (2016). Chemical Data Sheet: Vinyl chloride. Retrieved from cameochemicals.noaa.gov: https://cameochemicals.noaa.gov/chemical/1692 C. e. (1970). Kinetics of the Oxychlorination of Ethylene. Ind. Eng. Chem. Process Des. Develop, 414-419. C. f.-N. (2003). International Chemical Safety Cards: Chlorine- Lung Damaging Agent. Retrieved from cdc.gov: http://www.cdc.gov/niosh/ershdb/emergencyresponsecard_29750024.html C. f.-N. (2014). 1,2-Dichloroethane. Retrieved from cdc.gov: http://www.cdc.gov/niosh/ipcsneng/neng0250.html D. e. (1997). Scale up of chemical reactors. Catalysis Today, 483-533. Dimian, A. C., & Bildea, C. S. (2008). Chemical Process Design: Computer Aided Case Studies Chapter 7. Weinhein: Wiley. Dreher, E. L., Torkelson, T. R., & Beutel, K. K. (2012). Chlorethanes and chloroethylenes. Ullmann’s Encyclopedia of Industrial Chemistry, 719–788. Ghanta, M., Fahey, D., & Subramaniam, B. (2014). Environmental impacts of ethylene production from diverse feedstocks and energy sources. Appl Petrochem Res, 4:167. Guthrie, K. M. (1974). Process Plant Estimating, Evaluation, and Control. Los Angeles: Craftsman Book of America. Magistro, A. J., & Cowfer, J. A. (1986). Oxychlorination of ethylene. Journal of Chemical Education, 63:1056. Moreira, J. C., & Pires, C. A. (2010). Modelling and simulation of an oxychlorination reactor in a fluidized bed. The Canadian Journal of Chemical Engineering, 88:350-358.

N. C. (2004). Compound Summary for CID 6325 ETHYLENE. Retrieved from PubChem: https://pubchem.ncbi.nlm.nih.gov/compound/Ethene#section=Top N. C. (2005). Compound Summary for CID 24526 CHLORINE. OPEN CHEMISTRY DATABASE. O. e. (2014). Calculating the Capacity of Chemical Plants. Reactions and Separations, 59-63. Orejas, J. A. (2001). Model evaluation for an industrial process of direct chlorination of ethylene in a bubblecolumn reactor with external recirculation loop. Chemical Engineering Science, 56:513–522. P. C. (1992). Vinyl Chloride Monomer (VCM) Plant. Simulation Sciences. R. e. (2013). Scaling Up Process Output of Monomer Reactor. Advanced Materials Research, 299-303. Rosen, A. (2014). Reactor Design. S. e. (2014). Development of a method for the identification of organic contaminants in vinyl chloride monomer (VCM) by TD-GC-MS and multivariate analysis. Analytical Methods, 8946-8955. Seider, W. D., Seader, J. D., Lewin, D. R., & Widagdo, S. (2009). Product and Process Design Principles: Synthesis, Analysis, and Design. Hoboken, NJ: John Wiley & Sons. U. D. (2001, 12). Toxicological Profile for 1,2-Dichloroethane. Retrieved from atsdr.cdc.gov: http://www.atsdr.cdc.gov/toxprofiles/tp38.pdf U. D. (2002). Process Equipment Cost Estimation Final Report. U. E. (2000). Health Effects Fact Sheet: Chlorine. U. E. (2000). Health Effects of Vinyl Chloride. Retrieved from epa.gov: https://www.epa.gov/sites/production/files/2016-09/documents/vinyl-chloride.pdf U. E. (2002). Health Effects of Ethylene Dichloride (1,2-Dichloroethane). Retrieved from epa.gov: https://www.epa.gov/sites/production/files/2016-09/documents/ethylene-dichloride.pdf U. I. (2015, 04 25). Material Safety Data Sheet for Gaseous Oxygen. Retrieved from Universal Industrial Gases Inc.: http://www.uigi.com/MSDS_gaseous_O2.html Univeristy, L. S. (n.d.). Ethylene DIchloride Solvent Properties. V. e. (1995). Reactor Operating Procedures for Startup of Continuously-Operated Chemical Plants. Reactors, Kinetics and Catalysis, 148-158. Wachi, S., & Asai, Y. (1994). Kinetics of 1,2-Dichloroethane Formation from Ethylene and Cupric Chloride. Ind. Eng. Chem. Res., 33:259-264. Wachi, S., & Morikawa, H. (1996). Liquid-Phase Chlorination of Ethylene and 1,2-Dichloroethane. Journal of Chemical Engineering of Japan, 19:437-443.

APPENDICES Appendix A: Process Design Reaction Schemes – Direct Chlorination Direct chlorination in a liquid phase of 1,2-dichloroethane involves two primary reactions: C2H4 + Cl2 –(R1) C2H4Cl2

(A1)

C2H4Cl2 + Cl2 –(R2) C2H3Cl3 + HCl

(A2)

Experimentally, R1 has been shown to follow the form R1 = kR1[ethylene][chlorine] and R2 closely follows the form R2 = kR2[ethylene][chlorine]2 (Wachi & Morikawa, Liquid-Phase Chlorination of Ethylene and 1,2Dichloroethane, 1996). The production of 1,2-dichloroethane (A1) can have selectivity approaching 100%, depending on the operating conditions in the reaction vessel. Sparger efficiency plays a major role in improving conversion, since this reaction is somewhat unique: It occurs in a bath of the product material. Chlorine is more soluble than ethylene in 1,2-dichloroethane, and direct chlorination is a liquid-phase reaction so the absorption rate of the reactants is important. Wachi et al. propose experimentally derived kR1 and kR2 values of 0.132 m3 mol-1 s-1 and 0.0239 m6 mol-2 s-1, respectively (which is in alignment with our expectations, since we’re anticipating a high conversion to 1,2dichloroethane). After undergoing a series of temperature, pressure, phase, and component (recycle merges and splits) changes, the 1,2-dichloroethane formed in reaction A1 reaches the pyrolysis reactor and experiences some new reactions: C2H4Cl2 –(R3) C2H3Cl + HCl

(A3)

C2H3Cl –(R4) C2H2 + HCl

(A4)

C2H4Cl2 –(R5) C2H4 + Cl2

(A5)

From (Dimian & Bildea, 2008), we know these reactions can be modeled with the rate model Ri=kici with preexponential factor and activation energy data as follows: Reaction

Pre-exponential factor [s-1]

Activation energy [cal/mol]

A3

1.14 x 1014

58000

A4 A5

5.00 x 1014 1.00 x 1013

69000 72000

As one might expect, the pyrolysis reactor produces some larger side-products (next page).

C2H2 + C2H3Cl –(R6) C4H5Cl

(A6)

2 C2H4Cl2 –(R7) C4H8Cl2

(A7)

Where reactions A3-A5 broke down 1,2-dichloroethane and vinyl chloride into their constituent pieces like acetylene, ethylene, chlorine, and hydrogen chloride, reactions A6 and A7 produce larger molecules like chloroprene (C4H5Cl) and 1,4-dichlorobutane. However, acetylene is required for reaction A6 and it is produced in negligible quantities in reaction A4 in a well-optimized system, so chloroprene flow rates are typically negligible. The conversion of reaction A7 is governed by its selectivity, as stated by (Dimian & Bildea, 2008): Conversion of 1,2-dichloroethane = 1-S = 1-(0.989 + 0.0506X – 0.0652X2) where X is the conversion in reactions A3-A5.

Finally, various tri-chlorine molecules are made in small quantities in the pyrolysis reactor: C2H3Cl + Cl2 –(R8) C2H3Cl3

(A8)

C2H4Cl2 + Cl2 –(R9) C3H3Cl3 + HCl

(A9)

C2H2 + 2 Cl2 –(R10) C2HCl3 + HCl

(A10)

(Dimian & Bildea, 2008) gives chlorine conversions of 50%, 20%, and 30% for A8, A9, and A10, respectively.

Reaction Schemes – Oxychlorination Oxychlorination follows the same scheme as direct chlorination, but it produces 1,2-dichloroethane differently. Instead of a liquid-phase phase reaction (like direct chlorination), the oxychlorination process occurs entirely in the gas phase (Rosen, 2014). An oxychlorination reactor contains a heterogeneous catalyst like CuCl2 to achieve the following reactions: C2H4 + 2 HCl + 0.5 O2 –(R11) C2H4Cl2 + H2O (A11) C2H4Cl2 + HCl + 0.5 O2 –(R12) C2H3Cl3

(A12)

Which are governed by the rate expressions (Carrubba, 1970): R11 = (k11KaCcPC2H4) / (RT + KaPC2H4) R12 = k12PC2H4Cl2 * sqrt(PCl2) These expressions, in combination with the kinetic parameters given in (Moreira & Pires, 2010), allow for rigorous differential modeling of each reactor.

Process Motivation Reactors: When designing our chlorination reactors, we had to make a decision between a fixed-bed reactor or a fluidizedbed reactor. Fixed-bed reactors have catalyst packed in vertical tubes, which provides a large surface area for heat to transfer to a cooling medium. However, the reaction is exothermic, and the fixed bed leads to inconsistent catalyst activity. Fluidized-bed reactors provide a solution to this problem. A fluidized-bed reactor introduces the catalyst as a fine powder. The small particle size ensures that kinetics are close to ideal, which results in a more uniform temperature profile in the reactor. In our case, the fluidized-bed does not serve our purposes, because back-mixing in the fluidized reactor leads to a decrease in efficiency. Since we intend to run the process continuously, decreases in efficiency over time could be fatal from a business standpoint. As such, we used a fixed bed reactor. The reaction conditions differ greatly between the direct and oxychlorination reactors. For direct chlorination, the chlorination takes place exclusively in the liquid phase, and employs a Lewis acid catalyst. The aqueous catalyst is important, as it means that all the reactants are dissolved by the product 1,2-dichlorethane. This can lead to problems with mole flow, as the ethylene being fed to the reactor is less soluble in DCE than chlorine. This means the chlorine will enter solution faster than the ethylene, possibly leading to a buildup of ethylene in the reactor. This offers a stark contrast to the oxychlorination process, which chlorinates in the gas phase, thus avoiding the corrosive problems associated with aqueous acids. In order to facilitate the gas phase reaction, the oxychlorination reactor employs solid cupric chloride, CuCl2 . The cupric chloride is introduced as a fine powder to allow for maximum surface area. Reactor feed: There are decisions to be made about the feed to the reactor as well. Namely, we can feed oxygen to the reaction either as a pure O2 stream, or simply feed the reactor air. Air has the obvious benefit of being cheaper. No one ever has to buy air. Furthermore, the nitrogen in the air stream adds quite a few inert molecules, which allows for greater temperature control. In the end, it is the excess nitrogen that precludes our design from incorporating air based oxychlorination. All that nitrogen can make the stream up to a 100 times larger, making the rest of the process far too expensive. Pure O2 may have an overhead, but greatly improves our yields. However, there is the additional cost associated with the fact that oxygen based oxychlorination requires a higher excess of HCl, which will certainly add to our raw material cost. Quench: The quench is a crucial process unit as it quickly cools the gas coming from the pyrolysis furnace, halting any further pyrolysis and vinyl chloride decomposition. It also serves as the first separation, flushing heavy impurities generated by the furnace out of the system. For more information about the quench, see Modeling.

Decanter: The decanter is a horizontal pressure vessel that acts as a liquid-liquid vapor separator; it was chosen for the efficacy with which it could remove water from a stream. See the Modeling section for more on the decanter. Distillation train: The entire objective of this process is to produce high purity vinyl chloride monomer. Achieving that purity will require a number of separations. Following separation heuristics, the lightest component is the first separation target. In this case of the oxychlorination reactor, the lightest component is HCl. The lightest compound actually must be separated first, due to the high pressure of the stream leaving the pyrolysis reactor. The temperature would be too high at the bottom of the column, where the heaviest components are, which means the heavy key (vinyl chloride) would not be properly separated from the heavy non-key, 1,2-dichloroethane, and would require another separation. Once the first column removes most of the HCl in the distillate, the second column can target the heavy key, vinyl chloride. Our vinyl chloride is condensed in the distillate, while the heavy nonkey 1,2-dichloroethane is taken to be recycled in the bottoms product.

Modeling Reactor modeling: The direct chlorination reactor was modeled as an idealized CSTR (since adding a sparger in Aspen is a seemingly fruitless quest) with near-entire conversion of ethylene to 1,2-dichloroethane. The reactor was held at the bubble point of the mixture such that freshly synthesized 1,2-dichloroethane evaporates and condenses during its residence. Because this reaction (A1 and A2) is very exothermic (∆H = 218 kJ/mol), the flowing 1,2-dichloroethane serves as a temperature mediator. Conversion calculations result in approximately 99.5% conversion to 1,2-dichloroethane and 0.5% conversion to 1,1,2-trichloroethane. The size of the vessel was determined by Aspen and can be viewed in the Equipment Sizing section. (Moreira & Pires, 2010) contains a method by which the reactor can be manually sized through calculating a series of differential equations relating to the height of a rising bubble inside the vessel. The oxychlorination reactor was modeled as a shell-and-tube heat exchanger achieving 98% conversion of ethylene to 1,2-dichloroethane and 0.5% conversion of ethylene to 1,1,2-trichloroethylene and hydrogen chloride. Adding an HCl recycle upstream of the reactor (coming from the first distillation tower) improves both Environmental Impact and system efficiency considerably. Heat exchanger modeling: Heating units were added to streams with the necessary calculated duty to achieve desired stream conditions (see Utilities Summary). Resultant duty values from Aspen Plus were imported into Aspen Energy Analyzer to generate composite curve and stream matching data. See the PFDs in Process Design for specific duties per unit. Calculations performed in the Financial Sustainability Assessment section translate these duty and surface area values into costing information.

Decanter modeling: The decanter was modeled as an equilibrated flash drum with given splits based on known solubility data. Specifically, 1,2-dichloroethane is reported to have 0.81% solubility by mass in water at 20°C and the solubility of water under the same conditions in 1,2-dichloroethane is 0.15% by mass. This data was used to perform what is essentially a LLE calculation to find the splits coming out of the decanter.

Appendix B: Stream Matching Diagrams Direct chlorination

Oxychlorination

Appendix C: Environmental Sustainability

All non-original tables and charts come from (Biwer, 2004). At right is a map of how the impact categories and impact groups were sectioned together, and which categories are used for input or output environmental factors. To calculate the environmental impact of all of the chemicals involved in the reaction, we looked up literature for the factor values from the Environmental Protection Agency, along with other governmental and independent research agencies (CDC, NIOSH, US Human Health and Safety).

These formulas were provided in the paper describing Biwer’s assessment method: They provide the equations to calculate the Environmental Factors and Environment Indices for each component and overall process.

Environmental Factor Tables – Direct Chlorination Input Components

Inlets: Component

Ethylene

Impact Category

Impact Category ABC Rating

Avb

B B B B B B

CS CM AT ChT ED

A

ThR

Impact Group

0.3 0.3

B

0.3

A

1

Impact Group ABC Rating

Impact Group Numerical Rating

C C

0 0

A

1

B

0.3

Organisms Organisms Organisms Component risk

Impact Category


Impact Group

Avb CS CM AT ChT ED

C C C B A C

Resources Grey Input Grey input Organisms Organisms Organisms

Outlets:

B B

Resources

Chlorine

B


Grey Input Grey input

Component

ThR


Component risk

EF Value 0.475

EF Value 0.325

Output Components Component

Ethylene

Impact Category


Impact Group

AT ChT ED ThR

B B B A

Organisms Organisms Organisms Component

GWP

B

Air

ODP AP POCP

B A C

Air Air Air

OD

C

Air

EP

B

Water/soil

OCPP

B

Water/soil



B

0.3

A

1

A

1

B

0.3

EF Value 0.65

Component

1,2 Dichloroethane

Impact Category


AT ChT ED

B A B

ThR

A

GWP ODP AP POCP OD EP OCPP

C C C B C B B

Component

Vinyl Chloride

Impact Category


AT ChT ED

B A B

ThR

A


B B B C B C B

Component

Hydrogen Chloride

Impact Category


AT ChT ED

A B C

ThR

C


C C A C C C C

(Cameo, 2016; U.S., 2001)

Impact Group Organisms Organisms Organisms Component risk Air Air Air Air Air Water/soil Water/soil





A

1

A

1

B

0.3

B

0.3



A

1

A

1

B

0.3

B

0.3



A

1

C

0

A

1

C

0

EF Value 0.65

EF Value 0.65

EF Value 0.5

Component

Chlorine

Impact Category


AT ChT ED

B A C

ThR

B


C C A C B B C

Impact Group


Organisms Organisms Organisms Component risk Air Air Air Air Air Water/soil Water/soil


A

1

B

0.3

A

1

B

0.3

EF Value 0.65

(Center, International Chemical Safety Cards: Chlorine- Lung Damaging Agent, 2003; National, Compound Summary for CID 24526 CHLORINE, 2005; U.S., Health Effects Fact Sheet: Chlorine, 2000)

Environmental Factor Tables – Oxychlorination Inlets: Component

Impact Category

Ethylene Impact Category ABC Impact Group Impact Group Rating ABC Rating


Avb CS CM AT ChT ED

B B B B B B


B B

0.3 0.3

B

0.3

ThR

A

Component risk

A

1

ThR

A

Component risk

A

1



Component

EF Value

0.475

Hydrogen Chloride

Impact Category


Impact Group

Avb CS CM AT ChT ED

B C C B A B


B C

0.3 0

A

1

ThR

A

Component risk

A

1

EF Value 0.575

ThR

A

Component

Component risk

A

1



Oxygen

Impact Category


Impact Group

Avb CS CM AT ChT ED

C C C B B C


C C

0 0

B

0.3

ThR

C

Component risk

C

0

EF Value 0.075

(Universal, 2015) Outlets: Component

Impact Category

Ethylene Impact Category ABC Impact Group ABC Impact Group Impact Group Rating Rating Numerical Rating

AT ChT ED

B B B

Organisms Organisms Organisms

B

0.3

ThR

A

Component risk

A

1

GWP ODP

B B

Air Air

A

1

AP

A

Air

POCP OD EP OCPP

C C B B

Air Air Water/soil Water/soil

B

0.3

Component

1,2 Dichloroethane

Impact Category

Impact Category ABC Impact Group ABC Impact Group Impact Group Rating Rating Numerical Rating

AT ChT ED

B A B


A

1

ThR

A

Component risk

A

1


C C C B C B B

Air Air Air Air Air Water/soil Water/soil

B

0.3

B

0.3

EF Value 0.65

EF Value 0.65

(Center, 1,2-Dichloroethane, 2014; Ghanta, Fahey, & Subramaniam, 2014; National, Compound Summary for CID 6325 ETHYLENE, 2004; U.S., Health Effects of Ethylene Dichloride (1,2-Dichloroethane), 2002)

OCPP

B

Component

Vinyl Chloride

Impact Category

Water/soil


AT ChT ED

B A B


A

1

ThR

A

Component risk

A

1


B B B C B C B


B

0.3

B

0.3

Component

Hydrogen Chloride

Impact Category


AT ChT ED

A B C


A

1

ThR

C

Component risk

C

0


C C A C C C C


A

1

C

0

Component

Oxygen

Impact Category


AT ChT ED

B B C


B

0.3

ThR

C

Component risk

C

0


C C C C C C C


C

0

C

0

(Dreher, Torkelson, & Beutel, 2012; U.S., Health Effects of Vinyl Chloride, 2000)

EF Value 0.65

EF Value 0.5

EF Value 0.075

Component Impact Category

Water Impact Category ABC Impact Group ABC Impact Group Impact Group Rating Rating Numerical Rating

AT ChT ED

C C C


C

0

ThR

C

Component risk

C

0


C C C C C C C


C

0

C

0

EF Value 0

Biwer Rating Rationale – Direct Chlorination

Direct Chlorination Biwer Impact Rating and Rationale Ethylene 1,2-dichlorethane Inputs Outputs

Chlorine Chlorine Ethylene

Vinyl chloride

Hydrogen chloride

Vinyl Chloride Rating

1,2-dichlorethane Rating

1,2-dichlorethane Rating Rationale

Chlorine Rating Rationale

(Input specifications)

Some critical materials such as...are used and made when creating ethylene (Ghanta et al, 2013) There are no known studies proving that ethylene is highly toxic to humans, but studies have shown ethylene is metabolized into ethylene oxide (a known Ehtylene is relatively toxic to its environment and would not be okay to breath chronically, but does not present high toxicity

Known Carcinogen

Chlorine Rating DCE made from ethylene which is a non renewable resource from fossil fuels

Ethylene Rating Rationale

B

Ethylene Rating Not created with fossil fuels, and no known extinction any time soon (PubChem, CID:24526, 2016) Synthesis of DCE fairly simple, does not require too many steps to produce (Benedict et al)

Impact Category

C

C

B

Synthesis of Chlorine simple, does not require more than a couple steps in a process

B

Avb

C

No Critical Compounds involved (Benedict et al)

CM

B

C

Based on Biwer scoring system and EPA scoring system. (US EPA, 2002 & CDC/NIOSH, 2014)

B

CS

Chlorine easily produced and is present with other molecules in nature, no rare or critical materials used in synthesis

B

AT

B

Ethylene is made from fossil fuels, but resevoirs will not run out within the next 10 years (Ghanta et al, 2013) There are multiple ways to produce ethylene, all of which require over 3 process steps to synthesize (Ghanta et al, 2013)

C

Contact may cause burns and can be fatal if inhaled (US EPA, 2000)

A

ChT

B

B

Vinyl Chloride Rating Rationale

Vinyl Chloride is a kind of VOC which contributes to ozone depletion and global warming but is not a huge cause like florinated hydrocarbons (US EPA, 2002&CameoChemicals, 2016)

A life cycle assessment done on VC showed that the AP=1.5E-2 (Armstrong World Industries, 2014)

Hydrogen chloride Rating

C

A

C

C

C

C

A

B

LC50 for AT listed as 200-2000 mg/m3 on EPA website- which is B CT is listed as extremely high (.00006 mg/m3 reference

B

ED

A

B

B

B

C

No N or P present in compound

C

C

C

C

VC is a VOC which classifies as a carbon polluter, but is not a main contributer to polution, as CO2 is (Cameo Chemicals, 2016)

From same life cycle assessment POCP=1.6E-3 (Armstrong World Industries, 2014) Vinyl chloride is a VOC which is known to have a relatively strong smell (CameoChemicals, 2016)

B

B

EPA has classified VC as a human carcinogen. Case studies suggest correlation of increased birth defects, and decreased fertility rate in women, but studies have not proven causation ( US EPA- Vinyl Chloride, 2002) Flashpoint of Vinyl Chloride is very low, the product is very very flammable (CameoChemicals,

Can cause temporary incapacitation or injury (US EPAVC, 2002)

A

No information present on effect of inhalation or ingestion when dealing with the endocrine system, Also not classifiable as a human carcinogen (PubChem, CID:24526, 2016)

A

B

C

Chlorine is not combustible but increases the reactivity of other substaces it interacts with

B

B

All global warming and ozone depletion data found did not list chlorinated compounds, must assume if they have potential it is negligable compared their florinated counterparts

No information present on the partioning or acidifcation

Scores came from the EPA rating of toxicity (US EPA-VC, 2002)

Highly Flammable, Flashpoint very low (PubChem, 2016)

C

Photochemically degrades to hydroxyl radicals, and is not significantly removed by ozone or Odor Threshold in water is 20 mg/L which is greater than 300 mg/m^3 (CDC/NIOSH, 2014) Is not known to concentrate in soil or aquatic organisms, but chemical spill has proven toxic in water Hazardous Air pollutant in many US states (CDC/NIOSH, 2014)

A

A

C

In water, chlorine is a strong acid (PubChem, CID:24526, 2016)

B

Toxicity range on EPA website designates class A - Probable Carcinogen (US EPA, 2002 & CDC/NIOSH, 2014) No known effect on humans but known to decrease fertitlity in rats and listed as probable carcinogen of humans- There being a possibility of carcinogen, is a good enough reason to list it as a class B (US EPA, 2002) Flash point of DCE very lowpresents a risk in flash evaporating (US Dept HHS, 2001)

ThR

Ehtylene is a hydrocarbon with a GWP less than 20 (Ghanta et al, 2013)

C

B

A

No evidence of chlorine contributing to ozone creation

C

C

C

Chlorine has a suffocating odor (US EPA, 2000)

B

No information present on effect of chlorine on the atmomsphere or its contribution to global warming. It is assumed its contribution is negligable

Is not a major contributor to ozone creation

B

Chlorine toxic in water or soil, however does not contain N or P (US EPA, 2000 & PubChem,

B

In fossil fuel, and compound adds to Ozone depletion, but is not florinated comound Table1 The process that makes ethylene and ethylene itself has a very high potential to acidify the medium it is in, damaging to

Ethylene is fairly odorless (PubChem, 2016)

B

No organic compound present

Although the compound itself does not contain P or N, it is relatively toxic to the environment Ethlyene is an organic compound in petrol oil, and therefore adds to carbon pollution (Ghanta et al, 2013 & PubChem, 2016)

C

C

GWP

C

B

POCP

C

ODP

OD

B

A

EP

B

AP

OCPP

Hydrogen chloride Rating Rationale

Data given in Biwer et al

Biwer Rating Rationale – Oxychlorination

Oxychlorination

Inputs Outputs

Impact Category

Avb

CS

CM

AT

ChT

ED

ThR

GWP

ODP

AP

POCP

OD

EP

OCPP

Biwer Impact Rating and Rationale Ethylene 1,2-dichloroethane

Ethylene Rating

B

B

B

B

B

Hydrogen chloride water

Ethylene Rating Rationale Ethylene is made from fossil fuels, but resevoirs will not run out within the next 10 years (Ghanta et al, 2014) There are multiple ways to produce ethylene, all of which require over 3 process steps to synthesize (Ghanta et al, Some critical materials are used and made when creating ethylene (Ghanta et al, 2014) There are no known studies proving that ethylene is highly toxic to humans, but studies have shown ethylene is metabolized into ethylene oxide (a known carcinogen) (Ghanta et al, 2014) Ehtylene is relatively toxic to its environment and would not be okay to breath chronically, but does not present high toxicity (PubChem, 2016)

Known Carcinogen (Ghanta et al, 2014)

Oxygen Ethylene Vinyl chloride Hydrogen chloride Oxygen

C

Water Rating

C

C

Hydrogen Chloride Rating Rationale

DCE made from ethylene which is a non renewable resource from fossil fuels

A

C

Hydrogen Chloride Rating

Oxygen Rating Rationale

B Synthesis of DCE fairly simple, does not require too many steps to produce

Can cause temporary incapacitation or injury (Cameo Chemicals-VC, 2016)

B

Vinyl Chloride Rating Rationale

Oxygen Rating One of the most abundant chemicals on earth

C

No Critical Compounds involved

B

Scores came from the EPA rating of toxicity

Vinyl Chloride Rating

C

Minimal steps involved in the creation of oxygen

C

Score came from rating on EPA website (US EPA-DCE, 2002)

A

1,2-dichloroethane Rating Rationale

C

No critical materials used in the making of O2

B

Toxicity range on EPA website designates class A - Probable Carcinogen

1,2-dichloroethane Rating

C

When exposed to oxygeen levels >75% can cause lung irritation (UIGI, 2015)

A

C

No information present on the partioning or acidifcation

B

EPA has classified VC as a human carcinogen. Case studies suggest correlation of increased birth defects, and decreased fertility rate in women, but studies have not proven causation

C

C

C

C

B

From Armstrong World Industries

From same life cycle assessment POCP=1.6E-3 (Armstrong World Industries, 2014)

A life cycle assessment done on VC showed that the AP=1.5E-2 (Armstrong World Industries, 2014)

C

C

C

A

C

C

C

C

C

C

C

C

C

C

Flashpoint of Vinyl Chloride is very low, the product is very very flammable (Cameo Chemicals-VC,

B

No N or P present in compound

C

B

C

VC is a VOC which classifies as a carbon polluter, but is not a main contributer to polution, as CO2 is (Cameo Chemicals-VC, 2016)

B

B

Vinyl Chloride is a kind of VOC which contributes to ozone depletion and global warming but is not a huge cause like florinated hydrocarbons (Cameo ChemicalsVC, 2016)

A

C

B

Can cause lung damage, but need to be exposed to high oxygen levels for long periods of time to get damage (UIGI, 2015)

Oxygen is an oxidizer (UIGI, 2015)

B

(Input specifications)

B

C

Negligable if any contribution to ozone creation, O2 reacts to form O3 but does not directly add to

C

Photochemically degrades to hydroxyl radicals, and is not significantly removed by ozone or Odor Threshold in water is 20 mg/L which is greater than 300 mg/m^3 (US Dept HHS, 2001) Is not known to concentrate in soil or aquatic organisms, but chemical spill has proven toxic in water (US Hazardous Air pollutant in many US states (US Dept HHS, 2001)

Scores from Biwer et al

B

Flash point of DCE very lowpresents a risk in flash evaporating (US Dept HHS, 2001)

C

C

Oxygen is a colorless odorless gas

B

All global warming and ozone depletion data found did not list chlorinated compounds, must assume if they have potential it is negligable compared their florinated counterparts

A

No known endocrine effects (UIGI, 2015)

No/ minimal hazard of flammability by MSDS (UIGI, 2015)

C

C

B

Highly Flammable, Flashpoint very low (PubChem, 2016)

No known effect on humans but known to decrease fertitlity in rats and listed as probable carcinogen of humans- There being a possibility of carcinogen, is a good enough reason to list it as a class B

A

C

C

Non-toxic and compound does not contain N or P

B

O2 has negligable effects on global warming and ozone depletion, no data on global warming and oxygen

C

Not an organic compound

C

C

C

Ehtylene is a hydrocarbon with a GWP less than 20 (Ghanta et al, 2014)

Although the compound itself does not contain P or N, it is relatively toxic to the Ethlyene is an organic compound in petrol oil, and therefore adds to carbon pollution (PubChem 2016)

Ethylene is fairly odorless (Ghanta et al, 2014)

In fossil fuel, and compound adds to Ozone depletion, but is not florinated comound The process that makes ethylene and ethylene itself has a very high potential to acidify the medium it is in, damaging to biological factors There is no solid evidence to suppoort ethylene having a POCP value

B

B

A

C

C

B

B

Water Rating Rationale

Scores came from Biwer et al

Appendix D: Financial Sustainability

Figure D.1 – Bare model factors of Guthrie (1974). From (Seider, Seader, Lewin, & Widagdo, 2009).

Estimate of Total Capital Investment An assessment of the Capital Investment was made to determine the expenses occurring within the primary year of production. From the calculated purchase costs, the total bare-module investment can be prepared to use in capital estimation. The bare-module factors for each type of equipment can be found in Bare-Module Costing. Bare-module costs, CBM, for each piece of equipment can be calculated by the following equation: 𝐶𝐵𝑀 = 𝐹𝐵𝑀 𝐶𝑃 Using the total bare-module cost, an estimate of the total capital investment from (Seider, 2009) is produced. Various costs were summed to achieve the final capital investment (US, 2002). Capital costs for spare items of equipment, Cspare, were taken as the replacement cost of process machinery such as pumps. Costs for storage tanks, Cstorage, were modeled after the rate of production. Cone roof storage tanks were used after obtaining the volume of raw material or product needed per week. It was assumed that at least 7 days of materials would be needed for storage.

𝑀𝑎𝑠𝑠 𝐹𝑙𝑜𝑤 𝑅𝑎𝑡𝑒 𝑜𝑓 𝑅𝑎𝑤 𝑀𝑎𝑡𝑒𝑟𝑖𝑎𝑙 𝑜𝑟 𝑃𝑟𝑜𝑑𝑢𝑐𝑡 ∗ 7 𝑑𝑎𝑦𝑠 ∗ 24 ℎ𝑜𝑢𝑟𝑠 ∗

𝐶𝑜𝑛𝑒 𝑅𝑜𝑜𝑓: 𝐶𝑃 = 265𝑉 0.51

1 𝑤𝑒𝑒𝑘 𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑚𝑎𝑡𝑒𝑟𝑖𝑎𝑙 = 7 𝑑𝑎𝑦𝑠 𝑤𝑒𝑒𝑘

𝐶𝐸2016 𝐶𝐸2006

The previous costs can be summed to obtain the true total bare-module investment. Other investment costs such as site preparation, Csite, were taken to be in the range of 4-6% as recommended by (Seider, 2009) for an addition to an existing integrated complex. Service facilities and Allocated costs were omitted from capital investment calculations as it was specified that the existing utilities can support new processing units and the warehouse on site will have enough space. The sum of these costs yields the direct permanent investment, CDPI. Once a recommended contingency fee of 18% is applied to this sum, the total depreciable capital, C TDC, is obtained. No royalties or licensing fees were incurred, but a cost of startup was associated with the plant. As a moderate chemical process, an estimate of 10% of the CTDC was taken as the startup cost, Cstartup. Working capital funds can be determined with factors found in the operating “cost sheet” that estimates the total cost of production. The total sum of these factors can be described as the total capital investment, CTCI. A summary of the costs can be found in the financial sustainability section of the report. Sample storage tank calculation: Cone roof Chlorine Ethylene VC HCl Total

Flows 117072.9 139550.8 94459.85 112596.1 135427.8 161429.9 70929.12 84547.51 417889.6 498124.4 0.41789 indexed 0.498124

g/wk g/wk g/wk g/wk g/wk g/wk

999.08 655.9 1329.3 374

gal/hr gal/hr gal/hr gal/hr

153704.6154 100907.6923 204507.6923 57538.46154

gal/wk

HCl Ethylene VC O2

3781.96 2482.88 5113.06 1416

DC process kg/hr kg/hr kg/hr kg/hr

Estimate of Total Production Costs The continuing costs associated with the operation of a plant can be described by a cost sheet of representative unit cost factors (Donati, 1997). When summed, these factors yield the total cost of production, C TPC. A major consideration in these unit factors are the feedstock and utilities costs. To determine the feedstock and utility costs, the operating factor for the plant was specified as 8000 hours per year, and indexed costs of raw materials and utilities were found in (Seider, 2009). The following equations were then used. Cost factors for the resulting costs are outlined within the cost sheet as recommended by (Seider, 2009). No general expenses were associated with the total production cost. 𝑀𝑎𝑠𝑠 𝐹𝑙𝑜𝑤 𝑅𝑎𝑡𝑒 𝑜𝑓 𝑅𝑎𝑤 𝑀𝑎𝑡𝑒𝑟𝑖𝑎𝑙

𝑘𝑔 ℎ𝑟 $ $ ∗ 8000 ∗ 𝐶𝑜𝑠𝑡 𝑜𝑓 𝑅𝑎𝑤 𝑀𝑎𝑡𝑒𝑟𝑖𝑎𝑙 = 𝐹𝑒𝑒𝑑𝑠𝑡𝑜𝑐𝑘 𝐶𝑜𝑠𝑡 ℎ𝑟 𝑦𝑟 𝑘𝑔 𝑦𝑟

𝑅𝑎𝑡𝑒 𝑜𝑓 𝑈𝑡𝑖𝑙𝑖𝑡𝑦 (𝐹𝑟𝑜𝑚 𝐴𝑠𝑝𝑒𝑛 𝑃𝑙𝑢𝑠)

𝑈𝑛𝑖𝑡 ℎ𝑟 $ $ ∗ 8000 ∗ 𝐶𝑜𝑠𝑡 𝑜𝑓 𝑈𝑡𝑖𝑙𝑖𝑡𝑦 = 𝑈𝑡𝑖𝑙𝑖𝑡𝑦 𝐶𝑜𝑠𝑡 ℎ𝑟 𝑦𝑟 𝑈𝑛𝑖𝑡 𝑦𝑟

Upon completion of the cost sheet for total production cost, the working capital for each plant can be determined. The working capital is then added to the total capital investment to reflect a more accurate estimation. The following equation defines working capital. 𝐶𝑊𝐶 = 𝑐𝑎𝑠ℎ 𝑟𝑒𝑠𝑒𝑟𝑣𝑒𝑠 + 𝑖𝑛𝑣𝑒𝑛𝑡𝑜𝑟𝑦 + 𝑎𝑐𝑐𝑜𝑢𝑛𝑡𝑠 𝑟𝑒𝑐𝑖𝑒𝑣𝑎𝑏𝑙𝑒 − 𝑎𝑐𝑐𝑜𝑢𝑛𝑡𝑠 𝑝𝑎𝑦𝑎𝑏𝑙𝑒 For the basis of this calculation, the following parameters were assumed from (Sieder, 2009). 1. 2. 3. 4.

Cash reserves accounted for 8.33% of the annual cost of manufacture. Inventory amounted to 1.92% of annual sales of liquid and solid products Accounts receivable amounted to 8.33% of all annual sales. Accounts payable amounted to 8.33% of annual feedstock costs.

Profitability ROI and PBP: The return on investment (ROI) of a process plant can be defined as a percentage return per year. The total capital investment divided the annual earnings yields the annual interest rate made by the profits on the original investment (Guthrie, 1974). For simplicity, the depreciation in ROI is computed using straight-line depreciation for 10 years. Also, the plant is assumed to operate each year, including the first, at 90% capacity with a 40% income tax rate. Using these guidelines, the ROI can be computed using the following equations. S is defined as the total sales revenue, C is the annual production cost, and D is the annual depreciation. 𝑅𝑂𝐼 =

𝑛𝑒𝑡 𝑒𝑎𝑟𝑛𝑖𝑛𝑔𝑠 (1 − 𝑡)(𝑆 − 𝐶) = 𝑇𝑜𝑡𝑎𝑙 𝐶𝑎𝑝𝑖𝑡𝑎𝑙 𝐼𝑛𝑣𝑒𝑠𝑡𝑚𝑒𝑛𝑡 𝐶𝑇𝐶𝐼

𝐶𝑇𝐶𝐼 = 𝐶𝑇𝐷𝐶 + 𝐶𝑊𝐶 The payback period (PBP) is the time required for the annual earnings to equal the original investment. Using the same guidelines applied to the ROI, the PBP can be calculated. Due to rapid progress of technology, a PBP 𝐶

𝑇𝐷𝐶 of more than 4 years will indicate that the project is not recommended. 𝑃𝐵𝑃 = (1−𝑡)(𝑆−𝐶)+𝐷

Sample calculation of ROI and PBP (PP):

ROI TPC w/ depreciation Pre-tax earnings Income taxes After-tax earnings TCI (TDC + WC) ROI eqn 23.7 PP eqn 23.8

39.37611 0.61904 0.247616 0.371424 10.09153 4%

6.04 yrs

NPV and IRR: Net present value (NPV) is the sums of discounted cash flows over a plant’s lifespan. These cash flows are compared against a set interest rate. The interest rate for this plant’s company is specified at 15%. For the first 3 years, including permitting, a third of the capital investment was used each year. For NPV purposes, the first year of production occurred at 30% capacity, the second year at 60%, and the 3 and subsequent years at 90%. The plant’s production life-span is approximately 15 years. After the 15th year, the working capital is recovered and the plant is sold for salvage. To compute the cash flows, a 10-year straight-line depreciation was considered. A chart of cash flows is presented in the Profitability assessment of the report. The calculations of cash flows are presented in the following equations. 𝑁𝑒𝑡 𝐸𝑎𝑟𝑛𝑖𝑛𝑔𝑠 = (𝑆 − 𝐶𝐸𝑥𝑐𝑙.

𝐷𝑒𝑝.

− 𝐷) ∗ (1 − 𝑖𝑛𝑐𝑜𝑚𝑒 𝑡𝑎𝑥 𝑟𝑎𝑡𝑒)

𝐷𝑖𝑠𝑐𝑜𝑢𝑛𝑡𝑒𝑑 𝐶𝑎𝑠ℎ 𝐹𝑙𝑜𝑤 = 𝑁𝑒𝑡 𝐸𝑎𝑟𝑛𝑖𝑛𝑔𝑠 + 𝐷 𝐴𝑛𝑛𝑢𝑎𝑙 𝐶𝑎𝑠ℎ 𝐹𝑙𝑜𝑤 = 𝐶 = (𝑁𝑒𝑡 𝐸𝑎𝑟𝑛𝑖𝑛𝑔𝑠 + 𝐷) − 𝑓𝐶𝑇𝐷𝐶 − 𝐶𝑊𝐶 The annual cash flows can then be summed to obtain the cumulative present value of discounted cash flows. The internal rate of return is defined as the point at which the NPV is zero. This is done by adjusting the tax interest rate until the investment in repaid at the end of the project. The IRR was calculated with the same methods as the NPV, but iteratively solving for the point at which the cumulative present value was zero. Excel solver was used to compute this value. Sample Calculation of IRR:

Using the above Solver method, we were able to examine the sensitivity of %IRR to changes in TCI, capacity, and price of vinyl chloride (Ogle, 2014).

Sensitivity of IRR

The graph shows sensitivity of the internal rate of return to the price of vinyl chloride, capacity, and TCI. While TCI maintains a linear relationship the IRR appears to vary logarithmically with both the capacity and price of vinyl chloride. No IRR was possible at relative price of VC below 79%, or a plant capacity below 71%. Below those thresholds, there was no interest rate that would allow the plant to break even in 15 years of production.

%TCI 50% 75% 100%

%IRR 46% 40% 36%

125% 150%

33% 30%

% Capacity 71% 75% 90%

%IRR 2% 13% 36%

% Price of VC 79% 94% 100% 125% 150%

%IRR 2% 30% 36% 54% 67%

Cost Sheet for Direct Chlorination Model

Cost Item Feedstocks (raw materials) Chlorine Ethylene Total Feedstocks Utilities Steam, 150 psig Electricity Refrigerant Total Utilities

Operations (O) Direct wages and benefits (DW & B) Direct salaries and benefits Operating supplies and services Technical assistance to manufacturing Control laboratory Total Operations (O) Maitenance (M) Wages and benefits (MW & B) Salaries and benefits Materials and services Maintenance overhead Total Maintenance Total of M&O - SW&B Operation overhead General plant overhead Mechanical department services Employee relations department Business services Total operating overhead Property taxes and insurance Depreciation Direct plant Allocated plant Total depreciation Total Cost of Manufacture (COM) General Expenses Total Product Cost (TPC)

Cost Factor

Unit Cost ($/metric ton of VC)

Comment

0.32 0.03 0.12 0.47

7.47 * 0.78 * 2.90 * 11.15 Modeled as moderatecapacity continuous fluids process 30 shift operators w/ 5 25.85 shifts/day 3.88 1.55 7.10 7.69 46.07

Annual Cost (MM$/yr)

$12.57/Metric Ton $0.06/kW-hr $12.21/GJ

1.09 0.16 0.07 0.30 0.33 1.95

*Indexed cost as MS Index = 596 for 2016 (Seader, 2016) 438.25 * 401.54 *

$35/operator-hr 15% of DW&B 6% of DW&B $60,000/(operator/shift)-yr $65,000/(operator/shift)-yr

4.70 1.17 4.70 0.23 10.80 35.59

18.52 16.96

3.5% of TDC 25% of MW&B 100% of MW&B 5% of MW&B

0.20 0.05 0.20 0.01 0.46 1.50

$0.38/kg $0.88/kg

7.1% of M&O-SW&B 2.4% of M&O-SW&B 5.9% of M&O-SW&B 7.4% of M&O-SW&B

2.53 0.85 2.10 2.63 8.12 2.68

10-year SL depreciation

0.11 0.04 0.09 0.11 0.34 0.11

13.41 0.00 13.41

2% of TDC

0.57 0.00 0.57 10% of TDC 6% of Calloc

39.38

Cost Sheet for Oxychlorination Model

Cost Factor

2.72 17.48 0.68 20.88

Comment

$0.09/kg $0.88/kg $0.06/kg

0.32 0.04 0.01 0.10 0.47

7.84 * 0.93 * 0.26 * 2.51 * 11.54 Modeled as moderate-capacity continuous fluids process 30 shift operators w/ 5 26.70 shifts/day 4.00 1.60 7.33 7.95 47.58

Unit Cost ($/metric ton of VC)

Cost Item

$12.57/Metric Ton $0.06/kW-hr $0.019/m^3 $12.21/GJ

1.09 0.16 0.07 0.30 0.33 1.95

Annual Cost (MM$/yr)

Feedstocks (raw materials) HCl Ethylene Oxygen Total Feedstocks

$35/operator-hr 15% of DW&B 6% of DW&B $60,000/(operator/shift)-yr $65,000/(operator/shift)-yr

4.02 1.00 4.02 0.20 9.24 35.72

10-year SL depreciation

*Indexed cost as MS Index = 596 for 2016 (Seader, 2016) 66.570 * 427.324 * 16.616 * 510.51

Utilities Steam, 150 psig Electricity Cooling Water (cw) Refrigerant Total Utilities

3.5% of TDC 25% of MW&B 100% of MW&B 5% of MW&B

0.16 0.04 0.16 0.01 0.38 1.46

2.54 0.86 2.11 2.64 8.14 2.29

Operations (O)

7.1% of M&O-SW&B 2.4% of M&O-SW&B 5.9% of M&O-SW&B 7.4% of M&O-SW&B

0.10 0.04 0.09 0.11 0.33 0.09 2% of TDC

11.47 0.00 11.47 10% TDC 6% of Calloc

24.57

0.47 0.00 0.47 24.57

Direct wages and benefits (DW & B) Direct salaries and benefits Operating supplies and services Technical assistance to manufacturing Control laboratory Total Operations (O) Maitenance (M) Wages and benefits (MW & B) Salaries and benefits Materials and services Maintenance overhead Total Maintenance Total of M&O - SW&B Operation overhead General plant overhead Mechanical department services Employee relations department Business services Total operating overhead Property taxes and insurance Depreciation Direct plant Allocated plant Total depreciation Total Cost of Manufacture (COM) General Expenses Total Product Cost (TPC)