Polyester Resin Manufacture

Final Report – Design of

Polyester Resin Plant –

Chem Eng 4W04

Submitted to: Dr. M. Saban

Team Magenta

B. Pambianco

A. Ladd

G. Voloshenko

N. Kirupa

S. Neheli

S.Wani

4/6/2011

2

McMaster University

6 April, 2011

1280 Main Street West

Hamilton, ON

L8S 4L9

To: Dr. M. Saban

From: Team Magenta (B. Pambianco, A. Ladd, G. Voloshenko, N. Kirupa, S. Neheli, S. Wani)

Subject:

Design of Polyester Resin Pant

Dear Dr. M. Saban,

As requested in the Chemical Plant Design and Simulation class, please find attached the

final version of the polyester resin plant report. The report studies the production of polyester

resin from dimethyl terephthalate (DMT), and includes an overview of plant setup and

operation, as well as process safety and economics.

Resin production from DMT requires a two-step process. DMT and glycols are first

charged into a 2500 gallon reactor. Transesterification and polycondensation reactions are

then undertaken in high temperature and vacuum conditions. The final product is poly

(1,2-propylene-diethylene-terephthalate) resin with a Mn of 6000

_molg

and an average DP of 95%.

Two 2500 gallon reactors operate in parallel on a 24 hour cycle, offset by 12 hours to allow for

shared use of processing facilities. Plant capacity is 3000 tonnes of resin per year, operating 42

weeks of the year. The plant is located in Sarnia, Ontario.

Alternatives available to the process described in this report are summarized below.

Within this Report

Alternative

Process Used

Ester Route

Acid Route

Number of Reactors

Two, Parallel Configuration

One

Processing Equipment

Cooling Belt

Rotoform

Current market price for the resin is $5 per kilogram. Based on this value, cost analyses

were conducted for both this process and a popular alternative, the acid route.

(cost / kg resin)

Ester Route

Acid Route

Raw Material

$2.75

$1.92

Manufacturing

$0.65

$0.82

Profit

$1.60

$2.26

Capital Investment

$11,000,000

$10,000,000

NPV (12 years)

$25,400,000

$40,700,000

Based on the conclusions reached within this report, it is recommended that further

development of this project be approved.

Sincerely,

B. Pambianco

Team Magenta

3

Contents

1.0 Introduction ... 5

2.0 Process Description ... 6

3.0 Work Schedule ... 9

4.0 Process Mass and Energy Balance ... 10

5.0 Process Control ... 12

5.1 Preliminary P&ID diagram ... 12

5.2 End point control strategy description ... 13

5.3 Vacuum application control strategy ... 14

5.4 Control of major pieces of equipment ... 14

6.0 Reactor Design and Sizing ... 15

6.1 Reactor Design ... 15

6.2 Ports ... 16

6.3 Agitator System ... 17

7.0 Other Equipment Design and Sizing... 18

7.1 Condensers... 18

7.1.1 Take-Off Condenser ... 18

7.1.2 Methanol Condensor ... 18

7.2 Packed Tower ... 19

7.3 Vessels ... 21

7.3.1 Raw Material Storage ... 21

7.3.2 Receivers ... 23

7.3.3 Methanol Storage and Glycol Recycle ... 24

7.3.4 Product Storage Silos ... 25

7.4 Downstream Equipment ... 26

7.4.1Cooling belt system ... 26

7.4.2 Disintegration equipment ... 27

7.5 Utility Equipment ... 28

7.5.1 Hot Oil Utility... 28

7.5.2 Cooling Tower Utility... 30

7.6 Pumps ... 32

4

8.1 Hazardous Conditions ... 33

8.2.1 Plant Classification (electrical safety) ... 33

8.2.2 Operational Safety ... 33

8.2.3 Thermal Process Safety ... 35

8.3 Waste Disposal ... 35

9.0 Floor Plan ... 36

10.0 Economic Analysis ... 37

10.1 Capital Costs, Installation Costs and Expense/Fees ... 37

10.2 Operating Costs ... 40

10.3 Income statement over 12 years accounting period ... 41

10.3.1 Sensitivity Analysis on the selling price... 43

10.3.2 Sensitivity Analysis on the raw feed prices ... 44

10.4 Acid Route Alternative Analysis ... 44

11.0 Conclusions/Recommendations ... 46

12.0 Acknowledgments ... 47

5

1.0 Introduction

The assigned project for Team Magenta was to design a safe, simple, robust and economical plant for production of a specialty polyester resin. The team made some initial decisions about the overall plant design, such as the use of two reactors, and proceeded to design the plant for an annual

production capacity of 3000 tonnes. Team members were delegated responsibility for specific parts of the design. Brandon was responsible for reactor design, impeller/agitator design, economic analysis and cooling tower design; Greg was responsible for the initial process description and production schedule, pump sizing and costing, and the acid route alternative; Shariq was responsible for the downstream equipment sizing and selection, process chemistry, and overall editing; Scott was responsible for the process energy balances, reactor kinetics and profiles, utilities, and operating costs; Alex was

responsible for the PFD, P&ID, floor plan and packed column design; Nijastan was responsible for raw material and product tanks, selection of the hot oil column; condenser design, and process safety.

A plant location was selected in Sarnia as the area has housed large industrial plants for decades, is considered to be an international leader in chemical production, and has access to

continental railways. A marketing study was conducted and determined that the industry has an annual demand of 160,000 tonnes/year (in US alone) with an average market price of 5-7 $/kg.

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2.0 Process Description

The transesterification (TE) reaction, which involves the substitution of an organic group from an ester with an organic group from an alcohol, is conducted between 160°C and 210°C at atmospheric pressure for approximately 5 hours. The pre-polymer formed from the TE reaction is used in the

polycondensation (PC) reaction to produce the polyester resin by applying a vacuum over about a 6 hour period for a temperature ranging between 200°C and 220°C. The final product will be discharged onto a classic cooling belt as a film in a molten state before passing through a flaker and hammer-mill

pulverizer to allow for easy storage in silos.

Figure 1: The temperature profile for the reactor in the process.

Figure 2: The pressure profile for the reactor in the process

The ester route chemistry involves reacting dimethyl terephthalate (DMT), diethylene glycol (DEG), and 1,2-propylene glycol (PG) to form the prepolymer, while evolving the byproduct methanol.

DMT + 2(DEG + PG) ↔ BHDT/PT + 2MeOH ↑ (1) Monomer ↔ poly (1, 2-propylene-diethylene-terephtahalate) + glycol ↑ (2)

0 50 100 150 200 250 0 2 4 6 8 10 12 14 R e ac to r Tem p e ratu re (C) Time (h) 0 100 200 300 400 500 600 700 800 0 2 4 6 8 10 12 14 R e ac to r Pr e ssur e ( m m H g) Time (h)

7

The direct esterification (DE) process, or acid route, is the alternative to the transesterification process. The acid route chemistry involves the reaction of purified terephthalic acid with ethylene glycol to form the prepolymer, while evolving the byproduct water.

PTA + 2EG ↔ BHET + 2H2O ↑ (3)

Monomer ↔ poly(ethylene terephthalate) (4)

The DE process is capable of generating a resin with a higher average degree of polymerization in a shorter period of time than the TE process [1]. A short comparison between the two processes is made in the table below.

Table 1: Comparison of Direct Esterification and Ester-Interchange Routes

The plant scale-up and equipment selection was based on a required production of 3,000 tons/year of polyester resin. A classic cooling belt and two reactor system arrangements were chosen. The ester route chemistry is used since data was previously made available from the pilot plant. The reactor design parameters were based on an end-point viscosity of approximately 5.3 Pa-s which was determined using MFI pilot plant data and adjusting for the temperature requirements. Table 2 summarizes advantages and disadvantages of this plant configuration.

Table 2: Summary of Configuration Costs and Benefits for a Two Reactor Plant

Advantages Disadvantages

Redundancy High initial capital cost due to additional

equipment needed for redundancy Maximize use of downstream equipment

Two products can be made in the same plant

Specification Direct Esterification Process Transesterification Process

Process type Batch Batch

Feed Purified terephthalic acid, ethylene glycol

DEG, PG, DMT

Catalyst required? Yes Yes

Reactor configuration Two stirred reactors in series, followed by multi-stage polymerizer

Single stirred reactor Process description Catalyzed esterification in primary

reactor to 90% conversion, then esterification in second reactor to 98%

conversion, then heated and pressurized in polymerizer

Transesterification of DMT with glycols to form intermediate oligomers, followed by catalyzed

polycondensation

Reaction time 9 hours 11 hours

Reaction conditions 245 - 275 oC; 0.133 - 275 kPa 215 oC, 0.133 kPa

Vacuum required? Yes Yes

Byproducts Water Methanol

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The catalyst chosen, Fascat 4100, is compatible with both the TE and PC reactions while minimizing potential side reactions. It does not require any special handling or filtration once the reactions are complete. A single 50kg bag is added per reactor charge.

Table 3: Information for Start-up Batch Charges (A) and Normal Batch Charges (B) per Reactor

Stream Stream Information Batch Charges A (Kg) Batch Charges B (Kg)

1 DMT 5156 5156

2 PG 3536 2263

3 DEG 704 386

4 Product 5669 5669

Table 4: Physical properties of all materials in the plant

Material Properties

Dimethyl Terephthalate (DMT) Diethylene Glycol (DEG)

Chemical formula

C

10

H

10

O

4

C

4

H

10

O

3

Flash Point (

o

C)

153

138

Form

Solid/Molten Liquid

Liquid (clear viscous)

Melting Point (

o

C)

140

-8

Molecular Weight (g/mol)

194.19

106.12

Vapour Pressure (mm Hg)

1.2 at 20

o

C (solid)

1.12

Colour

White

Colourless. Clear

Odour

Slight to none

Odorless

Density (g/cm

3

)

1.35

1.036

Toxology (acute effects mg/kg)

3200

12565

Propylene Glycol (PG)

Methanol (MeOH)

Chemical formula

C

3

H

8

O

2

CH

3

OH

Flash Point (

o

C)

99

11

Form

Liquid (oily liquid)

Liquid

Melting Point (

o

C)

-59

-98

Molecular Weight (g/mol)

76.1

32.04

Vapour Pressure (mm Hg)

1.035

97.7

Colour

Colourless. Clear

Colourless. Clear

Odour

Odorless

Mild alcohol odour

Density (g/cm

3

)

1.118

0.7918

Toxology (acute effects mg/kg)

20000

5628

The cycle time for each reactor is summarized in Table 5. As all downstream equipment is shared between the two reactors, the cycles are staggered by 10 hours to allow sufficient processing time for each batch. Having two staggered cycles also provides increased process flexibility as it is possible to continue operation of one cycle while the other is down.

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Table 5: Operating Schedule

Task Time for Reactor A (hours) Time for Reactor B (hours)

Start time Duration Start time Duration

Raws charging 0600 3 2100 3 Heating up 0900 1 0000 1 Transesterification stage 1000 5 0100 5 Polycondensation stage 1500 6 0600 6 Discharging 2100 3.5 1200 3.5 Resin cooling 2100 3.5 1200 3.5 Resin crushing 2130 3.5 1230 3.5 Resin grinding 2130 3.5 1230 3.5 Batch Complete 0100 1600

Total cycle time: 20 hours 20 hours

The recycled glycols have an 80:20 PG to DEG ratio once condensed from the PC stage. Under normal operating conditions the recycled glycols will be blended with new glycols to match batch specifications. Periodically some of the recycled glycols will be purged from the system to minimize impurities. After being separated and collected the methanol is then sold on the market for $350/ton.

3.0 Work Schedule

The plant will be in operation for 42 of the 52 weeks per year. This will allow for 2 weeks of scheduled holiday for Christmas and New Year’s time, along with 2-scheduled shut downs, each

consisting of 3 weeks, and a remaining 2 weeks for unscheduled shutdown. These scheduled shutdowns will allow for maintenance, repairs, and upgrades which can be made to ensure reliable performance of the equipment during plant operating.

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4.0 Process Mass and Energy Balance

Table 6: Process Mass and Energy Balance Summary

Process Flow In (kg/batch)

Process Flow Out (kg/batch)

Peak Utility Flow

(m^3/h) Utility Type Power Required (kW) Unit 1: Upstream Tanks: TK 101 A/B 386.39 TK 102 A/B 2263.39

TK 103 A/B 5155.66 0.180 (both tanks) Oil 11.185 (both tanks)

Unit 2: Processing

Reactor: R 201 A/B Raws Feed 7805.44 21.82 Oil 15.4

R 201 A/B Glycols 1590.14 2014

R 201 A/B Methanol 1674

R 201 A/B Product 5668.88

Exchanger: E 201 A/B 1674 1674 3.46 Water

E 202 A/B 2014 2014 9.29 Water

Column: T 201 A/B Total Feed 16740

T 201 A/B Methanol 1674

T 201 A/B Glycols 15066

Tanks: V 201 A/B 1674 1674

V 202 A/B Total Feed 2014 0.6987 Water

V 202 A/B To Storage 1913 V 202 A/B To V-203 A/B 101 V-203 A/B 101 101 0.0369 Water V-204 2014 TK 201 1674

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Unit 3: Downstream

Equipment: CB 301 5668.88 5668.88 4.067 Chilled Water 155.83

HM 301 5668.88 5668.88 29.83 CB 302 CB 303 Silos: TK 301 A/B 5668.88 TK 302 Unit 4: Utilities Equipment: F 401 22 Oil 13.4 CT 401 13.48 Water 3.19 Pumps

Capacity (m^3/h) Material Pumped

*duty for both pumps where applicable* Unit 1: P 101 37.855 DEG 19 P 102 A/B 3.43 DEG 4 P 103 34.01 PG 19 P 104 A/B 0.629 PG 4 P 105 37.855 DMT 19 P106 A/B 4.29 DMT 4

Unit 2: P 201A/B 1.13 Methanol 4

P 202 A/B 4 Air (For Vacuum) 44

P 203 A/B 1.8 Glycols 4

P 204 1.71 Glycols 2

Unit 4: P 401 A/B 22 Water 60

P 402 A/B 20.2 Oil 60 Misc. Lighting and Instrumentation 13.75

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5.0 Process Control

5.1 Preliminary P&ID diagram

T-201A E-201A E-202A V-201A V-202A V-203A P-202A TK-102A CB-301 TK-102B HM-301 TK-301A 202A T-201B E-201B E-202B V-201B V-202B V-203B P-202B 202B V-204 E-203B E-203A P-101 P-103 P-105 P-102A P-104B P-102B P-104A P-106A P-106B P-203A P-204 R-201A R-201B CT-401 F-401 TK-301B TK-302 P-201A P-201B P-401A P-401B P-402A P-402B 202B 202B 201A 201B 201B 201A 401 P-203B TRC PRC FRC TRC PRC TRC FRC TRC LRC 1A 1B 2A 2B 3A 3B 4A 4B 5A 5B 6A 6B 7A 7B 8A 8B 9A 9B 10B 10A 11A 12A 11B 12B 13 14 16 17 WATER SUPPLY C-201 TK-201 TK-101A TK-101B TK-103A TK-103B 15B 15A CB-302 Figure 3: P&ID

13

Section 4 includes a detailed list of each piece of equipment labeled on the P&ID including some key equipment properties. The red and yellow lines on the P&ID are the outlet and inlet flows for the hot oil unit, respectively, while the dark and light blue lines are the outlet and inlet streams for the cooling tower, respectively. Table 5 below corresponds to the stream labeling on the P&ID for both start up conditions and normal operating conditions.

Table 7: P&ID Mass Charging and Process Requirements

Stream Description

Start-up Material Requirements (kg)

Normal Operation Material Requirements (kg)

1 A/B DEG 704 322

2 A/B PG 3536 2005

3 A/B DMT 5156 5156

4 A/B Reactor Product 5669 5669

5 A/B Packed Column Feed 16738 16738

6 A/B Packed Column MeOH 1674 1674

7 A/B Packed Column MeOH Reflux ---- ----

8 A/B Packed Column PG 15064 15064

9 A/B Take-off Condensor Glycol 2014 2014

10 A/B Glycol Receiver Feed 101 101

11 A/B Glycol Receiver 1 Outlet 1913 1913

12 A/B Glycol Receiver 2 Outlet 101 101

13 Glycol Purge ---- ----

14 Glycol Recycle to Reactor 0 1913

15 A/B Methanol Byproduct 1674 1674

16 Crusher Feed 5668 5668

17 Storage Feed 5668 5668

5.2 End point control strategy description

The exponential increase of the molecular weight over the extent of reaction makes it challenging to ensure a correct and consistent viscosity is achieved. The window is a narrow one such that if it is gone above, equipment damage is possible; and if too low, the polymer will not have the required properties needed. Hence for this reason, a proven inline viscosity measuring device is used along with the temperature and pressure sensors to accurately determine when to stop the reactor. The proposed device is a Dynatrol Viscosity Probe that utilizes a vibrating rod immersed in the reactor. [2]

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Figure 4: Dynatrol® Viscosity Measurement Probe [2]

It is made of stainless steel and can operate under pressure as well as vacuum, and can be made to operate at high temperatures. The advantage to this device is that there are no moving parts and it is extremely wear resistant. This will allow the process to run uninterrupted without having to break the vacuum to test the product quality. It will be placed on the side of the reactor approximately 25% of the height from the bottom. This placement is important to ensure that it is not in a dead spot and to ensure that it is low enough that polymer will be present at this spot always, as the reactor will never be less than 25% full.

5.3 Vacuum application control strategy

To control the vacuum application during the transesterfication stage, a control system using a pressure gauge in the reactor will be used. The controller will mimic the pressure profile required to remove the glycols over time by operating a valve preceding the take-off condenser. A two valve system, a main and trim valve, or a single valve which includes a trim feature can be used to improve the

precision of the applied vacuum and stabilize any large abnormalities. Choke valves, more specifically butterfly valves, are a common valve used in pressure controlled systems since they always induce a pressure drop in the system. They also have built in fail open and close features to prevent safety issues and potential damage to equipment.

5.4 Control of major pieces of equipment

It is important to ensure that the employees know everything that is happening in the major pieces of the system in the most efficient way possible. This will ensure that if something does go wrong that it can be rectified quickly with minimal damage economically and physically. Each major

component of the system has a variety of sensors and control systems in place. The reactor has

temperature sensors that regulate the hot oil entering the heating jacket to ensure the system is under a constant and specific temperature. The function of the pressure sensor and controller is to ensure the right amount of vacuum is used for the second part of the reaction. The level sensor can be used for safety reasons as well as another indicator of when the reaction is completed. The distillation column has temperature sensors on the top and bottom trays to create a temperature gradient which will use to control the reflux ratio. The Cooling belt has temperature sensors that regulate the flow rate of water and to ensure constant cooling of polymer.

15

6.0 Reactor Design and Sizing

6.1 Reactor Design

Table 8: Reactor Design Specifications

Volume [m3] 10

Internal Diameter [m] 2.2

Height [m] 2.8

Number of Ports 8

Number of Instrument Ports 4

Material Of Construction NiCrMo stainless steel

Jacketed Yes

Vacuum rated Yes, up to 4mmHg

Light/Camera equipped Yes, for remote viewing capabilities.

16 Glycols from Column (2 inches) Glycols to Column (2 inches) Nitrogen (1 inch) DEG Loading (3 inches) PG Loading (5.5 inches) DMT Loading (6 inches) Manhole (20 inches) Agitator Inlet (5 inches)

Figure 6: Reactor Overhead (to scale)

6.2 Ports

On top of reactor:

1. PG loading 5.5”

2. DEG loading 3”

3. DMT (molten) loading 6”

4. Agitator shaft inlet 5”

5. Manhole – 20” ID equipped with a sightglass, also used for solid catalyst loading

6. MeOH/Glycol outlet 2”

7. Glycol from column 2”

8. Nitrogen port 3”

Sensor Probes needed:

1. Temperature sensor

2. Pressure sensor

3. Viscosity sensor (see section 5b)

4. Level sensor

17 Discharge:

One heat traced discharge line at the bottom of the reactor is used for discharging of finished product to the single cooling belt. This will be a segment ball valve to reduce maintenance due to larger bore diameter and containing a polished inner surface. The cutting and cleaning action of the ball and seat eliminate wear and valve blockage due to the high viscosity polymer.

The outlet valve on each reactor will be connected by a heat traced line to a common pipe to travel to the single cooling belt. All lines travelling to the cooling belt containing the polymer resin are heat traced and lengths will be minimized to ensure ease of travel. The line will also have the capability of being purged so that no product will be trapped in the line to avoid possible blockage.

6.3 Agitator System

Table 9: Agitator System Specifications

Agitator Power [kW] *see memo #1 15.4

Agitator speed [RPM] 24 and 42 (dual setting)

Number of Impellers 3

Blade Type P4/45

Number of Baffles 4

Baffle Width [m] 0.122

Baffle Clearance [m] 0.025

Agitator Height [m] Located at 0.7, 1.4, 2.1 meter from the bottom

Agitator Diameter [m] 1

Agitator Shaft Diameter 5”



Three P4/45 turbine blades will be used and placed at 0.25H, 0.5H, and 0.75H of the

tank. This will allow proper mixing during the beginning of the reaction when the

reactor is at its fullest. As the volume decreases the top blade will become exposed and

act as a foam breaker if any occurs when the vacuum is applied.



According to [4] the number of baffles needed per tank is 4. A given relationship of

18

7.0 Other Equipment Design and Sizing

7.1 Condensers

7.1.1 Take-Off Condenser

Table 10: Specifications of our take-off condensers for our proposed plant [6]

Material 316 Stainless Steel

Type Shell & tube heat exchanger

Straight tube, Fixed tubesheet shell & tube heat exchanger

Features Rated for 225 PSI and 450 oF on shellside, 150 PSI and 450 oF on tube side Surface Area 103 ft2

Length 5 ft

Diameter 8 inches Number of Passes 1

The take-off condenser which is used for glycols is sized from the heat balance giving the condenser surface area. The surface area was calculated to be 98 ft2. A condenser meeting our requirements was found at ITT Standard and was chosen with a surface area of 103 ft2.

7.1.2 Methanol Condenser

Table 11: Specifications of our take-off condensers for our proposed plant [6]

Material 316 Stainless Steel

Type Shell & tube heat exchanger

Straight tube, Fixed tubesheet shell & tube heat exchanger

Features Rated for 225 PSI and 450 oF on shellside, 150 PSI and 450 oF on tube side Surface Area 144 ft2

Length 7 ft

Diameter 8 inches Number of Passes 1

The methanol condenser is sized the same way from the heat balance and a surface area of 144 ft2 was calculated. A condenser which fits our sizing requirements was chosen from ITT Standard. It is the same type of condenser as the take-off condenser except of different size. A sample calculation for sizing of the take-off condenser is shown below.

𝑄 = 𝑈𝐴 ∆𝑇1− ∆𝑇2 𝑙𝑛∆𝑇1 ∆𝑇₂ ∆𝑇1= 𝑇𝑖𝑛 𝑔𝑙𝑦𝑐𝑜𝑙𝑠 − 𝑇𝑜𝑢𝑡 𝑤𝑎𝑡𝑒𝑟 = 205℃ − 48℃ = 157℃ ∆𝑇₂ = 𝑇_{𝑜𝑢𝑡 𝑔𝑙𝑦𝑐𝑜𝑙𝑠} − 𝑇_{𝑖𝑛 𝑤𝑎𝑡𝑒𝑟} = 70℃ − 20℃ = 50℃

19 𝑈 = 0.35 𝑘𝑊 𝑚2_{∙ ℃} 𝑄_{𝑠𝑒𝑛𝑠} = 𝑀_{𝑔𝑙𝑦𝑐𝑜𝑙𝑠}𝐶𝑝_𝐷𝐸𝐺 𝑇_{𝑖𝑛 𝑔𝑙𝑦𝑐𝑜𝑙𝑠} − 𝑇_{𝑜𝑢𝑡 𝑔𝑙𝑦𝑐𝑜𝑙𝑠} 0.2 + 𝑀_{𝑔𝑙𝑦𝑐𝑜𝑙𝑠}𝐶𝑝_𝑃𝐺 𝑇_{𝑖𝑛 𝑔𝑙𝑦 𝑐𝑜𝑙𝑠} − 𝑇_{𝑜𝑢𝑡 𝑔𝑙𝑦𝑐𝑜𝑙𝑠} 0.8 𝑄_{𝑙𝑎𝑡𝑒𝑛𝑡} = 𝑀_{𝑔𝑙𝑦𝑐𝑜𝑙𝑠} × 𝐻𝑣 𝐷𝐸𝐺 + 𝐻𝑣𝑃𝐺 𝑄 = 𝑄𝑠𝑒𝑛𝑠 + 𝑄𝑙𝑎𝑡𝑒𝑛𝑡 2 𝑕𝑟 × 3600_𝑕𝑟𝑠 = 300 𝑘𝑊 𝐴 = 𝑄 𝑈 ∆𝑇1− ∆𝑇2 𝑙𝑛∆𝑇1 ∆𝑇₂ = 300 𝑘𝑊 0.35 _𝑚𝑘𝑊_{2∙ ℃} 157℃ − 50℃ 𝑙𝑛157℃_50℃ = 9.17𝑚2

7.2 Packed Tower

An insulated packed bed tower was selected since the pressure drop in this column is minimal. Also, the separation of methanol and PG is relatively simple since their volatilities significantly vary. The saddle configuration was chosen for packing because they have increased surface area, are commonly manufactured out of ceramics, and have increased hydrodynamics during low pressure operation. Table 12 below shows the various packing specifications required to operate the packed column at total reflux. [7]

Table 12: Column Packing Specifications

Fill Factor 360.89 m-1

Surface Area 250 m2/m3

Size 1 Inch

Orientation Random

Type Berl Saddles

Material Ceramic

Vendor Norton

The minimum tower requirements were calculated using scale-up methods from the pilot plant column as well as the Fenske and Underwood equations for the minimum number of trays and

minimum reflux ratio, respectively.[8] [9] The minimum requirements along with the steady state calculations, determined in Aspen, are shown in Table 13.

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Table 13: Packed Bed Column Minimum and Steady State Requirements

Nmin 2 Nreal 4 Rmin 6.59 R 9.89 HETP 1.64 ft Diameter 3 ft Length 10 ft Condenser Duty 34.19 kW

The Fenske Equation, shown below, was used to determine the minimum number of trays with the specified distillate and bottoms composition, xD and xB, along with the relative volatilities, αAVG, as

per Aspen.

𝑁𝑚𝑖𝑛 =

log ⁡ 𝑥𝐷

1−𝑥𝐷 1−𝑥𝐵𝑥𝐵

log αAVG − 1 (1) The Underwood Equation, Equation 2, is evaluated by solving for θ in equation 3 using trial and error methods and the same values which were used in the Fenske Equation with a known flow rate q. 𝑅𝑚𝑖𝑛 = 𝛼_𝛼𝑖𝑥𝑖𝐷

𝑖−𝜃 − 1 (2) 𝑞 = 𝛼_𝛼𝑖𝑥𝑖𝐹

𝑖−𝜃+ 1 (3) The real number of trays is twice the minimum, where every tray is 1.64 feet in length, plus the condenser accounts for the approximate column length of 10 feet also taking into account a safety factor. A safety factor of at least 10% above the number of stages determined should be incorporated. [8]

The inlet PG and methanol stream will be fed into the bottom of the column since no reboiler is required. The column will be operated near 70% flooding and separate the required methanol from PG over the entire 5 hour transesterfication reaction.

The reflux drum will be a horizontal tank with an elliptical head used to feed condensed methanol back to the packed column. The volume was determined by assuming a length to diameter ratio of 2, using the volume flow rate from the condenser to determine diameter when the tank is at half capacity with a 5 minute hold-up time.

21

Table 14: Reflux Drum Specifications Based on 5 Minute Hold-up Levels at Half Capacity

Volume 18.68 ft3

Diameter 2.5 ft

Length 5 ft

The sump vessel was sized using a similar method as the reflux drum, however the PG flow rate from the bottom of the column was used to determine diameter.

Table 15: Sump Vessel Specifications Based on 5 Minute Hold-up Levels at Half Capacity

Volume 20.80 ft3

Diameter 2.5 ft

Length 5 ft

The sump and reflux drum diameters and lengths were rounded to a common tank size as they would be ordered.

7.3 Vessels

7.3.1 Raw Material Storage

The raw materials propylene glycol (PG), diethyl glycol (DEG), and dimethyl terephthalate (DMT) are stored in two tanks each. The reason for using two tanks for storage of each raw material instead of one larger tank is because it allows more flexibility in scheduling for shipments and maintenance in emergencies. This will reduce any downtime in the process which is essential for profitability. Sizing and specifications are provided in table 16 below.

Table 16: Sizing and specification for raw material storage tanks [10] [11]

Storage Vessels

Propylene Glycol Diethyl Glycol

Dimethyl Terephthalate TK-101A TK-101B TK-102A TK-102B TK-103A TK-104B Tank Type Vertical Fixed Roof Horizontal Tank Vertical Fixed Roof

Material Carbon Steel Carbon Steel Stainless Steel

Capacity 25,000 galls 7,500 galls 30,000 galls

Diameter (ft) 16 9 12

Height (ft) 26 - 47.5

Side Length (ft) - 14 -

Total Length (ft) - 16.6 -

Storage Time (days) 15 15 15

Heating Surface (ft2)

-

-

1252

Agitator Motor (hp)

-

-

7.5

22

DMT is stored in molten liquid form above its melting temperature of 140 0C in heated and insulated storage tanks at 165 0C. Due to the high temperature and the possibility of corrosion, the tank is to be made of stainless steel. The two tanks have 6-inch fiberglass insulation all around, two heating coils with hot oil flowing through them, and an agitator shaft with two impellers running at 40 rpm for uniform temperature [11]. Caution should be used when handling the molten DMT as it can cause thermal burns. PG presents no unusual problems and with a low melting point, heating is not necessary. DEG however has a melting point of -10 0C and in the cold winters, there is a risk for DEG to solidify. Therefore, the tank will have 6-inch fiber glass insulation all around it to keep it from reaching the melting point. The diagram below shows the DMT tank design schematic.

Figure 7: Storage tank design schematic for our molten DMT [11]

The sizing of the tanks was done by calculating the amount of raw material required in 30 days (60 batches) in gallons which is then divided by two since we’re using a two tank system. A third of the tank space is left empty for the nitrogen blanket. When the raw materials shipment arrives, the tank will be filled to two-thirds of its capacity and the remainder will be filled into the second tank. The

shipments arrive in intervals of 15 days (twice a month) so by the time the next shipment of raw materials arrive, there will be enough space in the tanks for storage. The table below shows the scheduling of the shipments with the amount ordered.

Table 17: Shipping and storage schedule for proposed plant

29st (last month) 12th (current month) 14th (current month) 14th (current month) 29th (current month)

DMT 31,500 galls 30,000 galls 31,500 galls

DEG 5,000 galls 5,000 galls 5,000 galls

23

The tank dimensions were determined by using an online calculator [10] with a length to

diameter ratio of about 1.5. All vessel dimensions in the plant were determined this way except for DMT and the product storage silos which were determined from capacity charts. A sample calculation for storage tank sizing is shown below for DMT.

𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑦 = 5156 𝑘𝑔

𝑏𝑎𝑡𝑐𝑕 × 2𝑏𝑎𝑡𝑐𝑕𝑑𝑎𝑦 × 30 𝑑𝑎𝑦𝑠

5.11_{𝑔𝑎𝑙𝑙𝑜𝑛𝑠}𝑘𝑔 ÷ 2 𝑡𝑎𝑛𝑘𝑠 = 30,270 𝑔𝑎𝑙𝑙𝑜𝑛𝑠

7.3.2 Receivers

During transesterification, once the methanol is separated from the glycols it is completely condensed into a liquid and held in a receiver tank before being sent to the storage tank. Since all the methanol has been condensed, we do not require cooling water for the receiver and there will be two in total for each of the two reactors. Sizing was done by calculating the volumetric flow of methanol per batch and multiplying it by a factor of 1.25 for extra space. Calculations for this are shown below.

𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑦 =1674 𝑘𝑔 𝑏𝑎𝑡𝑐𝑕

3.0_{𝑔𝑎𝑙𝑙𝑜𝑛𝑠}𝑘𝑔 × 1.25 = 698 𝑔𝑎𝑙𝑙𝑜𝑛𝑠

During polycondensation, the glycol vapours are condensed to a liquid (95%) by a condenser, which is further condensed afterwards, in two condensate receivers (refer to Figure 3: P&ID) for the remaining 5% vapour. Service water from the cooling tower at ambient temperature will be used as the cold water supply for condensing. Sizing for the primary receiver was done by taking 95% of the take-off condenser glycol over 2 hours since most of the glycols are pulled within that time while the secondary receiver is 5%. They are sized for two batches in case of any downtime in the process. Calculations for this are shown below with a table under it showing the specifications of the receivers.

0.95 × 2014_{𝑏𝑎𝑡𝑐𝑕}𝑘𝑔 2 𝑕𝑟 0.8 × 4.23 + 0.2 × 3.22 _{𝑔𝑎𝑙𝑙𝑜𝑛𝑠}𝑘𝑔 × 2 𝑏𝑎𝑡𝑐𝑕 × 1.25 = 600 𝑔𝑎𝑙𝑙𝑜𝑛𝑠 0.05 × 2014_{𝑏𝑎𝑡𝑐𝑕}𝑘𝑔 2 𝑕𝑟 0.8 × 4.23 + 0.2 × 3.22 _{𝑔𝑎𝑙𝑙𝑜𝑛𝑠}𝑘𝑔 × 2 𝑏𝑎𝑡𝑐𝑕 × 1.25 = 28 𝑔𝑎𝑙𝑙𝑜𝑛𝑠

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Table 18: Sizing and specification for all receivers

Receivers (Glycols - PC Stage) Receivers (MeOH - TC Stage)

Primary Receivers

Secondary

Receivers Primary Receivers V-202A V-202B V-203A V-203B V-201A V-201B Material Stainless Steel Stainless Steel Stainless Steel

Capacity (galls) 600 30 700

Height (ft) 6 2.4 7

Diameter (ft) 4.5 1.6 4.5

7.3.3 Methanol Storage and Glycol Recycle

Methanol from the two receivers (V-201A/B) will be stored in a single tank rather than in two tanks like everything else. Methanol is a flammable liquid so storage is to be kept away from sources of ignition or sparks. The storage tank is sized for 30 days of storage with a third of the tank space allowed for the nitrogen blanket. Sizing calculations for the methanol tank is shown below.

𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑦 =1674 𝑘𝑔 𝑏𝑎𝑡𝑐𝑕 3.0_{𝑔𝑎𝑙𝑙𝑜𝑛}𝑘𝑔 × 2𝑏𝑎𝑡𝑐𝑕 𝑑𝑎𝑦 × 30 𝑑𝑎𝑦 × 1.5 = 50,220 𝑔𝑎𝑙𝑙𝑜𝑛𝑠

During polycondensation when the glycols go through the primary and secondary receivers, they will be sent to a glycol recycle tank which will recycle the glycols back into the process for the next batch. This glycol recycle tank is sized for 3 days. This seems like a lot but in case anything goes wrong in the process, we don’t have to worry about the tank overflowing. Sizing calculations for the glycol recycle tank is shown below with a table under it showing the specifications.

𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑦 = 2014 𝑘𝑔 𝑏𝑎𝑡𝑐𝑕 0.8 × 4.23 + 0.2 × 3.22 𝑘𝑔_{𝑔𝑎𝑙𝑙𝑜𝑛}× 2 𝑏𝑎𝑡𝑐𝑕 𝑑𝑎𝑦 × 3 𝑑𝑎𝑦 × 1.15 = 3450 𝑔𝑎𝑙𝑙𝑜𝑛𝑠

Table 19: Sizing and specifications for methanol storage and glycol recycle tanks

Methanol Glycol Recycle

TK-201 V-204

Tank Type Vertical Fixed Roof Horizontal Tank Material Carbon Steel Carbon Steel Capacity 50,000 galls 3,500 galls

Diameter (ft) 20 7 Height (ft) 33 - Side Length (ft) - 11 Total Length (ft) - 13.13 Storage Time (days) 30 3

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7.3.4 Product Storage Silos

The polyester resin product will be collected in welded carbon steel silos. There will be two silos sized to store two weeks of product each, this will allow one silo to be filled while the other can be used to fill super sacks for shipping. Also, there will be a third silo that will be used to store any

off-specification product (deviation from our target molecular weight) which is sized assuming 10% of our resins produced in a month will be off-specification. Later on, the off-specification products will be mixed in with the rest of marketable products in order to homogenize them so that they can be sold. Calculations for sizing of the two main silos (TK-301A/B) are shown below with a table under it showing the specifications of all silos. The silo capacities in the table are a little higher than calculated because they were taken from a capacity chart and it is beneficial to have the extra space.

𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑦 = 5669 𝑘𝑔 𝑏𝑎𝑡𝑐𝑕 ×2 𝑏𝑎𝑡𝑐𝑕𝑑𝑎𝑦 × 30 𝑑𝑎𝑦 5.11 + 4.23 + 3.92 3 𝑔𝑎𝑙𝑙𝑜𝑛𝑘𝑔 ÷ 2 = 38,477𝑔𝑎𝑙𝑙𝑜𝑛𝑠 = 5985 𝑓𝑡2

Table 20: Sizing and specifications for polyester resin storage silos [12]

Polyester Resin Product TK-301A TK-301B TK-302 Tank Type Shop Welded Silo (45o hopper)

Material Carbon Steel

Capacity 6,426 ft3 2,396 ft3

Diameter (ft) 14 12

Height (ft) 48 28

26

7.4 Downstream Equipment

7.4.1Cooling belt system

The Sandvik double roll feed cooling belt [13] is used after the reactors to transport and cool the polymer. The Polymer is discharged from the bottom of the reactor, between two rollers, that flatten the polymer to a thickness of 2 mm. The polymer is then pulled by the steel cooling belt of width 1.02 m and 8 m length as water is sprayed on the underside of the belt to cool the melt. To cool the polymer to ambient temperature of 25 oC, approximately 16,300 kg of water is required.

The average velocity would be around 0.031 m/s for the cooling belt. The flakes will then be removed from the belt by a scraper and broken by a breaker roller before going to the pulveriser.

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7.4.2 Disintegration equipment

The broken flakes will deposit into the feed bag of a Hammer-Mill pulveriser to be further broken down to smaller particulates. The pulveriser can take 1200 to 3000 kg/hr of the polymer which is within our parameters [14]. After the polymer is broken further down, the particulates will fall onto a conveyer belt. The pulveriser contains a recycling and filter unit so that when particles are not of a pre-determined size the filter would stop them from leaving the system and would be recycled back into the hammer mill to be broken down further.

Figure 9: Hammer Mill-30 Pulveriser [14]

After the pulveriser, the granules are deposited onto a cleated inclined conveyor belt angled at 60 degrees of approximately 55 meters (180 ft) in length to put the solid into a silo to be mixed with different batches to create uniformity.

Table 21: Specifications of Selected Processing Equipment

Section

Dimensions

Cooling belt

8 by 1.02 m (26 by 3 ft)

Pulveriser

1.45 by 0.93 by 1.69 m (4.75 by 2.8 by 5.5 ft)

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7.5 Utility Equipment

7.5.1 Hot Oil Utility

In the plant, Fulton’s four pass vertical coil thermal fluid heater will be used to provide the required heating by hot oil to the reactor and the two heated DMT storage tanks. From the heat balance, a heat output of 1,700,000 Btu/h was calculated to be the maximum heat required at peak demand and a suitable thermal fluid heater design was selected from the capacity chart.

Transesterification required more heat than polycondensation so the heat output was found by summing the heat required for TE stage and the heat required for the raw DMT tanks since that will be the maximum heat (capacity) required at once. Sizing calculations for this are shown below.

Heat in TE Reaction 𝑄𝑟𝑒𝑞 = 𝑀𝑚𝑒𝑡𝑎𝑙𝐶𝑝𝑚𝑒𝑡𝑎𝑙 + 𝑀𝑐𝑕𝑒𝑚𝑖𝑐𝑎𝑙 𝐶𝑝𝑐𝑕𝑒𝑚𝑖𝑐𝑎𝑙 𝑇2− 𝑇1 𝑄𝑟𝑒𝑞 = 5027.7 𝑘𝑔 × 0.15 𝑘𝐽 𝑘𝑔 ∙ ℃+ 10847.6 𝑘𝑔 × 2.2 𝑘𝐽 𝑘𝑔 ∙ ℃ 160 − 100 ℃ = 1,477,133 𝑘𝐽



100

o

C was found to be the initial temperature because the DMT is already heated

𝜏 = 𝑀𝑚𝑒𝑡𝑎𝑙𝐶𝑝𝑚𝑒𝑡𝑎𝑙 + 𝑀𝑐𝑕𝑒𝑚𝑖𝑐𝑎𝑙 𝐶𝑝𝑐𝑕𝑒𝑚𝑖𝑐𝑎𝑙 𝑈𝐴 𝑙𝑛 𝑇 − 𝑇1 𝑇 − 𝑇₂ 𝜏 = 5027.7 𝑘𝑔 × 0.15_{𝑘𝑔 ∙ ℃ + 10847.6 𝑘𝑔 × 2.2}𝑘𝐽 _{𝑘𝑔 ∙ ℃}𝑘𝐽 1750_{𝑚2∙ 𝑕 ∙ ℃ × 27.67𝑚}𝑘𝐽 2 𝑙𝑛 175 − 100 ℃ 175 − 160 ℃ = 0.818 𝑕𝑟𝑠 𝑄_{𝑇𝐸 𝑟𝑥𝑛} = 𝑄𝑟𝑒𝑞 𝜏 × 3600= 1,477,133 𝑘𝐽 0.818 𝑕𝑟 × 3600_𝑕𝑟𝑠 = 501.6 𝑘𝑊 Heat in DMT Storage Tanks

𝑄_{𝑙𝑜𝑠𝑠} = 𝑀_𝐷𝑀𝑇𝐶𝑝_𝐷𝑀𝑇 0.05 × 𝑇 ∗ 5% 𝑕𝑒𝑎𝑡 𝑙𝑜𝑠𝑠 (𝑙𝑖𝑓𝑒𝑡𝑖𝑚𝑒 𝑖𝑛 𝑡𝑎𝑛𝑘) 𝑄_{𝑙𝑜𝑠𝑠} = 143,088.6 𝑘𝑔 × 2.2 𝑘𝐽 𝑘𝑔 ∙ ℃ 0.05 × 165℃ = 2,597,038 𝑘𝐽 𝑄𝐷𝑀𝑇 = 𝑄_{𝑙𝑜𝑠𝑠} 𝑙𝑖𝑓𝑒𝑡𝑖𝑚𝑒 × 24_{𝑑𝑎𝑦 × 3600}𝑕 _𝑕𝑠× 2 𝑄_𝐷𝑀𝑇 = 2,587,038 𝑘𝐽 8 𝑑𝑎𝑦 × 24_{𝑑𝑎𝑦 × 3600}𝑕 _𝑕𝑠× 2 = 7.49 𝑘𝑊 Total Heat Capacity

29

𝑄_{𝑐𝑎𝑝𝑎𝑐𝑖𝑡𝑦} = 509.1 𝑘𝑊 = 1,737,121𝐵𝑡𝑢 𝑕𝑟

Natural gas will be used as fuel in the thermal fluid heater to heat the hot oil which runs through the heating coils along the diameter of the heater. A schematic of the thermal fluid heater is provided below showing how the heating happens in the interior.

(1) Top mounted burner

Top mounted burner design with special cone design produces a “narrow” long flame. By keeping the flame away from the inner row of coils it avoids flame impingement on the coils.

(2) Fluid inlet and outlet

Fluid travels through a continuous closed loop system. The fluid is pumped through the coils, to the fluid outlet, and continues on through the entire system to the users.

(3) All safety and operating

controls

They are located in one central control panel.

(4) Fan air inlet

It is used for combustion

30

The specifications for the thermal fluid heater is provided in the capacity charts shown in the table below. We will use the 0240 model which has a heat output capacity of 2,400,000 Btu/h. This is more than enough to provide for our heating.

Table22: Specifications for the four pass Fulton vertical coil thermal fluid heater [1]

7.5.2 Cooling Tower Utility

The use of a cooling tower in the plant will eliminate the need to rely solely on municipal water. This requires the plant to only treat the make-up water instead of a constant treatment if only using the municipal water. The cooling tower will be used for cooling the process water to 20 degrees C. This water will be used by the following units as cooling water: E201AB, E202AB, E203AB, V201AB, V202AB and V203AB as can be seen in the P&ID. It was determined that the cooling process can be

accomplished by using water, which prevents the usage of refrigerated water or refrigerated glycols which will save money in operating costs. The parameters relating to the cooling tower can be seen below. The cooling tower used will be an induced-draft tower utilizing a counterflow arrangement as suggested in Perry’s Chapter 12 to be the most common and the most thermodynamically efficient. The

31

make-up water was calculated as a sum of the drift water, evaporated water, and the purge water; to ensure the required water level is maintained

Table 23: Cooling tower specifications

Total Required Cooling Water 59.3 USGPM

Design Parameter 89.0 USGPM

Cooled Water 68 F

Process Water 118 F

Maximum Temperature for design 98 F

Make Up Water Neded 6.6 USGPM

Tower Radius 4.8 ft

Tower Height 21.0 ft

Fan Power 3.2 kW

* Design Parameters are calculated by using the guides and graphs shown in Perrys Handbook Chapter 12

32

7.6 Pumps

Pumps were sized with respect to the required flow rate and net positive suction head, with pump charts used as a reference to determine the power requirements. All pumps are centrifugal with the exception of the vacuum pump, which is a rotary piston pump. Centrifugal pumps were selected due their simplicity, capacity range, and ease of operation and maintenance [15].

Both piping and pumping are constructed with ANSI 304 grade stainless steel, except sections handling propylene glycol, which is corrosive and requires more durable ANSI 316 grade steel. As DEG is toxic, pumps handling any quantity of this fluid should be hermetically sealed to reduce the likelihood of exposure. Pumps and lines handling molten DMT are heat traced to prevent solidification in the lines.

Table 24: Pump Specifications

Pump Function P & ID Reference Name Capacity per Pump (m3/h) Power per Pump (kW) Additional Considerations To Feed Storage

To DEG stores P-101 34.0 19 Hermetically sealed

To PG stores P-103 37.9 19 Made of ANSI 316 grade steel

To DMT stores P-105 37.9 19 Heat-traced pump and line

To Reactor

DEG feed P-102 A & B 0.629 2 Hermetically sealed

PG feed P-104 A & B 3.43 2 Made of ANSI 316 grade steel

DMT feed P-106 A & B 4.29 2 Heat-traced pump and line

To Methanol Storage Pumps methanol from TE stage to store

P-201 A & B 1.13 2 Vacuum Pump

Generates vacuum for PC stage

P-202A & B 4 22 Rotary piston type pump To Glycol Storage

Pumps glycols from PC stage to store

P-203 A & B 1.8 2 Hermetically sealed, made of ANSI 316 grade steel

Glycol Recycle

Recycled glycol feed to reactor

P-204 1.71 2 Hermetically sealed, made of ANSI 316 grade steel

Cooling Tower

Cooling water pump P-401 A & B 20.2 30 Heater

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8.0 Process Safety

8.1 Hazardous Conditions

There are several hazardous conditions that must be considered in the plant ranging from operational, thermal process, and raw material hazards. The potential hazards in the plant include ignition of flammable liquids causing fires or explosions, eye and skin irritation with the possibility of causing blindness, inhalation of airborne vapours causing central nervous system depression, thermal burns, etc. The majority of the hazards just mentioned come from contact with methanol as well as to a lesser extent, molten dimethyl terephthalate (DMT), diethyl glycol (DEG), propylene glycol (PG), and the hot oil.

8.2.1 Plant Classification (electrical safety)

The entire plant along with the control and lab room will be explosion proof. The facility will be able to handle class I, division 2, groups C and D chemicals [22]. This will be done by the use of explosion and static proof pumps for transporting of chemicals. All vessels/reactors in the plant will be well ventilated with a nitrogen blanket on top in order to prevent airborne vapours which increase the risk of ignition, especially for methanol with its low flash point. Class I refers to hazards through the presence of

flammable gases and vapours such as natural gas and methanol vapours in this case. Division 2 refers to abnormal conditions and groups C and D chemicals include most of the usual class I chemical groups [22].

8.2.2 Operational Safety

The required wearing of the proper personal protective equipment (PPE) such as safety glasses, safety shoes, hard hats and leather gloves by the workers will greatly minimize the possibility of many of the hazards mentioned previously. This mainly applies for transporting of chemicals and work related to the hot oil unit. As mentioned previously, sufficient ventilation and nitrogen blanket will prevent any inhalation hazards from airborne vapours for the operators. The supervisor will have a large

responsibility in ensuring safety protocols (handling procedures, PPE, etc) are followed by the workers. The control instrumentation in the process will minimize any major hazards that can occur from process failure and since the plant has two of everything due to using a two reactor system, it provides redundancy and the process can still be ran efficiently while diagnosing any problems or hazards that arise. There will be fire alarms around the facility with fire extinguishers and emergency exits in case a fire breaks out. Eye wash stations will be placed near all chemical storage vessels and handling

areas/lab. MSDSes will be readily available in easily accessible areas for workers and weekly meetings on operational safety will take place in order to ensure the staff is well informed of all hazards. The table below lists important hazards and handling procedures for all materials used in the plant.

34

Table 25: Material hazards

Material Form Safe Handling Main Hazards

DMT Molten liquid  Do not handle near an open flame, heat or other sources of ignition.

 Use non-sparking tools when opening or closing containers

 Can cause thermal burns, handle the molten liquid with care (wear PPE)

 Exposure to powder or dusts may be irritating to eyes, nose and throat

 May form explosive dust/air mixtures if concentration of product dust is suspended in air

 May be ignited by heat, sparks or flames

PG Colourless

liquid

 Keep away from heat and other sources of ignition

 Ground all equipment containing material

 Hazardous in case of ingestion

 May cause irritation if exposed to skin or eyes

 Flammable at high temperatures

DEG Colourless

liquid

 Keep away from heat and other sources of ignition

 Ground all equipment containing material

 Harmful if swallowed

 May cause irritation if exposed to skin or eyes

 Flammable at high temperatures Methanol Colourless

liquid

 No smoking or open flame near handling areas

 Use explosion proof electrical equipment

 Ensure proper

grounding procedures

 Inhalation of air-borne

vapours can cause headaches, nausea, confusion, loss of consciousness, disgestive and visual disturbances and even death

 Moderately irritating to the skin (effects similar to those of inhalation)

 Swallowing small amounts could potentially cause blindness or death. Effects of sub lethal dose are nausea, headache, abdominal pain, vomiting and visual

disturbances

 Easily ignitable (fire or explosion), very low flash point, keep away from sources of ignition

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8.2.3 Thermal Process Safety

Any hazards that arise from the thermal process units such as the thermal fluid heater, reactors

and DMT tanks are at a minimum. Temperature controls will ensure operations are within

bounds and the process reaction is an endothermic, equilibrium reaction so there are no issues

that can arise. In case of any leaks that occur within these units, the control room will pick this

up and appropriate action will be taken.

8.3 Waste Disposal

There is limited waste produced in the plant. The DEG and PG byproducts are recycled back into

the reactor for the next batch and the methanol byproduct is stored and sold. Service water

used for cooling is recycled back into the cooling tower and the hot oil is recycled back in the

hot oil unit. The purge for all these recycled loops will require some form of treatment or

disposal. The cooling water will be treated according to regulations and then disposed of; the

DEG, PG and methanol will be disposed of by means of a waste disposal company

36

9.0 Floor Plan

C B -3 0 1 R -2 0 1 A R -2 0 1 B E -2 0 1 A E -2 0 1 B E -2 0 2 A E -2 0 2 B T -2 0 1 A T -2 0 1 A _{2 0 1 A}V V -2 0 1 A V -2 0 -2 A V -2 0 -2 B V -2 0 3 A V -2 0 3 B T K -1 0 3 A T K -1 0 3 B T K -1 0 2 B T K -1 0 2 A T K -1 0 1 A T K -1 0 1 A H M -3 0 1 T K -3 0 1 A T K -3 0 1 B T K -3 0 2 C B -3 0 2 C T -4 0 1 L a b C o n tro l R o o m P a rk in g R a il T ra ck s 5 2 ' 5 4 ' _{6 5 '} 5 8 '-6 " 4 7 ' -6 '’ 3 0 '-0 " 1 7 '-6 " 1 7 ' -6 '’ F -4 0 1 E x p lo s io n P ro o f A re a T a n k F a rm A re a N itro g e n N o n -E x p lo s io n P ro o f A re a N o n -E x p lo s io n P ro o f A re a

37

The lot size of the plant layout seen in figure 8 is approximately 2 acres; however additional land will be required to allow for acceptable commercial spacing. The explosion proof and non-explosion proof areas have been indicated on the diagram with the exception of the hot oil unit containment area, F-401, which will also be explosion proof.

Sarnia was chosen as the plant location since the area has housed large industrial ventures for decades and is considered to be international leaders in chemical production with access to continental railways and seaways. Consequentially, there is a large skilled industrial work force and the government is providing incentives to promote new growth in the area including endorsing environmentally friendly processes. The local government has provided several large business parks, including an additional 100 acres this year, to encourage new industrial growth. The price of land varies depending on several variables including accessibility to water and railway. The cost of land for required property with railway access is approximately $200,000 Canadian.

10.0 Economic Analysis

10.1 Capital Costs, Installation Costs and Expense/Fees

Table 26: Overall Capital Costs

Component Cost

Factor

Used

Cost

Direct Plant Cost

Equipment Cost

100

$5,831,367

Piping

0

0

Auxilary Systems &

Services

12

$699,764

Electrical

10

$583,137

Instrument and Control

10

$583,137

Civil Work

20

$1,166,273

Total Direct

$8,863,678

Indirect Costs

Engineering and

Supervision

12

$699,764

Contingency

10

$583,137

38

Table 27: Raw Material Prices & Costs

Propylene Glycol (PG) [16] Diethyl Glycol (DEG) [17] Dimethyl Terephthalate (DMT) [18] Methanol Total

FOB Contract price (US$/ton)

$1760.00

$1345.00

$1400.00

$350.00

Amount per batch

(ton/batch)

3.536

0.704

5.156

1.67

Cost per Batch (US$)

$6223.36

$946.88

$7218.40

$584.50

$14,389

Cost per Batch (CAD)

$6136.23

$933.62

$7117.34

$576.317

$14,187

Cost per Day (CAD)

$12272.47

$1867.25

$14234.68

$1152.634

$28,374

Cost per Month (CAD)

$368173.98

$56017.42

$427040.54

$34579.02

$851,232

Cost per year (CAD)

$3608104.98

$548970.72

$4184997.33 $338874.396

$8,342,073

39

Table 28: Equipment Capital Costs

Unit 1: Upstream

Capital

Cost

per

Unit ($)

Number

of units

Capital

Cost ($)

Tanks:

TK 101 A/B 108796

2

217592

TK 102 A/B

44496

2

88993

TK 103 A/B 255121

2

510243

Pumps:

P 101

85600

1

85600

P 102 A/B

28600

2

57200

P 103

74600

1

74600

P 104 A/B

19000

2

38000

P 105

85600

1

85600

P106 A/B

24900

2

49800

Unit 2: Processing

Reactor:

R 201 A/B

462407

2

924814

Exchanger:

E 201 A/B

46996

2

93992

E202 A/B

35825

2

71649

Column:

T 201 A/B

373389

2

746778

Tanks:

V 201 A/B

45007

2

90015

V 202 A/B

41476

2

82953

V-203 A/B

8477

2

16954

V 204

16992

1

16992

TK 201

135813

1

135813

Pumps:

P 201A/B

19000

2

38000

P 202 A/B

79400

2

158800

P 203 A/B

22500

2

45000

P 204 A/B

22500

2

45000

Unit 3: Downstream

Equipment:

CB 301

376601

1

376601

HM 301

56287

1

56287

40

Silos:

TK 301 A/B 485538

2

971076

TK 302

185830

1

185830

Transport:

CB 302

17600

1

17600

Unit 4: Utilities

Equipment:

F 401

183650

1

183650

CT 401

89334

1

89334

Pumps:

P 401 A/B

61700

2

123400

P 402 A/B

76600

2

153200

Capital Cost

(equipment)

$5,831,367

*All capital costs for the equipment were calculated using Don Woods’s Bare Modulus Method, except where noted in Section 6. This method allows for considerations for piping, material, pressure,

installation and any other major considerations specific to each case.

10.2 Operating Costs

Table 29: Plant Operating Costs

Water

Total Cost (Hourly, after first 6000

m^3) $2.007 $/h

Total Cost (Daily, after first 6000 m^3) $48.163 $/day

Total Cost (Annually) $24148.46 $/yr

Oil

Total Cost (Annually) $41571.66 $/yr

Natural Gas

Total Cost (Hourly) $12.332 $/h

Total Cost (Daily) $295.959 $/day

Total Cost (Annually) $87011.91 $/yr

Electricity

Total Cost (Daily) $769.158 $/day

Total Cost (Annually) $226067.50 $/yr

Labour

Total Cost (Hourly) $132.38 $/h

Total Cost (Daily) $3177.12 $/day

Total Cost (Annually) $934073.3 $/yr

Total Operating Cost

41

The electricity and natural gas rates used for this estimate were the 2009 rates for the city of

Toronto. Water rates used were the 2010 rates for the city of Toronto [19]. Labour costs were estimated using an online database of national salaries [20]. Lighting cost was estimated by comparing the size of our plant to a lighting cost estimate for another industrial manufacturing plant [21].

10.3 Income statement over 12 years accounting period

An analysis was completed on the financials for the proposed plant and the data in the following table are the major conclusions.

1. The project will produce an estimated 25 million dollars (Net Present Value) over 12 year plant life according to the profit loss statement seen in figure 11

2. The minimum to charge for the product for the project to break even; covering the cost of the loan, interest (5%; Prime +2%), and operating costs is $3.58/kg, see figure 13.

3. If the resin is sold at $5/kg, the lower end of the market value for a high quality polymer resin, the project will produce a 36% rate of return.

4. Varying the selling price from $5/kg to $7/kg changes the payback time from 3.5 to 1.5 years, see figure 12. A selling price of $5/kg allows for a reasonable payback time of 3 years and yields a NPV of $25M (using 5% interest) see figure 14.

5. Raw feed prices are the major expenditure for the plant; An increase of 20% in the raw feed prices increases the payback time from 3 years to 5 years at the recommended selling price, based on the conclusions above, see figure 15.

6. The breakdown of the selling price is shown in figure 17.

This is an income statement over 12 years for the proposed plant. The inputs for the income statement are based on the previously calculated values for capital costs, operating costs, and material costs. The tax rate is from the generally accepted accounting principles (GAAP).

42

43

Figure 12: Sensitivity Analysis on the selling price NPV vs selling price ($/kg) for a 5% interest rate for borrowing after 12 year plant life

10.3.1 Sensitivity Analysis on the selling price

Figure 15: NPV vs year for varying selling prices

-60 -40 -20 0 20 40 60 80 100 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 N PV ($M ill io n s) Selling Price ($/kg) -20 -10 0 10 20 30 40 50 60 70 0 2 4 6 8 10 12 N PV Period (Years) $5/kg $6/kg $7/kg

44

10.3.2 Sensitivity Analysis on the raw feed prices

Figure 136: NPV vs year for increasing raws cost

10.4 Acid Route Alternative Analysis

The acid route alternative was also analysed to determine the impact that it would have on the bottom line. Main considerations when determining the alternative route analysis were:

 Only slightly less capital than in the DMT route. The acid route does not require methanol condensers, a packed column, glycol condenser, or methanol storage tanks. However, the acid route will be run under pressure, which will require the equipment used to be pressure rated, increasing the cost.

 The cost of acid route raw materials is less expensive which is the major difference between the two methods

 The product produced is the exact same quality and is therefore sold for the same price in the market.

A comparison between the two routes based on NPV and selling-point breakdown are available in Figures 17 and 18, respectively.

-15 -10 -5 0 5 10 15 0 2 4 6 8 10 12 N PV ($M ill io n s) Period (years) Raw Price (100%) Raw Price (105%) Raw Prices (110%)

45

Figure 14: A comparison of the acid route vs the DMT route, based on NPV.

Figure 15: Selling price breakdown; showing profit, unit cost of manufacturing, and raw costs

-20

-10

0

10

20

30

40

50

0

5

10

NPV

($

m

ill

ion

s)

Period (years)

Transesterification

Route

Direct Esterification

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Acid Route (Alternative) DMT Route (Proposed)

$/k

g

sold Profit

Unit costs Raw costs