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

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 (1,2g propylene-diethylene-terephthalate) resin with a Mn of 6000 mol 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) Raw Material Manufacturing Profit

Ester Route $2.75 $0.65 $1.60

Acid Route $1.92 $0.82 $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 2

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 8.0

Process Safety ................................................................................................................................. 33 3

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 13.0 References .......................................................................................................................................... 48

4

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.

5

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. Reactor Temperature (C)

250 200 150 100 50 0 0

2

4

6 Time (h) 8

10

12

14

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

Reactor Pressure (mmHg)

800 700 600 500 400 300 200 100 0 0

2

4

6

8

10

12

14

Time (h) 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 ↑ Monomer ↔ poly (1, 2-propylene-diethylene-terephtahalate) + glycol ↑

6

(1) (2)

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 ↑ Monomer ↔ poly(ethylene terephthalate)

(3) (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

Specification Process type Feed Catalyst required? Reactor configuration Process description

Reaction time Reaction conditions Vacuum required? Byproducts Average DP

Direct Esterification Process Batch Purified terephthalic acid, ethylene glycol Yes Two stirred reactors in series, followed by multi-stage polymerizer Catalyzed esterification in primary reactor to 90% conversion, then esterification in second reactor to 98% conversion, then heated and pressurized in polymerizer 9 hours 245 - 275 oC; 0.133 - 275 kPa Yes Water 200

Transesterification Process Batch DEG, PG, DMT Yes Single stirred reactor Transesterification of DMT with glycols to form intermediate oligomers, followed by catalyzed polycondensation 11 hours 215 oC, 0.133 kPa Yes Methanol 100

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 High initial capital cost due to additional equipment needed for redundancy

Redundancy Maximize use of downstream equipment Two products can be made in the same plant 7

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 1 2 3 4

Stream Information DMT PG DEG Product

Batch Charges A (Kg) 5156 3536 704 5669

Batch Charges B (Kg) 5156 2263 386 5669

Table 4: Physical properties of all materials in the plant

Material Properties Dimethyl Terephthalate (DMT)

Diethylene Glycol (DEG)

C10H10O4 153 Solid/Molten Liquid 140 194.19 o 1.2 at 20 C (solid) White Slight to none

C4H10O3 138 Liquid (clear viscous) -8 106.12 1.12 Colourless. Clear Odorless

Density (g/cm3) Toxology (acute effects mg/kg)

1.35 3200 Propylene Glycol (PG)

1.036 12565 Methanol (MeOH)

Chemical formula Flash Point (oC) Form Melting Point (oC) Molecular Weight (g/mol) Vapour Pressure (mm Hg) Colour Odour Density (g/cm3) Toxology (acute effects mg/kg)

C3H8O2 99 Liquid (oily liquid) -59 76.1 1.035 Colourless. Clear Odorless 1.118 20000

CH3OH 11 Liquid -98 32.04 97.7 Colourless. Clear Mild alcohol odour 0.7918 5628

Chemical formula Flash Point (oC) Form Melting Point (oC) Molecular Weight (g/mol) Vapour Pressure (mm Hg) Colour Odour

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. 8

Table 5: Operating Schedule

Task Raws charging Heating up Transesterification stage Polycondensation stage Discharging Resin cooling Resin crushing Resin grinding Batch Complete Total cycle time:

Time for Reactor A (hours) Start time Duration 0600 3 0900 1 1000 5 1500 6 2100 3.5 2100 3.5 2130 3.5 2130 3.5 0100

Time for Reactor B (hours) Start time Duration 2100 3 0000 1 0100 5 0600 6 1200 3.5 1200 3.5 1230 3.5 1230 3.5 1600

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.

9

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

R 201 A/B Glycols

1590.14

R 201 A/B Methanol

Column:

2014 5668.88

E 201 A/B

1674

1674

3.46

Water

E 202 A/B

2014

2014

9.29

Water

0.6987

Water

0.0369

Water

T 201 A/B Total Feed

16740

T 201 A/B Methanol

1674

T 201 A/B Glycols Tanks:

Oil

1674

R 201 A/B Product Exchanger:

21.82

15066

V 201 A/B

1674

V 202 A/B Total Feed

2014

V 202 A/B To Storage

1913

V 202 A/B To V-203 A/B V-203 A/B

1674

101 101

V-204

2014

TK 201

1674

10

101

15.4

Unit 3: Downstream Equipment:

CB 301

5668.88

5668.88

HM 301

5668.88

5668.88

4.067

Chilled Water

155.83 29.83

CB 302 CB 303 Silos:

TK 301 A/B

5668.88

TK 302 Unit 4: Utilities Equipment:

F 401 CT 401

Pumps Unit 1:

Capacity (m^3/h)

13.4 3.19 *duty for both pumps where applicable*

DEG

19

3.43

DEG

4

34.01

PG

19

0.629

PG

4

37.855

DMT

19

P106 A/B

4.29

DMT

4

P 201A/B

1.13

Methanol

4

P 202 A/B

4

Air (For Vacuum)

44

P 203 A/B

1.8

Glycols

4

1.71

Glycols

2

P 401 A/B

22

Water

60

P 402 A/B

20.2

P 103 P 104 A/B P 105

P 204 Unit 4:

Material Pumped

Oil Water

37.855

P 101 P 102 A/B

Unit 2:

22 13.48

Oil

Misc. Lighting and Instrumentation

60

13.75

11

5.0 Process Control 5.1 Preliminary P&ID diagram 14

1A

TK-102A

P-101

15A

6A 1B

TK-102B

TRC

TRC

202A

202B

7B V-201A

P-201A 10A

T-201A 2A

TK-101A

FRC 201A

5A

TK-101B

P-201B 10B

3A

FRC 201B

5B

V-202B

8B PRC 202B

TRC 201B

12B

11B

R-201A

TK-103A

P-202B

E-202B 9B

V-202A

PRC 202B

TRC 201A

V-203B

E-203B

8A

P-104B

R-201B 11A

P-106A

12A C-201

4A

4B

3B

TK-103B

V-201B

T-201B

E-202A 9A

2B

P-105

V-203A

P-202A

E-203A

P-104A P-103

15B

6B

7A

P-102B

TK-201

E-201B

E-201A P-102A

P-203B

V-204

P-106B

13

P-203A P-204

F-401 LRC 401

TK-301A

CT-401

P-402A

CB-301

P-401A

WATER SUPPLY P-402B

CB-302 TK-301B 17

16

P-401B

HM-301

Figure 3: P&ID

12

TK-302

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

1 A/B 2 A/B 3 A/B 4 A/B 5 A/B 6 A/B 7 A/B 8 A/B 9 A/B 10 A/B 11 A/B 12 A/B 13 14 15 A/B 16 17

DEG

Start-up Material Requirements (kg)

Normal Operation Material Requirements (kg) 704

322

PG

3536

2005

DMT

5156

5156

Reactor Product

5669

5669

16738

16738

1674

1674

Packed Column Feed Packed Column MeOH Packed Column MeOH Reflux Packed Column PG Take-off Condensor Glycol Glycol Receiver Feed

----

----

15064

15064

2014

2014

101

101

Glycol Receiver 1 Outlet

1913

1913

Glycol Receiver 2 Outlet

101

101

Glycol Purge

----

----

0

1913

Methanol Byproduct

1674

1674

Crusher Feed

5668

5668

Storage Feed

5668

5668

Glycol Recycle to Reactor

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]

13

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.

14

6.0 Reactor Design and Sizing 6.1 Reactor Design Table 8: Reactor Design Specifications

Volume [m3] Internal Diameter [m] Height [m] Number of Ports Number of Instrument Ports Material Of Construction Jacketed Vacuum rated Light/Camera equipped

10 2.2 2.8 8 4 NiCrMo stainless steel Yes Yes, up to 4mmHg Yes, for remote viewing capabilities.

Figure 5: Reactor Dimensions

15

Glycols to Column (2 inches) Glycols from Column (2 inches) Nitrogen (1 inch)

Agitator Inlet (5 inches)

Manhole (20 inches)

DEG Loading (3 inches) DMT Loading (6 inches) PG Loading (5.5 inches)

Figure 6: Reactor Overhead (to scale)

6.2 Ports On top of reactor:

1. 2. 3. 4. 5. 6. 7. 8.

PG loading 5.5” DEG loading 3” DMT (molten) loading 6” Agitator shaft inlet 5” Manhole – 20” ID equipped with a sightglass, also used for solid catalyst loading MeOH/Glycol outlet 2” Glycol from column 2” Nitrogen port 3”

Sensor Probes needed:

1. 2. 3. 4.

Temperature sensor Pressure sensor Viscosity sensor (see section 5b) Level sensor

16

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 Agitator speed [RPM] Number of Impellers Blade Type Number of Baffles Baffle Width [m] Baffle Clearance [m] Agitator Height [m] Agitator Diameter [m] Agitator Shaft Diameter





15.4 24 and 42 (dual setting) 3 P4/45 4 0.122 0.025 Located at 0.7, 1.4, 2.1 meter from the bottom 1 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 baffle width versus viscosity is given in the documentation.

17

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 Type Features Surface Area Length Diameter Number of Passes

316 Stainless Steel Shell & tube heat exchanger Straight tube, Fixed tubesheet shell & tube heat exchanger Rated for 225 PSI and 450 oF on shellside, 150 PSI and 450 oF on tube side 103 ft2 5 ft 8 inches 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 Type Features Surface Area Length Diameter Number of Passes

316 Stainless Steel Shell & tube heat exchanger Straight tube, Fixed tubesheet shell & tube heat exchanger Rated for 225 PSI and 450 oF on shellside, 150 PSI and 450 oF on tube side 144 ft2 7 ft 8 inches 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 = 𝑇𝑖𝑛 𝑔𝑙𝑦𝑐𝑜𝑙𝑠 − 𝑇𝑜𝑢𝑡 ∆𝑇2 = 𝑇𝑜𝑢𝑡

𝑔𝑙𝑦𝑐𝑜𝑙𝑠

∆𝑇1 − ∆𝑇2 ∆𝑇 𝑙𝑛 ∆𝑇1 2

𝑤𝑎𝑡𝑒𝑟

= 205℃ − 48℃ = 157℃

− 𝑇𝑖𝑛 𝑤𝑎𝑡𝑒𝑟 = 70℃ − 20℃ = 50℃ 18

𝑈 = 0.35 𝑄𝑠𝑒𝑛𝑠 = 𝑀𝑔𝑙𝑦𝑐𝑜𝑙𝑠 𝐶𝑝𝐷𝐸𝐺 𝑇𝑖𝑛 𝑔𝑙𝑦𝑐𝑜𝑙𝑠 − 𝑇𝑜𝑢𝑡

𝑔𝑙𝑦𝑐𝑜𝑙𝑠

𝑘𝑊 𝑚2 ∙ ℃

0.2 + 𝑀𝑔𝑙𝑦𝑐𝑜𝑙𝑠 𝐶𝑝𝑃𝐺 𝑇𝑖𝑛 𝑔𝑙𝑦 𝑐𝑜𝑙𝑠 − 𝑇𝑜𝑢𝑡

𝑔𝑙𝑦𝑐𝑜𝑙𝑠

0.8

𝑄𝑙𝑎𝑡𝑒𝑛𝑡 = 𝑀𝑔𝑙𝑦𝑐𝑜𝑙𝑠 × 𝐻 𝑣 𝐷𝐸𝐺 + 𝐻 𝑣 𝑃𝐺 𝑄= 𝑄

𝐴= 𝑈

𝑄𝑠𝑒𝑛𝑠 + 𝑄𝑙𝑎𝑡𝑒𝑛𝑡 𝑠 = 300 𝑘𝑊 2 𝑕𝑟 × 3600 𝑕𝑟 300 𝑘𝑊

=

∆𝑇1 − ∆𝑇2 ∆𝑇 𝑙𝑛 ∆𝑇1 2

0.35

= 9.17𝑚2

𝑘𝑊 157℃ − 50℃ 157℃ 𝑚2 ∙ ℃ 𝑙𝑛 50℃

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 Surface Area Size Orientation Type Material Vendor

360.89 250 1

-1

m 2 3 m /m Inch

Random Berl Saddles Ceramic 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.

19

Table 13: Packed Bed Column Minimum and Steady State Requirements

Nmin Nreal Rmin R HETP Diameter Length

2 4 6.59 9.89 1.64 3 10

Condenser Duty

34.19

ft ft ft 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−𝑥 𝐷

1−𝑥 𝐵 𝑥𝐵

log α AVG

−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 = 𝑞=

𝛼 𝑖 𝑥 𝑖𝐷 𝛼 𝑖 −𝜃 𝛼 𝑖 𝑥 𝑖𝐹 𝛼 𝑖 −𝜃

−1

+1

(2) (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.

20

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

Volume Diameter Length

18.68 2.5 5

3

ft ft 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 Diameter Length

20.80 2.5 5

3

ft ft 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

Tank Type Material Capacity Diameter (ft) Height (ft) Side Length (ft) Total Length (ft) Storage Time (days) Heating Surface (ft2) Agitator Motor (hp) Agitator Height (ft)

Propylene Glycol TK-101A TK-101B Vertical Fixed Roof Carbon Steel 25,000 galls 16 26 15

Diethyl Glycol TK-102A TK-102B Horizontal Tank Carbon Steel 7,500 galls 9 14 16.6 15

Dimethyl Terephthalate TK-103A TK-104B Vertical Fixed Roof Stainless Steel 30,000 galls 12 47.5 15

-

-

1252 7.5 1.5

21

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

DMT DEG PG

29st (last month) 31,500 galls 5,000 galls 25,000 galls

12th (current month) 30,000 galls

14th (current month)

14th (current month)

5,000 galls 25,000 galls

22

29th (current month) 31,500 galls 5,000 galls 25,000 galls

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𝑕 ×2 × 30 𝑑𝑎𝑦𝑠 𝑏𝑎𝑡𝑐𝑕 𝑑𝑎𝑦 ÷ 2 𝑡𝑎𝑛𝑘𝑠 = 30,270 𝑔𝑎𝑙𝑙𝑜𝑛𝑠 𝑘𝑔 5.11 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. 𝑘𝑔 𝑏𝑎𝑡𝑐𝑕 𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑦 = × 1.25 = 698 𝑔𝑎𝑙𝑙𝑜𝑛𝑠 𝑘𝑔 3.0 𝑔𝑎𝑙𝑙𝑜𝑛𝑠 1674

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. 𝑘𝑔 0.95 × 2014 𝑏𝑎𝑡𝑐𝑕 2 𝑕𝑟

𝑘𝑔 0.8 × 4.23 + 0.2 × 3.22 𝑔𝑎𝑙𝑙𝑜𝑛𝑠

× 2 𝑏𝑎𝑡𝑐𝑕 × 1.25 = 600 𝑔𝑎𝑙𝑙𝑜𝑛𝑠

𝑘𝑔 0.05 × 2014 𝑏𝑎𝑡𝑐𝑕 2 𝑕𝑟 0.8 × 4.23 + 0.2 × 3.22

𝑘𝑔 𝑔𝑎𝑙𝑙𝑜𝑛𝑠

23

× 2 𝑏𝑎𝑡𝑐𝑕 × 1.25 = 28 𝑔𝑎𝑙𝑙𝑜𝑛𝑠

Table 18: Sizing and specification for all receivers

Receivers (Glycols - PC Stage)

Material Capacity (galls) Height (ft) Diameter (ft)

Primary Receivers V-202A V-202B Stainless Steel 600 6 4.5

Receivers (MeOH - TC Stage)

Secondary Receivers V-203A V-203B Stainless Steel 30 2.4 1.6

Primary Receivers V-201A V-201B Stainless Steel 700 7 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. 𝑘𝑔 𝑏𝑎𝑡𝑐𝑕 𝑏𝑎𝑡𝑐𝑕 𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑦 = ×2 × 30 𝑑𝑎𝑦 × 1.5 = 50,220 𝑔𝑎𝑙𝑙𝑜𝑛𝑠 𝑘𝑔 𝑑𝑎𝑦 3.0 𝑔𝑎𝑙𝑙𝑜𝑛 1674

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𝑕 × 3 𝑑𝑎𝑦 × 1.15 = 3450 𝑔𝑎𝑙𝑙𝑜𝑛𝑠 𝑑𝑎𝑦

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

Methanol TK-201

Glycol Recycle V-204

Tank Type Material

Vertical Fixed Roof Carbon Steel

Horizontal Tank Carbon Steel

Capacity Diameter (ft) Height (ft) Side Length (ft) Total Length (ft) Storage Time (days)

50,000 galls 20 33 -

3,500 galls 7 11 13.13

30

3 24

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 offspecification 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 =

𝑘𝑔 2 𝑏𝑎𝑡𝑐𝑕 × × 30 𝑑𝑎𝑦 𝑏𝑎𝑡𝑐𝑕 𝑑𝑎𝑦 ÷ 2 = 38,477𝑔𝑎𝑙𝑙𝑜𝑛𝑠 = 5985 𝑓𝑡 2 𝑘𝑔 5.11 + 4.23 + 3.92 3 𝑔𝑎𝑙𝑙𝑜𝑛

5669

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

Polyester Resin Product TK-301A TK-301B TK-302 Tank Type Material Capacity Diameter (ft) Height (ft) Storage Time (days)

Shop Welded Silo (45o hopper) Carbon Steel 6,426 ft3 14 48 15

25

2,396 ft3 12 28 30

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.

Figure 8: Double roll feeder cooling belt [13]

26

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 predetermined 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 Cooling belt Pulveriser Conveyor belt

Dimensions 8 by 1.02 m (26 by 3 ft) 1.45 by 0.93 by 1.69 m (4.75 by 2.8 by 5.5 ft) 31 by 1 m (102 by 3 ft) 27

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 = 𝑀𝑚𝑒𝑡𝑎𝑙 𝐶𝑝𝑚𝑒𝑡𝑎𝑙 + 𝑀𝑐𝑕𝑒𝑚𝑖𝑐𝑎𝑙 𝐶𝑝𝑐𝑕𝑒𝑚𝑖𝑐𝑎𝑙 𝑇2 − 𝑇1 𝑘𝐽 𝑘𝐽 𝑄𝑟𝑒𝑞 = 5027.7 𝑘𝑔 × 0.15 + 10847.6 𝑘𝑔 × 2.2 𝑘𝑔 ∙ ℃ 𝑘𝑔 ∙ ℃



160 − 100 ℃ = 1,477,133 𝑘𝐽

100oC was found to be the initial temperature because the DMT is already heated

𝑀𝑚𝑒𝑡𝑎𝑙 𝐶𝑝𝑚𝑒𝑡𝑎𝑙 + 𝑀𝑐𝑕𝑒𝑚𝑖𝑐𝑎𝑙 𝐶𝑝𝑐𝑕𝑒𝑚𝑖𝑐𝑎𝑙 𝑇 − 𝑇1 𝑙𝑛 𝑈𝐴 𝑇 − 𝑇2 𝑘𝐽 𝑘𝐽 5027.7 𝑘𝑔 × 0.15 + 10847.6 𝑘𝑔 × 2.2 𝑘𝑔 ∙ ℃ 𝑘𝑔 ∙ ℃ 𝜏= 𝑙𝑛 𝑘𝐽 1750 2 × 27.67𝑚2 𝑚 ∙𝑕∙℃ 𝜏=

𝑄𝑇𝐸 𝑟𝑥𝑛 =

175 − 100 ℃ = 0.818 𝑕𝑟𝑠 175 − 160 ℃

𝑄𝑟𝑒𝑞 1,477,133 𝑘𝐽 = = 501.6 𝑘𝑊 𝜏 × 3600 0.818 𝑕𝑟 × 3600 𝑠 𝑕𝑟

Heat in DMT Storage Tanks 𝑄𝑙𝑜𝑠𝑠 = 𝑀𝐷𝑀𝑇 𝐶𝑝𝐷𝑀𝑇 0.05 × 𝑇 𝑄𝑙𝑜𝑠𝑠 = 143,088.6 𝑘𝑔 × 2.2

∗ 5% 𝑕𝑒𝑎𝑡 𝑙𝑜𝑠𝑠 (𝑙𝑖𝑓𝑒𝑡𝑖𝑚𝑒 𝑖𝑛 𝑡𝑎𝑛𝑘) 𝑘𝐽 0.05 × 165℃ = 2,597,038 𝑘𝐽 𝑘𝑔 ∙ ℃

𝑄𝑙𝑜𝑠𝑠 ×2 𝑕 𝑠 𝑙𝑖𝑓𝑒𝑡𝑖𝑚𝑒 × 24 × 3600 𝑑𝑎𝑦 𝑕 2,587,038 𝑘𝐽 = × 2 = 7.49 𝑘𝑊 𝑕 𝑠 8 𝑑𝑎𝑦 × 24 × 3600 𝑑𝑎𝑦 𝑕

𝑄𝐷𝑀𝑇 = 𝑄𝐷𝑀𝑇

Total Heat Capacity 𝑄𝑐𝑎𝑝𝑎𝑐𝑖𝑡𝑦 = 𝑄𝑇𝐸 𝑟𝑥𝑛 + 𝑄𝐷𝑀𝑇 = 501.6 𝑘𝑊 + 7.49 𝑘𝑊 = 509.1 𝑘𝑊

28

𝑄𝑐𝑎𝑝𝑎𝑐𝑖𝑡𝑦 = 509.1 𝑘𝑊 = 1,737,121

𝐵𝑡𝑢 𝑕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

(2) Fluid inlet and outlet (3) All safety and operating controls (4) Fan air inlet

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. 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. They are located in one central control panel. It is used for combustion

Figure 10: Fulton’s vertical coil thermal fluid heater design with descriptions [1]

29

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 30

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

31

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

To Feed Storage To DEG stores To PG stores To DMT stores To Reactor DEG feed PG feed DMT feed To Methanol Storage Pumps methanol from TE stage to store Vacuum Pump Generates vacuum for PC stage To Glycol Storage Pumps glycols from PC stage to store Glycol Recycle Recycled glycol feed to reactor Cooling Tower Cooling water pump Heater Heating oil pump

P & ID Reference Name

Capacity per Pump (m3/h)

Power per Pump (kW)

P-101 P-103 P-105

34.0 37.9 37.9

19 19 19

Hermetically sealed Made of ANSI 316 grade steel Heat-traced pump and line

P-102 A & B P-104 A & B P-106 A & B

0.629 3.43 4.29

2 2 2

Hermetically sealed Made of ANSI 316 grade steel Heat-traced pump and line

P-201 A & B

1.13

2

P-202A & B

4

22

Rotary piston type pump

P-203 A & B

1.8

2

Hermetically sealed, made of ANSI 316 grade steel

P-204

1.71

2

Hermetically sealed, made of ANSI 316 grade steel

P-401 A & B

20.2

30

P-402 A & B

22.0

30

32

Additional Considerations

Insulated pump and line

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.

33

Table 25: Material hazards

Material DMT

Form Molten liquid

PG

Colourless liquid

Safe Handling Main Hazards  Do not handle near an  Exposure to powder or dusts open flame, heat or may be irritating to eyes, nose other sources of and throat ignition.  May form explosive dust/air  Use non-sparking tools mixtures if concentration of when opening or closing product dust is suspended in containers air  Can cause thermal  May be ignited by heat, burns, handle the sparks or flames molten liquid with care (wear PPE)  

DEG

Colourless liquid

 

Methanol

Colourless liquid

  

Keep away from heat and other sources of ignition Ground all equipment containing material

 

Keep away from heat and other sources of ignition Ground all equipment containing material No smoking or open flame near handling areas Use explosion proof electrical equipment Ensure proper grounding procedures

 



 

 



34

Hazardous in case of ingestion May cause irritation if exposed to skin or eyes Flammable at high temperatures Harmful if swallowed May cause irritation if exposed to skin or eyes Flammable at high temperatures 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

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

35

9.0 Floor Plan

E -2 0 2 A

52'

R -2 0 1 B 2 0T1- A

T K -1 0 2 B

E -2 0 2 B

T K -1 0 3 B

V201A

E x p lo s io n P ro o f A re a HM 301

C B -3 0 2

1 7 '-6 " R -2 0 1 A 2 0T1- A

T K -1 0 3 A

V203B

E -2 0 1 A

C B -3 0 1

T K -1 0 2 A

N itro g e n

V202B

V201A

E -2 0 1 B

V202A

V203A

4 7 ' -6 '’ Lab

T a n k F a rm A re a

C o n tro l R o o m 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

P a rk in g

Figure 101: Floor plan

36

58'-6"

T K -1 0 1 A

30'-0"

T K -1 0 1 A

F -4 0 1

65'

17' -6'’

Rail Tracks

C T -4 0 1

54'

T K -3 0 1 B

T K -3 0 1 A

T K -3 0 2

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

Factor Used

Component Cost Direct Plant Cost Equipment Cost Piping Auxilary Systems & Services Electrical Instrument and Control Civil Work

Cost 100 0

$5,831,367 0

12 10 10 20

$699,764 $583,137 $583,137 $1,166,273

Total Direct

$8,863,678

Indirect Costs Engineering and Supervision Contingency

12 10

Total Capital Costs

$699,764 $583,137 $10,146,578

37

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) Amount per batch (ton/batch)

$1760.00

$1345.00

$1400.00

$350.00

3.536

0.704

5.156

1.67

Cost per Batch (US$) Cost per Batch (CAD)

$6223.36 $6136.23

$946.88 $933.62

$7218.40 $7117.34

$584.50 $576.317

$14,389

$12272.47

$1867.25

$14234.68

$1152.634

$28,374

$368173.98

$56017.42

$427040.54

$34579.02

$851,232

$3608104.98

$548970.72

$4184997.33 $338874.396

$8,342,073 $338,874

Cost per Day (CAD) Cost per Month (CAD) Cost per year (CAD) Revenue/ year (methanol)

38

$14,187

Table 28: Equipment Capital Costs

Unit 1: Upstream

Tanks: TK 101 A/B TK 102 A/B TK 103 A/B Pumps:

Capital Cost per Number Capital Unit ($) of units Cost ($) 108796 2 217592 44496 2 88993 255121 2 510243

P 101 P 102 A/B P 103 P 104 A/B P 105 P106 A/B

85600 28600 74600 19000 85600 24900

1 2 1 2 1 2

85600 57200 74600 38000 85600 49800

R 201 A/B

462407

2

924814

Exchanger:

E 201 A/B E202 A/B

46996 35825

2 2

93992 71649

Column:

T 201 A/B

373389

2

746778

Tanks:

V 201 A/B V 202 A/B V-203 A/B V 204 TK 201

45007 41476 8477 16992 135813

2 2 2 1 1

90015 82953 16954 16992 135813

Pumps:

P 201A/B P 202 A/B P 203 A/B P 204 A/B

19000 79400 22500 22500

2 2 2 2

38000 158800 45000 45000

376601 56287

1 1

376601 56287

Unit 2: Processing Reactor:

Unit 3: Downstream Equipment:

CB 301 HM 301

39

Silos:

TK 301 A/B TK 302

Transport: Unit 4: Utilities Equipment:

Pumps:

485538 185830

2 1

971076 185830

CB 302

17600

1

17600

F 401 CT 401

183650 89334

1 1

183650 89334

61700 76600

2 2

123400 153200

P 401 A/B P 402 A/B

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) Total Cost (Daily, after first 6000 m^3) Total Cost (Annually) Oil Total Cost (Annually) Natural Gas Total Cost (Hourly) Total Cost (Daily) Total Cost (Annually) Electricity Total Cost (Daily) Total Cost (Annually) Labour Total Cost (Hourly) Total Cost (Daily) Total Cost (Annually) Total Operating Cost Annual

40

$2.007 $48.163 $24148.46

$/h $/day $/yr

$41571.66

$/yr

$12.332 $295.959 $87011.91

$/h $/day $/yr

$769.158 $226067.50

$/day $/yr

$132.38 $3177.12 $934073.3

$/h $/day $/yr

$1312873

$/yr

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).

41

Figure 11: Accounting statement for the plant based on a 5% and $5/kg selling price

42

100 80

NPV ($Millions)

60 40 20 0 -20

1.5

2.5

3.5

4.5

5.5

6.5

7.5

8.5

-40 -60

Selling Price ($/kg)

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

70 60 50

NPV

40 30

$5/kg

20

$6/kg

10

$7/kg

0 -10 0 -20

2

4

6

8

10

Period (Years)

Figure 15: NPV vs year for varying selling prices

43

12

10.3.2 Sensitivity Analysis on the raw feed prices 15 NPV ($Millions)

10 5

Raw Price (100%)

0 -5 0

2

4

6

8

10

12

Raw Price (105%) Raw Prices (110%)

-10 -15

Period (years)

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.

44

50

NPV ($ millions)

40 30 20

Transesterification Route

10

Direct Esterification

0

-10 0 -20

5

10

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

5 4.5 4

$/kg sold

3.5 3

Profit

2.5

Unit costs

2

Raw costs

1.5 1 0.5 0 Acid Route (Alternative)

DMT Route (Proposed)

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

45

11.0 Conclusions/Recommendations The plant design outlined in this report includes several unique aspects such as use of two reactors running off-cycle, and the use of molten DMT. Using selling price of 5 $/kg, which is at the low end of the market price, the plant design in this report yields a net present value of $25,400,000 over 12 years. Adjusting the selling price of the product towards 7 $/kg at the high end of the market yields a net present value of nearly $60,000,000. Due to the profitability of the plant in its current state and the flexibility of the outlined plant design, notably the ability to run two different products off-cycle should the market change significantly in the near future; it is recommended that further development of this project be approved.

46

12.0 Acknowledgments We wish to thank Dr M. Saban for his continued support throughout this term. Without the support and extensive knowledge in scale up design this report would have been significantly different. Thanks for a great term. We also wish to thank Y. Sanchez for his support with Aspen to size specific equipment needed to complete the report. Lastly, thanks to the team at XRCC for the tour of the Pilot Plant to help us gain some practical knowledge that helped greatly in determining the practicality of out suggestions. Team Magenta 4W4 Poly, 2011

47

13.0 References [1] Polyesters, Vol 12, Chemical Engineering 4W04 2010-2011. Provided by Dr. Saban [2] Dynatrol (2008) Viscosity Mesurement and Control Equipment [Online]. Available: http://dynatrolusa.com/products/dynatrol-viscosity-probe.htm *3+ “High efficiency hydrofoil agitators”; ProChem Inc. Mississauga, Ontario; Chemineer HT agitators *4+ “Baffle Sizing”, Hayward Gordon Ltd; Section TG6, page 6.01-6.12, July 2000. *5+ “Chemical process equipment: selection and design”; James R. Couper, W. Roy Penney, James R. Fair; Chapter 10: Mixing and Agitation; Elsevier Inc, 2010 [6] ITT Standard (2011). SSCF – stainless steel shell & tube heat exchangers. Standard Shell & Tube. Available: http://www.ittstandard.com/Tools/Portfolio/frontend/item.asp?type=9&size=0&lngDisplay=4&jPageNu mber=5&strMetaTag= [7]Couper, J., Penny, W., Fair, J., Walas, S. (2010). Chemical Process Engineering. Burlington, M.A., United States: Elsevier Inc. [8] Hoon, C., Ling, A. (2007). Distillation Column Selection and Sizing. Taman Tampio Utama, Malaysia: KLM Technology Group. [9] Geankoplis, C. (2003). Transportation Processes and Separation Process Principles. Upper Saddles River, N.J., United State: Pearson Education Inc. [10] Tank Connection, Tank Capacity Calculators, Water and Wastewater, 2004. http://www.waterandwastewater.com/resources/capacity_calculators/index.php [11] CEI Enterprises. Vertical Tanks for Modified Asphalt. Astec Industries, Inc. 2011 http://www.ceienterprises.com/downloads/cei_tankline.pdf [12] Lemanco. Lemanco Welded Silo Capacity Chart. Chief Industries, Inc. 2008 http://www.lemanco.com/html/silo_capacity_chart.html [13] Sandvik – your partners in melt granulation systems, Sandvik, 2007. http://www.sandvik.com/sandvik/0140/internet/s001664.nsf/3aa39d675f7cc278c12569b900513b28/c3 9993f6c144db58c12577c90035f40c/$FILE/PS-442-ENG-07.pdf [14] Mill Power Tech, Mill pulveriser, http://www.mill.com.tw/products-hammer-mill_english.htm [15] Girdhar, P., Moniz, O. (2004). Practical Centrifugal Pumps. Burlington, M.A., United States: Elsevier Inc. [16] ICIS Pricing. Propylene Glycol (PG) Prices and Pricing Information. Reed Business Information Ltd. 2011. http://www.icis.com/v2/chemicals/9076442/propylene-glycol/pricing.html [17] CMAI. Ethylene Glycol, Oxide & Derivatives Market Report. CMAI Global. 2010 48

www.cmaiglobal.com/Marketing/Samples/EOEG.pdf [18] ICIS Pricing. Dimethyl Terephthalate (DMT) Prices and Pricing Information. Reed Business Information Ltd. 2011 http://www.icis.com/v2/chemicals/9075278/dimethyl-terephthalate/pricing.html

[19] City of Toronto Website, http://www.toronto.ca/invest-in-toronto/utilities.htm [20] Payscale for Employers, http://www.payscale.com/hr/default?cmpid=70140000000Xsa6 [21] ReliablePlant Website, http://www.reliableplant.com/Read/28285/How-must-costs-run-equipment [22] United States Department of Labor. Hazardous (Classified) Locations, Osha. http://www.osha.gov/doc/outreachtraining/htmlfiles/hazloc.html

49