Sulphur Degassing

By:

Sulphur Degassing

CHEETAH CONSULTING:

Akshay Sonpal Al Abed-Rabbo Travis McLeod

Fourth Year Chemical Engineering Students

Department of Chemical Engineering

University of Saskatchewan

2007 - 2008

CHEETAH Consulting

Department of Chemical Engineering

University of Saskatchewan

Saskatoon, Sk

April 7, 2008

Mr. Pok, Mr Boyd, Mr. Thomas

Suncor Energy Inc.

Oil Sands

Fort McMurray, AB

Enclosed is the final design report for the Sulphur Degassing project submitted by CHEETAH Consulting. The purpose of this report was to design and compare two commercially available technologies that were able to degas Sulphur and reduce the H2S concentration to 15 ppmw.

After research and design, the two methods were the DGAASS Process and Shell Global process. This report consists of detailed description and design of both processes, as well as, cost comparison. One process and selected and deemed as the better process based on various reasons outlined in the report. Finally, economic analysis was performed on the selected process.

By degassing the sulphur, the selling price of sulphur increases by $20 per tonne, which results in an increase in revenue of $4.5 Million per year. Thus, it gives a break-even period of 1 month for the project.

Members of CHEETAH Consulting would like to thank Suncor Energy for the opportunity to work on this project. It has been a great educational experience.

Sincerely,

Akshay Sonpal Al Abed-Rabbo Travis McLeod

i

ABSTRACT

Cheetah Consulting is a 3 member group of chemical engineers from the

University of Saskatchewan. The group members are Travis McLeod, Al Abed-

Rabbo, and Akshay Sonpal.

Cheetah Consulting was contracted by Suncor to design a sulphur degasification

process to lower the H2S concentration entrapped within molten sulphur from

300 ppmw to 15 ppmw. Suncor required a process which was already

commercially available and not in the research and development phase. The

main objective of this project was to compare and contrast two technologies

based on economics, potential size constraints, and ease of operability. The

technologies which were examined were the Shell Degasification Process and the

DGAASS Process.

As mentioned previously, there were two alternatives studied, each with their

own advantages and disadvantages. The Shell Degasification process took place

within a sulphur pit, which is an advantage because it requires no additional plot

space. Whereas, the major disadvantage would be the downtime with

ii

installation along with the associated time for maintenance and repair. The

DGAASS Process had several advantages, such as the ease of retrofitting for pre-

existing plants along with minimal residence time. The disadvantage of this

process is that it requires plant plot space.

Upon evaluation of the two proposed technologies, the DGAASS Process was

chosen as the most favorable specifically in terms of capital and operating costs

as well the constraint of physical size did not pose a problem for this process.

The installed cost for this process was approximately $183,000 with operating

cost of $99,000 per annum. The diameter of the contacting column was 5.2 ft and

a height of 20 ft. The design also included an air compressor, fin fan cooler and

feed pump. The economic analysis of this showed a discounted breakeven point

of about 1 month at 15%. This also established a net present worth for the project

of $18.9 million.

The safety analysis performed included a detailed HAZOP analysis, which

looked at potential safety hazards associated with the equipment in the design.

Also, the safety concerns of each chemical were looked at to make sure the

equipment was operating in a safe range and operator safety was ensured.

iii

AcknowledgementsCHEETAH Consulting would like to acknowledge and thank the following

people for their continuous help who made this project successful.

Mr. Joe Pok, Process Engineer

Suncor Energy

Mr. Ryan Boyd, Process Engineer

Suncor Energy

Mr. Thomas Thomas, Process Engineer

Suncor Energy

Dr. Wang, Assistant Professor

Department of Chemical Engineering

University of Saskatchewan

Dr. Evitts, Associate Professor

Department of Chemical Engineering

University of Saskatchewan

Dr. Nemati, Associate Professor

Department of Chemical Engineering

University of Saskatchewan

iv

TABLEOFCONTENTS Pg

1. INTRODUCTION.. 1 1.1 Company Overview 1 1.2 Project Overview..... 1 1.3 Project Objectives 2

2. LITERATURE SEARCH.. 4

3. OVERVIEW OF PROPOSED METHODS .. 7

3.1 Shell Degasification Process.. 7 3.2 DGAASS Process 8

4. QUALITATIVE DESCRIPTION OF SHELL PRCOESS. 9

4.1 Process Description... 9 4.2 Process Specifications 10

5. EQUIPMENT SIZING AND COSTS FOR SHELL PROCESS.. 12

5.1 Equipment Sizing.... 12 5.2 Equipment Costs.. 13 5.3 Operating Costs... 14

6. QUALITATIVE DESCRIPTION OF DGAASS .. 16

6.1 Process description.... 16 6.2 Process Specifications.. 17

7. EQUIPMENT SIZING AND COSTS FOR DGAASS.. 20 7.1 Equipment Sizing..... 20 7.2 Equipment Costs.... 21 7.3 Operating Costs... 22

8. COMPARISON OF THE TWO PROCESSES... 24

8.1 Cost Comparison. 24 8.2 Advantages and Disadvantages for DGAASS Process 25 8.3 Advantages and Disadvantages for Shell process 26 8.4 Final Decision. 27

9. ECONOMICS OF DGAASS.. 28 9.1 Introduction to the Economics.. 28

v

9.2 Revenues, Expenses, Depreciation and Taxation... 28 9.3 Rate of returns and Net Present Value 29

10. SAFETY CONSIDERATIONS 32

10.1 Introduction. .. 32 10.2 Chemicals... 32 10.3 Personal Protective Equipment 33 10.4 HAZOP 34

11. CONCLUSIONS. 35

12. RECOMENDATIONS... 37

REFERENCES. 38

APPENDIX A Shell process: Equipment Sizes and Costs Calculations...

II

APPENDIX B DGAASS Process: Equipment Sizes and Cost Calculations

XXIV

APPENDIX C DGAASS Economics..

XXIV

APPENDIX D HAZOP Analysis.

XXXIV

Appendix E MSDS Information...

XXXIX

vi

ListofFigures

Figure 1: Dimensions of existing sulphur pit ............................................................... 3

Figure 2: Process flow diagram of Shell Degasification Process ............................. 11

Figure 3: Process Flow Diagram for DGAASS process ........................................... 17

Figure 4: Mass Balance Around Sulphur Degassing Vessel .................................... 19

Figure 5: Discounted break even point for the sulphur degasification project. ... 30

Figure 6: The complete economic analysis over the 25 year period. ...................... 30

vii

ListofTables

Table 1: Operating Cost for Shell Degasification Process ........................................ 14

Table 2: Equipment sizes and costs for the Shell Degasification Process .............. 15

Table 3: Equipment Sizes and Costs for the DGAASS Process .............................. 23

Table 4: Operating Costs for D'GAASS Process.23

Table 5: Cost Comparison between D'GAASS and Shell Processes ....................... 24

Table 6: Cash Flow Analysis for DGAASS Process .............................................. XXV

Table 7: Income Statement for DGAASS Process ............................................. XXVIII

Table 8: Depreciation Effects for DGAASS Process ........................................... XXXI

Table 9: Discounted Break Even Point for DGAASS Process ......................... XXXIII

Table 10: HAZOP Analysis.XXXV

viii

NOMENCLATURE

Symbol Definition Units

A

Surface Area of Heat Exchanger

ft2

Apipe Area of pipe ft2

C Circumference ft

Cp Capital Cost $

Cp Specific Heat Capacity BTU/lbmole F

Dpipe Diameter of Pipe ft

Dtheo Theoretical Diameter ft

f Fanning friction factor

FINLET Flow Rate at the Inlet ft3/s

FOUTLET Flow Rate at the Outlet ft3/s

GHSV Gas Hourly Space Velocity h-1

g Gravity constant ft/s2

h Height ft

Ht Height of Column ft

Le Equivalent Length ft

L Length ft

m Mass Flow Rate lb/s

NRe Reynolds Number

Patm Atmospheric Pressure psia

Ppit Pressure at Bottom of Pit psia

ix

Pin Pressure at Inlet of Pump psia

Pout Pressure at Outlet of Pump psia

Pflow Pressure Drop in the Flow psia

Ppump Pressure Drop Across the Pump psia

Q Volumetric Flow Rate ft3/s

Q Heat Transfer Rate BTU/s

tDT Downtime h

TLM Logarithmic Mean Temperature F

T1 Temperature Tube Side F

T2 Temperature Shell Side F

U Overall Heat Transfer Coefficient BTU/ft2sF

Ub Bulk Velocity ft/s

Usg Specific Gravity Velocity Ft/s

Ut Total Velocity ft/s

v Velocity ft/s

V1 Volume for first compartment ft3

V2 Volume for second compartment ft3

VC Contact Volume ft3

VW

Working Volume ft3

VSparg Volume of the sparger column ft3

w Width ft

Ws Shaft Work BTU/s

Z Compressibility Factor

x

Greek Symbols

Pipe Roughness ft

i Intrinsic efficiency

Viscosity cP

l Density of the Liquid lb/ft3

g Density of the Gas lb/ft3

Residence Time h

1

1. INTRODUCTION

1.1 Company Overview

Suncor is a major North American energy producer company with over 6,500

employees. Their main operation is near Fort McMurray, Alberta, Canada, where

they extract and upgrade oil sands to high quality crude oil products and diesel

fuel. Furthermore, they produce natural gas in Western Canada. Suncors

downstream operations in Ontario and Colorado market their refined products

to commercial customers. During March 2008, Suncors oil sands facilities

averaged 248,000 barrels per day of production and they are targeting an average

oil sand production of 300,000 bpd in 2008.

1.2 Project Overview

Suncor base plant, which is located in Fort McMurray, is currently producing 600

long-tons/day of liquid sulphur from the Claus sulphur recovery unit. The

Sulphur is stored in a below grade sulphur pit and it contains 200 to 350 ppmw

of H2S partially dissolved in the form of polysulphides (H2Sx). The polysulphides

dissociate to H2S and Sx during the loading, agitation, and cooling. Afterwards,

the H2S evolves from the liquid sulphur and accumulates in the vapour space of

2

handling equipment. These issues can be overcome by degassing the sulphur

and reducing the concentration of H2S. By doing so, explosion hazard, toxicity,

and odour issues are overcome. There are many processes available for liquid

sulphur degasification. Some of which will be discussed in this report.

1.3 Project Objectives

CHEETAH Consulting was asked to design and compare two common, non-

catalytic, continuously operated, and commercially proven processes to degas

liquid sulphur and reduce the concentration of H2S from 300 ppmw to under

15ppmw. Afterwards, one process will be selected and recommended for

installation at the Suncor base plant. The comparison of the two processes will

include the following:

1. Economics: Capital costs including installation, as well as annual

operating costs.

2. Operability and control strategy: The ease and familiarity of operation

of each process.

3. Environmental concerns: Considering sulphur and H2S emissions

4. Safety: Considering possible hazards for each process.

The basis of the design is listed below:

The temperature of the sulphur in the pit is 315F

3

The product sulphur temperature after degassing will be 300 F

The target H2S/H2Sx in the product liquid sulphur will be < 15 ppmw

Suncor has limited plot space so the process must be relatively small.

The dimensions of the existing sulphur pit are shown in Figure 1 below:

Figure 1: Dimensions of existing sulphur pit

4

2. LITERATURE SEARCH

The scope of the project was to reduce the concentration of dissolved H2S in

molten sulphur from 300 ppmw to approximately 15 ppmw. CHEETAH

Consulting reviewed several sources to find which method or technique would

fulfill the above objective.

In todays high paced oil and gas industry, the manufacturing and production of

sulphur is becoming a very important factor. That being stated, CHEETAH

Consulting did some basic literature research to understand some of the general

properties of sulphur. For example, it was interesting to note that the boiling

temperature of sulphur was 883 F and a corresponding melting point

temperature of 241 F. These values are important to note during the designing

phase of any project to ensure unexpected phase changes do not occur. Another

factor which was examined was H2S. H2S is considered lethal if it is vented to

atmosphere at concentrations exceeding 400 ppmw, and also since the upper

explosion limit is generally 44 % by volume in air, it is imperative that it does not

exceed this particular value or combustion reactions may occur. Also the H2S

5

has a boiling point of -76 F and this temperature must not be exceeded due to

the similar reasons of sulphur. (Perry, 1997)

Currently in industry, there are several companies which produce molten

sulphur with variable amounts of dissolved H2S. As mentioned previously, this

is a huge environmental concern since the emission of H2S into the atmosphere

could essentially be lethal, and thereby new processes and technologies are

constantly being implemented through research and design to minimize this

threat. The sulphur, at any sour gas plant facility, is produced by means of the

Claus process. Upon producing sulphur, it is then typically placed in an

underground storage pit. Upon finding several articles on the latter, Cheetah

Consulting found that the most common method to degas H2S would be to inject

an inert chemical gas into the sulphur pit. Typical inert gases are the following:

Nitrogen, carbon dioxide, air, nitrogen plus steam, helium, nitrogen plus sulphur

dioxide, nitrogen plus nitrogen dioxide and finally helium plus 10 % ammonia

(Ismagilova, 2004). The inert gas which would be most favorable is primarily

based upon the duration of the residence time allowed to degas the sulphur.

Theoretically, ammonia would be the preferred inert gas to use since it uses the

least amount of residence time for H2S degasification to occur. However,

ammonia poses an environmental hazard and has thereby been discontinued.

For its replacement, air or nitrogen, has been utilized.

6

Besides, in-pit degasification of sulphur, there are other means of separation such

as using a simple separation or contacting column. This method essentially

reduces the concentration of the inlet H2S in the sulphur stream by mixing it in a

counter current column by purging of an inert chemical gas. These inert

chemical gases are similar to the in-pit degasification, and a common gas used is

air. Air is generally used since it is relatively cheap and readily available,

thereby making it the ideal choice for either of the methods.

7

3. PROPOSED METHODS

OVERVIEW

The two most widely used processes chosen which are capable of degassing the

liquid sulphur to a concentration below 15 ppmw are:

9 Shell Sulphur Degasification Process (licensed by Jacobs, Netherlands)

9 DGAASS Process (licensed by Goar, Allison and Associates)

3.1 Shell Degasification Process

The Shell process consists of a series of air sparging bubble columns immersed in

the liquid sulphur within the pit. The bubble columns are open at the top and

bottom to allow for circulation of sulphur and mixing with air. A more in depth

description of this process is included in section 4.0 in this report. The main

disadvantage of this process is that it takes place within the sulphur pit;

therefore, it will require significant downtime to install. An advantage is that it

does not require much plot space since it takes place in the pit. This would be

beneficial for Suncor since there is limited plot space available.

8

3.2 DGAASS Process

The DGAASS process consists of a vertical vessel in which pressurised air and

the undegassed sulphur flow counter-currently across the vessel. The process

degasses the sulphur through oxidizing some of the H2S and H2Sx to elemental

sulphur, followed by stripping the remaining H2S from the sulphur. A more in

depth description of this process is included in section 6.0 of this report. The

disadvantage of this process is that it would be difficult to install the vessel and

tie in with the existing equipment within the plot space. An advantage is that

Suncor is already operating a similar process in another portion of the plant so

they would be familiar with the operation methods.

9

4. QUALITATIVE DESCRIPTION

OF SHELL PRCOESS

4.1 Process Description

The Shell Degasification Process takes place within the confines of the sulphur

pit. The H2S is removed by agitating the liquid sulphur with air. The air is

bubbled through the liquid sulphur using a series of rectangular bubble columns

that are open on the top and bottom to ease the circulation process of liquid

sulphur. The removal of the H2S occurs in the following 3 step process:

1. A portion of the H2S that is dissolved evolves from the sulphur and is

carried to the vapor space.

H2S (dissolved) H2S (gas)

2. A portion of the H2Sx changes to dissolved H2S to so that equilibrium can

be maintained between H2S/H2Sx in sulphur.

H2Sx (bound) H2S (dissolved)

3. H2S reacts with the oxygen in the stripping air although the amount of

H2S that reacts is minimal.

10

H2S + O2 H2O + S

There is also sweep air introduced to the process to ensure the liquid sulphur is

circulated within the sulphur pit. For this process, the sulphur pit needs to be

segmented into two parts by using a weir. The first compartment is to allow

adequate residence time for the H2S to be removed from the liquid sulphur. The

second compartment of the pit contains the degassed sulphur that will be taken

to storage. This second part of the pit also has the responsibility of surge capacity

to keep continuous operation during downtime and maintenance. The H2S

removed with the stripping air will then be sent to an ejector were the waste gas

stream will be sent for disposal.

4.2 Process Specifications

For this process, the most important aspect is that the liquid sulphur product

contains no more than 15 ppmw of H2S to meet the product specifications. The

Shell Degasification Process recommends that three bubble columns be used in

the process, with each having identical dimensions. The air supplied in this

process is supplied using an air blower; however, the air must be preheated to

approximately 215 F so that there is minimal heat loss due to the contacting of

air and sulphur. This is to ensure that the liquid sulphur stays in its molten state.

Furthermore, the product pump must be able to deliver a flow rate of 600 long-

11

tons/day. Another requirement is that it be able to deliver it to a storage tank

3000 ft away and 50 ft high. The process diagram can be seen in Figure 2.

Figure 2: Process Flow Diagram of Shell Degasification Process

12

5. EQUIPMENT SIZING AND

COSTS FOR SHELL PROCESS

5.1 Equipment sizing

Using a recommendation of 20% contact volume to working volume ratio from

Suncor, the volume of each sparging column was determined. The total contact

volume required was 1416 ft3 for the three sparging columns and therefore the

required contact volume of each column would be 472 ft3. The height and width

of the sulphur pit are constraints on the size; therefore, to allow for circulation of

sulphur in the sulphur pit, the height was set to 4.5 ft and the width to 7.5 ft. That

said, the length of each column must be 14 ft.

The size of each compartment of the pit was determined so that the residence

time of 9 hours could be met as suggested by Ismagilovas article. The volume of

the first section of the pit was then determined to be 4825 ft3. This volume will

allow sufficient time for the sulphur to be degassed and meet the product

specifications of 15 ppmw. This therefore meant the volume of the second

compartment or surge compartment was 2256 ft3.

13

The shaft work of the centrifugal product pump was found to be 4.69 BTU/s

with an intrinsic efficiency of 46.4 %. These values were determined using

Ulrichs guidelines. A shell and tube heat exchanger was found to be an

acceptable way to heat the air before making contact with the liquid sulphur. The

surface area of this heat exchanger was determined to be 76.1 ft2. The main air

blowers shaft work was determined to be 6.92 BTU/s with the efficiency

assumed to be on the lower end at 65%.

5.2 Equipment Cost

Using Ulrich as an approximation to the installed cost of the equipment the Shell

process had a total cost of $705,000. The rectangular bubble columns were

estimated using Fig. 5.46 of Ulrich and had an installed cost of $195,000 each.

This figure was based on the diameter of the sparger; therefore, a theoretical

diameter was determined. This was done based on making the perimeter of the

rectangle into the circumference and thereby the diameter was determined. The

total cost of the sparging columns was $585,000. The main air blower that was

used in this process had an installed cost of $51,000 using Fig. 5.30 in Ulrich. The

centrifugal radial pump used to pump the degassed liquid sulphur to storage

would cost $41,000 based on Fig. 5.49 in Ulrich. The two shell and tube heat

14

exchangers used to heat the air entering and the gas mixture exiting was

approximately $28,000. The heat exchangers were based on Fig. 5.36 of Ulrich.

5.3 Operating Cost

The associated operating costs for this process were calculated to be $116,000 per

year. The maintenance and repair cost were to be 6% of the fixed capital cost and

therefore required $42,000 per year. The cost to run the product pump and main

air blower at a total of 11.8 BTU/s was determined to be $25,000 based on the

electricity costs. The addition of an extra operator would be required therefore

increasing the labor costs $49,000 per year based on Ulrichs recommendations.

Tables 1 and 2 show a summary costs and equipment sizing.

Table 1: Operating Cost for Shell Degasification Process

Operating Cost

Maintenance and Repairs $42,000 / year

Utility $25,000 / year

Labor $49,000/ year

Total : $116,000 /year

15

Table 2: Equipment sizes and costs for the Shell Degasification Process

Equipment Size Installed Cost

Bubble Column x 3 Volume = 472 ft3 $ 585,000

Heater x 2

(Shell and Tube)

Area = 76.1 ft2 $ 28,000

Blower 6.92 BTU/s $ 51,000

Product Pump 4.69 BTU/s $ 41,000

Total : $705,000

16

6. QUALITATIVE DESCRIPTION

OF DGAASS PROCESS

6.1 Process description

The DGAASS process is a relatively new process for degassing sulphur. The

process takes place within a vertical vessel. Using a compressor, air is

pressurized and fed into the bottom of the vessel. The sulphur is pumped from

sulphur pit at a rate of 600 long tons per day then cooled before contacting the

air. The cooling of sulphur before entering the vessel is required in order to

achieve an optimal H2S separation to lower the concentration to 15 ppmw in the

degassed sulphur. Inside the vessel, air and sulphur flow counter currently. A

process flow diagram is shown in Figure 3. The H2S and H2Sx are removed by

oxidization and stripping as shown in the reactions below:

H2S + O2 H2O + S

H2Sx + O2 H2O + Sx

The DGAASS process operates at elevated pressures to increase the partial

pressure of oxygen and concentration of dissolved oxygen in the liquid sulphur.

By increasing the concentration of oxygen, the kinetics of the oxidation reaction

is improved. Therefore, less air is required for stripping.

17

Figure 3: Process Flow Diagram for DGAASS process

The degassed sulphur exits the vessel and enters the knockout drum where the

liquids and vapors are separated. The liquid sulphur leaving the knockout drum

is then sent back to the sulphur pit. The vent gas leaving the knockout drum

contains very low concentration of H2S, SO2, and sulphur vapor. This stream is

either sent to the incinerator or to the sulphur recovery unit where it is used to

produce sulphur using the Claus process. That said, there is no sulphur emission.

18

Finally, the product sulphur stream, has a H2S concentration of 15 ppmw, is

heated and sent to storage.

6.2 Process Specifications

The sulphur in the pit is maintained at 315 F by steam coils to keep it in its

molten state. However, in order to achieve optimum degassing, the sulphur is

cooled to 285 F. The flow rate of sulphur is 600 long tons per day. In order to

calculate the minimum air flow rate required to sufficiently strip the H2S, a air-

to-sulphur ratio of 0.2 SCF/lb was used. This ratio was determined through

operational experience and was set by Suncor. Using this ratio, the flow rate of

air is set at 184 ft3/min. A close up of the vessel is shown in Figure 4.

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Figure 4: Mass Balance Around Sulphur Degassing Vessel

The operating pressure at the top of the vessel is set at 100 psig. The air must be

35 psig higher than the overhead pressure. This allows for pressure losses and

overcomes the head loss of sulphur in the vessel. The air is compressed to 135

psig prior to entering the vessel.

Molten Sulphur L in = 600 LTDx in = 300 ppmw H2S

AirG in =184ft3/miny in =0

Exit AirG out = 184 ft3/miny out = 6 ppmw H2S

Product SulphurL out = 600 LTDx out = 15 ppmw

20

7. EQUIPMENT SIZING AND

COSTS FOR DGAASS

7.1 Equipment Sizing

The equipment designed for the DGAASS process include: sulphur degassing

vessel, air cooler, feed pump, compressor, and knockout drum. All calculations

done for the design were performed using Ulrich.

The column diameter and height were calculated to be 5.2 ft and 20 ft

respectively. This column is relatively small so it should not have a conflict with

Suncors limited plot space. In order to design the pump, first the density of

molten sulphur was found at the feed temperature. Then, the shaft power was

calculated to be 3.1 BTU/s at an efficiency of 65%. The pump designed was a

centrifugal pump made from carbon steel.

The knockout drum is a horizontal drum made of carbon steel with diameter and

length of 6.4 inches and 2.13 feet. The diameter was found using correlations of

settling velocity provided in Ulrich. The air cooler was designed as a simple fin

21

fan air cooler. Using a power consumption of 0.19 BTU/ft2 and a surface area of

approximately 1000 ft2, the power of the air cooler was calculated to be 14.2

BTU/s. The size of the compressor was approximately 15.2 BTU/s.

7.2 Equipment Costs

All equipment costs calculated include the installation costs as well as any extra

secondary equipment used (pipes, valves, etc). The prices included were based

on estimated costs in 2004. Therefore, a correction factor was used to estimate the

costs to the realistic values in 2007. The total cost of equipment for the DGAASS

process was $183,000. The majority of the cost was for the degassing vessel.

Using the cost figures on page 387 of Ulrich, the vessel was estimated at $77,000.

The air cooler was estimated at $40,000 using figure 5.4 in Ulrich. The pump cost

was estimated at $40,000. Finally, the knockout drum and compressor were

estimated at $6,000 and $20,000 respectively.

22

7.3 Operating Costs

The associated operating costs for this process were calculated to be $99,000 per

year. The maintenance and repair cost were determined by using 6% of the fixed

capital cost and therefore was equal to $11,000 per year. The cost of utilities to

run the process was determined to be $39,000 per year based on the electricity

costs. Finally, a labor cost for an operator was estimated to be $49,000 per year.

Table 3 and Table 4 show a summary of the sizes and costs.

23

Table 3: Equipment Sizes and Costs for the DGAASS Process

Table 4: Operating Cost for D'GAASS Process

Operating Costs

Maintenance and Repairs $ 11,000 / year

Utility $ 39,000/ year

Labor $ 49,000/ year

Total $99,000/year

Equipment Size Installed Cost

Sulfur Degassing Vessel Height: 20 ft

Diameter: 5.2 ft

$77,000

Air Cooler 15 kW $40,000

Knockout Drum Diameter = 0.7 ft

Length = 2.3 ft

$6,000

Feed Pump 3.03 BTU/s $40,000

Compressor 15.2 BTU/s $20,000

Total : $183,000

24

8. COMPARISON OF THE TWO PROCESSES

8.1 Cost Comparison

The objective of this section is to compare the two methods and choose the best

one to recommend to Suncor. Table 5 shows a brief cost comparison of the two

methods.

Table 5: Cost Comparison between D'GAASS and Shell Processes

DGAASS Shell

Capital Costs $183,000 $705,000 Operating Costs $99,000/ year $116,000/year

The operating cost of the two processes is approximately the same. However,

there is a significant difference in capital cost. The Shell process will cost almost

four times as much as the DGAASS process.

Both processes are similar in concept. H2S concentration is reduced by contacting

sulphur with air. Furthermore, the secondary equipment, such as pumps and

heaters, are also similar. Therefore, in order to come to a final decision on which

25

process to use, a list of advantages and disadvantages for each process is

included in the sections below.

8.2 Advantages and Disadvantages for DGAASS Process

Advantages

Since Suncor is operating a similar DGAASS process in another part of

their plant; therefore, they would be familiar with the operation methods.

Furthermore, they would have experience in troubleshooting if anything

goes wrong. Moreover, the process is external of the sulphur pit so

minimum downtime will be required for installation. The vessel is only

5.2 ft in diameter and 30 ft in height which would not be an issue with

Suncors limited plot space. Finally, since the vent gas stream that contains

the H2S is sent back to the sulphur recovery unit, there will be no sulphur

emissions to the environment.

Disadvantages

Tying in a new process within an existing plot can be very difficult for

construction. It is usually easier to build something from scratch rather

than retrofit an existing plant. Some of the other equipment around within

close proximity might require some downtime. Finally, since the

26

DGAASS process is relatively new compared to the Shell process, there

may be issues that were not discovered yet.

8.2 Advantages and Disadvantages for Shell process

Advantages

The shell process does not require any extra plot space since the process

takes place within the existing sulphur pit. This is older process than the

DGAASS process so it may be easier to find solutions to potential

problems. Also, it is a simple process that requires no moving parts or

high pressures to operate.

Disadvantages

Since the system takes place in the pit, it will require more downtime to

install. It will also require downtime for maintenance if any issues arise.

Also, the pit is relatively small so the surge capacity only allows for

approximately 4 hours of downtime for maintenance when ideally 8-12

hours would be preferred. Also, it requires a higher flow rate of air than

the DGAASS process.

27

8.3 Final Decision

CHEETAH Consulting has concluded that the DGAAS process should be the

chosen option and will be recommending for Suncor to install it. The decision

was made based on lower capital cost, convenience of operation, and familiarity

to Suncor.

28

9. ECONOMICS OF DGAASS

9.1 Introduction to the Economics

The economic comparison for this project is based on the difference between the

selling price of degassed liquid sulphur and liquid sulphur that has not been

degassed. The difference between the selling prices is generally $20 per tonne

which was based upon Suncors industrial experience. In 2007, the average price

of liquid sulphur was approximately $95 per tonne based on the ICIS pricing.

The annual sales of the degassed sulphur for the plant would be approximately

$26 million per year. This is approximately $4.5 million dollars more than selling

the liquid sulphur without degassing the H2S.

9.2 Revenues, Expenses, Depreciation and Taxation

A 25 year economic period for this project was examined to determine whether

or not it was economically feasible. The revenues for this project, as mentioned

earlier, were based on the difference between selling prices and resulted in net

revenues of approximately $4.5 million per year. While the total expenses each

year for the project was only $99,000 which included maintenance and repairs,

29

operating costs and labor costs. The working capital was based on Ulrichs

guidelines of 15% of the capital costs and resulted in $32,500 being placed in the

project for this purpose. A 30% depreciation rate was used, using the half in the

first year rule which is common in Canada. The closing book value after 25 years

of the project is $35, an almost complete depreciation of initial $216,000 invested

in the project. A taxation rate of 32.12% was used which was found to be the

corporate tax rate in Alberta.

9.3 Rate of Returns and Net Present Value

A 15% minimum attractive rate of return (MARR) was used for the DGAASS

process and resulted in the net present worth (NPW) to be $18.9 million. This is

very important as it is significantly higher than the initial investment of $216,000.

This is reflected by the internal rate of return (IRR) which was found to be almost

1200%. The project returns a profit in each year of production and the project is

paid back within the first year of the project. An important factor as many

companies do not wish to invest in projects that take longer than 5 years to show

a return. The discounted breakeven point was found to be approximately 1

month. This can be seen in Figure 5 while the complete economic life of the

project can be seen in Figure 6. A more detailed look at the economics can be

seen in the income statement which is found in Appendix C.

30

Figure 5: Discounted breakeven point for the sulphur degasification project.

Figure 6: The complete economic analysis over the 25 year period.

.

0.5

0.4

0.3

0.2

0.1

0

0.1

0.2

0.3

0.4

0.5

0 0.05 0.1 0.15 0.2

Accum

.Disc.

CashFlow

$Millions

Yearsi=0% i=15%

DBEP~ 1monthati=15%

1

9

19

29

39

49

59

69

0 5 10 15 20 25Accum

.Disc.

CashFlow

$Millions

Years i=0% i=15%

31

For this project, there was no loan analysis considered due to the small relative

investment into the capital cost. Also, there was no share holder equity

considered again due to the small capital cost. The capital cost could be covered

by the companys current savings for future projects.

32

10. SAFETY CONSIDERATIONS

10.1 Introduction

Every design project must have safety as the primary concern. A full safety

analysis was conducted for the DGAASS process. This was done to ensure that

any potentials safety issues can be dealt with in an effective manner as soon as

they arise. To implement the safety analysis, research was done on all chemicals

involved in the design. The only chemicals present were sulphur and H2S/H2Sx.

Furthermore, a fully hazard and operability (HAZOP) analysis was constructed.

By doing so, suggested precautions can be taken throughout the operations.

10.2 Chemicals

The main hazardous chemical in this process is H2S. This is a colorless gas that

has a strong rotten eggs odor and can be toxic if inhaled. The occupational

exposure limit and ceiling exposure limit is 10 ppm and 15 ppm respectively. If

the H2S concentration exceeds 100 ppm, ones sense of smell becomes dead and

can be fatal at concentrations past 200ppm. Furthermore, H2S gas is highly

flammable and must be kept away from any sparks or sources of ignition. It has a

33

lower explosive limit (LEL) of 4.3 % and an upper explosive limit of 46%. More

detailed information can be found in the MSDS in Appendix E.

The other chemical in the process is sulphur, which is kept in molten state at all

times. Therefore, the temperature of it is very high in order to keep it in molten

state. Proper protective equipment must be worn when around working area of

sulphur. Furthermore, the sulphur contains H2S so all precautions are similar as

stated above for H2S. The MSDS of sulphur can also be found in Appendix E.

10.3 Personal Protection Equipment

When handling, or working around sulphur or H2S, the following personal

protection measures should be used.

Safety goggles, or face shield including a respirator should be worn at all times when sulphur or H2S is around the working environment.

Rubber or PVC gloves should be worn when handling chemicals.

Full body suites or coveralls as well as safety boots should be worn.

Potentially explosive items, such as lighters, should be kept away from working environment to avoid explosions.

34

By taking these precautions, many potential accidents can be avoided, thus

resulting in a safer workplace.

10.4 HAZOP

A full HAZOP method was performed on all pieces of equipment in the

DGAASS process. The process was broken into nodes and potential deviations

were listed for each process parameter. Then, the corresponding consequences

and suggested actions to be taken to overcome the deviation were included. This

was done to ensure that all risks were under the acceptable standards. A detailed

HAZOP can be found in Appendix D.

35

11. CONCLUSIONS

After completing the design of the DGAASS process which degasses the

sulphur, several conclusions were made.

1. The DGAASS process was chosen over the shell process for various

reasons listed in the advantages section 8.2 Advantages and Disadvantages of

DGAASS Process.

2. The product sulphur meets the product specification with an H2S

concentration of 15 ppmw. Therefore, toxicity hazards and formation of

explosive mixtures can be avoided since the H2S LEL is not reached.

3. The process costs $183,000 to install and has an annual operating cost of

$99,000. The costs were approximately a quarter of the costs for the Shell

process.

4. Degassed sulphur can be sold for $20/tonne more than undegassd

sulphur. At a selling price of $115/tone, the degassed sulphur will

generate $26 M annually, which is $4.5 M more than what undegassed

sulphur would generate in revenues.

36

5. At 15% MARR, the DGAASS process resulted in the net present worth

(NPW) of $18.9 million, with an IRR of 1200% and a break-even point of 1

month.

37

12. RECOMENDATIONS

The following are recommendations that have been suggested by CHEETAH

Consulting.

1. CHEETAH Consulting recommends that the vent gas containing H2S

and SO2 leaving the knockout drum should be sent to the SRU

(Sulphur Recovery Unit) to be converted to sulphur using the Claus

process. By doing so, sulphur emissions can be avoided.

2. The cost estimations for the process were done using shortcut methods

in Ulrich. Some of the values may be outdated even after using the

suggested correction factors. Furthermore, since the plant is in Fort

McMurray, labor costs will be significantly higher than suggested.

Also, in order to install the process, some of the surrounding

equipment in the plant may require down time. This was not taken

into consideration in the economics section.

38

REFERENCES

Air Liquide, "Material Safety Data Sheet: Hydrogen Sulphide." 04 Apr 2008 12

Feb 2008

.

Evitts, R. Course Notes. ChE 453/884. University of Saskatchewan, 2007.

Evitts, R. Course Notes. ChE 325, University of Saskatchewan, 2007.

Fenderson, Steve. "Degassing Developments." Hydrocarbon Engineering 01

April 2002

Ismagilova, Z.F. "Ecology - Development of an Industrial Process for Degassing

of Liquid Sulfur." Chemistry and Technology of Fuels and Oils, Vol. 40 04

November 2004

"Material Safety Data Sheet for SulPhur 95." 12 Feb 2008

.

Perry, R.W. and Green, D.W. Perrys Chemical Engineers Handbook (7th

Edition). New York: McGraw-Hill, 1997

39

Ulrich, Gael. Chemical Engineering Process Design and Economics: A Practical

Guide. BocaRaton: CRC Press, 2004.

I

APPENDECIES

A Shell Process: Equipment Sizes and Cost Calculations

B DGAASS Process: Equipment Sizes and Cost Calculations

C DGAASS Economics

D HAZOP Analysis

E MSDS Information

II

APPENDIX A

Shell Process: Equipment Sizes and Cost Calculations

III

Using Imagilova Article to find the residence time required for effective

removal of H2S

hh

kcc

ppmcppmchk

kcc

SHSH

SH

SH

SHSH

1.932.0

)15lg()300lg(

lglg

300

1532.0

lglg

1

0

0

1

0

22

2

2

22

=

=

===

==

The Volumetric flow rate of liquid sulphur to help determine the size of the

first compartment of the sulphur pit.

hftQ

hmQ

smQ

mkgskg

Q

qQ

3

3

3

3

3.533

1.15

004195.0

1682

056.7

=

=

=

=

=

IV

Volume required for the first compartment of the sulphur pit

31

3

1

1

4800

1.93.533

ftV

hhftV

QV

==

=

Placing the weir 85 ft from the left hand edge of the sulphur pit diagram

32

31

2256

4825

ftVftV

==

These are simple volume calculations based on the dimensions of the sulphur pit.

Surge Capacity of the second compartment to allow for downtime

ht

ftt

QVt

DT

hftDT

DT

23.43.533

22563

3

2

=

=

=

Changing the GHSV to correspond to the operating temperatures

11

11

1

2

1

2

7.4115.41235.430

40

==

=

hGHSVKK

hGHSV

TT

GHSVGHSV

V

Calculating the contact volume required

Contact volume to working volume of 20%

3

3

1416

)7081(2.0

2.0

ftVftV

VV

C

C

WC

===

Calculating the required air flow rate to lower the H2S content to 15 ppm

sftq

hftq

hmq

mqh

Vq

GHSV

air

air

air

air

L

air

3

3

3

31

1

4.16

59004

8.1670

1.407.41

=

=

=

=

=

Volume of each sparging column based on the contact volume

3arg

3

arg

arg

4723

14163

ftV

ftV

VV

sp

sp

Csp

==

=

VI

Dimensions of the sparging columns based on the height and width

constraints.

ftLftft

ftL

whV

L

ftwfth

sp

145.75.4

472

5.75.4

3

arg

==

===

Installed Cost of the 3 rectangular sparging columns

For the use of Ulrichs graphs a diameter must be known therefore a theoretical

diameter was determined

mftD

ftD

DftftftftDC

theo

theo

theo

theo

37.17.13

43)5.75.71414(

===

=+++=

Using Fig. 5.44b and Fig. 5.46 of Ulrich

000,195$

)400

2.528)(2.4)(000,35($

400

2.5282.4

000,35$

2007,

2007,

2007,

==

==

==

CSBM

CSBM

aBMp

CSBM

aBM

p

C

C

tIndexCEPlantCosFCC

tIndexCEPlantCosF

C

VII

For 3 columns = $585,000

Sizing and Cost of the Product Pump to pump liquid sulphur 3000 ft and into a

50 ft high tank

Determine the size of the pipe to deliver to storage knowing that the

velocity should not exceed 3 to 6 ft/s.

2

3

037.0

4

148.0

ftAsftsft

A

vQA

pipe

pipe

pipe

=

=

=

sftvinDinD

ftD

AD

pipe

pipe

pipe

pipepipe

/02.3

3

6.24

037.0

42

===

=

=

The pressure at the bottom of the sulphur pit was determined to find the inlet

pressure to the pump

VIII

kPaPkPaP

kPamsm

mkgP

PghP

in

pit

pit

atmpit

3.101

56.146

3.10174.281.91682 23

==

+=+=

The inlet pressure is equal to atmospheric pressure due to the pressure losses

due to the height of the pit

Using the equivalent length method assuming there is only the 2 elbows.

mftLe 88.416 ==

Determining the flow regime using Reynolds number

12819008.0

0662.0921.01682

Re

3

Re

Re

=

=

=

NsPa

msm

mkg

N

DuN pipeb

At this Reynolds number the flow is turbulent.

41090.6

2.660457.0

=

=

pipe

pipe

D

mmmm

D

Using the Moody Diagram the fanning friction factor was determined to be:

0075.0=f

IX

Calculating the pressure drop across the length of the pipe using the equivalent

length method

kPaP

msm

mkgmm

kgsm

P

ghD

LufP

flow

flow

pipe

ebflow

1.547

2.1581.916820662.0

)3.919()1682()921.0(0075.02

2

23

32

2

=+

=

+=

Therefore the outlet pressure of the pump is:

kPaPkPakPaP

PPP

out

out

atmflowout

4.6483.1011.547

=+=

+=

Therefore the change in pressure for the pump is:

kPaPkPakPaP

PPP

pump

pump

inoutpump

1.5473.1014.648

==

=

Ulrichs recommendations require the intrinsic efficiency.

464.0))008.0(1)()1020.4(12.01(

)1)(12.01(8.027.03

8.027.0

==

=

i

i

i q

X

From this the shaft work for the pump was determined.

sBTUkWW

kPasm

W

PqW

s

s

i

pumps

69.495.4

464.0

)1.547(102.43

3

==

=

=

Based on the operating conditions a centrifugal radial pump was selected and

the cost estimated using Fig. 5.49 of Ulrich.

000,41$400

2.528)900,8($5.3

5.3

0.10.1

900,8$

2007,

2007,

==

====

CSBM

CSBM

aBM

p

m

p

C

C

F

FFC

Sizing and Cost of the Main Air Blower

Determining the volumetric flow rate of air at the inlet of the blower

hmq

mkgmkg

hm

q

qq

airin

airin

airin

airout

airout

airin

3

3

3

3

5.1188

2.1

854.0

1670

=

=

=

XI

Assuming that the air is an ideal gas and the efficiency of the blower is on the

low end of the range at 65%.

sBTUkWW

molkg

KKmol

Jskg

W

PP

CTRZqW

CC

ZKmol

JC

KmolJC

s

s

pi

airinairins

V

p

V

p

92.63.7

)1)148.1(()40.040.1(

029.0

15.289314.8

65.0

396.0

)1)((1

40.1

1

831.20

145.29

40.140.0

1

1

2

==

=

=

===

==

Using Fig. 5.30 of Ulrich to estimate the cost of the blower

kWWWW

f

Sif

8.4==

Therefore the Blower and the drive system will cost:

000,51$

)400

2.528)(800$5.1000,15$5.2(

)400

2.528()(

5.15.2

800$

.000,15$

2007,

2007,

,,,,2007,

,

,

,

,

=+=

+===

==

CSBM

CSBM

DrivepDriveBMBlowerpBlowerBMCSBM

DriveBM

BlowerBM

Drivep

Blowerp

C

C

CFCFC

FFCC

XII

Sizing and Cost of the Heat Exchanger

Using a counter-current shell and tube heat exchanger with steam as the heating

agent.

kWQ

CCKkg

kJskgQ

TCmQ pair

6.52

)252.157(005.1396.0

=

==

From Table 4-15a of Ulrichs

KsmJU

PU

==

2

5.0

100

100

To calculate the surface area of the heat exchanger

LMTFUAQ =

KT

CCT

TTTTT

LM

LM

LM

4.74

)9.261.159ln(

9.261.159

)ln(1

2

12

=

==

Using Fig. 4.22a of Ulrichs to determine the value of F

0.1=F

XIII

Therefore:

22

2

1.7607.7

4.74)100(16.52

ftmA

AKKm

WkW

===

The cost of this unit was found using Fig.36 of Ulrich

000,14$

)400

2.528(0.3)500,3($

500,3$0.3

0.10.1

2007,

2007,

==

==

==

CSBM

CSBM

p

BM

P

M

C

C

CFFF

XIV

APPENDIX B

DGAASS Process: Equipment Sizes and Cost Calculations

XV

Please note that all calculations were used following the method proposed in the

Chemical Engineering Process Design and Economics by Ulrich. Therefore, in order

to follow the suggested calculations, all the data was converted to SI units and

finally converted back to imperial units.

Feed inlet pump

We want to produce an outlet flow rate of 600 long tonnes per day. Therefore

changing the units into SI, we get the following:

(600 day

tonnes )(1016.047 tonnekg )(

hoursday

241 )(

shr

36001 ) = 7.06 kg/s

Assume an inlet flow rate of 2.0 kg/s

Assumed the operating pressure was larger than 30 psi.

The next step was the conversion of the inlet and outlet flow rate to L/min. In

order to do this we had to figure out the density of molten sulphur at 157 o C

(this temperature was the associated temperature in regards to the inlet side of

the pump). After consulting the GPSA Handbook, the density of this

corresponding sulphur at that particular temperature was 1500 kg/m3

Flow rate at inlet: FINLET= 80 L/min

Flow rate at outlet: FOUTLET= 282 L/min.

XVI

Since the molten sulphur that was being pumped did not contain any particulate

matter, it was decided that this pump was a centrifugal pump.

In order to calculate the shaft power, the following formula was used:

kWbarPaxbar

EpqW

mkg

skg

s 2.3)65.0)(704()/101)(068.2)(056.7(

3

5

=== = 3.03 BTU/s

Note: the above the efficiency value was assumed at 65%.

This pump was made from carbon steel.

At this point, the capital cost could be determined by means of figures 5.50 and

5.51 on the following page from the Chemical Engineering: Process Design and

Economics a Practical Guide:

XVII

XVIII

Thus, using the main formula to calculate the installed cost:

CBM=CPxFBM

CBM=($10000)(3)

CBM=$30000

This price was the purchasing installed price for the year 2004. Thus, an

appropriate adjustment had to be made in order to predict the value for 2008.

Therefore, the calculated installed cost was multiplied by1.32 (inflation rate and

the time value of money) and was found to be approximately

Shaft Power: 3.03 BTU/s

Price: $40000.

XIX

Knock Out Drum

Using the main formula to calculate diameter of the knock out drum:

))()(())()(4(

tgas

gas

UMWV

D =

Where

sm

mkg

mkg

mkg

g

gltU 184.402.1

02.16.17861.0

)(1.0

21

3321

=

==

V = (Gas flow rate)(Density of gas)(1/MWgas)

V = s

kgmolemkg

sm

kgmolekg 00307.0)29

1)(02.1)(0874.0( 33

=

Thus,

inchmDsm

mkg

kgmolekg

skgmole

4.61829.0)184.4)(02.1(

)29)(00307.0)(4( 21

3

==

=

Using shortcut method, the length would simply be L x 4.Therefore,

L = 6.4 in x 4 = 25.6 in = 2.13 ft

XX

The cost index of this knockout drum was calculated by the same technique as

shown above for the inlet feed pump and a value of $6000 was determined from

page 390 in Chemical Engineering: Process Design and Economics a Practical

Guide.

Diameter: 6.4 in

Length: 2.13 ft

Price: $6,000

XXI

Air Cooler

This air cooler was a simple fin fan air cooler.

Referring to page 201 and table 4.13 in the Chemical Engineering: Process

Design and Economics a Practical Guide, it clearly stated that for a horizontal

air cooler the standard power consumption ranged from 0.1 to 0.15 kW/m2.

Size = ))(( areapower

The area was assumed to be 100 m2. Therefore

Size = (0.15 kW/m2)( 100 m2)

Size = 15 kW = 14.2 BTU/s

Referring to figure 5.40 in the Chemical Engineering: Process Design and

Economics a Practical Guide, the approximate installed price of the air cooler

was approximately $40000.

Size: 14.2 BTU/s

Price: $40,000

XXII

Sulphur Degassing Unit (Contact Column/Vessel)

Used an air to sulphur ratio of 0.2 standard cubic feet per pound of liquid molten

sulphur. (Suncors recommendation).Using the following formula to calculate the

diameter:

= ))((

))()(4(

,gsg

g

UMWV

D

Where: V = 0.0874 m3/s x 1 kmol/29 kg = 3.07 mol/s

smg

glgsU 76.302.1

02.1178609.009.0, =

=

=

ftmD 2.564.1)76.3)(02.1)((

)29)(07.3)(4( ==

=

Using the shortcut method, the height of the column was simply found by:

Ht=0.5D0.3=20 ft.

Referring to pages 387 and 388 in the Chemical Engineering: Process Design

and Economics a Practical Guide, the capital cost of the contact column was

approximately $77000.

Diameter: 5.2 ft

Height: 20 ft

Cost: $77,000

XXIII

Compressor

By following pages 157 and 158 in the Chemical Engineering: Process Design

and Economics a Practical Guide, the corresponding size and cost of the

compressor could be readily found.

Using the main formula to calculate the size:

=

1)1(

))()()()((1

1

2nn

PP

nnTRzmW

is

Where: m = 0.10488 kg/s

Z = 1 R = 0.0832 L.atm K-1mol-1

T = 298.15 K n = 1.237

P2 = 2.918 P1 = 1

Therefore, substituting all the values into the above equation yields:

Ws = 16.1 kW = 15.2 BTU/s

Referring to page 380 in Chemical Engineering: Process Design and Economics

a Practical Guide the approximate capital cost was $20000

Power: 15.2 BTU/s

Price: $20,000

XXIV

APPENDIX C

DGAASS Economics

XXV

Table 4: Cash Flow Analysis for DGAASS Process

Period 0 1 2 3 4 5 6 7 8

Operating Activities Net Income $2,931,534 $2,916,138 $2,927,355 $2,935,206 $2,940,702 $2,944,550 $2,947,243 $2,949,128 Non-Cash Expenses $32,400 $55,080 $38,556 $26,989 $18,892 $13,225 $9,257 $6,480 Total $2,963,934 $2,971,218 $2,965,911 $2,962,196 $2,959,595 $2,957,774 $2,956,500 $2,955,608 Investing Activities Fixed Asset (Acquisitions) -$216,000 $0 $0 $0 $0 $0 $0 $0 $0 Fixed Asset Disposal Proceeds $0 $0 $0 $0 $0 $0 $0 $0 $0 Working Capital (Increase)/Decrease -$32,500 $0 $0 $0 $0 $0 $0 $0 $0 Disposal Tax Effects $0 $0 $0 $0 $0 $0 $0 $0 Total -$248,500 $0 $0 $0 $0 $0 $0 $0 $0 Financing Activities Borrowings $0 Principal Re-payments $0 $0 $0 $0 $0 $0 $0 $0 Shareholder Investment $0 $0 $0 $0 $0 $0 $0 $0 $0 Dividends to Shareholders $0 $0 $0 $0 $0 $0 $0 $0 $0 Total $0 $0 $0 $0 $0 $0 $0 $0 $0 Net Cash Flow -$248,500 $2,963,934 $2,971,218 $2,965,911 $2,962,196 $2,959,595 $2,957,774 $2,956,500 $2,955,608 MARR 15.00% IRR 1192.94% Net Present Worth $18,886,773

XXVI

Table 6 Continued

Period 9 10 11 12 13 14 15 16 17 Operating Activities Net Income $2,950,448 $2,951,371 $2,952,018 $2,952,471 $2,952,787 $2,953,009 $2,953,164 $2,953,273 $2,953,349 Non-Cash Expenses $4,536 $3,175 $2,223 $1,556 $1,089 $762 $534 $374 $261 Total $2,954,984 $2,954,547 $2,954,241 $2,954,026 $2,953,877 $2,953,772 $2,953,698 $2,953,647 $2,953,611 Investing Activities Fixed Asset (Acquisitions) $0 $0 $0 $0 $0 $0 $0 $0 $0 Fixed Asset Disposal Proceeds $0 $0 $0 $0 $0 $0 $0 $0 $0 Working Capital (Increase)/Decrease $0 $0 $0 $0 $0 $0 $0 $0 $0 Disposal Tax Effects $0 $0 $0 $0 $0 $0 $0 $0 $0 Total $0 $0 $0 $0 $0 $0 $0 $0 $0 Financing Activities Borrowings Principal Re-payments $0 $0 $0 $0 $0 $0 $0 $0 $0 Shareholder Investment $0 $0 $0 $0 $0 $0 $0 $0 $0 Dividends to Shareholders $0 $0 $0 $0 $0 $0 $0 $0 $0 Total $0 $0 $0 $0 $0 $0 $0 $0 $0 Net Cash Flow $2,954,984 $2,954,547 $2,954,241 $2,954,026 $2,953,877 $2,953,772 $2,953,698 $2,953,647 $2,953,611 MARR Net Present Worth

XXVII

Table 6 Continued

Period 18 19 20 21 22 23 24 25 Operating Activities Net Income $2,953,402 $2,953,440 $2,953,466 $2,953,484 $2,953,497 $2,953,506 $2,953,512 $2,953,516 Non-Cash Expenses $183 $128 $90 $63 $44 $31 $22 $15 Total $2,953,585 $2,953,568 $2,953,555 $2,953,547 $2,953,541 $2,953,537 $2,953,534 $2,953,532 Investing Activities Fixed Asset (Acquisitions) $0 $0 $0 $0 $0 $0 $0 $0 Fixed Asset Disposal Proceeds $0 $0 $0 $0 $0 $0 $0 $0 Working Capital (Increase)/Decrease $0 $0 $0 $0 $0 $0 $0 $0 Disposal Tax Effects $0 $0 $0 $0 $0 $0 $0 $0 Total $0 $0 $0 $0 $0 $0 $0 $0 Financing Activities Borrowings Principal Re-payments $0 $0 $0 $0 $0 $0 $0 $0 Shareholder Investment $0 $0 $0 $0 $0 $0 $0 $0 Dividends to Shareholders $0 $0 $0 $0 $0 $0 $0 $0 Total $0 $0 $0 $0 $0 $0 $0 $0 Net Cash Flow $2,953,585 $2,953,568 $2,953,555 $2,953,547 $2,953,541 $2,953,537 $2,953,534 $2,953,532 MARR Net Present Worth

XXVIII

Table 5: Income Statement for DGAASS Process

Period 1 2 3 4 5 6 7 8 Revenue Sulphur Sales $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 Total Revenue $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 Expenses Maintenance/Repairs $11,000 $11,000 $11,000 $11,000 $11,000 $11,000 $11,000 $11,000Labour $49,000 $49,000 $49,000 $49,000 $49,000 $49,000 $49,000 $49,000Utility $38,900 $38,900 $38,900 $38,900 $38,900 $38,900 $38,900 $38,900 Depreciation $32,400 $55,080 $38,556 $26,989 $18,892 $13,225 $9,257 $6,480 Interest $0 $0 $0 $0 $0 $0 $0 $0Total Expenses $131,300 $153,980 $137,456 $125,889 $117,792 $112,125 $108,157 $105,380 Taxable Income Rate $4,318,700 $4,296,020 $4,312,544 $4,324,111 $4,332,208 $4,337,875 $4,341,843 $4,344,620 Income Taxes 32.12% $1,387,166 $1,379,882 $1,385,189 $1,388,904 $1,391,505 $1,393,326 $1,394,600 $1,395,492Net Income $2,931,534 $2,916,138 $2,927,355 $2,935,206 $2,940,702 $2,944,550 $2,947,243 $2,949,128

XXIX

Table 7 continued

Period 9 10 11 12 13 14 15 16 Revenue Sulphur Sales $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 Total Revenue $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 Expenses Maintenance/Repairs $11,000 $11,000 $11,000 $11,000 $11,000 $11,000 $11,000 $11,000Labour $49,000 $49,000 $49,000 $49,000 $49,000 $49,000 $49,000 $49,000Utility $38,900 $38,900 $38,900 $38,900 $38,900 $38,900 $38,900 $38,900 Depreciation $4,536 $3,175 $2,223 $1,556 $1,089 $762 $534 $374 Interest $0 $0 $0 $0 $0 $0 $0 $0Total Expenses $103,436 $102,075 $101,123 $100,456 $99,989 $99,662 $99,434 $99,274 Taxable Income Rate $4,346,564 $4,347,925 $4,348,877 $4,349,544 $4,350,011 $4,350,338 $4,350,566 $4,350,726 Income Taxes 32.12% $1,396,116 $1,396,553 $1,396,859 $1,397,074 $1,397,223 $1,397,328 $1,397,402 $1,397,453Net Income $2,950,448 $2,951,371 $2,952,018 $2,952,471 $2,952,787 $2,953,009 $2,953,164 $2,953,273

XXX

Table 7 continued

Period 17 18 19 20 21 22 23 24 25 Revenue Sulphur Sales $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 Total Revenue $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 $4,450,000 Expenses Maintenance/Repairs $11,000 $11,000 $11,000 $11,000 $11,000 $11,000 $11,000 $11,000 $11,000Labour $49,000 $49,000 $49,000 $49,000 $49,000 $49,000 $49,000 $49,000 $49,000Utility $38,900 $38,900 $38,900 $38,900 $38,900 $38,900 $38,900 $38,900 $38,900 Depreciation $261 $183 $128 $90 $63 $44 $31 $22 $15 Interest $0 $0 $0 $0 $0 $0 $0 $0 $0Total Expenses $99,161 $99,083 $99,028 $98,990 $98,963 $98,944 $98,931 $98,922 $98,915 Taxable Income Rate $4,350,839 $4,350,917 $4,350,972 $4,351,010 $4,351,037 $4,351,056 $4,351,069 $4,351,078 $4,351,085 Income Taxes 32.12% $1,397,489 $1,397,515 $1,397,532 $1,397,545 $1,397,553 $1,397,559 $1,397,563 $1,397,566 $1,397,568Net Income $2,953,349 $2,953,402 $2,953,440 $2,953,466 $2,953,484 $2,953,497 $2,953,506 $2,953,512 $2,953,516

XXXI

Table 6: Depreciation Effects for DGAASS Process

Period 0 1 2 3 4 5 6 7 8 9 Total Depreciation Expense

$32,400 $55,080 $38,556 $26,989 $18,892 $13,225 $9,257 $6,480 $4,536

Total Asset Acquisitions -$216,000 $0 $0 $0 $0 $0 $0 $0 $0 $0 Declining Balance Method Asset 1 0 1 2 3 4 5 6 7 8 9Capital Cost Allowance 30.00% Percent in First Year 50.00% Acquisition Cost (-$"s) at t=n

-$216,000

Opening Book Value $216,000 $183,600 $128,520 $89,964 $62,975 $44,082 $30,858 $21,600 $15,120Depreciation Expense $32,400 $55,080 $38,556 $26,989 $18,892 $13,225 $9,257 $6,480 $4,536Closing Book Value $183,600 $128,520 $89,964 $62,975 $44,082 $30,858 $21,600 $15,120 $10,584

Table 8 Continued

Period 10 11 12 13 14 15 16 17 18 19 Total Depreciation Expense $3,175 $2,223 $1,556 $1,089 $762 $534 $374 $261 $183 $128Total Asset Acquisitions $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 Declining Balance Method Asset 1 10 11 12 13 14 15 16 17 18 19Capital Cost Allowance Percent in First Year Acquisition Cost (-$"s) at t=n Opening Book Value $10,584 $7,409 $5,186 $3,630 $2,541 $1,779 $1,245 $872 $610 $427Depreciation Expense $3,175 $2,223 $1,556 $1,089 $762 $534 $374 $261 $183 $128Closing Book Value $7,409 $5,186 $3,630 $2,541 $1,779 $1,245 $872 $610 $427 $299

XXXII

Table 8 Continued

Period 20 21 22 23 24 25 Total Depreciation Expense $90 $63 $44 $31 $22 $15 Total Asset Acquisitions $0 $0 $0 $0 $0 $0 Declining Balance Method Asset 1 20 21 22 23 24 25 Capital Cost Allowance Percent in First Year Acquisition Cost (-$"s) at t=n Opening Book Value $299 $209 $146 $103 $72 $50 Depreciation Expense $90 $63 $44 $31 $22 $15 Closing Book Value $209 $146 $103 $72 $50 $35

XXXIII

Table 7: Discounted Break Even Point for DGAASS Process

Year AI AS ATE AD AIT ANCI .+ANCI fd ADCF .+ADCF 0 -248500 1 -$248,500 $4,450,000 $98,900 $32,400 $1,387,166 $2,715,434 $2,715,434 0.870 $2,361,247 $2,361,247 2 $0 $4,450,000 $98,900 $55,080 $1,379,882 $2,971,218 $5,686,652 0.756 $2,246,668 $4,607,915 3 $0 $4,450,000 $98,900 $38,556 $1,385,189 $2,965,911 $8,652,563 0.658 $1,950,135 $6,558,049 4 $0 $4,450,000 $98,900 $26,989 $1,388,904 $2,962,196 $11,614,759 0.572 $1,693,645 $8,251,694 5 $0 $4,450,000 $98,900 $18,892 $1,391,505 $2,959,595 $14,574,354 0.497 $1,471,442 $9,723,136 6 $0 $4,450,000 $98,900 $13,225 $1,393,326 $2,957,774 $17,532,128 0.432 $1,278,727 $11,001,864 7 $0 $4,450,000 $98,900 $9,257 $1,394,600 $2,956,500 $20,488,628 0.376 $1,111,458 $12,113,321 8 $0 $4,450,000 $98,900 $6,480 $1,395,492 $2,955,608 $23,444,236 0.327 $966,193 $13,079,515 9 $0 $4,450,000 $98,900 $4,536 $1,396,116 $2,954,984 $26,399,220 0.284 $839,991 $13,919,506 10 $0 $4,450,000 $98,900 $3,175 $1,396,553 $2,954,547 $29,353,767 0.247 $730,319 $14,649,825 11 $0 $4,450,000 $98,900 $2,223 $1,396,859 $2,954,241 $32,308,008 0.215 $634,994 $15,284,819 12 $0 $4,450,000 $98,900 $1,556 $1,397,074 $2,954,026 $35,262,034 0.187 $552,129 $15,836,947 13 $0 $4,450,000 $98,900 $1,089 $1,397,223 $2,953,877 $38,215,911 0.163 $480,088 $16,317,035 14 $0 $4,450,000 $98,900 $762 $1,397,328 $2,953,772 $41,169,683 0.141 $417,453 $16,734,487 15 $0 $4,450,000 $98,900 $534 $1,397,402 $2,953,698 $44,123,381 0.123 $362,993 $17,097,481 16 $0 $4,450,000 $98,900 $374 $1,397,453 $2,953,647 $47,077,028 0.107 $315,641 $17,413,121 17 $0 $4,450,000 $98,900 $261 $1,397,489 $2,953,611 $50,030,639 0.093 $274,467 $17,687,588 18 $0 $4,450,000 $98,900 $183 $1,397,515 $2,953,585 $52,984,224 0.081 $238,665 $17,926,253 19 $0 $4,450,000 $98,900 $128 $1,397,532 $2,953,568 $55,937,792 0.070 $207,533 $18,133,787 20 $0 $4,450,000 $98,900 $90 $1,397,545 $2,953,555 $58,891,347 0.061 $180,463 $18,314,250 21 $0 $4,450,000 $98,900 $63 $1,397,553 $2,953,547 $61,844,894 0.053 $156,924 $18,471,174 22 $0 $4,450,000 $98,900 $44 $1,397,559 $2,953,541 $64,798,435 0.046 $136,455 $18,607,629 23 $0 $4,450,000 $98,900 $31 $1,397,563 $2,953,537 $67,751,972 0.040 $118,657 $18,726,286 24 $0 $4,450,000 $98,900 $22 $1,397,566 $2,953,534 $70,705,506 0.035 $103,180 $18,829,465 25 $0 $4,450,000 $98,900 $15 $1,397,568 $2,953,532 $73,659,038 0.030 $89,721 $18,919,186

XXXIV

APPENDIX D

HAZOP ANALYSIS

XXXV

Company: CHEETAH Consulting

Sulphur Degassing

Section: D'GAASS Process

Study Node Process

Parameter Guide Word Possible Causes

Possible Consequences Safeguards

Contact Vessel

Sulphur Flow Rate

Less Pump

Malfunction Excess Air regular maintenance of pump

Less

Solid Sulphur plugging pipeline

improper separation clean pipeline

more Pump

Malfunction

Higher concentrations of

hydrogen sulphide being emitted to atmosphere from

vent gas regular maintenance of pump

no Pump failure

pure air in column: improper

separation regular maintenance of pump

Air Flow Rate

Less Compressor Malfunction

Excess sulphur and higher hydrogen

sulphide concentrations regular maintenance of compressor

Table 10: Hazop Analysis

XXXVI

More

Compressor Malfunction Excess air regular maintenance of compressor

no Compressor Malfunction

Pure sulphur and hydrogen sulphide

in vessel new compressor

Pressure

high Pump

Malfunction Operation under

high pressure regular maintenance of pump

high Compressor Malfunction

Operation under high pressure regular maintenance of compressor

Temperature

high Cooler

Malfunction

Not at optimal operating

temperature. Improper

separation regular maintenance of cooler

high

sulphur in the pit not at desired/regul

ar temperature

Not at optimal operating

temperature. Improper

separation

Installation of a temperature indicator controller in sulphur pit

Pump

Flow Rate

high

Sulphur recovery unit operating at higher than expected capacity Damage to pump

Installation of a flow indicator controller to maintain the flow rate

Low No suction Damage to pump regular maintenance of pump

XXXVII

Pressure

high Pump

Malfunction Damage to pump regular maintenance of pump

Low No suction Damage to pump regular maintenance of pump

Cooler

Temperature

High Not enough air supply

Not achieving optimal separation

temperature installation of a temperature indicator

controller

Low Too much air supply

Not achieving optimal separation

temperature installation of a temperature indicator

controller

Compressor

Flow Rate

High Compressor Malfunction

Improper compression installation of an air flow indicator

Low Compressor Malfunction

Improper compression installation of an air flow indicator

Temperature

High Compressor Malfunction

Improper Compression

installation of a temperature indicator controller

XXXVIII

Low Compressor Malfunction

Improper Compression

installation of a temperature indicator controller

Pressure

High compressor Malfunction

Excess compression installation of a pressure controller

High compressor Malfunction

compressor damage regular compressor maintenance

Low compressor Malfunction

compressor damage regular compressor maintenance

Low compressor Malfunction

Insufficient compression installation of a pressure controller

XXXIX

APPENDIX E

MSDS Information

XL

SULPHURSection I - General Information - Return To Top Of Page

Trade Name: Sulfur 95

End Use: Dispersible Sulphur Fertilizer

Appearance: Taupe (Beige) Granular Solid

Manufacturer: Agrimax Ltd. Box 9 Irricana, Alberta, Canada T0M 1B0 Tel: (403) 935 - 8800 Fax: (403) 935 - 4123

Section II - Ingredients/Hazard - Information - Return To Top Of Page

ITEMS CAS NO PERCENT OSHA PEL ACGIH TLV

Sulphur 7704-34-9 95 15MG/M3

IOMG/M3

Contains no Sara Title III, Section 313 notification chemicals or above the Deminmus Concentration. Ingredients not precisely identified are non hazardous.

WARNING: Sulphur dust suspended in air ignites easily emitting asphyxiating fumes. Excessive dust can result in an explosion in confined areas. Must keep sulphur away from heat sources, sparks, flames, friction, oxidizing materials, and static electricity. Avoid contact with eyes.

Section III - Product Description - Return To Top Of Page

Appearance: Granular Solid

Colour: Taupe (Beige)

Odor: Sulphur Odor

Boiling Point: 832o F (444O C)

Melting Point: 222oF (113-119oC)

Vapour Pressure: 0.105 mmHg AT 284oF (140.2oC)

XLI

Vapour Density: >1

Solubility in Water: Insoluble

PH - Dry: Neutral

Bulk Density: 56 - 60 lbs/ft3

Section IV - Fire And Explosion Information - Return To Top Of Page

Flash Point: 405 o F (207.2 o C)

Flammable Limits (g/m3 in Air):

Lower Explosion Limit: 53 Higher Explosion Limit: 460

Auto Ignition Temp: 470 - 511 o F (248 - 266 o C)

The primary hazard is that the dust suspended in air ignites easily and can result in explosion in confined areas, ignition can be caused by hear sources, friction, oxidizing materials, and static electricity.

Fire Fighting: Burning sulphur converts to sulphur dioxide. Fire should be approached and fought from up wind position.

Fire Fighting Media: Water Fog Spray***, Sand or Carbon Dioxide.

Note: *** Solid stream of water must never be used because of the possibility of dispersing dust clouds which could potentially cause an explosion. Fire will rekindle until mass is cooled below 310oF (154oC). To prevent re-ignition surrounding area must also be cooled with water mist as well.

Section V - Reactivity Data - Return To Top Of Page

Stability: Stable at ambient temperature and atmospheric pressure.

Materials to Avoid: Oxidizing agents, alkaline copper and copper alloys. Damp material will corrode steel.

Conditions to Avoid: Keep away from all heat sources, sparks, open flame, friction, oxidizing materials, and static electricity. Sulphur dust can be potentially explosive if more than 53 g/m3 in air.

Hazardous Decomposition:

Sulphur dioxide is generated upon material combustion.

Hazardous Polymerization:

N/A.

Section VI - Health Hazard Information - Return To Top Of Page

XLII

Inhalation: Prolonged exposure may aggravate acute asthma and other chronic pulmonary diseases.

Ingestion: Not likely to occur. In solid form, non-toxic through ingestion.

Skin Contact: Prolonged contact may cause light skin irritation. Perspiration or moisture may aggravate this in sensitive individuals.

Eye Contact: Is an eye irritant.

Toxicity: N/A.

Carcinogenicity Teratogencity Mutagenicity:

This product does not contain any ingredient designated by NTP, IARC OR OSHA as a human carcinogen.

Section VII - Preventative Measures - Return To Top Of Page

Personal Protection Equipments:

Goggles, gloves, dusk mask.

Engineering Controls: Provide adequate ventilation to maintain airborne dust concentration below applicable occupational exposure limits.

Storage & Handling: Avoid generation and accumulation of dust. Keep away from all sources of ignition.

Leak & Spill Handling:

Eliminate all sources of ignition. Collect spilled material and dispose of in compliance with all applicable federal, provincial and municipal regulations.

Transportation Requirements:

US & Canadian shipments: non regulated as per T.D.G.A.R.'s exemption part 2.3(a) (XXXIII) and 49 CFR (Canadian shipments and packaging 171.12 (a)) and CFR49 (Special Provisions 172.102 PT 30) International Shipments: Air (IATA) exempted under special provisions A105 SEA (IMDG) - exempted as per Section II Proper Shipping name: Sulphur Pin # UN1350, Packing Group - CLASS III, PRIMARY CLASS - 4.1 WHMIS - non-controlled product in accordance with Sub-Paragraph 13(A) (I - IV) or paragraph 14 (A) of the Hazardous Product Storage Act.

Section VIII - Emergency First Aid Procedure - Return To Top Of Page

Eye Contact: Flush eyes with water for 15 minutes. If irritation persists seek medical attention.

Dust Inhalation: Move to fresh air. If necessary seek medical attention.

Skin Contact: Wash thoroughly with soap and water.

XLIII

Ingestion: Not likely to occur.

Section IX - Preparation Of MSDS - Return To Top Of Page

PREPARED BY: R&D DEPARTMENT, SulFer Works PHONE: (403) 935-8800 DATE: NOVEMBER 1, 2000.

Information presented in this MSDS has been compiled from sources considered to be dependable, and is accurate and reliable to the best of our knowledge and belief, but is not guaranteed to be so. Since conditions of use are beyond our control, we make no warranties, expressed or implied. If this document is reproduced it should be done so in its entirety

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H2S

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