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Group L - Final Report
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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.
19
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
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
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
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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
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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
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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
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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)
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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
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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.
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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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