United States Industrial Environmental Research Laboratory EPA-600/8-80-002
Environmental Research Triangle Park NC 27711 January, 1980
Protection Agency
Research and Development
SASOL: South Africa's
Oil from Coal Story --
Background for
Environmental Assessment
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EPA-600/8-80-002
JANUARY 1980
SASOL:
SOUTH AFRICA'S OIL FROM COAL STORY
- BACKGROUND FOR
ENVIRONMENTAL ASSESSMENT
By
J. L. Anastai
TRW, Inc
One Space Park
Radondo Beach, California 90278
Contract No. 68-02-2635
EPA Project Officer: William J. Rhodes
Industrial Environmental Research Laboratory
Office of Environmental Engineering and Technology
Research Triangle Park. N.C. 27711
Prepared for
U. S. Environmental Protection Agency
Office of Research and Development
Washington, D.C. 20460
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ABSTRACT
The report describes the world's only oil-from-coal plant, known as
SASOL, operated by South Africa since 1955. When almost $7 billion worth
of expansion is completed in the early 1980's, three SASOL plants will
produce a total of 112,000 barrels of oil per day, or about half of South
Africa's needs. Production costs average $17 per barrel, well below the
1979 OPEC price of more than $20 per barrel.
South African motorists pay about $2.40/gallon ($0.63/liter) of gaso-
line at the pump. SASOL converts coal to liquid fuels in two steps: (1)
the coal is gasified with oxygen and steam under pressure to yield a mix-
ture of reactive gases, and (2) after being cleaned of impurities, the
mixture is passed over an iron-based catalyst in Fischer-Tropsch synthesis
units to produce liquid fuels. SASOL's operation is helped by South Africa's
abundance of cheap labor and low cost coal.
The U.S., like South Africa, has vast coal reserves. Although com-
parisons are difficult, it has been estimated that oil could not be produced
from coal in the U.S. for less than $27 per barrel and perhaps as much as
$45. The South African system is the only commercially proven process for
the production of synthetic liquid fuels. The report provides some of the
background on a process that will receive high priority for environmental
assessment.
ii
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CONTENTS
Page
Abstract ii
1. Introduction 1
2. Historical Background 4
3. Sasol I, Sasol II, Sasol III 7
4. Detailed Description of the Process 10
4.1 Sasol I 10
4.2 Sasol II and Sasol III 25
5. Conclusions 32
6. References 34
List of Figures
1. South Africa's Sasol Process 2
2. Block Diagram of Sasol I Process 11
3. Fixed Bed Arge Reactor 21
4. Fluid Bed Synthol Reactor - 23
List of Tables
1. Typical Analysis of Sasol Coal 12
2. Typical Composition of Raw and Pure Synthesis Gas 17
3. Comparison of Fixed Bed and Fluid Bed Conditions and Products . 19
4. Sasol Products and Intermediates 26
iii
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1. Introduction
Since 1955, South Africa has operated the only oll-from-coal plant
1n the world. The plant 1s known as Sasol, an acronym for South African
Coal. 011, and Gas Corporation. When almost $7 billion of expansion Is
completed 1n the early 1980's, three Sasol plants will produce a total of
112,000 barrels of oil a day or about half of South Africa's needs. Pro-
duction costs amount to $17 per barrel, well below the OPEC price of around
$20 per barrel and much less than the $31 per barrel that South Africa has
to pay on the spot market. South African motorists pay about $2.40 per
gallon of gasoline (63^/11ter) at the pump.
Sasol converts coal to liquid fuels In two steps (Figure 1). First,
the coal 1s burned with oxygen and steam under pressure to yield a gaseous
mixture which 1s principally hydrogen, carbon monoxide, and methane. This
gas 1s cleaned of Impurities using processes that produce valuable chemi-
cal by-products. Once this Is completed, the gas 1s passed over an Iron-
based catalyst 1n the second step to produce liquid fuels. Sasol produces
a full range of hydrocarbons Including fuel gas, liquefied petroleum gas
(LPG), gasoline, dlesel oil, parafln waxes, and chemicals such as alcohol
and acetone. The yield of products obtained can be altered by changing
such variables as the temperature, pressure, catalyst, or feed gas com-
position.
Even though Sasol's operation 1s helped by South Africa's abundance
of cheap labor and low cost coal, Sasol's success Indicates that producing
synthetic fuels from coal 1s one solution to meeting the energy needs of
a country without depending on natural gas or crude oil.
The United States, like South Africa, has vast coal reserves and
decreasing reserves of natural gas and crude oil. The current world-wide
energy crisis has revealed the vulnerability of the United States' oil
and natural gas supplies to uncontrolled events 1n other parts of the
world. Therefore coal must by necessity play an ever widening role 1n
America's energy future. The abundance of oil and natural gas In the
past has determined the energy forms Americans are accustomed to using.
1
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CONVERTING COAL INTO SYNTHETIC FUELS
(Tars, particulates, sulfur compounds,
and carbon dioxide removed)
350-550
pounds pressure
per square inch
(24OO-3800 kPa)
Gas
Catalyst
(iron oxide —rust)
Steam J
330-360
pounds pressure
per square inch
(2300-2BOO kPa)
Oxygen
(Allows controlled
combustion for heat)
(Supplies hydrogen from water)
Ash
(Hydrogen,
carbon monoxide,
and methane)
Coal, steam and oxygen are
burned under pressure in the
gasif ier. yielding a gas com-
posed mostly of carbon mon-
oxide and hydrogen. That
gas is passed over a catalyst
to produce fuel gas and
liquid fuels.
Figure 1. South Africa's Sasol Process
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Coal 1s a solid fuel. If coal 1s to be more flexible for America's current
market requirements, 1t must be converted to the gas and liquid energy
forms that meet today's needs. For this reason, the South African Sasol
process 1s of great Interest to Americans.
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2. Historical Background
South Africa has large deposits of low grade coal but no deposits of
oil have ever been found. The country depends on coal for about 80% of
Its energy needs, more than any other modern Industrial nation. The
possibility of producing hydrocarbons from coal has always attracted the
attention of Its scientists. In 1927, a White Paper was published
discussing the available processes for the production of 611 from coal.
Developments 1n Germany were closely followed, especially after the first
announcements of the commercial feasibility of the F1scher-Tropsch process
for the conversion of coal gas(to liquid hydrocarbons were made 1n 1935.
Between 1936 and 1939, nine plants, with a total rated annual output of
820,000 tons (740,000 metric tons, mt) of synthetic oil, were erected In
Germany. The synthetic fuel Industry developed by the Germans during the
war was highly uneconomical but 1t provided gasoline for tanks, trucks,
and planes. Of their final products, 46% was gasoline, 23% dlesel oil,
3% lubricating oil, and 28% was refined waxes, detergents, and synthetic
fat. After the war, the relative costs of coal and oil dictated the
shutdown of the German synthetic fuel Industry. Germany has done little
1n the field since.
The first large-scale German plant was still under construction 1n
1935 when a South African mining corporation, the Anglo Transvaal Con*
solldated Investment Company, better known as Anglo Vaal, acquired the
South African rights to the F1scher-Tropsch process. Valuable pioneering
work was done by Anglo Vaal In the 1930's. Preliminary tests were carried
out on coal found 1n the eastern Transvaal district of South Africa, and
during 1937 a complete specification for a suitable plant was drawn up.
Tenders were Invited but progress on the project was Interrupted by the
outbreak of World War II 1n 1939.
United States scientists and engineers had been frequent visitors to
Germany during the 1930's. During that time the United States was working
on Its own variation to the F1scher-Tropsch process which used a moving
powdered catalyst rather than the stationary pelletlzed catalyst developed
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by the Germans. South African Interests acquired rights to the American
version of the Flscher-Tropsch process toward the end of the war.
In 1946 a new study was made and negotiations started with the South
African government for an agreement on the fiscal structure within which
an oll-from-coal plant could be established. In 1947, the Liquid Fuel
and 011 Act was passed and a Liquid Fuel Advisory Board was established.
It was evident that the new Industry would be one of the biggest single
enterprises ever established In South Africa and that Its success would
very much depend on such factors as government policies and taxation.
The Advisory Board was Instructed to examine all factors Involved and to
draw up a license which would give this new Industry security for at
least a number of years. This license was finalized 1n 1949.
By that time. Orange Free State gold mining expansion was 1n full
swing and capital for less spectacular operations was scarce. At this
stage, the sponsoring company approached the government for financial
assistance. The great capital outlay required for the erection of a plant
was beyond the means of Anglo Vaal. An Interim Commission appointed by
the government to examine the proposed undertaking recommended that the
process should be taken over from Anglo Vaal and that a government
financed company should proceed with the venture.
The South African Coal, 011, and Gas Corporation Ltd. (Sasol) was
formed and Incorporated under the Companies Act 1n September 1950 as an
ordinary public company. It Is not a government company 1n the normally
accepted sense, but all Its shares are held by the Industrial Development
Corporation, a government company with Its own charter. The government
appoints the majority of directors, Including the chairman, and the re-
maining directors are appointed by the Industrial Development Corporation.
Sasol operates like a normal business concern, with an autonomous board
of directors and Is subject to South African company law and taxation.
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The new company Invited several Internationally known engineering
firms to submit suitable proposals with estimated costs for a complete
Installation. After examining the five offers received It became clear
that Important technical and economic advantages would result 1f the
processes submitted by one German and one United States company were
combined Into an Integrated project.
The Ideal site for the oll-from-coal plant proved to be the northern
corner of the Free State. Here a vast coal field exists close to the Vaal
River and the concentrated market of the country's Industrial center of
the Wltwatersrand. Sasol acquired 8000 acres (3000 hectare) of farmland for
the erection of Its factory complex and the establishment of the township
of Sasolburg.
Shaft sinking at Sasol's coal mine and the planning of the plant and
the township commenced In 1951. In 1955 reaction was accomplished for
the first time 1n the synthesis reactors. By the end of the year the
first motorists filled up their tanks with Sasol gasoline. Sasol's total
capital Investment was In the vicinity' of $450 million.
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3. Sasol I, Sasol II, Sasol III
The successful operation of the first Sasol plant (hereafter referred
to as Sasol I) represented a major pioneering achievement In the area of
coal technology. Sasol I Is a vast complex which Includes 1n addition to
Its o1l-from-coal plant, a refinery and facilities for producing Important
Industrial petrochemical feedstocks. The plant presently 1s the only fully
Integrated commercial synthetic fuels from coal plant In the world. Despite
many technical difficulties that had to be overcome during the aarly years
after startup, In most cases the actual output now exceeds the design figure.
Sasol I converts five million tons (4.5 million mt) of coal per year to
160 million gallons (600 million liters) of gasoline plus vast quantities
of liquid and gaseous fuels and petrochemicals. And contrary to early
predictions, Sasol I has turned Into a commercially profitable undertaking.
Pretax profits 1n 1978 were $140 million on sales that totaled close to
$1 billion. The oil produced by Sasol I Is better quality than normal
crude oil because the sulfur and other Impurities have already been re-
moved before the refining step. Gasoline from Sasol 1s Indistinguishable
In look and smell from gasoline refined from crude oil and no problems
have been experienced 1n using liquid fuels from Sasol 1n blends for
regular and premium gasoline and dlesel oil. Gasoline from Sasol I
accounts for about 7% of the market 1n South Africa.
The first step 1n the production of oil 1s the gasification of coal.
Lurgl pressure gaslflers using steam and oxygen were selected because their
operablUty had already been demonstrated and they had the advantage of
being able to work on the low grade, high ash coal available to Sasol.
The crude synthesis gas from the Lurgl gaslflers 1s fed to a gas purifica-
tion unit where It 1s scrubbed with methanol to remove sulfur, carbon
dioxide, tars, oil, phenols, ammonia, cyanides, and other unwanted com-
ponents. The purified synthesis gas then undergoes the Flscher-Tropsch
synthesis process, the combination of hydrogen and carbon monoxide with
the aid of an Iron catalyst to produce a range of hydrocarbons Including
motor fuels.
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Two Flscher-Tropsch synthesis processes are used at Sasol I: the
German developed process In which the pelletlzed catalyst 1s packed
Into a fixed bed reactor, and the American concept 1n which the powdered
catalyst 1s swept along by the gas stream In a circulating fluid bed reactor
system. The first process produces mainly higher boiling point materials
consisting of waxes, some oils with medium boiling point such as dlesel
oils, and smaller amounts of gasoline, liquefied petroleum gas and chemicals.
In contrast, the second process produces mainly low boiling point materials
such as liquefied petroleum gas and gasoline as well as a considerable
amount of chemicals such as alcohol and acetone. The unique combination
of the two processes yields virtually the full range of products normally
derived from crude oil In addition to a number of others usually manu-
factured 1n petrochemical plants. Sasol I 1s also the major supplier of
Industrial gas via a high-pressure pipeline to South Africa's Industrial
areas.
Sasol I has become the hub of South Africa's chemical Industry, a
group of about 30 plants producing a large range of petrochemical products:
fertilizers, plastics, synthetic rubber, detergents, chemicals. In order
to meet the ever growing demand for Its products, Sasol I has successfully
Initiated and completed Improvement and expansion programs over the years
to supply Important feedstocks (butadiene, styrene, ammonia, ethylene) to
the chemical Industry. In addition, 1n 1975 Sasol I Implemented a $65
million expansion program which Increased the capacity of the gasification
plant by 40% and which doubled the supply of Industrial gas.
As a result of rising crude oil prices since the Yom Klppur War (1974)
and the Arab oil boycott, the South African government 1n a major move away
from dependence on Imported crude oil announced 1n December 1974 that 1t
would build a second oil-from-coal complex, Sasol II. In addition, the
move will save considerable sums 1n foreign exchange which South Africa
uses to pay for Imported oil. Sasol II will be three times the design
capacity of Sasol I, or In terms of petroleum production, Sasol II will
be the equivalent of a refinery capable of refining 2.9 million tons (2.6
million mt) per year of crude oil. The plant will consume 14 million tons
(12.8 million mt} per year of coal as compared with five million tons
(4.5 million mt) at Sasol I. .
o
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Sasol II 1s based on the same technology as Sasol I, that 1s, Lurgl
gaslflers followed by the Flscher-Tropsch synthesis. Sasol I uses both
the fixed bed and circulating fluid bed synthesis processes to produce the
full range of light to heavy hydrocarbons. However, the objective of
Sasol II 1s to produce motor fuels (gasoline and dlesel) for which the
circulating fluid bed Is more suited. In addition, the possibilities for
scale up are limited for the fixed bed reactor. For these reasons, the
Sasol II plant will use only circulating fluid bed synthesis reactors
which were perfected at Sasol I.
Construction got under way In 1976 on a flat, treeless 1850 acre
(750 hectare) site about 80 miles (130 km) east of Johannesburg. The work
force reached 15,000 during peak construction and the plant 1s scheduled
for completion early In 1980. In addition, a town called Secunda (Latin
for second) Is being built nearby. The Sasol II complex will produce
enough gasoline to supply 30% of South Africa's motor fuel needs. Sasol
II will cost $2.8 billion and 1s being financed by Increased gasoline
levies, by suppliers' credits, and by government-voted money. To put the
cost In perspective, South Africa expected to spend $2.3 billion on
Imported oil 1n 1979.
Immediately after the downfall of the Shah of Iran 1n early 1979,
South Africa announced the planned construction of Sasol III alongside
Sasol II. The new Iranian revolutionary government had decided to cut off
oil supplies to South Africa. Iran had been South Africa's principal
supplier. Sasol III will be almost an exact copy of Sasol II to save
design costs, and may be ready for full production by 1984. Because of
Inflation, construction costs for Sasol III are estimated at $3.8 billion.
Once the three plants are 1n operation, they will produce about 112,000
barrels of oil per day, approximately half of South Africa's needs 1n the
1980's.
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4. Detailed Description of the Process
The Sasol I complex 1s made up of the following processing units:
• Coal mining and preparation
• Coal gasification
• Oxygen and steam production
• Gas purification
• Flscher-Tropsch synthesis
• Recovery and treatment of gaseous products
• Reforming of methane to synthesis gas
e Recovery and refining of liquid products
The Sasol II and Sasol III complexes with some modifications consist
of the same processing units. The units that make up a Sasol plant along
with the reasons for their selection are described 1n this section.
Differences between the three Sasol plants will be pointed out. A block
diagram of the Sasol I process 1s shown 1n Figure 2.
4.1 Sasol I
Sasol I 1s located 50 miles (80 km) south of Johannesburg on top of a
vast coal field close to the banks of the Vaal River which 1s South Africa's
major source of water. Sasol I Is supplied with coal from Its own nearby
mine, Sigma Colliery. Production amounts to five million tons (4.5 million
mt) per year. Sigma produces a non-caking, low-grade coal with an ash
content of 30 to 35%, a sulfur content of 0.5%, and a heating value of
8380 Btu's per pound (19,480 kJ/kg) on a dry basis. A typical analysis Is
shown 1n Table 1. The coal 1s present 1n three seams, having mineable
heights of 8 to 10 feet (2.5 to 3m) each. The seams are separated by
layers of shale, mudstone, and sandstone of varying thickness. The mine
1s under 100 to 200 feet (30 to 60 m) of white sandstone.
The mining technique used 1s the mechanized room-and-pWar. The
coal recovery efficiency 1s approximately 52%. Mined coal 1s transported
via conveyor to primary crushers situated at the bottom of the Inclined
coal hauling shafts. The coal 1s lifted to the surface by conveyor and
discharged Into storage bunkers of 12,000 ton (11,000 mt) total capacity.
10
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AIR ^
OXYGEN
PLANT
COAL HIKE coAL_
AND *
PREPABATIDM
POWER
PLANT
OXYGEN _
STEAM
_J_
| COAL 1 ^ SASIFI
ASH 1
~ LUR
1 ,
\
GJ
COOI
\
x SULFUR .TrrTronD /V H2S PURIF1
\
1
FT7F.D BED
SYNTHESIS
ARPF
\
1
i
CATION!
GI 1
RAW
,GAS :
li<> -w
LING
*—
CATION!
•ISOL 1
(PURE
GAS
,
PRODUCT TAIL . METHANE
RECOVERY GAS
LIC
PROD
i
UID INDU!
UCTS fl
~ REFORMER
TAIL GAS
5TRIAL
^S
hi PHFNfKni VAN
JL TAR J
*|DISTILLATION|
FLUib otu
j»i SYNTHF^T*;
5YMTHr>l
i i
PRODUCT
RECOVERY
\ '
LIQUID
PRODUCTS
Figure 2. Block Diagram of Sasol I Process
11
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Table 1. Typical Analysis of Sasol Coal
Sasol I Sasol II
Dry Basis
Ash 35.9 % 27 %
Volatlles 22.3 25
Fixed Carbon 41.8 48
Ultimate Analysis as Received
Carbon 45.4 % 54.2 %
Sulfur 0.4 1.1
Nitrogen 1.1 1.3
Hydrogen 2.5 2.9
Oxygen 7.9 9.4
Ash 32.0 25.6
Moisture 10.7 5.5
Total 100.0 % 100.0 X
Ash Properties
Softening Point 2440°F (1340°C) 2350°F (1290°C)
Melting Point 2600°F (1430°C) 2430°F (1330°C)
Fluid Point 2690*F (1475°C) 2480°F (1360°C)
Gross Heating Value (dry) 8,380 Btu/lb 10,300 Btu/lb
(19,480 kJ/kg) (23,940 kj/kg)
12
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Surface conveyor belts transport the coal from the storage bunkers to the
secondary crushers and screens. The final product consists of two coal
sizes, less than 0.4 Inch (1 cm) and between 0.4 and 2 Inches (1 and 5 cm),
which are transferred separately on twin conveyors to the 60,000 ton
(54,000 mt) Sasol factory storage bunkers. Coal Is kept damp on the con-
veyor belts by water sprays at suitable points to prevent dust formation.
The less than 0.4 Inch (1 cm) fraction (approximately SOX of the total)
1s used 1n the power plant to produce electric power and heat for steam
production, whereas, the 0.4 to 2 Inch (1 to 5 cm) fraction Is fed to the
Lurgl gaslfiers.
The Lurgl pressure gaslfiers are fixed-bed, water-cooled reactors
that gasify the coal In the presence of oxygen and steam to yield a syn-
thesis gas containing methane, carbon monoxide, hydrogen, carbon dioxide,
ammonia, hydrogen sulflde, steam, and numerous other compounds. Lurgl
pressure gaslfiers were selected because they had already been demonstrated
1n smaller sized Installations and had the advantage of being able to
work on the rather low grade, high ash coal available to Sasol I. The
fact that they operated at a pressure of approximately 350 ps1 (2400 kPa)
which was also the desired operating pressure for the Flscher-Tropsch plant
was an additional advantage.
Thirteen Lurgl gaslfiers consume coal at a total rate of approximately
8,000 tons (7300 mt) per day. These gaslfiers are 12 feet (3.7 m) 1n
diameter and are the largest of their kind In commercial operation. On an
annual basis, 10.8 out of 13 gaslfiers are In service. At this level, gas
production 1s actually limited not by gasification but rather by gas
purification capacities. The Lurgl gaslfiers operate on the principle of
countercurrent flow of coal to steam and oxygen which offers the best
conditions for heat and mass transfer and optimum efficiency. The overall
thermal efficiency of the gaslfler system 1s approximately 75.5%. Gasi-
fication occurs at 1800°F (1000°C).
Consumption of oxygen and steam 1n the Lurgl gaslfiers 1s a function
of a number of variables, but typical Sasol values are 220 standard (0°C,
o
1 atm) cubic feet (SCF) of oxygen (6.2 Mm) and 62 pounds (28 kg) of steam
•5
per 1000 SCF (28 Mm ) of raw synthesis gas produced. Raw gas production
13
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averages 330 million SCF (9.3 million Mm ) per day. Oxygen Is produced In
one of the world's largest air separation plants. About 13,000 tons
(12,000 mt) of air are compressed and cooled down to -310°F (-190°C) every
day In order to separate the oxygen and nitrogen and recover them 1n liquid
form. The oxygen Is used 1n the Lurgl gaslffers as well as 1n the partial
oxidation methane reforming plant. The nitrogen Is used 1n an ammonia plant.
Steam and electricity are generated In a power plant which consumes
approximately 7,000 tons (6400 mt) of coal per day or 50% of the coal
supplied to the Sasol I plant. Conventional pulverized fuel boilers are
used. The steam generated Is used not only for the gasification of coal,
but also 1n the various plants Inside and outside the Sasol complex.
Sasol I coal contains 30 to 35% ash which must be disposed of. The
residual carbon 1s completely burned out of the ash with oxygen 1n the
combustion zone at the bottom of the Lurgl gaslflers. This exothermic
reaction helps supply the heat for the endothermic gasification reaction
In the upper part of the gaslflers. The residue 1s essentially burned-out
ash which Is transported from the gasification and power plant areas by
water In a low velocity sluiceway to the ash dewaterlng unit. Coarse
ash 1s removed by conveyor belts to an ash dump. The fine ash 1s concen-
trated 1n a thickener and the concentrated fine ash 1s then dewatered 1n
a slimes dam. The ash contains soluble Inorganic salts that will leach
out. The ash system 1s however an evaporative system for water and re-
quires water make-up and no purge. Hater drainage from the slimes dam
1s collected and pumped back Into the ash sluiceway system. To prevent
water seepage, the slimes dam was given an Impervious clay layer from
clay available on site. The slimes dam was built with an extensive drain-
age system to recover all seepage for return to the ash sluiceway system.
Coarse ash contains no excess water and at least the outside of the
dump soon dries out to such an extent that It will absorb rain water.
No evidence of seepage from the ash dump has been found and no measures
are taken against seepage. Success has been achieved In growing grass
on the dumps to make them aesthetically acceptable. Regular samples of
water from boreholes 1n the vicinity of Sasolburg have been taken over
the years and no evidence of underground water pollution has been found.
14
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Raw synthesis gas leaving the top of the gaslflers contains apart
from carbon monoxide and hydrogen appreciable quantities of methane, car-
bon dioxide, hydrogen sulflde, and undecomposed steam. In addition, the
gas contains cyanide compounds, tars, oils, phenols, organic sulfur com-
pounds, and numerous other Impurities 1n minor quantities. The Iron-
containing Flscher-Tropsch catalyst Is very sensitive to sulfur, cyanide,
and other compounds. Efficient purification of the synthesis gas Is an
essential requirement for high Flscher-Tropsch conversion rates. In
addition, the raw gas contains about 30% carbon dioxide which must be
brought down to a lower level.
After separation of entrained coal dust, the raw synthesis gas 1s
cooled 1n a sequence of waste heat boilers and condensers. The raw gas
contains large quantities of undecomposed gasification steam. During gas
cooling this steam Is condensed and the resulting aqueous 11quor contains
the water-soluble components that were 1n the gas, chiefly phenols and
ammonia. The tars and oils are also separated from the synthesis gas
during cooling. The oil and aqueous liquor streams are fed to tar distilla-
tion and Phenosolvan plants respectively. In the tar distillation plant,
road primer, creosotes, and lighter naphthas fractions are separated. The
naphthas are hydrogenated and distilled to produce benzoles for solvent use
and for blending Into gasoline. In the Phenosolvan plant, the aqueous liquor
Is treated by solvent extraction with an oxygen-containing organic solvent,
butyl acetate, to remove the phenol compounds. The ammonia Is then recovered
by stripping with steam and converted to ammonium sulfate for fertilizer
manufacture. There are 5.5 U.S. gallons of tar and oil and 17 pounds of
ammonia recovered per short ton of coal gasified (23 liters and 8.5 kg per mt),
Stripped liquor, containing approximately 240 and 250 parts per million
(ppm) of ammonia and phenol, Is processed In a conventional biological treat-
ment plant together with effluents from other chemical plants In the area, as
well as domestic sewage from the town of Sasolburg. Treated liquor 1s used
1n the factory for removal and transport of ash from the gaslflers. Ash acts
as an adsorbent, reducing the residual oil content of treated liquor to less
than 2.5 ppm.
15
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Cooled synthesis gas leaving the waste heat boilers and condensers
still contain Impurities, Including carbon dioxide, hydrogen sulflde, and
an array of gum-forming compounds. These Impurities are removed by
methanol In the Rectlsol plant. The Rectlsol process 1s based on the
capability of one solvent, cold methanol, to absorb all Impurities present
In gases from coal gasification tn a single process step. Since the ab-
sorption capacity of methanol Increases with decreasing temperature, the
raw gas 1s contacted and scrubbed with liquid methanol at -67°F (-55°C).
At Sasol I, the Rectlsol process (a total of four parallel streams) has
a long term on stream record of 97%, and produces a purified gas containing
1.51 carbon dioxide and 0.07 ppm hydrogen sulflde. A typical composition
of raw and pure synthesis gas Is shown In Table 2. The extremely pure gas
from the Rectlsol process 1s suitable for the sensitive Flscher-Tropsch
synthesis catalyst. The main energy consumption In the Rectlsol unit 1s
that used to drive the methanol circulation pumps and the refrigeration
compressors. Approximately 0.9 KWH and 4.6 pounds (2 kg) of steam per
1000 SCF (28 Nm3) of purified gas leaving the Rectlsol process are required.
The off-gas (containing carbon dioxide and hydrogen sulflde) from the
Rectlsol plant 1s used as an expansion gas. Before this gas 1s vented to
the atmosphere, hydrogen sulflde 1s removed and recovered as elemental
sulfur 1n a Stretford sulfur recovery unit. The Stretford unit was
Installed In 1976. The limit set for gaseous effluents from the Stretford
units both at Sasol I and Sasol II 1s 50 ppm hydrogen sulflde. Some hydro-
carbons and other Impurities are still present 1n the vent gas.
The purified gas emerging from the Rectlsol plant undergoes the
Flscher-Tropsch synthesis which produces hydrocarbons by the catalytic
conversion of carbon dioxide and hydrogen according to the following
equation:
n(CO + 2H2) -*• (-CH2-)n + nH20
16
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Table 2. Typical Composition of Raw and Pure
Synthesis Gas (Volume %)
Component Raw Gas Pure Gas
C02 31.4 1.2
H2 40.2 54.0
CO 17.1 30.5
CH4 10.2 13.6
H2S 0.3
N2+Ar 0.4 0.6
0.4 0.1
17
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Two types of Flscher-Tropsch reactors are used, the German developed fixed
bed process (Arge) and the American fluid bed system (Synthol). The
purified gas from the Rectlsol plant 1s divided Into two streams. The
larger stream Is fed directly to the fixed bed Arge synthesis units where
a stationary pellet1zed catalyst Is used. The gas conversion Is not
complete. The tall gas from the Arge units contains 1ow-bo1l1ng hydro-
carbons and carbon dioxide. These are removed In a Rectlsol wash unit
at subzero temperatures. The washed gas together with the remainder of
the fresh gas from the purification plant enters a reforming plant where
methane Is reacted with steam and oxygen over a nickel catalyst to produce
additional carbon monoxide and hydrogen. After adjustment of the hydrogen-
carbon monoxide ratio, the gas 1s fed to the fluid bed Synthol plant where
a circulating powdered catalyst 1s used. The tall gas of this plant Is
also recycled to the reforming units after removal of carbon dioxide.
For both the Arge and Synthol plants there are recovery and refining
plants downstream.
The fixed bed reactor produces In general straight-chain hydrocarbons
with a high average molecular weight In the range of dlesel oil and
parafln waxes and a relatively low percentage of gasoline, liquefied
petroleum gas, and oxygenated compounds (alcohols, ketones, organic adds),
The fluid bed process produces branched oleflns of a lower average molecu-
lar weight 1n the range of liquefied petroleum gas and gasoline, little
h1gh-bo111ng material, and some oxygenated products (Table 3). Although
the basic chemistry for both reactors Is the same, the different tempera-
tures, method of catalyst contacting, recycle ratios, feed gas composi-
tions, and hydrogen partial pressures employed 1n the two systems result
not only 1n a difference In product selectivity, but also 1n a difference
1n the properties of hydrocarbons within the same boiling range. In
general, the higher the reaction temperature the higher the content of
oleflns and the lower the average molecular weight of the products.
18
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Table 3. Comparison of Fixed Bed and Fluid Bed
Conditions and Products
Fixed Bed Fluid Bed
Conditions
Temperature 430-490°F (220-255°C) 625°F (330°C)
Pressure 360 pslg (2500 kPa) 330 pslg (2300 kPa)
CO + H2 Conversion, % 65 85
H2/CO Ratio 1n Feed 1.7 2.8
Product Composition. Vol %
Liquefied Petroleum Gas (C3-C4) 5.6 7.7
Petroleum (Cg-C^) 33.4 72.3
Middle 011s (dlesel, furnace) 16.6 3.4
Waxy Oil 10.3 3.0
Medium Wax, mp 135-140°F (59°C) 11.8
Hard Wax, mp 203-206°F (96°C) 18.0
Alcohols and Ketones 4.3 12.6
Organic Acids trace 1.0
Product Selectivity, Vol % C5-C,2 C13-C18 C5-C10 Cn-C14
Paraffins 53 65 13 15
Oleflns 40 28 70 60
Aroma tics 0 0 5 15
Alcohols 66 65
Carbonyls 11 65
19
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The fixed bed Arge system (a joint development of Ruhrchenrie and Lurgl
of Germany) consists of five reactors In parallel, each with a shell of
approximately 10 feet (3 m) In diameter and a height of 42 feet (13 m).
Inside each shell there are 2,000 vertical tubes, 2 Inches (5 cm) In
diameter, containing the pelletlzed Iron catalyst. The tubes are surrounded
on the shell side by a steam jacket. The gas Is passed over the catalyst
from top to bottom and the heat released by the exothermic reaction 1s
absorbed by boiling the water In the shell. The reaction temperature Is
controlled by controlling the pressure of the boiling water. The Flscher-
Tropsch reactions are highly exothermic, and one of the major design
problems for both the Arge and Synthol systems Is adequate heat removal
from the reactor. About 7,500 Btu's of heat are released per pound of
product (17,400 kJ/kg).
Figure 3 Is a schematic drawing of the fixed bed Arge reactor. The
reactor operates at 360 pslg (2500 kPa). The life of the Iron catalyst 1s
six months during which time the operating temperature 1s Increased from
the starting point of 430°F (220°C) to a maximum of 490°F (255°C). The
specific catalyst employed contains a number of promoters (Including copper
and potassium) and has to be partially reduced before It can be used. It
1s manufactured at Sasol.
The fixed bed synthesis accounts for about one-third of Sasol I's
plant output. It came on line In 1955 with only minor problems and behaved
more or less as designed. Production up to 140% of the design capacity
has been achieved. The major disadvantage of the Arge reactor system 1s
Its limited scale-up potential. New, large synthetic fuel plants would
require an Impractical number of such reactors.
The synthesis products exit at the bottom of the Arge reactor. The
tall gas 1s separated from the heaviest hydrocarbons which are obtained as
reactor condensate. The hot gas then exchanges heat with the Incoming
feed gas and Is further cooled and washed with sodium hydroxide solution
In water-cooled condensers. The heat exchangers and the condensers
produce hydrocarbon and aqueous condensates which are, after pressure
release and recovery of the dissolved gas, sent to the refinery.
20
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STEAM
COLLECTOR
TUBE BUNDLE
GAS INLET
STEAM HEATER
•- STEAM OUTLET
FEEDWATER INLET
INNER SHELL
»~GAS OUTLET
*" WAX OUTLET
Figure 3. Fixed Bed Arge Reactor
21
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The tall gas leaving the condensers Is used for recycle, sold as
Industrial gas, or Is sent to a methane reformer. The tall gas contains
low-boiling hydrocarbons up to pentane, Inclusively, and carbon dioxide.
The hydrocarbons are removed In a Rectlsol wash unit by heptane at -30°F
(-35°C). followed by a methanol wash at -40°F (-40°C) to prevent a buildup
of carbon dioxide. The washed gas together with fresh gas from the purifi-
cation plant and tall gas from the fluid bed Synthol reactors 1s sent to a
reforming plant where methane Is reacted with steam and oxygen over a nickel
catalyst at a temperature of about 1800°F (1000°C) to produce additional
carbon monoxide and hydrogen. The Lurgl gaslflers and both Hscher-Tropsch
synthesis processes produce methane as the lowest hydrocarbon and there 1s
a tendency for methane to build up 1n the recycle streams. To make full
use of the synthesis gas, It Is necessary to reform methane back to hydrogen
and carbon monoxide. Another complication Is the presence of nitrogen and
argon 1n the synthesis gas, most of which Is Introduced Into the gas stream
with the 98% oxygen from the air separation plant. The nitrogen and argon
act as Inerts In the system and have to be removed as a purge gas to keep
them within an acceptable level.
The gas from the reforming plant Is fed to the fluid bed Synthol plant.
The Synthol process was developed by M.W. Kellogg of the United States.
Each Synthol reactor consists of a feed system, a reactor tube, product-
catalyst separation equipment, and a catalyst recycle hopper (Figure 4).
Fresh feed and recycle gas at 320°F (160aC) are blended with finely divided,
hot 625°F (330°C) Iron catalyst at the base of the reactor. This gas-solid
mixture comes rapidly to thermal equilibrium and rises up the Synthol reactor
where exothermic Flscher-Tropsch and water-gas shift reactions take place.
A significant fraction of the heat liberated Is removed 1n waste heat
boilers built Into the reactor. In addition, the products and tall gas
leaving the system at 625°F (330°C) remove a large amount of heat. The
products are disengaged from the catalyst Initially by gravity and sub-
sequently by cyclone separation. The gas leaves the reactor and the
recovered catalyst Is collected 1n a settling hopper from which 1t 1s
recycled through a stand pipe and slide valves to the feed gas Inlet at
the base of the reactor.
22
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TAIL GAS AND
S?S
SYNTHESIS PRODUCTS'
CYCLONES
CATALYST SETTLING
HOPPER
CATALYST
STANDPIPE
SLIDE VALVES
FRESH FEED
AND RECYCLE
COOLING
OIL OUTLET
REACTOR
RISER
GAS AND CATALYST
~ MIXTURE
Figure 4. Fluid Bed Synthol Reactor
23
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Three parallel Synthol reactors are 1n operation at Sasol I. Each has
an Inside diameter of seven feet (2 m), and a height of 120 feet (37 m).
The reactors operate at 330 pslg (2300 kPa) and 600 to 625°F (315 to 330°C).
An ammonia synthesis type Iron catalyst containing various structual pro-
motors such as alumina and magnesium oxide 1s circulated through each
reactor at a rate of 6,000 to 8,000 tons (5500 to 7000 mt) per hour. The
reduced Iron catalyst 1s gradually converted during synthesis Into a
mixture of free Iron, Iron carbides, and magnetite. The catalyst used 1n
the fluid bed reactors was developed by Sasol.
At the time the Synthol plant was designed only pilot plant data were
available. However, when the flutd bed plant was built, 1t behaved quite
differently from what was predicted. Much additional experimentation,
research, and modifications were needed at Sasol before the fluid bed
system was developed to the point where It could be considered completely
reliable. In contrast to the Arge reactor system, the Synthol reactors
have distinct scale-up capability and are, therefore, practical for use
In the large-scale synthesis of hydrocarbons. Fluid bed reactors will be
used exclusively In Sasol II and III.
The products of the Synthol reactors and the tall gas are passed to a
scrubber where the vapor 1s cooled from the reactor outlet temperature of
625°F to 300°F (330 to 150°C). The higher molecular weight hydrocarbons
are condensed and separated. The heavy hydrocarbons are taken off the
bottom of the scrubber and sent to the oil recovery plant. The vapor phase
scrubber overhead Is further cooled and sent to a separator where lighter
hydrocarbons, aqueous chemicals, and the gas phase are separated. The light
hydrocarbon layer Is transferred to a countercurrent water-wash tower
where any oxygenated products Including alcohols, ketones, and organic
adds are washed out. The washing water 1s added to the aqueous stream
from the separator and sent to chemical recovery. A significant fraction
of the non-condens1ble product gas from the separator 1s boosted to the
reactor Inlet pressure and recycled. The remaining tall gas Is washed
with an alkali solution and passed to an absorption system for recovery
of light hydrocarbons. The absorber effluent gas 1s rich 1n methane
and hydrogen. It 1s either used 1n ammonia synthesis, sold as Industrial
24
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gas, or reformed to carbon monoxide and hydrogen for recycle. When used 1n
ammonia synthesis, hydrogen Is separated from the Synthol tall gas by cool-
1ng to -315°F (-193°C). The hydrogen 1s then mixed with a correct amount of
pure compressed nitrogen from the air separation plant and converted over
an Iron oxide catalyst to synthetic ammonia. The ammonia 1s converted to
nitrogenous products for use In South Africa's agricultural Industry. The
methane fraction from the low temperature hydrogen separation unit 1s used
as a blending gas to help control the heating value of the tall gas sold
to Industry. The clean fuel gas supplied to the nearby Industrial areas
of the Vaal Triangle and the Wltwatersrand has a heating value of 500 Btu's
per standard cubfc foot (18,600 kJ/Nm ). To meet the Increasing demand for
Industrial gas, the coal gasification capacity of Sasol I was Increased by
40% 1n the mid-19701s, doubling the supply of gas to Industry. The ex-
pansion consisted of additional gaslflers, a Rectlsol purification unit,
additional oxygen capacity, and an aqueous liquor purification unit.
With the building of Sasol I, the South African petrochemical Industry
was firmly established. The solid hydrocarbons from the fixed bed process
find many applications. The primary gasoline produced 1s a suitable motor
fuel and the dlesel oil Is of an excellent quality. The liquid oleffns
provide raw materials for biologically soft detergents, and a wide range
of high-viscosity, stable, lubricating oils. In addition, alcohols,
ketones, aldehydes, organic adds, and esters are recovered from the
aqueous streams that flow from the synthesis reactors. A partial 11st of
Sasol products 1s presented 1n Table 4. The overall thermal efficiency
of the Sasol process from coal as mined to saleable refined end products
1s 35 to 40%.
4.2 Sasol II and Sasol III
Early in 1980, South Africa's production of gaseous and liquid hydro-
carbons from coal will triple with the startup of Sasol II, a $2.8 billion
complex based on the same coal conversion and Fischer-Tropsch technology
as Sasol I. Sasol I and II will produce enough gasoline to meet 30 to 40%
of South Africa's needs,
25
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Table 4. Sasol Products and Intermediates
Carbon Dioxide
Oxygen
Nitrogen
Steam
Electricity
Ammonia
Ammonium Nitrate
Ammonium Sulfate
Phenol
Benzene
Toluene
Road Primer
Fuel Oil
Xylenol
Light Naptha
Heavy Naptha
Reactor Wax
Soft Waxes
Medium Waxes
Hard Waxes
Paraffin
Gasoline
Diesel 011
Creosote
Liquefied Petroleum Gas
Industrial Gas
Acetone
Methyl Ethyl Ketone
Higher Ketones
Methanol
Ethanol
Higher Alcohols
Ethylene
Butadiene
Styrene
Pitch
26
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Sasol II will concentrate on the manufacture of refined motor fuel
rather than petrochemicals, although petrochemicals will be produced. The
grass roots plant will produce 2.4 million tons (2.1 million mt) per year
of saleable products, Including 1.7 million tons (1.5 million mt) per year
of gasoline and dlesel oil. Sasol II Is being financed by gasoline levies,
suppliers' credits, and government-voted money. The rising cost of crude
oil should make Sasol II economically very attractive when It comes on
stream 1n 1980. This has been the case with Sasol I 1n recent years.
Sasol production costs amount to $17 per barrel. This Is well below the
OPEC price of around $20 per barrel and much less than the $31 per barrel
that South Africa has to pay on the spot market. Gasoline sells for about
$2.40 a gallon (63
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The total amount of coal consumed by Sasol II will be approximately
14 million tons (12.8 million mt) per year of which 9.2 million tons (8.4
million mt) will be gasified and 4.8 million tons (4.4 million mt) used for
steam and power production. The steam production will be between four and
five million pounds (about 2 million kg) per hour and the power produc-
tion will be 240 megawatts. Additional power will be bought from the pub-
lic utility system which operates large power plants 1n the Sasol II area.
Coal for Sasol II Is higher 1n carbon and lower 1n ash than Sasol I
coal (Table 1). Since Sasol II coal Is very friable, crushing and screen-
Ing to the same size as for Sasol I would result 1n a higher proportion
of fines than Is desirable for gasification. Fines In coal fed to the
gaslflers can be carried out with the raw synthesis gas and be not only
a loss to the process but result 1n underslrable problems with the gasi-
fication by-products. Wet screening of Sasol II coal will permit a sharp
separation of the fines. The fines will be used 1n the generation of steam
and power for Sasol II. In fact, the amount of power production was chosen
to arrive at a balance between fine and coarse coal.
The coarser coal 1s fed to the coal gasification plant. The choice
as to which gasification system to use was between the Lurgl pressure
gaslfler with which Sasol 1s completely familiar and a high temperature,
low pressure entrained gaslfler system using pulverized coal. As a
result of the high temperature, the latter system does not produce coal
gasification by-products, nor does 1t produce methane, but Its oxygen
consumption 1s high and the raw gas needs compression to bring It to an
acceptable level for purification. The Lurgl pressure gasification has
the advantage for the Sasol objective that gas Is produced approximately
at the pressure required for the Flscher-Tropsch synthesis so that com-
pression of large volumes of raw gas Is not required. In a large plant
such as Sasol II, processing facilities for the gasification by-products
can be economically justified especially where the overall objective of
the plant Is to produce hydrocarbons. All these considerations expressed
In terms of capital Investment, operating cost and Income Indicated that
28
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for Sasol II* Lurgl gaslflers will again be used. Over the years a number
of Improvements to the Lurgl gaslfier have been made allowing the extra-
polation to larger capacity within the limits of confidence. Sasol II
will require 13,000 tons (12,000 mt) of oxygen per day from air separation
plants.
For the gas purification section, a large number of options were
available to remove not only the last traces of tar and tar products but
also organic sulfur and hydrogen sulflde as well as carbon dioxide. Only
the Rectlsol process with methanol could do all these things 1n one single
module. Although the objectives of the purification sections of Sasol I
and II are the same, differences In the processing schemes do exist. For
example, Sasol II will recover ammonia as anhydrous ammonia while Sasol I
reacts ammonia vapors with sulfurlc acid to produce ammonium sulfate.
Also, Sasol II will make more use of air cooling.
The purified gas from the Rectlsol process, containing less than 0.07
ppm sulfur, 1s sent to the Flscher-Tropsch synthesis. Sasol I has two
types of synthesis: a fixed bed system which produces a high percent of
heavier paraffin hydrocarbons for which a low volume market exists and a
fluid bed system which produces more oleflns and lighter hydrocarbons In
the gasoline and dlesel range. The fixed bed reactors have the draw-back
that their possibilities for scale up are limited and their total capacity
1s small. At Sasol I, a reactor containing 2,000 tubes has a capacity of
approximately 18,000 tons (16,000 mt) of product per year. Sasol II will
produce 1.7 million tons (1.5 million mt) per year. The fluid bed reactor
does not have such size limitations and can be confidently scaled up using
well known technology. Since the objective of Sasol II Is to produce motor
fuel, only fluid bed reactors will be installed. Sasol II will contain
seven fluid bed reactors. More motor fuel per ton (0.9 mt) of coal will be
produced by Sasol II (1.78 barrels) than by Sasol I (1.26 barrels) since a
smaller amount of other products (waxes, heavy hydrocarbons) will be pro-
duced at Sasol II.
The synthesis flow scheme for Sasol II is similar to that for the fluid
bed reactors in Sasol I with the sequence of operations the same but the
29
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details of auxiliary processes different. In addition, product recovery
and refining are markedly different from Sasol I. In designing these
operations, advantage has been taken of the experience gained at Sasol I
and the most modern techniques of gaseous and liquid hydrocarbon process-
Ing.
At Sasol I, after cooling of the product gas, most of the non-condensed
hydrocarbon products are recovered In an oil-wash system and the tall gas
1s used for pipeline gas or reformed back to hydrogen and carbon monoxide.
Recovery of ethylene Is low with most remaining 1n the tall gas. A low
temperature Rectlsol wash 1s used to remove carbon dioxide from the re-
cycled synthesis tall gas. In the Sasol II plant, a more efficient hot
potassium carbonate absorption will be used for removal of carbon dioxide.
Also, the oil-wash system will be replaced by a low temperature unit which
recovers as separate streams a light oil, a propane/butane stream, an
ethane/ethylene stream, a stream of approximately 90% methane and a hy-
drogen rich stream. The ethane/ethylene fraction goes to an ethylene plant
where the ethylene Is recovered and the ethane recycled and cracked pro-
ducing additional ethylene. The hydrogen rich stream Is recycled to the
Synthol reactors or 1s used for refinery operations. Part of the methane
Is used as Internal fuel gas for the plant complex but the major portion
Is reformed by partial oxidation to hydrogen and carbon monoxide for recycle.
The product refinery 1s geared to the South African market which
requires mainly motor fuels, the majority In the gasoline range. The
light oleflns are combined by polymerization and the polymer product will
be partly hydrogenated to limit the final olefin content In the gasoline.
The above 400°F (200°C) material will be cracked to produce dlesel oil and
some gasoline fractions. The gasoline components will be blended to regular
and premium gasoline. Sasol II will produce the equivalent of a 40,000
barrel per day crude oil refinery.
Sasol II will be situated upstream of the large populated Ultwater-
srand area. The plant 1s being designed for maximum re-use of water within
the plant and zero discharge to local drainage systems. The two main
30
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sources of effluent are gasification which produces an aqueous liquor and
Flscher-Tropsch synthesis which produces a watery effluent containing
soluble oxygenates and organic acids. The aqueous liquor 1s first treated
1n a Phenosolvan plant where by extraction with 1sopropylether the water
soluble phenols are recovered as a crude tar add fraction and amnonla Is
stripped off the liquor and further purified by absorption. The Flscher-
Tropsch reaction water Is stripped of Its non-acid chemicals which are
recovered as marketable products such as ethanol, propanol, and acetone.
The remaining effluent, containing organic acids, and the stripped aqueous
liquor are then biologically treated In activated sludge units and further
purified by 1on exchangers and activated carbon to a purity where they can
be used as cooling water make up. A purge stream from the cooling water
system 1s used for hydraulic ash transport to the ash dewaterlng unit.
The ash dewaterlng unit 1s an evaporative system Involving a lined slimes
dam and an ash dump. Total water Input to the plant to replace losses
and evaporation 1s In the range of 14,000 to 15,000 gallons per minute
(3200 to 3400 m /h). Gaseous effluents must conform to South African codes.
Power plant stacks will be about 500 feet (150 m) high for dispersion of
boiler flue gas and Stretford process emission.
Sasol II 1s scheduled for completion early In 1980. As soon as Sasol
II Is finished construction will start nearby on Sasol III. The decision
to build Sasol II was made 1n 1979 after the new government 1n Iran
decided to cut off oil supplies to South Africa. Iran had been South
Africa's principle supplier. In order to save time and design costs,
Sasol III will be almost an exact copy of Sasol II and will cost $3.8
billion. Once the three plants are 1n operation, they will produce about
112,000 barrels of oil per day, approximately half of South Africa's
needs 1n the 1980's. The three Sasol plants will decrease South Africa's
dependence on Imported oil; they will strengthen the base of the South
African motor fuels and chemical Industry; they will make a significant
contribution to the saving of foreign exchange; they will provide a large
number of job opportunities not only 1n the plants themselves but also 1n
all the supporting services and Industries for all groups of the South
African community; and they will set a new standard 1n general for the coal
conversion Industry which can be considered as a target for second genera-
tion processes to Improve upon.
31
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5. Conclusions
The economic conditions for an oil-front-coal plant differ from country
to country especially since the viability and degree of risk depend so much
on non-technical factors such as government policy toward such a venture.
The making of synthetic oil from coal works In South Africa because of a
unique combination of factors Including the availability of vast reserves
of low cost coal, the scarcity of domestic petroleum resources, and the
abundance of cheap labor. South Africa has coal reserves of 25 billion
tons (23 billion mt). Almost 802 of South Africa's energy needs are met
by utilizing coal. South Africa Is boycotted by most of OPEC and 1s
without oil reserves of Its own. Therefore, South Africa has utilized
technologies Invented 1n Europe and the United States to convert Us
abundant coal resources to the forms of fuels and petrochemicals required
by a highly technical society.
The United States has seven times the coal reserves of South Africa
and a diminishing supply of domestic petroleum resources. Recent develop-
ments 1n the worldwide energy situation, especially the systematic OPEC
price Increases, have caused many Americans to express Interest In Sasol-
type coal-to-oll projects. There are, however, doubts about the economic
feasibility of a Sasol-like plant for the United States. Comparisons are
difficult because of the number of factors Involved Including the cost of
coal, construction, and labor. It has been estimated that oil could not
be produced from coal 1n the United States for less than $27 per barrel
and perhaps as much as $45, compared with around $20 per barrel currently
charged by OPEC. In addition, there are doubts about the complexity and
high capital costs Involved 1n scaling up such a process to meet American
needs. South Africa 1s currently spending between six and seven billion
dollars to Increase Its synthetic oil production to 112,000 barrels per
day. This would be a drop 1n the oil bucket 1n the United States which
uses 17.6 million barrels per day. Considering South Africa's gross
national product and energy consumption, Its effort 1s comparable to a
$300 billion crash program for the United States.
32
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Sasol's success Indicates that producing synthetic fuels from coal
can be technically and economically feasible. The technology 1s available
and the Sasol process - coal gasification plus Fischer-Tropsch synthesis -
1s the only commercially proven process that will produce synthetic fuels
quickly, on schedule, and at predictable costs.
33
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6. References
1. Fluor Technical Dept., "Coal Liquefaction Technology", SFR-103.
2. Fo1s1e, Jack, "S. Africa Holds Lead 1n Making 011 From Coal", Los
Angeles Times, July 30, 1979.
3. Hoogendoorn, J.C., "Gas from Coal for Synthesis of Hydrocarbons",
Ninth Synthetic Pipeline Gas Symposium, Chicago, October 31 -
November 2, 1977.
4. Hoogendoorn, J.C., "The Sasol Story", American Institute of Mining,
Metallurgical and Petroleum Engineers, 23rd Annual Meeting, Dallas,
February 24, 1974.
5. Klrk-Othmer, "Carbon Monoxide - Hydrogen Reactions", Encyclopedia
of Chemical Technology, 2nd Ed., Vol. 4, pp. 468 - 477.
6. Kronseder, John G., "Sasol II: South Africa's 011-from-Coal Plant",
Hydrocarbon Processing, July 1976, p. 56F.
7. Mclver, Alan E., "Sasol: Processing Coal Into Fuels and Chemicals
for the South African Coal, 011 and Gas Corporation", Second Annual
Symposium on Coal Gasification, Liquefaction, and Utilization, Best
Prospects for Commercialization, Pittsburgh, August 5-7, 1975.
8. "011 from Coal - How South Africa's Sasol Coal Conversion Plant
Operates", World Coal, April 1975, pp. 18-19.
9. Rudolph, Paul F.H., "Coal Gasification - A Key for Coal Conversion",
American Institute of Mining, Metallurgical and Petroleum Engineers,
23rd Annual Meeting, Dallas, February 24, 1974.
34
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6. References (Cont'd)
10. "South Africa Details Its Second Sasol Project", Coal Age, February
1975. pp. 82-93.
11• "Synfuel Success: Alchemy 1n South Africa", Time, August 20, 1979,
P. 42.
12. "Synthetic Chemicals 1n South Africa", Science, August 17, 1979,
p. 649.
35
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1 REPORT NO. 2.
EPA- 600/8-80-002
4. TITLE ANDSUBTITLE
SASOL: South Africa's Oil from Coal Story— Back-
ground for Environmental Assessment
7. AUTHOR(S)
J.L. Anastasi
9. PERFORMING ORGANIZATION NAME AND ADDRESS
TRW Environmental Engineering Division
One Space Park
Redondo Beach, California 90278
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
3. RECIPIENT'S ACCESSION NO.
6. REPORT DATE
Januarv 1980
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
10. PROGRAM ELEMENT NO.
INE825
11. CONTRACT/GRANT NO.
68-02-2635
13. TYPE OF REPORT AND PERIOD COVERED
Final; 7-8/79
14. SPONSORING AGENCY CODE
EPA/600/13
,B. SUPPLEMENTARY NOTES IERL.RTp project officer is William J. Rhodes , Mail Drop 61,
919/541-2851.
. ABSTRACT
report describes the world's only oil-from-coal plant, known as
SASOL, operated by South Africa since 1955. When almost $1 billion worth of expan-
sion is completed in the early 1980s, three SASOL plants will produce a total of
112,000 barrels of oil per day, or about half of South Africa's needs. Production
costs average Sl7 per barrel, well below the 1979 OPEC price of more than #20 per
barrel. South African motorists pay about #2.40/gallon (#0. 63/liter) of gasoline at
the pump. SASOL converts coal to liquid fuels in two steps: (1) the coal is gasified
with oxygen and steam under pressure to yield a mixture of reactive gases, and (2)
after being cleaned of impurities , the mixture is passed over an iron-based cata-
lyst in Fischer-Tropsch synthesis units to produce liquid fuels. SASOL's operation
is helped by South Africa's abundance of cheap labor and low cost coal. The U.S. ,
like South Africa, has vast coal reserves. Although comparisons are difficult, it has
been estimated that oil could not be produced from coal in the U. S. for less than
gf27 per barrel and perhaps as much as $45. The South African system is the only
commercially proven process for the production of synthetic liquid fuels. The report
provides some of the background on a process that will receive high priority for
environmental assessment.
17. KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
Pollution
Coal
Coal Gasification
Liquefaction
18. DISTRIBUTION STATEMENT
Release to Public
b.lDENTIFIERS/OPEN ENDED TERMS
Pollution Control
Stationary Sources
SASOL Process
19. SECURITY CLASS (This Report}
Unclassified
20. SECURITY CLASS (This page)
Unclassified
c. COSATI Field/Group
13B
08G
13H
07D
21. NO. OF PAGES
39
22. PRICE
EPA form 2220-1 (»-73)
36
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