The incorporation of Sasol
South Africa has large deposits of coal, which had low commercial value due to its high fly ash content. If this coal could be used to produce synthetic oil, petrol, and diesel fuel, it perhaps would have significant benefit to South Africa. In the 1920s, South African scientists started looking at the possibility of using coal as a source of liquid fuels. This work was pioneered by P. N. Lategan, working for the Transvaal Coal Owners Association. He completed his doctoral thesis from the Imperial College of Science in London on The Low-Temperature Carbonisation of South African Coal.
In 1927, a white paper from the government was issued describing various oil-from-coal processes being used overseas and their potential for South Africa. In the 1930s, a young scientist named Etienne Rousseau obtained a Master of Science from the University of Stellenbosch. His thesis was entitled "The Sulfur Content of Coals and Oil Shales." Rousseau became Sasol's first managing director.
After World War II, Anglovaal bought the rights to a method of using the Fischer–Tropsch process patented by M. W. Kellogg Limited, and in 1950, Sasol was formally incorporated as the South African Coal, Oil, and Gas Corporation (from the Afrikaans of which the present name is derived: Suid-Afrikaanse Steenkool-, Olie- en Gas Maatskappy), a state-owned company.
Commissioning of the Sasol 1 site for the production of synfuels started in 1954. Construction of the Sasol 2 site was completed in 1980, with the Sasol 3 site coming on stream in 1982. The Zevenfontein farm house served as Sasol's first offices and is still in existence today.[11][12]
Coal mining
To support the required economies of scale for coal-to-liquids (CTL) process to be economical and competitive with crude oil, all stages of the operations, from coal mining to the Fischer–Tropsch process and product work up must be run with great efficiency. Due to the complexity of the Lurgi gasifers used, the quality of the coal was paramount. The initial annual output from the Sigma underground mine in Sasolburg was two million tons. Annual coal production from this mine peaked in 1991 at 7.4 million tons.[11]
Today, most of the gasifiers in Sasolburg have been replaced with autothermal reformers that feed natural gas piped from Mozambique. Natural gas generates about 40–60% less carbon dioxide for the same energy produced as coal, thus is significantly more environmentally friendly. Gas-to-liquids technology converts natural gas, predominantly methane to liquid fuels.[11][12]
Today, Sasol mines more than 40 million tons (Mt)[13]
Fischer–Tropsch reactor technology
The initial reactors from Kellogg and Lurgi gasifiers were tricky and expensive to operate. The original reactor design in 1955 was a circulating fluidised bed reactor (CFBR) with a capacity of about 1,500 barrels per day. Sasol improved these reactors to eventually yield about 6,500 barrels per day. The CFBR design involves moving the whole catalyst bed around the reactor, which is energy intensive and not efficient as most of the catalyst is not in the reaction zone. Sasol then developed fixed fluidized bed (FFB) reactors in which the catalyst particles were held in a fixed reaction zone.
This resulted in a significant increase in reactor capacities. For example, the first FFB reactors commercialised in 1990 (5 m diameter) had a capacity of about 3,000 barrels per day, while the design in 2000 (10.7 m diameter) had a capacity of 20,000 barrels per day. Further advancements in reactor engineering have resulted on the development and commercialisation of Sasol Slurry Phase Distillate (SSPD) reactors which are the cornerstone of Sasol's first-of-a-kind GTL plant in Qatar.[11][12]
From fuels to chemicals
The fuel price is directly linked to the oil price, so is subject to potentially large fluctuations. With Sasol only producing fuels, this meant that its profitability was largely governed by external macroeconomic forces over which it had no control. In order to become less susceptible to oil price changes, they diversified to chemicals co-produced in the Fischer–Tropsch process.
In the 1960s ammonia, styrene, and butadiene became the first chemical intermediates sold by Sasol. The ammonia was then used to make fertilizers. By 1964, Sasol was a major player in the nitrogenous fertilizer market. This product range was further extended in the 1980s to include both phosphate- and potassium-based fertilizers. Sasol now sells an extensive range of fertilizers and explosives to local and international markets, and is a world leader in its low-density ammonium nitrate technology.[18]
With the extraction of chemicals from its Fischer–Tropsch product slate coupled with downstream functionalization and on-purpose chemical production facilities, Sasol moved from being just a South African fuels company to become an international integrated energy and chemicals company with over 200 chemical products being sold worldwide. Some of the main products produced are diesel, petrol (gasoline), naphtha, kerosene (jet fuel), liquid petroleum gas (LPG), olefins, alcohols, polymers, solvents, surfactants (detergent alcohols and oil-field chemicals), co-monomers, ammonia
Recent developments
In May 2025, Sasol's CEO spoke about the company's plans to source more renewables and offset the use of coal feedstock. In the same year, Sasol was the world’s top producer of synthetic fuel from coal, and South Africa's -second-largest emitter of greenhouse gases. Sasol maintains a target of reducing emissions by 30% by 2030, and intends to expand its renewable energy target by around two thirds to, 2,000 megawatts in total.[20]
