Coal-to-oil is an indirect coal liquefaction technology, which produces synthetic gas through coal gasification and then produces synthetic oil through Fischer-Tropsch synthesis. The method of "indirect coal liquefaction" was industrialized in South Africa as early as 1960. South Africa is also a country rich in coal and short of oil. Its coal reserves are as high as 55.333 billion tons, and the reserve-production ratio is 247 years. Coal accounts for 75.6% of its primary energy. Since 1955, South Africa has used coal gasification technology and Fischer-Tropsch synthesis technology to produce petroleum and chemical products such as gasoline, kerosene, diesel oil, synthetic wax, ammonia, ethylene, propylene and α-olefin. South Africa's Fischer-Tropsch synthesis technology has developed a modern slurry bed reactor for alcohol synthesis. At present, Sasol Company has two sets of "indirect coal liquefaction" devices, which produce more than 7 million tons of liquid hydrocarbon products every year (320,000 tons of Sasol and 6.75 million tons of Saiku), including 5 million tons of synthetic oil products and 49.5 million tons of coal consumption every year. The accumulated investment of $7 billion has been recovered. Now the annual output value reaches 4 billion US dollars, and the annual profit is nearly1200 million US dollars. Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences has started the research and engineering development of indirect liquefaction technology of iron-based and cobalt-based catalyst Fischer-Tropsch synthetic oil since 1980s, and has completed the industrial experiment of coal-based synthetic oil with a scale of 2000 tons/year, and 5 tons of coal can be synthesized into 1 ton of refined oil. According to the project plan, in the next three years, Shanxi, a major coal province in China, is expected to build a 10,000-ton "coal-to-oil" plant. The Chinese Academy of Sciences also envisages that by 2008, a million-ton coal-based synthetic oil enterprise will be built, and a large-scale coal "refinery" will be built between several large coalfields in Datong and Shuozhou areas of Shanxi. Recently, the project of Shuozhou Lianshun Energy Company with an annual output of 5 million tons of coal-based synthetic oil with a total investment of 654.38+0 billion US dollars has entered the substantive development stage and is scheduled to be completed and put into operation in 2005. Products will include nearly 500 chemical extension products such as synthetic gasoline and synthetic diesel with octane number not less than 90 and no sulfur and nitrogen.