1946. In Britain, Alfred August Aicher obtained several patents for improvements to the process in the 1930s and 1940s. Aicher's company was named Synthetic Oils Ltd (not related to a company of the same name in Canada). Around the 1930s and 1940s, Arthur Imhausen developed and implemented an industrial process for producing edible fats from these synthetic oils through oxidation. The products were fractionally distilled and the edible fats were obtained from the - fraction which were reacted with glycerol such as that synthesized from propylene. "Coal butter" margarine made from synthetic oils was found to be nutritious and of agreeable taste, and it was incorporated into diets contributing as much as 700 calories per day. The process required at least 60 kg of coal per kg of synthetic butter. Commercialization Ras Laffan, Qatar The LTFT facility Pearl GTL at Ras Laffan, Qatar, is the second largest FT plant in the world after Sasol's Secunda plant in South Africa. It uses cobalt catalysts at 230 °C, converting natural gas to petroleum liquids at a rate of , with additional production of of oil equivalent in natural gas liquids and ethane. Another plant in Ras Laffan, called Oryx GTL, has been commissioned in 2007 with a capacity of . The plant utilizes the Sasol slurry phase distillate process, which uses a cobalt catalyst. Oryx GTL is a joint venture between QatarEnergy and Sasol. Sasol The world's largest scale implementation of Fischer–Tropsch technology is a series of plants operated by Sasol in South Africa, a country with large coal reserves, but little oil. With a capacity of 165 000 Bpd at its Secunda plant. The first commercial plant opened in 1952. Sasol uses coal and natural gas as feedstocks and produces a variety of synthetic petroleum products, including most of the country's diesel fuel. PetroSA PetroSA, another South African company, operates a refinery with a 36,000 barrels a day plant that completed semi-commercial demonstration in 2011, paving the way to begin commercial preparation. The technology can be used to convert natural gas, biomass or coal into synthetic fuels. Shell middle distillate synthesis One of the largest implementations of Fischer–Tropsch technology is in Bintulu, Malaysia. This Shell facility converts natural gas into low-sulfur Diesel fuels and food-grade wax. The scale is . Velocys Construction is underway for Velocys' commercial reference plant incorporating its microchannel Fischer–Tropsch technology; ENVIA Energy's Oklahoma City GTL project being