Also indirect coal conversion (where coal is gasified and then converted to synthetic fuels) was developed in Germany by Franz Fischer and Hans Tropsch in 1923. During World War II, Germany used synthetic oil manufacturing (German: Kohleverflüssigung) to produce substitute (Ersatz) oil products by using the Bergius process (from coal), the Fischer–Tropsch process (water gas), and other methods (Zeitz used the TTH and MTH processes). Before World War Two in 1931, the British Department of Scientific and Industrial Research located in Greenwich, England set up a small facility where hydrogen gas at extreme high pressure was combined with coal to make a synthetic fuel.
The Bergius process plants were the primary source of Nazi Germany's high-grade aviation gasoline and the source of most of its synthetic oil, 99% of its synthetic rubber and nearly all of its synthetic methanol, synthetic ammonia, and nitric acid. Nearly 1/3 of the Bergius production was produced by plants in Pölitz (Polish: Police) and Leuna, with more than 1/3 more in five other plants (Ludwigshafen had a much smaller Bergius plant which improved "gasoline quality by dehydrogenation" using the DHD process).
Synthetic fuel grades included "T.L. [jet] fuel ", "first quality aviation gasoline", "aviation base gasoline", and "gasoline - middle oil"; and "producer gas" and diesel were synthesized for fuel as well (e.g., converted armored tanks used producer gas).:4,s2 By early 1944, German synthetic fuel production had reached more than 124,000 barrels per day (19,700 m3/d) from 25 plants,[verification needed] including 10 in the Ruhr Area.:239 In 1937, the four central Germany lignite coal plants at Böhlen, Leuna, Magdeburg/Rothensee, and Zeitz, along with the Ruhr Area bituminous coal plant at Scholven/Buer, had produced 4.8 million barrels (760×10^3 m3) of fuel. Four new hydrogenation plants (German: Hydrierwerke) were subsequently erected at Bottrop-Welheim (which used "Bituminous coal tar pitch"), Gelsenkirchen (Nordstern), Pölitz, and, at 200,000 tons/yr Wesseling. Nordstern and Pölitz/Stettin used bituminous coal, as did the new Blechhammer plants. Heydebreck synthesized food oil, which was tested on concentration camp prisoners. The Geilenberg Special Staff was using 350,000 mostly foreign forced laborers to reconstruct the bombed synthetic oil plants,:210,224 and, in an emergency decentralization program, to build 7 underground hydrogenation plants for bombing protection (none were completed). (Planners had rejected an earlier such proposal because the war was to be won before the bunkers would be completed.) In July 1944, the 'Cuckoo' project underground synthetic oil plant (800,000 m2) was being "carved out of the Himmelsburg" North of the Mittelwerk, but the plant was unfinished at the end of WWII.
Indirect Fischer-Tropsch ("FT") technologies were brought to the US after World War 2, and a 7,000 barrels per day (1,100 m3/d) plant was designed by HRI, and built in Brownsville Texas. The plant represented the first commercial use of high-temperature Fischer Tropsch conversion. It operated from 1950 to 1955, when it was shut down when the price of oil dropped due to enhanced production and huge discoveries in the Middle East.
After World War Two, in 1949 a demonstration plant for converting coal to gasoline was built and operated by the U.S. Bureau of Mines in Louisiana, Missouri. Direct coal conversion plants were also developed in the US after WW2, including a 3 TPD plant in Lawrenceville, NJ, and a 250-600 TPD Plant in Catlettsburg, KY.