Synthetic fuel is the Bergius process. In this process, coal is liquefied by heating in the presence of hydrogen gas (hydrogenation). Dry coal is mixed with heavy oil recycled from the process. Catalysts are typically added to the mixture. The reaction occurs at between to and 20 to 70 MPa hydrogen pressure. The reaction can be summarized as follows: formula_1 After World War I several plants were built in Germany; these plants were extensively used during World War II to supply Germany with fuel and lubricants. The Kohleoel Process, developed in Germany by Ruhrkohle and VEBA, was used in the demonstration plant
Synthetic fuel synthetic ammonia, and nitric acid. Nearly one third of the Bergius production was produced by plants in Pölitz () and Leuna, with 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). By early 1944, German synthetic fuel production had reached more than from 25 plants, including 10 in the