Coal liquefaction (Coal To Liquid) is a chemical process that transforms solid particles of coal into gaseous or liquid hydrocarbons. In addition to the Fischer-Tropsch process, the Bergius-Pier process is a means to achieve this - it converts carbon particles with the addition of hydrogen at a process pressure of 150 to 700 bar.
Due to high energy prices, the Bergius-Pier process represents an economic alternative to extracted oil and natural gas. The finely ground coal can be converted using special high-pressure plunger pumps. At high pressure, hydrogen at a temperature of about 500 degrees Celsius reacts with the coal mash. High pressure pumps deliver the mash to the plant's liquefaction reactor. As the mixture is extremely abrasive, special pumps are required to meet the demands of coal liquefaction.