The Linde–Frank–Caro process is a method for hydrogen production by removing hydrogen and carbon dioxide from water gas by condensation.^[1][2] The process was invented in 1909 by Adolf Frank and developed with Carl von Linde and Heinrich Caro.^[3]

Water gas is compressed to 20 bar and pumped into the Linde–Frank–Caro reactor. A water column removes most of the carbon dioxide and sulfur. Tubes with caustic soda then remove the remaining carbon dioxide, sulphur, and water from the gas stream. The gas enters a chamber and is cooled to −190 °C, resulting in the condensation of most of the gas to a liquid. The remaining gas is pumped to the next vessel where the nitrogen is liquefied by cooling to −205 °C, resulting in hydrogen gas as an end product.

• Water gas shift reaction
• Timeline of hydrogen technologies
• Frank–Caro process, another process used to produce cyanamide from calcium carbide and nitrogen gas in an electric furnace