1931. ------. [KOPPERS, H., G. m. b. H.] [Synthesis Gas.] German Patent Appl. K 163,511, no date (Cl. V-24 e). Auszüge deut. Patent-Anmeldungen, vol. 9, p. 302.

Pulverized fuel in a fluidized state is gasified with O₂ and steam while being heated with purge gas in such a way that the powdered fuel is passed into the reaction zone along with O₂ before it has made contact with the purge gas-steam mixture, and is there contacted with the highly preheated mixture of endothermic reacting gasification agents such as steam and CO₂. The use of a highly heated recycle gas stream decreases the O₂ consumption and through the creation of turbulent conditions increases the conversion.