1793.  ------. [KALBACH, J. C.] (Hydrocarbon Research, Inc.). Fuel Gases of High Heating Value. United States Patent 2,623,816, Dec. 30, 1952. Chem. Abs., vol. 47, 1953, p. 2965.

Coal in fluidized form is carbonized by a current of hot gases from the gasification of the residual coke in a second stage by using O₂ and steam. The mixed gases from the carbonizing chamber are passed through a cyclone to remove fly ash, and then to a converter containing finely divided C. The pressure in the converter is 150-450 p. s. i., and the temperature is 1,000º-1,350º F. Methanation proceeds rapidly in the absence of a catalyst. The C in the converter is maintained in a fluidized state and is supplemented by the C from cracking hydrocarbons in the gas supplied to it. Entrained C is caught by a cyclone collector and returned to the converter. Excess C formed in the converter is returned to the gasification zone. The process is self-sufficient in its heat and energy requirements, even supplying that required for the intial compression of the O₂.