567. ------. [DUFFIELD, F. L.] Production of Water Gas. British Patent 570,007. June 19. 1945: appl. filed Sept. 20. 1943. British Chem. Abs., 1945. B. I. P. 354: Chem. Abs., vol. 40, 1946, p. 4498.

Patent Abstracts

In the process of water gas low in CO and of necessity high in CO₂ (eliminated later by scrubbing), the reaction of C+H₂O=CO+H₂-28,900 gm. cal. takes place above 1,000º, with 99% decomposition of the H₂O, whereas C+2 H₂O=CO₂+2 H₂-18,900 gm. cal. occurs at about 600º, and only 5% of the H₂O is composed. The % decomposition of H₂O is increased (in the latter reaction) by rising the pressure of operation and superheating the steam so that it supplies nearly all the endothermic heat, and the steam flow can continue for a long period. An example of running conditions is: 4 units of steam at 20 atm. and 1,160º provide enough heat to decompose 1 unit of steam at the coke-bed temperature of 760º: the resulting gas comprises H₂, 65%, CO, 8% and CO₂, 27% and is already at a pressure at which elimination of CO₃ is simple. The coke is raised to the necessary temperature by a producer gas run, and that gas is burned in regenerators, which superheat the steam. The excessive superheat at the beginning of a steam flow is reduced by admixture of saturated steam in reduced proportion as the flow proceeds.