1244. ---------------. [GREAT BRITAIN FUEL RESEARCH BOARD.] Synthesis of Methane. 5th Annual Rept., 1943-44, pp. 13-25; Gas Abs., vol. 1, No. 7, 1945, p. 10.

1244. ---------------. [GREAT BRITAIN FUEL RESEARCH BOARD.] Synthesis of Methane. 5^th Annual Rept., 1943-44, pp. 13-25; Gas Abs., vol. 1, No. 7, 1945, p. 10.

Problem of the synthesis of CH₄ from CO and H₂ by means of promoted Ni catalysts at 350°-800° C. and at pressures 1-50 atm. has been investigated separately by the Gas Research Board Laboratories and the Fuel Research Station in Britain. Both laboratories have studied methods to prevent (a) the loss of activity of the catalyst due to overheating, which causes a diminution of active surface (sintering) and (b) deposition of C at higher temperatures. Their suggested means of overcoming these difficulties are in fairly close agreement: (1) Catalysts prepared by the precipitation of nitrates with alkali as carbonate in the presence of kieselguhr support, followed by a very thorough washing, are more resistant to heat treatment and give a much lower C deposition than those obtained by impregnation, that is, ignition of the absorbed nitrates on the support. (2) Overheating, or sintering, as well as the rate of C deposition, depends on the effective removal of the exothermic heat of reaction and increases with increasing working temperatures. At 700° C. the life of the catalyst becomes relatively short. However, at 800° C. an extremely long life was observed in spite of sintering, probably because at such high temperature the reaction is no longer dependent upon specially active atoms in the catalyst. (3) The rate of C deposition depends upon the nature of the support. Catalysts of identical composition supported on kieselguhr from 1 source gave 10 times more C deposition than those on kieselguhr from another source. (4) C deposition decreases as the size of the catalyst granules increases. Heat dissipation is also favored by the use of a narrow catalyst space surrounded by a jacket containing a high-boiling liquid. (5) The admixture of steam with the process gas decreases C deposition, and 15% steam (by volume) entirely prevents it. (6) The higher the H₂:CO ratio the less the tendency to deposition of C. The amount of steam required by gases of various H₂:CO ratio in preventing C deposition is shown by curves for various temperatures 350°-600° C.