3699.     WILKINS, E. T., AND JOLLEY, L. J.  Catalytic Production of Methane.  Coke and Gas, vol. 9, 1947, p. 245.

        Paper presented at the 11th International Congress of Pure and Applied Chemistry, London, July 1947.  The work of the British Fuel Research Station is reviewed.  The process has reached such a perfected stage that no obstacle appears to stand in the way of building a full-scale plant whenever desired.  The cost of synthetic CH4 production is made up largely of the cost of making the necessary water gas.  Catalysts of Ni, ThO2, MgO, all supported on kieselguhr, have been used to promote the reaction.  4 primary difficulties have been met.  (1) C deposition on the catalyst.  Methods for prevention are:  To add steam to the reaction gases; to increase the H2:CO ratio of the gases; to select a catalyst least susceptible to C deposition; and to study the correct design of the reaction vessel.  (2) Sintering of the catalyst.  This can be avoided by keeping the actual temperature of the catalyst below 600░ C.  The actual temperature is found to be about 150░ below that of the temperature as measured.  (3) Poisoning by S.  This is the greatest single cause of catalyst deterioration and occurs when the Ni has absorbed a 2-3% of S by weight.  It can be avoided by using a gas of extreme purity, but it is preferred to use a cheaper method of using a gas of moderate purity (below 0.03 grain S per 100 cu. ft.) and secure a moderate catalyst life of 3 months.  The above purity is secured by use of the well-known Fe2O3ĚNa2CO3 mixture at 200░.  (4) Dissipation of the heat of reaction.  This is secured by watercooling the shell of the reaction vessel to 200░.  The catalyst is arranged to line the wall of the vertical tube, the outside of which is water cooled.