1764. ---------------. [KING, J. G.] Work of the Gas Research Board. Report of the Director. Synthesis of Methane. Gas Research Board Pub. 8; Gas Jour., 1944, pp. 623-624, 660-661, 689, 691; Gas World, vol. 120, 1944, p. 6245; vol. 121, 1944, p. 18; Chem. Abs., vol. 38, 1944, p. 4775.

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Literature Abstracts

In experiments on the synthesis of CH₄, with a granular Ni catalyst and with passage of the gas at atmospheric pressure, a low reaction temperature (350°-500°) led to loss of catalyst activity and deposition of C, as the result of the development of a high surface temperature where the reaction gases first come into contact with the catalyst. The rate of loss of activity is increased by a decrease in the ratio H₂:CO; in practice it may be necessary to employ a ratio above 1.2. The addition of steam counteracts the tendency to form C from the CO and also under certain circumstances prevents the loss of catalyst activity caused by sintering. The surface temperature also can be controlled by recirculation and by use of a shaped or rod catalyst arranged to lose heat rapidly by radiation. By use of these expedients it is possible to operate the simple Ni catalyst at any temperature within the range 350°-800° and at any pressure within the range 1-50 atm. In the synthesis from water gas with high H₂:CO ratios the most suitable catalyst for work at a relatively low temperature is Ni promoted by ThO₂ and supported on kieselguhr. The S in the gas is kept below 0.1 grain per 100 cu. ft. by using an Fe oxide-Na₂CO₃ contact material at 180°-230°. With purified water gas, the catalyst life was 77 days, during which time the CH₄ content of the CO₂-free gas varied from 80 down to 30% with an average of 65%. In order to prevent undue deposition of C, the H₂:CO ratio must be kept above 1.5. Other factors affecting the formation of C are the rise in temperature of the catalyst, its size, and a rise in pressure above atmospheric. The gas should be passed downward through the catalyst. Under these conditions and with an exit temperature of 350°, the process gas can be treated at the rate of 3,700 vol. per vol. of catalyst per hr. Difficulties were encountered in developing these results to a semi-scale apparatus possessing 5,000 cu. ft. of gas per day.