GB851443A - Method of treating gases derived from the distillation of coal - Google Patents

Abstract

851,443. Purifying coal gas. METALLGESELLSCHAFT A.G. April 10, 1957, No. 11801/57. Class 55 (2). In a method of treating coal gas to remove partly or wholly, all or some of the impurities contained therein the gas is treated catalytically without an addition of oxygen, treated, if necessary, by scrubbing with alkaline inorganic and/or organic liquids to remove hydrogen sulphide and carbon dioxide, preferably under pressure, and subjected to pressure and low temperatures to effect separation of constituents of the gas and/or treated to remove lighter hydrocarbons by scrubbing or treatment with active carbon, the catalytic treatment being effected by passing the gas over a sulphurresistant hydrogenation catalyst at a temperature between 50‹ and 500‹ C., preferably between 150‹ and 450‹ C., and at a pressure of at least 5 atmospheres and for the purpose of converting into innocuous substances impurities such as nitrogen oxides, oxygen, hydrogen cyanide, acetylene and/or similar unsaturated hydrocarbons contained in the gas. The catalyst may be a molybdenum or cobalt-molybdenum catalyst, such as are for example described in Specification 766,625, [Group III]. The catalytic treatment may be effected with the catalyst in a fixed or a fluidised bed and the gas for treatment may be heated by heat exchange with the hot treated gas. The conversion of the impurities may be effected in more than one catalytic stage. The space velocity in the catalytic treatment may be between 1000 and 15,000 parts by volume of gas per part by volume of catalyst per hour. The gas may be cooled and freed of tar and ammonia before the catalytic treatment and removal of lighter hydrocarbons may be before or after the catalytic treatment. Scrubbing to remove hydrogen sulphide when necessary is effected after the catalytic treatment.