GB1447546A - Gasification of carbonaceous materials - Google Patents

Abstract

1447546 Pyrolysis of carbonaceous materials OCCIDENTAL PETROLEUM CORP 14 Sept 1973 [28 Sept 1972] 43380/73 Heading C5E Particulate carbonaceous material 10 is passed through a first pyrolysis zone 22 in a turbulent stream of conveying gas 18 and heated, e.g. at 675-900‹ C. for 0À01-3 seconds by a particulate solid heat carrier to produce a gaseous pyrolysis product which contains C 1-4 hydrocarbons, the pyrolysis products are cooled at 26 to prevent appreciable thermal decomposition of the gaseous hydrocarbons, separated at 27 into gaseous products 28 and solids 34, the solids 34 are introduced into a second pyrolysis zone 38 in a turbulent stream of conveying gas and heated, e.g. to 760-980‹ C., by a particulate solid heat carrier to generate carbon monoxide and hydrogen. A portion of the CO + H 2 product of the second zone can be recycled to the two zones 22 and 38 as the hot conveying gas. As shown, in the treatment of a bituminous coal 10, steam 21 and 47 can be introduced into the pyrolysis reactors 22 and 38 and a portion 62 of the solid product 52 from the zone 38 is subjected to partial combustion at 68 to produce hot char which is recycled as the stream 76 to the pyrolysis reactors. Liquids 80 are separated from the gaseous products 32 and 56 from the two pyrolysis reactors and recycled as the stream 88, after removal of thermally stable components 86, e.g. benzene. The gas 82 is combined with a CO 2 +CO+H 2 stream 120 produced by reacting hot char with hot steam in the synthesis vessel 116, e.g. 815-1370‹ C. and 300-600 p.s.i.g. The combined stream is hydrogenated at 94 at 315-510‹ C. and 50-150 p.s.i.g. using a cobalt molybdate catalyst to react propylene, ethylene and butylene with hydrogen contained in the stream. The hydrogenated gas is subjected to a shift reaction at 96 at 315-510‹ C. and 50-100 p.s.i.g. using a chromium-promoted iron oxide catalyst. H 2 S and CO 2 are removed at 104 and 106 and any hydrocarbons having 5 or more carbon atoms are removed by adsorption with activated carbon at 110. The gas is then heated at 112 to 260-480‹ C. and subjected to methanation at 128 to convert carbon monoxide to methane and steam using a nickel catalyst such as Raney nickel. Water is removed from the gas at 140 after cooling at 136 to 27-50‹ C. and compression at 138 to 900-1100 p.s.i.g. The product gas 134 is interchangeable with natural gas and typically contains 95% by volume of methane, 3À7% ethane and 1À3% hydrogen.