GB673648A - Improvements in or relating to the conversion of finely divided solid carbonaceous material into gas mixtures - Google Patents

Abstract

673,648. Gasifying powdered carbonaceous material. DIRECTIE VAN DE STAATSMIJNEN IN LIMBURG. Jan. 8, 1949 (Jan. 8, 1948], No. 608/49. Class 55 (i). In gasifying fire-grained coal, coke, coal slime, sawdust, &c., preheated to about the gasification temperature, gases at a higher temperature, comprising mainly carbon dioxide and steam are introduced into the bottom of a zone with boundaries diverging upwardly into which the fuel is admitted in concurrent or counter-current flow, the velocity of the com. bustion gas at the inlet being adjusted to be less than that required to keep the larger fuel particles in suspension but to be sufficient, though progressively falling off, to carry the finest particles upwardly until gasification is completed. Fuel of grain size up to 10mm. passes from an electrically-heated dryer 3 into a preheater 9 supplied with products from a combustion chamber 5 in which gas from pipe 8 is burnt with air or oxygen, steam or carbon dioxide being added. Products from a chamber 11 similarly supplied with gases enter the base of a conical producer 10 and mix with the stream from the preheater in a throat 10a. Fuel and gases may also be introduced through inlets 15, 16, water spray at points 17 and catalysts at 18. The product gases pass through a separator 21, heat exchanger 24, and gas turbine 26. A series of superposed horizontal plates may be mounted in the lower part of the producer which is waisted between each pair of plates the effect being to cause larger particles to disintegrate, and inlets preferably at the narrowed portions may introduce fuel and gases radially or tangentially upwardly or downwardly. In another arrangement the fuel is admitted at the top. Part of the gases generated may be taken off at one or more points and returned to a preheating combustion chamber and the heat of the remainder recovered in heat-exchangers. A second producer may be employed from which molten clinker is removed. The CO : H 2 ratio in the final gas which may be 1 : 1 if oxygen is initially employed, may be adjusted by introducing steam or water into the producer at one or more points, together with catalysts facilitating the conversion to carbon dioxide and hydrogen. Further formation may similarly be increased. Gasification may be effected under superatmospheric pressure, e.g. 3 atmospheres, and the gas supply to producer and preheating combustion chamber , caused to pulsate.