GB470275A - Improvements in the production of gas from carbonaceous fuels - Google Patents

Abstract

470,275. Coking processes; retort furnaces. LEWIN, E. G. (Didier-Werke Akt.-Ges.) Feb. 14, 1936, No. 4562. [Classes 51 (ii) and 55 (i)] Gas mixtures containing hydrogen and carbon monoxide in proportions suitable for use in chemical processes, for example, destructive hydrogenation, are obtained in continuously operating externally heated vertical retorts in which the time of contact of the reacting gases with the fuel is controlled by varying the position at which the gases are withdrawn. The fuel passes through a pre-heating zone before distillation, and reaction zones, and finally a water gas zone below the gas offtake, and the temperature in the reaction zone may be separately controlled. Superheated steam may be introduced into the coal before it enters the high temperature region, to increase the reaction-promoting power of the carbonized residue, the quantity of carbon dioxide in the reaction zone being reduced by removal through an outlet near the top of the retort. The coal first enters a preheating chamber 1 before reaching a gasefying chamber 2, comprising distilling, reaction, and water gas zones, and a cooling zone 3, the chamber 2 being heated by flues 6 supplied with preheated gas and air from passages 7 and 8. Waste gases pass through ducts 10 to a recuperator 11 in which the gas and air are heated, and pass out through flues 12 and main 13. Upper and lower gas offtakes 15, 14 are provided with dampers, so that either may be closed to control the length of the path of the gases through the charge. Secondary burners 18 may be used to supply more heat to the reaction zone, the walls of the retort in this region 19 being made of silicon carbide. Steam from inlets 20, 21 increase the reactivity of the fuel, and a gas offtake 22 serves to remove any desired amount of carbon dioxide from the early stages. A partition 23 provides for the vertical descent of the charge. Flues 24 around the preheating chamber 1 are fed with hot waste gases. The sensible heat in the outgoing gases is used to preheat the gas and air for use in the heating lines by passage through a heat-exchanger 31 in counter-flow to the gas admitted from the main 32, as described in Specification 464,000. Steam is admitted to the water gas zone through inlets 34, the water gas mixing with the distillates before withdrawal. Reference has been directed by the Comptroller to Specification 106,189, [Class 55 (i)].