GB505151A - Process of and apparatus for the low temperature distillation of coal, lignite, shale or similar solid carbonaceous fuels - Google Patents

Abstract

505,151. Low - temperature carbonization. V.H.A. SYNDICATE, Ltd., and HOESTEMBERGHE, C. VAN. Aug. 12, 1938, No. 23834. [Classes 51 (ii) and 56 (i)] In the low-temperature distillation of solid carbonaceous fuel wherein the fuel is passed in the form of a shallow layer over the heated sole plates 5, 6 of preheating and distillation zones 1, 2 respectively on which it is subjected to a zigzag ploughing and propelling movement, the fuel is increasingly heated progressively but non-uniformly by combustion gases flowing mainly in co-current thereto which heat the distillation zone indirectly and the preheating zone firstly indirectly and then directly, the heating being finally increased prior to discharge of the fuel to cause fusion of the particles thereof. The fuel is conveyed through the zones by conveyers 7, 8 each comprising a belt 10, Fig. 4, carried by a pair of chains 9, and the belts are provided with lateral rows of scraper blades 11 and also regulator rakes 13. The latter comprise flat blades at rightangles to the belt and occupy a quarter of a lateral row and are staggered from one row to the next. The remainder of a row is occupied by the scrapers 11 which comprise ploughshares, Fig. 5, of alternate inclination in alternate rows. The scrapers may be shaped as arrow-heads. The blades 13 carry along fuel left by the scrapers ; both the blades and scrapers are of sufficient height to avoid submersion by the intumescent fuel. The preheating and distillation chambers have their sole plates heated by flues 3 and 4 which are supplied with combustion gases from a furnace 21 within the setting, dampers 23 and 31 controlling the heating respectively. The flue 4 communicates with the furnace through longitudinal flues 29 and vents 30 ; the gases from the flue 4 discharge into lateral flues 32 and mix with the directly supplied combustion gas to the flue 3 in a mixing flue 33 to which air may also be supplied through a valve 24. Ports 38, 39 allow the combustion gas to enter the preheating chamber for direct heating. The final more intense heating is effected by auxiliary burners 22 arranged at the discharge end of the distillation chamber ; a maximum temperature of 600‹ C. is reached, although 380-420‹ C. is preferred. The heating of the distillation chamber may be increased by replacing its refractory roof by metal plates 34 covered by a variable thickness of sand; also by side flues interconnected by transverse-flues. The gases of distillation are removed through an offtake 26 placed between the bands of the conveyer 8. The fuel to be carbonized is preferably comminuted to a grain size of 0 to 10 millimetros.