GB947726A - Improvements in processes and apparatus for the carbonization of coal - Google Patents

Abstract

An apparatus for carbonizing coal, e.g. briquetted brown coal, comprises means 3 for preheating the coal to between 200 DEG C. and 300 DEG C., and a vertical shaft retort 1 in which hot gases are circulated in a plurality of successive heating zones 9 . . . 16, each maintained at a higher temperature than the preceding zone, and means for controlling the gas circulation in each zone whereby the temperature range in each zone may be separately controlled. The apparatus is in four stages: preheating stage 3, low temperature carbonization (250 DEG C. to 550 DEG C.) stage 4, high temperature carbonization (550 DEG to 1000 DEG C.) stage 5, and a cooling stage 33, and stages 3 . . . 5 are divided into zones 6 . . . 8, 9 . . . 11, 12 . . . 16 respectively. A gas-tight partition 20 separates the stages 3, 4 and is provided with periodically operated doors. In a modification, Fig. 2 (not shown), the stages 3, 4 are in separate containers inter-connected <PICT:0947726/C3/1> by a closed conveyer. Temperate control is effected by mixing heated and cooled gases in chambers 22 before delivery to the various zones, the gases being circulated by blowers 40. In addition, combustion chambers 24, fed with air by a blower 41, are utilized in the higher temperature part of the apparatus, hot gas being delivered at 34 to pass in succession through radiant heaters 17 in stage 5, and to manifolds 27 having outlets 28, Fig. 12, in stage 4. A condenser 19 is included in the outlets 43 from zone 9, and a heat exchanger 35 in the circuit of the cooling stage 33. In a second modification, Fig. 3 (not shown), the zone 6 is omitted and the radiant heaters 17 are replaced by manifolds which supply hot gas to the coal, as in stage 4, the zones 12 . . . 16 being compressed into one zone only. In this embodiment, high temperature carbonization is carried out at 700 DEG to 850 DEG C.