Patent GB-478215-A (GB)
Title: Improvements in treating gases, and apparatus therefor
IPC: C10K3/00
Filed: 1936-07-20
Abstract: 478,215. Gas - purifying processes. RESEARCH CORPORATION. July 20,1936, No. 20051. Convention date, Aug. 14, 1935. [Classes 51 (i) and 55 (ii)] In a heat-treatment of gases, e.g. for the decomposition of a constituent, or molecular re-arrangement or oxidation and applied to the destenching of noxious gases, the decomposition of resin-forming constituents in town's gas &c., part of a body of gas-traversable, heat-absorbing refractory material which may include catalysts, is heated to create a thermal alteration zone contiguous with another less hot zone and the gas is forced through the body in one direction thus causing the hot zone to move in the same direction, the flow being periodically reversed to reciprocate the zone within the body and the size of the particles of the refractory material being so regulated that a close approach to thermodynamic reversability of heat exchange is effected with a small fall in the gas pressure. Air &c. may be mixed with the gases in treatments involving hightemperature oxidation, Apparatus for destenching gases from fish-scrap driers comprises two beds 3, 4 of heat-absorbing material on grids 5, 6 providing three gas spaces 7, 8, 9. Fuel gas is first admitted at valve 24 with air from fan 28 and burns in space 8, combustion products discharging through a valve 33. When a destenching temperature, e.g. 1500‹ F., is reached, valve 33 is closed and valves 16, 17 in piping leading to a chimney 20 are opened so that the products discharge through both beds and create a destenching zone in each. The fuel and air valves and valve 16 are then closed and the fuel gases at 200‹ F. admitted by a blower 30 through a valve 18, traversing both beds downwardly and discharging through valve 17. When the effluent gas temperature rises, valves 17, 18 are closed and valves 19, 16 opened so that the gas passes upwardly through the beds until the exhaust gas temperature begins to rise, whereupon the sequence is repeated. To compensate for heat losses, a small amount of fuel gas may be continuously burnt in space 8. After some time the hot zone tends to spread over the whole of the beds and to overcome this heat may be removed from the middle of the hot zone. Valves 16, 17 are closed and a valve 34 is opened so that the foul gases descend bed 3 and ascend bed 4, being withdrawn from the central space 8 through an economizer or further heat-absorbing bed 38. When the zone has been reduced in size, to restore the maximum heat in its centre the supply of fuel gas through valve 24 is increased and combustion air is caused to pass through bed 38 by closing a valve 27 and opening a valve 45. Alternatively, heat may be removed from both ends of the zone to limit its size. In a modification, two hopper-bottomed chambers are connected by a conduit above a pebble bed in each. In both embodiments, layers of relatively large pieces of refractory material may intervene between the beds in place of the open spaces bounding them. A third arrangement provides a single chamber having a bed of material initially heated by the combustion of fuel above it, the gas to be treated being passed alternately downwardly and upwardly through the bed. Specifications 377,996 and 390,849 are referred to.