GB1471598A - Apparatus and method for carrying out reactions in a fluidised bed - Google Patents

Abstract

1471598 Rotary fluidised bed apparatus NATIONAL RESEARCH DEVELOPMENT CORP 25 July 1975 [30 April 1974] 18855/74 Heading B1F [Also in Division F4] Fluidised bed apparatus comprises a rotatable drum having a permeable circumferential wall against which the bed is supported in operation and through which the fluidising gas passes. Apparatus for the combustion of a lean air/gas mixture e.g. the exhaust air from a drying oven, comprises a drum 19 rotatable about a vertical axis and having an inner wall 21 of perforated metal supported by an apertured outer wall 22. The drum is supported within a housing 10 rotated by a drive 23, 24 and having an inlet stem 16 sealed into a stationary chamber 26 fed with the air/gas mixture. The top of the housing is closed except for an outlet 38 above which a lipped funnel feed trap 39 is mounted. The bed 20 comprises particles of two size ranges, the finer particles forming the bed as the apparatus is started, and being heated by the combustion of the mixture and auxiliary fuel fed from a nozzle 29 into the feed stem above the seal 27. When the fine particles of the bed reach a sufficiently high temperature, the rate of supply of gases used, the speed of rotation is increased, and the coarser particles form the bed, while the fine particles are collected in the lip of the trap at 41. Copper wool 33 forms a flame trap between the housing 10 and the drum 19. The use of the rotating bed support and coarser particles allows a very high feed rate of the gas/air mixture. The fine particles used for start up may be withdrawn and collected, coarse particles being fed to the bed from a hopper (Fig. 2), or passages from the lip area of the trap may allow circulation of the bed particles (Fig. 3). Solid fuel may be burned or gasified in a fluidised bed in a cylinder 50 rotating about a horizontal axis within a stationary housing 52, Fig. 4. The pulverluent fuel is delivered through a stationary shaft 53 to a shoot 70 directed towards the circumferential wall. A fan 62, separately driven, projects through the open end of the stationary housing, and auxiliary fuel gas may be supplied through a ring pipe 74. The outlet may be stationary and formed of coolant pipes, or may include a trap for finer particles and rotate with the drum 50. Heavy oil may be churned in a bed of inert particles, and lighter oil may be sprayed on to the outside of the drum 50. Inert particles from the bed may be recirculated through a heat exchanger (Fig. 5). The perforations in the wall of the drum may direct the fluidising gases tangentially.