| 摘要 |
1534645 Combustion or calcination in fluidized beds METALLGESELLSCHAFT AG 31 May 1977 [31 May 1976] 22989/77 Heading F4B An exothermic reaction, i.e. combustion or calcination of sulphur bearing ores, is carried out in a fluidized bed reactor under substantially stoichiometric conditions, the combustion air being fed to the bed in at least two streams entering the bed at different loads, solids taken from the bed are cooled in a second fluidized bed, air from the cooling bed being fed to the reactor as secondary air, and at least some of the solids are recycled to the bed to regulate the temperature. Part of the combustion air may be used as fluidizing gas, and the ratio of secondary air to fluidizing air is such that the fluidized bed substantially fills the reactor 1, solids removed from the exhaust gases by a cyclone 9 being returned directly to the reactor 1. Gases from the cyclone 9 pass through a waste heat boiler 2, electrostatic precipitator 3 and air preheater 4 to atmosphere, and solids taken from the bed in the reactor are fed at 11 to a multiple fluidized bed cooler 5, the cooled solids being fed to the bed at 15 or taken off at 16. The air heated in the cooler 5 is returned to the reactor at 8 together with air from the preheater 4 which also supplies fluidizing air at 7. Material is fed to the reactor through a liner 6 below the secondary air inlet by part of the preheated air. Steam may be produced in the cooler 5. Some of the solids withdrawn from the cooler may be used to cool the exhaust gases from the cyclone 9 before they are fed to the electrostatic precipitator. The Specification gives desirable values for the density of the fluidized bed above the secondary air inlet, the ratios of the volumes of fluidized gas to secondary gas supplied, and the position of the secondary air inlet in the reactor. |
