METHOD OF MAKING OXYGEN-FREE GAS FROM OXYGEN-CONTAINING GAS

摘要

An oxygen-containing gas (e.g. air) is passed (from conduit 6) into an oxygen-removal fluidized bed (in space 1) of particles including particles containing reactive CaS. The rate of oxygen supply relative to the reactive CaS content of the oxygen removal bed is less than the stoichiometric amount required for the highly exothermic oxidation of all CaS to CaSO4, and the temperature of the oxygen-removal bed is maintained below the temperature at which CaS is oxidized to CaO + SO2 by passing an oxygen-containing gas (e.g. air) through a heat-transfer coil immersed in the oxygen-removal bed. Particles are transferred from the oxygen-removal bed (via port 3) to an oxidation bed (space 7) fluidized by heated oxygen-containing gas from the heat-transfer coil whereby the remaining CaS is exothermically oxidized to CaSO4. The CaSO4 of the hot particles is endothermically reduced to CaS by a fuel in a fluidized reducing bed (space 8) and the resulting CaS-containing particles are transferred to the oxygen-removal bed (space 1) for further use.