A new semi-dry desulfurization process using a powder-particle spouted bed

A new semi-dry desulfurization process was tested in this study. The process uses the so-called powder-particle spouted bed (PPSB) as the reactor in which coarse medium particles, usually silica sand of several hundred micrometers in size, are fluidized with hot flue gas. A slurry of fine SOx sorbent, such as slaked lime or other alkaline powder, is continuously supplied into the bed of coarse particles. As a consequence, both the desulfurization reaction and slurry drying take place simultaneously in the single reactor. By using a model flue gas, SO2-air, and the sorbent Ca(OH)(2) in a laboratory-scale reactor, the removal efficiency of this process was examined with respect to major operating parameters in this study. It was demonstrated that SO2 removal in excess of 95% can be achieved at Ca/S = 1.2, while spent sorbent appears in the form of dry powder. The optimal temperature of flue gas treated with this technique was shown to be approximately 420 K. In comparison with wet desulfurization scrubbers, this PPSB semi-dry process appears to have lower cost, less complicated configuration and simpler disposal of used sorbent. (C) 2000 Elsevier Science Ltd. All rights reserved.