Selection of SO2 Sorbents for Simultaneous Removal of SO2 and NO in the Powder-particle Fluidized Bed.

Abstract

Several kinds of SO2 sorbents or catalysts have been evaluated in a process for simultaneous removal of SO2 and NO from flue gas using a powder-particle fluidized bed. In the process, SO2 was captured by fine sorbents and NO was reduced with NH3 catalyzed by a coarse DeNOx catalyst or by both coarse and fine catalysts. Experiments were carried out in a laboratory scale powder-particle fluidized bed reactor of 1.0m in length above the distributor, 0.053m inside diameter, in a temperature range from 373 to 873K. Several kinds of fine sorbents including sodium aluminate, manganese oxide, copper oxide, sodium bicarbonate, and copper oxide supported on alumina with addition of vanadium oxide (CuO•V2O5/Al2O3) were tested in this study. The coarse particles of inactive silica sand and active DeNOx catalysts of WO3/TiO2 and V2O5•WO3/TiO2 were used as fluidized medium particles. The SO2 and NO removal efficiencies by using fine sorbents and coarse catalysts were investigated under the following conditions: static bed height of 0.3m, superficial gas velocity of 0.5m/s, and inlet concentrations of SO2 and NO of 500ppm. Experimental results suggested that CuO•V2O5/Al2O3, sodium aluminate, and sodium bicarbonate were suitable as SO2 sorbents. In a typical temperature range (573-673K) of flue gas, the SO2 removal achieved was 60-70% for CuO•V2O5/Al2O3 at Cu/S mole ratio of 1, about 55% and 40-65% at Na/S mole ratio of 3 for sodium aluminate and sodium bicarbonate. The NO removal approached nearly to 100% at NH3/NO mole ratio of 1 in the active temperature range of the DeNOx catalyst.