A New Dry Process for Simultaneous Removal of SO2 and NO from Flue Gas by Powder-particle Fluidized Bed.

Abstract

A new process, which is a combination of dry processes for flue gas desulfurization and selective catalytic reduction of NOx with NH3 for simultaneous removal of SOx and NOx from the flue gas, was developed using a powder-particle fluidized bed. In the process, SOx was removed by fine sorbent, and NOx was reduced to N2 with NH3 catalyzed by coarse DeNOx catalyst in a powder-particle fluidized bed reactor. The powder-particle fluidized bed was made of a stainless steel tube of 0.053m internal diameter and 1.0m in height above the distributor. Three kinds of fine sorbents, iron oxide dust (a by-product of steel production), sodium-based sorbents (sodium bicarbonate and sodium carbonate), and copper-based sorbents (CuO, CuO•V2O5/Al2O3, and CuO•V2O5•K2SO4/Al2O3), were evaluated in this study. Coarse particles of inactive silica sand and DeNOx catalysts of WO3/TiO2 and V2O5•WO3/TiO2 were used as fluidized medium particles. The effects of various operating conditions and properties of DeSOx sorbent and DeNOx catalyst on removal of SO2 and NO were investigated. The iron oxide dust appeared to be a potential low-cost sorbent for removal of SOx and also a catalyst for reduction of NOx. Both sodium-based and copper-based sorbents had sufficient reactivity for removal of SO2. The powder-particle fluidized bed reactor was effective for simultaneous removal of SOx and NOx from the flue gas. In the proposed process, the simultaneous removal of over 90% of SO2 and NO was achieved by proper combination of fine sorbent and coarse catalyst.