Simultaneous SO 2/NO x removal by a powder-particle fluidized bed

Abstract

Simultaneous dry removal of SO 2 and NO x from flue gas has been investigated using a powder-particle fluidized bed. In a process of flue gas desulfurization by use of solid sorbents such as FeO (dust from a steel plant) and CuO, the smaller the particle size of sorbents, the higher the expected SO 2 conversion. In a powder-particle fluidized bed (PPFB), fine particles less than 40 μm in diameter fed into the bed are fluidized with coarse particles. But only the fine particles are entrained from the bed, and their residence time in the bed is remarkably long. The reduction of NO x with NH 3 in the fluidized bed is catalyzed by coarse particles or both coarse and fine particles. In this study, PPFB was applied to simultaneous dry SO 2/NO x removal process, and several kinds of sorbents or catalysts were evaluated in a PPFB. Using the selected sorbents and catalysts, kinetic measurements were made in the temperature range of 300 to 600°C. SO 2 removal efficiencies were affected by reaction temperature, sorbent/S ratio, and static bed height. NO x removal efficiencies in excess of 95% were achieved at NH 3/NO x mole ratio of 1.0. When FeO was used as sorbent, SO 2 conversion increased with increasing temperature and reached 80% at 600°C.