H2S Removal by Fine Limestone Particles in a Powder−Particle Fluidized Bed

Abstract

An efficient dry desulfurization process for hot coal gas was proposed. The process uses a powder-particle fluidized bed as the reactor, in which coarse particles of several hundred micrometers are fluidized via hot gas consisting of H2S, H2, and N2 while fine limestone particles are fed continuously into the bed. Fine limestone particles of less than 30 μm were used as H2S sorbent. The effects of operating parameters on the H2S removal efficiency were investigated. Desulfurization via 5-μm limestone was very effective, demonstrating over 90% H2S removal at 1073 K for the case of Ca/S = 2, even under the conditions of a very short residence time (0.3 s) of gas in the bed. Investigation of the sorbent pore structure before and after calcination and desulfurization revealed the correspondence of higher specific surface area of CaO to higher H2S removal efficiency.