A regenerable sorbent injection/filtration process for H_2S removal from hot gas

摘要

The operational characteristics of a hot gas desulfurization process involving regenerable sorbent injection and its subsequent collection with a ceramic filtration device were studied utilizing a bench-scale transport reactor.Hydrogen sulfide removal from simulated hot gas was evaluated as a function of both zinc oxidebased sorbent physical and chemical characteristics and various process parameters.In addition,the sorbent capture efficiency and regenerability of the ceramic filtration device were evaluated,and regeneration of sulfided sorbents via injection into an oxidizing gas was studied.For both sorbent sulfidation and within layers sorbent regeneration,gas-solid reaction occurred both in the duct and within layers of partially reacted sorbent captured by the ceramic filter.Very high sulfur removal efficiencies were obtained only in highly reducing hot gas compositions at or above about 700 deg C, using stoichiometric ratio (defined as ZnO/H_2S ratio) values of about 1.5,and sorbent particles of about 20 #um#m or less in diameter.Under such conditions,the experimental data indicated that reaction of H_2S with zinc vapor formed by reduction of zinc oxide contributed appreciably to sulfur removal.Negligible zinc loss from the hot zone of the reactor was detected,apparently due to rapid formation of zinc sulfide product layers on zinc oxide particles.The ceramic filtration devices captured 100