Within the European Union, demonstration size coal gasification combined cycle power generation systems are either being designed, built or operated, e.g. a 340 MWe plant at Puertollano, Spain. For such advanced power generation systems there is a need to remove sulfides from the fuel gas. Existing technologies to remove these pollutants are based on wet gas cleaning system which have an adverse effect on cycle efficiency, can have high capital cost and can produc an aqueous effluent requiring expensive treatment before disposal. The development and introduction of hot gas cleaning systems offers the potnetial of a lower cost approach to pollutant control with associated cycle efficiency advantages. External and regenerable sorbent bed processes have been developed for the removal of sulfides in the gasification cycles for two main reasons: Firstly, the use of in-bed or injected sorbents for gas desulfurization in coal gasification is not well developed and, secondly, the use of a fuel gas in fuel cell power generation systems requires high gaseous sulfur purity requirements. External sorbent bed processes are therefore intended for use in both bulk sulfur capture and as a final "polishing" stage for the removal of residual concentrations of sulfides.
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