ANALYSIS OF A FIXED-BED GASIFIER IGCC CONFIGURATION

Integrated coal gasification combined cycle (IGCC) systems offer substantial advantages for power generation. This paper analyzes a proposed configuration in which regeneration gases from a zinc ferrite based, fixed-bed, hot-gas desulfurization system are recycled to a fixed-bed gasifier for capture and disposal of the sulfur by a calcium-containing material (e.g., limestone) added to the coal. The minimum required sulfur capture in the gasifier for technical feasibility is analyzed and compared to test results from a 1.05-m-i.d., fixed-bed gasifier. Other integration issues involving zinc ferrite regeneration requirements and system operability are also discussed. This study concluded that the proposed system is less attractive than originally thought, primarily due to the low sulfur capture efficiency of a fixed-bed gasifier, the uncertain composition of the bottom ash, and the regeneration characteristics of zinc ferrite in a fixed-bed reactor.