Exergetic Comparison of Two KRW-Based IGCC Power Plants

Abstract

In studies supported by the U.S. Department of Energy and the Electric Power Research Institute, several design configurations of Kellogg-Rust-Westinghouse (KRW)-based Integrated Gasification-Combined-Cycle (IGCC) power plants were developed. Two of these configurations are compared here from the exergetic viewpoint. The first design configuration (case 1) uses an air-blown KRW gasifier and hot gas cleanup while the second configuration (reference case) uses an oxygen-blown KRW gasifier and cold gas cleanup. Each case uses two General Electric MS7001F advanced combustion turbines. The exergetic comparison identifies the causes of performance difference between the two cases: differences in the exergy destruction of the gasification system, the gas turbine system, and the gas cooling process, as well as differences in the exergy loss accompanying the solids to disposal stream. The potential for using (a) oxygen-blown versus air-blown-KRW gasifiers, and (b) hot gas versus cold gas cleanup processes was evaluated. The results indicate that, among the available options, an oxygen-blown KRW gasifier using in-bed desulfurization combined with an optimized hot gas cleanup process has the largest potential for providing performance improvements.