00/00446 Comparison between IGCC and supercritical power plant processes

Abstract

In recent years great deal of research work has been done to improve the efficiency of coal fired power plants. There are principally two different ways to increase the efficiency. The first is to increase the steam parameters in a conventional steam process and the other is to develop combined cycles for coal based on integrated gasification combined cycle (IGCC) or pressurized fluidized bed (PFBC) technology. For supercritical processes, the parameters of interest are turbine inlet pressure and temperature. Parameters that must be optimized are the number of reheaters, reheat pressure and temperature, the number of feed water preheaters and extraction pressure. In this work the future possibilities of supercritical and IGCC processes were studied. Both supercritical and IGCC processor were optimized by using a PROcess SIMulation program (PROSIM). Parameter values for both cases were chosen to meet future expectations that will be achieved by improving steam and gas turbines and as well as boiler materials. Results showed that the net plant efficiency is increased by raising the inlet steam temperatures and pressures in a supercritical process, also gas turbine expander inlet temperature and pressure ratio in an IGCC process. In order to reach efficiencies over 50 %, the processmore » parameter values must be increased beyond what is possible today. Interesting result has been obtained by increasing the gasification temperature in the IGCC process. The net plant efficiency decreased if the process used Cold Gas Clean Up, but increased if Hot Gas Clean up was used.« less