Screening Evaluation of Novel Power Cycles Integrated with Gasification Plants. Final Report

摘要

This report presents the results of a screening study on power cycles integrated with a coal gasification plant. Three basic plant configurations are studied: (1) the Condensing Combined Cycle, the most common combined cycle, which includes combustion turbines, gas expanders and condensing steam turbines. This configuration should be considered as the base case; (2) the Single Cycle, which is comprised of combustion turbines and gas expanders, but no steam turbines; (3) the Non-Condensing Combined Cycle, which utilizes combustion turbines, gas expanders and a non-condensing steam turbine. The gasifier used throughout is the Texaco entrained, coal slurry-fed, air blown gasification system along with a scrubber, sulfur removal system and a tail gas treater. The combustion turbines are advanced types. Nominal turbine inlet temperature in all cases is 2400 exp 0 F but pressure ratios vary depending upon the particular example. The turbine cooling method is thermal barrier, and both air and steam cooling is applied. Performance and water requirements are compared among the various cycles. The results show that efficient power plants integrated with a coal gasification system are possible and do not necessarily require the condensing steam turbine that is characteristic of combined cycle systems. The most efficient plant configuration studied included a non-condensing steam turbine. The best plant heat rate calculated for this configuration is 7956 Btu/Kwh which compares very favorably to the 8287 Btu/Kwh calculated for the condensing combined cycle. The best system that did not include steam turbines yielded a heat rate of 8039 Btu/Kwh. (ERA citation 04:040790)