Coal gasification combined-cycle system analysis. Final report

Abstract

This report summarizes the results of the second phase of a study involving combustion turbine power plants using coal gasification. The study concentrated on systems integration and the optimization of power plant conceptual designs. In order of importance, the objectives of the study were to: (1) determine potential levels of thermal efficiency for well integrated gasified coal combined cycle (GCC) systems employing current technology combustion turbines and near-commercial, oxygen-blown Texaco gasifiers. (2) Quantify the effects of varying key design parameters of various components on overall plant performance. (3) Project potential levels of performance made possible by using advanced, combustion turbines and advanced gasifiers in well-integrated gasification power plants. To meet these objectives emphasis was placed on effective waste heat management and practicality in synthesizing overall power plant arrangements. Evaluations were confined to thermodynamic analysis and did not include equipment cost estimation. Current technology systems were defined which yielded thermal efficiencies in the range of 35 to 37%. It was found that approximately one percentage point in thermal efficiency could be realized by using either the British Gas Corporation (BGC) slagging, fixed-bed gasifier or the air-blown Texaco gasifier in place of the oxygen-blown Texaco gasifier. Two percentage points were gained bymore » increasing the gas turbine combustor exit temperature about 300/sup 0/F. These results suggest the possibility of approaching 40% in practical future power plants. Cost-effective configurations with such performance levels are expected to offer a more than competitive alternative to conventional coal-fired steam power plants equipped to meet emission standards.« less