Environmental Assessment of Gas Turbine/Steam Turbine Combined Cycles

Abstract

The environmental aspects of the conceptual base-load, combined gas-steam turbine power plants designed by General Electric and Westinghouse in Phase II of the Energy Conversion Alternatives Study (ECAS) were analyzed. Each contractor had developed a combined cycle design which incorporated an integrated coal gasifier producing low-heat-content fuel gas, as well as a design fueled by coal-derived liquid purchased from an off-site producer. The conceptual power plants each produced some 60 to 900 MWe (gross), employing gas turbine inlet temperatures of 1600–1900 K. Equilibrium combustion gas properties were calculated for each system, and kinetic calculations were made for NOx production. The systems burning gaseous fuel were estimated to meet NOx emission standards. Neither design which used liquid fuel was estimated to meet NOx standards because of the high nitrogen content of the coal-derived synthetic liquid fuel.

Environmental Assessment of Gas Turbine/Steam Turbine Combined Cycles

“…Each of the four conceptual power plant designs considered in this study, including projected specialized hardware, is described in detail in the source references (3,4,6). Particular features of each design have been reviewed critically by NASA (8) or have been treated in the course of our study (1).…”

“…Thus, interstage heat removal in the combustor is one means of controlling thermal NO x generation. Details of the models and assumptions used in the calculations to estimate species distributions for each of the combustion modifications listed above are given in the source report (1).…”