THERMODYNAMIC PERFORMANCE ANALYSIS AND ECONOMIC EVALUATION OF EXTERNALLY FIRED GAS TURBINE CYCLES FOR SMALL SCALE BIOMASS COGENERATION

摘要

Externally fired gas turbine (EFGT) cycles in combination with a biomass-fueled, atmospheric circulating fluidized bed (CFB) furnace are investigated for small scale production of power and district heat. Both closed and open gas turbine cycle configurations are considered. The thermodynamic performance analysis includes an evaluation of cycle-to-furnace heat matching and cycle-side pressure loss considerations. An economic analysis is presented for the various EFGT configurations, and comparisons are made with existing and emerging alternatives for small-scale biomass cogeneration. Simulation results show that thermodynamic performance varies between the different configurations and working fluids, with electric efficiencies in the range of 31-38% (LHV) and total efficiencies of 86-106% (LHV). An economic evaluation for an 8 MW{sub}f plant shows that the specific capital cost is about 3200-3900 USD/kW{sub}e for a first commercial plant. The turbomachinery and the CFB furnace dominate the total plant cost, with each contributing about 1/3 of the total installed equipment cost. The cost of electricity, COE, is estimated to be 73-84 USD/MWh{sub}e for 4000 full load hours per year in a cogeneration application.