Exergoeconomic study of gas turbine steam injection and combined power cycles using fog inlet cooling and biomass fuel

Abstract

Biomass energy has the potential to replace fossil fuels despite its lower heat value. Fog cooling and steam injection, as well as adding steam turbine cycles to gas turbine cycles, can enhance the performance of power generation systems. Here, the results are reported of energy, exergy and exergoeconomic analyses of two proposed biomass (wood) integrated steam injection cycles and combined power cycles. Their performances are assessed for similar sets of conditions. The thermodynamic analyses demonstrate that at lower values of compressor pressure ratio the combined cycle has a higher thermodynamic efficiency but at higher values of pressure ratio the steam injection plant is advantageous. For the same conditions, the steam injection plant exhibits a higher net power output. The exergoeconomic analyses show that electricity and component costs for the combined cycle are higher than for the steam injection plant. Also fog cooling is more influential on the thermodynamic performance of the BIFCC than the BIFSG plant and at compressor pressure ratios of 20 and 26 and higher, respectively, for the BIFCC and BIFSG plants, fog cooling is economic. The exergy loss rate and its cost are higher for the combined cycle at all pressure ratios.