Thermo-economic assessment of biomass gasification-based power generation system consists of solid oxide fuel cell, supercritical carbon dioxide cycle and indirectly heated air turbine

Abstract

This study energetically, exergetically and economically analyses a hybrid electricity generation system. The proposed system is a combination of a biomass gasifier, a solid oxide fuel cell module, an indirectly heated air turbine and a supercritical carbon dioxide power cycle. Influences of major designing and operating plant parameters, viz. current density of the solid oxide fuel cell, pressure ratio of the air compressor, turbine inlet temperature of the CO2 gas turbine, on the performance of the proposed system have been examined. The proposed system exhibits the highest first law efficiency of 51% at the current density of 2000 A/m2 and cell temperature of 1123 K, air compressor pressure ratio of 4.4, CO2 gas turbine inlet pressure and temperature of 10.14 MPa and 423 K. At this aforesaid condition, the proposed system exhibits a second law efficiency of 45%. It is found that the highest amount (40.70%) of exergy destruction takes place at the biomass gasifier, followed by the solid oxide fuel cell (20.05%). The economic analysis predicts that the minimum achievable levelized unit cost of electricity is 0.095 $/kWh.