A thermodynamic analysis of a Biomass Integrated Gasification Combined Cycle (BIGCC) plant has been
performed based on energy and exergy balances in a proposed configuration. Combustion of supplementary
biomass fuel is considered using the oxygen available in the gas turbine (GT) exhaust. The
effects of pressure and temperature ratios of the GT system and the amount of fuel burned in the
supplementary firing chamber on the thermal and exergetic efficiencies of the plant have been investigated.
The plant efficiencies increase with the increase in both pressure and temperature ratios;
however, the latter has a stronger influence than the former. Supplementary firing of biomass increases
the plant efficiencies of a BIGCC plant till an optimum level of degree of firing. The other technical issues
related to supplementary firing, like ash fusion in the furnace and exhaust heat loss maintaining
a minimum pinch point temperature difference are accounted and finally a set of optimum plant
operating parameters have been identified. The performance of a 50 MWe plant has been analyzed with
the optimum operating parameters to find out equipment rating and biomass feed rates. Exergetic
efficiencies of different plant equipments are evaluated to localize the major thermodynamic irreversibilities
in the plant.