A thermodynamic analysis of a biogas-fired integrated gasification steam injected gas turbine (BIG/STIG) plant

A thermodynamic analysis considering both the first and the second laws of thermodynamics has been made on a 53 MW (net) biogas-fired integrated gasification steam injected gas turbine (BIG/STIG) plant. The energy utilization diagrams (EUDs) for the plant and for the reaction subsystems have also been considered, revealing both problems and potentials for improvement. The analysis indicates a thermal efficiency of about 41% (power based) and 45% (power and recovered heat based) but that the exergy loss in the combustion chamber is largest at about 79% of the total system exergy loss.