Study of thermodynamic performance of an integrated gasification combined cycle power plant

Computational analysis is performed to investigate the effects of the pressure ratio of the gas cycle (R-p) and the temperature ratio across the combustion chamber (R-T) on the thermodynamic performance of an integrated gasification combined cycle (IGCC) power plant with single pressure power generation for both the gas and steam cycles. The gases are assumed to be real ones that follow the Redlich-Kwong equation of state. The overall efficiency of the cycle (eta) is found to be maximum at an optimum pressure ratio of the gas cycle for a given temperature ratio. The second law analysis indicates that maximum exergy is destroyed in the process of gasification and is not at all affected by the temperature ratio, while the effect of the pressure ratio on it is also not very significant. The exergy loss in the combustor is found to decrease with an increase in either of the ratios. For the heat recovery steam generator (HRSG), it increases with a higher temperature ratio and decreases with a higher pressure ratio. The total exergy loss of the cycle is found to decrease with either of these two ratios while the other is held constant.