Parametric study of a hybrid one column air separation unit (ASU) and CO2 power cycle based on advanced exergy cost analysis results

In this study advanced exergy and exergoeconomic analyses are performed on the integrated cryogenic air separation unit (ASU), oxy-fuel carbon dioxide power cycle and LNG vaporization process. Advanced exergy results show that endogenous part of exergy destruction is more than exogenous part which means interactions between the process components is not significant. CR-4 compressor with 190,095 kW exogenous exergy destruction rate has the highest share of this type of exergy destruction among the process components. Advanced exergoeconomic analysis results show that interactions between the process components are weak. That is because of large values of endogenous part towards the exogenous part. Among investigated process components unavoidable exergy destruction cost rate of heat exchanger (H-1) and combustion chamber is higher than the avoidable part. Avoidable/endogenous exergy destruction cost rate of P-1, CR-1 and H-8 components is the highest and consequently these elements will have the highest priority for the optimization. The capital investment and operating and maintenance cost rate of pump (P-1) is 10,018 $/h. This value reveals that saving the money from the operating and maintenance costs will make up the replacement cost of this component with the high-tech ones. Based on the parametric analysis, the optimum design parameters of pump (P-1), compressor (CR-1) and heat exchanger (H-8) are ηis=82%, rp=6.195 and ΔTmin=2K, respectively.