(371aq) Studies of sCO2 Power Cycles for Sustainability

Using Second-Law analysis, various equipment configurations of the Allam power cycle have been explored. This cycle uses oxy-fuel combustion of natural gas into high-pressure, high-purity supercritical CO₂ that can be used as an alternative working fluid as well as for direct sequestration or subsequent reaction to valuable products. All the variations show higher thermodynamic efficiency in power generation than conventional natural-gas combined cycles (NGCC) with only small efficiency differences among them. All configurations have the largest lost work in the combustor and heat economizers (recuperators). We also find that improved Allam cycle efficiency sacrifices short-term profitability due to costly changes in equipment and conditions. Therefore, we investigate the outcomes of life-cycle analyses (LCA), including processes that utilize product CO₂ for synthesis, to determine if economic sacrifice may not be necessary for reduced carbon emission.