Thermodynamic Analysis of CO2 Capture Cycles Using Pre-Combustion Decarbonization and Membrane Technologies

Abstract

Over the past 5–10 years, interest has increased significantly in CO2 free power generation cycles. This study focuses on precombustion decarbonization cycles that reform syngas, separating the CO2 using a membrane, and then burning hydrogen-rich fuel in a gas turbine. The syngas reforming section is comprised of 1) Auto-thermal reformer (ATR) used for syngas production 2) water gas shift reactor (WGSR) to shift CO into CO2 3) CO2 -separation membrane and 4) combustion with hydrogen rich fuel. Overall performance shows an efficiency loss of 8.4% and 10.6% compared to the baseline cycle for the high and low temperature CO2 membrane cycles examined. The operating temperatures of the membranes are limited by the exothermic CO shift reaction favoring lower temperatures. Furthermore, a chemical exergy analysis of the reformers in the decarbonization system is undertaken to understand the impact of fuel reforming.