Integrated gasification combined cycle with carbon dioxide capture by elevated temperature pressure swing adsorption

Abstract

This paper investigates the CO2 capture energy consumption via elevated-temperature pressure swing adsorption (ET-PSA) for CO2/H2 separation. IGCC power plants with ET-PSA, with the conventional Selexol process and without CO2 capture are built in Aspen Plus. The CO2 capture energy consumption of ET-PSA is evaluated by the specific primary energy consumption for CO2 avoided (SPECCA), which is a function of the net electrical efficiency and the specific CO2 emission rate. The ET-PSA unit with different processes simulated in gPROMS is coupled into the IGCC model, the operation parameters of which are analyzed to achieve the lowest SPECCA. The results show that the CO2 capture energy consumption has a tendency to decrease by increasing the adsorption time, the residence time, and the purge-to-feed ratio; reducing the purge ratio; and adding the CO2 reflux. The SPECCA of ET-PSA with the 5–3–1 process is 2.79MJ/kgCO2 with a 90.5% CO2 capture ratio, which is 11.71% lower than that of the Selexol process. An effective way to further reduce the SPECCA of ET-PSA is to add rinse and purge steps, whose energy loss mainly comes from the consumption of high-temperature steam. The calculated SPECCA of ET-PSA with rinse and purge steps is 2.32–2.52MJ/kgCO2, which is 20.3–26.6% lower than that of the Selexol process.