Performance Modeling of Integrated Chemical Looping Air Separation and IGCC with CO₂ Capture

Abstract

A new power cycle system composed of chemical looping air separation (CLAS) and integrated gasification combined cycle (IGCC) with CO2 capture and storage (CCS) is presented and analyzed. Key issues of the CLAS-IGCC–CCS system and corresponding solutions are proposed and explained in this work. A conceptual CLAS-IGCC–CCS system is set up, and its performance is modeled and validated. In the CLAS-IGCC–CCS system, the CLAS subsystem is used to supply O2 for the coal gasification in the IGCC subsystem, and Mn2O3/Mn3O4 is selected as the suitable oxygen carrier. The temperature of the reduction reactor (TRR) should be kept at 850 °C to obtain high cold gas efficiency (CGE) and high system efficiency (SE). The oxygen to coal mass ratio (OTCR) and the water to coal mass ratio (WTCR) should be kept around 0.7 and 0.06, respectively, to achieve high CGE and SE. The clean syngas from the coal gasification process then burns with air in the gas turbine combustor. The heat recovery boiler with three-pressure reheat is chosen to recover the waste heat from the gas turbine. Chemisorption using monoethanolamine (MEA) is used for CO2 capture in the CCS subsystem. With the optimized parameters, the CGE of 82.55% and the SE of 46.22% can be reached for the CLAS-IGCC–CCS system.