Integration of Gas Switching Chemical Looping Technology in IGCC Power Plants for Inherent CO2 Capture

Abstract

Integrated Gasification Combined Cycles (IGCC) are promising power production systems from solid fuels due to their high efficiency and good environmental performance. Chemical Looping Combustion (CLC) is an effective route to reduce the energy penalty associated with CO2 capture. This concept comprises a metal oxygen carrier circulated between a reduction reactor, where syngas is combusted and an oxidation reactor, where O2 is withdrawn from an air stream. Parallel to CLC, oxygen carriers capable of releasing free O2 in the reduction reactor, i.e. Chemical Looping Oxygen Production (CLOP), have been developed. This offers interesting integration opportunities in IGCC plants, replacing energy demanding Air Separation Units (ASU) with CLOP. Gas switching (GS) reactor cluster technology consists of a set of reactors operating in reduction and oxidation stages alternatively, providing an averaged constant flow rate to the gas turbine and a CO2 stream readily available for purification, and avoiding transport of solids across reactors. In this work, a GS-CLOP-CLC power plant is studied and benchmarked against unabated IGCC and pre-combustion CO2 capture models. Additionally, an exergy analysis accurately assesses the loss distribution in the different power plant sections from a second law perspective, and new optimization opportunities are identified.