Process and Reactor Level Simulations of Coal-Direct Chemical-looping Combustion

Abstract

Reducing carbon emissions from fossil-fueled power plants has been an active area of research in recent years. One technology that appears to be very promising for high-efficiency low-cost carbon capture is chemical-looping combustion (CLC) (Leion et al. 2009a). CLC involves combustion of fuels (either gas or solid) by heterogeneous chemical reactions with an oxygen carrier, usually a particulate metal oxide. Because of the absence of air in the fuel reactor, the combustion products are not diluted by other gases (e.g., N₂), resulting in high purity of CO₂ available at the fuel reactor outlet. Also, the net energy release from a CLC process is theoretically identical to that from conventional combustion of the fuel (Abad et al. 2012; Linderholm et al. 2013; Mattisson et al. 2009a). Research by Lyngfelt et al. (2001) has shown that the energy cost of solid circulation, which is the only energy cost of separation, is a very small percentage (approximately 0.3 %) of the total energy released by the combustion process compared to other pre-combustion technologies such as the oxy-fuel combustion in which the oxygen separation process consumes nearly 15 % of the electricity generation (Hong et al. 2009a, b). Therefore, CLC holds significant promise as a next-generation combustion technology due to its potential to allow zero CO₂ emission with little effect on the efficiency of the power plant.