Technical and economic feasibility evaluation of calcium looping with no CO2 recirculation

Abstract

Carbon capture and storage is expected to play a key role in decarbonisation of the power and industrial sectors, with calcium looping (CaL) being regarded as a well-developed technology that can reduce energy and economic penalties associated with mature technologies. Nevertheless, retrofits of CaL to coal-fired power plants result in net efficiency penalties of 5–8% points. The state-of-the-art CaL configurations assume that, similarly to oxy-fuel combustion systems, CO2 needs to be recycled to moderate the temperatures in the calciner. This study aims to assess the feasibility of CaL with no CO2 recirculation to the calciner via pilot plant testing and techno-economic analysis. The results collected during the experimental trials indicated that the temperatures inside of the calciner were within 930–950 °C, which were within the commonly reported operating temperature range of that reactor. Furthermore, the techno-economic analysis of the CaL retrofit to a conventional 580 MWel coal-fired power plant indicated that operation of CaL without CO2 recirculation will have a negligible effect on the net thermal efficiency of the entire system. Nevertheless, reduction in the size of the system resulted in a 21.7% reduction in the specific capital cost, and thus a 14.3% and 27.4% reduction in the levelised cost of electricity and cost of CO2 avoided, respectively. Therefore, CaL with no CO2 recirculation can be considered as a technically and economically feasible option to reduce the economic penalty associated with this emerging technology.