Evaluation of a calcium looping CO2 capture plant retrofit to a coal-fired power plant

Carbon capture and storage is expected to provide a cost-effective means of CO2 emission reduction from the power sector. Amine-based post-combustion CO2 capture is a suitable option for coal-fired power plants in retrofit scenarios. However, the energy requirement for solvent regeneration in chemical absorption CO2 capture processes causes a substantial reduction in the power plant efficiency and power output. Therefore, novel technologies with lower efficiency penalties need to be developed. One promising option is calcium looping (CaL) which is based on the reversible carbonation-calcination reaction of limestone that takes place at high temperature. In this study, the CaL process model was developed and compared with pilot-plant data from the open literature. The verified model was then integrated with a high-fidelity model of the 580 MWel coal-fired power plant characterised by the net thermal efficiency of 38.5% HHV and a secondary steam cycle. A sensitivity analysis was conducted to determine the optimal operating conditions for industrial scale. The results indicate that the efficiency penalty imposed by the CaL plant is in the range of 6.7-7.9 Such performance compares favourably to the best cases amine and chilled ammonia scrubbing options, which have efficiency penalties of 9.5% and 9.0%, respectively.