System integration optimization for coal-fired power plant with CO2 capture by Na2CO3 dry sorbents

For the post-combustion CO2 capture by the Na2CO3 dry sorbents, system integration of CO2 capture into an existing coal-fired power plant is of great significance, as the huge energy consumption of CO2 capture results in great efficiency penalty. By system integration optimization, nearly 80% of the low temperature energy released from the CO2 capture could be recovered to gain more power output and provide considerable heat supply for users, yielding a respective 0.6% and 34.13% increment of the net electric efficiency and coal utilization coefficient. Besides, combination with the waste heat recovery of flue gas further increases the net electric efficiency by 0.57%. Both the thermodynamic and exergy analysis results show that the optimization measures provide a promising way for system integration of the coal-fired power plant with CO2 capture. Techno-economic analysis results shows that cost of electricity and cost of CO2 avoided are obviously reduced due to the optimization measures proposed in this paper.