A thermodynamic analysis and economic assessment of a modified de-carbonization coal-fired power plant incorporating a supercritical CO2 power cycle and an absorption heat transformer

An improved de-carbonization coal-fired power plant configuration incorporating a supercritical CO2 (S-CO2) power cycle and an absorption heat transformer (AHT) was proposed. The adopted S-CO2 power cycle efficiently absorbs the process waste heat within the CO2 capture process to drive a S-CO2 turbine to produce work, and the exhaust S-CO2 is beneficially utilized to preheat the air prior to the air pre-heater, saving a part of the flue gas energy, which can then be absorbed by the low-temperature economizer (LTE). An AHT is employed here to recover the remaining waste heat within the CO2 capture unit to vaporize the reboiler condensate for solvent regeneration. The mass and energy balance and the overall performance of the proposed system were determined by the developed models and process simulation. The detailed energy/exergy distributions of the reference and proposed plants were also investigated. Finally, the economics of the proposed system were assessed by the cost of electricity (COE) and the cost of CO2 avoided (COA). Results showed that the energy/exergy efficiency could reach 34.38% and 33.36%, respectively, better than the reference plant. The COE and COA of the proposed system were $92.21 /MWh and $46.27/t CO2, also showing an advantage over the reference one. (C) 2019 Elsevier Ltd. All rights reserved.