A novel coal-based Allam cycle coupled to CO2 gasification with improved thermodynamic and economic performance.

Coal-based Allam cycle is an advanced low-carbon and efficient power cycle that uses syngas produced by coal gasification to drive the semi-closed supercritical CO 2 cycle for electric power generation. To improve the thermodynamic and economic performance, a novel coal-based Allam cycle coupled to CO 2 gasification is proposed. Compared to the reference system, the steam for gasification is eliminated and the mole fraction of H 2 within the raw syngas is reduced, which could effectively decrease the moisture fraction of the combustion flue gas and give enough margin to intensify heat integration. Thereby, more process heat has been saved to drive the efficient supercritical CO 2 cycle and the raw syngas cooling heat is further recovered by the main recuperator. Results show that the net efficiency of the novel system soars to 43.99%, which is enhanced by 0.67% points. Moreover, the exergy efficiency increases by 0.65% points with the total exergy destruction and loss reduced by 1.23%. In addition, the total plant investment (TPI) and the cost of electricity (COE) are reduced by 1.42% and 1.39%, respectively, which proves that the novel system is also superior for commercial application. • CO 2 gasification of coal is coupled to a semi-closed supercritical CO 2 cycle. • Heat integration is improved with the elimination of steam for gasification. • Energy/exergy efficiency is enhanced by 0.67/0.65% points. • Superior economic performance is obtained with COE decreased by 1.39%. [ABSTRACT FROM AUTHOR]