Proposal and investigation of a high-efficiency coal-fired power generation system enabled by chemical recuperative supercritical water coal gasification

Gasification process is a promising technology for efficient and clean utilization of solid fuels that has been attracting increasing attention. This paper proposes a high-efficiency coal-fired power generation system enabled by chemical recuperative supercritical water coal gasification. The main feature is that the reaction heat of gasification process is supplied by the high-temperature flue gas generated by the gas turbine, which can be achieved by adjusting the pressure ratio. Since coal can be converted into clean syngas with supercritical water at 600-700 degrees C without the oxidation of part of the fuel to provide reaction heat, the exergy destruction of gasifi-cation process is decreased dramatically and a small amount of chemical energy of coal is converted into thermal energy. The results showed that in the proposed system and reference system, the net power generation effi-ciencies are 53.8% and 48.9%, respectively; and the corresponding exergy efficiencies are 52.5% and 47.7%, respectively. It is observed that in the proposed system, the net power generation and exergy efficiencies increased by 4.9 and 4.8% points, respectively. Additionally, the mechanism of exergy destruction reduction is revealed by the graphical exergy analysis, and the comprehensive cascade utilization of chemical and thermal energy is realized.

Automated summary

This paper proposes a high-efficiency coal-fired power generation system enabled by chemical recuperative supercritical water coal gasification. The results showed that in the proposed system, the net power generation and exergy efficiencies increased by 4.9 and 4.8% points, respectively.