Effect of Gas Recycle Rate on Net Plant Efficiency of A SPOC Power Plant

Abstract

Oxy-combustion technology is a promising near-zero carbon emission technology, however, its low efficiency and low economy limit its wide application to some extent. In this paper, a new thermal power system is proposed, which is a staged, pressurized oxy-combustion (SPOC) coupled with sCO₂ cycle coal-fired power generation system. The system was constructed and simulated by Aspen Plus v12, and the influence of flue gas recycle (FGR) ratio on system efficiency was studied. The research shows that: in the range of 10% - 55.53%, the net efficiency of the system gradually decreases with the increase of the recycle ratio. When the recycle rate is 50%, the efficiency decreases by 3.5% compared with the condition without gas recycle. However, the relationship between the net efficiency and the recycle ratio is not linear. The net efficiency is greatly lost when recycle ratio is higher than 27.8%, and less than 27.8%, the net efficiency loss is less than 1 percentage point.