Thermodynamic analysis of a novel oxy-combustion supercritical carbon dioxide power cycle integrating solar-driven coal gasification

Abstract

To advance the utilization of both coal resources and solar energy, a novel oxy-combustion supercritical carbon dioxide (sCO2) power cycle with solar-driven coal gasification integration was proposed and analyzed. In the proposed system, the concentrated solar energy is utilized for coal gasification to produce syngas for oxy-combustion to drive sCO2 power cycle with near-zero emission and the heat from air separation and hot syngas is recovered for coal drying, steam generation and sCO2 heating in a cascade way. Through introducing solar heat for coal gasification, the raw coal consumption is reduced and the oxygen production process can be eliminated, leading to a higher net system efficiency. The oxy-combustion power cycle can also be simplified owing to the better matching between the process waste heat and the steam generation for gasification. Detailed thermodynamic analysis showed that, the proposed system can save 28.3% of coal consumption with the net efficiency improvement of 1.6 percentage points, compared with the reference system. The solar-to-electricity efficiency can also reach as high as 23.3%.