Energy, exergy and economic(3E) analyses of a CO 2 near-zero-emission power generation system with integrated supercritical water gasification of coal and SOFC

Based on the compositional properties of the syngas produced by supercritical water gasification (SCWG) of coal, a CO 2 near-zero-emission power generation system with integrated supercritical water gasification of coal and solid oxide fuel cell (SOFC) is proposed. The chemical energy of the syngas is cascade utilized by the SOFC and gas turbine to generate electricity. The exhaust gas from the anode of SOFC is combusted with pure oxygen in the combustor of the gas turbine to produce high-temperature flue gas which is consisted of CO 2 and H 2 O. The CO 2 can be easily separated and captured from the flue gas. The heat for preheating the feed water of the gasifier and driving the gasification reactions is provided by the exhausts of the combustor, SOFC cathode, and the exothermic heat produced through electrochemical reaction in the SOFC. The influences of key parameters such as the temperature of the SOFC and fuel utilization rate on the system performance are investigated, and the distribution law and transfer conversion mechanism of the energy and exergy are revealed. When the temperature of the SOFC is 1000 degrees C, and the fuel utilization rate is 83 %, the power efficiency of the system is 43.65 % and the exergy efficiency is 42.61 %. In addition, the CO 2 capture rate is close to 100 %. Economic analysis is also performed. The levelized cost of electricity (LCOE) of the proposed power system is 0.272 & YEN;/kWh. CO 2 near-zeroemission is realized through combining the electrochemical reaction within the SOFC and the oxy-combustion in the combustor of the gas turbine, which is of great significance to achieve the carbon peak and carbon neutrality goals.