集成余热回收的超临界二氧化碳燃煤发电系统研究

Study on supercritical carbon dioxide coal-fired power generation system integrated with waste heat recovery

锅炉排烟余热和冷端余热回收利用对提高超临界二氧化碳(S-CO2)燃煤发电系统发电效率具有重要意义。为此,本文提出一种集成排烟和冷端余热回收的S-CO2燃煤发电系统,并对该系统与常规S-CO2燃煤发电系统进行对比分析。结果表明:相比常规系统,集成排烟和冷端余热回收的S-CO2燃煤发电系统通过回收排烟余热和冷端余热,可使系统发电效率提高0.56%,发电标准煤耗率降低3.00 g/(kW·h);该系统可回收2.8 MW冷端耗散㶲,并有效降低锅炉传热㶲损7.3 MW,降低排烟㶲耗散4.9 MW,使得锅炉㶲效率提高0.65%,最终使系统㶲效率提高0.51%。

Waste heat recovery of the boiler exhaust and the cold-end is of great significance to improving the power efficiency of supercritical carbon dioxide(S-CO2)coal-fired power plant.Therefore,an S-CO2 coal-fired power generation system integrated with waste heat recovery of boiler exhaust and the cold-end is proposed in this paper.Moreover,comparative analysis between this system and the conventional S-CO2 coal-fired power generation system is carried out.The results show that,compared with the conventional S-CO2 coal-fired power generation system,the power efficiency of the proposed system increases by 0.56%and the standard coal consumption rate decreases by 3.00 g/(kW·h).The proposed system recovers the cold-end exergy loss of 2.8 MW,and reduces the boiler heat transfer exergy loss of 7.3 MW and the boiler exhaust exergy loss of 4.9 MW,resulting in an increase in exergy efficiency of the boiler and the system by 0.65%and 0.51%,respectively.