基于医疗垃圾汽化和燃料电池的新型发电系统性能分析

Thermodynamic and economic analysis on a new power generation system based on medical wastes gasification and fuel cell

为了提高系统的能量利用效率,提出了一种由医疗垃圾汽化(MSG)、固体氧化物燃料电池(SOFC)、超临界二氧化碳循环(S-CO_(2))和有机朗肯循环(ORC)组成的新型电力系统方案。医疗垃圾汽化产生的合成气与甲烷混合后进入SOFC子系统,为SOFC系统提供能量;经过SOFC系统后排放的尾气依然具有很高的温度,经过后燃室的充分燃烧,释放剩余未反应物质的化学能,进一步提高排烟温度;之后利用S-CO_(2)和ORC组合成的底循环系统对系统余热进行充分利用,以提高系统的整体性能。充分考虑系统热力学方面的关键参数以及系统的经济效益。结果表明,耦合的系统可以实现36.72 MW的电力输出,能量效率为66.34%,[火用]效率为64.07%。SOFC的[火用]损最大,占总[火用]损的21.64%。只需4.15年就能收回耦合系统的建设投资,在20年的使用寿命中获得1772.38万美元的净现值。

In order to improve the energy utilization efficiency of the system,a novel power system scheme is proposed,which consists of medical wastes gasification(MWG),solid oxide fuel cell(SOFC),supercritical carbon dioxide cycle(S-CO_(2)),and organic Rankine cycle(ORC).The syngas generated from the gasification of medical wastes is mixed with methane,and enters together the subsystem of SOFC to provide energy for the SOFC system.After passing the SOFC system,the exhaust gas still has a high temperature and is fully combusted in the afterburning chamber,releasing the chemical energy in the remaining unreacted substances and further increasing the temperature of exhaust gas.Then,the bottom circulation system composed of S-CO_(2)and ORC is employed to fully utilize the residual heat of the system,in order to improve the overall performance of the system.The key parameters in terms of system thermodynamics,as well as the economics of the system,are fully considered.The results show that the proposed system can achieve a power output of 36.72 MW with an energy efficiency of 66.34%and a heat-power efficiency of 64.07%.SOFC contributes the largest heat and power loss,accounting for 21.64%of the total heat and power loss.The construction investment of the coupled system can be returned in only 4.15 years,and a NPV of 17.7238 million US$is obtained over the 20-year service life.