湿冷机组乏汽余热利用的新型热电联产系统集成优化

Integrated Optimization of a New Co-generation System Based on Waste Heat Recovery of Water-cooled Unit

针对湿冷机组提出一种新型的乏汽余热利用供热系统,通过机组高背压、热泵、热网低温回水3种成熟技术的结合,实现多热源的热网水梯级加热流程的构建。针对新系统提出了机组末级安全和新型热电联产系统能效评价指标及方法。以2×300MW湿冷机组为例构建系统模型,分析关键参数对系统能效及经济性的影响,结果表明,机组抽凝比xec越低,旁通水流量G1越大,系统供热等效电Weq.s及单位供热量总成本ct越低,且随着热网回水温度?1的降低,系统能效及经济性得到进一步改善,成果用于指导湿冷机组乏汽余热利用系统设计。

Aiming at the water-cooled unit, this paper put forward a new heating system based on waste heat recovery. Through the combination of ＂high back pressure＂, ＂absorption heat pump＂ and ＂low-temperature return water of the heat network＂ mature technologies, a cascade heating process of the heat network water with multiple heat sources was constructed. In the new system, the evaluation methods of the operation safety of unit＇s last-stage and the energy efficiency of the new co-generation system were proposed. Taking the 2~300MW unit as an object to construct a computing model, the effects of key parameters on the energy efficiency and economy of the system were analyzed. The conclusions indicate that the smaller the x~ （the ratio of the extraction steam and the exhaust steam） and the higher the G1 （the bypass water flow） are, the lower Weq.s （the heating equivalent electricity） and ct （the total financial cost per heating capacity） will be. In addition, with a further reduction of return water temperature rl, both the heating energy eff^ciency and the economy of the new system can be further improved. The results mentioned above can also be used to guide the design of the new system based on waste heat recovery of water-cooled unit.