300MW低位能供热机组凝汽器双温区运行灵活经济性分析

Analysis on Flexibility and Economical Effect of Dual-temperature Zone Operation of Condenser for 300MW Low-level energy heating unit

为提升湿冷机组低位能供热系统的热电解耦能力,提出凝汽器双温区运行方式,并以典型300 MW等级热电联产湿冷机组为例,分析凝汽器双温区运行对低位能供热机组灵活性的影响,以及基于热力学第二定律的供热耗能概念,开展凝汽器双温区运行的供热经济性分析。研究结果表明:同样在承担1000 GJ/h热负荷条件下,基于凝汽器双温区运行的低位能供热系统的调峰区间,相比常规低位能供热系统提升了154 MW,相比抽汽供热方式提升了77 MW。基于凝汽器双温区运行的低位能供热系统可提升低位能供热机组的调峰区间,但供热经济性下降,当余热回收比例在40%以上时,与常规抽汽式供热相比仍具备供热经济性。

In order to improve the thermoelectric decoupling capability of low-level energy heat supply system for wet-cooling units,the dual-temperature zone operation mode of condenser is proposed.Taking a typical 300 MW combined heat and power wet-cooling unit as an example,the contribution of the dual-temperature zone operation of condenser to the heating flexibility of low-level energy heating unit is analyzed,and based on the concept of heating energy consumption in the second law of thermodynamics,the impact of the dual-temperature zone operation of condenser on the economical effect of heat supply is analyzed.The results show that:under the same condition of bearing 1,000 GJ/h heat load,the peak regulation range of lowlevel energy heat supply system based on the dual-temperature zone operation of condenser is increased by 154 MW compared with that of conventional low-level energy heat supply system,and increased by 77 MW compared with that under extraction heating mode.The low-level energy heat supply system based on dualtemperature zone operation of condenser can improve the peak regulation range of the low-level energy heating unit,but with decrease of economical effect of heating.If the waste heat recovery ratio is more than 40%,it still has better economical effect compared with conventional extraction heating.