高背压供热具有提高机组整体热经济性和增强机组供热能力的优势，本文基于某600 MW亚临界直接空冷高背压抽凝供热机组Ebsilon仿真模型，从安全运行边界、经济性、供热能力、调峰能力和热电耦合性等方面对不同供热期的机组运行背压开展特性分析及调整优化研究。结果表明：当环境温度低于5 ℃时机组推荐运行背压为33 kPa，在5~11 ℃之间时需根据供水温度调整背压运行，高于11 ℃时推荐运行背压为13 kPa；随着背压抬高，机组的最小安全流量从140.4 t/h上升至336.5 t/h；乏汽供热火用效率明显高于抽汽供热火用效率，最大值可达到86.7%；机组在低供热需求下抬高背压会降低调峰能力，在较高供热需求下背压变化引起的调峰容量波动小，热电耦合性强，解耦度变化小。

High back pressure heating has the advantages of improving the overall thermal economy of the unit and enhancing the heating capacity of the unit. In this paper, based on the Ebsilon simulation model of a 600 MW subcritical direct aircooled high back pressure pumped condensing heating unit, the characteristics analysis and adjustment optimization study of the unit operating back pressure in different heating periods were carried out in terms of safety operation boundary, economy, heating capacity, peaking capacity and thermoelectric coupling. The results show that when the ambient temperature is lower than 5 ℃, the recommended operating back pressure is 33 kPa, and the back pressure needs to be adjusted according to the water supply temperature from 5 to 11 ℃, and the recommended operating back pressure is 13 kPa when it is higher than 11 ℃; the minimum safe flow rate of the unit increases from 140.4 t/h to 336.5 t/h as the back pressure is raised; the exergy efficiency of the spent steam heating and distribution system is significantly higher than that of the extracted steam heating and distribution system, with the maximum value of 86.7%; the unit will reduce the peaking capacity when the back pressure is raised under low heating demand, and the peaking capacity fluctuation caused by the change of back pressure under higher heating demand is small, with strong thermoelectric coupling and small change of decoupling degree.

TK11+4

国家自然科学基金面上项目（51976031）；江苏省基础研究计划（自然科学基金）青年基金项目（BK20210240）