火电厂的冷端损失是电厂热力系统最大的能量损失,大量的汽轮机凝汽器余热通过不同的冷却设备排放至大气中。高背压热电联产机组采用梯级供热,减少了机组的冷端损失,节能效果显著。以某电厂2×350MW机组为例,建立高背压余热梯级供热模型,结合供热季周期供回水温度变化,研究了双抽凝方式(EC-EC)、双抽背串联方式(EHBP-EHBP)在供热季运行时抽汽与负荷分配方式,利用热量法和?分析法,分析供热机组的经济性与热力学性能。结果表明高背压串联机组比抽凝机组供热季平均发电功率提升了26.2MW,平均发电标准煤耗降低了92.0g·(kW·h)-1,热经济性更好。供热季运行时高背压串联机组比原抽凝机组汽水?效率平均提升9.6%,额定供暖工况下?效率提升9.4%。

The cold end loss of the thermal power plant is the largest energy loss of the thermal system of the power plant. A large amount of steam turbine condenser waste heat is discharged into the atmosphere through different cooling equipment. The high back pressure cogeneration unit adopts cascade heating, which effectively reduces the cold end loss of the unit, and the energy saving effect is remarkable. Taking a 2×350MW unit of a power plant as an example, a high back pressure waste heat cascade heating model was established. Combined with the temperature change of the periodic supply and return water in the heating season, the extraction and load distribution modes of the double extraction condensation mode ( EC-EC ) and the double extraction back series mode ( EHBP-EHBP ) in the heating season were studied. The economic and thermodynamic performance of the heating unit was analyzed by using the heat method and exergy analysis method. The results show that the average power generation of the high back pressure series unit is 26.2MW higher than that of the extraction unit in the heating season, and the average standard coal consumption of power generation is reduced by 92.0g·(kW·h)-1, and the thermal economy is better. During the heating season, the steam-water exergy efficiency of the high back pressure series unit is 9.6% higher than that of the original extraction condensing unit, and the exergy efficiency is increased by 9.4% under the rated heating condition.

内蒙古自治区科技重大专项项目（No.2021ZD0036）；内蒙古自治区科技计划项目（No.2023YFHH0070）；内蒙古自治区“揭榜挂帅”项目（No.2023JBGS0012）