高背压供热机组利用低压旁路供热的分析研究

Analysis and Research of High Back Pressure Heating Unit Using Low Pressure Bypass for Heating

介绍了某135 MW等级高背压供热机组利用低压旁路供热的方法和系统设计,由机组高背压改造后的性能试验,得到机组高背压供热状态下各工况运行的性能指标,作为低压旁路供热性能分析的依据。在123 MW、110 MW、77 MW三个典型试验工况下,机组利用低压旁路供热,热化发电率降低28%~31.2%,凝汽器供热量增加51%~58%,全厂供热安全系数提高7.2%~10.4%;机组最低电负荷由77.36 MW降低到60.03 MW,约为高背压改造前额定功率的44.47%,小于纯凝状态锅炉的最低稳燃负荷。机组实施低压旁路供热改造后,供热能力增加,最低电负荷降低,机组调峰区间扩大,提高了低电负荷调度的灵活性。

The heating method and system design using low pressure bypass of a 135 MW high back pressure heating unit are introduced. Based on the performance test of the unit after retrofit of high back pressure, the performance indexes of each condition during heating period at high back pressure are obtained, which can be used as the basis of analyzing heating performance of low pressure by-pass. Under three typical test conditions of 123 MW, 110 MW and 77 MW, the low pressure bypass is used for heating. The thermalized power generation rate decreases by 28%~31.2%. The heat supply of condenser increases by 51%~58%, and the heating safety coefficient increasing by 7.2%~10.4% compared with its original value. The minimum electric load decreases from 77.36 MW to 60.03 MW. The reduced minimum power load is about 44.47% of the rated power output before retrofit, which is less than the lowest stable combustion load of the boiler at pure condensing state. After the low pressure bypass reformed, heating capacity of the unit has increased. The lowest electric load is reduced. The peak regulating interval of the unit has enlarged, improving the flexi-bility of low electric load dispatching.