高背压供热机组凝汽器高低背压运行的经济指标分析

介绍150 MW高背压供热机组,凝汽器为满足高背压供热进行的配套改造内容。由机组高背压供热改造后,凝汽器高、低背压运行的试验数据,计算凝汽器在两种运行状态下的性能指标。凝汽器在高、低背压两种工况下运行,循环水流量与设计值比较吻合,凝汽器端差、过冷度基本都达到了设计值。高背压工况下,凝汽器端差较小,为2.264℃;正常背压工况下,凝汽器端差也小于通常设计端差4℃,修正后的总体传热系数和凝汽器端差与改造前相差不大;高背压工况下的凝结水过冷度为0.555℃,稍高于设计保证值。凝汽器进行高背压改造,达到常年安全运行和经济运行的要求。凝汽器在高、低背压下运行,可以进一步根据电、热负荷,调整循环水泵、热网水泵的水量和运行方式,提高机组供热期的发电量、降低非供热期的运行背压,以提高机组全年运行的经济性。

Economic Indicator Analysis of High Back Pressure Circulating Water Heat Supply Unit Operating in High and Low Back Pressure Modes

The condenser reconstruction of 150 MW unit for meeting the need of high back pressure circulating water heat supply is introduced. Economic indicators of the reconstructed unit are calculated by using the experimental data in high and low back pressure operating modes. The experimental data shows that, operating both in high and low back pressure modes, the flow rate of circulating water is close to design value, the condenser terminal temperature difference and depression can also reach to the guarantee values. As the unit operating in high pressure mode, the condenser terminal temperature difference is 2.264 ℃, which is lower than design value 4℃. As the unit operating in normal pressure mode, the condenser terminal temperature difference is also lower than design value. However, after corrected, the condenser terminal temperature difference is very close to the values before the reconstruction, as well as the whole heat-transfer coefficient. As the unit operating in high pressure mode, the condenser depression is 0.555 ℃, which is slightly higher than the guarantee value. The analysis shows that, by reconstructing the condenser, both the safety and economical efficiency during the whole year can be guaranteed with the unit operating in high and low back pressure modes, the operating modes and flow rate of circulating pump and heat supply pump can be easily regulated according to heat-electric load distribution, which can increase the electric load during heating period and decrease the back pressure in the rest time of the year.