超临界压力机组低负荷滑压运行方式试验研究

针对国产首台超临界压力660 MW机组,通过机组不同调节阀运行方式的试验,得到机组热耗率和高压缸效率的变化规律,机组顺序阀运行方式下的热耗率和高压缸效率优于单阀运行,尤其是400 MW、500 MW低负荷工况,热耗率和高压缸效率差别较大;600 MW负荷以上工况,顺序阀运行跟三阀单阀运行的经济指标差别不大,其热耗率和高压缸效率都优于四阀单阀工况。机组在360～550 MW负荷范围内滑压运行,试验得到的最佳运行主汽压力与设计值不同。根据试验得到的实际滑压运行曲线和滑压运行特性,在相应工况下,机组在接近滑压曲线的工况附近维持较高的主汽压力运行,增大调节汽门的节流,可以快速增加负荷,增强机组的变负荷响应特性和调峰能力。

Experimental Investigation of Low-load Sliding Pressure Operation of Supercritical Pressure Unit

The changing regularity of heat consumption rate and HP cylinder efficiency are studied according to operational mode experiments on the first supercritical 660 unit of China, which shows that sequence valve operational mode can lead to lower heat consumption rate and higher HP cylinder efficiency compared with single valve operational mode. The gap between the two operational modes is obvious, especially when the unit is operated under low load such as 400 MW and 500 MW. When the unit is operated above 600 MW, sequence valve operational mode is actually the same as three-valve operational mode, leading to lower heat consumption and higher HP efficiency compared with fourvalve operational mode. The sliding pressure operational experiment from 360 MW to 550 MW presents optimum main steam pressure that is different from the design value, which lead to optimum sliding pressure operation curve and characteristic. Experimental result also shows that according to the optimum sliding pressure operation curve, the power load can be rapidly raised by increasing valve throttling with the unit operated under high steam pressure, which can improve the varying-load operational characteristic and adjusting ability of the unit.