基于EBSILON软件的二次再热MC机组变工况特性分析

以某电厂1 000MW二次再热机组为原型，使用EBSILON软件分别建立了外置式蒸汽冷却器和MC机组两种过热度利用方式的系统模型，通过计算分析二次再热机组给水温度、各级回热抽汽过热度降低值等参数，得出了MC系统变工况特性。计算结果表明：在热耗率验收（THA）工况下，外置式蒸汽冷却器可降低煤耗0.446g/kWh，而MC系统节能效益更加明显，为2.104g/kWh；随着机组负荷的逐渐降低，外置式蒸汽冷却器节约煤耗量逐渐升高，40%THA工况下达到0.869g/kWh，MC系统则降低至0.924g/kWh。由此表明，在低负荷下MC系统节能效果下降，但综合节能效果显著。

Analysis of Off-design Characteristics of Two Reheat MC Unit Based on EBSILON

The 1 000 MW two reheat units of a power plant are taken as the prototype,and the system model of two kinds of overheat use mode of external steam cooler and MC system is established by using EBSILON software.By calculating and analyzing the parameters of the water supply temperature of the two reheat units and the reduction of the overheat at all levels of the regenerative steam,the variable working condition characteristics of the MC system are obtained.The calculation results show that the external steam cooler can reduce the coal consumption by 0.446 g/kWh,and the energy saving benefit of MC system is more obvious,which is 2.104 g/kWh.With the gradual decrease of the load of the unit,the coal consumption of the external steam cooler is gradually increased and 0.869 g/kWh is reached under the 40% turbine heat acceptance working condition,and the system is reduced to 0.924 g/kWh.The energy saving effect of MC system decreases under low load,but the effect of comprehensive energy saving is remarkable.