增设无再热汽轮机热电联产系统节能研究

Energy Saving Research of a Novel Combined Heat and Power System Integrating With a Non-reheat Steam Turbine

随着燃煤机组参数的提高,对纯凝机组进行传统抽凝供热改造会由于供需压力不匹配,造成较大的节流损失。针对此问题提出增设无再热汽轮机的热电联产系统,即部分蒸汽由高压缸做功后不进入锅炉再热器,直接进入增设的汽轮机膨胀做功后排汽供热。结合某600MW机组利用EBSILON?Professional对系统进行建模和供热改造计算,并进行综合经济效益节能分析。结果表明:当供热负荷为360MW时,采用传统抽汽供热和新型供热系统一次能源利用率较纯凝工况分别增加21.0%和25.55%,等价标准煤耗率分别降低4.97g/(k W?h)和13.25g/(k W?h)。新型供热系统展现出较优的节能效益。

During the traditional process of heating retrofitting, the pressure of steam extracted from turbine is much higher than the heating pressure required, leading to great throttling loss. Such problem becomes more serious with higher steam parameters in coal-fired power plant. To solve the problem, a novel combined heat and power（CHP） system with a non-reheat steam turbine was proposed. After leaving high pressure turbine, some of the steam flow into the non-reheat steam turbine to generate power rather than to the reheater in boiler, of which, the exhaust steam can be used for heat supply. A practical 600 MW power generating unit was selected as object, with which the model was built by EBSILON（R） Professional. Two kinds of heating retrofitted system were simulated, as well as the composite economic results were analyzed. The results indicate that when the heat demand is 360 MW, the gross efficiency increases by 21.0% and 25.6%, and equivalence standard coal consumption rate decreases by 4.97g/（k W·h） and 13.25g/（k W·h） for the traditional and novel heating supply systems respectively. The novel CHP system shows the more benefits of energy saving.