小龙潭电厂300MW机组热力系统分析

Exergy Analysis on Thermal System of a 300MW Unit in Xiaolongtan Power Plant

应用能量平衡和分析方法,对小龙潭火力发电厂300 MW机组热力系统能量转换过程进行了定量计算,分析了各个单元的能量有效利用及损失情况,指出了损失的主要部位和原因.结果表明:热量损失主要发生在凝汽器单元,凝汽器散失到周围环境中的热量为411.28 MW,占输入热量的51.57%,锅炉单元散失的热量为52.96 MW,占输入热量的6.64%,汽轮机单元散失的热量为20.40 MW,占输入热量的2.56%;损主要发生在锅炉单元,锅炉、汽轮机和凝汽器单元的损分别占输入的67.78%、18.54%和13%;锅炉中燃料燃烧及大温差传热是整个系统不可逆的主要原因;不同工况下每个单元的损和效率会随着环境温度适度改变,但同一工况下机组总的效率不随环境温度变化.

Using energy balance and exergy analysis method,quantitative calculation was carried out for the energy conversion process of thermal system of a 300 MW unit in Xiaolongtan thermal power plant.Energy utilization and loss of each unit were analyzed,and the main location and causes of heat loss were pointed out.Results show that heat loss mainly occurs at condenser unit.The heat dissipated to the environment from the condenser is about 411.28 MW,accounting for 51.57% of the input heat.While the heat loss of boiler unit is about 52.96 MW,accounting for 6.64% of the input heat,and the heat loss of turbine unit is about 20.40 MW,accounting for 2.56% of the input heat.Exergy loss occurs mainly at boiler unit.Exergy losses of boiler unit,turbine unit and condenser unit occupy 67.78%,18.54% and 13% of the input exergy respectively.Fuel combustion and heat transfer at large temperature difference in boiler unit are the main causes for the irreversible process of the whole system.Under different working conditions,the exergy loss and exergy efficiency will change with the environmental temperature,while the total exergy efficiency won＇t change with the environmental temperature at a same working condition.