给水温度对机组汽温及煤耗率的定量分析模型

The Quantitative Analysis Model of Feed Water Temperature on Steam Temperature and Coal Consumption Rate

为分析给水温度变化对火电机组煤耗和汽温的影响,进而指导机组的安全经济运行。基于微分理论、热力学方法和能量守恒原理,构建了火电机组给水温度变化对煤耗率和汽温特性影响的数学模型。以某电厂1台600 MW机组为例,选取2个不同工况进行计算。计算结果表明:随着给水温度的增大,排烟温度升高,锅炉热效率下降,汽轮机热耗率降低,而机组的发电标准煤耗率减小。此外,给水温度升高,在发电功率一定的情形下,机组的过热蒸汽温度和再热蒸汽温度降低。该模型计算量小,精度高,能够准确反映给水温度变化对锅炉热效率、汽轮机热耗率、机组煤耗率及汽温特性的影响,可为火电机组节能降耗的实施提供理论参考依据。

In order to analyze the influence of feed water temperature change on coal consumption and steam temperature of thermal power units, and then guide the safe and economic operation of the unit, a mathematical model of influence of feed water temperature change on the coal consumption rate and the steam temperature characteristic in thermal power unit was constructed based on the differential theory, the thermodynamic method and the energy conservation principle. Taking a 600 MW unit of an electric power plant as an example, the characteristics of economy and steam temperature of two different working conditions were calculated. The calculation results show that, with the increase of feed water temperature, the flue gas temperature is elevated, the boiler efficiency, heat consumption rate of the steam turbine and the standard coal consumption rate of the generating unit are reduced. In addition, as the feed water temperature is raised, the superheated steam temperature and reheat steam temperature of unit would be reduced under the condition of fixed power generation. The model has small calculation and high precision, and can accurately reflect the influence of feed water temperature change on boiler thermal efficiency, steam turbine heat consumption rate, coal consumption rate and steam temperature characteristics of the unit. It can provide a theoretical reference for the implementation of energy saving and consumption reduction of thermal power units.