适应深度调峰的广义回热系统热力特性研究

Study on the thermodynamic characteristics of generalized regenerative system used for deep peak load regulating operation

提高火电机组中低负荷运行经济性是当前深度调峰模式下的重要节能方向。本文介绍了5种广义回热系统的原理及特点,以某亚临界300 MW湿冷机组为研究对象,基于EBSILON软件建立的评估模型,计算分析了5种广义回热技术在机组不同负荷率下的参数变化和节能效果。计算结果表明:附加高压加热器联合外置蒸汽冷却器系统节能效果最大,改造后发电煤耗可下降1 g/(k W·h)以上;附加高压加热器与热风加热器联合系统,3抽热风加热器系统工程应用中需采取针对性的防磨措施;附加高压加热器系统、附加高压加热器与热风加热器联合系统有利于低负荷工况脱硝系统的投运和锅炉稳燃,在当前火电机组提高灵活性及深度调峰能力的迫切需求下,仍有一定的实用性。

Improving economy of low-load operation of thermal power units is an important energy-saving measure under the current situation of deep peak-regulating operation. This study introduces the principles and characteristics of five generalized regenerative systems. Taking a subcritical 300 MW wet and cold water unit as the research object, the evaluation models are established based on EBSILON commercial software. Parameter changes and energy-saving effect of five generalized regenerative technologies under different load rates of the unit are calculated and analyzed. The calculation results show that additional high pressure heater combined with external steam cooler system has the largest energy-saving effect. After the transformation, the coal consumption of the power generation can reduce by more than 1 g/（kW·h）. The combined system of additional high pressure heater and hot air heater and the 3 rd extraction hot air heater system need to take targeted anti-abrasion measures. Additional high pressure heater system and the combined system of additional high pressure heater and hot air heater are beneficial to the operation of the denitrification system and the steady combustion of the boiler at low-load operation, which has a certain practicability under the urgent need of increasing the flexibility and deeper peakregulating capability of thermal power plants.