直流锅炉启动过程中热回收能力的分析与计算

今后越来越多的火电机组将要承担温态启动和热态启动的调峰任务，因此启动过程中回收热量的能力将直接影响火电机组的运行经济性。该评议对直流锅炉启动过程中热回收能力作了分析，建立了计算热回收能力的数学模型，并对模型进行了实验验证。在此基础上对300MW，600MW直流锅炉启动系统的热回收能力作了定量计算，详细分析了直流锅炉启动系统滑压启动时分离器水位控制旁路阀前疏水压力、疏水流量等参数变化时除氧器水箱的压力变化速率，压力飞升曲线的热回收能力。理论分析和实验都说明，直流锅炉启动系统的热回能力主要取决于启动分离器和除氧器水的工作压力以及除氧器水箱的容积。该分析对直流锅炉启动旁路系统的设计与计算具有一定的参考价值。

ANALYSIS AND CALCULATION OF HEAT RECOVERY FROM THE STARTING VESSEL OF A ONCE-THROUGH BOILER SYSTEM

An increasing number of coal and oil fired boilers are employed in covering the week day load and are shut down at weekends. Therefore the ability for heat recovery from starting vessel will directly affect the economy of the operation in a once through boiler unit. This paper describes an attempt to calculate the amount of heat recovery in a once through boiler system during its start up. A mathematical model has been firstly developed and an experimental study is carried out to check the model. The 300?MW and 600?MW once through boiler system are taken as the examples. The pressure rise rate, pressure rise curve and recoverable heat analysis which are significant to improve the operation reliability and economy for the domestic made deaerator tanks have been given out. Both theoretical analysis and experimental studies show that the capacity for heat recovery in the deaerator tank largely depends on the working pressure of the deaerator tank and the starting vessel. The volume of the deaerator tank, especially the volume of water has a large effect on the heat recovery capacity. These analysis results can be applied to the design and operation control of the deaerator tanks.