空气预热器漏风对机组能耗影响研究及其监测方法

Study on Influence of Air Preheater Air Leakage on Unit Energy Consumption and It’s Monitoring Methods

为了研究空气预热器漏风对机组性能的影响,以某330 MW循环流化床锅炉机组空气预热器为研究对象,建立了计算其漏风率对排烟温度、热风温度及风机电耗影响的热力学模型并进行了性能计算,结果发现,空气预热器漏风率对锅炉效率及风机电耗均影响较大,尤其是漏风点在空气预热器的热风出口处,在该处当漏风率为20%时对锅炉效率影响可以接近0.6%,同时增加风机电耗超过730 kW。除对机组经济性影响较大之外,空气预热器漏风还会对机组的可靠性产生较大影响,比如管式空气预热器会降低机组的出力,造成机组非计划降低出力事件;对于回转式空气预热器,可能还会造成机组非计划停运事件。为了更好的监控空气预热器漏风,还提出了一种监测空气预热器漏风率的方法,即通过监测相同工况下不同时间段空气预热器出口热风与进口冷风流量之间的差异来判断空气预热器漏风的严重程度,为合理安排空气预热器的检修周期提供了很好的参考依据。

In order to study the influence of air leakage of air preheater on the performance of the unit, this paper takes the air preheater of a 330 MW circulating fluidized bed boiler unit as the research object, establishes a thermodynamic model to calculate the influence of its air leakage ratio on the exhaust gas temperature, hot air temperature and fan power consumption, and conducts performance calculation. The results show that the air leakage ratio of air preheater has a great influence on the boiler efficiency and fan power consumption, especially, the air leakage point is at the hot air outlet of the air preheater, where when the air leakage ratio is 20%, the impact on the boiler efficiency can be close to 0.6%, and the power consumption of the fan can be increased by more than 730 kW. In addition to having a great impact on the economy of the unit, the air leakage of the air preheater will also have a great impact on the reliability of the unit. For example, the tubular air preheater will reduce the output of the unit, causing unplanned output reduction events of the unit, for rotary air preheater, unplanned shutdown of the unit may also occur. In order to better monitor the air leakage of the air preheater, this paper also proposes a method to monitor the air leakage ratio of the air preheater, that is, to judge the severity of air leakage of the air preheater by monitoring the difference between the flow of hot air at the outlet of the air preheater and the flow of cold air at the inlet in different periods of time under the same working condition, which provides a good reference for reasonably arranging the maintenance cycle of the air preheater.