低氮燃烧锅炉汽温防超温控制策略研究及应用

Research and Application of Preventing Boiler Steam Overheating Strategy for Heat Supply Unit

低氮燃烧改造后的锅炉,低氮燃烧和非低氮燃烧模式的切换使得汽温的变化幅度增加,汽温控制中需要的减温水量变化幅度增大。针对这些特性,提出利用蒸汽焓值计算平衡热势能的汽温预估控制算法,计算得到不同工况下所需的减温水量,采用汽温设定值自动分配算法以及壁温自动修改设定值算法,对各级汽温设定值进行实时整定,利用"主蒸汽温度控制中二级减温水阀门位置自寻优方法"的控制技术,对末级以前的减温控制设定值进行自动设定,实现锅炉在各种负荷情况下的汽温精确控制,明显提升汽温自动控制的性能,实现了各级减温水的自动分配,降低了汽温和壁温的超温次数。

Boiler after transformation Low nitrogen combustion, low nitrogen and non-low nitrogen combustion mode switch increases the range of steam temperature change, The range of desuperheating water flow for steam temperature control has been great。According to these characteristics, this paper proposes using the steam enthalpy calculation heat balance the potential energy of the steam temperature forecast control algorithm, under different working conditions, calculated the desuperheating water flow, the steam temperature setpoint is automatically assigned and modified bu wall temperature value。The control of reduction temperature control setpoint of all stage except last are set automatically, using the ＂secondary temperature-decreased water valve position automatically optimize in the main steam temperature control ＂ patent technology, the steam temperature is precision under control in various load cases of the boiler, the performance of steam temperature automatic control has been significantly improved, temperature-decreased water for each level can be automatically assigned, the frequency of overtemperature of the steam temperature and wall temperature has been reduced.