燃烧扰动下炉膛压力的特性分析

Analysis on Furnace Pressure Characteristics Under Combustion Disturbance

采用机理分析和数据分析的方法,建立了炉膛压力与锅炉燃料量、送风量和引风量之间的非线性动态数学模型.在不同锅炉负荷下,对模型进行了线性化处理,得到燃料量对炉膛压力的传递函数,并对其进行了频域特性分析.结果表明:在燃料量扰动下,炉膛压力对象的频率特性在不同负荷下均呈现带通滤波特性,且燃烧扰动的主要频率分布在其通带内,控制系统本身难以直接对燃烧扰动进行有效抑制;在低负荷工况下,炉膛压力波动增大是由于对象自身的非线性特性造成的.

Using mechanism analysis and statistical analysis methods, a non-linear dynamic model of furnace pressure versus fuel flow, input air flow and output air flow was constructed. The transfer function of fuel flow versus furnace pressure was obtained after model linearization under different load conditions, which was analyzed by means of frequency domain characteristics analysis. Results show that the frequency domain characteristics of the model, which is fuel flow disturbance versus furnace pressure, have bandpass filter characteristics under different load conditions; since the major frequency of combustion disturbance is within the pass band of the object, it is difficult for the control system to effectively conquer the combustion disturbance; and it is the nonlinearity of the object itself that cause the aggravation of furnace pressure fluctuation under low load conditions.