基于时延补偿的燃煤机组二氧化硫排放浓度抗干扰控制

Disturbance rejection control of sulfur dioxide emission concentration of coal-fired unitsbased on delay compensation

针对1000 MW燃煤机组脱硫过程能耗高及定值控制实现难的问题,进行了二氧化硫出口浓度闭环控制方法研究。首先,基于开环辨识建立了不同典型负荷点脱硫塔内调控泵频率与出口二氧化硫浓度之间的面向控制器设计的传递函数动态模型。其次,采用了结合史密斯预估器和扰动与不确定性估计技术(UDE)的闭环控制方案,在补偿脱硫过程大范围时延的同时增强闭环系统对模型不确定性和外部干扰的抑制能力。最后基于充分的鲁棒性评估确定了控制策略的参数。仿真和现场应用结果表明,论文研究的控制方法能够实现燃煤机组出口二氧化硫浓度的定值控制,并具备较为出色的瞬态响应性能。

In order to address the issues of high energy consumption and challenge of set-point control in the desulfurization process of a 1000 MW coal-fired unit,we investigate a closed-loop control method for sulfur dioxide(SO2)concentration at the outlet of the desulfurization tower.Firstly,a dynamic model between the frequency of the regulating pump inside the desulfurization tower and the outlet SO2 concentration at different typical unit load points is established based on open-loop identification.Secondly,a closed-loop control scheme was introduced using a combination of Smith predictor and uncertainty and disturbance estimator(UDE),which can compensate for the large delay in the desulfurization process while enhancing the suppression capability of the closed-loop system against model uncertainties and external disturbances.Finally,based on sufficient robustness evaluation,the control parameters are determined.Simulation and application results show that the studied control method can achieve set-point control of the outlet SO2 concentration of the coalfired unit,and exhibit excellent transient response performance.