兼顾氨逃逸与出口NO_x的火电厂SCR系统多模预测控制  

Multi-mode Predictive Control for Thermal Power Plant SCR System considering Ammonia Slip and Export NOx

作　　者：肖运启[1] 储伴俊 XIAO Yun-qi;CHU Ban-jun(North China Electric Power University)

机构地区：[1]华北电力大学,北京102206

出　　处：《电站系统工程》2020年第4期7-11,共5页Power System Engineering

基　　金：中央高校基本科研业务费专项资金(2018MS27);国家自然科学基金资助项目(51677067)资助。

摘　　要：针对火电厂选择性催化还原(SCR)脱硝系统出口NOx定值串级控制策略控制品质与鲁棒性难以满足要求的问题,提出多模自动切换的有约束的模型预测控制(MPC)策略来控制喷氨阀门开度。为了模拟SCR系统大范围工况的动静态特性在多个平衡点进行线性化,对线性化后的多个模型自动切换的方式进行了分析。为了简化预测控制在线计算过程,对实际约束条件下的控制量用降维的方法进行迭代计算。控制方案兼顾氨逃逸、出口NOx浓度两个指标,并且在氨逃逸量过大时可自动提高氨逃逸权重因子。采用适用于大范围工况机理模型的仿真结果表明,多模预测控制调节速度快、动态误差小、鲁棒性强,有效地提高了控制品质。For the selective catalytic reduction(SCR)denitration system of thermal power plants,the control quality and robustness of outlet NOx fixed value cascade control are difficult to meet the requirements..A multimode automatic switching and constrained model predictive control(MPC)strategy is proposed to control the ammonia spray valve opening.In order to simulate the dynamic and static characteristics of the SCR system in a wide range of working conditions,linearization is performed at multiple equilibrium points,and the manner of automatic switching of multiple linearized models is analyzed.In order to simplify the online calculation process of predictive control,the control variable is dimensionally iteratively calculated in a dimension-reduction method under actual constraints.The control scheme takes into account two indicators of ammonia escape and outlet NOx concentration,and automatically increases the ammonia escape weight factor when the ammonia escape is too large.The simulation results based on the mechanism model applicable to large-scale working conditions show that the multimode predictive control has fast adjustment speed,small dynamic error and strong robustness,which effectively improves the control quality.

关 键 词：SCR脱硝系统 多变量 有约束预测控制 多模型 氨逃逸 自动调整权重 

分 类 号：TM621[电气工程—电力系统及自动化] TP29[自动化与计算机技术—检测技术与自动化装置]