脱硝装置控制系统的整合和优化

发布时间：2018-03-06 20:32

本文选题：脱硝　切入点：选择性催化还原　出处：《浙江大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着国内环保形势的日益严峻,我国政府越来越重视火电厂污染物的排放问题。氮氧化物是火力电厂排放的一项主要污染物,所以环保部门对氮氧化物的排放制定了非常严格的标准。作为一种脱硝效率高、氨逃逸率低的烟气脱硝方法,选择性催化还原(SCR)技术成为了许多电厂的选择。目前大多数电厂均在SCR控制系统中采用PID控制器,但由于SCR被控对象有非线性、大延迟的特点,所以在现场运行中,采用PID控制方式效果比较差。为了解决这些问题,改善控制品质,本文采用模型预测控制的方法对SCR控制系统进行优化,首先利用经过预处理的现场数据通过模型辨识获得过程模型,并对现有控制系统的控制特点和控制效果进行整合分析,进而运用MATLAB进行预测控制器设计并与现有控制方式进行仿真比较,最后就氨逃逸软测量和多变量模型预测控制在SCR控制系统中的应用进行仿真分析。仿真结果表明,模型预测控制可以很好的改善SCR控制系统的动态特性及抗干扰能力,提高SCR出口氮氧化物浓度控制品质,降低喷氨量。本文中的氨逃逸软测量的实现和SCR多变量模型预测控制的应用不但可以提高SCR控制系统的控制品质,也为实际的SCR控制优化提供了更加丰富的控制思路。
[Abstract]:With the increasingly serious situation of domestic environmental protection, the government of our country pays more and more attention to the emission of pollutants from thermal power plants. Nitrogen oxide is one of the main pollutants emitted from thermal power plants. So the environmental protection department has set very strict standards for NOx emissions. As a method of flue gas denitrification with high denitrification efficiency and low ammonia escape rate, Selective catalytic reduction (SCR) technology has become the choice of many power plants. At present, most power plants use PID controllers in SCR control systems, but because of the nonlinear and large delay characteristics of SCR controlled objects, they are in operation on the spot. In order to solve these problems and improve the control quality, the model predictive control method is used to optimize the SCR control system. Firstly, the process model is obtained by model identification using preprocessed field data, and the control characteristics and control effects of the existing control system are integrated and analyzed. Then the predictive controller is designed by using MATLAB and compared with the existing control methods. Finally, the application of ammonia escape soft sensing and multivariable model predictive control in SCR control system is simulated and analyzed. The simulation results show that, The model predictive control can improve the dynamic characteristics and anti-interference ability of SCR control system, and improve the quality of nitrogen oxide concentration control at the outlet of SCR. In this paper, the realization of soft sensing of ammonia escape and the application of SCR multivariable model predictive control can not only improve the control quality of SCR control system, but also provide more abundant control ideas for practical SCR control optimization.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X773

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