Research And Application Of Internal Model Control In Wet Flue Gas Desulfurization System

In order to adapt the rapid development of the electric power industry and theneed of doing a good job of environmental protection, our country has establishedmore strict environmental standards to control the emission of air pollutants ofcoal-fired power plants to manipulate air quality and the acid rain pollution. In thissituation, coal-fired power plants across the country have carried out the constructionof flue gas desulfurization project. The limestone/gypsum wet flue gas desulfurizationprocess accounts for over90%of the commission of flue gas desulfurization unit. Atthe same time, due to less operating experience and lack of research and knowledgefor the operation mechanism, there will appear the situation of instability anddesulfurization efficiency is not ideal during the process of the operation of thedesulfurization system.Ideal desulfurization efficiency is the control objective must be achieved in fluegas desulfurization system of coal-fired power plants. Based on in-depth analysisof wet flue gas desulfurization process, according to the double film theory andthe theory of multiple regression, we know the mainly parameters that affect on thedesulfurization efficiency and quantitative analysis of the impact of the majorinfluencing parameters, having studied the pH value of absorber slurry is the primaryfactor affecting the the desulfurization efficiency; Using the recursive least squaresidentification method based on Hammerstein model, have got a mathematical modelwhich is very close to the pH neutralization process of absorber slurry.The control process of pH value in the slurry absorber is a typical nonlinear andlarge delay links,and traditional control methods are difficult to obtain satisfactorycontrol performance.Internal model control is a very practical control method, whosemain characteristics are a simple structure, low model accuracy requirements, greatlyimprovement of the robustness and stability of the system, and can eliminate theunmeasured disturbances on the system. This paper applied the linearizationmethod for combining internal model control Control to study the pH neutralizationprocess. The results of MATLAB simulation analysis show that the internal modelcontrol algorithm for the pH neutralization process has good control effect, andinternal model control is a appropriate method to wet flue gas desulfurization system.