Research On Control Of Cement Denitration Process Based On Typical Working Conditions

China's cement production industry is developing rapidly,and its nitrogen oxide emissions are increasing year by year,accounting for 10% to 20% of the country's total emissions.Nitrogen oxides are one of the main atmospheric pollutants controlled by the state and cause great harm to the environment and people's health.Therefore,the control of nitrogen oxides becomes very important.At present,most of the denitrification technologies of domestic cement enterprises are selective non-catalytic reduction technology(SNCR),and there are still many problems in this technology for a long time.The control method of SNCR denitration technology is a manual control or semi-automatic control strategy,while manual control is subjective and random,which not only consumes manpower but also causes excessive fluctuation of nitrogen oxide concentration,excessive emission,and large consumption of ammonia problem.Due to the certain hysteresis of the denitration process and the fluctuation of typical operating conditions caused by changes in the operating parameters of the kiln system over a long period of time,simple automatic control algorithms or even advanced control algorithms of a single model cannot achieve effective control of the system.With the application of various advanced control algorithms in some industrial fields,in order to solve the above problems,a more intelligent control strategy is adopted for the cement denitration process control system.This paper has carried out a series of researches.The denitration reaction process of cement is affected by the firing system,and the important parameter data of the firing system is collected.The historical data is clustered and analyzed by K-Means,and the typical working conditions of the denitration system are divided.Through the fluctuation range of the clustering center point of typical working conditions,the fuzzy weighting method is used to formulate the working condition output rule table,and the typical working condition type and the weighting coefficient under typical working conditions are given.Through the MATLAB system identification toolbox,the transfer function model under typical working conditions is identified,and the model switching rules for each typical working condition switching are established according to the working condition rule output table to avoid the system oscillation caused by the hard switching of the model;Based on the dynamic response characteristics of the denitration process model under typical working conditions,the dynamic matrix control strategy is proposed and introduced in detail.The optimal control parameters under typical working conditions are selected by MATLAB simulation.Dynamic matrix control(DMC)under multiple operating conditions.The control strategy has good tracking,stability and robustness,and can effectively solve the problem of multiple working conditions and long lag time of cement denitration system;The online calculation process of DMC was briefly introduced and a series of control rules were formulated to lay the foundation for the design and implementation of control software.