Design And Implementation Of Advanced Control And Optimization Strategy For Hot Blast Stove

Hot blast stove is the most important heat exchange equipment in the production of ironmaking.It supplies stable high temperature hot blast for the blast furnace.The hot blast stove supplies about 1/4 of the heat consumption of hot blast furnace,so design and implementation of hot blast stove for advanced control strategy is the point to improve the stove combustion efficiency and energy saving.At present,the combustion control of the hot blast stove mostly adopts manual control,resulting in the combustion condition is not stable and the hot blast temperature is low.In order to improve the automation level of the stove control system and improve the quality of control,considering the characteristics of delay,time-varying and nonlinearity in the combustion process,this dissertation takes the hot blast stove of a steel company as the research object and advanced control and optimization strategy has been designed and implemented.The implementation has solved the problem on the plant site successfully.This dissertation has the follow main work:1.Considering to the characteristics of delay,time-varying and nonlinearity in flue gas temperature rising process,the heating rate correction is adopted,and the time-varying parameter model is identified online by the forgetting factor recursive least squares algorithm.The flue gas heating rate-gas flow cascade control scheme uses generalized predictive control and PID,which is respectively as the main controller and the sub-controller in the cascade loop.It has successfully solved the problem of combustion rate of the hot blast stove.2.The process of vault temperature variation has the characteristics of nonlinearity,multi-variety and time-varying.It is difficult to find a suitable air-fuel ratio by establishing an accurate mathematical model,so the combustion efficiency is not good.In order to solve this problem,a combustion optimization system has been designed and implemented.Back-propagation neural network is used to establish the model between air-fuel ratio and vault temperature.The genetic algorithm is used to find the best air-fuel ratio,which has improved the combustion efficiency of hot blast stove.3.The original control system on the site is upgraded to improve the automation level.The advanced control platform of hot blast stove is built,and the advanced control software is designed,and the parameters of each loop are tuned.The advanced control and optimization strategy of hot blast stove has been put into practical application and the air temperature of hot blast stove has increased.Combustion efficiency of hot blast stove and automation level have been improved.