Study On Intelligent Control Method Of Converter Steelmaking Based On Expert System

Since the advent of converter in 1850 s,it has gradually become the main production equipment of steel in the world.The autonomous control of converter steelmaking process has also become a hot topic in the control field.Limited by the harsh production environment and changeable boundary conditions of some domestic iron and steel enterprises,many mature autonomous control methods at home and abroad cannot be applied in actual production.However,the workers can produce normally.Therefore,it is of great significance to collect expert knowledge and establish an autonomous control system based on expert system for converter steelmaking.This thesis takes the converter as the research object,introduces its development history,production technology and control method.In order to reduce the cost and ensure the quality,the real-time carbon temperature calculation model,dynamic feeding calculation model and dynamic terminal calculation model are put forward.Based on these three models,an intelligent control system of converter steelmaking based on expert system is developed according to object-oriented programming.The real-time carbon temperature calculation model is used to calculate the realtime carbon content and temperature in the molten pool.The real-time carbon temperature calculation model comprehensively considers the decompression of carbon,silicon,manganese,phosphorus and iron oxides and the effect of their respective concentrations on the reaction rate of the elements.The reaction weights of each element are formulated,and the reaction weights and concentration are used as the two elements for oxygen distribution.After calculating the oxygen occupied by each element,the model calculates the residual amount of elements,the heat released,the residual amount of molten iron and the amount of slag according to the material balance and thermal balance.Then the real-time carbon content and real-time temperature of molten iron are calculated.After correcting the weights of the model according to the actual production data,the model has a considerable hit rate in calculating the carbon temperature.The dynamic feeding calculation model is based on the real-time carbon temperature to dynamically calculate the feeding quantity and generate the feeding plan model.Based on the content of each element,the amount of iron,the temperature of molten iron and the amount of slag calculated by the real-time carbon temperature calculation model,the feeding quantity is calculated dynamically and the feeding plan is generated according to the expert knowledge and rules in the expert system.The dynamic terminal calculation model is similar to the dynamic feeding calculation model,which is based on the results of real-time carbon temperature calculation model and expert knowledge to dynamically calculate the post-blowing time and post-blowing feeding quantity.Both of them are of great significance for saving auxiliary materials and oxygen and improving the finishing point.Finally,based on the object-oriented method,combined with the on-site production requirements,this thesis designs and implements the independent control program system of the converter steelmaking based on the expert system.In the 268 furnace times put into operation,the double hit ratio of carbon temperature reached82.4% for the furnace times fully controlled by the system,while the double hit ratio of carbon temperature was only 58.9% for the furnace times without automatic control.The production practice shows that the system achieves higher control effect,reduces production cost and effectively improves product quality stability.