Development Of Pulse Jet Control System For Purifying Fume Of Aluminum Electrolysis Based On Case-based Reasoning

With the rapid development of China's electric power,steel,aluminum electrolysis and other industries,the emission of flue gas has caused the continuous deterioration of the environment in many places,seriously affecting People's Daily life,and jeopardizing people's physical and mental health.At present,the aluminum electrolysis flue gas is purified mainly by dry method,and the bag filter is used for ash removal.Compared with other dedusting equipment,pulse jet bag filter has a great advantage in dedusting efficiency.As an efficient dedusting device,it is widely used.However,the pulse jet dust collector needs to control the gas injection interval through the electromagnetic pulse valve during its operation.At present,the traditional fixed timing and constant pressure difference are commonly used in aluminum electrolysis plant to control the spray interval.However,this method is difficult to adapt to the constantly changing field conditions,and may also lead to excessive discharge of pollutants and increase in the consumption of fresh alumina and other problems.Under the background of energy conservation and emission reduction,the traditional control method is facing a great challenge.Therefore,it is particularly important to develop a control system that can automatically adjust the pulse injection interval in real time according to the operating conditions of dust removal.In this paper,based on the upgrading project of the flue gas purification system of an aluminum electrolysis plant in China,the control model of pulse injection and blowing interval is established,and the control system of pulse injection and blowing interval based on case-based reasoning is designed and developed,and the experimental test and application analysis of the control system are carried out.The main work is as follows:(1)The control model of pulse injection interval for flue gas purification was established.Based on the analysis of the pulse injection process and the difficulties in mathematical modeling,a pulse injection control model for the flue gas purification of aluminum electrolysis was established based on the data-driven method.Since the injection interval is the most important control variable in the process of pulse injection,the accurate control of it is very important for the process of pulse injection dust removal.Based on the analysis of the disadvantages of the traditional control methods of timing and constant pressure difference,this paper proposes a control algorithm of pulse injection interval based on case-based reasoning.The results show that the weight assignment method and case correction method have good performance in the control of pulse injection interval.(2)The control system of pulse injection interval is designed and developed.According to the process of pulse jet cleaning,a jet control system is designed which consists of three layers: electrical execution layer,distributed control layer and intelligent monitoring management layer.Among them,the intelligent monitoring management realizes the intelligent control of the spraying interval and the collection and display of key parameters in the pulse spraying dust removal process.The distributed control layer adopts AB series PLC and ring Ethernet structure.Its main functions include data processing,network communication,logic control of execution equipment,etc.It is the link between the execution layer and the monitoring layer.The electrical execution layer provides real-time data and execution of control commands under different working conditions for the intelligent monitoring management layer and the distributed control layer.The spray control system adopts MATLAB,Eclipse(Java language development platform),Factory Talk View Studio upper computer software and SQL Server 2008 database to realize the system development.(3)Experimental testing and application analysis.The experimental test of the case-based reasoning(CBR)injection control system was carried out based on the data collected from an aluminum plant in China,the results show that the method is more effective than the traditional fixed frequency control method.By comparing with the traditional fixed frequency-setting method,it is proved that the CBR algorithm can effectively reduce the emission concentration of HF gas and dust,and stabilize the pressure difference between the inlet and outlet of the dust collector.The system is easy to operate,and it can calculate the best spraying and blowing interval time in real time,and transmit it to the upper computer through OPC communication,so as to realize the intelligent control of spraying and blowing.To sum up,the system has certain actual application value.