Research On Automatic Control Of Coal Blending In Coal Preparation Plant

With the advancement of coal mining technology,coal production is developing in the direction of automation and intelligence,and coal mining methods are also changing from extensive to intensive.Due to the various types of coal in various places,coal blending is of great significance in order to meet the demand for coal quality in different occasions,save coal resources,and reduce production costs.The traditional manual coal blending system,due to customers' requirements for the calorific value of the product coal,leaves a certain margin in the calculation of the blending sheet and on-site operations,resulting in waste of high-quality coal,which greatly affects the economic benefits of the coal mine.Problems with equipment cannot be discovered in time.The coal blending efficiency is low and the labor intensity of workers is high.However,the coal blending system has many large lag links,electromagnetic interference from field equipment causes model instability,and product coal quality dynamic monitoring equipment is not perfect.It is difficult to accurately quantify coal blending.Therefore,it is urgent to develop a safe and reliable coal blending automatic control system.This article first analyzes the original system,masters its field equipment,control principle and technological process,and summarizes the existing problems.Targeted improvements were proposed,and the control principle and process flow of the new system were designed.Based on the technological process,the equipment to be added was selected,the functions and characteristics of the main equipment were analyzed,the bus system was laid out,and the original hardware equipment was summarized and counted.The peripheral program of the coal blending control system and the loading link subroutine were written,and the main program,safety monitoring program,data processing program and delay processing subroutine of the coal blending link were designed,and the coal blending process was realized from the coal bunker to the completion.Control of exportable commercial coal flow.The main program of the loading link and the railway loading program are designed,and the process of commercial coal from the loading building to the coal carriage is controlled.Through the analysis of the coal blending system model and the core control equipment coal feeder,combined with the characteristics of the large lag and unstable model of the coal blending system,the Dahlin algorithm,which is commonly used in hysteresis control,is improved.The perceptron is used to correct the time constant of the ideal closed-loop transfer function,and the fuzzy controller is used to correct the learning rate in the perceptron.The performance is analyzed,and traditional coal blending control strategies including discrete PID control,fuzzy PID control and Dahlin controller are compared.The controller adjustment time designed in this subject is between the fuzzy PID and Dahlin controller,and the overshoot is attenuated.Ratio is better than fuzzy PID controller,suitable for coal blending control systemDesigned for the detection and monitoring system in the coal blending process.First of all,the network structure is analyzed,combined with the safety regulations and operating procedures in the factory,a multi-machine monitoring system based on WinCC is built through the ring network connection.The login interface,main interface,ratio and loading record interface,parameter setting interface,alarm interface,trend display interface and database interface are designed.The SQL database is used to record the proportioning list and loading data,and the We Chat applet monitors the system in multiple locations.The control system and hardware equipment were configured,and data collection and on-site debugging were carried out on the spot.The results show that the accuracy of the coal blending process is significantly improved on the basis of ensuring stability compared with the original system manual control.The fluctuation of the blending ratio and ash curve does not exceed 2% during stable operation,and the ash value can be stably controlled below the preset ash content.0.5%.Stable operation can also be realized during the loading process,which improves the level of system automation.