Research And Application Of Ash Automatic Control System For Dense Medium Separation Of Clean Coal

As China’s 14 th five year plan and the outline of long-term goals for 2035 put forward the requirements of adhering to innovation driven development,comprehensively shaping new development advantages,accelerating the development of modern industrial system,consolidating and strengthening the foundation of the real economy,promoting green development and promoting the harmonious coexistence between man and nature,coal,as the primary energy with the largest consumption in China,the development of the coal industry must meet the requirements of innovation Modern and green development requirements.The same is true for coal preparation plants.In recent years,major coal preparation plants have actively complied with the trend of the times,followed the pace of innovation,and continuously promoted the intelligent development process of coal preparation plants.As a necessary link of coal washing,the intelligent development level of dense medium separation represents the intelligent development level of the whole coal preparation industry to a certain extent.At present,the operation of the control actuator for heavy medium separation has been basically automated,and the automatic control of heavy medium separation has been developed to a certain extent.However,in the actual production process,due to the fluctuation of raw coal quality,improper operation of staff,mismatch of process and equipment and other reasons,it will more or less affect the control of dense medium system,and eventually lead to the unqualified ash content of clean coal products and affect the product quality,which is not only inconsistent with the green development concept,but also brings huge economic losses to the coal preparation plant.Therefore,in view of the above problems,how to realize the automatic control of ash content of clean coal in dense medium separation has become the key problem for the intelligent development of coal preparation plant.Literature review shows that the research on the automatic control system of dense medium suspension density has been relatively mature.The control system based on PID and fuzzy control can well realize the automatic control of dense medium suspension density,and has been widely and mature applied in major coal preparation plants.For the ash automatic control of dense medium separation clean coal,that is,ash back control,its intelligent development level is far from meeting the requirements of the actual production process.The essence of the ash back control system is that the product clean coal ash produced under the control of the system is used as feedback input to guide the automatic update and setting of the density of heavy medium suspension on the basis of inputting the target value of clean coal ash in advance,without manual input.This requires that on the basis of mature and reliable density control system,reliable clean coal ash output is also required as feedback value.Moreover,as a system with large lag and inertia,the dense medium separation system can ensure the stability and reliability of the system by timely feedback of cleaned coal ash.Firstly,this paper puts forward the overall scheme design,introduces the principle and process of dense medium separation,constructs the overall framework of the ash automatic control system of dense medium separation clean coal,and gives the technical roadmap.Secondly,for the automatic control system of dense medium suspension density,the reasons affecting the fluctuation of suspension density are analyzed,the on-site process is reformed,and a composite control model based on PID control automatic water replenishment and multi parameter decoupling fuzzy control automatic shunting and undisturbed switching is proposed.Then,for the clean coal ash back control link,according to the nonlinear and lag characteristics of clean coal ash time series,a prediction model based on EMD-LSTM method is proposed.EMD decomposition method can solve the nonlinear fluctuation problem of clean coal ash time series and reduce the "noise" in the time series.LSTM neural network is suitable for the prediction of delayed time series,It can solve the lag problem of clean coal ash time series;Then SPC analysis is carried out on the prediction data of clean coal ash to further judge whether the prediction data is controlled,so as to further strengthen the stability of the automatic control system.The final closed-loop feedback control is realized by PID and data hybrid drive controller.Finally,the designed ash automatic control system of dense medium separation clean coal is applied to ZTE coal preparation plant.It is realized through the software and hardware system composed of the equipment layer mainly composed of sensors and actuators,the control layer mainly composed of 1769 series PLC produced by AB company,and the management layer mainly composed of server,upper computer,configuration software and MATLAB as the algorithm engine,According to the final effect comparison,the reliability of the ash automatic control system of dense medium separation clean coal designed in this paper has been preliminarily verified in the field industrial application.