The Design And Implement Of Ash Automation System For Dense Medium Coal Preparation

Because of its high sorting accuracy and easy to implement automatic control,heavy medium coal preparation is becoming dominant in China’s Coal Coal method.At present,the density control was widely applied in the process of Dense Medium Coal Separation,but the density control belong the intermediate variable control.For Coal user,clean coal’s ash indicators qualified or not is the most important.Therefore,the clean coal ash as a measure of Coal product quality indicators,one hand can protect the coal users on product quality requirements,on the other hand can guarantee the fundamental guarantee for coal preparation technology and maximize economic benefits.So,how to achieve closed-loop control of the clean coal ash is one of the hot issues in the coal preparation process control.The literature review shows that:coal preparation ash is mostly controlled water circuit process,and it is a reference to this thesis.The key issues of Ministry of Coal during eighty-five:in the research of the smalls dense medium preparation system product quality monitoring and control,the ash control effect based on PID have formed obvious oscillation,and manual control effect but better than the automatic control.The reason is that two points,the first,the research is not enough for the statistical process characteristics of ash in the coal preparation process.In fact,the production process of coal preparation,the clean coal ash has a stochastic volatility,to automatically control under an ash value is not consistent with the objective law of random fluctuations in the ash itself.The second,control algorithm is not appropriate,we all know,coal preparation process from the ash back to the control density to adjust the water circuit is typically a nonlinear,large inertia and large time delay process,and not a simple single-input single-output process,using a simplePID is unable to obtain satisfactory results.For this,focused on the statistical properties of the coal preparation process ash fluctuations,the thesis proposed the new ideas of Dense Medium Separation ash closed-loop control based on statistical process control.For large inertia and large time delays of the coal preparation process,drawing on expert systems and fuzzy control theory and technology,expand research and exploration of the Dense Medium coal preparation ash closed-loop control,in order to achieve a breakthrough in this thesis.The thesis analyzes the system parameters affecting clean coal ash of the Dense Medium Separation,useing the control ideas of clean coal ash back to the control suspension density,this is to say,the ash set value as control targets by regulating the suspension density in order to achieve the ash to set requirements programs.To achieve the above program,the key lies in two aspects.The first is the stochastic volatility characteristics of the ash of the coal preparation process,while the clean coal ash detection is essential for control.The second is the density control high efficiency or not greatly affect the ash back to the control.Only the reasonable control of the density,ash back control only to achieve feasibility.Structure,characteristics and influence factors of existing plant online ash analyzer have analyzed in thesis.Based on introducing statistical process control theory,due to the problem of random wave characteristics of clean coal ash,the method of using statistical process control(SPC)theory to dispose and decide ash online value was proposed.Through analysing and choosing X-MR chart of SPC to control quality management.First,utilizing MR chart to analysis ash online value with the purpose of reducing the errors.Second,establishing the XSD control chart with ash set data for the center line,input ash online value to chart and judge process control.The emplement of Dense Medium Separation ash back control is based on Dense Medium suspension density to be adjusted.So Dense Medium suspension density control system perfect or not is the key to adjust the magnitude of the achievement of the ash back control.The thesis briefly described the characteristics and shortcomings of the existing density control system and developed a Dense Medium suspension density automatic control system based on the PID + Fuzzy complex control system.The system realizes the high-precision control of density,automatic replenishment and automatic Spilt flow Bumpless Transfer.It extended the range of density regulation,and laid a solid foundation for the ash back control.For the Chengzhuang double system mutual disturbance characteristics,the thesis considered the level difference on the coupling action of the system and designed its decoupling.The single-density control strategy has been improved and optimized.The optimization system obtained better industrial application effect in nearly a year of running Chengzhuang Coal Preparation Plant.From the control sense,the mathematical model of ash control system is more complex.Through the analysis on the characteristics of the ash automatic control system,the thesis presents a composite closed loopfuzzy control system based on expert rules and SPC.Ash control system framework and the model is built,the ideas and steps of the control model is given,the control key and difficult points in the control system is solved,it laid the foundation for the true sense of the clean coal ash control.Based on reasonable configuration and optimization of spot sensor and actuating mechanism,PLC program design and WINCC software were developed with the configuration,so ash automatic control system of Chengzhuang Coal Preparation Plant was built.The system was used in type approval test on the spot and the results showed that control system can achieve ash closing loop control.During the process,no significant shock appeared.Ash was controlled stably in the XSD control chart with ash set data for the center line and the density was rationalized,so that the desired results were achieved.