Research On Key Issues Of Process Management And Control In Hydrogenation Unit Level CPS Platform

Transforming and upgrading traditional industries and developing intelligent manufacturing has become an important development trend of manufacturing industry,which is driven by the new generation of information and communication technology.The goal of the petrochemical smart factory is excellent operation,and the cyber physical system(CPS)is built to improve the operation and management level of the plant according to three main lines which are "the whole process integration optimization,the whole process integrated production control and the life cycle integrated asset management".The construction of petrochemical enterprises CPS around the three main lines is now integrated and developed by the domestic and foreign industrial software.There are difficulties in localization or inaccurate calculation of relevant professional industrial software.Moreover,in the early stage of construction,some typical issues that cannot be solved around the three main lines have emerged,such as in the aspect of the integrated optimization of refining and chemical production,the key to achieve accurate prediction of planned production and guide production is to establish accurate and real-time device input-output model,rather than the approximate mechanism model or empirical data model which are applied,currently;In the process of production control,at present,the indicators for controlling binary products are controlled based on periodic tests.After detecting the product quality deviation,the unqualified products have been generated for some time,and the detection lag may affect the product quality.In this case,it is necessary to establish a mathematical model which can be used to predict the binary product quality index.In the aspect of asset management in the whole life cycle,it mainly guarantees the stable operation of the equipment through the alarm of equipment operation parameters or regular maintenance.There are many problems in this method,such as over maintenance of equipment or unscheduled shutdown caused by equipment problems.Therefore,the key to ensure the stable operation of equipment and avoid unscheduled shutdown is to establish accurate model and evaluate the equipment online in time.Meanwhile,hydrogenation unit is an important part of refining process.The intelligent operation of hydrogenation unit is becoming more and more important for upgrading the structure of petrochemical products,upgrading quality and increasing efficiency.Therefore,the intelligent construction of the hydrogenation unit and high-quality CPS platform,which can be extended to other units in the refining process,will promote the overall construction level of CPS in petrochemical enterprises.Aiming to solve the issues on the construction of hydrogenation plant CPS around the three main lines,such as the lack of accurate reaction process models,binary product quality control issue and equipment status monitoring issue,this thesis establishes corresponding calculation models and proposes corresponding algorithms,applied to a hydrogenation unit in a petrochemical company.Finally,it improves the intelligent level of the hydrogenation unit and provides a reference for the upgrading of the CPS platform in petrochemical enterprises,by integrate the above three models and algorithms into the unit-level CPS platform.The main contents and results of this thesis are summarized as follows:(1)Around the one of the three main lines-"the whole process integration optimization",a hydrogenation reaction kinetic model oriented to input and output of unit is established.In order to build this model,the chaotic particle swarm genetic algorithm joined with the chaos perturbing(DCPSO-GA)is put forward and verified by test function and comparison of calculated results with experimental results of heavy oil cracking.Experimental results show that the proposed algorithm solves the stagnation phenomenon which appears in the optimal,expands the search space of the global optimization and finds the global optimal solution with a faster convergence rate,greatly reducing computation load.Applying the above-established method to an enterprise residue hydrotreating unit,the result shows that the method is more suitable for the actual working conditions of the reactor.The square sum of the relative deviations of the calculated removal rate and the actual removal rate of sulfur,nitrogen,and carbon is 0.0017,0.1088,and 0.0587,further improving the accuracy of planning,scheduling and operation.(2)Around the one of the three main lines-"the whole process integrated production control",a prediction and control model for binary product quality is established to carry on the research on real-time prediction of hydrogenation product quality,in order to strengthen integrated control and closed-loop optimization of production process and solve the issues of binary product indicators prediction and timely operation adjustment.To achieve this goal,the sequence of modeling is as follows:firstly,the recursive principal component analysis method is used to extract the principal components of the process variables;then,the logistic regression method is used to predict the qualified probability of the binary quality indicators;furthermore,the quadratic programming method is applied to the predicted unqualified product quality indicators to obtain the least change operation adjustment,so as to improve the qualified rate of product quality.Applied to predict kerosene quality and optimize operating parameters for a hydrocracking unit,the proposed model is validated to predict product quality reliably and rapidly(the quality prediction accuracy rate of doctor test for aviation kerosene reaches 98.5%),improve the qualified ratio effectively(Once qualified rate of aviation kerosene is increased from 70%to 92.6%linked with production execution and control strategies),and enhance the intelligence level of production control.(3)Around the one of the three main lines-"the life cycle integrated asset management",a comprehensive assessment model of running condition for the complex equipment is established to carry on the research on the state prediction and reliability of circulating hydrogen compressor to solve the issue of comprehensive evaluation of operating conditions and early warning,and ensure smooth operation of production.In the view of the long-term stable operation of circulating hydrogen compressor units,an improved fuzzy comprehensive evaluation algorithm is proposed,and an evaluation index system is established.The maximum information coefficient(MIC)is used to analyze the correlation of the index parameters of each evaluation unit,the second-order Markov chain transfer matrix is used to predict the variation trend of the index parameters and calculate the dynamic deterioration degree of independent index parameters,and the fuzzy membership function is used to present comprehensive evaluation of each unit state.The evaluation model is applied to the operation and management of hydrocracking circulating hydrogen compressor in an enterprise.The results show that the method can detect the early hidden trouble ahead of time(10 minutes ahead of the traditional threshold alarm),comprehensively evaluate and predict the operation status of the unit,improve the reliability and operation stability of the unit,and enhance the prediction and early warning ability of equipment management.(4)On the basis of solving three key issues of hydrogenation unit,overall structure and technical route of the petrochemical smart factory CPS platform,the three research results are applied to the CPS platform of the hydrogenation unit,optimizing and improving its technical level.The CPS platform has been greatly improved in terms of production scheduling accuracy,quality prediction,closed-loop control and smooth operation of the equipment,which is of significance for further research on the overall intelligent manufacturing level of the factory.Choosing the application system for evaluating the operation status of circulating hydrogen compressor unit as an example,this thesis designs eight aspects including business process,application function,data processing and model and so on,and integrates the research results into the CPS platform in the way of "platform+application" by use the petrochemical industry internet platform architecture and key technologies such as industrial Internet of things,micro service,big data analysis and processing.It achieves a better performance,and the intelligent optimization cooperation and response ability of CPS in hydrogenation unit is strengthened as well.