Study Of Energy Analysis Evaluation And Energy Efficiency Optimization For Complex Distillation Process

Separation process of methanol to olefin production is an important process route for obtaining important low-carbon olefins such as ethylene and propylene.The technological process is mainly based on rectification system,including multiple separation units and large energy consumption in the process.It has great potential for improvement in energy conservation and consumption reduction.In this paper,based on a comprehensive understanding of the technical route and process mechanism of the separation process of methanol to olefin production,the exergy analysis and evaluation method is used to analyze the energy consumption of the methanol to olefin production,identifying the weak links in the process energy use,and establishing the soft sensor model for the distillation tower.Efficient soft measurement model,carry out optimization research.The main research content is as follows:(1)By systematically reviewing the literature about the exergy analysis methods and energy efficiency optimization,the research progress and status of the exergy analysis method are systematically reviewed;and the soft sensor of exergy efficiency modeling and optimization are reviewed.The work provides ideas and theoretical support for the research work of this article.(2)The exergy analytical model of the distillation process is establishing.First,a simple energy division is performed for distillation tower,and the exergy balance equation is obtained and the specific calculation methods are elaborated.Proposing exergy loss,exergy efficiency and exergy loss rate as energy consumption evaluation standard.(3)On the background of separation process of methanol to olefin production,the research on the exergy analysis evaluation and energy efficiency are carried out.Firstly,the Aspen plus was used to simulate the whole process and the Aspen plus simulation results were compared with the actual situation.The results show that the flow rate,component concentration,and temperature values of the simulated separation units at the top of the separation unit and the bottom of the column reactor are basically the same as the actual values,thus demonstrating the accuracy of the process simulation.Through the acquisition of related thermodynamic parameters in Aspen,combined with the exergy analysis method,the whole process and the energy analysis of each separation unit were analyzed.The results show that the minimum efficiency of the ethylene distillation unit is 50.4%,and the maximum loss rate is 37.6%.The distillation unit is the weak link of process energy.Analyzing the causes of large energy consumption and propose feasible improvement measures and pointing out the direction for follow-up optimization research.(4)An integrated artificial neural network based on Bagging algorithm was used to establish the exergy soft-sensing model and energy efficiency optimization method for distillation process.Firstly,based on exergy efficiency and the key operation parameters was determined.Then,a single-artificial neural network model and an integrated artificial neural network were established.The prediction performances of the two models were compared.The results show that the latter has higher prediction accuracy.Finally,with optimization exergy efficiency as the optimization goal,under the condition of satisfying product quality constraints,the operating conditions under the best exergy efficiency were obtained,and the optimized results were verified with Aspen plus.The results show that under the operating conditions,the exergy effectiveness has been significantly improved.