Research On Real-time Healthy Assessment And Maintenance Decision Making Of Centrifugal Compressor

The centrifugal compressors are used as the core equipment for compressed gas in the chemical,petroleum and other industrial fields.With the advancement of modern technology and the increasing demand for diversified production,the requirements of the health,stability,efficient operation and predictable maintenance of centrifugal compressors are getting higher and higher,and the healthy and efficient operation of large centrifugal compressors played vital roles in industrial production.Unplanned downtime of centrifugal compressors would cause a lot of economic losses.Vigorous development and application of condition monitoring technology can prevent failures in advance.Most of the fault repairs of centrifugal compressors still used planned maintenance or after-the-fact maintenance,the disadvantage of the planned maintenance period is too long to ensure the health of the centrifugal compressor unit,and if the cycle is too short,it would cause a lot of economic waste.According to statistics,at present,the major petrochemical enterprises(Sinopec,PetroChina,CNOOC)in China currently have about 4,000 large-scale compressor units(200KW or more)in service,with a design power of about 9 million kW.If the in-service renovation project is implemented,the operating efficiency of the compressor unit will be increased by 10%,and the annual energy saving will be 7.6 billion kWh,saving 4.6 billion yuan.In this paper,the real-time health and maintenance decision of centrifugal compressor is studied.Based on the centrifugal compressor failure case,knowledge and experience learning,and statistical analysis method,the centrifugal compressor health assessment model is constructed.Based on the failure mode and consequence analysis of centrifugal compressors and the health status level,a dynamic risk assessment model for centrifugal compressor operation reliability was constructed and corresponding maintenance decisions were made.Based on mathematical analysis and modeling coupling,the significant influencing factors of centrifugal compressor energy consumption were identified,and the energy consumption influencing factors were evaluated and verified.The calculation model of centrifugal compressor efficiency based on motor was constructed.The main research contents of the thesis are as follows:(1)Research on construction of centrifugalcompressor health assessment model.Based on typical fault cases such as surge,misalignment and rubbing of centrifugal compressors and operating data under normal conditions,the centrifugal compression machine health status assessment model is developed by using knowledge and experience learning,statistical analysis of data,etc.,and using the correlation function,condensing function and spectral distance function,the centrifugal compressor health status is divided into four criteria:excellent,good,monitoring operation,recommended shutdown.Based on the migration learning method,the accuracy and feasibility of the health assessment model were verified by the NSFI/UCR rolling bearing No.l and No.2 full life cycle experiments and a company rotor imbalance fault case.(2)Research on dynamic risk assessment model construction and maintenance decision of cntrifugal compressor.The centrifugal compressor system was divided into seven parts based on GB/T20172-2006;the high-risk parts of the centrifugal compressor are determined through the failure mode and consequence analysis of the centrifugal compressor;based on the real-time health status of the centrifugal compressor,The reliability dynamic risk assessment model of centrifugal compressor operation is constructed and a centrifugal compressor maintenance decision model is developed.(3)Research on Identification of Major Influencing Factors of Energy Consumption of Centrifugal Compressor and Construction of Efficiency Calculation Model.Based on the rough set theory,the attribute of energy consumption is reduced.The network analytic method is used to evaluate the influencing factors of energy consumption.The two-stage centrifugal compressor is modeled by Aspen plus software,and the influence of different factors on energy consumption is obtained.A calculation model for the efficiency of a centrifugal compressor driven by a motor was constructed.Based on the actual measurement data,the real-time operating efficiency of a centrifugal air compressor at a plant level was calculated.