Construction Method Of Process Risk Early Warning Model During Startup And Shutdown Of Petrochemical Units

The startup and shutdown process of petrochemical units is an extremely important link in the petrochemical production process.There is a high probability of serious accidents such as fires,leakages,and explosions during the startup and shutdown processes.The main reason is that the startup and shutdown processes usually involve a large number of operation steps and complex procedures,the operators are prone to commit errors;the devices have problems such as design and manufacturing defects,improper use and operation,or poor maintenance and management,these problems may lead to leakage of hazardous chemicals.;moreover,most petrochemical units run under extreme conditions,such as high temperatures,pressures,and speeds.Frequent accidents in the startup and shutdown processes greatly affect the normal production of petrochemical units.Once a fire,leak,or explosion accident is triggered,the consequences will be extremely serious,threatening the surrounding buildings,equipment,personnel,and bringing huge economic losses to the enterprise.When signs of abnormal conditions are found,accidents can be prevented and controlled if effective measures are taken in time.Therefore,it is very important and necessary to conduct research on the process risk early warning during the startup and shutdown of petrochemical units.However,there are still many problems in the process risk early warning methods and technologies during the startup and shutdown of petrochemical units that need to be studied in depth.Misoperation risk analysis methods are not perfect enough,especially the step reversal analysis method has ineffective means and a large workload;the proportion of gas leakage accidents is high,and the consequences are serious,but the model for real-time quantitative calculation of gas leakage and prediction of accident consequences is lacking;the analysis and investigation reports of the existing accidents have not been fully summarized,and it is difficult to apply to the actual accident prevention and control.In order to prevent major accidents during the startup and shutdown of petrochemical units,this paper studies the construction method of process risk early warning model during the startup and shutdown of petrochemical units.The main contents are as follows:(1)The method of misoperation risk analysis and early warning model establishment in the startup and shutdown processes was studied.Firstly,the misoperation forms were summarized and classified.Combined with Hazard and Operability Analysis(HAZOP),the Misoperation-Hazard and Operability Analysis method was developed to conduct a comprehensive risk analysis of operation error,step omission,and step reversal,identify the most risky misoperation behaviors,determine the key monitoring parameters,and propose recommended measures under abnormal situations.Based on the risk analysis result,an early warning knowledge database was established to provide early warning knowledge.Furthermore,misoperation judgment rules were formulated to identify misoperations.Finally,combining real-time status monitoring,early warning knowledge database,and misoperation judgment rules,a misoperation monitoring and early warning model was constructed,which can provide a theoretical support for the construction of the misoperation monitoring and early warning module.(2)The method of leakage accident consequence prediction and early warning model establishment in the startup and shutdown processes was studied.Firstly,factors such as leakage caliber,leak height,wind speed and atmospheric stability were analyzed to determine the main factors affecting the consequences of the leakage accidents.Taking the main influencing factors as variables and comprehensively considering other influencing factors,the UDM model was used to simulate and calculate the consequences of accidents such as diffusion,fire,and explosion after the device gas leaks.Through regression fitting of the simulation results,the coupling relationship between the main influencing factors and the consequences was obtained to establish the prediction model of the consequences of leakage accidents,and to verify and revise it.Finally,combining the leakage accident consequence prediction model with actual production operation monitoring,a leakage monitoring and early warning model was constructed,which can provide a theoretical basis for constructing a leakage monitoring and early warning module.(3)The method of analysis and prevention of startup and shutdown accidents based on accident case information was studied.Firstly,an accident case database was designed and constructed,which is mainly used to record the accidents that occurred during the startup and shutdown of petrochemical units.The LDA model and K-means clustering algorithm was utilized to classify the accidents in the database.And the methods of word frequency statistics and probability calculation were adopted to unearth the factors that need to be focused on accident prevention.By matching and combining these factors,accident risk scenarios can be constructed,and an accident prevention information checklist can be established.Using the checklist,the key factors that are likely to cause accidents can be identified pertinently.Based on the inspection results,corresponding protection strategies can be formulated,which can provide an effective accordance to construct an accident prevention inspection module.(4)The construction method of process risk early warning system during the startup and shutdown of petrochemical units was studied.Based on the misoperation monitoring and early warning model,leakage monitoring and early warning model,and accident prevention information checklist,the misoperation monitoring and early warning module,leakage monitoring and early warning module,and accident prevention inspection module were built by KingSCADA software and SQL Server database to develop a process risk early warning system during the startup and shutdown of petrochemical units.The system can realize real-time continuous monitoring,accident risk early warning,emergency rescue guidance of misoperation and leakage accidents,as well as the inspection and prevention of accident risks,which can provide a technical basis for the operation guidance,accident risk early warning,and emergency rescue of petrochemical units.Based on the knowledge of risk analysis,simulation,condition monitoring,accident early warning,emergency guidance,and other knowledge,this paper proposes a construction method of process risk early warning model during the startup and shutdown of petrochemical units.The method can provide early warning of accidents and guide the operation of the device,thereby ensuring the safe and stable operation of the startup and shutdown processes,and improving the intelligence and autonomous health level of petrochemical units.