Safety Integrity Level Assessment Of Complex Safety Instrumented System For Typical Chemical Plant

The safety instrumented system is an important part of ensuring the safety of chemical companies.At present,there are many problems in China’s safety instrumented system.According to the “Guiding Opinions on Strengthening Chemical Safety Instrumented System” issued by the State Administration of Work Safety in 2015,it is pointed out that the existing safety instrumented system mainly includes the following problems: the function identification and risk assessment of the safety instrumented system in its life cycle has not yet been Completely implemented,there is no mature SIL assessment method for the complex safety instrumented system of chemical plants.In the safety integrity level assessment process,the instrument logic structure is blindly verified to calculate the SIL level and the functional safety analysis is neglected.The instrumented does not reach the SIL level,which increases the input cost.In addition,there is no simplified and accurate method for the SIL verification calculation of complex safety instrumented systems,which brings great difficulties to the safety assessment of such systems.In view of the above problems,the specific work and results are as follows:(1)In the safety integrity level assessment of the safety instrumented system,compare the advantages and disadvantages of various evaluation methods at home and abroad,and choose a SIL assessment method suitable for the complex safety instrumented system of domestic chemical enterprises(Method selection includes process hazard analysis method selection,SIL grading method selection,and SIL verification calculation method selection).(2)The selected SIL assessment method is used to evaluate the safety integrity level of the typical complex safety instrumented system-ethanolamine main reaction unit safety instrumented system.Through the practical application of the SIL assessment method,the problem of evaluation is found and the SIL evaluation is carried out.The process is optimized.The optimized SIL evaluation process performs an actual SIL assessment of the methanol saturation tower unit.(3)Aiming at the complicated and inaccurate calculation process of the existing SIL verification method in the SIL evaluation of the complex safety instrumented system of typical chemical equipment,this paper adopts the simplified formula method,the fault tree method considering the common factor failure rate and the Marco.The advantages of the three methods are complementary.A simplified method for the SIL check of the complex safety instrumented system of chemical equipment is proposed.The simplified method is verified.Finally,the influencing factors of the simplified method error are analyzed.Through analysis and comparison,the specific process of SIL evaluation is determined.Through the actual application and improvement of this SIL evaluation process,it is finally determined that this SIL evaluation process is in line with the SIL evaluation of the domestic complex chemical plant safety instrumented system,and a complex combination is proposed.The simplified method of the lock system SIL verification calculation,through the verification comparison,the error is in line with the engineering application.Finally,the error influencing factors of the simplified method are analyzed.The research results in this paper provide a solid theoretical basis for the SIL evaluation of the complex instrumented system of domestic chemical plants.