Reliability Data Processing In The Application Of Functional Safety Assessment Research

In recent years,with the enlargement of the scale of petrochemical enterprises,the improvement of automation and the increase of process control system,the safety instrumented system is becoming more and more extensive.At present,the design of the safety instrument system is not standard and the configuration is unreasonable and so on,and there are some hidden dangers.Therefore,it is very important to perform the functional safety assessment of the safety instrumented system.In China,we actively promote the safety assessment of safety instrumentation system at the same time,but also faced with the lack of basic reliability data.The collection and processing of reliability data is the focus of the current work.Based on the reliability data collected from the specific equipment of the petrochemical enterprises,this paper describes the processing methods of the site reliability data in the functional safety assessment of the equipment.Aiming at the situation of large sample failure data,small sample failure situation and no failure data in the process of collecting individual enterprises,the estimation of the failure rate is carried out according to the different mathematical model.In this paper,we use the Bayesian method to estimate the failure rate by using the classical estimation method,the small sample data and the no sample data for the large sample data,and obtain the parameter estimation of the risk failure.According to the failure data collected on site,the failure mode,impact and diagnostic analysis(FMEDA),the proportion of safety failure,the proportion of dangerous failure,and the ratio of diagnosable and non-diagnosable safety failures and hazard failures were carried out.,And finally into the engineering practice commonly used reliability diagram to verify the verification.Finally,taking the field data of the sulfur recovery unit as an example,the failure rate of the three subunit parts of the safety instrument system and the estimation of the relevant parameters are carried out.The field estimation efficiency and the database failure rate of the industrial database are compared and analyzed.The results of the SIL evaluation of the validation model and the SIL target are compared.The result shows that the data processing scheme adopted by us is in accordance with the expectation and can provide some safety assessment for the safety of the instrument system.