Design Of Petrochemical Major Hazards SIS Security Function

Safety standard IEC61508, IEC61511 and State Administration of Work Safety Supervision Decree 40 demanding that different levels of major hazard identification shall be graded and evaluated, and equipped with the appropriate safety monitoring system. Safety Instrumented System is a security monitoring system. It can not only reduce the risk of accidents to a minimum, but also to avoid the occurrence of major accidents in industrial disasters.In the process of security function SIS design, the design of safety integrity level and process parameters selecting are very important. If SIL design is unreasonable,SIS will refusing action and jumping mistake fault; If the number of SIS process parameters selected is unreasonable, will resulting in SIS unsafe and frequently security jumping problems. Also, in petrochemical production, grading and assessment work to identify major hazard on the SIS security function designed is lack of attention.Based on the above issues,the chemical identification of major hazard assessments oil was analyzed.We querying a decade of domestic and foreign databases.Domestic and foreign petrochemical equipment often used in the SIS be counted and classified,generalize 20 SIS and and sixty SIF. The number of SIS process parameters can be selected based on those information and specification GB-T50770-2013. in this way,frequent security parking problems and insecurity problems were solved. On the basis of statistical information, summarizing the information of SIL basic information and security lifecycle information and each SIF logic diagram.Proposing design method based on SIL statistical information to solve the SIS often refuse to operate error and jump car problems. The method of analysis process into four steps: the first step,conducting a hazard and operational analysis, find a big risk covered by the system deviation; the second step, the introduction of risk matrix HAZOP analysis, and using LOPA principle to quantization data,using quantization data obtained SIL, and using RBD model and FTA model to test SIL. Introduced in the verification process Bayes estimation theory to calculate the risk of failure rate, in order to improve the safety integrity level of proven reliability; the third step, statistical-based SIL determined by induction petrochemical equipment species information, statistics and features the same type of equipment empirical data in actual use, provide sufficient data for thecalculation to determine the SIL and the SIL verification. The fourth step,considering the safety integrity level design draw conclusions.Finally, this paper proposes a method used in toluene disproportionation A company unit SIS design.Giving an account of SIL calculation steps and SIL design,and SIL results is given.Finally, a number of SIS based on statistical process parameters be determined in the toluene disproportionation unit.