Application of RBI for Pressure Relief Valve In-service

Pressure relief valves of pressurized equipment as an important physical barrier, play a crucial role to protect pressure equipment, its reliability of performance and operation is directly related to the safety of the plants and personnel. From the point of view of Chinese laws and regulations, it is generally required that the in-service pressure relief valve would be calibrated at least once a year. However, that is in conflict with the demand of large petrochemical plants to gradually implement the 5 to 8 years long period operation. Based on risk assessment technology, the failure mode of the pressure relief valve was analysed, and the probability of failure and the consequence of failure for the pressure relief valve were calculated by use of quantitative RBI method. The criterion was proposed to determine risk-based calibration cycle of the pressure relief valve. Through the reasonable application of risk assessment technology for the pressure relief valve, it could meet the long period operation of the petrochemical plants under the condition of ensuring the normal operation of these valves.