High Integrity Protection Systems for Flare load （高完整性保护火炬系统负载）.pdf

HIGH INTEGRITY PROTECTION SYSTEMS (HIPS) FOR FLARE LOAD MITIGATION Angela E. Summers, Ph.D., P.E., President, SIS-TECH Solutions, LP “Flare Reduction with High Integrity Protection Systems (HIPS),” ISA EXPO 2003, Research Triangle Park, NC: Instrumentation, Systems, and Automation Society, Houston, Texas, October 20-23, 2003. The American Petroleum Institute (API) and American Society of Mechanical Engineers (ASME) provide criteria for the protection of vessels and pipelines from excess pressure. In conventional design, a Pressure Relief Valve (PRV) is used as the primary means of protection, and a flare is used to safely combust the gases relieved during an overpressure event. Although conventional, the use of a PRV is sometimes an unattractive proposition, particularly where the pressure relief involves a large flare load. API 521 and Code Case 2211 of ASME Section VIII, Division 1 and 2 allow the use of an SIS in lieu of a PRV as long as the SIS meets or exceeds the protection that would have been provided by the PRV. As an SIS, the design must follow the safety lifecycle provided in the United States standard ANSI/ISA 84.01-1996 or the international standard IEC 61511. The required risk reduction results in the need for high SIS safety availability; therefore, these systems are often called High Integrity Protection Systems (HIPS). Code Requirements Until August 1996, ASME required the installation of pressure relief devices on all pressure vessels for compliance with Section VIII, Division 1, para UG-125(a) Section VIII, Division 2, para, AR-100. With the approval of ASME Code Case 2211, ASME acknowledged that overpressure protection should be provided by the most appropriate engineered option. The Code Case is intended to enhance the overall safety and environmental performance of a facility. It is not intended as a blanket approval of the operation of pressure vessels w