Limit-Load Analysis Applications for Expanding Service Envelopes in Vessels with Non Code-Compliant Geometries

摘要

Although the ASME B&PV Code is useful for most vessels, in some cases a vessel's geometry fails to match Code parameters and a U-2(g) exemption is necessary if the vessel is to be rerated. This presentation details the application of Limit Load analysis to extend the service envelopes of two vessels: a Heat Exchanger whose integral channel/tubesheet does not meet Code geometry, and a tower with nozzles that have overlapping areas of reinforcement. Both vessels required an operating temperature increase to meet planned process conditions. The presentation will address various techniques available in Finite Element Analysis (FEA) and the technical challenges associated with each, as well as modeling concerns and paths forward when a vessel might not have complete documentation. The discussion will also touch briefly on similarities and differences between ASME B&PV Code and API 579 for this work.