Case Study: Repeated Flange/Gasket Blow-Outs on a Dehydrator Vessel - A Multi-Factor Approach to Solving Flange Problems

For: A dehydrator vessel, operating in cyclic pressure and temperature service, was experiencing repeated gasket blow-outs on a regular frequency. An investigation was performed to determine the likely causes of the repeated failures, and to quantify the potential benefits from a series of possible modifications. This case study will discuss the most likely causes that were determined for the repeated failures. Since several factors were evaluated, this presentation will serve as a useful example of the wide range of possible factors and solutions to bolted flange joint leakage issues. Some of these include: - Bolt pre-load - Gasket selection - Bolted flange joint configuration - Insulation on the flange - Washers - Lubricant - Assembly procedures The bolted flange joint in question was situated in the off the west coast of central Africa, in the country of Equatorial Guinea. The remote location of this installation presented some specific challenges. Some of these challenges may be relevant to Alberta's remote fly-in/fly-out facilities.