Common "Design Flaws" Identified during Pressure Relief System Analysis

Common “design flaws” identified during a pressure relief system analysis.

It is the goal of a pressure relief system analysis to identify possible gaps in a pressure relief system. In many oil and gas refining and petrochemical plants, it's common to encounter certain “design flaws” which can lead to overpressure scenarios where the system is not adequately protected.

Within these design flaws there are a few which frequently occur, regardless of the process.  These can be just simple mistakes or related to consideration not being given to the whole system as part of the design.  This paper will focus on five common design flaws:” unusually large bypass valves around a (smaller) control valve”; “liquid head between relief device and equipment being protected”; “how does the suction of the feed pump behaves during the scenario”, “tube rupture can affect an entire system and not just the exchanger”; and “common API 650 tank concerns”.  For each “design flaw” a few common mitigations will also be discussed.

The goal of this presentation is not to discuss the issues in detail, but rather just bring to the industry's attention a few concerns being frequently identified.