Pressure Relief Valve Design Evaluation

Project Synopsis

Refinery pressure relief valve evaluation for determining relief valve capacities at current process throughput rates.

Project Summary

REFINERY PROCESS RELIEF VALVE EVALUATION AND DOCUMENTATION AUDIT

Process Engineering Associates, LLC (PROCESS) was contracted by the client to conduct a comprehensive audit of refinery relief valve documentation and to perform a technical evaluation of selected relief valves for the purpose of determining relief valve capacity relative to current process throughput rates.  Project elements included:

• Refinery relief valve design information and process documentation review
• Relief valve design information and process documentation field verification
• Refinery process information review
• Heat and mass balance and vapor-liquid equilibrium calculations preparation
• Relief valve relief requirements and capacities evaluation.

PROCESS reviewed project engineering, maintenance, and inspection files to locate available relief valve design information.  PROCESS directed technicians who field-verified P&IDs and other process documentation sources to confirm and/or correct the process documentation and existing relief valve locations, applications, and design information.  PROCESS then collected existing production unit mass and energy balance information, vessel pressure ratings and sizes, and additional engineering information required to execute the relief valve requirements and capacities evaluation.  Additional heat and mass balance and vapor-liquid equilibrium calculations were performed by PROCESS as necessary to complete the throughput information required for the relief valve evaluation.  PROCESS then used proprietary in-house computer programming technology to evaluate the relief requirements for identified potential pressure relief scenarios, including:

• Blocked liquid and/or vapor flow
• External fire
• Loss of cooling
• Loss of power
• Gas blowby
• Malfunctioning control valve
• Heat exchanger tube failure
• Reverse/misdirected flow
• All other pressure relief scenarios identified during the course of the evaluation.

Finally, the same computer technology was used to calculate the required size for relief valves determined to be undersized for the current applications.

Relief valve evaluations were performed for 77 selected valves for the following refinery process units:

Industry Type

• Petroleum Refining

Utilized Skills

• VLE calculations
• Heat and mass balance
• Computer process simulation
• Pressure relief valve (PRV) and pressure safety valve (PSV) sizing
• Comprehensive relief valve evaluation