PRV Stability Assessment of NGL Facility Case Study


The Challenge

In order to ensure compliance with the OSHA PSM standard, an oil and gas business retained ioMosaic to do a stability evaluation of six pressure relief valves (PRVs) identified to have inlet pressure drop in excess of 3% of the set pressure.

Their current operations include 192 MMBbls of NGL storage, NGL Import/Export terminals on the Houston Ship Channel with capacities of up to 10,000 Bbls/Hr (import) and 5,000 Bbls/Hr (Export), 19 NGL and propylene fractionators with capacities of up to 439 Mbpd of NGL, 65 Mbpd propylene and 116 Mbpd isomerization, and natural gas processing of up to 6.3 Bcf/day.

OSHA 29 CFR 1910.119 Process Safety Management (PSM) requires, under the Process Safety Information (PSI) element, that employers compile information pertaining to the equipment in the process, including relief system design and design basis.

Our Approach

ioMosaic prepared the PRV stability analysis and documentation using our software Process Safety Office® SuperChems™. The client provided the stability calculations of the relief conditions, isometrics and compositions. Our advanced tools were used to estimate key pressure relief valve (PRV) parameters and to estimate the performance of the PRV. Three of the six installations were found to perform in a stable manner despite the slightly excessive inlet line losses. The force balance was positive and acoustic interactions were found to result in a stable installation.

Process Safety Office® SuperChems™ executable files for each of the relief devices, a comprehensive report explaining the evaluation results and methodologies, and a discussion list of the study's findings and concerns, along with alternative mitigation strategies, were all part of the project deliverables.

The Benefits

ioMosaic saved our client over $100,000 by demonstrating stable PRV performance and eliminating the need to modify the piping installation. The stability analyses identified potential opportunities to improve the performance of three of the six relief devices. Efficient project execution, detailed reports, and high-level summaries ensured our client had the appropriate knowledge and necessary to make risk-based decisions in a timely fashion.

Learn More

Our mission is to help you protect your people, your plant, your stakeholder value and our planet. To learn more about how we can help you manage risk, call us at 1.844.ioMosaic.