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Propane Frozen Earth Storage Decommissioning

Award winning decommission of subsurface propane cavern

  • 42K

    CY of Grout

  • 60K

    CY of Sand

  • $15M

    Total Cost

  • Delaware, DE

    Delaware, DE

Our team safely decommissioned a leaking propane Frozen Earth Storage facility in an active refinery

The Frozen Earth Storage (FES) was commissioned in 1966 as a refrigerated storage cavern for liquid propane at Delaware’s only propane refinery. However, incompatible design features and unique subsurface conditions resulted in persistent, uncontrolled, and dangerous propane leaks and the FES was scheduled to close by 2010. Our team was responsible for decommissioning the FES to terminate fugitive emissions from the cavern—a critical mission threatened by flammable gas hazards and unstable ground conditions.

The FES was 165 feet wide, 128 feet deep, and had a capacity of 495,000 barrels. Three concentric rings of 250 vertical freeze-pipes were part of a closed-loop propane refrigeration system that kept the subsurface cavern walls frozen and the cavern under design pressures. To reduce risk, our team operated during the coldest months of the year when the propane’s reaction potential would be less volatile. 

The project would cost $15 million and included process engineering, thermodynamic analysis, piping design, and geotechnical studies. Our team developed a decommissioning plan before drafting all geotechnical and process designs. The results demonstrate how unique skill sets can coincide to safely complete a project and build a sustainable future together.

At a Glance

Offices
Award
2012 ENR Best Industrial/Manufacturing Project

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