Phased Rehabilitation Returns Sulfur Pit to New Condition
A critical sulfur pit in a United States refinery originally built in the 1970’s had begun to show signs of deterioration in the roof and water ingress was impacting the operating temperatures of the pit. The client wanted to restore the pit to like-new condition, update the mechanical systems and ensure that the repair design would provide a 20+ year service life.
The project team of STRUCTURAL and STRUCTURAL TECHNOLOGIES was selected to design and build a solution to deliver the desired service life of the sulfur pit. The team’s solution was to phase the repairs, first stabilizing the soil around the exiting pit to slow moisture intrusion and to provide strength for the second phase of reconstructing the pit in the existing footprint during a scheduled turnaround.
After a condition assessment, phase 1 took place in a scheduled turnaround where the soil surrounding the pit was stabilized. Utilizing an engineered solution of specialized chemical grouts, a protective grout curtain was installed around the perimeter of the pit in several layers. This curtain diverted ground water away from the sulfur pit to improve the efficiency of the existing pit until the next scheduled turnaround, while also improving the soil stability for the second phase of the project.
The project team built a detailed design in preparation for the second phase of the project, to be executed in a 21-day window of a scheduled plant turnaround. The team designed all the cast-in-place concrete elements of the pit, including the base slab, sump areas, walls and roof design. The team also provided design and fabrication of all mechanical elements to tie the improved sulfur pit to the unit’s process.
STRUCTURAL and the project team carefully planned each step of the construction process resulting in a project that was delivered on time and with zero safety incidents.