PSV testing at Northern Lights CCS Facility
The commissioning of the PSVs at Northern Lights, using digital in situ testing, proved to be even more effective than anticipated. The testing was completed ahead of schedule, with no need to dismantle any PSVs.
LEADING THE WAY
Northern Lights JV is a joint venture between Equinor, Shell, and Total Energy with the purpose of facilitating the decarbonization of the industrial sector. At the facility in Øygarden on the west coast of Norway, CO2 will be stored and pumped into subsea wells. The pressurized CO2 will be managed in pipelines and tanks, requiring the installation of PSVs to ensure safety.
The facility has 65 PSVs in total, distributed over three levels. The highest PSVs are placed on top of the tanks 35m above ground level.
During the commissioning, the PSVs must be tested and recertified to ensure they are functioning according to specification. They are also included in the maintenance system and will be used as a baseline for evaluating future test intervals.
Campaign Scope:
- 65 PSV's
- 24 @ 21.8 Bar
- 2 @ 33.0 Bar
- 23 @ 48.0 Bar
- 16 @ 180 Bar
- Planned 10 days (7.5 h) of testing
- 2 PSV technicians
- 1 Inline X in situ test unit
TRADITIONAL VS INLINE X
When investigating the options for the first round of PSV testing, two main alternatives were evaluated: Traditional workshop testing and an Inline X in situ test.
All handling and transportation of the PSV risk affecting its function, as even minor hits can affect the internal components.
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TRADITIONAL IMPLEMENTATION
The traditional approach would include the following operations:
- Renting and using a mobile crane.
- Dismounting, lifting, and re-locating PSVs to a position suitable for the crane to lift.
- Loading of PSV baskets on a truck.
- Transporting PSVs in batches to the workshop.
- Lifting in and out of testbench.
- Manual testing and reporting of test results.
- Lifting and transportation back to the facility.
- Using the crane to lift PSV into place.
- Re-mounting the PSV.
Performance
Another drawback is that traditional testing does not ensure the PSV fully functions when re-mounted at the facility. The PSV's performance could have been affected during transport, lifting, or mounting back into service.
Documentation
The reports from a traditional test bench are based on manual gauge readings and rarely include digital recordings of the test process and operations performed.
IMPLEMENTATION WITH INLINE X
Testing PSVs in situ with the Inline X test unit does not require lifting or cranes. It is the equivalent of bringing the workshop to the PSV instead of the other way around. Reporting is an integrated part of the testing process, and certificates are provided in PDF format when the test is completed. All test data is available and provides full traceability of the test operations. The performance and characteristics from the test data of the PSV can be used as a comparison when performing the next functional test. The following steps were required to perform Inline X in situ testing:
- Add valves, tags, and test parameters to the Inline X cloud for online access during testing.
- Rent and use of instrument air compressor and n2 bottle manifold.
- Mobilization of the test unit. Connection of hoses from the test unit to the PSVs.
- Run the automated function test.
- Disconnection of hoses.
- Demobilization of equipment.
Risk
A traditional approach involves flange splitting, crane lifts, and sometimes heavy lifting above pressurized systems, all of which are considered undesirable risk elements with possible human, material, and environmental consequences.
OUTCOMES
The commissioning of the PSVs at Northern Lights, using digital in situ testing, proved to be even more effective than anticipated. The testing was completed ahead of schedule, with no need to dismantle any PSVs.
55% Time Reduction Less than the estimated ten days (9) were required to complete the scope of the 65 PSVs. It was estimated that traditional workshop testing would have required 20 days.
50% Cost Reduction Cutting transportation and rental costs for mobile cranes and fewer hours spent in the field by the PSV technician lead to significant cost reductions.
HSE reduction During the campaign, no crane lifts or flange splitting were performed.
Increased PSV reliabillity Compared to the traditional approach, the in situ tested PSVs are proven to function as intended while mounted in service.
FUTURE WORK
The overall execution, from planning through testing and reporting, was considered a success. Inline X in situ testing will be the preferred function test method when re-testing the PSVs next year.
