Offshore/Upstream – Aligning a 1 MW
On board a compression platform in the Dutch North Sea, the crew noticed increased vibrations in a generator. An advanced diagnostic engineer from AVT Reliability BV (formerly Van Geffen Reliability) was flown in to diagnose the problem.
| Customer | Upstream (Exploration & Production) |
| Location | Offshore – The Netherlands |
| Industry | Oil & Gas |
| Process | Power Generation |
| Equipment | (Gas) Generator |
| Products | Alignment equipment |
| Services | Advanced Diagnostics |
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The Challenge
Due to missing historical measurement data and the abnormal vibration level, it was deemed unsafe to continue operating the installation for an extended vibration investigation. Thus, initial conclusions were drawn solely based on steady-state measurements.
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Our Findings
An increased first-order vibration component was identified as the cause of the elevated vibration level. Given this finding and the recent maintenance on the unit, we initially conducted a visual inspection and alignment check. The “hot alignment” check revealed abnormal alignment values, which were significantly excessive even for a flexible coupling.
Our Approach
As both alignment and coupling specifications were unavailable on board, we initially performed an alignment calculation. Based on these calculations, a pre-setting was determined to compensate for thermal growth and dynamic settlement, followed by realignment of the installation. We also carefully considered factors such as soft foot, the shim plan (particularly the number of shims per foot), and other relevant details.
The Solution
Verification measurements following the alignment correction revealed a significant reduction in vibration levels. A subsequent hot-alignment check confirmed accurate “axis-left” alignment. Optimizing the alignment conditions successfully reduced vibration levels and forces within the system, enabling the unit to operate at optimal performance.
Follow up
To ensure the availability and reliability of this and other critical production units on board, they are included in an annual health check program.
