Gas Cooler U-Tube Restored Offshore

Immediate mobilisation saves offshore platform £1000’s

The ‘hairpin’ tube Gas Cooler on a North Sea oil platform was blocked by a breakdown of ferrules (material inserts within the tube ends) in the first pass of the heat exchanger. The contract was time critical as the platform was losing 8000 barrels a day.

The Challenge

Blocked 14.83mm I.D. hairpin tubes within a shell and tube exchanger, with high pressure gas on the tube side and sea water on the shell, located on a North Sea offshore platform.
Modifications to the tube bundle included additional ferrules to the inlet quadrant to help reduce tube end erosion and erosion around the tube expansions.
Increased back pressure on the tube side, believed to be caused by a breakdown of the ferrules had blocked tubes.
Degraded insert particles were being caught in 5-micron filters downstream.
Platform production capacity was severely affected by these blockages.

The Solution

Once the header was removed Tube Tech inspected the tubes, confirming 937mm long ferrules had clogged the tube bores.
Broken ferrule sections had lodged in the ‘U’ bends of the heat exchanger, while others had folded back on themselves but remained adhered.
Bottom half tubes were severely affected with 94 tubes completely blocked, effectively limiting the unit to 5% flow.
Tube Tech used its SafeFlex system to safely drill the straight and then the tubes were then DarTTed around all hairpin bends to remove any remaining debris.

Tube Tech Comment

Scott Donson, Technical Director: “We originally thought the project would take 48 hours and were pleased that it was completed in less than 24 hours. Tube Tech’s ability to mobilise so quickly was a huge bonus to the client.”

Is your facility suffering from reduced output? Contact our team today for a free technical evaluation to begin your journey to heat transfer recovery.