WHRU / Hot Oil Heater Unblocked and Descaled Without Cutting

Solidly blocked tubes only accessible through header box


The WHRU / hot oil heater had become restricted with a thick, hard carbonised deposit. For the contractor, Demag Delaval Industrial Turbomachinery, Siemens gas turbine business in Aberdeen, there were also wider issues attached to the problem and the company needed a detailed evaluation of the WHRU’s future lifespan. For a new one to be manufactured would require six months and a cost running into hundreds of thousands. Other ramifications would also be a possible loss of production on the rig while a new unit was built.


  • WHRU/Hot Oil Heater restricted with thick, hard carbonised deposit.
  • Clilent needs to access future lifespan of the WHRU.
  • Replacement of the WHRU was being considered, at a cost of approx £150 000
WHRU arrives at Tube Tech head office WHRU ready for cleaning WHRU ready collection after cleaning Morning cleaning information


  • Tube Tech has particular experience in unblocking, descaling and cleaning the difficult bends that are peculiar to WHRUs in the oil and gas industry.
  • Tube Tech teams have successfully cleaned a number of them in the past at competitive cost.
  • The answer in this case was for the WHRU/hot oil heater, which was already on land having being removed from an offshore oil rig, to be transported to Tube Tech’s headquarters.
  • The 14.5-tonne WHRU arrived within 48 hours and teams armed with specialist equipment and knowledge set about a three-stage operation.
  • Phase one was locating the position and length of blockages within the pipework using innovative methods developed by Tube Tech. Phase two was systematic unblocking and finally a thorough clean. Tube Tech’s method did not involve cutting nor removal of any U-bends. Part of the cleaning procedure was to manipulate the position of the WHRU by using two cranes to turn it at the various angles needed to work on it. It was one of the biggest the Tube Tech teams had handled.
  • The WHRU/hot oil heater was descaled and unblocked in just two weeks and because it was at Tube Tech’s headquarters the evaluation of its possible lifespan could be carried out in detail.
  • DDIT took delivery of the cleaned unit after as little disruption as possible and were pleased with the verdict that it would not need to be immediately replaced having saved £150,000 in possible manufacturing costs and subsequent rig production losses.

Client Comment

DDIT’s Customer Support Manager: “We were exceptionally pleased with Tube Tech’s work and the cleaning performed has saved a significant amount of capital. The unit had been removed from its operational site and the easiest way to proceed was for it to be transported to Tube Tech’s premises.”

Tube Tech Comment

Martin Byford, Operations Director: “The WHRU project was another unique project requiring all the technical skills and team work on which our reputation is based. The tubes being so solidly blocked, having so many bends and only accessible through the header box, presented the biggest challenges. The pipework was still descaled and cleaned in just two weeks heralding another first. Our team did an excellent and cost-effective job.”

For more information or to discuss your cleaning challenge call us on +44 1268 786999 or e-mail info@tubetech.com, alternatively click here to fill out our contact form.