Waste Heat Recovery Unit (WHRU/Hot Oil Heater) Clean Saves £500,000

Deposits and scale extracted with novel engineering approach


A process malfunction involving the Waste Heat Recovery Unit (WHRU/hot oil heater) at a gas plant resulted in contamination with oil, which had been subjected to temperatures in excess of the usual high operational norm. Tube Tech was able to avoid cutting the serpentine coil and helped the client avoid costly replacement of the WHRU/hot oil heater.


  • The 250 metres of 2-inch diameter serpentine pipe-work within the WHRU had become coated with a thick, hard carbonised deposit.
  • The manufacturer of the WHRU’s past experiences suggested the problem could only be solved by replacing the unit.
  • The client’s initial cleaning option was removal of the WHRU/hot oil heater module, which would have meant three weeks of down time.
  • There was also substantial performance reduction and additional costs from having to find alternative ways to heat the oil for production.
  • A traditional approach would have included removing the serpentine and cutting off the U-bends which would have taken at least six operational days plus another six for re-installation.


  • We believe that this is the only time a WHRU/hot oil heater, serpentine descale has been performed in-situ. it was carried out in just three days, dealing with the WHRU’s 21 bends on each 2-inch tube – 25 ft above the ground.
  • We avoided cutting the serpentine coil. Deposits and scale were extracted using a device specifically developed by Tube Tech to overcome the difficulty of access through a 10-inch header flange at a 90 degree angle to all 2-inch serpentine tubes.

Client Comment

A Process Reliability Engineer said: “The manufacturer told us that in its experience the only way to deal with our problem was a replacement. Tube Tech avoided that with a novel engineering approach. They did a first-class job. To take the whole thing out, replace it, plus structural support costs and crane age, we were looking at perhaps £500,000.”

Tube Tech Comment

Scott Donson, Technical Sales Manager: “This contract was a perfect opportunity for us to once again challenge traditional cleaning methods and we were pleased to have helped the client avoid the expense and inconvenience of replacing the WHRU/hot oil cooler.”


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.