Preheating of turbine
The EFD Induction technician were rushed to the platform to heat and remove the turbine’s thrust collar, auxiliary gear and coupling hub from the turbine rotor.
Induction makes waves offshore
BP, Rolls-Royce, KCA DEUTAG — each a major international company with rigorous standards on worker safety, economic efficiency and environmental protection. And each a company that uses EFD Induction expertise in the demanding conditions of North Sea oil and gas fields.
Imagine the dilemma. You are about to carry out maintenance work on a Rolls-Royce gas generator located on a BP North Sea platform. Normally you’d use a gas torch/naked flame to heat and remove the various components — thrust collar, auxiliary gear, coupling hub — attached to the generator’s power turbine shaft. But there’s a problem. Since the generator is located in a designated hazard zone, the use of open flame means the platform’s production wells must be shut-in, and all hydrocarbon production must cease.
But for Adair Swan and his colleagues at Rolls-Royce, the dilemma was anything but imaginary. It was real.
Naturally, BP were anxious to find an alternative to gas open flames for turbine maintenance. It wasn’t long before their attention was drawn to EFD Induction. Paul Evans of EFD Induction UK recalls what happened next: “Well, this is North Sea oil and gas production; an industry that along with nuclear power is perhaps the most rigorously regulated and safety conscious in the entire UK. So our first task was to organise a workshop trial of our induction heating solution. Rolls-Royce and BP weren’t just going to fly our equipment out to a platform. To be even considered a viable option, we had to first satisfy these companies’ strict operational and safety requirements. But the trial went well, and Rolls-Royce and BP decided to go ahead with a further test — this time offshore.”
The offshore site chosen for the second trial was a redundant package of the Bruce Platform. Located 380 km northeast of Aberdeen on the east coast of Scotland, the Bruce Field is one of the largest gas/condensate (light oil) fields in production in the UK North Sea. Plans for the on-site were moving ahead when fate dramatically intervened. Jon Philpott, EFD Induction UK Offshore Application Manager explains: “Just before the planned offshore trial there was an unscheduled shutdown of a power turbine rotor on the Bruce Platform. Our equipment and an EFD Induction technician were rushed to the platform to heat and remove the turbine’s thrust collar, auxiliary gear and coupling hub from the turbine rotor. Once a new rotor was installed, induction heating was used to reassemble the components.”
The new standard
The emergency intervention by EFD Induction on the Bruce Platform was a great success from an operational and safety perspective. Indeed, according to Rolls-Royce, the use of EFD Induction’s repair capabilities “resulted in the work being completed early and production restored several days ahead of schedule.”
But the story doesn’t end there. Due to the proven success of the Bruce Platform project, induction heating has been adopted as the preferred method of removing/reassembling thrust collars, auxiliary gears and coupling hubs on almost all Rolls-Royce power turbines in operation in the North Sea. Other platform operators, too, are gradually phasing out costly and dangerous open flame methods in favour of induction heating.
For EFD Induction UK, the successful Bruce Platform project was a major breakthrough. Adds Evans: “Of course, it was great to help such well-known companies as BP and Rolls-Royce. It was a vindication of everything we’ve been saying about induction — its speed, mobility, controllability and safety. But it was also great to be nominated for a BP Helios Partnership Award.” The award referred to by Evans is a prestigious recognition by BP of external partners “delivering over and beyond what is expected contractually, demonstrating true team spirit.”
Coils to the rescue
Another North Sea success story involves KCA DEUTAG, a major onshore and offshore drilling and engineering contractor. The task was similar to the BP/Rolls-Royce challenge: to heat-treat equipment on a platform rig where the presence of gas pipes ruled out the use of naked flames. However, this time the equipment to be heat-treated consisted of three mud pumps located on the Magnus Platform.
KCA DEUTAG began by removing the pumps’ covers and chains in order to start removing the drive sprockets. The first two came away easily, but then… stuck! The remaining sprocket wouldn’t budge.
A heavy-duty strongback and pulling rods were made and sent to the platform. But even with a 200 ton pull there was still no progress! The on-site technicians then considered using a conventional heated element blanket. But that would have taken too long, and raised the temperature of the shaft and sprocket. It was time to call in EFD Induction.
After assessing the situation, EFD Induction designed and made customized coils for the inside and outside of the sprocket. The coils were put in place, the heat was turned on, the puller set at a lower torque, and presto! The sprocket came off without any problems. Two other customized EFD Induction coils were then used to remove and replace all the bearings. And the operation was completed safely and in record time. KCA DEUTAG have since used induction heating — and the specially made EFD Induction coils — for similar jobs on other North Sea platforms.