EA2 On-Site Power Turbine Overhaul | Case Studies | Greenray

A field engineer was required at a power station in Northern Ireland at very short notice to inspect a power turbine (PT) following an Avon failure. The PT was found to be heavily damaged requiring a strip down of the gas path to ascertain the full extent.

The engineer was joined by another Greenray engineer and remained at site for a further 7 weeks to strip the unit. The damage was assessed and spares ordered. The engineers returned to site, completing a rebuild and successful balance and commissioning of the machine within 5 weeks.

The Engine

What we worked on

EA2 power turbine, powered by two Rolls-Royce Avon gas generators

The Challenge

Unplanned work on equipment which is rarely dismantled

Due to infrequent major overhauls of this type equipment, the client's knowledge of this equipment had been lost over time. This was particularly key in this case as there was a significant level of dismantle required following failure.

This was combined with the fact that specialist tooling had gone missing from the site. Greenray solved this problem by using its extensive network of industry contacts.

The power turbine had never been stripped since installation, and due to this being a coastal site, the equipment was heavily corroded.

In addition, stationary, rotating blades and rotor disks were heavily corroded.

The Solution

Using our relationships with our client's and close support from Greenray engineers

  • Greenray ensured that the necessary special tooling was in place, using its extensive network of industry contacts.
  • Due to the issues with general corrosion, Greenray also manufactured special tooling using the client's workshop to aid in the stripping of the power turbine.
  • Where parts were required, Greenray shipped them from its extensive stock on a breakdown basis.
  • Greenray and the client's site management team put together a safe working plan with risk assessment and method statements that allowed the overhaul work to commence without impacting the sites other operational equipment.
  • The work was hampered by the presence of asbestos, and Greenray closely assisted the client's removal team.
  • Stator blading was removed and sent to Greenray's overhaul facilities, where all but one was repaired using advanced techniques developed for this purpose. As well as minimising the cost impact, this also shortened the overall length of outage substantially.
  • The rotor disks were cleaned and non destructive testing was carried out by Greenray. Concessions where made meaning approval was given for commercial operation, again leading to a substantial reduction in overall outage time and cost. Particularly as rotor discs of this type can have a substantial lead time.
  • Using computer modelling developed by Greenray, the blades were located around the disks, resulting in reduced vibration levels once the machine was commissioned. This reduced the site work by a number of days.
  • Blade tip clearances were resolved on-site, again using Greenray special tooling and established engineering techniques.
  • Greenray's on-site team were retained through the entire outage to ensure continuity and to ensure pre-emption of possible issues.

The above activities, resulted in the shortest possible timescale, for the machine return to commercial operations.

About Greenray

Bringing you expertise right from the heart of the industry

As a significant player in the water and energy industries, we have an active role in the service, maintenance and overhaul of turbo machinery. Our services include plant relocation and installation, control system retrofits and rehabilitation projects, workshop services and on-site overhauls, component repair and supplying spare parts and technical services.

Why work with us ?

Choosing Greenray

At Greenray, we strive to continually develop our capabilities in order to provide an unrivalled service. We perform our service capabilities in conjunction with OEM partners to provide the most comprehensive service to our customers.

International services

We work anywhere in the world, and our field engineer's travel all over the globe to carry out our services.

Insider knowledge

We are specialists in legacy equipment services. Working with OEM Partners, we secure access to the original equipment manufacturing drawings, allowing us to reengineer in the most sympathetic, effective way, using the right materials and with the knowledge of the machine history.

We work to understand the history of your machine, from its initial design right through to each new component and specification. This helps us to source the correct parts and adapt them accordingly.

Unrivalled expertise

Our people are experts and they're all our own. We're extremely proud of our field engineer's pedigree, with expertise ranging from working in difficult offshore environments through to land power generation.

A proud history

Legacy machines are in our blood and everything we do is designed to work in the best possible way with them.

Preventing problems

Although we're adept at solving problems, we prefer to prevent them through regular servicing, which highlights issues before they become a problem.

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A new lease of life

A field engineer was required at a power station in Northern Ireland at very short notice to inspect a power turbine (PT) following an Avon failure. The PT was found to be heavily damaged requiring a strip down of the gas path to ascertain the full extent.

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