SST400 Steam Turbine Maintenance Works in the South of England

Oct 16, 2019

At Greenray we pride ourselves on our ability to be flexible and agile in our approach to both the workload and our customer requirements. This has always been paramount to Greenray’s philosophy of putting the customer first!

This was recently demonstrated when Greenray were contacted by a major steam turbine OEM with a request to provide skilled labour for major maintenance works on an SST400 25 MW steam turbine. The turbine is based in the South of England and operates in the Green Sector Biomass industry, burning wood pellets as its fuel source to produce steam for power generation.

Despite heavy workloads at other locations, Greenray were able to provide and mobilise 3 members of our field service team within 5 days. Due to our rapid response, Greenray were able to achieve the very tight deadlines imposed by the delivery of spare parts to site. The team can be seen carrying out diaphragm alignment checks and refitting the rotor assembly.

To meet high operational demand, the site owner required the unit to be back on‐line at the earliest opportunity. After review, the team split into an early/late shift pattern. This gave the greatest efficiency of resources onsite and ensured that the turbine build process completion was ahead of schedule at time of demobilisation.


Tasks performed by the Greenray field service team included:

• Preparing casings, components and the refurbishment of bolts, dowels and studs.

• Installing lower blade carriers.

• Installation of dummy rotor and bearings.

• Installation of measurement instrumentation.

• Install upper blade carriers.

• Detailed measurement of fittings.

• Removal of measurement equipment, dummy rotor and bearings.

• Adjustment of lower blade carriers

• Fitment of main bearings and rotor.

• Replacement of inlet rocker bearing.

• Re-install upper blade carriers.

• Modification to main casing drain system.

• Alignment of rotor and verification checks.

• Clearance checks.

• Installation of top half casing and main pipework.


Greenray were not present at the time of recommissioning, however, feedback received from the OEM was very gratifying:

“Your guys were very good, very professional and we would have happily kept them on this job until the end, hopefully we will be able to work together in the future.”