N E W S   R E L E A S E   from  FURMANITE  AUSTRALIA

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Improving turbine efficiency

Unique engineering and machining capabilities from Furmanite, the speciality services company geared to maximising asset uptime, have helped modify and upgrade a number of turbines at an Australian power station, enabling an increase in output to be achieved without the expense of replacing the turbines, and the outage time to be kept to a minimum.

Improved efficiency was required to increase power output from the 200MW-designed Parson turbines to 210MW – but with no increase in steam supply as this was not available. To help avoid the multi-million dollar cost of turbine replacement (and the long lead times involved even if this were a viable alternative), a proposal was put forward by the original equipment manufacturer to upgrade the existing turbine, involving modification of the row 1, 2, 5 and 6 blades.

The necessary work included modifications to the existing turbine casings, involving some complex machining requirements, which had to be done within the shortest possible time, so Furmanite was called in to help with its high level expertise.

“Several modifications were required, and had to be done with the casing together and with the minimum number of cover lifts. But the most challenging was the need to machine new steam corridors into the casings to accommodate the new blade tip design for the row 5 and row 6 blades – about 2.5 and 3.1 metres in diameter respectively,” Furmanite Australia’s Mark Taylor explained.

“The new profiles required the casing to be bored and then faced at an angle, with a radius at the intersection between the two. The tolerances on the final diameters were demanding too – at +0.15mm. It would have been a difficult job with standard line boring equipment, but we’d developed a special 5 metre long 8 inch boring bar with a coping attachment and facing head that followed the required profile. This meant not only that we were able to achieve what was required, but that we could do so quickly and cost-effectively,” he added.

Time was of the essence in this project to bring the plant back on-line and produce the necessary power output, and Furmanite applied its engineering expertise to save a further 24 hours in the outage programme, by manufacturing a second machining arm attachment. This enabled both ends of the casing to be machined without having to remove the upper casing to relocate the machining arm to the other side. Laser alignment equipment was used to align the bar within the casings.

“By designing the machining arms to be modular, all the machining tasks required inside the casings could be performed without having to remove the upper casing to adjust the equipment,” Taylor pointed out.

Other modification work carried out by Furmanite included machining slots to accommodate a new design of sealing strips into the half joint faces of the LP casings. Forty slots, of 32mm width by 10mm depth and approximately 300mm long, were machined to a tolerance of 0.5mm, using a one metre linear rail off-set milling slide. The seals on the new row 1 and 2 blades (about 1.5 metres) were also tipped to size.

Furmanite’s ability to develop its machinery to meet the specific requirements of the job made a key contribution to enabling the turbine upgrade to be completed on schedule.

For further press information contact:
Sarah Manwaring-White
Keep in Touch Ltd
Tel: +44 (0)1451 844 488
Email: sarah_mw@keepintouch.co.uk