Clean compressed air for gas turbines at Kwinana

Synergy’s Kwinana Power Station (KPS) is located 40 km south of Perth and is connected by 66, 132 and 330 kV transmission lines to the South West Interconnected System (SWIS). SWIS is the primary electricity grid in Western Australia (WA), supplying the bulk of the southwest region - an area which stretches north to Kalbarri, south to Albany and east to Kalgoorlie. KPS is unique in WA in that it is capable of burning three fuels - coal, natural gas and oil.

In 2012, UGL was commissioned by Synergy to build two high-efficiency gas turbines (HEGTs) on the Kwinana site. These were to be installed to replace two decommissioned 120 MW steam-powered generators. Requiring compressed air to aid the operation of the new HEGTs, and having previously worked on several other projects together, UGL called on Kaeser Compressors Australia.

The production of absolutely clean compressed air was paramount to the project. As a result, UGL chose to install four Kaeser DSG-2 series dry-running rotary screw compressors. As Jeff Coyle, engineering manager at Kaeser Compressors Australia, said: “UGL had very explicit clean air requirements for the turbines which the DSG-2 series dry-running screw compressors could meet.”

Two Kaeser compressed air stations were subsequently installed next to each of the HEGTs. Each station consists of two compressors, two desiccant dryers, a 13,000 L capacity air receiver, a Sigma Air Manager and carbon filters.

Matthew Weston, site manager at Synergy’s Kwinana Power Station, said: “Their key task is to keep the turbines bearings in position … during operation and cool-down. We also use low-pressure clean air for insulation purposes during isolated phase bus operations.”

Even with Western Australia’s arid climate, these compressors are able to run smoothly at ambient temperatures of 45°C or higher. One compressor in each station is on continuous run, while the other provides full standby cover. The machines are rotated regularly to maximise the life cycle and efficiency of the station. Coyle concluded:  “The compressors (when maintained properly) will meet or exceed the life of the HEGTs. They will continue to proficiently support the HEGTs that generate such an important energy source throughout Western Australia.”