New compressors boost WA energy

A recent upgrade to the Dampier to Bunbury Natural Gas Pipeline (DBNGP) in Western Australia provides increased gas flow to local energy providers and features several turnkey air compressor packages.

Extending almost 1600 km from Western Australia's North-West Shelf gas fields down to the state's south-west, the DBNGP is one of the longest and largest capacity natural gas pipelines in Australia. Built by the State Energy Commission of Western Australia (SECWA), the pipeline supplies natural gas to industrial, commercial and residential customers in Perth and major regional centres along the pipeline route.

The DBNGP is owned by Dampier Bunbury Pipeline (DBP), which in turn is made up of a consortium of companies, including leading Australian energy infrastructure provider Alinta. With a capacity of 637 TJ/day, the DBNGP represents a crucial link in Western Australia's energy distribution network.

To meet Western Australia's growing energy demands - particularly in the state's south-west - DBP recently embarked on a multi-stage expansion project to upgrade the DBNGP. Currently in its fourth stage of development, the DBNGP expansion includes the installation of eight gas 'booster' stations, increasing the pipeline's delivery capacity by over 100 TJ/day. The project scope also incorporates over 200 km of new pipe looping.

The major upgrade and expansion project represents a significant engineering achievement and incorporates contributions from some of Australia's leading industrial and engineering companies. Alinta Asset Management managed the project and enlisted the services of one of Australia's leading providers of professional services to the energy, resource and complex process industries, WorleyParsons.

Located along the length of the pipeline in some of Australia's most rugged and remote locations, the booster stations are subjected to a range of demanding environmental conditions. Designed and manufactured to advanced process and electrical specifications, the booster stations feature sophisticated control functionality.

According to Alinta senior project manager Michael Dunn, the reliable operation of the booster stations is essential in remote, unmanned installations such as these. "You can't afford to have breakdowns out here," says Dunn. "Most of the booster stations are located in isolated areas where it can take a full day to reach them from any regional centre. Reliability is paramount."

Notorious for its temperature extremes, Australia's interior is one of the most demanding environments for any industrial application. "In the summer months, temperatures regularly soar beyond 500C," says Dunn. "It was crucial that all of the engineering packages associated with the booster stations were designed and manufactured to withstand the hot, humid and dusty conditions often experienced in Australia's outback."

Providing all engineering, procurement and construction management (EPCM)-related services, WorleyParsons drew on a number of engineering specialists to complement the oil and gas giant's engineering expertise. Australian industrial air compressor designer and manufacturer, Champion Compressors provided each booster station with a fully engineered and tailored compressed air solution. Providing instrument air for the actuation of the booster station's numerous control and shutdown valves, and general pneumatic devices, the Champion compressed air packages are vital to the operation of the DBNGP.

Designed, manufactured and commissioned by Champion, each skid-mounted turnkey compressed air package includes two 30 kW Champion CSF30 air compressors - one 'operation' unit plus one 'standby' - as well as a desiccant dryer and air receiver. The compressors are fitted with an automatic lead/lag controller, enabling the selection of one 'operating' and one 'standby' compressor. "This designation can be alternated to ensure equal load sharing across the two compressors," says Champion Compressors sales engineer, Quentin St.Baker. "In the event that the plant's compressed air demand exceeds the output of the operational compressor, a pressure sensor on the compressed air output ensures the standby compressor kicks in and makes up the difference. An alarm signal is also sent to the plant's communications system to advise the off-site controller that the standby unit has been activated."

To provide extra compressed air capacity and accommodate the region's harsh environmental conditions, the air compressors were supplied with 'stepped output control'. "All the compressors were designed with a motor/drive combination featuring a 20% de-rated drive speed - a drive speed that would ordinarily be offered with a machine that supplies compressed air at a higher pressure," says St.Baker. "This means that the compressor doesn't work as hard to produce the required compressed air output. The compressor will run cooler, producing 20% less heat than it would if fitted with a regular motor/drive combination. Additional benefits are a longer lasting motor and airend, and less wear on all compressor components."

DBP is gearing up for stage five of the expansion project. Planned for completion in mid-2008, this next stage of the DBNGP development will also involve a further upgrade and expansion of pipe looping and gas compression. It is anticipated that with the completion of stage five, the pipeline will be duplicated most of the way between Dampier and Bunbury, increasing the full haul capacity of the dual pipeline by 310 TJ/day.

The increased production of natural gas provided by the further expansion of the DBNGP is set to deliver a significant boost to Western Australia's energy sector. "With a proven track record in the oil and gas industry, Champion Compressors looks forward to contributing to the ongoing success of Western Australia's energy industry," says St.Baker.

"This is an exciting time for both Alinta and the energy and resource sector," says Dunn. "Abundant competitively priced energy will almost certainly lead to growth in the Western Australian economy and local industry. Shippers, energy providers and users in Western Australia will have access to levels of natural gas never seen before."