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Energy Frontier

Australia's remote north coast is the setting for a new cost-efficient liquefied natural gas project.

Photographs by Michael Coyne/Black Star Photos

Australia’s Northern Territory is known for its stark, beautiful Outback, its indigenous Aborigines, and the movie character Crocodile Dundee. It’s a remote place and the capital, Darwin, is the remotest of all, located at the country’s Top End on the edge of the Timor Sea.

Lately, however, the area has begun to shed its image as the nation’s last frontier—thanks in part to a major new energy plant under construction at Wickham Point, not far from the palm tree-dotted shores of Darwin Harbor. The A$1.4 billion facility, engineered and built by Bechtel, will have the capacity to produce 3.5 million tonnes of liquefied natural gas annually.

The Darwin plant is one of several current projects that have vaulted Bechtel into a leadership position in the flourishing LNG industry. The company also is working on a new 5-million-tonne-per-year processing train at the big Atlantic LNG facility in Trinidad, an Egyptian plant that will boast two 3.6-million-tonne trains, and a 3.4-million-tonne facility in Equatorial Guinea.

Like other recent Bechtel LNG projects, Darwin will use the Optimized Cascade Process licensed by ConocoPhillips and marketed worldwide by a Bechtel-ConocoPhillips collaboration. The process, now an industry standard, uses three stages involving propane, ethylene, and methane to progressively refrigerate and liquefy natural gas to a temperature of minus 161 degrees Celsius. The very first application of the process was in 1969 at an Alaskan plant built by Bechtel.

LNG takes up 600 times less volume than natural gas in its normal state, so it can be shipped economically by ocean tankers to far-off markets. LNG is stored at near-atmospheric pressure, enhancing safety. Over the past four decades, the LNG industry has recorded an outstanding safety record.

The collaboration between Bechtel and ConocoPhillips is especially strong at Darwin because Conoco-Phillips is the majority stakeholder in Darwin LNG Pty. Ltd., the owner of the project. ConocoPhillips also operates the Bayu-Undan gas field, supplying the gas to the LNG plant via a 500-kilometer undersea pipeline. All of the plant’s output will be sent to Japan under a 17-year agreement with Tokyo Electric Power and Tokyo Gas.

“By teaming with ConocoPhillips for the first time as both a customer and partner, together we’re bringing world-class resources in engineering, construction, and technology to this project,” says Bechtel Project Manager Jerry Brown.

To help meet ConocoPhillips’ goals for corporate responsibility, Bechtel engineered the project to be both efficient and easy on the environment. Innovations include the first use in an LNG plant of high-efficiency, aeroderivative GE gas turbines to drive gas compressors. The turbines—an enhanced version of the design used on Boeing 747-400 aircraft engines—are smaller and more efficient than the models traditionally used in LNG plants, so they burn less fuel.

“These turbines have never been used in LNG service,” says David Lundeen, ConocoPhillips’s project manager. “They have higher efficiency than industrial turbines, so they produce significantly fewer greenhouse gas emissions.”

 To increase efficiency even more, Bechtel designers came up with a way to capture and utilize waste heat from the turbines, which otherwise would be released into the atmosphere. What would be the most efficient application of the technology to date is further enhanced by a superefficient air-inlet humidification system for the turbines.

“The plant will discharge less carbon dioxide into the air, effectively reducing discharge of waste products to zero,” says Bechtel Site Manager Hal Thornberry. “This will be one of the greenest LNG plants anywhere.”

Although it won’t be the largest LNG facility in the world, Darwin will have the largest aboveground storage tank. At 47 meters high and almost 100 meters in diameter, it will hold up to 188,000 cubic meters of LNG. To virtually eliminate the possibility of a leak, the tank will be double-walled, with an outside wall of concrete and an inner lining of nickel alloy steel. A similar approach is used in LNG ocean tankers, which have double hulls.

The storage tank isn’t the only behemoth at the 65-hectare project site. In July 2004, a 369-tonne carbon dioxide absorber arrived after being transported on an 80-meter-long procession of prime movers and a multiaxle platform from nearby East Arm port. It was one of the longest and heaviest transport operations in the territory’s history.

In addition to the gasification facility and storage tank, the project calls for construction of a 1.3-kilometer jetty for load-out of the LNG and interface with the incoming undersea pipeline.

Bechtel brought its global resources to bear on the project. Plant design took place in Houston and New Delhi, and the project team included experts from the company’s Oil, Gas & Chemicals and Mining & Metals business units, along with employees who worked on the Millmerran Power and Comalco Alumina Refinery projects, both recently completed by Bechtel.

As in all Bechtel projects, a safe workforce is the No. 1 priority at Darwin. Through training and supervision, the company’s Environmental, Safety & Health program has been embedded in the project, and the workforce has embraced Bechtel’s Zero Accidents philosophy. As a result, by mid-2004 the project had passed 1 million work hours without a lost-time accident.

The project also made good use of Six Sigma, the data-driven approach that is helping improve quality throughout Bechtel. More than a dozen Six Sigma teams were deployed to determine risks to the project’s schedule and budget, and to find and implement ways to improve performance. As a result, the project is as efficient as the LNG plant itself.

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