|
GTL experiment may hold key; tests could pioneer North Slope plant Overall conversion of energy in Nikiski plant’s process could be as high as 75 percent; a major improvement over the 60 to 66 percent conversion rate achieved in past, says BP’s Steve Fortune Allen Baker PNA Contributing Writer
A pilot plant in Nikiski to convert natural gas to liquid fuel could provide a major step toward making the long-sought technology commercial. If the predictions of BP’s scientists pan out, BP could spend billions of dollars on a big North Slope plant that would produce 30,000 to 100,000 barrels of synthetic crude, or more, every day.
The overall conversion of energy in BP’s process could be as high as 75 percent, said Steve Fortune, engineering manager for the facility. That would be a major improvement over the 60 to 66 percent conversion rate that engineers have used as a rule of thumb in the past.
The $86 million testing facility in Nikiski, expected to produce 300 barrels a day, is 93 percent complete and should be working sometime in April, Fortune told the PacCom conference Feb. 20.
“One of the key things we have to do is prove the technology works,” he told PNA in an interview. “Then we’ll do some optimization work.” Design breakthrough? Much of the improvement in efficiency comes from a compact reformer that BP has designed for the first stage of the three-stage conversion process, Fortune said. The reformer, which converts methane to carbon monoxide and hydrogen, is one-fortieth the size of a conventional unit, he said.
“With the much more compact design, you can be more thermally efficient,” as well as cutting production and transportation costs, Fortune said. The reformer represents about 60 percent of the overall cost of a GTL plant. Recycled heat BP’s process also recycles heat and water generated in the various steps.
“Where you’re going to get efficiency gains is how you integrate different parts of the plant,” he said. “At the end of the day, there’s nothing magical about it.”
After the natural gas is converted to carbon monoxide and hydrogen in the reformer, it’s run through a process that makes long-chain paraffins from the “syngas.” Those paraffins are then cracked in a conventional refinery process to make liquid fuels.
Diverting streams from various stages of the process could allow production of methanol, olefins, polyethylene and ethers as well.
If waste heat is used to generate electricity or steam for other purposes, the thermal efficiency of the process — how much of the energy is left in the final product — could go a bit higher, he said, but it’ll be tough to reach the 88 percent thermal efficiency of the liquefaction process. GTL versus gas line For North Slope purposes, though, GTL has a competitive edge over other methods of moving natural gas to market because there’s already a system in place that can transport liquids though the pipeline and tankers.
The production from a GTL plant could move down the pipeline, probably in separate batches since it would likely command a significant premium.
The product is free of sulfur and some other impurities, giving it an advantage over regular crude. Design is ready BP has already done much of the design work for a commercial-size facility, Fortune said, and could be ready to go to work on one in as little as two years.
The 30,000-daily-barrel size “is probably the smallest we’d want to build,” he said. “We believe we’d have no problem scaling up to that size,” which is similar to the capacity of a project being built in Nigeria by Sasol, the South African company that was a pioneer in the process, and ChevronTexaco.
“We’ve done a number of engineering studies for a 30,000 barrel-per-day plant,” he said. “They give us a very good idea of what tests we need to do” at the Nikiski plant, expected to run for five years or so.
At Nikiski, BP can “plug in” different components to see how they operate at that scale. The facility is adjacent to three other Nikiski plants, but mostly shielded from view by a curtain of trees.
Part of the design challenge for a commercial operation involves looking at transportation issues, he said, since the modules would have to be shipped to the North Slope and assembled there.
The same transport issue would likely confront other uses of the technology, which at this point is only competitive for “stranded” natural gas that can’t easily be transported to market.
BP’s plant could be expanded by building several 30,000-barrel “trains,” but there would be little additional economy of scale other than common support facilities, Fortune said.
The Nikiski plant will be used to test some new catalysts that BP has developed, particularly for the reformer stage, Fortune said. Making those catalysts in commercial quantities can be different from cooking small batches in the lab, he said.
Bringing down the cost of the facility has been the big challenge for the GTL technology, which has never really been commercially successful.
It was developed originally in Germany in the 1920s and was used to provide fuel for Hitler’s army.
The process was taken off the shelf again in the 1950s when South Africa built a plant to produce fuels after that country faced a world boycott over its racial policies.
Shell has had a facility operating in Malaysia since 1993, now producing specialty chemicals and waxes.
The industry standard for GTL facilities is about $25,000 per daily barrel, Fortune said, and that’s too high to be workable. With BP’s compact reformer, the company expects to get down to around $20,000 per daily barrel.
That’s not far from the $17,000 per daily barrel that would make the process competitive with some other uses of natural gas, such as LNG, he said. At $11,000 or $12,000, the process could compete with a new-build crude refinery, producing fuels and chemical feedstocks.
A study by the federal Department of Energy in the mid-1990s indicated that crude prices of about $30 a barrel would be needed to make a North Slope GTL plant commercially feasible with the technology available at that time.
With capital costs of about $20,000 per daily barrel, that component alone would amount to roughly $5 per barrel, about the same as the $4 to $5 a barrel in estimated operating costs. That leaves little room for paying for the gas, which can run up to $10 per barrel, or for transportation. The Sasol-ChevronTexaco plant in Nigeria will use gas that otherwise would simply be flared.
But the industry has been experimenting with the technology in recent years, trying various catalysts and altering other components to cut the overall costs.
ExxonMobil has proposed a 100,000-barrel-a-day plant in Qatar, and Sasol a 30,000-barrel project.
Shell and new player Syntroleum, in Tulsa, have also done substantial research.
BP has been involved in GTL technology since the early to mid-80s and has spent about $300 million on it, Fortune said.
BP even inherited a pilot plant at an ARCO refinery in Washington state when that company was acquired, but the project used licensed Syntroleum technology and BP didn’t get access to that, Fortune said.
BP’s work was concentrated at laboratories near London.
| 