|
Nikiski GTL plant tests new, economical design BP Exploration to start $86 million GTL plant, testing smaller design and implementing water, hydrogen recycle systems Patricia Jones PNA Contributing Writer
With a scheduled startup this month, the new gas-to-liquids plant being built in Nikiski by BP Exploration (Alaska) Inc. will test plant design characteristics as well as evolving technology in a combined effort to increase efficiency — and lower costs — of the chemical conversion process.
During an energy workshop held in early April in Fairbanks, Steve Fortune, BP Exploration’s GTL program manager, provided an overview of the three-stage chemical process in which natural gas is converted to a usable liquid, such as diesel, jet fuel or naphtha. He also described in detail the company’s latest efforts to utilize that conversion process, by building a $86 million GTL plant in Nikiski.
BP Exploration expects the plant to convert 3 million cubic feet of natural gas per day into 300 barrels of liquids, Fortune said.
“We’ve got some clever engineering to try to make this reaction much more efficient,” he said. “Theoretically, it’s only 78 percent thermally efficient, so there are some challenges in there, trying to make this a commercial application and a process that will really work, and to try to recover some of our energy back.”
Some of the unique design characteristics of the GTL plant in Nikiski, such as water recycling, use of hydrogen as a fuel source and a small, modular-type of construction, are attributes which would greatly enhance the economics of building and operating a similar facility on the North Slope.
“What we’re building in Nikiski is off-the-shelf design reactor and an off-the-shelf catalyst, so there’s no real development there,” Fortune said. “What we’re looking at is the operating envelope.”
Conventional technology in new, smaller design During his presentation, Fortune displayed a slide showing a scaled drawing of a conventional world class GTL plant, one already built and operating in Trinidad, he said. Contained inside the conventional plant drawing was the much smaller GTL plant that BP is building in Nikiski.
“Using our compact reformer technology, it’s one quarter of the size of conventional technology,” Fortune said. “That’s the real breakthrough. It’s not really the chemistry or the reactions.”
Reducing the size of the reformer, where the first stage of the gas-to-liquids conversion takes place, enhances the overall economics of the process, he said. And those cost savings are particularly applicable to construction and operation of such a plant on the North Slope.
“If you’ve got equipment that’s one-quarter the size of conventional technology, not only is your equipment cheaper, but the modules are now much smaller,” Fortune said. “You can see how the effect of making everything smaller can compound and produce quite a significant savings for a project on the North Slope.” Recycling water, hydrogen for improved efficiencies During the second stage of the gas-to-liquids conversion process, water is produced as a by-product. BP’s plant in Nikiski will recycle 97 percent of that water, Fortune said, a great operational benefit if such an operation were located on the arid North Slope.
“That helps reduce the actual amount of freshwater needed,” Fortune said. “That helps for somewhere like the slope, which is an Arctic desert, where water is not in abundance. That’s another unique characteristic to our reformer.”
During the initial stage, where natural gas is liquefied, hydrogen is also produced in the chemical process. Unique to the BP Exploration plant in Nikiski is a method of separating that hydrogen and recycling it as a fuel source for the compact reformer.
“The hydrogen separated out provides 80 percent of the energy input needed for that syngas reaction,” Fortune said. “In doing that, we’re actually minimizing our carbon losses. Now we’re not just burning natural gas to provide that heat.”
In addition, by burning the hydrogen instead of more fossil fuels, CO2 emissions from the conversion plant are greatly reduced, he added. “That’s quite a unique feature in the flow sheet of the plant down in Nikiski.” Plan of operations for GTL plant Construction of the GTL plant in Nikiski started in February 2001. During his presentation in early April, Fortune said the plant was 96 percent complete. He anticipated startup sometime in May.
Currently, BP Exploration plans to operate the $86 million GTL plant in Nikiski for about five years, although it should take up to 18 months to test out the design and technology, Fortune said.
“We say five years because we already have things coming along in the laboratory that will help reduce the cost even further for GTL,” he said.
Owning and operating a plant in Nikiski can “accelerate bringing the technology from lab to commercial use,” he added.
Installing the “latest, greatest” technology for control, transmitter and communication devices will aid in that effort. Data from the plant will be sent immediately via Internet to team members of the BP-led GTL research effort all over the world.
“We’ll be able to communicate information in real time — not waiting for data to get to London and back,” Fortune said. “That will be really beneficial to proving the technology.” Why is BP interested in GTL? Besides the obvious — a huge resource of natural gas on the North Slope deemed uneconomic to develop using conventional, pipeline transportation systems, BP Exploration sees a future demand for GTL products.
“The transportation fuels produced by GTL are very environmentally friendly,” Fortune said. “They’re very clean fuels, with no sulfur, very low nitrogen compounds and no aromatics. From an environmental aspect, the (GTL) fuels are very superior, high quality fuels produced.”
In addition, development of the clean fuel source could open the door to other emerging technologies, he said. “Not just transportation fuels, but other chemical feedstocks and power fuels in the GTL process.”
For example, the hydrogen produced in the chemical process could be used for other fuel sources. Right now, costs are prohibitive to produce hydrogen as a standalone product, but the GTL process “could be a bridge to the hydrogen economy.”
As part of operations at the Nikiski plant, a separate research project will be conducted. Under a U.S. Department of Energy grant, a natural gas fuel cell will be installed to produce 250 kilowatts of electric power. Some of the electricity will be used at the GTL plant, both for its administration building and for plant lighting, and the remaining amount, about 100 kilowatts, will be sent out on the existing power grid.
Fortune said the natural gas fuel cell is a $6.5 million demonstration project, with partial funding from DOE. BP Exploration is partnering with Siemens in the project.
| 