Friday, January 10, 2014
Douglas Elliott is a self-described odor connoisseur. His laboratory, in particular, smells like a foul combination of rotting eggs, dirty socks and wood smoke.
Across the room, a bucket of dark green algae slurry is pumped into a chemical reactor that reaches from floor to ceiling. The complex system of tubes uses intense heat and pressure to break apart solid elements — hence the stench — transforming algae into liquid crude oil in less than an hour.
While not exactly a new idea, the process of pressure cooking certain oily algae into biofuel takes millions of years to occur naturally. What engineers at the federal Pacific Northwest National Laboratory have done is duplicate the method at a much more rapid and continuous rate, churning out several liters of algae oil per day.
That’s hardly enough to make a dent in U.S. oil consumption, which last year reached nearly 19,000 barrels per day. But companies are showing interest in using PNNL’s technology to ramp up to commercial-scale production.
With additional refining, crude oil from algae can be converted into mostly gasoline or diesel fuel. Elliott, the laboratory fellow who led team research on the project, said people should be excited about the long-term potential of fuels from alternative sources like algae.
“We won’t be pumping oil forever. We have to figure out a renewable system,” Elliott said. “That’s what this biomass is all about.”
PNNL is one of the Department of Energy’s research facilities located in Richland, Wash. A team of approximately 50 scientists spent roughly three years exploring ways to efficiently make algae fuel. Cost is still a major hurdle, as most current processes require expensive energy to first dry the material.
But the reactor built at PNNL works with a soupy algae paste that’s made up of 80-90 percent water. The system runs at 350 degrees Celsius and 3,000 pounds per square inch of pressure to split water and oil from the algae, a process called hydrothermal liquefaction.
In a sense, the process mimics what happens beneath the Earth’s surface over millions of years as algae forced underground is heated and pressurized into petroleum.
And because the system runs continuously, Elliott said it is more energy and cost-efficient than processing dried algae in batches. Leftover water and nutrients can be recycled to grow more algae.
“It’s not a perfectly efficient process, but we get a much higher yield of both liquid and gas fuels,” Elliott said. “We aren’t adding any special chemicals. It’s just heating it up under pressure.”
Growing enough algae is another challenge entirely, Elliott said. Algae grows easily, but gathering enough feedstock to meet fuel requirements is difficult, he said.
The good news, Elliott said, is algae can be grown just about anywhere.
“This is the problem we have with biomass,” he said. “Getting enough to have any impact, especially when we’re just starting out, is very difficult.”
PNNL recently published its findings, and a Utah-based company has licensed the technology to build a pilot plant. Genifuel Corp. has also worked with the lab to develop a process turning algae into natural gas, known as catalytic hydrothermal gasification.
“This really has been a fruitful collaboration,” said Genifuel president Jim Oyler in a recent announcement. “It’s a formidable challenge to make biofuel that’s cost-competitive with established petroleum-based fuels. This is a huge step in the right direction.”
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