Future Fuels

We may not think of it as much when gas is cheap, but there are many economic and environmental reasons to transition away from fossil fuels. See the biofuels reactor that RTI International researchers are using to create gasoline-like hydrocarbon fuels from plant material and the challenges of creating biofuels.

RESEARCH TRIANGLE PARK—It may look like something straight from science fiction: a three-story-tall mass of pipes, support beams and machines. There are pipes of different colors, sizes and shapes. Rows of colored lights glow from control panels at the bottom. There’s a low hum coming from inside. 

Step outside however, and you find this mass of industry and technology housed in a very plain, nondescript building on the Research Triangle Park campus of RTI International. 

The contrast is interesting, But before we talk about what happens inside, you need to know why the building is here.  The mass of technology is part of the effort to develop enhanced biofuels technology.

“What that means is a non ethanol-based, non alcohol-based fuel that is a direct replacement for petroleum-derived gasoline and diesel range hydrocarbons,” explains David Dayton, Ph.D., Biofuels Director for RTI International.

Much of the research is funded by the U.S Department of Energy. Scientists are searching for a replacement for gasoline, which of course comes from oil.  Alternative fuels were all the talk when gas prices hit four dollars per gallon and higher.

The talk isn’t as frantic when the price is a lot lower.

However, energy independence and sustainability are important goals, so RTI’s scientists continue fine-tuning a process to economically and efficiently convert sawdust and wood chips into a transportation fuel.  The process can be adapted to any biomass, as long as there is carbon.

“We’re using heat, catalysts and time to convert things thermally into intermediates and then fuels,” adds Dayton. “So the nice thing is as long as there is carbon in it and it can be thermally converted, we can convert it. Which means the process can be applied to waste wood from sawmills, grasses and straws, agriculture residues, and the list goes on.”

In the case of the RTI system, sawdust is brought into the process and mixed in a reactor with a catalyst. The catalyst controls the chemistry in the heat transfer medium which drives the reactions.  The catalyst also flows like water and makes the mix into a fluid that is pumped into a reactor, heated and mixed.

Three different materials come out of the reaction.  The first is unconverted carbon or char, which is similar to what is in your grill for cooking.  The second is light brown water, call it leftover water, that still has some carbon in it.  The third is biocrude, which is the goal of the entire process.

“The materials we make in this group need to be evaluated and the work I do analyzes the material to see if it is working properly and doing their job,” says Kelly, an analytical chemist at RTI International. “Plus, any products that come from the work we do needs to be tested for quality.”

Everything is precisely measured, because while a small mistake early in the development of the biofuels process may not be a big deal, as the process is scaled up, that little mistake would grow larger and could be dangerous. And the key to the success of any biofuels process is the ability to refine a large amount of fuel.  

The bio-crude then goes into a standard refining process to make a hydro-treated fuel.  

“We’re using hydrogen to remove undesirable components that are in the early stage biocrude,” explains Nii Ofei Mante, a Research Chemical Engineer at RTI International.  He’s standing in front of another mass of pipes and tanks in a separate building.  Besides trying to improve the efficiencies of the process, he’s also trying to scale it up, to be able to make more biofuel.  

“We want to make as much as we can, but we need to produce precisely the hydrocarbons that fall within the gasoline and diesel ranges. In other words, we need to make gasoline and diesel fuel that will work in cars and trucks,” he said.

Engineers say there is no doubt the process works. But they caution that it is called an alternative fuel for a reason. Biofuels cost more than conventional fuel.  The process is competitive when gasoline costs around three dollars per gallon.  The low price of gasoline has stalled industry interest in alternative fuel research.

That means research is concentrating on maximizing the process to drive down the coast of making biocrude so it can be competitive with the existing technologies of refining petroleum into gasoline and diesel fuel. 

“We’ll always be at a challenge because we are starting with a raw material not optimized for a fuel, but we want to come up with the innovations we need to get around those technical barriers and ultimately make this cost competitive,” says Dayton.  

Still, the one advantage that can’t be dismissed with biofuels is the environmental benefit. Biofuels produce less pollution, and the carbon that is produced is absorbed by the grasses, plants, trees, etc. that will then be used to produce fuel.  You could call it a kind of “green circle.”

“There’s no doubt we can reduce the environmental greenhouse gas potential of transportation, “ says Dayton. “The cost issue is something we’re working on, but we’ve already shown the environmental improvements in transportation that can be made using biofuel feed stocks.”



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