Turning waste into gasoline

It’s a topic of conversation for environmentalists and commuters alike: is there a sustainable alternative to gasoline? In North Carolina’s research triangle, scientists are looking to answer that question.


It's a topic of conversation for environmentalists and commuters alike.

Is there a sustainable alternative to gasoline?

In North Carolina's Research Triangle, scientists are looking to answer that question.

Here's their story.

It may look straight from science fiction.

But it's a state-of-the-art industrial setup housed in a very nondescript building.

It's on the Research Triangle campus of RTI International.

But before we talk about what happens inside, you must first know why it's here.

This is the story about the search for alternative fuel.

The technology that we're trying to develop is what they refer to as an advanced biofuels technology.

What that means is it's a non-ethanol-based, non-alcohol-based fuel that is a direct replacement for petroleum-derived gasoline and diesel range hydrocarbons.

Scientists are searching for a replacement for gasoline, which, of course, comes from oil.

Alternative fuels were all the talk when gas prices were this high -- Check the price -- and even higher.

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

Still, 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 materials that we make in this group need to be evaluated.

And the work I do analyzes the materials to let us know if they're working properly, doing their job.

And also the products that come from the work that we do need to be tested for quality.

The process can be adapted to any biomass as long as there's carbon.

So we're using heat, catalysts and -- and time to kinda convert things thermally into intermediates that can be upgraded into fuels.

The nice thing about that is as long as it has carbon in it and it can be thermally converted, we can use it.

So it applies to a whole range of feed stocks from woody biomass that you would use, perhaps, in like a pulp mill or for paper production, byproducts from that process, grasses and straws that are grown purposely for biofuels, agricultural residues like corn stalks and stover.

So here's what happens to the sawdust.

We start with our feed stock, which, in this case, is just sawdust, woody biomass that's gone through a process.

We mix that in a reactor with a catalyst, which, as you can see, flows similar like water.

It's fluidizable.

So the catalyst is not only controlling the chemistry of the process, but it's also providing the heat-transfer medium that can actually drive the reactions.

So we take these two materials in the reactor, heat 'em up, transfer 'em around.

And then the products from there are three different materials.

First one is unconverted carbon or char.

This is much like you would see charcoal in your, uh, in your regular charcoal grill for cooking.

We also make an aqueous stream, which is, as you can see, somewhat colored and potentially dirty.

But there's a lot of carbon in here that we're trying to recover as well.

And then the third material is what we're interested in.

And that's our bio crude.

This is our organic fraction.

Researchers wanted to recover even more of the lost carbon.

But the bio crude then goes into a standard refining process to make a hydrogen-treated fuel.

We're using hydrogen to move undesirable components that are in the intermediate to produce precisely hydrocarbons that fall within the gasoline and diesel ranges.

Engineers say the process works.

But it's called an alternative fuel for a reason.

Biofuels cost more than conventional fuel.

The process is competitive when gasoline costs about $3 per gallon.

Our RND targets are all focused on maximizing the process to ultimately drive down the cost so that we can become cost competitive with existing technologies.

We're always gonna be challenged because we're starting off with a raw material that's not optimized for fuel production.

But that's the goal -- to process technology development -- is to really optimize that process, come up with the innovations we need to get around those technical barriers and then ultimately make this cost competitive.

But the one thing that we do have an advantage with developing biofuels is the environmental footprint of what we're trying to do.

We can actually reduce the environmental greenhouse- gas potential of transportation.

And that's one of our, you know, targets for biofuels is just to really focus on 'How can we environmentally improve transportation, you know, in the country using -- using these biofuels feed stocks?'