Chevron’s Forgotten Biofuels Wonder-Tech Gets a Second Life at Iowa State

by Jim Lane (Biofuels Digest) You may recall that The Bloomberg investigative team of Ben Elgin & Peter Waldman in 2013 published an expose on Chevron claiming that the company had developed — then buried — a Catchlight Energy project that could profitably make renewable gasoline at $2.18 per gallon?

Originally the venture was intended to build 17 plants by 2029, making 2 billion gallons of renewable fuel, starting with a $370 million commitment by 2013 and a first commercial plant in 2014. The technology used solvent liquefaction to make bio-oil, which could then be upgraded to fuel-grade at a Chevron refinery.

The Bloomberg report pointed to an internal Chevron report, written in 2009, that concluded it would be cheaper to buy renewable energy exemptions than make renewable fuel. And, according to Bloomberg, a few months after the report appeared, Catchlight Energy’s budget to deploy the technology was scaled back.

In the Digest’s reporting, we cautioned that the tech was, at the time it was put on the back burner, at pilot stage. What happened to it?

Today, the solvent liquefaction tech is installed and operating at Iowa State’s BioCentury Research Farm in a joint project with Chevron, still at pilot stage, converting biomass such as quarter-inch wood chips into a bio-oil that can be processed into fuels or chemicals and a biochar that can enrich soils.

It doesn’t have a name, so we’ll call it Chumbawumba, after the group behind the 90s hit Tubthumping and its hypnotic “I get knocked down, but I get up again, you’re never going to keep me down” chorus.

The Chevron-Iowa State collaboration actually got underway in 2013 when Chevron moved its $1.4 million Small Continuous Liquefaction Unit from Houston to the research farm just west of Ames. The company was looking for a research partner to develop the plant for continuous production and to build a system for recycling solvent back into the production process. As part of the agreement, Chevron has donated the pilot plant to Iowa State.

“In pyrolysis, the molecules have to be broken down into small enough pieces so they they can volatize” explains Robert Brown, the Anson Marston Distinguished Professor in Engineering at Iowa State University and Director of the Bioeconomy Institute. Of course, that’s only the mild-mannered alias of the Godfatha of the Pyromaniax.

“In solvent liquefaction, they don’t have to break down to that extent, they are in a solvent that moves out of the reactor, so you see a different set of molecular weights. Also, the carbohydrates in solvent liquefaction can be converted in material that is more useful as a starting point for making fuels, than is sometimes the case in pyrolysis, so you can get a better yield.”

“Well, one thing that is interesting in this process,” says Brown, “is that we are trying to produce the solvent that we use. So we have an organic solvent, instead of water. We use some of the product as a solvent, and generate more of it with the process, and then we take some off and we recycle the solvent. In practice, we are studying how to optimize the process of distinguishing the organic compounds we have produced versus the organics that are the solvent.”

You have ontinuous solvent liquefaction, product separation with direct solvent recycle and online solids removal. You get a bio-oil that is low in oxygen and therefore more stable than other bio-oils. Well, sorta on that oxygen content. Back to that in a sec.

25% oxygen content? Ouch! That’s more than any known hydrotreating technology installed at a refinery can handle. READ MORE and MORE (Iowa State University)