KiOR: The inside true story of a company gone wrong

Needed: a new catalyst and heat-transfer material

The BIOeCON concept, which became the proposed KiOR reactor technology, was to employ a new (non-FCC Catalyst), a synthetic inorganic clay-like material, which exhibited certain deoxygenating activity for producing low oxygen-containing Bio-oils. The regular FCC Catalyst used by Vasalos was used widely in oil refineries to crack petroleum feedstocks to light hydrocarbons and make gasoline. But the regular FCC catalyst would leave too much oxygen in the bio-oil, making it unsuitable for upgrading.

The material in question? Hydrotalcite, or HTC.

It was an anionic synthetic clay of the mineral class of double-layered hydroxides. Both O’Connor and Stamires had, and in many cases, together with Prof. William Jones from Cambridge University in UK, and with many others at AKZO NOBEL and subsequently at Albemarle, done extensive R&D work using LDHs as catalysts or sorbents in several types of oils upgrading and conversion, and commercial oil refining and upgrading applications.

Here was the weakness of the concept, which would turn up in testing.

“By combining in one-pot reactor these two distinctly different reactions,” Stamires would later recall, “the thermolysis (a heat transfer/physical reaction) with the deoxygenation/decarboxylation (a chemical reaction), the efficiencies and selectivities of both reactions would be highly compromised and distorted. It produced more water, gases, coke and char.”

As Stamires would tell The Digest:

“To achieve a high efficiency liquefaction of biomass, these small particles must receive a high heat flux in a short time, following with a quick efficient quenching of the Bio-oil vapors. To accomplish this, we needed to use a material which has a high heat capacity and also high heat transferring properties, a good heat conductor. As was ascertained later on, the anionic type of clays, such as the Hydrotalcite, has a very low heat capacity and heat conducting properties. That’s because of its highly porous crystal structure, and low bulk density.”

From the start, then, hydrotalcite was the wrong material to use, The Digest was told.

But testing would turn up another problem. Hydrotalcite is a very active catalyst, used primarily for promoting oil gasification type reactions; the surface gets quickly coated with heavy tar like carbonaceous materials, which further reduce its heat conducting properties when present in a one-pot biomass liquefaction reactor.

But that wasn’t all.

Hydrotalcite was found to have a very high gasification catalytic activity and very efficiently converted most of the biomass oxygen and carbon to carbon monoxide and carbon dioxide gases, and water. Leaving only a small portion of the biomass carbon and hydrogen to form liquid hydrocarbon bio-oils. So, yields with HTC were doomed to be low — in addition to the tarring problem and the heat conduction issue.