Gevo currently makes isobutanol from corn at its plant in Luverne, Minn., but its process has always had the flexibility to adapt to other feedstocks. The newly announced today uses forest residuals—the wood scraps that are left over from logging operations—providing a value creating recycling opportunity for waste wood that is traditionally left in the forest, potentially becoming a forest fire hazard.

The company has previously announced the testing and use of its alcohol-to-jet fuel derived from its corn-based isobutanol in conjunction with major airline partners and the US military. (E.g., earlier post, earlier post, earlier post.)

Gevo has adapted its patented Gevo Integrated Fermentation Technology (GIFT) to convert the cellulosic sugars from wood into renewable isobutanol, which is then converted into alcohol-to-jet-synthetic paraffinic kerosene (ATJ-SPK) blendstock.

Broadly, the isobutanol is dehydrated over an acidic catalyst to produce isobutylene, which is then further reacted to product mixtures of longer chain aliphatic hydrocarbons. A portion of this material is reacted separately to form high density aromatic compounds. Hydrogen gas, a byproduct of the aromatization reaction, is used to remove unsaturated bonds in the aliphatic material.

The hydrocarbons then are blended in proportions that can meet all ASTM standards for fuels: isooctane is a dimer of dehydrated isobutanol and is a major component of the premium value alkylates, a key gasoline component; a trimer of the isobutylene (dehydrated isobutanol) is a jet fuel blend stock; a polymer of four and five isobutylenes can make a diesel blend stock.

[Ed. note: Isobutylene is also called isobutene, which Global BioEnergies produces directly via fermentation of sugars and then processes separately to produce Audi’s e-benzin. Earlier post.]

The Gevo’s cellulosic isobutanol production will be conducted at a demonstration facility in St. Joseph, MO, that the company jointly operates with ICM Inc. The ATJ-SPK will be produced in Silsbee, TX, at the demonstration facility the company operates with South Hampton Resources.

Contents of renewable jet fuel (SPK = synthetic paraffinic kerosene; HEFA = Hydro-processed esters and fatty acids) compared to conventional Jet A, JP-8. Source: DOE. Click to enlarge.

There are significant economic and environmental benefits of renewable jet fuel, which makes it a great market for Gevo. This announcement demonstrates the flexibility of our technology and reinforces our technology leadership. The next two milestones for renewable jet fuel are the approval by ASTM and the scheduled commercial test flights. Our team is actively engaged in both of these activities.

—Dr. Pat Gruber, Gevo CEO

NARA is a five-year project supported by the US Department of Agriculture, National Institute of Food and Agriculture, and comprises 22 member organizations from industry, academia and government laboratories. Its mission is to facilitate development of biojet and bioproduct industries in the Pacific Northwest using forest residuals that would otherwise become waste products. A key task of the project is to evaluate the economic, environmental and societal benefits and impacts associated with such developments.