Corn for Hydrocarbons

Add-on technology developed for corn ethanol plants
By Holly Jessen | August 15, 2011

Rather than retrofitting a corn-ethanol plant to produce i-butanol, n-butanol or use other novel fermentation technologies, three companies are collaborating to turn a traditional ethanol plant into a true biorefinery producing multiple fuels and coproducts.

Luca Zullo, principal of VerdeNero LLC outlined a vision incorporating work that his company, JetE LLC and Gas Reaction Technologies Inc. have done towards expanding the ethanol industry past the limiting factor of the blend wall to produce ethanol and distillers grains as well as drop-in replacement fuels and chemicals.. Zullo was one of many presenters at the Biomass ’11: Renewable Power, Fuels and Chemicals Conference held July 26-27 in Grand Forks, N.D. “We believe that the infrastructure and market position established by the corn ethanol industry represents the most logical base on which to build a diversified biorefining industry,” Zullo said, adding that although the U.S. corn ethanol industry is frequently misunderstood and misrepresented, it’s the only domestic renewable fuel industry to reach significant scale and make a measurable impact on the U.S. fuel supply.

Unlike other biorefining proposals, the model Zullo presented keeps the ethanol plant in place as is, including production of distillers grains in its current composition and at its current value. Two additional technologies could be added to an existing ethanol plant, one of which is commercially ready now and the second is development.
JetE, a St. Paul, Minn.-based company, converts low quality corn oil from the ethanol plant, as well as waste vegetable oils and fats when available, into drop-in paraffinic green diesel and green jet fuel. Zullo called it a simple process to make better biodiesel than biodiesel. “We are ready for commercial deployment,” he added.

Technology from Santa Barbara, Calif.-based GRT uses ethanol as the feedstock to produce hydrocarbon fuel. Although the technology is in an earlier stage of development and is three to four years from commercial deployment, it isn’t completely unknown. Mobil Oil was doing something similar in the 1980s, he said.

Put together at an ethanol plant, the two technologies can turn a 100 MMgy ethanol plant into a 50 MMgy ethanol plant also producing 60 MMgy drop-in replacement fuels. Or, the same plant could be converted completely to 90 MMgy drop-in replacement fuels only. In both cases, the plant would continue to produce distillers grains.

Zullo talked about several advantages of full integration of an ethanol plant. First, the JetE and GRT technologies can use waste heat from the ethanol plant. Water can also be recycled in the process. Finally, on average, the integrated biorefinery produces more energy per bushel of corn.

He also pointed out problems with retrofitting ethanol plants for i-butanol, n-butanol, alkanes and other novel fermentation technologies. It’s uncertain if these products will be accepted in the marketplace, he said. It’s more complex to produce these fuels for them to become a real drop-in fuel and their value and pricing is unclear at this time. In addition, these technologies are highly proprietary and costly. Although distillers grains are produced, it’s likely this source of revenue will be lost, Zullo said, due to the toxicity of the fuels produced and the use of genetically modified organisms. 

—Holly Jessen