Retrofitting for Alternatives

Colorado-based Gevo Inc. has developed a three-part technology package for retrofitting existing ethanol plants to produce biobased isobutanol. The design allows ethanol producers to leverage existing infrastructure to produce a multitude of alternative fuels and high-value end products.
By Erin Voegele | September 15, 2009
Gevo Inc. was founded four years ago by three California Institute of Technology (CalTech) researchers with the goal of developing an advanced biofuel that could sustainably and effectively replace petrochemical products."What we are doing is developing second-generation biofuels," Gevo's Vice President Brett Lund says. "To do this, we wanted to develop a technology that could be used as a retrofit in existing ethanol plants."

The result is a three-part technology package that Gevo has developed that essentially allows current ethanol producers to leverage existing infrastructure to produce higher value end products. This is accomplished through a minor retrofit that requires a small, one-time capital investment.

Since its inception in 2005, Gevo has attracted an impressive list of investors, including Khosla Ventures, Richard Branson's Virgin Green Fund, Burrill & Company, and the French oil and gas company Total. "[Total's] investment really gave us a lot of commercial validation, in our opinion," Lund says. "They are one of the largest oil and gas companies in the world; they've gone out and looked at all the alternative technologies that are out there, and chose to invest in Gevo."

The Technology
One primary component of Gevo's technology package is the company's genetically modified biocatalyst. The biocatalyst is a strain of yeast that has been biologically engineered to produce isobutanol rather than ethanol. According to Lund, Gevo's researchers essentially shut off the yeast's ability to produce ethanol and engineered it to produce isobutanol instead.

The pathway of the biocatalyst, or the way in which the biocatalyst is able to make isobutanol, was licensed by Gevo from the University of California, Los Angeles. The company has also licensed other intellectual property relating to the biocatalyst from CalTech and maintains strong research relationships with both institutions.

Another primary component in Gevo's technology is the method the company has developed to separate the isobutanol from the biocatalyst as it is produced. Gevo has patented this separation technology known as Gevo Integrated Fermentation Technology.

Historically, there have been two main issues with biobased isobutanol production: intolerance of the biocatalyst to high levels of isobutanol and problems with effectively and economically separating the isobutanol from water. Through the development of GIFT and its proprietary biocatalyst, Gevo has been able to overcome both of these issues.

"The problem with butanol in the past has been that as soon as the biocatalyst starts producing butanol, the butanol becomes toxic and kills it," Lund says. "What we've done is genetically modified [the biocatalyst] to make it produce a lot of butanol and make it very tolerant so it doesn't die.

"We've also developed [our GIFT technology] to separate the butanol from the organism as it is produced, and that further helps in assisting the organism so it doesn't die while it's producing fuel," Lund continues. That innovation in engineering also negates the issue of water separation. "As the fermentor is producing butanol, we separate it from the fermentation . in a pure form. So, we are basically pulling it off as it is produced," he says. "That allows us to avoid having to do very costly water separations."

Gevo's technology is feedstock flexible and has been designed to utilize all traditional ethanol feedstocks as well as cellulosic biomass. "We've developed our technology to work using corn, sugar and cellulosic biomass," Lund says. "We don't actually convert cellulose into sugar, but we have developed our technology to work with mixed sugars from cellulosic biomass."

The final primary component of Gevo's technology involves the conversion of isobutanol into a wide variety of end products. "We have developed technology to convert isobutanol into a number of hydrocarbons," Lund says. "We can turn it into renewable gasoline, renewable diesel or renewable jet fuel." Isobutanol can also be converted into a number of chemical products, including rubbers, plastics, polymers and fibers.

The end products can be produced in two ways: the conversion component of the technology can be incorporated into the ethanol plant during the retrofit, which would allow the facility to produce renewable gasoline, jet fuel or diesel onsite, or the isobutanol could be shipped to a central location for processing.

Demonstration-Scale Production
The process used to retrofit an existing ethanol plant to utilize Gevo's technology is relatively simple. "To complete the retrofit, we use all of the existing equipment that is in [the plant]," Lund says. "We also add a few pieces of equipment and bring in our biocatalyst. So, instead of using the yeast that is used to make ethanol, we use ours which is used to make isobutanol." Once the retrofit is complete, the plant operates essentially in the same way as a traditional ethanol plant.

To date, Gevo has scaled up to pilot-level production at its facility in Denver. Gasoline produced at the plant has been tested in vehicles and, according to Lund, jet fuel produced at the facility conforms to ASTM standards and has successfully entered tier two testing with the U.S. military.

A larger demonstration-scale pilot project is currently underway at ICM Inc.'s 1 MMgy pilot facility in St. Joseph, Mo. The two companies began working together on the project in October 2008, and ICM's pilot plant is expected to begin producing isobutanol in late September.

"We partnered with ICM because ICM has designed and engineered most of the ethanol plants in the United States," Lund says. "If you want to make any modifications to an ICM plant, you need to work with them to do it. In our opinion, they are one of the best design and engineering groups in the ethanol industry."

According to Brian Burris, ICM's general counsel, ICM's reputation for quickly bringing new technology to market also served as an attractive factor to Gevo when it was forming a relationship with his company.

ICM's St. Joseph plant has primarily been used to test ethanol production processes. "We test different sorts of feedstocks, different sorts of yeast, and different sorts of enzymes at our pilot plant," Burris says. "We do that for our own research and development, and we also do that for hire."

According to Burris, in addition to the retrofits required to employ Gevo's technology, ICM installed some additional safeguards to the plant. "One of the things that we did since St. Joseph is a food facility is we put in some very special safeguards so there can be no possible contamination of the food facility," Burris says.

The relationship formed between Gevo and ICM is exclusive. "They have committed contractually to work with us exclusively in the field of butanol," Lund says. "Likewise, they are our exclusive partner for retrofitting ICM-designed plants."

While this project involves fuel that can be produced as an alternative to ethanol, Burris notes that ethanol is still ICM's primary business. "ICM is an ethanol company that's where we've got our roots and we are still very bullish on ethanol and think that it's got a good future," he says. "But, to the same extent, the industry is depressed right now and people are looking at all sorts of different ways to improve margins. This might be an attractive play for someone who wants to bet that butanol will be a successful product."

Through the St. Joseph pilot project, the two companies are working to develop an engineering package that will be used to retrofit other ICM designed facilities. Once the pilot plant is up and running, it will also be used to demonstrate the technology to the owners of other ICM facilities. These owners will be able to tour the pilot facility and see exactly how the plant was modified and how it works. "That will really give them a lot of confidence that the same can be done in their plants as well," Lund says.

In addition to proving that the technology can be successfully scaled-up, the pilot facility will also provide Gevo with access to large quantities of fuel that can be used for testing and evaluation purposes.

According to Lund, there are a variety of advantages to retrofitting an ethanol plant to produce isobutanol the foremost being flexibility. A plant retrofitted with Gevo's technology will be able to produce isobutanol, which can be used as a fuel blendstock, much like ethanol is.

Adding even more flexibility to the technology, a retrofitted ethanol plant could still produce ethanol. This would be accomplished by simply turning off the additional pieces of equipment that were added to the plant during the retrofitting process and replacing the biocatalyst with traditional yeast.

"There is really a lot of optionality," Lund says. "You can produce ethanol; you can produce biobutanol; and you can take biobutanol and turn it into any of those hydrocarbons gas, jet, diesel or chemical. So, you really have a lot of opportunity to arbitrage the market depending on what you want to produce, what's in demand and what's selling for a good price."

One benefit of isobutanol is that it overcomes many of the limitations that face ethanol, according to Lund. "Butanol is not water soluble, which means that it can be sent in existing pipelines and the existing infrastructure that petroleum is shipped in," he says. "Butanol also behaves more like a hydrocarbon, which lends itself to using chemistry on it to convert it into those other fuels."

With the development of its demonstration facility nearly complete, Gevo is now working towards larger scale production. "Currently, we are looking to acquire ethanol plants, or partner with ethanol plants, to retrofit them to utilize our technology and start producing fuels on the commercial level," Lund says. He estimates the first large-scale production facility will be up and running in 2011.

The company will also likely consider projects involving new construction in the future. "The technology works equally as well in greenfield plants or existing ethanol plants, and both are definitely on the agenda," Lund says. "The design and engineering for the greenfield plants will also be done by ICM, so we'll have two packages."

The technology is designed to be employed at plants with annual production capacities ranging from 25 MMgy to 100 MMgy. Gevo's projected estimates currently show that it will cost about 30 cents per gallon to retrofit a facility. "If you had a 100 MMgy plant, it would be about $30 million to complete the retrofit," Lund says.

While Gevo plans to bring the technology to market itself by acquiring, retrofitting and operating ethanol plants, Lund says the company will also seek to license the technology to third parties.

According to Lund, Gevo expects to see strong interest in its technology due to its potential to benefit ethanol producers currently struggling due to prevailing market conditions. In addition to interest from U.S. producers, Lund says Gevo is also seeing strong international interest develop, particularly in Brazil and Europe.

"[Those employing Gevo's technology] will be able to leverage all existing infrastructure and produce a product that's worth considerably more than the one they are producing now; which helps them to achieve a much higher margin and return than they are getting producing ethanol," Lund says. Those employing Gevo's technology will also benefit from its optionality. "There is a lot of flexibility in what they can produce," Lund says. "If they want to produce ethanol, they can produce ethanol; if they want to produce butanol, they can produce butanol; and if they want to produce any of these other hydrocarbons, they can produce those. That gives them a lot of flexibility and helps with market fluctuations."

"It seems that given the current environment where a lot of ethanol plants out there right now are struggling this is a way to help leverage their existing infrastructure and investment and help them return to higher margins on a different fuel," Lund says. EP

Erin Voegele is an Ethanol Producer Magazine associate editor. Reach her at or (701) 373-8040.

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