Going for the Fiber

Quad County Corn Processors is working toward production of both grain-based and cellulosic ethanol from the same feedstock.
By Holly Jessen | October 05, 2012

Travis Brotherson, plant engineer at the 30 MMgy ethanol plant in Galva, Iowa, wasn’t even thinking about cellulosic ethanol when he stumbled upon a path to fermenting corn fiber. It started with an investigation into measuring residual starch in distillers grains that led him to experiment with breaking down additional starch in the coproduct. That’s when he realized the treatment was yielding more sugar than expected by also breaking down fiber. “At first, it was almost confusion, because we weren’t expecting these results,” he tells Ethanol Producer Magazine.

Three years later, Quad County Corn Processors is poised to begin construction on the bolt-on cellulosic ethanol technology invented by Brotherson. The project will cost an estimated $8.5 million, $5.7 million of which will come from two separate grants awarded by the U.S. DOE and the Iowa Power Fund. The goal is to begin construction in the spring and reach operational status in the third or fourth quarter of next year. “There’s multiple hurdles that have to be crossed and any one of those hurdles could slow it down, but that’s our goal today,” says Delayne Johnson, plant general manager.

Once it’s operational, Quad County expects to produce an additional 1.8 MMgy of cellulosic ethanol from the same amount of incoming corn. That’s a 6 percent increase in yield resulting from making the glucose in the fiber available for fermentation. “We have actually shown the ability in our lab tests and our pilot tests that we can produce more, but we are kind of taking our bottom number from a statistical standpoint,” Brotherson says.

But that’s not all. The process will also result in 1.6 pounds of corn oil per bushel of corn, up 1.1 pounds from the 0.5 pounds the ethanol plant is extracting currently. The process will alter the plant’s main coproduct enough that it won’t really be considered distillers grains anymore, Johnson says. Minus the fermented fiber, output will decrease to about 85 percent of what is produced today. The new coproduct, which will have similarities to corn gluten meal, will be sold under a yet-to-be determined name as a high-protein, low-fiber animal feed that is expected to be especially attractive to monogastric feed markets.

The company is first focusing on proving out the patent-pending technology on a full scale. Also on the to-do list is making it available to other corn-ethanol producers for licensing. “We really see this as being able to be applied to any ethanol plant out there, no matter where you’re located and no matter what feedstock you are using,” Brotherson says, adding that the company has begun the testing of other grain-based feedstocks containing fiber. Right now, they call it adding cellulosic ethanol—or ACE—but that could change. “We’ve spent more time on the process than we have the name,” he says.

Quad County’s process doesn’t involve fractionation. Corn fiber is fermented together with corn starch, resulting in a single stream of ethanol. The new equipment comes into play midstream, with the existing process occurring unaltered at the front and back end of things. “There is literally one pipe going out and one pipe in, if you will,” Johnson says. In addition, the bolt-on cellulosic portion of the plant is all components of existing technology. “It’s not a new widget,” he adds.

Fortunate Chain of Events
Something that makes Quad County stand out in the crowd is its R&D facility, which is located in a separate building on site. In 2008, when Brotherson was hired as plant engineer, the building was in use by another company that eventually suspended its operations and sold off its equipment to the ethanol plant. Having access to both laboratory equipment and a pilot-scale fermentation system is an unbeatable combination, Brotherson says. The lab component helps with churning out a lot of data, analogous to using a shotgun. “You try a lot of things and you kind of get an idea of what direction you need to shoot next,” he says. At the pilot scale, on the other hand, random experimentation would get expensive. “You kind of need to have an idea of what you are aiming for when you get there,” he says.

To date, the company has conducted about 1,000 lab-scale fermentations and 40 in the pilot plant’s two 200-gallon fermentors. Taking what had been learned so far, Brotherson then designed equipment that allowed Quad County to conduct about a dozen 5,000-gallon fermentations in the main plant. That all culminated in a one-time test at full scale—about 250,000 gallons. All that testing makes Brotherson confident ACE will be successful commercially. He’s excited for construction to begin so the concept can be proved out. “This is kind of one of those things where it’s looking like a home run hit and you just don’t really expect that you are going to end up finding something like that,” he says.

The R&D facility has been helpful in developing ACE, of course, but Johnson says that isn’t the only benefit. The company has also used it to test out potential changes for traditional corn-ethanol production, such as new enzymes, different dosages or temperature changes. “We can check out a lot of different things on a small-scale basis without having to experiment on the full-scale basis,” he says. And, Quad County isn’t the only company that has taken advantage of the facility. Although he can’t say which ones due to confidentially agreements, some of the major enzyme companies have contracted with the ethanol plant for R&D work conducted there. “It would be fair to say that we have done work for three out of the five enzyme companies,” he added.

Cellulosic enzymes are another key factor in the development of the technology, Brotherson says. His initial work on it resulted in a process that wasn’t quite financially feasible. “The thing that we needed was a cellulosic enzyme with a certain amount of activity that would come in at a certain price point,” he says. Two weeks later a new enzyme was introduced. “Since then there’s been another generation or two of enzymes that have come out,” he says. “Each one just kind of makes the process a little bit better and more profitable along the way.”

The way Quad County looks at it, fermenting corn fiber is a good idea for that facility as well as the industry as a whole. First off, it will add to plant profitability. While it’s true there’s a cost to adding additional equipment, processing ingredients and energy expenditures, additional net income will also be generated from the additional cellulosic ethanol and corn oil produced. And, if a ready market is found for the new corn feed coproduct, it could command a premium. “We’re certainly selling more high-value product from the same kernel of corn,” Johnson says. Another point in corn fiber’s favor is the fact that the system of harvesting, transporting and storing corn is well established. “It is already here, it’s in the plant, so there’s no procurement needed,” he says.

Brotherson and Johnson both say they are supportive of efforts to produce gallons from noncorn feedstocks. Corn fiber, however, is a pathway to producing gallons in the near future, in order to start fulfilling the requirements of the renewable fuel standard. And, ultimately, that’s going to help move the cellulosic ethanol industry forward, hopefully drawing the cost of enzymes down as those companies start to see returns on R&D investments, Brotherson says.

Author: Holly Jessen
Features Editor of Ethanol Producer Magazine
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