Taking Corn Fiber to the Max

In Stanley, Wisconsin, Ace Ethanol LLC is becoming a pacesetter in the corn fiber-to-ethanol race after installing D3MAX technology, which gives the plant a strong advantage, both with cellulosic RINs and, potentially, the low-carbon fuels market.
By Tom Bryan | July 14, 2020



Ethanol Producer Awards



When the U.S. EPA approved Ace Ethanol’s Part 80 registration for corn-fiber-to-ethanol production this spring—qualifying the facility to generate D3 RINs—it was not just another project milestone, but a critical validation and definitive green light to go.  

“Securing that D3 approval was never in question, but it was obviously a required step in our project schedule,” says Neal Kemmet, CEO of Ace Ethanol LLC. “Getting cleared to generate D3 RINs wasn’t a ‘mission accomplished’ moment for us, but a gateway to the next stage in our ongoing cellulosic journey.”

To participate in the U.S. Renewable Fuel Standard, and generate renewable identification numbers, or RINs, producers must meet the registration requirements in Title 40 CFR Part 80 of the RFS. Landing that critical EPA approval in March, Ace was cleared to start optimizing the economics of cellulosic ethanol production—generating one D3 RIN credit for each gallon of output from its newly commissioned D3MAX corn-fiber-to-ethanol plant in Stanley, Wisconsin. 
Three months into it, despite the pandemic and economic downturn, ACE Ethanol is producing appreciable volumes of cellulosic ethanol, running the plant at roughly 80 percent of design capacity and 70 percent of design yield. And while the facility will climb toward capacity for some time, it is already one of the highest-volume cellulosic ethanol plants in the world. In fact, the D3MAX plant is approaching a rate of nearly 3 MMgy, increasing Ace’s overall yield to more than 3.1 gallons per bushel. The plant’s commissioning and early operation has not been without unique challenges: equipment upgrades and process tweaks have occurred along the way. But Ace has not reported a substantive shutdown of the D3MAX plant, and is producing tens of thousands of gallons of cellulosic ethanol weekly. While Ace is not revealing exact production numbers, the new process will push the plant’s corn oil yield up to about 1.4 pounds per bushel (from 0.9 pounds per bushel), while its distillers coproduct has decreased in volume and increased in protein concentration.

Construction of the plant, which Ace owns and operates, utilizing the patented D3MAX technology under license, began in late 2018. “Ace did a fantastic job commissioning and starting up the plant,” says Mark Yancey, chief technology officer of D3MAX, reflecting on the tough winter that ensued after project builder Fagen Inc. broke ground. Yancey says those first months were fraught with cold-weather challenges—snow and ice slowed work to a crawl at times—but the work progressed, day by day, through the second, third and fourth quarters of 2019, until it was substantially complete in January and commissioned in early 2020. 

For Yancey and his team at D3MAX, the commissioning of the plant was a long time coming. Patents on the trailblazing technology had been filed more than a decade earlier, but the platform wasn’t introduced to the industry until capital investment in 2016 kick-started its demonstration at pilot scale. “With that equity, we were able to design and build a portable, skid-mounted pilot plant,” Yancey says, explaining how exploratory meetings with Ace resulted in the ethanol plant’s directors agreeing to host the pilot plant, running extensive testing throughout 2017.

“I think we ran into unexpected things most every week, but we learned from them, and we worked through many phases of development in order to come up with what we think is an ideal process for converting corn fiber to ethanol,” Kemmet said prior to construction.

Ace set specific performance goals for the pilot testing, and ultimately D3MAX satisfied those marks. “The D3MAX pilot process was able to meet or exceed our performance goals,” Kemmet said after the pilot tests were complete. “Based upon the pilot testing, we believe D3MAX has the potential to significantly improve our company’s financial performance. We are in the process of finalizing pilot testing and will be working to ensure that we can seamlessly integrate the technology into our existing process. Once we have all the pieces in place, the final decision on installation will be made by our board of directors and the Ace membership.”

With the pilot demonstration achieving prescribed thresholds, Ace’s board voted in the spring of 2018 to approve a full-scale construction project. Work began on the detailed design of the plant that summer and most of the process engineering was complete by the time excavation and foundation work got underway that fall.

Yancey says Ace was the perfect partner for a novel cellulosic ethanol plant. “They were engaging and candid throughout the entire process,” he says. “Like every major construction project involving a new technology, there were frequent challenges and, of course, moments of anxiety, but the commissioning was largely smooth, and I believe we’ll look back on this project as a huge success—and the first of many D3MAX installations.” 

Because D3MAX uses wet cake as a feedstock—with no mixing of starch or sugars between the main plant and the new wing—it’s considered “separate processing,” which eliminates the need for mandatory third-party verifications. According to Yancey, the D3MAX process is the only corn kernel fiber-to-ethanol process on the market that will not require an independent engineer to validate the cellulosic ethanol production every 500,000 gallons of cellulosic ethanol produced. With the D3MAX process, cellulosic ethanol gallons can be measured directly, avoiding the cost of recertification required by EPA for co-processing, or in-situ, corn kernel fiber processes. Currently, all other corn kernel fiber technologies available require that intermittent re-certification.

Key players in the project, in addition to Ace, D3MAX and Fagen, included AdvanceBio, Fluid Quip Process Technologies, DSM, Lallemand and Whitefox Technologies, which installed a membrane-based ethanol recovery technology at the plant, resulting in significant energy savings for the integrated facility. “We pulled together a great team for this project, and the end result is a working cellulosic ethanol project—a benchmark achievement for our industry—and a facility that is positioned to be one of the most efficient, highest-yielding ethanol plants in the world,” Yancey says.

ACE Ethanol was nominated for this award by John Nelson of BBI International.