Alcohol School: Yancey delivers D3Max project update

By Lisa Gibson | September 13, 2019

Minimizing feedstock cost is one rule for a successful cellulosic ethanol project, according to Mark Yancey, chief technology officer for D3Max. “That can be a very large component of your project costs.”

Yancey spoke Sept. 13 at Lallemand Biofuels & Distilled Spirits’ Alcohol School, held this week in Montreal. The final day of the event focused on cellulosic ethanol.

D3Max partnered with Ace Ethanol in Stanley, Wisconsin, to construct a cellulosic ethanol plant, which is expected to start up in October. Yancey said the D3Max development plan has always been to colocate with an existing ethanol plant.

In a cellulosic project, Yancey continued, avoid feedstock harvest and transportation, make sure it’s available year-round and has a high coproduct value.

Other rules Yancey shared from his experience included those in pretreatment: ensure high solids loading, a low-cost catalyst, and minimize inhibitor production. In Enzymatic hydrolysis, minimize enzyme cost, avoid dilution after pretreatment, and use hemicellulase and cellulase enzymes. In fermentation, ensure both C5 and C6 sugar fermentation, use a robust and low-cost yeast, and aim for a high product yield.

Yancey said issues a cellulosic ethanol plant might face include: feedstock supply, feedstock cost, capital cost per gallon of ethanol, ethanol yield, coproduct value, wastewater and project financing.

The feedstock for the D3Max system is wet cake, making a pretreatment step crucial. The wet cake goes into a reactor, then a clash tank, then to fermentation, beer column, and to dehydration or decanters to recover ethanol or produce feed.

“This is considered separate processing,” Yancey said. “There’s no mixing of the starch or sugars between the two plants. That makes us what EPA calls separate processing.” The separate processing status makes permitting much easier, he added.

Corn oil yield is expected to be 1.2 pounds per bushel, with a dried distillers grains with solubles yield of 10.5 pounds per bushel. That’s an improvement of DCO yield from 0.7 pounds per bushel from a standard dry mill ethanol plant, Yancey said, and a decrease of DDGS from 14 pounds per bushel, but an increase in protein of 27 percent.

“Ace is very happy with the results,” Yancey said.

Key players in the project include Ace and D3Max, as well as Fagen Inc., AdvanceBio, Fluid Quip Process Technologies, DSM, Lallemand and Whitefox Technologies.

The D3Max plant is expected to produce about 3.4 MMgy, increasing Ace’s overall yield of 2.9 gallons per bushel to 3.1 gallons per bushel, Yancey said.

In response to questions about starch in feedstock and the effects of nutrients, Yancey said, “when this is all up, we’ll need to reoptimize the whole facility.

“Everyone is waiting for our plant to start up. The proof will be in the actual commercial demonstration.”