NABCE 2014 comes to an end with Poet-DSM fantasy fuel plant tour

By Katie Fletcher | October 16, 2014

A sold-out bus trip that traveled three hours southwest of Minneapolis, Minnesota, to Emmetsburg, Iowa rounded out the 2014 National Advanced Biofuel Conference and Expo. The closer the bus came to Emmetsburg, the more cornfields dominated the scenery out the window. Acres of golden corn stalks ready for harvest alluded to the tour bus’s destination, POET-DSM Advanced Biofuel LLC cellulosic ethanol plant, or Project Liberty, a joint venture of Royal DSM and Poet LLC.   

Just last month Biomass Magazine reported from the grand opening ceremony celebrating the completion of the first commercial-scale cellulosic ethanol plant in the U.S., a decade in the making. The NABCE tour attendees and future visitors witness the sprawling campus upon arrival hosting Poet’s traditional corn ethanol plant, Poet-DSM’s recently commissioned cellulosic ethanol plant and soon-to-be-completed anaerobic digester (AD).

Project Liberty converts corn biomass, baled corncobs, leaves, husk and stalk, into renewable fuel. The plant is now processing its first batches of cellulosic ethanol and will be working toward full capacity around 770 tons of biomass per day to produce cellulosic ethanol at a rate of 20 million gallons per year, later ramping up to 25 million gallons per year. This fuel has been referred to as a “fantasy fuel” reinforced on the front of brochures visitors receive with the words “welcome to fantasy.” This refining fantasy is now a reality, confirmed by all who visit the site.

One of the tour guides, Daron Wilson, Poet-DSM general manager, shared that because it is new technology there is some fine-tuning. “It’s the first of its kind, so there is tweaking,” Wilson said. “Everything is a first, if you’re not willing to change it’s going to wear you out in a hurry, because you need to learn and make changes.”

One of the components of the plant still being tweaked is the AD system with a 1 million gallon digester tank. Wilson said the AD system should be finished soon. Biogas that is not used for Project Liberty is sent to Poet’s adjacent biorefinery for use in the boilers and distillers dried grains (DDGs) dryers or used as fuel for the solid fuel boiler. Excess steam from the cellulosic ethanol facility will also be sent to the starch plant.  The digester and solid fuel boiler is said to produce 2.6 MMBtu per year.

Besides a digester, the cellulosic ethanol facility tour included a walk through the biomass receiving facility where trucks unload bales in six to eight minutes. The receiving facility includes a net wrap remover that rids the bales of their twine and netting before moving them up a conveyor to the grinder. Outside the biomass receiving facility, the pretreatment area can be seen. The pretreatment process conditions the biomass with water, pH treatment and some pressure for conversion, according to Wilson. He said the pressure is used to help break the biomass apart to increase the surface area for the enzymes to react and breakdown the sugars for conversion.

After pretreatment the material goes into the slurry tank to liquefaction where it is agitated and pH treated. Following liquefaction it goes to saccharification where enzymes are added, which is unique to the cellulosic conversion process. Employees refer to the row of nine saccharification tanks as “sac alley.” Visitors also got to see “ferm alley” made up of five fermenters that have a 72-hour fermentation process. C5 and C6 sugars are co-fermented. The facility also has one beer well, a monitoring room and an onsite lab.

Approximately 30,000 tons, or a three-to-four week supply, of biomass bales, both round and square, are stored at Project Liberty’s 22-acre stackyard. Project Liberty will spend approximately $20 million a year purchasing biomass from local farmers. Two contracts are available, either a custom or farmer program. The farmer contract is less hands-on for Poet-DSM employees, allowing the farmers to bale the biomass themselves. Typical contract pricing ranges from $50 to $80 per bone dry ton—deductions can be made based on amount of moisture and ash content in the biomass bale. Farmers remove approximately 1 dry ton or around 25 percent of residue per acre.

Matt Merritt, director of public relations with Poet-DSM, shared how many young farmers in the area have been able to start a solid farming operation by contracting with Project Liberty. “This has really provided a unique opportunity, I think, for a lot of young people to start farming and get involved in agriculture in a way they haven’t been able to before,” Merritt said.

The tour ended with a trip to a farmer’s field to see baling in action. The tour group stumbled across the cornfield stubble to see up close bales being scooped up and then stacked at the field’s edge, where they are stored prior to transportation to the facility.

Future and current efforts at Project Liberty include an alternative use for ash generated during the cellulosic conversion process and a solution to implement onsite enzyme manufacturing.