United Ethanol to install anaerobic digester

By Holly Jessen | October 14, 2010
Posted Oct. 27, 2010

A $6.75 million project to install an anaerobic digester at a 50 MMgy ethanol plant in Milton, Wis., will begin in a few weeks. United Ethanol LLC will complete the project with the help of $2.25 million in state energy program funds. "It's a way to extract a little more value out of our inputs, the corn, and make the plant greener and more energy efficient," said Alan Jentz, United Cooperative and United Ethanol vice president of grain operations and risk management.

On Oct. 21, Wisconsin Gov. Jim Doyle announced $2.95 million in funding for three southern Wisconsin companies, including United Ethanol. The money comes from Wisconsin's economic development tax credits and energy program, which is funded through the American Recovery and Reinvestment Act. The other two projects were $250,000 in tax credits for Standard Process Inc., a whole food supplements company, and $450,000 in energy program funds for Idle Free Systems Inc., which sells battery-powered, idle-elimination systems for over-the-road trucks.

In total, more than $55 million in state energy funds from the recovery act are being used in Wisconsin to help manufacturers with energy efficiency and renewable energy projects. According to the governor's office, Wisconsin is the only state using 100 percent of these funds for these types of projects. In August, Ace Ethanol LLC received $595,000 in funding from the same program for heat exchange equipment.

United Ethanol's anaerobic digester will utilize a portion of the plant's thin stillage to create methane, which will help reduce natural gas use at the plant by up to 25 percent. The project will have an estimated four-year payback, Jentz said.

The project has multiple benefits, including reducing the plant's carbon footprint. The anaerobic digester is also expected to reduce the number of fermentation solids that have to be recycled, reduce fermentation inhibitors, reduce evaporator bottlenecks and eliminate syrup load-out, Jentz said.

Technology provider Eisenmann Corp. will install the digester. The project should take about a year to complete. "We hope to get that under way here in the next few weeks, so hopefully it will be online by this time next year," he said.

Anaerobic digestion isn't the only technology upgrade project United Ethanol has on its plate. David Cramer, president and CEO, mentioned three projects in the company's August newsletter. The company is working to tie in the CO2 scrubber stack and process vent gas scrubber stack into the regenerative thermal oxidizer for odor control. In addition, it has a license agreement with GreenShift Corp. to use its corn oil extraction technology. United Ethanol has also contracted with Arisdyne Systems Inc. to install controlled flow cavitation, a patented process to reduce particle size, disrupt cell structures and disperse agglomerates for increased ethanol yield.