CVEC fires up gasifier, considers corn cobs

By Timothy Charles Holmseth
In April, Chippewa Valley Ethanol Co. LLLP, a corn-based ethanol producer in Benson, Minn., started up its biomass gasifier, which will burn wood residues to generate power that replaces natural gas.

The gasifier was built by Ames, Iowa-based Frontline BioEnergy LLC. The combustible gas produced in the gasifier will be used for steam generation at the ethanol plant, according to Norman Reese, general manager of Frontline BioEnergy. "Frontline and CVEC have worked together from the start to develop feedstock handling, install the gasifier and integrate the producer gas burner to reach this milestone," he said. Approximately 90 percent of the plant's natural gas usage will be displaced by burning approximately 280 tons of wood waste per day.

In the near future, CVEC and Frontline plan to use corn cobs as an additional biomass feedstock in the gasifier, Reese said. "Long-term plans include increasing the percentage of cobs in the fuel mix, and possibly using stover, prairie grasses, and/or other ag residues," he said. This fall, CVEC will publicly demonstrate the harvesting of 3,500 tons of cobs on at least 5,000 acres. "We will be feeding ground cobs into the gasifier after the harvest in the fall," Reese said.

CVEC General Manager Bill Lee said CVEC chose to focus on corn cobs rather than corn stover for several reasons, one being that cobs produce approximately one-third less ash than stover when burned. Cobs can also be harvested more efficiently, transported more cheaply and stored more easily than corn stover. They are the least-useful part of the corn plant that replenishes the soil after harvest.