Guess What's Powering Mizzou?

CAFNR is working with the campus' power plant to determine if using discarded corn cobs mixed with coal is viable.

Guess what's powering Mizzou? (WMV)

Corn cobs were blended with the coal to observe handling, mixing, conveying and combustion. Photo by Greg Horstmeier

CAFNR is working with the campus' power plant to determine if using discarded corn cobs mixed with coal is a viable method to reduce fuel costs while helping to keep the pollution in the skies to a minimum.

The power plant, part of the MU Campus Facilities - Energy Management department, burns up to 175,000 tons of washed and screened bituminous coal a year. Most of that coal is mined in central Illinois.

In initial tests, 2 to 3 percent of cobs by mass were blended with the coal to observe handling, mixing, conveying and combustion. The cobs are from a 16-ton load shipped from Nebraska.

"The tests went well. We didn't have any problems at all," said Gregg Coffin, plant superintendent.

Additional tests may use up to 20 percent cobs in the plant's overhead chain gate stoker boilers and spreader stoker boilers.

"I'd like to shoot toward 10 percent, but realistically, I'd be pleased with 3 to 5 percent of our consumption by mass," he said.

"Five percent of our annual fuel consumption would use corn cobs from over 16,000 acres of harvested Missouri cropland," said Coffin.

"The heat value of the cobs runs about 75 percent of the coal we burn. Combustibility is not an issue." The challenge is in the handling and the mixing of the light corn cobs with coal.

"Our goal is to explore biomass fuels to reduce emissions, support local agricultural businesses, and to possibly lower our fuel costs," Coffin said.

"If we can be revenue neutral, we get great benefit from reduced emissions and establish a renewable energy product to help local agriculture," he said.

Coal now costs $42 a ton, but is expected to reach $48 a ton in March.

"We're equating at future prices that corn cobs could be valued at $35 to $36 a ton, assuming we look at only the heating value of the fuel, not any operational costs," he said. "Corn cobs are not likely to escalate in cost as fast as other fuels."

Leon Schumacher, agricultural systems management professor, said using cobs as an alternative heating fuel has great potential for Missouri farmers. A 160-bushel-per-acre yield of corn would produce about 1,200 pounds of cobs, or a return of $9 to $15 per acre on a biomass, which is otherwise left unused.

Combines would have to be modified to include an extra tank and blower to collect the cobs, an investment of about $10,000, he said.

MU faculty and staff are involved in field demonstrations this fall to recover cobs from Missouri corn fields. These tests, in addition to the burn tests at the MU power plant, with help the university learn of harvest costs and time and additional resources needed to handle the cobs.

Schumacher said cobs have a higher density than other alternative biofuels crops such a switchgrass or hay, giving cobs an advantage as a fuel source. Harvesting cobs also would not compete with corn acres grown for the emerging ethanol industry, which uses only corn kernels to produce fuel.