By Lori Ehde
The long-awaited thermal oxidizer will be fired up at Luverne's Agri-Energy ethanol plant on Oct. 23.
It's the $1.5-million solution to the plant's odor problem that has prompted community complaints since it began operating in 1998.
The equipment was ordered in January and arrived for installation in July. It's a major project that required two additions, one for the electrical panel and one to house the boiler.
The oxidizer was scheduled to start operating by late summer, but inspectors required additional equipment that delayed startup.
According to Plant Manager Rick Serie, the Agri-Energy plant will shut down Oct. 22 for usual fall maintenance, so the oxidizer will be installed at that time.
It's also well-timed with a recent settlement with the Minnesota Pollution Control Agency and the EPA.
MPCA settles with 12 ethanol plants
Agri-Energy Ethanol Plant is one of 12 plants statewide to reach an agreement last week with state and federal regulators on plant emissions and permitting.
A consent decree filed in U.S. District Court, St. Paul, Wednesday, addresses all concerns of the MPCA and the EPA and will result in cleaner ethanol production.
"The Minnesota plants have led the way for the entire ethanol industry by proactively working with the agencies to develop new control solutions to improve the environment," said Bill Lee, co-spokesman for 11 of the 12 plants covered by the agreement.
"By investing in additional control measures, the ethanol industry will reduce emissions well below the requirements in the Clean Air Act. The agreement calls for the implementation of the best available control technologies for all significant plant emissions."
Luverne's thermal oxidizer and additional controls will meet requirements spelled out in the agreement, according to Serie.
"We make a fuel that's good for the environment, so I don't want to be known as a polluter," he said.
He clarified that the settlement doesn't assume blame. "They never stated we were out of compliance, they just assumed we were," he said. "It would have cost more to fight it than it would to settle."
On the positive side, Serie said the process moved quickly.
"Everyone is extremely pleased with the cooperative effort.
"This settlement was arrived at in record time. Most cases like this take years to resolve. We settled 12 plants in five months."
How does it work?
In the thermal oxidation process, odor is eliminated by venting plant emissions into the oxidizer and destroying them with heat.
Meanwhile, the plant will capture heat off that process in a recovery steam generator to create steam for the ethanol production process.
Another advantage to the oxidation process is that it will allow the plant to increase production while remaining in compliance with the MPCA's emissions standards.
In fact, Serie said, the plant decided to pay $268,000 more for a larger model that will allow the plant to double its production in the future.
While the oxidation process requires a hefty up-front investment, Serie said it may pay for itself in five years.
Gained efficiencies of the boiler, costs cut by not using the scrubber and the freedom to expand production all make the oxidizer a worthwhile investment, Serie said.
The 175-foot stack will remain, but the steam plume coming out of the stack will be all but eliminated.
"Cold air condensing hot air makes steam, so there may be a plume in the wintertime, but there won't be any emissions," Serie said.
The existing boiler will be moved into a support position to be used as backup if needed.
Agri-Energy started production in 1998. It now employs 29 people full-time with an annual payroll of more than $1 million.
It processes seven million bushels of corn per year and produces more than 20 million gallons of ethanol annually.