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Columbia Missourian

MU power plant replaces old boiler with biomass boiler

By Mina Mineva
April 16, 2009 | 12:01 a.m. CDT

COLUMBIA — As one of the six boilers at the MU power plant nears the end of its life, the boiler known as No. 11 — no, the numbers really don't add up — will be replaced with a biomass boiler, which will mainly use waste wood chips and other sources of biomass such as corn stover.

The replacement and conversion to the biomass boiler from the current fluidized-bed boiler will cost an estimated $62 million. The funding is expected to come from bonds, but the university says it would prefer to use stimulus money should it become available.

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"We have to replace the boiler," said Gary Ward, assistant vice chancellor of facilities. "We have no other choice."

Ward said the university has known for more than 10 years it would need to replace the boiler. Since its 1987 installation, it has not worked properly, nor has it had the capacity, reliability or efficiency the university expected, Ward said.

A 1996 study recommended it be replaced by 2008.

“By the time we decided to replace the boiler, MU had demonstrated that biomass fuels could be used to provide energy for MU, and technologies had improved for the use of biomass, so it made sense to install a 100 percent biomass-fueled boiler,” Ward said.

Since 1995, the MU plant has been using various forms of biomass fuel, such as wood chips, chipped tires, corn cobs and switch grass. But the plant was limited to replacing 5 percent to 10 percent of its coal use with these products because none of the boilers were specialized in biomass only, Ward said.

The new boiler will mainly burn wood waste chips, along with other biomass fuels. A future goal for the plant is to use other biomass fuels such as switch grass and paper pellets as fuel, Ward said.

“The new boiler will be environmentally superior in all ways,” Ward said. “This past couple of years, we have burned 7,000 tons of waste wood chips, and we have reduced plant emissions by 4 percent.”

Burning wood chips saved the university $50,000, and it lowered greenhouse gas emissions by more than 7,000 tons, he said.

"This new boiler is a fantastic opportunity to move away from coal fuel and into a more sustained method of producing energy," said Patrick Margherio, president of Sustain Mizzou.

About four years ago, Sustain Mizzou, a student-run organization providing local action and public education about the environment, joined forces with the power plant to help pass the tire-derived fuel legislation.

By using tire-derived fuel, the power plant saves MU up to $300,000 annually and produces emissions with less sulfur than coal, Ward said.

"It is a common misconception that burning tires causes a lot of emissions," Margherio said. "If it's a regular tire fire, it is not hot enough to burn the carbon and sulfur emissions. A power plant, though, is hot enough to burn the carbon and sulfur.  Tire fuel is a lot more sustainable than other types of fuel like coal."

MU is one of the few universities that uses tire-derived fuel full time, Ward said.

He also said the new boiler, which will be called BFB 1, will not cost the university more money to maintain and operate than No. 11, but it will be a lot more environmentally friendly.

In addition to helping the environment, the boiler will allow MU faculty to be more versatile in their research. They will be able to test different types of biomass fuel under a much wider range of operating conditions, said Leon Schumacher, an MU agricultural professor. The current boilers limit the experiments by moisture content and volume, he said.

The researchers also plan to explore the idea of using air to push the biomass products through the system and into the combustion chamber of the boiler.

The new boiler will also help enhance recycling efforts by possibly using some  campus dining waste products, such as paper plates and plastic utensils, as fuel, Schumacher said.

For right now, consultants are working on the design of the new boiler and the plans for storing the biomass it will burn. The fuel storage system currently holding the plant’s biomass isn't big enough for the university's future plans, Ward said.

The designers have also looked at other environmentally-conscious plants, such as the St. Paul District Energy Plant, which is primarily fueled by clean urban wood waste, according to the plant’s Web site.

The replacement work is projected to start next year, and the new boiler is expected to be up and running by 2012.

"We have got to be more creative with today's environment and waste stream," Schumacher said. "By putting this boiler into place, we will be able to investigate more opportunities to improve our environment."