North Central Area’s Biomass Reboot
In January 1982, the same year that a small welding and manufacturing company in Bark River in Michigan’s Upper Peninsula was officially incorporated, it built and installed a biomass heating system at the nearby North Central Area’s high school building in Powers, Michigan. The area surrounding the community of Powers is rich in timber, and the school, hoping to capitalize on abundant streams of waste wood, made the decision to heat its facility with biomass. The project was the first of its kind for Messersmith Manufacturing Inc., and it provided the young company with a successful case study it could point to, right in its own backyard.
The system was built in parallel to the existing natural gas system, tucked neatly into the basement of the school. When the facility was built, the school received fuel deliveries in much smaller quantities, typically by small, dump-truck sized loads. At the time, the on-site storage capabilities were well suited for the existing waste wood collection and delivery infrastructure. This didn’t last long, however, and eventually, the fuel delivery infrastructure completely outgrew the fuel receiving operation.
Brett Harter, head of maintenance and transportation at North Central Area School, joined the district staff in time to have operated the original system. “It would take anywhere from an hour and a half to three hours to unload a truck, because the biomass would go into a hopper and up through a conveyor, and on to another conveyor in the building that would spread it out,” he says.
The system became finicky in its old age, Harter says. “It had been revamped a bit in 1994, but the chip delivery system was completely worn out, the augers and things like that.” Back then, the challenge for Harter was that toward the end of its useful life, the chip handling system required daily monitoring. “I was there seven days a week,” Harter says. “I’d have to go there every day. If I let it go too long, and there was a belt off or something, you’d wind up with one heck of a mess.” Specifically, Harter pointed to a metering bin that, when full, had a flapper mechanism that would turn off the conveyors that fed it with new chips. On more than one occasion, the flapper mechanism failed, and an entire truckload of chips would overwhelm the metering bin, filling the room with chips. For Harter, this meant the better part of a morning shoveling chips by hand.
The team at Messersmith, many of them just kids when the original system was installed, recognized that the school’s boiler and chip handling system was in a need of an overhaul. “The problem really was that it would take the better part of day to get the fuel from where it was delivered outside into the storage area,” says Jeremy Mortl, president at Messersmith. “There wasn’t a good place to park a truck to make a fuel delivery that made sense for where it was ultimately stored. That was a big struggle.”
A number of other capital projects, including new parking lots and some new buses, led the district to launch a bond initiative and the timing seemed right to capitalize an overhaul of the biomass heating system. “They called us up,” Mortl says. “The district just doesn’t have time to maintain a boiler or service any issues that may come up. They needed something that had minimal maintenance. Their other desire was to have more fuel storage capabilities. They wanted an easier solution to get their fuels into their fuel storage area.”
The first challenge the Messersmith team had to confront was positioning a new fuel handling facility in a way that would allow a truck to get in, unload, and get out with the greatest ease. The school building sits on a relatively small footprint, and both Messersmith and the district knew that gobbling up even more already limited parking space would not be popular. “We had to come up with the best solution for a building layout so that they could get truck and trailer in there, get it turned around, and empty fuel into the bin,” Mortl says. A local engineering firm was hired, and together, the companies worked up a plan for a covered building that would not only receive fuel deliveries, but also hold a combustion unit, a boiler and the associated piping and control systems.
This collaboration led to an initial design concept that Mortl describes as “pretty close” to what was eventually built. “The one change the district made to the initial design was to have more fuel storage capability than what we had originally drawn up,” he says. “They can take more than one full truckload of fuel now. Plus, it makes it nice for them in the summer time. When there is no fuel in that bin, they can keep a couple of pieces of equipment in there.”
The final design included a 93-foot by 24-foot building, and with over 1,000 square feet of that space dedicated to fuel storage, over 50 tons of wood chips can be held on-site, enough to feed the boiler for nearly three weeks in the coldest days of winter. Also included in the project was a traveling auger design that Messersmith invented. “There is an auger that travels along a beam in a carriage system,” Mortl says. “That carriage will travel along the 60-foot length of the beam, and the auger will move material onto the belt conveying system. There are carbide teeth built into that auger system so that if frozen or compacted fuel comes into the building, those carbide teeth will chew it up, break it apart, and move it onto the belt conveying system.”
Tight Construction Window
A unique challenge confronting the design and construction team was the limited time frame that comes with doing work for schools. Groundbreaking wasn’t held until the day after school let out for the summer. Once the property was vacated, building began in earnest.
The concrete work was completed first. A three-and-a-half-inch pad, with larger footings to support the weight of the combustion unit and boiler, was engineered and poured. Once that was complete, a crane set in the Messersmith combustion unit, and atop that, a 2.5 million MMBtu Hurst boiler. The heat output closely matches the district’s old system, but Mortl highlights the dramatically increased efficiencies in the new boiler. “The old boiler worked just fine,” he says. “But it was 30 years old.”
One advantage that Messersmith uses to make the most of short construction timeframes is its in-house fabrication capabilities. While the demolition, excavation and concrete work were being done at the school, Messersmith’s welders were building the combustion unit, the fuel handling system and all of the ladders and catwalks for the facility. “The same crew of people who manufacture the equipment are the same ones who go and do the installation on it as well,” Mortl says. “This is one of the more unique things we do. We are a turnkey solution in that way.”
Once the main components were in place, the general contractor began erecting the building around the new system. Work progressed throughout the summer, and the system was still being buttoned up when the late summer temperatures finally gave way to early fall, and the oncoming heating season. “We fired up the system Nov. 14,” Harter says. “They were still just finishing up the electrical inside the building.”
For Harter, the transition to the new system couldn’t have been easier. The control systems are virtually the same, and there is no longer day-to-day worry over the fuel handling system. For him, the biggest challenge has been letting go of his old habits. “If I go by there on a weekend, I’ll stop by,” he says. “But I don’t have to. On Friday night, I’ll make sure the ash bins are empty, and I won't see the system again until Monday morning.”
The extent of Harter’s weekly routine, which was once characterized by time-consuming repairs, is now emptying ash bins and sweeping, he adds. “This new system, it’s just a world of difference.”
Author: Tim Portz
Executive Editor, Biomass Magazine