With conventional sources of heating (gas, oil, electricity) becoming less reliable and more expensive, a lot of people are harking back to alternative ways to heat their homes and other spaces. In areas where supplies are fairly abundant, wood, that oldest of heating fuels, is making a strong comeback.
But it’s wood with a relatively new wrinkle—it’s in clean pellets. And pellets as home-heating fuel are catching on fast. According to the Pellet Fuels Institute, there are now more than a million pellet stoves and fireplace inserts used in homes in the U.S. and Canada; supplied by nearly 100 pellet manufacturing mills across North America.
One of them is M&M Wood Pellets. About two years ago, Matt Young and his family began producing wood pellets in Laclede County, Mo.
“We were operating a hunting preserve and a horse arena, but with the economy so stagnant, we also wanted something that wasn’t tied so closely to recreation,” said Young. “We had an ample supply of sawdust at Independent Stave Company in nearby Lebanon, so we decided to get into the pellet business.
“One of our biggest problems early on was that there isn’t much information on how to set up or operate a pellet mill,” Young added. “We sort of had to pick our way into the business.”
Lacking much guidance on setting up a pellet mill, Young decided to lay the facility out pretty much as he might do with a feed pelleting operation, in a “straight-line” production plant: raw sawdust in one end, bagged pellets out the other end.
“It’s exactly like a feed pelleting system; in fact, some of our equipment came from a feed mill,” he said. “We first run the sawdust through a hammer mill, and then it goes to the pelleting machine. From there, the pellets are cooled and then bagged. We have operated virtually 7 days a week since we began and barely keep up with the demand. This fall, we installed a new pellet mill that boosts our output to 2 tons per hour.”
M & M wood pellets sell through MFA and Meek’s, a regional lumber and hardware chain. The kiln-dried sawdust, at 8 percent or 9 percent moisture content, is a by-product of Independent Stave’s wine and whiskey barrel manufacture.
“That saves us one step in pellet making,” said Young. “If we were using green sawdust, we’d need to dry it before we ran it through the pelleting process. As it is, the sawdust from Independent is too dry to feed through our system properly. We have to reconstitute it to about 13 percent moisture with a water spray, but the heat of compression in the pelleting machine dries that moisture out.”
Young produces pellets by pressing the pulverized sawdust through a die at very high pressure, which generates high temperatures. This makes a pellet that is ¼ inch in diameter by about ½ inch long. This uniform geometry and small size lend pellets to automated feeding by auger, conveyor or air systems into the fireboxes of stoves, furnaces and boilers.
Wood pellets are very dense and low moisture—about 10 percent. The average energy content of pellets such as M&M produces is about 7,500 Btu per pound.
“We make a high quality pellet with high heat output and low ash content,” said Young. “They are pure oak hardwood, with no bark and no sapwood. And we don’t add any fillers or binders; the heat of compression melts the lignin in the wood so the pellet holds together.”
And the burning of wood pellets emits less nitrous oxide and sulfuric acid than most fossil fuels.
“In many ways, this has been a learning experience as we go along,” said Young. “But we’re steadily improving the process and the product, and we have plenty of raw material to expand quite a bit more.”