Wood Pellet Prowess
The owner of Western Oregon Wood Products discusses his wood pelletizing process with Biomass Magazine, as a prelude to the tour of his Banks, Ore., facility at the upcoming 2009 International Biomass Conference & Expo.
In 1981, 18-year-old Sharron and his brother, Francis, moved from Massachusetts to Oregon. His reasons for moving didn't include an interest in what would eventually become his career. "My dad told me the fishing was great," Sharron says with a chuckle. "And there was nothing tying me to the East Coast."
After the move, he began working at a forest products equipment manufacturing company that was using some equipment manufactured by Western Oregon Wood Products Inc. "In 1985, the owners of WOWP were talking about getting out of the business and selling it," Sharron says. "My brother and I, at 22 and 23, had an interest in buying the business. Since I was working for a related business, I came to know them and had the opportunity to purchase it."
The brothers bought the business in 1986 and, since 1999, Chris Sharron has been the sole owner of the company, and now has three manufacturing facilities; two in Columbia City and Banks, Ore., and another in Dillard, Ore., that he owns jointly with Roseburg Forest Products. WOWP has grown from producing 300 tons of products in its first year, to 320,000 tons per year currently.
The WOWP Columbia City operation has annual capacity of 50,000 tons of finished pellets, which requires 100,000 green tons of material coming into the plant for processing. The company uses waste residuals such as saw dust, planar shavings and wood chips from saw milling operations to produce the 120,000 tons of products it annually manufactures, which includes wood pellets, high-energy fire logs and animal bedding.
Although WOWP still sources from sawmill operations, the lackluster U.S. housing market has prompted them to be on the lookout for other woody biomass sources. "Considering where the sawmill industry is today because of the slump in the housing market the past couple of years, there has been a lot of sawmill closures or curtailments," Sharron says. "So there is a lot less of the residual product available. We've had to start looking-but haven't had to implement it yet-into other sources, or streams of product directly coming out of the woods such as thinnings or slash from logging operations."
Sharron says used pallets and other urban waste stream wood could also be used in the future. "If the sawmill industry doesn't get healthy sometime soon, we will be forced to go in that direction," he says. "And even outside of wood, there are other types of products we could use to make pellet fuel."
The Pelletizing Process
The wood pelletizing process begins when the wood is hauled to the plant site in tractor-trailer loads. Although some tractor-trailers have live bottoms and are self-unloading, most of them aren't self-unloading and require the use of a tipper, Sharron says. "This basically takes the trailer, lifts it up and dumps it."
When the company purchases materials the price is based on weight, not volume. Trailers are weighed on industrial scales upon arrival, and are weighed once again after dumping.
This is done to calculate the net amount of material that was received, so the company only pays for the wood. Samples are taken from each load and are tested for moisture to determine how much it will cost to dry the green load. Often, the wood residuals that are purchased from green saw milling operations contain some of the natural moisture they held as trees, which can be 50 percent or higher. "On a green ton basis, sometimes we have to buy twice as much tonnage of raw material to get the desired amount of finished product," Sharron says. "We also burn a portion of that wood at the facilities to generate heat for the drying process, so every bit of wood that comes in is used."
After the weighing process, front-end loaders are used to scoop up the raw material and feed it into bins then the pelletizing process begins. From the bins the material goes onto a conveyer where it's exposed to large magnets that remove any ferrous metal. The next step is the drying process. "The material enters a rotary drum dryer, which is heated by natural gas, wood or a combination of the two," Sharron says.
Material that exits the dryer is passed over a screen system to pull out chunks of materials that are too large for pelletizing. The larger chucks fall into a hammer mill and are ground into smaller sizes and the "accepts" in the middle portion of the screen are ready to go right to the pellet mills, Sharron says.
The fine portion, which is used to fuel the dryer, is re-circulated to the burner on the dryer and used for in-house fuel. The accepts and hammer-milled material are mixed together before they enter the mills where the pellets are formed.
The pellets are formed using heat and pressure. No additives, binders or glue are used in the process, Sharron tells Biomass Magazine. "They exit the mill hot and rather fragile, until we put them through a cooler," he says. "It's basically just a system to draw ambient air through the pellets to cool them, and allows them to bind up and prepare them to be packaged."
After the cooling process, the pellets are screened to sift out the fine materials such as dust and small pieces of pellets, which are re-circulated through the mills. The finished pellets go through the packaging system where they are bagged, placed on pallets, stretch-wrapped, put into inventory and ready to be sold.
Simple, Yet Challenging
Although the pelletizing process is relatively simple, there are several underlying challenges, Sharron says. "Pelletizing processes in general are the same," he says. "A few small things might be done a little bit differently, but it's essentially the same." The process involves a series of many components, and material handling between each of those components. The challenge involved, according to Sharron, is to keep all of the components working and moving in the right direction every second, every minute and every hour of every day. All of the WOWP plants operate 24 hours, seven days a week. "It's an energy-intensive process that results in a rather low-value product, relative to all of the energy that goes into making pellets, and relative to its weight in the end," Sharron says. "You make some money by producing volume, and this means being in production all the time.
So that's where the challenge is, not unlike any other manufacturing processes, whether you're making widgets or chocolate chip cookies. Work has to be done minute after minute."
The other big challenge that some wood pelletizing companies face is product seasonality. Most of the products that WOWP sells are used in residential heating applications. "Although we hope to see them develop, our markets are not yet commercial or industrial applications for process steam or power, where every day a customer needs a certain amount of fuel," Sharron says. "Right now we're coming out of our season, and we'll have a long dry spell until next September when that market starts calling for our
To maintain the company's sources of raw material, keep employees working, and build enough product and inventory to meet the demand in the next season, facilities must run year-round, even in the spring and summer. "Cash flow becomes an issue during those times of year, because we can't call up sawmills and say we're done for now, but will call again next September," Sharron points out. "They'll find somebody else who will take the stuff year-round, so we have to be consistent-and we can't lay our people off and expect them to come back the next season."
Furthermore, competition to obtain raw materials can be stiff. "Finding enough raw material to work with every day, with all the sawmill curtailments and closures-it has always been a challenge," Sharron says. "These markets have always been kind of up and down, and there are competitors for these residuals-not just pellet plants, but particle board plants, pulp mills, nurseries, animal and livestock raising facilities, and horse barns and stalls, which use that type of material. That's always been a challenge-meeting daily and seasonal needs."
Not surprisingly, demand fluctuates year to year and influences how much product a pellet producer manufactures. "The residential pellet market has been around since the mid-80s," Sharron says. "It goes through cycles and has not experienced very steady growth over the past 20-plus years."
When fossil fuel costs rise, people are driven to look for alternative fuels, such as pellets, to heat their homes. During those times, the demand for wood fuel rises. "The next year or the year after that, fossil fuel costs may level out and there isn't a lot of interest anymore, so things will slow down," Sharron says. "If someone is looking at getting into this business, they need to consider this." Sharron remembers when they had a pellet shortage in the western U.S. because some producers expanded their markets and shipped a lot of product to the Midwest and the East Coast. Although the market quickly corrected itself, the next season, fuel was kept closer to home. In the meantime, many new pellet producers came on line basing their decisions on the pellet shortage headlines. That in turn created a surplus. "It's frustrating, because the shortage wasn't as big of a problem as it was made out to be," he says. "There are cycles that suggest that people need do their homework and make sure there is a market, or they will really suffer with those cash flows and trying to penetrate the market."
Tour of the Banks Facility
Attendees of the 2009 International Biomass Conference & Expo in Portland, Ore., April 28-30, will have the opportunity to get a first-hand look at WOWP's pellet plant in Banks.
The plant is near a sawmill that is currently not in operation during the off-season. "Attendees will be able to see a rather unique design-the way this plant is so compact-and they will get a good feel for what the whole process entails from the drying operation right through to the pelletizing operation." Sharron says.
Anna Austin is a Biomass Magazine staff writer. Reach her at firstname.lastname@example.org or (701) 738-4968.