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Sawmills Add Drying As Industry Changes

Dehumidificaion - Technology from Nyle Dry Kilns Helps Sawmills Add Drying Operations

Date Posted: 3/1/2000

Throughout the first three-quarters of the 20th century,relatively few milling businesses kiln dried the lumber they produced. This wasespecially true of smaller firms, notes Don Lewis, president of Nyle Dry KilnSystems.

As the 21st century dawns, however, thepractice is changing, according to Don. New technology, especially in the formof dehumidification kilns, allows even small producers without extensiveexpertise to successfully dry the lumber they mill. Driven by the need tomaximize value from the fiber they buy, an increasing number of sawmills isinstalling dry kilns as part of their operations, making lumber drying the rulein today’s mill rather than the exception it once was.

Partof the new emphasis on drying comes as a result of changes in the forestproducts industry. The lumber industry is going in a different direction thanthe rest of the North American economy, Don noted. While most industries areconsolidating, the forest products industry is breaking up into smaller pieces."There are a lot of small guys in the industry who are starting up andbeing successful," he said. "And with today’s dry kiln technology,they can all dry lumber, so you’re seeing mills at all levels — even down tothe portables — installing kilns."

Dehumidification kiln technology is asignificant part of the reason that more mills are willing and able to drylumber, Don said. In the not too distant past, only large companies that couldpay for the services of a specialist in drying could hope to successfully drymost woods. The large, old steam kilns that used to be the standard for dryingrequired a "witch doctor" with years of experience to run them and getgood results. Now, however, even someone who has never seen a kiln can operate adehumidification unit successfully with only a small amount of training,according to Don.

Another reason that small companies are ableto use dehumidification units is because they cost several times less to installand run than older technologies. The reduced cost of owning and operating adehumidification kiln combined with the increased value for dried lumber putdrying technology within the financial reach of virtually any mill, said Don.

Heat pump systems are at the heart ofdehumidification kilns. As Don explained the technology, air is heated to abeginning point of about 80 degrees and circulated by fans over the greenlumber. Water contained in the wood evaporates. The hot, moist air is then drawnover a cold refrigeration coil that cools the air to about 60 degrees. As theair cools, the moisture condenses back into liquid form and is drained off.

Thisis a key to the cost effectiveness of dehumidification technology. Inconventional kilns, the hot moist air is vented, so heat is lost. In adehumidification kiln, heat that is removed is recycled and is used to warm theair again. The process is so energy efficient that air leaving the dehumidifieris even hotter than it was when it entered; the air temperature inside the kilnrises as the process continues. Internal temperatures can reach 160 degrees.

There’s not much question that mills, largeor small, can profit from drying wood. For example, Don compared freshly sawnred oak, which might sell for 80 cents per board foot, to dried lumber, whichsells for about $2.50 per board foot. For a cost of about 3.3 cents per boardfoot to dry the lumber, a mill can add value of $1.66 per board foot — asignificant increase in profitability.

Kilns also help to provide added stability toa mill’s operations. With drying capability, a mill has a good deal moreflexibility in its marketing program than mills that sell only green lumber.

Cliff Clune, president and general manger ofClune Lumber in Otego, New York points to the expansion of markets as animportant benefit his company gained from kiln drying. "It’s opened upmarkets all over the world to us," he said. "We’re able to sell toend users anywhere. Today we export about 50% of our product. That would not bepossible without our drying capacity."

Drying also impacts transportation-relatedcosts significantly. Eight thousand feet of freshly cut red oak weighs about43,500 pounds, Don noted. The same 8,000 feet of lumber, dried to a moisturecontent of 6% to 8%, weighs only 28,000 pounds. Weight is an important componentof fuel use, load space, and wear and tear on roads, and such reductions areeconomically beneficial.

Clune Lumber is a hardwood manufacturer,sawing mostly hard maple and a smaller volume of red leaf maple and cherry intohigh grade, random width and random length lumber.

Fordrying technology, Clune Lumber relies on Nyle dehumidification kilns. Thecompany has three 40,000 chambers for total capacity of 120,000 board feet.Clune Lumber has been kiln drying for about 10 years.

Drying dramatically increased his company’sprofits, according to Cliff. When the company manufactured green lumber, it hadto be shipped elsewhere to be dried, restricting potential markets and profits."It’s a value added to the lumber that greatly expands our options aswell as our profitability," said Cliff. "It’s given us much moreflexibility than we had before in managing our operation well."

Clune Lumber chose dehumidification kilns fortwo major reasons. First, the systems cost considerably less to build and alsocost less to operate than conventional kilns, according to Cliff. Second, thehardwoods used by his company are best dried with dehumidification technology."It keeps the lumber brighter and we see less degrade than with other kindsof drying," said Cliff.

Brighter lumber and reduced degrade areextremely important to a company with a global market, Cliff noted. Of course,degrade reduces profitability because whatever material must be removed from afinished piece of wood to bring it back up to standard represents money that wasspent on buying the raw material and processing it; material that must beremoved because of degrade now is nothing more than waste. Quality is criticalbecause of the high cost of shipping to overseas markets; the cost to the millof a rejected board is much higher, and its tarnished reputation as a suppliermay prove even more costly.

Forcompanies thinking of adding drying operations, Cliff advised doing it instages. Cash flow may be a problem when a mill goes from sawing green lumber todrying, he admitted. Green lumber is shipped directly to customers while drylumber may be marketed through a longer chain to customers around the world, soit takes longer to get paid. At Clune Lumber, Cliff gradually moved the companyinto drying. The company dried only about 15% of its production in the earlyyears, building it up to the point where now virtually everything is dried."Unless you’ve won the lottery, I think it’s best to work into dryinggradually," said Cliff. "It’s easier on the cash flow, and it givesyou a chance to learn how to dry as you go along."

Cliff also recommended a new product thatClune Lumber recently began to use — Breeze Dried Stickers. Sticker ‘shadow’or discoloration is a problem with woods that must be dried to a bright finish,he noted. However, the specially designed Breeze Dried Stickers have virtuallyeliminated the problem, he said. "I’d recommend their producthighly."

Many mill owners may view dehumidificationkilns as a solution for small operations. But M.L. Wilkins & Son, a wellknown dimension mill in Fredericton, New Brunswick, has demonstrated that millsof all sizes can efficiently use dehumidification technology.

M.L. Wilkins & Son is a modern mill. Ithas a Denis Comact fully optimized curve saw system that produces more than 40million board feet of dimension spruce and fir annually; about 84% of the mill’sannual production is spruce and the remaining 16% is fir.

M.L. Wilkins & Son is equipped with bothconventional steam kiln systems and 55,000-foot Nyle dehumidification kilns. Thecompany added Nyle technology after running the steam kilns for several years,said general manager Brent Wilkins. In a high production mill such as hiscompany, drying operations must be carried out continually, he explained. Yet,the boilers require periodic maintenance and repair. "I wanted to be ableto shut down my steam system and continue to dry," said Brent. "Withthe dehumidification kilns, I can do that."

The Nyle systems gave the company anotheradvantage, he said. The dehumidification kilns result in a "superiorproduct," he said. The lumber dresses out better and there is less degrade.

Thecompany operates both types of kilns throughout most of the year. The Nyledehumidification kilns are devoted to drying most of the fir because it requiresmore gentle handling than spruce, which is dried in the steam kilns.

Whether large or small, mills will have tohave drying operations in the future as the market is shying away from greenlumber. Building codes are requiring dried lumber, Brent noted, and shippingdried lumber is much more economical because it weighs significantly less.

Randy Cutshaw, president of Allied WoodProducts in Winchester, Va., has experience in drying both from the millperspective and as an end user. Allied runs a circle sawmill with a band resawand produces 20-25,000 board feet of grade lumber per day. Most of the lumber issawn from red oak. Allied dries the lumber and then saws, molds, turns, orotherwise processes it in Allied’s operations for manufacturing stairways andstair parts.

Like M. L. Wilkins & Son, Allied WoodProducts has both conventional and dehumidification kilns. Allied has threeconventional kilns with a capacity of 100,000 board feet and a Nyledehumidification kiln and two more Nyle kilns on the way. Capacity of the Nylekilns will be 125,000 board feet.

Allied Wood Products was established in themid-60s. The first steam kiln was installed in the early 1970s, and the othershave been added periodically since then. The company experimented withdehumidification technology when it was first introduced but abandoned it; atthe time, dehumidification kilns were still being pioneered and the technologyhad not been fine tuned, Randy said.

The changing timber resource and theincreasing demands of the marketplace require companies like his to stay on topof current technology, Randy said. Dehumidification technology has provensuccessful and gained wider acceptance. Randy looked at it again and wasimpressed by what he found. The kilns could produce dry wood without cupping orother stressing. Also, the wood "goes in bright and comes out bright,"he said.

The results that Allied has achieved with theNyle kilns have met his expectations, Randy said. When asked what advice hewould give to a mill that wants to add drying operations, Randy’s answer wasclear. "I would tell them to go with dehumidification. It’s an easiertechnology to handle in the drying process, and you get a better product out ofit. It is easily the best way to go for someone who hasn’t dried before,especially if they are going to be drying hardwoods."

As the forest products industry has reshapeditself in recent years, it has become clear that drying is a technology thatprogressive companies will want to have. The experience of Allied Wood Products,M.L. Wilkins & Son, and Clune Lumber demonstrates that dehumidificationtechnologies for drying wood are often the best choice, especially for dryingsensitive species where value is lost if the wood is stressed.

As Don Lewis of Nyle Dry Kiln Systems pointed out, the mostefficient businesses are those thriving in the forest products industry oftoday, and many of them — both large and small — are enhancing theirefficiency by drying lumber with dehumidification technology. 


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