Collins Hardwoods Looks at Kiln Innovations

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Working with BOLDesigns, Collins Hardwood’s West Virginia Plant is looking at unique drying approach developed by timber industry consultant, Dennis Clay.


Being on the forefront of innovation means being in the right place at the right time with the right idea. Working with BOLDesigns, Collins Hardwoods in West Virginia is looking at taking a step into the next generation of kiln drying hardwoods, using a unique technique developed by consultant Dennis Clay.

Andy Roberts is the plant manager at the Collins Hardwoods plant in Richwood, West Virginia. He has a long history in the lumber industry.

“I’ve been in the lumber business for almost 40 years,” he said. “Most of my career has been in the southern pine part of the industry. I came to work with Collins in November of 2012.”

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Andy started working in the lumber industry right out of high school, when he went to work for his uncle who already was in the business. He worked at several mills until three years ago, when he was hired by Collins Hardwood.

One thing Andy liked about Collins Hardwoods is that it’s family owned and has been around for a long time.

“The company has been around since 1855,” he said. “It started in Pennsylvania and then moved out west. We now own two facilities on the east coast, one in Kane, Pennsylvania and this one in Richwood, West Virginia.” There also are five facilities in California and Oregon.

Andy said there are some significant differences between working in the southern pine industry and working with hardwoods.

“Hardwoods are a whole different ball game,” he said. “Logs are expensive and with the value of the products produced, there is little room for errors that impact quality and grade. We have to get the maximum value out of each log.”

That means drying schedules and kiln time are crucial in the management of hardwood lumber.

“When I came here, I was used to high temperatures and drying schedules of 18 to 24 hours,” Andy said. “Up here, we measure drying schedules in days, not hours; we work in times such as 14 days up to 30 days. “So it’s very different.”

The purpose of the long drying times, Andy said, is to prevent the development of kiln defects in the finished lumber.

“That includes checking, and honeycomb on the ends, and crooked lumber,” he said. “That comes from bringing the moisture out of the lumber too quickly. You can’t do that in hardwoods.”

He did note that kiln drying times vary by species.

“We can dry whitewoods more like a pine,” he said. “These kilns are not high temp like the pine kilns were, but you can push schedules more with the poplars and maples than you can with red oak. Red oak is a slow drying process in order to protect the lumber.”

Until this spring, Collins Hardwoods had ten conventional kilns. This year, however, Andy needed to add kiln capacity at the West Virginia plant, so he went to BOLDesigns for help installing two refurbished kilns tailored to his needs for drying hardwoods.

“Our employees have embraced new ideas that have allowed us to increase production in the sawmill to where we had to have more kiln capacity,” he said. “We bought two used kilns and contracted with BOLDesigns to install them. BOLDesigns modified the kilns to turn 60,000 board foot kilns into 80,000 board foot kilns by raising the height of them.” BOLDesigns did all the construction, as well as the programming of the kilns. The Collins Companies’ engineers Todd Laitinen and Bob Jackson, along with supervisors Roy Sandy and Jimmy Thompson, worked with the BOLDesigns team to get the project completed.

Andy pointed out that the capacity of the kilns varies according to the product being dried.

“On certain species and thicknesses, the capacity may go up over 80,000 board feet,” he said. “On others, it may be down in the 70,000 board foot range.”

The number of sticks in the lumber is what makes the difference in how much the kiln holds, Andy said.

“With thicker lumber, you have fewer sticks for the full stack of lumber in the kiln,” he said. “If you’re drying 4/4 boards and have a ¾-inch stick between the boards, you have more stick layers between your lumber than you do with thicker boards. On the thicker boards you have fewer sticks, so you can put more volume of usable lumber in the kiln.”

The length of the lumber also affects what the kiln can hold.

“If you have a 32-foot wide kiln, you have to have the correct length mix to fill the whole 32 feet,” he said. “We get two 16-foot stacks in the kiln side by side, but some combinations of package lengths do not add up to 32 feet, and it’s possible to come up 2 feet or 4 feet short just to get the kilns loaded and back up and running.”

Andy turned to BOLDesigns for help because of the company’s history of innovation in the lumber industry.

“We basically rebuilt both kilns,” said BOLDesigns company president Brett Bollinger. “We totally redid the heat controls and new everything.”

One thing that’s innovative about the kilns, Brett said, is the way BOLDesigns builds the walls.

“There are many variables in lumber, including where it came from, what part of the tree it was cut from, and how long it has been on the yard,” Brett said. “What we try to do is take out all the mechanical variables. We try to make our kilns equal throughout. In other words, if you cut our kiln four ways, all four quarters would be the same in terms of heat and air.”

Brett said BOLDesigns kilns have smooth walls to prevent any structure from disturbing the airflow.

“Our kilns have a slick interior, which nobody else uses,” he said. “It’s just like putting ductwork in your house. You don’t turn the flanges to the inside; you have the inside smooth so the air will flow smoothly.”

BOLDesigns kilns also utilize wall-to-wall heating coils with no gaps to keep heat distribution as even as possible, and minimize the possibility of wet pockets or uneven drying.

“We also stand our heating coils upright, and the heat is all center pipe from the original source,” Brett said. “From the control header in the control room, everything out of that header is center pipe all the way until it hits the last coil up top. That way, when you put steam on it’s equal all the way through the entire system.”

All of this helps eliminate all the mechanical variables in the system.

“You don’t want to run a load of lumber and have problems and not know if it’s a mechanical problem or the lumber,” Brett said. “If you have the mechanical problems out of the way, you know it’s the lumber.”

When they rebuilt the Collins Hardwoods kilns, Brett said, they increased the wall height by six feet all the way around.

“What we did helped Collins Hardwoods avoid having to put a knee wall in,” he said. “With our kilns you don’t need a knee wall. People use them because they have struts on the inside of the kiln they have to protect. Our kilns don’t, so you can get right up against our walls with the lumber.”

Now that Collins Hardwoods has the kilns up and running, Andy is considering trying a unique drying approach developed by Dennis Clay, a consultant to the timber industry.

“Drying lumber is a basic energy cycle,” Dennis said. “Heat is introduced into the kiln and absorbed by the lumber, increasing the temperature and energy level in the water in the lumber, causing it to flow toward the surface of the lumber and into the airstream. To complete this cycle there must be a period of higher energy in the kiln atmosphere followed by a period of lower energy.”

Dennis said that conventional drying doesn’t take advantage of the cyclical nature of drying, but instead holds fairly constant conditions in the kiln for relatively long periods of time. He has developed a truly cyclical method of drying lumber he calls Alternate Heat/Dump Cycle (AHDC) that can dramatically shorten drying time without causing kiln defects in the wood.

“The AHDC system incorporates a time of adding energy as heat to the lumber, followed by a time when the energy level in the kiln is quickly lowered to allow the energy stored within the lumber to flow out of the lumber,” Dennis said. “When this energy flows from the lumber, it carries with it water, mostly in the form of vapor. If you were to measure the moisture loss from the lumber as it was drying, you would discover that the drying rate is greatest during the first few minutes of drying and decreases with time until you change the conditions in the kiln. Then the drying rate increases again for a period of time, followed by a decreased drying rate until conditions in the kiln are changed again. This cyclical nature of drying can be obtained by using a technique that has a period of time when heat energy only is added followed by a period of time when the energy is dumped from the kiln along with moisture that came out of the lumber and absorbed by the airstream

Though Dennis began developing the technique 15 years ago, he continues to gather data from current AHDC users. This ongoing interaction with kiln operators using his drying system allows him to make adjustments to further increase its effectiveness.

Brett said this is a totally new way of drying lumber.

“We’ve tested it in our test kiln here at BOLDesigns and have gotten green oak down to about 14 days,” he said. “Our goal is to do that at Collins Hardwoods. After they’ve run the kilns for a little while they’re going to use the new AHDC technique to dry some #3 common—which is lower quality, lower cost, lower risk lumber. If we can dry it in 14 days and have it come out looking good, we should be able to dry anything.”

Brett said the goal is to get the drying time on oak, which normally takes 30 days, down to 14 days.

“That means a sawmill can use less equipment to dry the same amount of wood,” he said. “Or they can expand and do more. I don’t know how either one will affect the market. I think eventually most everyone will have to use this system and it may bring oak prices down.”

Converting to that type of drying cycle is simple, Brett said.

“When we refurbished the Collins Hardwoods kilns, we added a control system that already has a dump-cycle type program in it,” he said. “The dump cycle is what will let us get down to 14 days on oak.”

Andy agreed.

“Converting to that system is simply a programming issue,” he said. “The kilns are set up to do it mechanically and electrically. It’s controlling scheduling more than anything else, including temperature, the venting process, and when to do it. If we put already air-dried lumber in it, there will be one schedule, and if we put green lumber in it, it will be another schedule.”

Andy thinks converting to the dump cycle has lots of interesting possibilities.

“I’m willing to try it,” he said. “It’s an interesting concept, and if it does all the things they say it can do, it will lessen the amount of lumber we have to put in air dry inventory, which ties up dollars. If it works, I’ll be able to turn the inventory faster. I’m willing to experiment with it and see if it works.”

Even without converting to the dump style drying cycle, Andy expects the refurbished kilns to have a big impact on the business.

“They’re giving us more drying capacity, which will allow us to be more selective on what we do dry,” he said. “In the past, the mill was overproducing our dry kiln capacity. We’ve done a lot of things in the mill over the past couple of years that have gotten our production up from around 5,000 board feet an hour to about 8,000 board feet an hour. In turn, that forced us into selling some products green that we really would have preferred to sell dry. These new kilns will put us in a better position to dry more lumber that has an added value from dry versus green.”

That doesn’t necessarily mean the company will sell everything dry, but it does mean managers will have greater flexibility in marketing the plant’s products.

“Everything operates off margins,” Andy said. “If the greater margin is selling green lumber, we’ll do it. By the time we put drying costs into some species and grades, the margin shrinks and we should sell those green. We had to sell green products last year that we would have preferred to sell dry because we didn’t have the capacity to dry them. The new kilns will allow us to be more selective in what we dry, and to dry around another 250,000 board feet a month.”