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September 2006 - The Logging and Sawmilling Journal

MILL DRYING

Getting more production
from the kilns

Quebec forest products company Group GDS has made an investment in new technology to achieve more accurate lumber drying and get more production from its kilns.

By Martine Frigon

According to a 2003 study on wood drying by forest products research organization Forintek and the CANMET Energy Technology Centre of Natural Resources Canada, approximately 16 per cent of wood products are over-dried and, in contrast, nine per cent is insufficiently dried. Researchers also found that wood with higher than required moisture levels is subject to additional warping. As a result of the study, it’s now known that poor estimates of drying times cause variability in moisture levels and additional production costs.

This is even more important to know today because of the need for sawmills to serve a broader range of markets. The residential market—the traditional target market of sawmills—represents no more than 35 per cent of business, compared with 22 per cent for the renovation market, 13 per cent for secondary processing and 11 per cent for packaging, according to Forintek. So it’s no surprise that sawmill managers are looking at solutions that better estimate drying times and better meet the needs of markets.

That’s the move that’s been taken by Group GDS Inc, one of the largest family businesses involved in forestry products manufacturing in the Lower St. Lawrence and Gaspé Peninsula. GDS has several divisions, including about 15 mills that process over 800,000 cubic metres of roundwood, mostly from government lands covered by Timber Supply and Forest Management Agreements, with an additional 20 per cent coming from private woodlots.

Gaston Isabel of Fabrication Delta (left) and Jean-Guy Potvin of GDS Valoribois in front of the 3Delta pre-sorter.

GDS Valoribois, which processes fir and spruce and is one of the divisions of the GDS Group, began a fingerjointed lumber line in June 2002. GDS Valoribois processes short wood pieces (four to seven feet long), dried in a low temperature kiln calibrated to reach moisture content of 15 per cent.

The plant works on two shifts during high season, but has seasonal shut-downs in the spring because the thaw makes forest roads inaccessible. Its green wood is sold in Ontario and in the US, while its dry wood is sold only in the US.

The wood used at GDS Valoribois is cut in GDS sawmills in Marsoui, Grande Vallée, and Cross-Point, all of which are in the Gaspé. The sawmills provide an annual supply of 125 million board feet.

Facing higher demand in 2005, GDS Valoribois was at a drying crossroads. “We had to decide if we should buy a new dry kiln, at a cost of $1.2 million, or try an innovative technology to control the drying,” explains Jean-Guy Potvin, general manager of the Valoribois facility. “We decided to go with innovative technology and the 3Delta.”

The 3Delta, protected by Canadian and US patents, is the result of eight years of research and development by Fabrication Delta of St Siméon-de- Bonaventure, Quebec. Interestingly, the Gaspé company specializes in the design and manufacturing of industrial tanks and wind energy equipment, rather than products for the forest industry. But they saw an opportunity and made the investment in time and money.

“Over an eight year period, we spent more than $1.5 million in research and development on the manufacturing of the 3Delta,” explains Gaston Isabel, vicepresident of business development at Fabrication Delta.

GDS Valoribois was the first buyer of the 3Delta, which sells for $450,000 per unit, and it was installed in the plant in August 2005. Sylvain Deschenes, GDS Group vice-president, believes that investment will be paid off in a very short time. Group GDS also acquired a second 3Delta for a new plant in Gaspé, which opened in September 2005.

“Nowadays, green wood isn’t in demand in the American market. They need more dry wood. So rather than investing in an additional dry kiln, we decided to go with this equipment,” explains Deschesnes.

“Although the equipment is still being broken in, it’s allowing us to reduce our margin of error and is increasing productivity. What’s more, it doesn’t require any employees,” explains Potvin. Until the new equipment was acquired, an employee had to manually classify boards going to the kiln dryers.

“Unfortunately, some mistakes occurred because of employee exhaustion from the repetitive task and some pieces were not classified correctly. Today, that employee has been transfered elsewhere and no longer has to do repetitive tasks.”

That person has more interesting work, adds Potvin, and the company has more accurately dried wood.

The 3Delta uses a two-step set-up that consists of two units, installed strategically on the production line. The first piece of equipment, the pre-sorter, is placed ahead of the lumber grader, and measures the weight, temperature and conductivity in 19/1,000ths of a second with four pickup heads, with conductivity measured at eight spots on each piece of wood.

The inspector part of the 3Delta system (left) verifies that each board is dried to specs, measuring temperature and moisture content data in real time at two different spots on each piece of wood. The system’s pre-sorter (above, inset) is equipped with four green pick-up heads that measure the conductivity of each piece of wood in eight spots.

The pick-up heads are connected to patented software that can establish the kiln duration for quick, medium or slow drying. According to Isabel, the 3Delta can work on ice-cold wood, a condition often present in Quebec sawmills.

After the pre-sorter phase, the wood continues to the end of the production line, is forwarded to the drying kiln, and returns to the planing line. The 3Delta’s second station, called the inspector, is set up at the kiln output to evaluate drying results. The inspector verifies whether each board is well dried, and sends temperature and moisture content data in real time from two different spots on each piece of wood. Driven mechanically by the same power source as the plant, the inspector and the pre-sorter are 84 inches long and 96 inches high.

“The inspector handles 125 to 130 boards per minute,” explains Isabel. “The pre-sorter currently handles 105 boards per minute, but that can rise easily to 125 and 130,” adds Potvin. The equipment has been tested to over 200 boards per minute.

The end result of all this? More—and more accurate—production. “Kiln dryers are optimized because they dry at the right duration. It allows us to dry an additional 25 million board feet in our dryers, which have a total capacity of 335 million board feet.”

According to preliminary data from GDS, its over-dried wood rate is now only two per cent while its sub-dried wood rate is between three and four per cent. “It’s much less compared to the 16 per cent and nine per cent results from the Forintek study data,” Isabel notes.

“We can’t control prices in the wood industry, but we can manage production costs,” he adds. “At the moment, more than 20 per cent of spruce is being fast-dried. If a company can guarantee its wood packages are being dried adequately, it definitely adds value to production.”

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