Longer is better at LP
Louisiana-Pacific has invested over $30 million in its OSB mill in Saint Michel des Saints, QC to optimize the fibre infeed and maximize fibre recovery.
By: Guy Fortin
Since 2000, Louisiana-Pacific has been busy expanding OSB production at its plant in Saint Michel des Saints, QC, by almost 12%, climbing from 450 ft2 that year to over 500 million ft2 in 2006. The most recent project was a $30 million bid in 2004-2005 to boost production and recovery in the mill’s green end. The mill optimized log bucking to handle its supply of crooked aspen and birch, installed three brand new generation stranders from BC’s Carmanah Design & Manufacturing, added a new Fuji King rotary debarker, and enlarged four hot ponds to handle the 12-ft logs the mill now brings in instead of the original 8-ft logs the mill was built for.
As a result, LP Saint Michel now recovers over 10% more usable fibre from the same log supply. Less fibre is lost during slashing and re-sawing, and log pieces are now handled much less, all leaving more for OSB manufacturing, key to the mill’s competitiveness, as mill manager Robert Verreault explains.
“Our fibre comes from a long way away, so our costs are higher than our competitors. That means we have to maximize the recovery from each log we bring in. The less slashing and re-slashing we do (i.e. 12 ft stems instead of 8), the less we handle the logs, the less loss we have. Before this project, we added in 2000 two new GTS energy systems with capacities of 240 million BTU/hr and a fourth drier, this one an Alpha.”
All tolled, LP has invested over $50 million in the OSB plant to boost production and efficiency since acquiring it as part of its FOREX purchase in 1999. In fact, Verreault recalls that the mill actually offered some excellent opportunities for expansion. For starters, the original office space was vastly insufficient at 2,400 ft2, but was situated in the heart of the mill, so that by adding a new threestory, 12,000 ft2 office building, LP managed to free up space inside the mill.
“This space allowed us to increase drying capacity, with a little re-working, so that everything could be done inside the existing mill walls, except for the new offices of course.”
Optimized infeed
Surrounded by a vast wood yard that holds upwards of 200,000 m3, the LP Saint Michel mill consumes about 15,000 m3 per week of aspen (65-68%) and birch. Prior to the recent upgrade, logs were all slashed to 8-ft stems, fed through a pair of 27-in Nicholson A5 debarkers, and then re-slashed ahead of the original Block Flakers. Not only did the mill have to re-slash the stems, but it also had to remove deformed and over-sized (28 inches) pieces ahead of the hot ponds. Considerable wood and time was lost.
This dilemma was solved by adding a Comact optimized bucking station, building wider hot ponds (13.5 ft), adding the three new generation SmartDISC stranders with batch feeders from Carmanah, and adding the 60-ft long Fuji King.
Logs now coming to the mill are fed by a stationary Tanguay loader and Comact wave feeder to the Comact 10-saw slasher. The station is fitted with a linear scanning system that seeks to maximize the number of 12-ft sections from each log. A conveyor then takes the slashed logs to a second Tanguay loader, this one a rail-mounted PL 430, which sorts the stems by species into four 13.5 x 165-ft long hot ponds.
After an 8-hr retention time (40 degrees Celsius or higher in winter), logs are sent according to species and diameter towards one of three debarkers. Relatively straight aspen stems below 27 inches are sent to two Nicholson AB debarkers. The new Fuji King handles any stems that are larger than this, as well as stems with excessive crook or other defects, an addition that has greatly increased production.
“Before, all the over-sized logs, as well as the deformed logs had to be re-slashed and re-routed to the ring debarkers. Now, the loader operator just directs those to the pond that feeds the Fuji King rotary debarker,” explains Bernard Laforest, training supervisor for the mill.
Bark is conveyed to a Rawlings hog and stored in an S. Huot bin ahead of the two new GTS boilers. For their part, stems continue on to two log decks, which in turn feed the three batch feeders ahead of the Carmanah stranders. Each strander creates specific strands – one for centre strands, which will require a 3% moisture content (MC) on the forming line; one for surface strands (6% MC on the former); and a third for special order strands among others. The older stranders were fixed block models handling 3-ft stems, while the new ones are long log designs in which stems are arranged by batch feeders and the stranders move toward the stems for uniform strands.
Strands then go to four wet bins ahead of drying. When the mill was launched in the late 80’s, it had but two MEC triple-pass rotary dryers. In 1996, a Rader dryer was added, and then LP added the Alpha in 2000 soon after buying the plant. The latter two are powered directly by the GTS energy systems, which at 240 million btu/hr have greatly increased the mill’s original 60 million btu/hr capacity. The new capacity allows ample heat for the hot ponds, the two rotary dryers, the wax reservoirs, plant heat, the press, and even for the kilns and planer mill of the adjacent sawmill complex.
Pressing on
Two of the four rotary dryers handle strands for the surface layers, while two handle those for the centre requiring lower MC levels. Three blenders follow, adding wax and resin according to strand type, after which the treated strands are conveyed to the four forming heads that start off the Siempelkamp Combi Line. The 16-opening press is a little different than most at 25-ft wide, allowing it to make 9-ft panels as well as 8-ft products to suit market needs, a welcome flexibility in current markets Verreault adds.
Formed mats are cut into 8 x 24 or 8 x 25 ft sections depending on orders, and loaded into the pre-press section. Once in the press itself, the 16 master panels are pressed at 215 degrees Celsius and 4,400 psi for a little over three minutes for 7/16” panels. Pressed panels cool and are sent to a Globe finishing line, where they are sawn to finished size and sent through a tongue & groove station as required. All products are packaged in 4,000 lb bundles, with the number of panels varying according to panel thickness. After the paint booth (orange for regular products, grey for T&G), panels are strapped by a Signode strapping machine and set aside for a 48-hr cooling period before shipping.
Some 90% of production is made up of regular panels for the construction industry, while 9-ft and T&G products make up a little more than 10% of production. Since renovations that involved adding a second finishing line, the mill also makes 1 1/8” panels that are 8- to 12-in wide and 12-ft long (Rimboard) for use in I-beam manufacturing. This new product accounts for between 2% and 4% of finished production. Mill managers add that the constant pace of production and efficiency improvement over the past six years involved much more than just adding new equipment. The 165 employees who work the mill’s four shifts must also be taken into account, Verreault adds.
“I have been in this job for a little over two years, and I have to say that I am very impressed with the motivation and commitment of all the employees in this region. They have been on side since Day One, and they continue to work with us on all fronts to improve the production processes and working conditions.”
Indeed this obvious enthusiasm permeates the entire complex, leaving little doubt that there is room for even more improvement to come. After all, LP Saint Michel has the room, manufacturing flexibility, and staff to succeed.
Guy Fortin is editor of Opérations forestières et de scierie, Canadian Wood Products’ sister publication serving the Quebec market in French.
