Dry Clean Engineered wood
Recent investments in veneer drying and auto-grading have been a boost to both efficiency and employee well being at LP’s LVL plant in Golden, BC.
By: Rick Massey
Louisiana Pacific (LP) Corp. acquired the Evans LVL mill in Golden, BC, in 1999. Since then, mill management has focused on raising production efficiency and safety awareness. As a testament to that success, the mill had gone an impressive 950,000 manhours without injury to plant personnel as of the time this was written.
That same energy has also been put into improving plant efficiency, and in the case of at least one recent upgrade, LP managed to improve both health and production performance at the same time. In 2004, a decision was made to upgrade the veneer drying system, due to the age and condition of the existing dryers. According to management, the original gear consumed too much energy, required excessive maintenance, and created an unacceptable level of smoke in the mill. After discussion with vendors, Raute was chosen to supply a complete dry end system consisting of a six-deck roller jet dryer and dry stacking system.
Less energy
Installation of the new equipment had an immediate impact on the performance of the dry end. Mill management stated that energy consumption fell by over 20%, while the dryer’s humidity control system has improved veneer quality. Recovery has improved also due to reduced over-dried and split veneer. Overall dry end productivity has almost doubled, while maintenance has been reduced significantly. Smoke from the dryers has been eliminated from the plant, which has enhanced LP’s ability to meet its mandate for worker health.
The LP Golden six-deck roller jet dryer is one of six such systems sold by Raute in Western Canada and the US Pacific Northwest since 2001. In each case, Raute has supplied the dryer as part of a complete dry-end system, which includes all infeed and outfeed equipment, a steam or gas heated dryer, camera grading, moisture analysis and automatic dry stacking.
According to LP management, Raute was chosen as the primary vendor based on a number of factors. They were impressed with how Raute packaged the project, accepting responsibility for performance from the dryer infeed to the 14th bin of the dry stacker. They also saw the solution as proven technology, based on similar projects at mills with similar needs in Armstrong and Vancouver, BC, and were impressed by the performance guarantee, which Raute has since satisfied.
According to plant production superintendent, Norm Mittgaard, the new Raute dryer, together with upgrades to the mill’s steam generation system, have improved productivity and veneer quality.
Fibre value
The mill draws the majority of its fiber from a 250 km radius, with some wood coming from coastal regions 800 km away. The mill processes fir, pine, and hemlock in production ratios of 80%, 15%, and 5% respectively. Fir is the most expensive and preferred species due to its strength properties. Pine tends to be brittle and has a lower strength rating. It is critical, therefore, that the mill processes its raw material to extract maximum value.
According to Mittgaard, the old dryers caused case hardening on the veneer surface, making the wood brittle and inconsistent in quality. Moisture content ran between 4 and 15%. Moisture is now controlled more precisely, with moisture feedback used to control dryer speed. Dryer zoning and humidity control have also improved veneer quality and overall efficiency.
The Raute dry end system includes a re-feeder, which automatically inserts sheets into the line between gaps in the flow of veneer from the dryer. By design, the mill sets re-dry at 17% to optimize drying time and stacking. Veneer that was previously run back manually through the dryer is now allowed to equalize off-line and is reintroduced automatically into the stacker infeed conveyor.
The new drying system has also reduced labour. Each of the two old dryers required an operator to feed the sheets, while several operators manually pulled, graded and stacked veneer after the dryers. The one new six-deck dryer has an operator monitoring the automatic feeding, an operator tending to the dry stacker and camera grader, and a dry end supervisor who oversees the entire operation. Random is run through an older dryer, which underwent upgrading some years ago. According to Mittgaard, the savings are significant, and are a strong justification for the investment.
On re-dry, the plant went from eight operators to one, and the intention is to eliminate the need for an operator altogether. The mill now has the option of drying veneer on the weekends, an option that wasn’t previously available to them.
New vision
The new dry end system includes a Mecano VDA G3 colour camera grader, which, according to mill management, has improved grading accuracy due to its consistent decision-making capabilities. Before the VDA G3 was brought into service, inconsistencies were seen whenever new staff were put on the grading table. By comparison, the camera grader, once programmed, will continue to grade according to data stored in memory. The result at Golden has been maximized grading and value from their dried veneer.
With respect to automatic camera grading, mill management did, however, offer some advice. While complimenting the system’s performance and ability to grade with an accuracy of over 95%, they remind us that the dry end is where many of the mill staff get their basic training in recognizing species and grades, a valuable skill that shouldn’t be lost.
According to LP management, Raute’s installation staff handled their tasks efficiently, professionally and on schedule. Installation began with the dismantling of one of the old dryers. All drying then shifted to the second of the existing dryers, while installation of the Raute dryer proceeded. The modular design of the new dryer reduced installation time.
Once the new dryer was operational, veneer was manually offloaded until the 14-bin dry stacking system was ready, at which point the two units were tied together. This final step was accomplished in a single weekend.
Training of operators and maintenance staff was done during installation, with the schedule designed to ensure that all parties were ready when the dryer went live on October 3, 2005. Final start-up of the system took place on December 4, 2005.
Installation of the Raute six-deck dry end system has enabled the LP Golden LVL mill to go from being a purchaser of outside veneer to having a surplus available for sale. They have gone from being a high energy consumer to an energy conserver, and they now believe that the upgrades undertaken at the mill will enable them to raise annual production from 3.9 million ft3 (110,000 m3) to 5.0 million ft3 (140,000 m3).
In summing up the dry end system project, mill management had high praise for all those who participated in the project. When asked what made it a success, they cited strong involvement from both vendor and customer. LP’s staff, they stated, took ownership in the project from Day One, working together with Raute to ensure success.
Rick Massey is the marketing manager for Raute, based in Vancouver when not running around the globe meeting customers and touring plants. He prepared this article in cooperation with the folks at LP’s Golden plant.
