Weyerhaeuser Company’s new US$80m Louisiana particleboard line at Simsboro, near Ruston, Louisiana, is in successful start-up after 16 months’ construction work. Classified as a modernisation, it amounts to the newest particleboard plant in the US. The product is called Ultra Pine.
The line’s capacity is more than 240,000 million ft2 annually, more than doubling that of the old mill started in 1971. On the environmental front, water consumption has been cut by 10% and air emissions limited, despite the doubled production.
Most of the work was accomplished under the previous owner, Willamette Industries, which was recently absorbed by Weyerhaeuser. But the near-flawless start-up is under the Weyerhaeuser flag. Manufacturing space is 510,000ft2.
General manager Darrell Keeling explained the background: “We started thinking about replacing this mill three years ago. The ultimate decision was to build a new particleboard mill in Carolina and rebuild here. One of the big things was the rail service and the people here. The east-west line that comes by the plant is one of the major southern main lines.”
He continued: “The main focus was to replace the old multi-opening press with the most modern technology we could buy and that was the continuous press. We wanted to be as automated as possible. The old plant had a lot of forklift handling which could result in product damage. The Lukki system took care of that.”
One goal was to provide customers with any desired size panel. With the previous 16ft multi-opening press they had been rather restricted. If a customer wanted a 12ft panel, a four foot tail was left. Now they cut a 24ft without loss.
All the mill’s production is sawn to order. Weyerhaeuser’s sales department, located in Fort Mill, South Carolina, handles sales for all particleboard and MDF and sends a weekly schedule to the mills. Locally, the schedule is optimised by master panel size yielding the least waste. The orders are input into the system to be filled at the saw.
Project manager Martin Elshout outlined: “The production line has a press operator, a line utility, and a couple of labourers for clean-up. Two people can run it from blending to the stacker. Most of the crew of 21 works in the finish end, taking panels from the saw and strapping.
“We are shipping up to 1,000 miles, but our primary target is going to be the Mississippi and Ohio valleys, and the upper Midwest. The Indiana furniture market has been one of our best markets,he said.
The board properties are similar to the old mill’s, but the board can be four or five pounds lighter with reduced density. Instead of a 49lb or 50lb board, the line can run a 44lb or 45lb board.
Mr Elshout explained: “The continuous press technology and continuous line enables us to do that. Even though the board will be lower density we will still be able to make, or exceed, the same performance criteria as the old line. We’re just doing it with less density because of the consistency.”
Willamette engineers planned out all the concepts and equipment selection. Final engineering was accomplished by Mid-South Engineering Co, Hot Springs, Arkansas, with project management by Willamette’s Bob Duhé.
Blending, forming, pressing, sanding and sawing is all new along with two new core dryers. With some modifications, the mill maintained its hammermills, and screening room, which were moved to the new building.
Half the incoming shavings and sawdust originates in Weyerhaeuser sawmills and the rest comes from the market.
In the old mill installation trucks had to unhook from their trailers to unload, but the new Phelps truck dump handles both as a unit. Formerly, raw materials were stored outside, but a new building provides cover from the elements.
A Cat 950G front-end loader moves material from storage to the Pal roller screen to pull out the acceptable fines which go straight to the face dryer. Face overs are hammermilled. Core accepts go to the steam bin while overs are processed in a Jeffrey hog before steaming in a stainless steel vessel to soften them before refining in two Andritz 2,500hp units. There are four such refiners.
Flaps under the screen are adjustable to balance core and face material leaving the screen. All the silos are SHW. The mill has one screen for core refining and another for face refining. All the incoming plywood trim goes into core. “We don’t want ply trim in the face,said Mr Elshout.
Part of the rebuild was the addition of a small Clayton 10,000lb/hour gas-fired steam generator, which replaced a much larger 30,000lb/hour steam boiler.
Green sawdust is pre-dried down to 25% moisture content in a Westec triple pass dryer before joining the dry shavings and final drying. Dry core material drops into the 80-unit dry core bin, ready for the blenders. Dry face material is transported in a high pressure blower system to a 60- unit face bin. Westec silos are installed.
Exhaust fans over the press and board cooler pull air into a duct to the four dryers and then to the Geo Energy RCO. This can be by-passed directly to the RCO.
“We considered separate systems from the press and the dryers but we didn’t really want to recirculate the gases out of our dryers. We did this to cut down on the sheer size of the RCOs. We have about 300,000ft3/minute capacity through our RCOs,said Mr Elshout.
The mill has two face and two core resin tanks and tanks for urea, wax, and catalyst. Dynea currently supplies the resins.
Dosing heads on the top level feed through the bins into the Imal blenders where the resin, wax, urea and water mix on through the blenders. Injection screws add sander dust in the blender just after resin is added. This is mainly for the faces. None of the sander dust is burned. Then it’s on to the Metso Classiformer line.
The forming line, pre-press and press are all Dieffenbacher. The 10ft-wide 28- frame press is 36m long, operating at 410°F to 420°F, heated by thermal oil. Ten pumps circulate thermal oil, leaving the heat exchanger at 475°F, through 10 heating platens. Two main steel belts run on 9,000 rolling rods.
An automatic GreCon unit on the offbear side continuously monitors densities of the two surfaces and core with an Imal blow detector and thickness gauge also on-line. Automatic saws cut to master panel lengths.
Average thickness will probably be somewhat less than 5/8in. “The thinner board runs better on a continuous press and I think in good market conditions we’ll push for the thinner product,Mr Elshout predicted.
The new continuous line means greater consistency. On the old multi-opening line, panels came out of the press at 0.06in to 0.10in over nominal thickness, while 0.02in is average on the new line. This means real material savings.
And thickness is more consistent across the board. Any inconsistencies would be quite apparent when thin paper overlays are employed in final board use.
Corvallis Tool (CTC), made the transport equipment from the blow detector to the offbear side of the grading and stacker.
Pressing, sanding, sawing is the normal manufacture order. The sanding line is Metso with an Imeas sander followed by an Imeas cross-belt sander. The cross-belt is Imeas’ first for wood products.
The tracked Lukki system handles stacks on steel pallets. It automatically moves bundles around, remembering their location and contents. The carrier has a 50,000lb capacity and receives its computer instructions from a radio antenna in the centre of the storage area. Metso furnished the computers.
At the computer Mr Elshout described the Lukki operation: “It shows me size, thickness, and number of pieces. If I want to know when it was produced, I can come here and I’ll have the production date and when stacking started. That particular bundle is 5/8in. It shows what time we started sanding it and what time we finished.”
The computers are located in the sanding and saw control rooms. Either of these operators may order the board they want.
Every pallet has its own code which applies to the Schelling book saw. The Schelling orders boards and cuts them for the final product, after which new bar codes are applied. The Schelling handles books 81/4in thick. The line is followed by three stacking stations and two automatic strapping lines.
Flamex fire detection is installed throughout the system and there are two water ponds for fire emergencies.
Shipping is evenly divided between rail and truck with major markets in the US South and Midwest. Indiana, Ohio, Arkansas and Texas are important.
Mr Elshout said the project had an excellent construction safety rate. “Our employees have really done a good job. Being part of the new project and continuing to run the old plant was a major challenge. We have a training centre in the front office. The first step was to get many of our veteran employees computer-literate. We wrote job manuals for the new equipment and many vendors helped with the training.”