January/February 2003
At Smurfit-Stone’s linerboard mill in Fernandina Beach, Fla., OCC is a small but important source of fiber both for the company’s products and its commitment to environmental protection.
By Bobert L. Ried
Old corrugated containers (OCC) represent only about 10 percent of the raw material used to make linerboard at Smurfit-Stone Container Corp.’s Fernandina Beach mill, which operates within a short drive of the beaches and resort hotels of Amelia Island, near Jacksonville, Fla. But recycled fiber is far more essential to the mill’s operations—as well as its corporate citizenship—than that number suggests.
For one thing, though the roughly 65-year-old mill originally used only virgin pulp, that’s no longer an option. The mill first put in a recycling plant in the early 1970s, then rebuilt its papermaking machines in the mid-1980s to increase overall capacity and boost its use of recycled fiber, which had been negligible up to that point, says Mike Holden, production manager. As a result of those rebuilds, however, “we can’t furnish the machines with just virgin fiber,” he explains, “so we had to have recycled fiber to supplement.”
Moreover, the mill’s setting on this tiny, vacation-oriented barrier island—just 2 miles wide and 13 miles long—also makes environmental awareness a key concern. Indeed, in addition to using recovered fiber, the mill is designed to recycle or reuse nearly everything consumed during the papermaking process, from water to chemicals to the bark of trees chipped for virgin pulp. “About the only things we landfill here are the rejects from the recycle process—we can’t recycle those,” says Holden.
But just because the mill must always use some recycled fiber doesn’t mean that it will lower its quality standards for the material, nor will it ignore important economic considerations. OCC offers both advantages and disadvantages in manufacturing the mill’s linerboard, which is used as the top and bottom layers of corrugated containers, notes Todd Hunt, who manages the mill’s recycling processes. For instance, where “stacking strength” is key—that is, when the linerboard will be used in boxes that must sit one atop another to a certain height—the shorter fibers from recycled material can create problems. But when puncture-resistance is more critical than stacking strength, the OCC provides benefits. Also, OCC fibers can actually assist with the drainage portion of the water-intensive papermaking process since the fibers have already been processed once and do not retain much water.
“We push to use as much recycled as possible,” says Hunt, so when OCC prices were “favorable” at the beginning of 2002, “there was a big push to use more.” When the price of recovered fiber nearly doubled last summer, the emphasis switched back to virgin pulp, which offered greater fiber strength at a more economical price, Hunt notes.
On a daily basis, the Fernandina Beach mill turns about 200 tons of baled OCC into recycled pulp, which after extensive cleaning and screening is mixed with virgin pulp to produce roughly 2,300 tons a day of linerboard. The plant’s two paper machines drain, form, press, and dry the resulting sheets of linerboard, which range in weight from 35 to 69 pounds. (Grades of linerboard are based on the weight of a 1,000-square-foot sheet, Holden explains.) The mill also used to operate a third papermaking machine—one designed to handle more recycled fiber—but a slowdown in the paper industry forced Smurfit-Stone to close that unit about two years ago and move its production to another facility, Holden says.
Though all of the mill’s products include some recycled material, the heaviest-weight sheets tend to use the most recycled fiber, Hunt points out. Thus, while the mill uses roughly 10 percent OCC overall, the 69-pound linerboard can have as much as 15-percent recycled content.
Sourcing and Sampling OCC
Some 10 to 12 truckloads of baled OCC arrive at the Fernandina Beach mill every day. Those bales are stacked either in an outdoor storage area that can hold roughly 3,000 tons of inventory or inside the recycling plant itself—a roughly 5-acre facility adjacent to the mill that has room for storing another 1,000 tons of OCC under roof. The mill’s OCC feedstock comes primarily from four sources (listed in order of tonnage):
• grocery store chains;
• municipal waste authorities;
• Smurfit-Stone’s own reclamation centers throughout Florida; and
• brokered tonnage that can include fiber from independent scrap paper processors.
The first three sources account for as much as 85 percent of the mill’s recycled fiber supply, Hunt says, with brokered amounts comprising the rest, though some of the Jacksonville reclamation sales office’s material can come from smaller packers.
Regardless of where the fiber was sourced, the arrangements for its purchase and delivery are all handled through the Jacksonville center, which is part of a separate division within the overall Smurfit-Stone corporation. The mill and the Jacksonville sales office maintain daily communication and based on production demands arrange deliveries of the bales to be sent from its own inventory, brokerage facilities, or directly from suppliers such as grocery stores with their own baler and trucking arrangements.
“It makes it nice on our end that [the Jacksonville sales office] can handle a lot of the logistics and we handle the operations and receiving,” Hunt says.
The Jacksonville sales office also listens to the mill’s feedback on quality issues and acts as a middleman when necessary, sometimes even arranging for mill officials to meet with a supplier to resolve any major or persistent quality problems, Hunt notes.
Quality is always a priority at the ISO 9000 mill, which established a bale-sorting report system as part of its efforts to obtain the ISO quality certification. As bales are unloaded at the recycling plant, employees watch for moisture problems—“we’re buying fiber, not water,” Holden stresses. The workers also randomly break open the bales, remove all the contaminants and prohibitives, and then compare the weight of those outthrows with the amount of good OCC in the bale. The target is 5 percent with no more than 10 percent outthrows by weight, with a detailed report provided first to the mill’s recycling manager and then to the Jacksonville sales office so it can, in turn, provide feedback to suppliers.
OCC from grocery store sources is usually so good that the mill doesn’t normally have to check that material, Hunt says, with the Smurfit-Stone reclamation centers’ material next in quality, followed by the municipal fiber and the brokered tonnages, both of which will typically include more outthrows than the first two sources.
Chewing Up Bales
After the quality inspection, OCC bales are stored until needed, at which point mill workers will cut but not remove the metal wire around the fiber and send the bales up a conveyor to the hydrapulper. This 20-foot-diameter chamber works like a giant blender, with a rotor at the bottom that chews up the OCC while the fiber is flooded with brownish water recycled from the later stages in the recycling process and the papermaking process.
To extract the metal wire from the fiber slurry, a steel cable is dipped into the hydrapulper. The cable catches the wires and continually builds upon itself. As this cable and wire grows, it is removed and cut. During the pulping process, though, which makes the floor around the unit tremble, the cable whips back and forth within the hydrapulper’s metal walls like the tail of an angry Florida gator. Other heavy contaminants collect at the bottom of the unit, where workers have found everything from metal screws, automobile parts, spare change, and once even a diamond ring.
From the hydrapulper, the now mostly fluid fiber—only about 3 percent solids—moves to the first of a series of cleaning, screening, and storage stages. These begin with a high-density centrifugal force method in which a conical-shaped device spins the material so that specific gravity separates out the heavier “reject” contaminants, which sink to the bottom for collection, while the lighter “accepts” spin to the top and continue on.
Next, the slurry “stock” moves from a storage chest through a bank of high-density conical cleaners, then waits again in a storage chamber before being pumped into the medium-density cleaners, called fine screens. Most of the big, heavy contaminants are now gone, Hunt says, so the stock is forced through two stages of fines screens, which involve a rotating assembly with blades that force the fiber through small slots in a stationary basket. The accepted fiber is pushed through a screen to the outer cavity of the unit while the contaminants that are larger than the screen slots drop to the bottom and are removed.
Rejected material throughout these various processes then goes through further screenings to extract any lost fibers before ultimately being sent to a press that extracts any remaining water. Just as the mill doesn’t like to pay for moisture in its incoming OCC, it also wants to send nothing but solid material to the landfill—certainly not liquids that can be recycled through the mill’s systems, Hunt notes.
After fines screening, the stock moves on to the Beta low-density cleaners, a trio of units located on part of the roof of the recycling plant building. Flowing through first the 500 small cones of the primary Beta and then the 250 cones of the secondary Beta, the material now goes through a reverse of the earlier cleaning methods. The fiber itself is now the heaviest material, Hunt explains, while the contaminants are lighter things such as adhesives, stickies, and Styrofoam. Now the accepted material sinks to the bottom of the cleaner cones while the rejects float up.
A third Beta cleaner, X-clone unit, and Krofta are then used to clean and recover usable water for the hydrapulper while separating out sludge that ultimately will be treated and incinerated. The fiber-rich stock from the primary and secondary Beta units, meanwhile, heads up to the Decker, which consists of a rotating drum 26 feet long and 13 feet in diameter. As the OCC pulp flows over the Decker drum, the vacuum seal leg creates a vacuum whose suction draws the water through the drum’s wire mesh surface.
This is the final stage in which the OCC slurry is handled separately from the virgin pulp, Hunt explains. It is also the last chance to visually inspect the fiber for contaminants before the stock is pumped into a 400-ton storage tower, where it waits until it is needed by the papermaking machines.
Making Virgin Slurry
While old corrugated is being pulped and cleaned, a somewhat similar process is creating a virgin slurry that ultimately will be blended with the OCC pulp at a ratio of about nine parts virgin to one part recycled.
More than 300 tons of virgin wood arrives at the Fernandina Beach mill every hour as softwood logs and wood chips. Piles of logs are fed as needed into a water flume that carries them to debarking drums. These drums prepare the logs for cutting into chips by using friction to remove the bark that is then recovered to use as fuel in the mill’s boilers, which produce both steam and electricity for the pulping and papermaking processes. Next, the mill-produced chips and the purchased chips are screened for size and either cut into smaller pieces and processed in a continuous digester or one of eight batch digesters. The digesters act like giant pressure cookers to break down lignin—the substance that holds wood fibers together—in an alkaline solution called “white liquor” that also removes impurities.
By the time the digesters send the fiber and chemical slurry to a screening and cleaning system, the white liquor has turned black from all the impurities it has absorbed. The pulp is washed free of these chemicals, which are then recovered for reuse in the virgin pulping system.
At this point, the virgin pulp is ready to be mixed with recycled pulp and converted into linerboard.
Coming Together
The actual papermaking process begins as the two slurries are blended together in the proper consistencies for each type of linerboard being produced and then fed onto the two 240-inch-wide Fourdrinier paper machines. At the start of the process, the material—which is fed onto a fast-moving, continuous screen called a “wire” at the front end of the Fourdrinier machines—consists of about 99.5 percent water and only 0.5 percent fiber, notes Holden.
But, as he explains, “the whole paper machine is one big water-removal process.” So as the virgin/recycled slurry is carried along, the water is constantly being eliminated—first by gravity as it drains through the openings in the wire screen, then by pressure as a series of rollers and felts squeeze out the liquid, and ultimately by evaporation as some 76 steam-heated rollers on one machine and 96 rollers on the other dry out the linerboard sheet. What began as less than 1 percent fiber at the front-end of the machine reaches about 26 percent fiber as it shifts from the wire to the press section, then 45 percent fiber as it moves into the thermal dryers, ultimately exiting the Fourdriniers at roughly 94 percent fiber and just 6 percent water, Holden says.
The result is a 30-ton roll of linerboard that is then transferred to a winder, where blades cut this jumbo roll into individual rolls to meet customer specs—usually about 12 smaller rolls of 2.5 tons each.
About 90 percent of the linerboard produced at the Fernandina Beach mill is then shipped to other Smurfit-Stone facilities around the country, where it is combined with a fluted inner medium (usually made from 100-percent recycled fiber) to manufacture corrugated containers. But a certain amount of the mill’s production also stays right at the Fernandina Beach complex—it’s simply carried over to the adjoining box plant that, despite its proximity, is actually part of an entirely different Smurfit-Stone division.
Challenges and Expectations
Given the current paper market, the Fernandina Beach mill doesn’t plan to increase or decrease its use of recycled fiber by any great amount. The mill’s raw material mix seems to be balanced nicely to meet its current needs.
Obtaining adequate supplies of quality OCC, while never actually a problem, can at times involve challenges that are beyond the control of both the mill and its suppliers. For instance, just being located on an island along the East Coast means that the mill can only draw recovered fiber from a 180-degree radius around its facility rather than the 360-degree “wood basket” that many inland mills enjoy, notes Holden.
And then there’s the increased use of glues, tapes, and adhesive labels on boxes that creates a growing problem with stickies. Even international factors such as China’s growing demand for recovered fiber and its impact on domestic OCC prices can create uncertainty about raw material supplies, given the mill’s need to remain competitive and hold down operating costs.
The mill does, however, ask for and expect cooperation from its suppliers on the things that they can control, notes Todd Hunt. For instance, paper recyclers in Florida often store their inventory outside, which can create moisture problems. Hunt, in fact, has seen shipments of OCC that had turned black and smelled moldy from exposure to too much rain. Other bales contained large debris such as broken pallets or trash.
Fortunately, Hunt adds, suppliers are usually willing to make improvements, especially when Smurfit-Stone’s Jacksonville reclamation sales office arranges a face-to-face meeting between mill personnel and paper recyclers.
“We don’t want to turn away a supplier, so we’re willing to work with them,” Hunt says. But if problems are documented and communicated and still continue, “we will turn those trucks around.” After all, he stresses, “we’ve got a business to run and we’ve got to make smart business decisions.” •
Robert L. Reid is managing editor of Scrap.
At Smurfit-Stone’s linerboard mill in Fernandina Beach, Fla., OCC is a small but important source of fiber both for the company’s products and its commitment to environmental protection.