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Monica Shaw is Editor,
Pulp & Paper
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When Bowater Newsprint started up its new recycle plant at the Coosa Pines, Ala., mill this past December, the project completion signified more than just a grade transition to 100% recycle newsprint. Instead, it was a major milestone in becoming a low-cost newsprint producer.
In 1997, the Coosa Pines mill was acquired from Kimberly-Clark (K-C) by Alliance Forest Products Inc. At that time, Alliance began looking for ways to optimize the capabilities of all its mills through strategic investment. For Coosa Pines, this meant a substantial investment to transform the mill into a low-cost facility where the company would concentrate its newsprint production. The most critical upgrade targeted for the facility was the addition of a new deink plant, which received project approval in May 2000.
In September 2001, Bowater acquired Alliance, broadening its grade mix and strengthening its position in the U.S. as a newsprint producer (see sidebar, pg. 42). Bowater also recognized the cost and strategic benefits of the deink plant (see sidebar, pg.44), so the project for a 1,450-a.d. stpd recycle plant with two deinking lines continued as scheduled.
"The mill actually had four furnishes going into newsprint before the project, and these originated from older, cost-intensive processes," describes Walter L. Brunson, Bowater vice president and resident manager at Coosa Pines. "So, the recycle plant has been a cornerstone in repositioning the Coosa facility in competitiveness and quality. Since startup, we've seen better runnability on the paper machines, as well as in the pressroom, and we're receiving favorable comments from customers."
PRODUCT TRANSITIONS AT COOSA PINES. The Coosa Pines mill was built in 1950 and currently operates two paper machines. Prior to startup of the recycle plant, the No. 3 and No. 4 machines produced newsprint made from a furnish that combined kraft, groundwood, thermomechanical pulp (TMP), and recycle. The No. 1 paper machine was permanently idled after the Bowater acquisition, while the No. 2 machine has been shut down since 1992.
In an effort to create a low-cost newsprint mill, the decision was made to install a flotation deink plant at Coosa Pines that would replace aging equipment, including grinders, TMP operations, an older deink plant, and part of the kraft mill. Not only did this older equipment equate to higher processing costs, it was also having negative effects on runnability and end-product quality.
According to John W. Graves, Bowater recycle team leader for the mill, the decision to install a flotation process rather than washing was both quality and yield related.
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A continuous belt conveyor transports deink pulp a half-mile from the process plant to Coosa Pines' newsprint machines.
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"We felt that flotation was going to work very well for ink and contaminant removal," explains Graves. "Also, with washing, you tend to lose more yield, and this is a high-yield plantßdesigned for an 85% yield with a mixture of 85% old newspapers (ONP) and 15% old magazines (OMG). So, we chose flotation to achieve both quality and productivity targets."
Design pulp characteristics included a 56+ ISO brightness with an effective residual ink count (ERIC) of less than 250 and an ash content lower than 9%. Budgeted at $113 million, the recycle plant project included two pulping lines, as well as a new 600-ton pulp storage chest at the paper mill, a whitewater system, a chemical storage facility, and a final bleaching stage to reach brightness targets.
With completion of the recycle project, the mill is now able to produce 350,000 mtpy of 100% recycle newsprint on two 330-in.-trim paper machinesßthe No. 3 and No. 4. Although the deink plant was originally designed to support the 211-in.-trim No. 1 paper machine, production on that machine was halted due to market conditions.
In addition to newsprint, Coosa Pines continues to produce 260,000 mtpy of fluff pulp in roll form.
EASY DELIVERY AT WAREHOUSE. Bowater's new recycle facility is made up of a new wastepaper warehouse, chemical receiving area, and a process building. The warehouse has specific areas for the storage of both baled and loose recovered fiber. Design capacity for the plant is 1,450 a.d. stpd with a maximum sustainable rate of 1,700 a.d. stpd.
The warehouse has eight truck doors for unloading baled paper and one trailer dump for loose deliveries on the south side, as well as four additional truck doors on the north. The warehouse is set up to accommodate 5 railcars inside the building at once, but it also employs a railcar advancer that allows a train of 10 to 15 cars to deliver at one time. As cars are emptied, they are advanced out the north side of the warehouse.
Within the warehouse, baled wastepaper is fed to two dewiring machines by forklift. The older machine, a unit from the old deink plant, can process 80 bales/hour, while the new unit, purchased as part of the deink project, processes about 103 bales/hour. After dewiring, bales are broken up in bale breaker units and dropped on the loose paper conveyor, which deposits it on the floor of the loose paper section of the warehouse.
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Located between the wastepaper warehouse and process plant, two continuous drum pulpers convert wastepaper to pulp and separate inks from fibers.
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Since the ash content in the flotation cells is critical for proper chemical processing, the amount of ONP (85%) and OMG (15%) entering the pulpers must be accurately controlled.
"We have a dual conveyer feed where one conveyor feeds OMG onto a primary infloor conveyor, and the speed of the OMG conveyor is ratio controlled to the speed of the primary conveyor," describes Graves. "Then, ONP is added on top of the OMG in the infloor conveyor, which feeds the pivoting conveyor."
The pivoting conveyor supplies feed conveyors for two continuous drum pulpers, known as the A-Line pulper and the B-Line pulper, that support Coosa Pines' two independent pulping lines. A leveling wheel control in each feed conveyor keeps a constant volume going to the pulpers, with the speed of the conveyors controlled by a set point in the distributed control system (DCS) located in the process plant control room.
In the drum pulpers, process water and chemicals are added to help convert the wastepaper to pulp and separate inks from fibers. Large unpulpable material is delivered out the end of the pulper for transportation to a landfill. Pulp from both pulpers is then pumped to a 600,000-gal pulper dump chest, where it is further diluted before entering the processing plant.
FLEXIBLE PROCESS PLANT. Bowater's process plant is housed in a new building north of the wastepaper warehouse. It contains the high-density (HD) cleaners, flotation cells, screening, cleaning, and thickening equipment, as well as screw presses that feed the HD storage chest supplying the paper machines.
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FIGURE 1. Flow of pulp through new deink process plant
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The plant contains identical equipment for the A Line and the B Line. One unique aspect of the plant is that, through valve positioning, the front half of A Line (from the pulper dump chest to the flotation accepts chest) can feed the back half of B Line (from the flotation accepts chest to the screw presses), providing process flexibility for maintenance and unexpected problems. The flexibility of the two independent lines also helps with controlling pulp supply levels and performing maintenance.
Flow of pulp. Pulp from the dumper chest is pumped to the A and B pulping lines, where it is first processed by five HD cleaners. Next, it is screened through primary and secondary coarse screens to remove contaminants such as metal and glass.
Entering the thin stock portion of the system, pulp is diluted for processing through the flotation cells, which remove inks. Flotation accepts are pumped to the 575,000-gal accepts chest and then to the primary and secondary cleaners, where rejects are sent to the remaining cleaner banks for further processing. Accepts are screened through four stages of fine screens to remove small contaminants and stickies.
After cleaning and screening, the thin stock is thickened in the disc thickener, after which screw presses deliver it at 30% to 35% consistency to a new continuous-belt, conveyor. The conveyor transports pulp a half-mile for storage in the new 600-ton HD storage chest before it is bleached at the new hydrosulfite stage and then used for newsprint production. Figure 1 provides a detailed description of the process flow.
Management approach. For the warehouse and process plant, a new self-directed, pay-for-skills team approach is being implemented at the union mill, which houses several PACE locals and several maintenance unions. Each shift crew will be a self-sufficient work team responsible for operating and maintaining the recycle plant during its shift.
"Our union leadership recognized that, to be successful at Coosa, the mill must adopt new, modern work systems that allow all employees to perform to their full potential," comments John Donahue, human resources manager for Coosa Pines. "They have supported the principles on which the team concept is based."
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Each crew at the deink plant is a self-sufficient work team responsible for operating and maintaining the plant during its shift. (shown: Theolphus Perkins, recycle team member)
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At first, maintenance personnel will work on shift with the operating crews, gaining operating skills and transferring maintenance skills to operators. This higher knowledge level among employees will bring improved operational flexibility, and compensation will be based on the employee's skill level. Management's role will then change to providing leadership and resources to make the teams effective. Also, Bowater has plans to implement the recycle plant's management approach throughout the mill.
RECYCLE PLANT STARTUP AND RESULTS. On Dec. 10, 2001, Bowater began system calibrations and water runs in its new recycle plant, producing pulp five days later. By Dec. 22, the mill had converted to 100% recycle at the paper machines. According to Graves, the project was "an immediate success." Since startup, he says the paper machines have been running cleaner and with fewer breaks. Also, the $113-million project was completed on time and under budget.
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Table 1. Furnish from the new recycle plant has improved many newsprint characteristics.
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Parameter
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Benefit
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MD Tensile strength
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+30%
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MD Stretch
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+17%
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MD Tensile energy absorption
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+50%
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MD Modulus of elasticity
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+22%
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In addition to the new recycle plant and its associated storage and bleaching equipment, Bowater also completed projects in the stock preparation and paper machine areas geared at providing uniform pulp to the machines, improving water utilization, and boosting machine efficiencies and newsprint quality. Additionally, winders were upgraded with compliant drums and soft rider rolls to improve roll condition, and paper machine chemistry changed from an acid system to neutral pH.
Creating a low-cost mill with corporate advantages at Coosa Pines
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When Alliance Forest Products purchased the Coosa Pines mill in 1997, its goal was to create a low-cost production facility for newsprint to concentrate on groundwood specialties production at its Canadian mills. In 2000, Alliance began projects at Coosa Pines to reduce production costs and improve environmental performance.
In September 2001, Bowater purchased Alliance, strengthening the company's overall product mix with the addition of SC grades and groundwood specialties, as well as fluff pulp from the Coosa Pines mill. The Alabama mill was also seen as strategically located in the Southeastern U.S., where Bowater owns three other newsprint mills located in Grenada, Miss.; Catawba, S.C.; and Calhoun, Tenn., and had the potential to attain significant cost saving synergies. At the time of acquisition, improvements were in process at Coosa Pines, but the mill still had further to go with its efforts at becoming a low-cost producer.
"There were some problems with the mill's profitability," says Walter L. Brunson, Bowater vice president and resident manager at Coosa Pines. "We don't want to dwell on where the mill was, but rather on the fact that we're positioning it to be viable for the long-term."
According to Brunson, the mill is now well on its way to becoming a low-cost producer, having dropped its cost per ton of newsprint by 11% since December 2001. The new recycle plant contributed to the cost reduction, along with other improvements, such as the switch from acid to neutral pH papermaking, which reduced chemical costs.
Also feeding into the drop in cost per ton include what Brunson refers to as "the Bowater synergies." He describes these as a reduction in transportation and distribution costs (see sidebar, pg. 44), as well as benefits from purchased materials and shared services.
However, switching from four furnishes to one recycle furnish has made the recycle plant "the cornerstone" in lowering production costs. Abandoning the inefficient mechanical pulping processes saved money, while improvements in newsprint quality have enhanced runnability, says Brunson. Also, focusing on core businesses by shutting down a woodyard, bark boiler, one paper machine, and portions of the kraft market pulp operations solidified the cost improvements.
The new recycle project, along with other restructuring decisions, has eliminated approximately 400 jobs. Though this has resulted in some "uncertainty" within the rural Alabama community, says Brunson, the facility is "moving on and focusing on saving jobs through competitive positioning."
"We've had a favorable reception in pressrooms for the newsprint," says Brunson. "Also, fluff pulp operations have been improved here over the years, and we find them a sound asset that will open doors for Bowater and ensure that this mill is an integral part of the company."
Other upgrades at the facility include approximately $70 million for Cluster Rule compliance, $40 million of which was spent on brown stock washing and screening for the fluff pulp operations, which has brought cost benefits in addition to environmental ones.
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Sheet improvements. Since changing to the recycle furnish, sheet strength characteristics have significantly improved, as Table 1 shows, while tear strength has remained the same. This has translated to bettered runnability on the paper machines and in the pressroom, says Graves.
The mill has also noted a caliper reduction from 0.0031 in. to 0.0027 in. with the recycle furnish, resulting in more paper per roll. In addition, ERIC ink count came in lower than 250. Fewer sheet breaks on the machine and in the pressroom are occurring as a result of decreased sheet defects, and water holdout has improved, which has the potential to save ink and water costs for pressrooms. Graves confirms that "most pressrooms" using the Coosa Pines paper have noted such improvements.
Coosa Pines fiber procurement brings competitive benefits
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Supplying the equivalent of 60 to 70 truckloads per day of wastepaper required at Coosa Pines means tapping fiber sources "from Chicago to New Orleans to Miami to the Mid-Atlantic," says Bowater recovered paper director, Bob Tucker.
The location of the company's Calhoun, Tenn., and Coosa Pines newsprint mills has created opportunities with regard to fiber procurement. Because of these opportunities, Bowater regionalized its Southeastern fiber procurement group, naming Dean White as recovered paper manager for that region. One of the many things White does is to study the hundreds of supply points Bowater buys from, carefully juggling ONP or OMG to the right mill.
Because recovered paper is a limited commodity, Tucker says there isn't necessarily a price advantage for purchasing higher volumes as a result of the Coosa Pines acquisition. The price break comes, however, from reduced transportation cost through optimization efforts and carrier freight savings.
"Our recovered paper group works closely with our transportation group attempting to match inbound recovered paper and outbound newsprint," says Tucker. "This is greatly helped by the proximity of the Calhoun and Coosa Pines mills, but we're still in the process of learning better ways to improve our efficiency."
The closeness of Coosa Pines and Calhoun also brings inventory control benefits.
"One mill may go down for ten days, so we attempt to juggle inventory to keep recovered paper tonnage moving," explains Tucker. "Otherwise, your supplier may find another home for their material, and that may be your competition."
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Environmental improvements. In addition to process, cost, and quality improvements, environmental benefits have been noted. Not only will the plant eliminate an estimated 450,000 tpy of waste from municipal landfills, energy consumption has been reduced by 100,000 tpy of coal. Combined with process changes in the mill, the recycle plant has decreased the mill's use of water by 7 million gal/day.
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