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Pulp Non-Fiction New papermaking technology truly means less is more. By T.J. Becker |
A new technology being commercialized by an Atlanta company yields stronger paper, while using less fiber and energy, translating into lower costs for paper manufacturers and good news for the environment.
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The technology applies to the heart of papermaking — formation of the fiber network. It was invented by Dr. Cyrus Aidun, professor of fluid dynamics at the Institute of Paper Science and Technology (IPST) and adjunct professor at the Georgia Institute of Technology's School of Mechanical Engineering.
When paper products are made, wood fibers are first suspended in water, then drained and applied on moving screens to be pressed and dried. Because of the hydrodynamic characteristics inherent in the production process, fibers tend to orient in the direction of the machine, rather than spreading uniformly.
The result is an irregular network of fibers that has been an industry problem since high-speed paper machines were introduced more than 40 years ago. An irregular fiber network causes paper to curl, instigating paper jams in photocopiers and laser printers. Also, paper remains weak in the cross-machine direction, which is why it's easy to tear an article from a broadsheet newspaper lengthwise, but not horizontally. Though this may not matter to newspaper readers, strength is a crucial issue in the packaging arena, where cardboard and corrugated products must measure up to designated standards.
Aidun's invention is a redesign of the flow mechanism in the fiber network-forming process and represents several years of research and development. He spent considerable time studying the fluid dynamics of the fiber-forming process and learning why fibers orient toward the direction of the machine.
"Once we understood the physics, we then altered the hydrodynamics by introducing the correct vorticity field to disperse fibers uniformly in all directions," says Aidun, explaining that vorticity is the circulation of fluid elements around an axis.
Aidun achieved the desired vorticity field with a device that is retrofitted
into an existing paper machine's headbox. The device comes in three forms — mechanical, electromagnetic and ultrasonic.
By increasing the uniformity of the fiber network structure, Aidun's VORTIGENTM System results in two major benefits: (1) Paper products become stronger and more uniform; and (2) tremendous savings are realized in raw materials. That extends not only to fiber, but water, energy and additives used in pulp and papermaking processes.
"This technology will rank among the top advances in the papermaking industry over the last 25 years and should continue to be cutting-edge well into the 21st century," says E. J. "Woody" Rice, vice president of IPST. A graduate research university based in Atlanta, IPST is a global leader in pulp and papermaking research and maintains a research alliance with Georgia Tech.
"This could really change the properties of all grades of papers and should lead to wide range of new development in converting and packaging design," Rice adds.
Although the VORTIGEN technology applies to a wide range of paper products — from lightweight tissue to heavyweight grades — researchers are focusing initial commercialization efforts on the packaging arena. It is the largest segment of U.S. papermaking in terms of volume production.
Aidun already has conducted pilot tests with a small-scale model of the
mechanical device. On average, this model yielded a 10 percent increase in strength and a 10 percent decrease in raw materials for packaging products machines.
With the average machine using 250,000 tons of fiber each year, VORTIGEN
is expected to decrease fiber consumption by 25,000 tons — translating into an
annual savings of several million dollars per machine. What's more, companies would also save in energy use and water consumption.
"An enormous amount of water is used in pulp processing (200 or more parts water for every one part fiber)," Aidun says. "Considering that there are more than 8,500 paper machines in the world, and that the paper industry is the second largest industrial consumer of energy, the savings in energy consumption and the environmental impact would be significant. The industry will invest to broadly implement the technology because it will pay for itself in a few months."
Commercialization efforts are under way already. In 1998, IPST granted an exclusive worldwide license of the technology to Fluidix Microforming Systems, a start-up company housed in the Advanced Technology Development Center (ATDC), Georgia Tech's incubator for fledgling firms with a high tech focus. Aidun is president of Fluidix with Diane Murdock, a paper industry veteran, serving as vice-president.
A full-scale commercial version of the mechanical device is being constructed by Fluidix through a project funded by a consortium of 30 paper companies. Aidun expects it to be in operation early this year in a Florence, S.C., plant owned by Smurfit-Stone Co., the world's largest manufacturer of packaging products.
Still in development through a U.S. Department of Energy-funded project are electromagnetic and ultrasonic-controlled devices, which should be ready for pilot tests within the next year or two with commercialization occurring within five years.
"The mechanical device is very appealing to the industry because it is simple to install and operate," Aidun says. "Yet I consider the field-controlled devices
(electromagnetic and ultrasonic) will be the ultimate systems to be used because they offer superior control and on-line profiling capabilities."
"Fiber is a huge issue for the paper industry," Murdock says. Not only is the cost of fiber at stake, but supply is also a global concern, she explains: "People in the industry are extremely excited about the opportunities this new technology represents for their companies."
For more information, contact Dr. Cyrus Aidun, Institute of Paper Science and Technology, Atlanta, GA, 30332-0620 (Telephone: 404-894-6645) (E-mail:
cyrus.aidun@ipst.gatech.edu)
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