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A new made-in-Canada bleaching technology is making paper whiter and lowering production costs at pulp and paper mills.

Same brightness, less peroxide In the papermaking process, transition metal ions in the pulp cause some decomposition of hydrogen peroxide, which is used for bleaching. As the decomposition produces chemicals that reduce brightness, stabilizers and sequestering agents are added, increasing the cost of the bleaching process. Doctors Ni and Li discovered that adding sodium hydrosulphite to a chelation removed most of the ions and led to considerable improvements in the performance of the hydrogen peroxide. They called this the Qy Process. Further work found efficiency also increased by stabilizing the remaining ions in the pulp before adding the peroxide. The improvement is known as the PM Process.

Called the PM Process, the technology was developed by Dr. Yonghao Ni at the University of New Brunswick (UNB) with funding support from the Mechanical Wood-Pulps Network and the Natural Sciences and Engineering Research Council. One of the technology's main advantages, according to a process engineer at Irving Paper, is that it doesn't require a lot of costly equipment to implement.

"It's a matter of rerouting some piping between a couple of different points in the process," says George Court of Irving Paper, a collaborative partner in the research. "Plus, by decreasing the amount of peroxide bleach that is required, we can keep running machines that might otherwise no longer be adequate."

Every year, about 20 million tons of Canada's high-yield pulp production are bleached to 70 per cent ISO or higher. If the PM Process technology were used in all applicable mills in Canada, UNB estimates the pulp and paper industry could save more than $10 million annually. It's an innovation that may never of happened without university research.

"There is not a lot of money around for research and development in this industry," says David Foord of UNB's Office of Research Services. "Most innovations are capital intensive, and equipping a mill with new tools means interrupting production runs."

As part of its marketing efforts, the university has raised $100,000 to fund a sales pitch to some 50 mills. To date, Irving Paper is implementing the process and 10 other mills have requested batch studies. Discussions on mill trials are at various stages, and a local engineering firm, Neill and Gunter, is partnering with UNB to handle further business development and coordinate implementation.

According to Dr. Ni, there are more benefits to this collaborative approach than improving the papermaking system and reducing effluents.

"This type of project is great for students," says Dr. Ni, Canada Research Chair in Pulp and Paper Science and Engineering and director of the Limerick Pulp and Paper Centre at UNB. "They visit the mill, talk to people about their ideas and work on something that is used in the real world. They also get lots of practical inside information on the process and have access to equipment not available on campus."

Dr. Zhiqing Li, a graduate student who co-developed the technology with Dr. Ni, is proof of that. Irving Paper hired him as a process engineer. Two other students are working at other mills on collaborative projects.

The Mechanical Wood-Pulp Network reached the end of its funding cycle in March 2002 and is reinventing itself, with financial assistance from the Networks of Centres of Excellence (NCE) program, as PAPIER, a national organization of academic researchers focussed on improving the technological competitiveness of the Canadian pulp and paper industry.

Dr. Ni credits the NCE's financial support and its emphasis on university/industry collaboration for moving this research from the lab to the market. "We wouldn't have been able to do this otherwise," he says. "This research really focused on finding creative solutions to real-world problems."