Mechanical Wood-Pulps Network

Building better refiners, one fibre at a time

Just how much can a single fibre of wood pulp be expected to take?

Placed in a device, crushed and separated, and subjected to high temperatures, humidity, transverse loading and something called "cyclic axial and tensile forces," individual wood fibres are really "taking one for the team." But their sacrifice is not in vain. It's part of important research that could result in improvements in the design of mechanical wood pulp refiners.

As the world leader in the in the production of mechanical wood pulps, Canada and Canadians could benefit greatly from this research. The forestry industry employs, directly and indirectly, approximately 1 million people and exports about $31.6 billion worth of products per year, more than 50 per cent of which is in pulp and paper. Building more efficient refiners that use less energy and produce a superior fibre can help Canada retain its competitive edge at the forefront of the wood-pulps industry.

Two researchers at opposite ends of the country run these wood fibre "torture chambers." Dr. Peter Wild is an Associate Professor of mechanical engineering at Queen's University in Kingston, and Dr. James Provan is a Professor of mechanical engineering at the University of Victoria. With the support of the Mechanical Wood Pulps Network of Centres of Excellence, they are trying to determine exactly how wood chips are transformed in mechanical refining.

Mechanical refining is the process of separating wood chips into fibres and then modifying the fibre properties so they can be made into high quality paper. Drs. Wild and Provan have designed a unique table-top instrument that simulates this refining process. A fibre is placed in the device under a microscope. Then, under computer control, it's put through its paces. The idea is to duplicate, and then study and understand the effects of the process on individual fibres. Dr. Wild explains, "If you understand the fundamental mechanisms that change fibre properties at the microscopic level during refining, perhaps you can design a refiner that does what it does in a more efficient or controllable fashion."

Understanding the effects of loads on individual fibres is just one piece of the puzzle though. Some researchers are studying those effects on bundles of fibres. Still others are looking at the whole mechanical pulping process as a continuum. "Believe it or not, there's a community of people out there who get excited about single fibres," says Dr. Wild. "It's a project that really winds up the people who are into fibre science. It's not just theoretical, it really does have application."

That potential for practical application is typical of the projects supported by the Mechanical Wood-Pulps Network. With their industrial and research connections, they can match researchers with the necessary skill sets, together with real problems that need addressing in the industrial community.

And if some wood-pulps have to be sacrificed in the interest of solving those problems, so be it.

The Mechanical Wood-Pulps NCE is one of 22 federally funded Networks of Centres of Excellence, the objectives of which are to enhance the Canadian economy and our quality of life. The program is funded by the Natural Sciences and Engineering Research Council (NSERC), the Canadian Institutes of Health Research (CIHR) and the Social Sciences and Humanities Research Council (SSHRC), in partnership with Industry Canada..