A successful collaboration between FPInnovations, Canfor Pulp and PulpEye has resulted in the world’s first technology for measurement of fibre wall thickness. Canfor is the first pulp producer in the world to instal the fibre wall thickness module, FWT, in four PulpEye units in their pulp mills.

FPInnovations has patented a technology for determining fibre wall thickness and fibril angle of individual fibres. The rapid and robust technology is based on an innovative light system for colorimetric-based quantification of the desired properties. PulpEye has the worldwide rights and is now commercializing the technology as an add-on technology for its PulpEye online pulp and fibre analyzer system.

Fibre wall thickness is an important parameter for pulp manufacturing, as it influences the strength properties of the pulp, but so far it has not been possible to measure it online.

“Fibre wall thickness is a fundamental kraft pulp quality attribute,” says Paul Watson, director of research and innovation, Canfor Pulp. “Having now developed a routine and robust online measurement for our PulpEye, FWT information delivered to Canfor customers should assist their product development and optimization initiatives. This has been an extremely positive collaboration which has defeated a very challenging and longstanding technical issue.”

Öjvind Sundvall, managing director of PulpEye says this Swedish-Canadian cooperation is a good example of bringing the best from each partner to develop a ground-breaking technology. “Ho Fan Jang at FPInnovations has developed and patented this technology. PulpEye has the equipment where the FWT module is perfectly integrated and Canfor Pulp took part in the development with their pulp knowledge and made the first mill installations.”

Literature from PulpEye notes that there are a number of reasons to measure fibre wall thickness online. It is an efficient method for raw material control to make sure that the mix of fibre from different sources, such as saw mill chips, roundwood from thinnings, and different species, contributes to consistent pulp quality. The FWT module can control the efficiency of a fibre fractioning process. Also, by measuring fibre wall thickness it is possible to calculate strength data and suggest the level of refining to pulp customers, helping them achieve the requested paper and board strength properties.

The FWT module is based on optical measurement of a continuous fibre stream of a controlled concentration passing the patented module. Cellulose is an anisotropic material and polarizes light in two wave planes perpendicular to each other, with different refractive indices. In the FWT module, LED light of specific wavelengths is sent through the fibre stream and the resulting light is picked up by a colour camera. The result is an image where the fibres are visualized and wall thickness is shown in different colors.