Eucalyptus Fibers in Greaseproof Paper Save Energy

In a study conducted in collaboration with Nordic Paper, it was found that the addition of eucalyptus fibers saved energy during production and also contributed to improved pulp and paper properties.

– My latest work has focused on improving the energy efficiency of the refining process for greaseproof paper pulp at Nordic Paper by adding eucalyptus fibers to the pulp mixture, which otherwise consists of long-fiber pulp or softwood pulp, says Björn Öman, industrial PhD student at the Exact industrial research school.

Eucalyptus fibers are naturally very fine, short, and narrow, which means they require less refining than typical long-fiber pulp to achieve the same fiber dimensions. This not only saves energy in the refiners but also results in fewer fines, which can complicate the dewatering process.

Producing natural greaseproof paper is a highly energy-intensive process, typically involving heavy refining of softwood pulp to achieve sheets with low porosity, high density, and low air permeability. This study evaluates the addition of Eucalyptus globulus—a hardwood fiber—to softwood pulp as a way to reduce the specific refining energy required for both machine-made and lab-made paper. The addition reduced the average fiber dimensions, leading to energy savings of up to 160 kWh per ton of paper produced during refining, while maintaining or improving pulp and paper properties.

– In this work, we found that refining energy could be manually reduced by 18 percent without negatively affecting any other process parameters, by using a pulp blend with 22 percent eucalyptus fibers, says Björn Öman.

This is a significant gain, as the greatest challenge with natural greaseproof paper lies in the need for intense refining to achieve sufficiently low porosity to resist fats and oils. An 18 percent reduction in refining energy for greaseproof paper can correspond to the total energy used for refining in more common types of paper, such as tissue paper.