Canadian Biomass • October 2016 • Dewatering Study

One of the most challenging and energy-intensive aspects of biomass processing may soon get a little easier thanks to the efforts of researchers at the University of British Columbia (UBC).

That’s because members of the university’s math and engineering departments have developed a mathematical model that has the potential to make dewatering processes more cost- and energy-efficient, which could pave the way for advanced dewatering technologies in years to come.

Completed by four researchers over the course of three years, the study aimed to formulate a theoretical model that could predict how different solid suspensions behave under pressure. With this information in hand, the researchers are now able to precisely calculate what kind of pressure and compression speed will produce the best results for dewatering and drying different materials.

Though the study focused primarily on pulp and paper suspensions, Daniel Paterson – a PhD student at UBC and one of the study’s co-authors – was quick to point out that its applications could affect processes across a number of different fields, including biomass.

“It’s really about the optimization of pressing,” Paterson explains. “In our case, we were thinking in terms of pulp suspensions, but this can be applied to any biomass production that’s being pressed—processing sugar cane, for example, or extracting palm oil.”

Before they could begin to imagine how their findings might affect the dewatering technology of the future, however, the research group needed to put their theoretical model to the test. To do this, they placed two different suspensions – one containing nylon fibres and another containing cellulose fibres – in a compression scenario similar in design to a traditional French coffee-making press.

What the researchers found was that, in addition to their model successfully predicting how the fibres would behave when pressure was applied rapidly, the natural cellulose fibres performed better than their nylon counterparts.

“Cellulose fibres are hollow in structure, which allows liquid to escape more easily,” Paterson says. “The cellulose fibres keep larger flow paths open for the liquid to escape.”

This insight could prove key as stakeholders seek to refine and optimize biomass dewatering technologies. With a better understanding of how organic materials respond to compression, there is an opportunity to create more energy- and cost-efficient machinery, which would be a critical step in enticing more industries to adopt biomass.

“This dynamic wasn’t really considered in traditional dewatering literature,” Paterson says. “This is the little extra piece that allows the model to better capture these natural fibres. If equipment was designed around previous approaches, it wouldn’t have this extra effect to it.”

Often costly and energy-intensive, traditional drying and dewatering processes have long been an obstacle to the principles of sustainability and low energy use at the heart of many biomass initiatives. The model developed by the UBC team, however, could soon be a game changer in the development of highly-efficient dewatering machines, which, in addition to reducing energy consumption, could help to alleviate the shipping costs and material decay associated with the high moisture content of some biomass.

The research group is currently working with industrial partners to develop simulation tools for designing industrial machinery.