Biochar: A high value-added forest product

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Is biochar production a key to the forestry bio-revolution?

Natural Resources Canada recently funded an innovative project that brought together the expertise of FPInnovations, Airex and Cyclofor. The objective was to find a way to enrich the forest biomass, a low-value raw material normally left behind on Québec’s tree harvest sites.

The project headed by Alain Chabot and seconded by Alpha Barry and Brian O’Connor, all from FPInnovations, enabled Airex to develop a pilot-scale torrefaction unit (CarbonFX) with the capacity to produce 250 kg of biochar per hour from wood fibre. Cyclofor was in charge of providing forest biomass while FPInnovations evaluated the environmental impact, described the biochar output (caloric value and levels of ash, humidity, carbon, etc.), analyzed results and coordinated the project. According to Airex President Guy Prud’homme, the addition of measurement aSmailnd control elements to the biomass processing, coupled with improvements to the CarbonFX design made it possible to produce homogeneous biochar using minimal labour. Cyclofor VP Alain Brodeur was delighted with the quality of products generated by the new process. Through of the project, 55 to 75% carbon content was quickly attained, thereby producing high calorific value charcoal. Preliminary trials have even produced carbon content as high as 85%. These results could lead to replacing bituminous coal in high-value added applications in areas such as food, textiles, medicines, gas and water treatment, metallurgy, and soil rehabilitation.

A Optimized technology

Airex’s technology involves two phases. The initial conditioning phase occurs while the biomass is transported to the reactor. This phase increases the biomass temperature and lowers its moisture content. Results show that this step is important for obtaining various grades of charcoal. During the second phase, the material is transferred to a reactor where the biomass is converted into biochar. The conversion occurs at high temperature and lasts only a few seconds. Biogases, which are the gases emitted during the torrefaction, are continually routed to the burner where their combustion helps maintain an optimal process temperature. Airex’s technology is highly energy efficient, yet simple and robust, reducing the cost of producing biochar.

Favourable context

The time is ripe for the research and development of biotechnologies based on forest biomass: energy costs are forecasted to rise, governments continue to want greenhouse gas reductions and the forestry sector is stagnating. Many jobs depend on the forest industry’s competitiveness and its ability to explore new markets and develop new products. These factors are fertile ground for developing technologies related to producing biochar. Both the high cost of harvesting and poor quality of forest biomass coming from harvest areas force research to focus on manufacturing high value commercial products. Gilles Brunette, Manager of the Composite Products department at FPInnovations, firmly believes that producing biochar from forest biomass will reduce fibre harvesting costs while diversifying the forest industry’s product line.

Québec in a North American market

In the province of Québec, forestry operations on public land discharge 6.5 million tons of dry biomass yearly. A very small percentage of this forest biomass is harvested and most of it is transformed into pellets for energy production. According to Statistics Canada, Québec consumes annually some 2.5 billion litres of heavy fuel oil and 541,000 tons of coal. The high calorific value of biochar produced during the project combined with the rising prices of fossil energy allow to consider replacing these two sources of energy, which would reduce Québec’s GHG emissions by about 9 million tons. On another scale, the American industry sector could potentially use an estimated 900,000 tons of activated carbon, a high value-added biochar product, every year. When passed, currently proposed American legislation on GHG emissions would be a tremendous boon for activated carbon producers.

Source : Jean-Luc Bernier, M.Sc., FPInnovations.  «Innovation through Information»,  Canadian Biomass, March/April 2012, p. 11