MOST- Novel microwave fluidized bed reactor for catalytic pyrolysis of biomass residues and biochar applications

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There are estimated 30 million tonnes of forest residues available each year at British Columbia, which can be converted to high-value liquid biofuels or biochemicals to offset the high cost associated with collection and pretreatment. Pyrolysis is a thermal cracking process of biomass in the absence of oxygen, which converts biomass to bio-oil and biochar. Bio-oil can be further upgraded to liquid fuels. Pyrolysis has been identified as a promising pathway for converting biomass residues to biofuels (diesel and jet fuel) and biochemicals (e.g. carbon, alcohols). The low quality of bio-oil and biochar, however, imposes challenges in upgrading and application. Specifically, the high oxygen content in bio-oil consumes large amount hydrogen in upgrading operation, which accounts for more than 66% of total greenhouse gas emissions over the whole liquid biofuel supply chain associated with hydrogen production from fossil fuels. The poor quality of biochar also surrenders its use as fertilizer for soil applications and as a reducing agent in metallurgical processes.In this Canada-Taiwan collaborative project, we will develop a novel microwave fluidized bed reactor and low-cost natural catalysts to in-situ pyrolyze biomass to bio-oil and biochar. Due to the unique internal microwave heating of biomass particles, and in-situ microwave-assisted catalytic cracking of organic vapours on hot catalyst surface, bio-oil quality can be improved significantly, as reflected by low oxygen content, low acidity and viscosity in our preliminary tests. Due to the internal rapid heating, the biochar particles of much porous structure and thus high specific surface area are created, which in conjunction with remaining natural catalysts as nutrients serve as a high-value carbon-based fertilizer with high water and nutrient holding capacity. The novel catalytic reactor system to be developed will convert abundant biomass residues to high-quality bio-oil and biochar, contributing to the Canadian bioeconomy, and contribute to meeting the national greenhouse emission reduction target.