As the demand for renewable energy increases, researchers and industry alike are turning to pyrolysis for extracting biofuels from biomass. Bio-oils generated through pyrolysis are generally limited by poor stability, high acidity, high viscosity, and low energy density, in part due to their high oxygen content. Methods to upgrade through post-processing are a costly solution, however in situ upgrading could provide a more economical alternative. Inexpensive clay minerals show promise as effective catalysts for in situ upgrading and are economically advantageous over traditional catalysts due to their widespread abundance and relatively low cost. This study examines the effects of various biomasses co-pyrolyzed with inexpensive clay minerals to promote higher quality bio-oils and larger yields of pyrolysis gas. Co-pyrolysis with pure cellulose and clay minerals demonstrates improved deoxygenation, however the exact pathways are not well understood. In this work, lignin, cellulose, and representative hemicellulosic compounds were co-pyrolyzed with bentonite, montmorillonite, kaolin, and dolomite to determine the extent of deoxygenation and to catalogue the resulting condensable and non-condensable pyrolysis products generated. The incorporation of such clay minerals creates a more stable liquid bio-oil and enhanced pyrolysis gas yields of H2, CH4, C2H2, C2H4, and C2H6, likely due to deoxygenation reactions. Additionally, the resulting mineral-impregnated biochar demonstrates an improved adsorption capacity over pure biochar. Uptake of methylene blue from water increased significantly in biomasses co-pyrolyzed with bentonite, kaolin and montmorillonite, resulting in a potential value-added secondary product.

Promoting deoxygenation in lignocellulosic biomass: Co-pyrolysis with clay minerals as in situ catalysts

2019 Fall National Meeting

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