426650 Valorizing Biorefinery Lignins Using Fast Pyrolysis and Electrocatalytic Upgrading

Thursday, November 12, 2015: 9:45 AM
257B (Salt Palace Convention Center)
Mahlet Garedew, Biosystems & Agricultural Engineering, Michigan State University, East Lansing, MI, Leonardo da costa Sousa, Chemical Engineering and Material Science, Great Lakes Bioenergy Center, Michigan State University, Lansing, MI, James E. Jackson, Chemistry Department, Michigan State University, East Lansing, MI and Christopher M. Saffron, Biosystems & Agricultural Engineering, Department of Forestry, Michigan State University, East Lansing, MI

Pretreatments such as extractive ammonia processing (EAP) create a lignin co-product in addition to cellulose and hemicellulose, which are fermented to ethanol in biorefineries.  As lignin comprises up to 30 wt.% of biomass and 40% of biomass’ energy, an opportunity exists for creating valuable products.  As a means to partially depolymerize lignin, biomass fast pyrolysis (BFP), uses heat (400-600°C) without oxygen to create bio-oil, biochar and combustible gas, where the major product, bio-oil, comprises 70 wt.% of the total product mass.  However, bio-oil is highly oxygenated, corrosive, low in energy content, chemically complex, and chemically reactive, making it unstable during storage and incompatible with carbon steel construction materials.  As a means of improving bio-oil properties, electrocatalytic hydrogenation (ECH) is employed to chemically reduce and deoxygenate reactive compounds.  In this study, lignin model compounds representative of bio-oil components were subjected to ECH under mild conditions (80°C and 1 atm) using ruthenium on activated carbon (Ru/ACC) as a catalytic cathode.  To date, model monomers (guaiacol, syringol, syringaldehyde, vanillin, p-cresol, creosol, eugenol, etc.) have been reduced to simpler compounds such as cyclohexanol and phenol, which have increased heating values when compared to the starting substrates. Additionally, model dimers such as 4-phenoxyphenol have been cleaved and chemically reduced to cyclohexanol and phenol.  Such an approach valorizes lignin into molecules with increased fuel value and material precursors.

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