Production of Organic Compounds through Catalyzed Hydrothermal Carbonization of Woody Biomass

Catalyzed hydrothermal carbonization of woody biomass produces hydrochar and valuable aqueous products (VAPs) that could potentially be harvested to facilitate commercialization of the process. Acetic acid, formic acid, glycolic acid, levulinic acid, 5-hydroxymethyl-2-furfural, and furfural are potential VAPs found in the process liquid. Recycling the process liquid increased the yields of VAPs not associated with hydrochar production, except for formic acid. Yields increased with the liquid:biomass ratio peaking at 10:1 for all but levulinic acid. The higher heating value of the hydrochar, 27.6 +/- 0.3 MJ/kg, was not affected by recycling or the liquid:biomass ratio. The energy yield of catalyzed hydrothermal carbonization increased from 72 to 80% when the process liquid was recycled. Energy yields for hydrochar production increased from 63 to 74% when the liquid:biomass ratio was decreased from 12:1 to 3:1.