The high moisture content of many biomass resources (e.g., aquatic biomass, sludges, food waste) makes thermochemical treatment in the presence of water (hydrothermal processing) a more attractive route than first drying and then treating. Though the field of heterogeneous catalysis developed due to commercial opportunities and environmental issues related to chemistry in the vapor phase and in organic liquids, heterogeneous catalysts can also be used to advantage under hydrothermal conditions for biomass processing. Hydrothermal catalysis has received far less attention and this talk will provide examples where this approach provides benefits for biomass processing.<br/> <br/>One example is the hydrothermal catalytic conversion (400 °C, 200 bar, 180 min) of renewable triglyceride feedstocks (algae oil, coconut oil, peanut oil, and lard) over HZSM-5 to produce aromatics, alkanes, and fuel gases. Liquid product yields of nearly 90 wt%, and yields of aromatics or around 50 wt% can be achieved. A second example is hydrothermal catalytic treatment of microalgae to reduce the metal content of the biocrude. We show that the Fe and Na content in crude bio-oil from algae HTL can be reduced over 98% via application of heterogeneous catalysts.<br/> <br/>A key challenge for using heterogeneous catalysts in hydrothermal reaction environments is the limited understanding of catalyst stability as a function of the material composition and the solvent properties. We have been conducting experiments and doing thermodynamic modeling to understand better the stability of different catalytic materials across a wide range of hydrothermal conditions and to correlate material properties with hydrothermal stability. This presentation will provide our most recent work on this topic.

Hydrothermal catalysis to valorize renewable biomass feedstocks

254th National Meeting (2017)

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