(721b) Hydrothermal Liquefaction of Model Polysaccharides and Polysaccharide-Rich Food-Processing Waste

Authors: 
Gollakota, A., The Pennsylvania State University
Savage, P. E., The Pennsylvania State University
Padash, A., The Pennsylvania State University
Kaplan, J., The Pennsylvania State University
Hydrothermal liquefaction (HTL) is the thermochemical conversion of wet biomass (e.g., food waste, waste from food processing industries) in hot compressed water into energy-dense biocrude, a biofuel precursor. This process is especially attractive for wet biomass as it obviates the drying step required in other biomass conversion processes (e.g., pyrolysis). The main biochemical constituents of food waste are proteins, polysaccharides, and lipids, and the biocrude yields from HTL can be correlated with and predicted from its biochemical content. Previous studies with HTL of model biomass compounds revealed that polysaccharide is the most recalcitrant biochemical constituent to obtain biocrude3-5.

Conventional HTL of various agricultural and food processing wastes has been studied extensively under subcritical temperatures isothermally for long holding times1-2. Fast HTL, a recent variation of this technology involves rapid non-isothermal heating and short reaction times (~1 min) and has achieved higher biocrude yields than conventional HTL for a variety of whole biomass6-11 and a few proteins12-13.

Here we will focus on fast and isothermal HTL at different biomass loadings of model polysaccharides (chitin, pectin, potato starch), and processing waste obtained from a potato flake production plant. Using knowledge of the structure of and components in the model polysaccharide and temporal variation of the reaction products, we can posit reaction pathways and determine the reaction kinetics. Such information will provide new knowledge about the hydrothermal chemistry of polysaccharides that have received scant attention despite their abundance in food waste. We will further use the results from model polysaccharides to interpret the HTL reaction pathways of the potato flake processing waste. These results can facilitate the assessment of the potential of HTL for producing bio-fuel precursors from any polysaccharide-containing food/food-processing waste.

References:

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