Products and Kinetics for Isothermal Hydrothermal Liquefaction of Soy Protein Concentrate

Abstract

Soy protein concentrate was hydrothermally treated at isothermal temperatures of 200, 250, 300, and 350 °C for times up to 60 min to produce a crude bio-oil. Additional product fractions included water-soluble products, gases, and residual solids. We report herein the conversion of protein and gravimetric yields of the different product fractions. The biocrude yield generally increased with both time and temperature as did the yield of gaseous products. The highest biocrude yield was 34%, produced from liquefaction at 350 °C for 60 min. Chemical and physical characterization of the biocrude revealed how its composition and boiling point range changed with reaction time. Finally, we report a reaction network and the parameters for a phenomenological kinetics model that captures the influence of time and temperature on the yields of gas, solid, biocrude, and aqueous-phase products from isothermal hydrothermal liquefaction (HTL) of soy protein concentrate. The reaction network comprised a sole primary path, which converted soy protein concentrate to aqueous-phase products. Secondary reactions of these water-soluble compounds produced biocrude and gases. There was no direct path to biocrude formation from the biomass feedstock.

Pathways and Kinetics for Autocatalytic Reduction of CO2 into Formic Acid with Fe under Hydrothermal Conditions

“…Mathematica 10.2 was employed to solve the system of ordinary differential equations and simultaneously estimate the A i (Arrhenius pre-exponential factors) and E i (activation energies) of hydrothermal HCO 3 – reduction by minimizing the sum of squared residuals (SSR) as eq 1 . 30 …”

Hydrothermal Liquefaction of Model Food Waste Biomolecules and Ternary Mixtures under Isothermal and Fast Conditions

“…The energy recoveries in this study for casein are consistent with prior reports on isothermal HTL of crude algal protein, soya protein, egg albumin, and bovine serum albumin (calculated based on reported elemental compositions) where energy recoveries were 11.7%–30.5%. Luo et al and Teri et al, on the other hand, produced biocrude with 60.6% and 54.7% (calculated based on reported elemental compositions) energy recovery from soy protein concentrate and soy protein, respectively, under similar isothermal reaction conditions, and Sheehan et al achieved high energy recoveries of 65% after fast HTL of soy protein isolate . The higher energy recoveries from soy protein concentrate and soy protein isolate are a direct result of the higher biocrude yields reported for these proteins.…”

“…These values for the nitrogen recovery in the aqueous phase are within the range of those reported previously. Luo et al observed ∼50% N recovery from isothermal HTL of soy protein concentrate at 200–350 °C for 10 min . Valdez et al reported ∼75% N distribution in the aqueous phase from isothermal HTL of microalgae over a range of reaction conditions (250–400 °C, 10–90 min) .…”

Synergistic and Antagonistic Interactions during Hydrothermal Liquefaction of Soybean Oil, Soy Protein, Cellulose, Xylose, and Lignin

“…These values are similar to the biocrude yields reported from HTL of castor oil (∼85%), sunflower oil (∼85%), casein (∼20%), and soy protein (∼25%) at similar conditions. 3,5,20 The biocrude yields from HTL of the lignocellulose model compounds are much lower. They are 4.6, 6.6, and 1.4 wt % for cellulose, xylose, and lignin, respectively.…”