Process Improvements and Techno-Economic Feasibility of Hydrothermal Liquefaction and Pyrolysis of Biomass for Biocrude Oil Production

Suryawanshi, Pravin G.; Das, Sutapa; Borugadda, Venu Babu; Goud, Vaibhav V.; Dalai, Ajay K.

doi:10.1007/978-981-15-1804-1_10

Cited by 2 publications

(3 citation statements)

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“…As the conditions of water approach the critical point of 374 °C and 22 MPa, its properties, which include diffusivity, polarity, self-ionization, solvation power, viscosity, and surface tension, change significantly with temperature and pressure. 34,36,37 At near critical point, water behaves as a nonpolar solvent. 25 Subcritical water is able to enhance the dissociation of water at high temperatures.…”

Section: Resultsmentioning

confidence: 99%

“…During HTL of model compounds under subcritical conditions of water, water acts as a catalyst, a reactant, and a reaction medium . The presence and properties of water enhance HTL reactions such as hydrolysis, which leads to dehydration, depolymerization, decomposition, recombination, decarboxylation, and deamination reactions. ,, Under subcritical conditions of water, water behaves as an incompressible fluid and a polar solvent. As the conditions of water approach the critical point of 374 °C and 22 MPa, its properties, which include diffusivity, polarity, self-ionization, solvation power, viscosity, and surface tension, change significantly with temperature and pressure. ,, At near critical point, water behaves as a nonpolar solvent .…”

Section: Resultsmentioning

confidence: 99%

“…The presence and properties of water enhance HTL reactions such as hydrolysis, which leads to dehydration, depolymerization, decomposition, recombination, decarboxylation, and deamination reactions. ,, Under subcritical conditions of water, water behaves as an incompressible fluid and a polar solvent. As the conditions of water approach the critical point of 374 °C and 22 MPa, its properties, which include diffusivity, polarity, self-ionization, solvation power, viscosity, and surface tension, change significantly with temperature and pressure. ,, At near critical point, water behaves as a nonpolar solvent . Subcritical water is able to enhance the dissociation of water at high temperatures. , Under such elevated reaction conditions, the hydrogen bonds holding water molecules weaken and this leads to reduced dielectric constants, which increases the solubility of polar molecules in the water .…”

Section: Resultsmentioning

confidence: 99%

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Viscosity Variation of Model Compounds during Hydrothermal Liquefaction under Subcritical Conditions of Water

Edifor

Nguyen

Eyk

et al. 2021

Ind. Eng. Chem. Res.

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Recent assessments in waste-to-energy technologies highlight hydrothermal liquefaction (HTL) as a suitable process for converting organic-rich waste with high moisture content into a useful resource. Organic waste materials, including sewage sludge, food, and agricultural waste residues, typically contain lipids, carbohydrates, proteins, and lignin with varying compositions depending on their origin. Fluid properties of reacting HTL slurries under subcritical water conditions, particularly viscosity and density, affect material flow and heat transfer in both batch and continuous HTL process systems. Real-time viscosity variations of 20 wt % water slurries of model compounds, sunflower oil, sucrose, and soy protein were determined in a stirred tank batch reactor using the Metzner−Otto method. Measured torque on the impeller shaft at a fixed impeller speed was used to determine the changes in the viscosity of the reacting slurry at different reaction temperatures. Changes in the viscosity of the sunflower oil mixture were insignificant as compared to viscosity variations with sugar-and soy protein-derived feedstock. The viscosity of the soy protein solution decreased rapidly with the temperature during hydrolysis of polypeptides into amino acids between 25 and 100 °C. Further increase in the temperature led to minimal changes in viscosity as more soluble compounds were produced above 100 °C. The viscosity of the sucrose solution changed significantly above 250 °C when carbon compounds precipitated from the solution. Viscosity variations of mixtures of model compounds were determined to predict viscosity changes in biomass.

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