The elucidation of reaction kinetics for hydrothermal liquefaction of model macromolecules

Obeid, Reem; Lewis, David M.; Smith, Neil; Eyk, Philip J. van

doi:10.1016/j.cej.2019.03.240

Cited by 45 publications

(34 citation statements)

References 39 publications

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“…Organic yields of renewable crude like oil were >90% at reaction temperatures between 200 and 350 °C, which agreed with other investigations on HTL of sunflower oil/water mixtures. , According to the material balance in the Supporting Information, the change in mass percentage of crude like oil over the total mass of products from 200 to 300 °C was almost insignificant (0.3%) as the apparent viscosity of the reacting slurry decreases by 0.06 Pa·s within the same temperature range. This implies that a small change in crude like oil yields resulting from the degradation and recombination of certain compounds in addition to the minimal changes in the product mass contributes to the variations in the apparent viscosity of the reacting slurry.…”

Section: Resultssupporting

confidence: 89%

“…During heating, the interaction of the aqueous and oil phase results in the production of gas under different reaction conditions. According to the reaction pathway proposed by Obeid et al, HTL lipid feedstock reacts to produce renewable crude like oil and soluble compounds in the aqueous products that degrade and recombine to form other products in the aqueous and crude like oil phase, respectively, under different reaction conditions. The gas products result from decarboxylation of the renewable crude like oil phase.…”

Section: Resultsmentioning

confidence: 99%

“…From the data shown in Figure , the apparent viscosity of the soy protein/water mixture decreases by 2.3 Pa·s from room temperature to 160 °C (48 bar) and changes insignificantly (±0.05 Pa·s) when the temperature and pressure increase from 160 °C at 48 bar to 350 °C at 200 bar. Between 25 and 100 °C, polypeptides in protein hydrolyze to produce amino acids, which dissolve in the aqueous phase . HTL reactions of proteins include decomposition, decarboxylation, deamination, dehydration, deoxygenation, deamination, denitrogenation, and decomposition reactions that break down complex protein bonds into peptides and amino acids. , When heat is applied to pressurized HTL protein feedstock, the van der Waal forces holding the protein bonds break apart, thereby decreasing the bond energy and reducing the amount of force required to agitate the fluid.…”

Section: Resultsmentioning

confidence: 99%

“…The macromolecules in biomass comprise lipids, proteins, carbohydrates, and lignin in different variations and proportions. , Under HTL conditions, the elevated temperatures and pressures greatly influence the transformation of these macromolecules into different intermediate and final products. The presence and composition of each organic macromolecule in biomass additionally affect the properties of the products produced during HTL …”

Section: Introductionmentioning

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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Section: Resultssupporting

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

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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“…Measured total biocrude yields in this study ranged from 18.97 to 26.53%, in agreement with previous studies. 18,28,37,45,46 The DW fraction contained the highest yield, followed by the DL and EL fractions for all experimental conditions. The quadratic model for biocrude yield had a good fit without overfitting the data (R 2 (pred.)…”

Section: ■ Results and Discussionmentioning

confidence: 93%

Hydrothermal Liquefaction of Acid Whey: Effect of Feedstock Properties and Process Conditions on Energy and Nutrient Recovery

Sudibyo

Wang

Tester

2021

ACS Sustainable Chem. Eng.

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Improper management of dairy wastewater (acid whey) leads to water basin eutrophication and greenhouse gas emissions. We evaluated hydrothermal liquefaction as a means to sustainably manage and valorize acid whey wastes by converting them into biocrude oil and recovering nutrients in aqueous-phase byproducts. In a set of well-defined experiments, we studied the effects of reaction temperatures (280−360 °C), reaction times (7.5−37.5 min), feedstock pH values (2.5−8.5), and feedstock salt contents (0−2 wt %) on the energy recovered and the yields of products and elements. Response surface analysis showed that an alkaline feedstock pH (8.5) and a short reaction time (7.5 min) combined with a specific optimal reaction temperature for certain salt content in the feedstock were required to maximize biocrude energy recovery and nutrient recovery for a range of feedstock compositions. In general, 280−290 °C was optimal for salt contents ≤1.675 wt % and 360 °C for salt contents 1.675−2 wt %. Carbon and nitrogen were mostly distributed between biocrude and aqueous-phase products, added with distribution to the gas phase at higher temperatures. Partitioning of inorganics, for example, calcium and phosphorus, into aqueous-phase and solid hydrochar products depended on reaction conditions. This study provides new information for controlling target product composition as well as specifying desirable operating conditions for practical systems.

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Nitrogen distribution in the products from the hydrothermal liquefaction of Chlorella sp. and Spirulina sp.

Bao

Shao

Zhang

et al. 2022

Front. Chem. Sci. Eng.

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The elucidation of reaction kinetics for hydrothermal liquefaction of model macromolecules

Cited by 45 publications

References 39 publications

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

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

Hydrothermal Liquefaction of Acid Whey: Effect of Feedstock Properties and Process Conditions on Energy and Nutrient Recovery

Nitrogen distribution in the products from the hydrothermal liquefaction of Chlorella sp. and Spirulina sp.

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