1,720,978 research outputs found
Coupling biomass hydrothermal carbonization and green solvent extraction
Full text linkThis paper merges two leading-edge practices of sustainable waste valorization chains – biomass hydrothermal carbonization (HTC) and green solvent extraction – into an integrated process scheme. The innovation is to intersperse two hydrothermal carbonization steps with solvent extraction to recover valuable products from the reaction process water before completing the carbonization. The study uses rice husk as the waste biomass, hydrophobic deep eutectic decanoic acid/thymol (DES) as the green solvent, and furfural and 5-hydroxymethylfurfural as the target chemicals. HTC went batch-wise (230 °C, 1/4 solid/liquid ratio, total reaction time 2 h). DES extraction recovered up to 91 % of the chemicals from the process water. Although only 2 % of the original biomass converts to platform chemicals, the process illustrates a new methodology that is tailorable for other optimized productions. A flowsheet scheme helps quantify mass balances. The many degrees of freedom in the operational parameters allow for the intensification of the industrial-scale process. The new method paves the way for further developments, applying the combined process to other biomasses, solvents, and target chemicals
Fractal Kinetic Analysis of Biomass Hydrothermal Carbonization
Full text linkThis paper introduces fractal analysis to study the kinetics of biomass hydrothermal carbonization. The reacting water-biomass slurry is a complex system leading to hydrochar by microscale reactions constrained into fractal topological boundaries. Literature and purpose experimental data check equations adapted from the fractal-like repertoire. More general models are derived from a shortcut, stochastic-based formalism, avoiding the mathematical sophistication of fractal calculus. Fractal equations explain observed data better and with fewer parameters than traditional mass-action network models (0.91202 < R (2) < 0.99998, average 0.97957) over a wide range of biomass and operational conditions. Exploratory experiments highlight the surface fractal dimension of hydrocars and their variation concerning that of parent biomasses (from 2.00 to 2.84). The confluence of fitting success and evidence of HC fractality encourages prosecuting research for making fractal kinetics a fully fledged tool of hydrothermal carbonization studies
Supercritical Water Technology Applied to the Purification of Waters Contaminated by Toxic Micro-Polluting Organic Compounds
No full text"Purification of water contaminated by toxic organic compounds at low and very low concentration is a quite interesting challenge from both the technical and the economical point of view. In fact, the direct destruction of organic com-pounds dissolved in very diluted aqueous solution is very costly and hardly achievable. To overcome this problems it was studied and developed a new water purification process which is made of three steps: 1) removal of the diluted and toxic polluting compounds by adsorption on activated carbon beds operating at ambient P ant T; 2) regeneration of the exhausted carbon bed with supercritical water in order to obtain a mixture of water and polluting compounds signifi-cantly more concentrated than the contaminated liquid water; 3) destruction of the toxic compounds in a continuous Supercritical Water Oxidation Reactor. Step 1) was studied at laboratory scale in order to obtain all the required infor-mation for modeling the adsorption operation; step 2) was modeled by using literature experimental data and, step 3) was validated at pilot plant scale. In all the above mentioned steps, phenol was used as representative of polluting com-pounds.
Development and Evaluation of a New Advanced Solid Bio-Fuel and Related Production Process
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Experimental and calculated breakthrough behavior in water purification by fixed bed activated carbon
No full textProduction of Red Wine Polyphenols as Ingredient for the Food and Pharmaceutical Industry
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Modeling biomass hydrothermal carbonization by the maximum information entropy criterion
No full textThis paper demonstrates an innovation in the kinetic modeling of biomass hydrothermal carbonization
based on stochastic techniques. The dynamics of HTC solid-phase transformations is described without
assuming a reaction network. Through the maximum-entropy principle, an equation, which fits data
flexibly, rises to the status of a lumped kinetic model. The time-course of biomass conversion is described
as the macroscopic effect of microreactions, whose frequency is distributed as a continuous
probability density function. The mathematics which defines the density function takes advantage of
the identified analogies with other scientific fields. The corresponding cumulative frequency distribution is
shown to coincide with the empirical fitting equation. The analysis of a wide range of literature data,
concerning various waste biomasses, allows testing the new model. The good accordance between
previsions and experimental evidence encourages the research to follow this way. Sound procedures for
further validating the model are outlined
Identification of an Optimal Set of Parameters for the Process of Pasteurization of Beverages by Using Dense Gases
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