Upgrading agricultural wastes using three different carbonization methods: Thermal, hydrothermal and vapothermal

Yeoh, Keat-Hor; Shafie, Shafida Azwina Mohd; Al-attab, K.A.; Zainal, Zulkarnain

doi:10.1016/j.biortech.2018.06.024

Cited by 24 publications

(24 citation statements)

References 30 publications

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“…However, VTC produced higher solid yields and, therefore, higher energy yields than HTC for both feedstocks. In contrast, Shafie et al and Yeoh et al reported mostly lower solid yields and higher HHV from the VTC process compared to HTC process (both at 220 • C, 1 h; two feedstocks [10,14], three feedstocks [14]). Again, as in [11], the combination of these two trends in the energy yield showed that the VTC process was more efficient for energy yield.…”

Section: Introductionmentioning

confidence: 88%

“…In this case, the hydrochar made from HTC should be more stable in the environment than that made from VTC, which would have consequences for its use, e.g., as a soil amendment. On the other hand, comparisons between hydrochars from HTC vs. VTC for use as fuels have produced mixed results on how the phase of the reaction medium affects the important energy parameters: solid yield, higher heating value (HHV) and energy yield [10,11,14]. Comparing HTC vs. VTC for two feedstocks, digestate and straw, at 230 • C, 6 h, Funke et al [11] found no clear trend in HHV: VTC-chars had a higher HHV than HTC-chars from digestate, but for straw, the order was reversed.…”

Section: Introductionmentioning

confidence: 99%

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Comparative Studies on Water- and Vapor-Based Hydrothermal Carbonization: Process Analysis

Ro¹,

Libra

Álvarez-Murillo

2020

Energies

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Hydrothermal carbonization (HTC) reactor systems used to convert wet organic wastes into value-added hydrochar are generally classified in the literature as liquid water-based (HTC) or vapor-based (VTC). However, the distinction between the two is often ambiguous. In this paper, we present a methodological approach to analyze process conditions for hydrothermal systems. First, we theoretically developed models for predicting reactor pressure, volume fraction of liquid water and water distribution between phases as a function of temperature. The reactor pressure model predicted the measured pressure reasonably well. We also demonstrated the importance of predicting the condition at which the reactor system enters the subcooled compression liquid region to avoid the danger of explosion. To help understand water–feedstock interactions, we defined a new solid content parameter %S(T) based on the liquid water in physical contact with feedstock, which changes with temperature due to changes in the water distribution. Using these models, we then compared the process conditions of seven different HTC/VTC cases reported in the literature. This study illustrates that a large range of conditions need to be considered before applying the label VTC or HTC. These tools can help in designing experiments to compare systems and understand results in future HTC research.

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Section: Introductionmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Comparative Studies on Water- and Vapor-Based Hydrothermal Carbonization: Process Analysis

Ro¹,

Libra

Álvarez-Murillo

2020

Energies

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“…Infolge der hydrothermalen Atmosphäre, bei der die HTC abläuft, werden hier bevorzugt feuchte bis sehr nasse Biomassen eingesetzt, z. Die Kohlenstoffverluste durch den in der Flüssigphase gelösten Kohlenstoff sind bei der VTC jedoch deutlich geringer als bei der HTC, was zu einer insgesamt höheren Energieausbeute führen kann [52,53]. Diese müssen vor Beginn des Prozesses aus ver- [51].…”

Section: Hydrothermale Carbonisierungunclassified

“…B. eine stärkere Entgasung (pyrolytische Zersetzung) statt, was in vergleichsweise höheren Masseverlusten resultiert. Die Kohlenstoffverluste durch den in der Flüssigphase gelösten Kohlenstoff sind bei der VTC jedoch deutlich geringer als bei der HTC, was zu einer insgesamt höheren Energieausbeute führen kann , . Auch weisen die Produkte der VTC durchschnittlich einen höheren Aschegehalt auf , da hier im Vergleich zur HTC keine anorganischen Stoffe ausgewaschen werden.…”

Section: Vorbehandlungsoptionenunclassified

Wärmeinduzierte Vorbehandlung lignocellulosehaltiger Biomassen – Prozesse, Verfahren und deren Einordnung

Scherzinger

Kulbeik

Grumbrecht

et al. 2019

Chemie Ingenieur Technik

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Im Folgenden werden verschiedene Verfahren einer wärmeinduzierten Vorbehandlung lignocellulosehaltiger Biomassen zur Erzeugung von Festbrennstoffen beschrieben. Dabei wird auch auf die in der Biomasse auf molekularer Ebene ablaufenden Veränderungen eingegangen. Die beschriebenen Verfahren (Torrefizierung, hydrothermale Carbonisierung, vapothermale Carbonisierung und Autoklavierung) laufen bis zu einem Temperaturniveau von 300°C ab. Abschließend erfolgt eine Einordnung dieser Verfahren zur Einschätzung der spezifischen Vor-und Nachteile.In the following, different techniques for a heat-induced pretreatment of lignocellulosic biomass for the production of solid fuels are described. Thereby, also changes at the molecular level of the biomass are discussed. The discussed techniques (torrefaction, hydrothermal carbonization, vapothermal carbonization, and autoclaving) proceed in a temperature range up to 300°C. Finally, a classification of the different techniques takes place to evaluate the specific advantages and disadvantages.

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“…Various plants or trees including orange peel [5], pine [6], and bamboo [7] as source materials may be hydrothermally carbonized to generate hydrochar or nanocarbon. There are also reports on waste management using the hydrothermal carbonization approach to dispose urban sludge [8,9], spent wine [10], food waste [11][12][13][14], and agricultural residues [15][16][17][18]. The kinetics of hydrothermal carbonization has been investigated to determine the reaction rate [19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Dye Adsorption and Electrical Property of Oxide-Loaded Carbon Fiber Made by Electrospinning and Hydrothermal Treatment

Kansara

Patel

Gan

et al. 2019

Fibers

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Our current study deals with the dye adsorption and electrical property of a partially carbonized composite fiber containing transition metal oxides including, iron oxide, nickel oxide, and titanium oxide. The fiber was made by electrospinning, carbonization, and hydrothermal treatment. During the electrospinning, titanium oxide particles were dispersed in polyacrylonitrile (PAN) polymer-dimethylformamide (DMF) solution. Nickel chloride and iron nitrate were added into the solution to generate nickel oxide and iron oxide in the subsequent heat treatment processes. The polymer fiber was oxidized first at an elevated temperature of 250 °C to stabilize the structure of PAN. Then, we performed higher temperature heat treatment at 500 °C in a furnace with hydrogen gas protection to partially carbonize the polymer fiber. After that, the oxide-containing fiber was coated with activated carbon in a diluted sugar solution via hydrothermal carbonization at 200 °C for 8 h. The pressure reached 1.45 MPa in the reaction chamber. The obtained product was tested in view of the dye, Rhodamine B, adsorption using a Vis-UV spectrometer. Electrical property characterization was performed using an electrochemical work station. It was found that the hydrothermally treated oxide-containing fiber demonstrated obvious dye adsorption behavior. The visible light absorption intensity of the Rhodamine B dye decreased with the increase in the soaking time of the fiber in the dye solution. The impedance of the fiber was increased due to the hydrothermal carbonization treatment. We also found that charge build-up was faster at the surface of the specimen without the hydrothermally treated carbon layer. Electricity generation under visible light excitation is more intensive at the hydrothermally treated fiber than at the one without the hydrothermal treatment. This result is consistent with that obtained from the dye adsorption/decomposition test because the charge generation is more efficient at the surface of the hydrothermally treated fiber, which allows the dye to be decomposed faster by the treated fibers with activated carbon.

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Upgrading agricultural wastes using three different carbonization methods: Thermal, hydrothermal and vapothermal

Cited by 24 publications

References 30 publications

Comparative Studies on Water- and Vapor-Based Hydrothermal Carbonization: Process Analysis

Comparative Studies on Water- and Vapor-Based Hydrothermal Carbonization: Process Analysis

Wärmeinduzierte Vorbehandlung lignocellulosehaltiger Biomassen – Prozesse, Verfahren und deren Einordnung

Dye Adsorption and Electrical Property of Oxide-Loaded Carbon Fiber Made by Electrospinning and Hydrothermal Treatment

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