Study of hydrochar and process water from hydrothermal carbonization of sea lettuce

Shrestha, Ankita; Acharya, Bishnu; Farooque, Aitazaz A.

doi:10.1016/j.renene.2020.08.133

Cited by 61 publications

(33 citation statements)

References 49 publications

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“…However, when the temperature exceeds 240 °C, the degradation of organic components promotes ash to the decomposition of inorganics into water. 13 The low ash content of hydrochars can effectively avoid the deposition of the inorganic substance in the boiler and prevent scaling and corrosion, which is an advantage of hydrochar as solid fuel. Table 1 illustrates no regular between the rise of temperature and the change of the ash content.…”

Section: Resultsmentioning

confidence: 99%

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The Effect of Temperature on the Properties of Hydrochars Obtained by Hydrothermal Carbonization of Waste Camellia oleifera Shells

et al. 2021

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Hydrothermal carbonization (HTC) is a thermochemical conversion technique that can produce renewable solid biofuel by all types of waste. Waste Camellia oleifera shells (WCOSs) can be used to produce hydrochars via HTC. The effect of HTC temperature on the physicochemical properties and combustion behaviors of hydrochars was analyzed by varying from 150 to 300 °C. The mass yield of hydrochars decreased from 72.45% at 150 °C to 41.88% at 300 °C with the increase in temperature, and the higher heating value increased from 19.22 MJ/kg at 150 °C to 29.97 MJ/kg at 300 °C. The H/C and O/C values reduced from 1.30 and 0.66 of HTC150 to 0.77 and 0.27 of HTC300, respectively. Fourier transform infrared spectroscopy analysis indicated that the functional groups of hydrochar have changed because of the dehydration and decarboxylation reaction. The surface structure of hydrochars was rougher, and many pore structures were found at 240–300 °C by scanning electron microscopy analysis. The combustion behaviors of WCOSs and their hydochars are distinct via thermogravimetric analysis, and the stability of hydrochars was strengthened with the increase in HTC temperature.

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Section: Resultsmentioning

confidence: 99%

“…The results are in accordance with the literature. 13 However, some research results showed that the ash content increases with the increase in temperature. 31 …”

Section: Resultsmentioning

confidence: 99%

The Effect of Temperature on the Properties of Hydrochars Obtained by Hydrothermal Carbonization of Waste Camellia oleifera Shells

et al. 2021

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“…The spectrum of char produced at 573 K with a 10 min residence time shows bands corresponding to aliphatic and aromatic -OH (3415 cm −1 ), aromatic ring modes (1595 cm −1 and 1140 cm −1 ), carbonyl group (1684 cm −1 ), aliphatic -CH 3 (2944 cm −1 ) and CH 2 groups (1453 cm −1 ), symmetric -CH 3 stretching of the methoxyl groups (2851 cm −1 ), and symmetric -CH 3 stretching (1035 cm −1 ) and C-H in Syringyl, Guaiacyl (857 cm −1 and 807 cm −1 , respectively), as well as the nitro compounds (1353 cm −1 ) [ 28 ].…”

Section: Resultsmentioning

confidence: 99%

“…The band at 1595 cm −1 [10,16], corresponding to the aromatic ring and carbonyl group (1684 cm −1 ), seemed to be increasing drastically with the increase of operating temperature. This means the C-C and C-H bonds are consumed throughout the hydrothermal liquefaction The spectrum of char produced at 573 K with a 10 min residence time shows bands corresponding to aliphatic and aromatic -OH (3415 cm −1 ), aromatic ring modes (1595 cm −1 and 1140 cm −1 ), carbonyl group (1684 cm −1 ), aliphatic -CH 3 (2944 cm −1 ) and CH 2 groups (1453 cm −1 ), symmetric -CH 3 stretching of the methoxyl groups (2851 cm −1 ), and symmet-ric -CH 3 stretching (1035 cm −1 ) and C-H in Syringyl, Guaiacyl (857 cm −1 and 807 cm −1 , respectively), as well as the nitro compounds (1353 cm −1 ) [28].…”

Section: Ftir Analysismentioning

confidence: 99%

Characterization and Evaluation of Hydrothermal Liquefaction Char from Alkali Lignin in Subcritical Temperatures

et al. 2021

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An evaluation of hydrothermal liquefaction (HTL) char is investigated in this work. Morphological studies, N2 adsorption behavior, FTIR analysis, thermal behavior, and elemental composition are studied. The HTL char yield showed an increase with higher operating temperatures. It increased from 11.02% to 33% when the temperature increased from 573 K to 623 K. At lower temperatures, the residence time showed an impact on the yield, while close to the critical point, residence time became less impactful. Elemental analysis showed that both higher operating temperatures and longer residence times increased the nitrogen content of the chars from 0.32% to 0.51%. FTIR analysis suggested the char became more aromatic with the higher temperatures. The aliphatic groups present diminished drastically with the increasing temperature. Residence time did not show a significant impact as much as the temperature when considering the functional group elimination. An increase in operating temperatures and residence times produced thermally stable chars. HTL char produced at the lowest operating temperature and showed both the highest surface area and pore volume. When temperature and residence time increase, more polyaromatic char is produced due to carbonization.

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“…Overall, recirculation of the liquid by-products or its subsequent use for maximum energy recovery and increased systemic efficiency offers many opportunities [43]. Several studies report the composition of liquid HTC by-products [77][78][79], with many indicating potential synergies between HTC and anaerobic digestion (AD) [52,80,81] or application of the effluent in microbial fuel cells [82].…”

Section: Introductionmentioning

confidence: 99%

Cascade Membrane System for Separation of Water and Organics from Liquid By-Products of HTC of the Agricultural Digestate—Evaluation of Performance

et al. 2021

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New regulations aimed at curbing the problem of eutrophication introduce limitations for traditional ways to use the by-product of anaerobic digestion—the digestate. Hydrothermal carbonisation (HTC) can be a viable way to valorise the digestate in an energy-efficient manner and at the same time maximise the synergy in terms of recovery of water, nutrients, followed by more efficient use of the remaining carbon. Additionally, hydrothermal treatment is a feasible way to recirculate recalcitrant process residues. Recirculation to anaerobic digestion enables recovery of a significant part of chemical energy lost in HTC by organics dissolved in the liquid effluent. Recirculating back to the HTC process can enhance nutrient recovery by making process water more acidic. However, such an effect of synergy can be exploited to its full extent only when viable separation techniques are applied to separate organic by-products of HTC and water. The results presented in this study show that using cascade membrane systems (microfiltration (MF) → ultrafiltration (UF) → nanofiltration (NF)), using polymeric membranes, can facilitate such separation. The best results were obtained by conducting sequential treatment of the liquid by-product of HTC in the following membrane sequence: MF 0.2 µm → UF PES 10 → NF NPO30P, which allowed reaching COD removal efficiency of almost 60%.

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Study of hydrochar and process water from hydrothermal carbonization of sea lettuce

Cited by 61 publications

References 49 publications

The Effect of Temperature on the Properties of Hydrochars Obtained by Hydrothermal Carbonization of Waste Camellia oleifera Shells

The Effect of Temperature on the Properties of Hydrochars Obtained by Hydrothermal Carbonization of Waste Camellia oleifera Shells

Characterization and Evaluation of Hydrothermal Liquefaction Char from Alkali Lignin in Subcritical Temperatures

Cascade Membrane System for Separation of Water and Organics from Liquid By-Products of HTC of the Agricultural Digestate—Evaluation of Performance

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