Study on combustion performance of hydrothermally dewatered lignite by thermal analysis technique

Mo, Qiong; Liao, Junjie; Chang, Liping; Yong, Han; Chaffee, Alan L.; Wang, Bao

doi:10.1016/j.fuel.2020.119217

Cited by 24 publications

(16 citation statements)

References 36 publications

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“…According to the results of bond order analysis, C–O and C–C bonds were divided into four categories: MBOs of Ph(CO)O–CH 3 and CH 3 –OC(O)OH were the lowest and their corresponding BDE values also belong to the smallest category, which are 88.94 and 89.32 kcal/mol, respectively. This may be due to the polarity between C–O bonds and the fracture trend is more obvious in the HTC process, which can verify that HTC has the function of removing the volatile matter MBOs of the C–O bonds were greater than 1, and their BDE values were greater than 100 kcal/mol.…”

Section: Resultsmentioning

confidence: 78%

“…MBOs of Ph(CO)O–CH 3 and CH 3 –OC(O)OH were the lowest and their corresponding BDE values also belong to the smallest category, which are 88.94 and 89.32 kcal/mol, respectively. This may be due to the polarity between C–O bonds and the fracture trend is more obvious in the HTC process, which can verify that HTC has the function of removing the volatile matter …”

Section: Resultsmentioning

confidence: 80%

See 1 more Smart Citation

Study on Chemical Bond Dissociation and the Removal of Oxygen-Containing Functional Groups of Low-Rank Coal during Hydrothermal Carbonization: DFT Calculations

Dang

Wang

et al. 2021

ACS Omega

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The molecular structure model of lignite was constructed, and the dissociation and removal mechanism of different C–O bonds and oxygen-containing functional groups was investigated using density functional theory (DFT) calculations. First, the bond order and bond dissociation enthalpy (BDE) were analyzed to predict the strength of different chemical bonds, and differences in the BDE and bond order were related to the difference in the fragment structure and electronic effects. The first group to break during hydrothermal carbonization (HTC) is the methyl of Ph(CO)O–CH3, followed by the C–O of CH3–OC(O)OH; the hydroxyl in Ph–OH is the most thermally stable group, followed by the hydroxyl in CH3OC(O)–OH. In addition, the orbital localization analysis has also been carried out. All three chemical bonds of Ph(CO)OCH3 show the characteristics of σ bond, while Ph(CO)OCH3 and Ph(CO)–OCH3 with the Mayer bond order (MBO) greater than 1 also contains certain π bond characteristics. The lignite van der Waals (vdW) surface electrostatic potential (ESP) was constructed and visualized, and the results showed that the oxygen-containing functional groups mainly contributed to the area with a large absolute ESP. Finally, weak interactions between water molecules and lignite at different sites were described by independent gradient model (IGM) analysis. Models A, B, and E formed weak interactions with the hydrogen bond as the main force; model E showed the weakest hydrogen bond, while model C showed van der Waals interaction as the dominant force. In addition, some steric effect was also observed in model D.

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Section: Resultsmentioning

confidence: 78%

Section: Resultsmentioning

confidence: 80%

Study on Chemical Bond Dissociation and the Removal of Oxygen-Containing Functional Groups of Low-Rank Coal during Hydrothermal Carbonization: DFT Calculations

Dang

Wang

et al. 2021

ACS Omega

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“…Combustion characteristics of raw lignite and the corresponding hydrochar were studied by thermogravimetry coupled with differential scanning calorimetry (TG-DSC) by heating the sample from room temperature to 700 °C under atmospheric air [ 90 ]. The activation energy of the hydrochar samples increased with temperature increasing at char combustion stage.…”

Section: Hydrothermal Carbonization Of Food Waste For Char Productionmentioning

confidence: 99%

Hydrothermal Conversion of Food Waste to Carbonaceous Solid Fuel—A Review of Recent Developments

Khan

Hameed

Siddiqui

et al. 2022

Foods

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This review critically discussed recent developments in hydrothermal carbonization (HTC) of food waste and its valorization to solid fuel. Food waste properties and fundamentals of the HTC reactor were also covered. The review further discussed the effect of temperature, contact time, pressure, water–biomass ratio, and heating rate on the HTC of food waste on the physiochemical properties of hydrochar. Literature review of the properties of the hydrochar produced from food waste in different studies shows that it possesses elemental, proximate, and energy properties that are comparable to sub-bituminous coal and may be used directly as fuel or co-combusted with coal. This work conclusively identified the existing research gaps and provided recommendation for future investigations.

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“…17,18 Hydrothermal dewatering (HD) attracted extensive attention because it could filter out water-soluble inorganic material and irreversibly remove the moisture from lignite. [19][20][21][22] Since moisture was removed as liquid form, the energy consumption of HD coupled with mechanical expression was only about 40% of that of evaporation drying method. 23 The studies focused on HD method showed that the dehydration efficiency could achieve 66.71%-80.59%.…”

Section: Introductionmentioning

confidence: 99%

“…36 The reduction of carboxyl and hydroxyl content effectively inhibited the hydrophilicity of lignite. 21,22 Meanwhile, the physicochemical structure of lignite upgraded by DES-assisted HD (DES-HD) was changed greatly. Therefore, it was of great significance to study the combustion performance of lignite upgraded by DES-HD.…”

Section: Introductionmentioning

confidence: 99%

Combustion performance of lignite after efficient upgrading via deep eutectic solvent‐assisted hydrothermal dewatering

Huang

et al. 2023

Asia-Pacific J Chem Eng

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In order to increase the efficiency of hydrothermal dewatering (HD), a deep eutectic solvent (DES, synthesized by ChCl and ZnCl2) was employed to promote the removal of moisture and oxygen from lignite. The variation of physicochemical structure of upgraded coals greatly affected the combustion performance. The effects of addition amount of DES, upgrading temperature, and the molar ratio by ChCl and ZnCl2 on combustion performance of upgraded coals were analyzed via thermogravimetric analysis. Compared with HD lignite upgraded at 280°C, the combustion curves of DES‐HD lignite were shifted and delayed toward a higher temperature zone as DES additions increased. DES‐HD lignite had lower spontaneous combustion tendency and higher combustion reactivity. When upgrading temperature increased from 250 to 300°C, the combustion curves of lignite upgraded with 3.0‐g DES (ChCl:ZnCl2 = 1:1) first moved to the low‐temperature zone and then shifted to the high‐temperature zone. DES‐HD lignite maintained the advantages of raw coal in terms of combustion characteristics. For lignite upgraded with different molar ratios of ZnCl2 in DES, the difference in combustion behavior was mainly manifested in the burnout stage. The burnout stage was advanced slightly as the molar ratio of ZnCl2 increased.

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Study on combustion performance of hydrothermally dewatered lignite by thermal analysis technique

Cited by 24 publications

References 36 publications

Study on Chemical Bond Dissociation and the Removal of Oxygen-Containing Functional Groups of Low-Rank Coal during Hydrothermal Carbonization: DFT Calculations

Study on Chemical Bond Dissociation and the Removal of Oxygen-Containing Functional Groups of Low-Rank Coal during Hydrothermal Carbonization: DFT Calculations

Hydrothermal Conversion of Food Waste to Carbonaceous Solid Fuel—A Review of Recent Developments

Combustion performance of lignite after efficient upgrading via deep eutectic solvent‐assisted hydrothermal dewatering

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