Influence of different state alkali and alkaline earth metal on chemical structure of Zhundong coal char pyrolyzed at elevated pressures

Xie, Xiaochen; Liu, Li; Lin, Dan; Zhao, Yan; Qiu, P

doi:10.1016/j.fuel.2019.115691

Cited by 41 publications

(5 citation statements)

References 44 publications

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“…The increase of C–O, CO, and C–H structures on the char surface was promoted. Generally, the more disordered the carbon structure, the more reactive it is. , The reaction between C–H 2 O and C–CO 2 promotes the loading of C–O and CO onto the char surface, but at the same time, a small amount is shed/consumed and the final total amount is increased. The proportion of O-containing groups increases to 33.828% (Ia 3 ), and the proportion of alkyl complexes increases to 19.597% (Ib 3 ), which, in turn, enhances the disordered nature of the char surface structure.…”

Section: Resultsmentioning

confidence: 99%

Mechanism of CO₂ and H₂O Action on Char in Oxy-fuel Combustion with Wet Flue Gas Recirculation

Feng

Sun

et al. 2023

Energy Fuels

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The mechanism of the combined action of the C–CO2 and C–H2O reactions has yet to be clarified in the study of oxy-fuel combustion with wet flue gas recirculation (WFGR). The ultrahigh temperature (1573 K) and atmosphere of an industrial boiler are simulated in the flat flame burner reaction system (FFB-RS). The measurement of surface reactive groups and combustion reactivity of char uses Fourier transform infrared spectroscopy (FTIR) and a microfluidized bed reaction analyzer (MFBRA). The results show that char combustion reactivity has an excellent positive correlation with an O-containing reactive group. Above a 35% H2O concentration, its physical properties dominate, while below 35%, its chemical properties play a significant role. When the ratio of H2O/CO2 is close to 1, there is a synergistic relationship between the C–CO2 and C–H2O reactions, which did not occupy the same active sites, promoting the formation of O-containing reactive groups (33.83%) and alkyl complexes (19.6%) with a combustion reaction rate of 0.225%/s.

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Section: Resultsmentioning

confidence: 99%

Mechanism of CO₂ and H₂O Action on Char in Oxy-fuel Combustion with Wet Flue Gas Recirculation

Feng

Sun

et al. 2023

Energy Fuels

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“…Four wavenumber zones of 3100–2800, 1760–1487, 1487–1000, and 920–700 cm –1 were selected in this study, which were assigned to aliphatic and aromatic C–H, CO and aromatic CC, C–O (also including −CH 3 and Si–O), and aromatic C–H, respectively, according to the approach described in refs − . All of the spectra of biochars were thus deconvoluted, and an example of the deconvoluted spectrum for the 500AC sample is also shown in Figure .…”

Section: Resultsmentioning

confidence: 99%

Changes in Biochar Functional Groups and Its Reactivity after Volatile–Char Interactions during Biomass Pyrolysis

Liu

Lin

et al. 2020

Energy Fuels

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In this study, biochars prepared under 500−900 °C interacted with cellulose volatiles at 500 °C, and the effects of volatile−char interactions on the changes of biochar functional groups and its reactivity were investigated. The Fourier transform infrared (FTIR) spectrum deconvolution method was introduced to semiquantitatively evaluate the changes in the functional groups, and the reactivity of biochar was characterized with thermogravimetry as well. The results indicated that the surface functional groups varied significantly for the biochars prepared under different temperatures, and the changing trend in biochar functional groups during volatile−char interactions also differed. The active surface functional groups of the lower-temperature biochar including the carboxyl and aliphatic C−H groups were largely consumed, while the surface of the higher-temperature biochar might absorb/deposit the infrared-active coke precursors. The reactivity of biochar decreased after volatile−char interactions due to the consumption of active functional groups and the dehydrogenation condensation of biochar during the interactions. The combustion reactivity of biochar was in positive correlation to the biochar activity during volatile−char interactions. The lowertemperature biochar with higher combustion reactivity was found to be more active during the volatile−char interactions as well.

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“…Due to the complexity of the coal structure, overlapping absorption peaks exist in its infrared spectra, and the peaks are difficult to analyze directly. Therefore, reasonable infrared structure parameters can represent the actual FTIR organic structure data [17]. In this paper, the infrared spectra of the samples were fitted by Peakfit 4.12 software, and a semiquantitative analysis was performed.…”

Section: Ftir Semiquantitative Analysismentioning

confidence: 99%

Effect of Solvent Pretreatment on the Flash Pyrolysis Performance of Yinggema Lignite

Mo,

Kan,

et al. 2023

Sustainability

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Yinggema lignite (YL) was pretreated with isometric acetone/carbon disulfide mixed solvent to obtain the residue (RYL) and, then, RYL was separated by density difference with carbon tetrachloride to obtain the light residue (LRYL). The flash pyrolysis performances of YL and LRYL were analyzed by thermogravimetry–Fourier transform infrared spectrometer–Gas chromatography/mass spectrometer (TG-FTIR-GC/MS). The results showed that solvent pretreatment could remove some small molecules in the coal and swell the used coal, leading to the increase in pyrolysis reactivity. The intensity and absorption peak area of C=O from LRYL were significantly reduced compared to YL, resulting from the high hydrogen-donating ability of acetone. The main gaseous products of both samples are H2O, CH4, CO2, and CO; the hydrocarbons detected by GC/MS in the pyrolysis products of YL and LRYL at 450 °C were mainly alkanes, alkenes, and arenes, with the higher relative contents of alkanes of 31.1% and 36.2%, followed by arenes of 27.1% and 22.6%, respectively. The oxygen-containing compounds were mainly alcohols and phenols. It is speculated that the pretreated coal could expose more oxygen-containing functional groups, facilitating their conversion to phenolic hydroxyl groups during the pyrolysis process, resulting in more phenolic compounds.

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Influence of different state alkali and alkaline earth metal on chemical structure of Zhundong coal char pyrolyzed at elevated pressures

Cited by 41 publications

References 44 publications

Mechanism of CO₂ and H₂O Action on Char in Oxy-fuel Combustion with Wet Flue Gas Recirculation

Mechanism of CO₂ and H₂O Action on Char in Oxy-fuel Combustion with Wet Flue Gas Recirculation

Changes in Biochar Functional Groups and Its Reactivity after Volatile–Char Interactions during Biomass Pyrolysis

Effect of Solvent Pretreatment on the Flash Pyrolysis Performance of Yinggema Lignite

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Influence of different state alkali and alkaline earth metal on chemical structure of Zhundong coal char pyrolyzed at elevated pressures

Cited by 41 publications

References 44 publications

Mechanism of CO2 and H2O Action on Char in Oxy-fuel Combustion with Wet Flue Gas Recirculation

Mechanism of CO2 and H2O Action on Char in Oxy-fuel Combustion with Wet Flue Gas Recirculation

Changes in Biochar Functional Groups and Its Reactivity after Volatile–Char Interactions during Biomass Pyrolysis

Effect of Solvent Pretreatment on the Flash Pyrolysis Performance of Yinggema Lignite

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Product

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Mechanism of CO₂ and H₂O Action on Char in Oxy-fuel Combustion with Wet Flue Gas Recirculation

Mechanism of CO₂ and H₂O Action on Char in Oxy-fuel Combustion with Wet Flue Gas Recirculation