Suppression of crosslinking combination of carboxyl functional groups with NaOH on combustion performance of Shengli lignite

Yan, Zhenghao; Chen, Jiaming; He, Rong; Li, Na; Zhou, Huacong; Song, Yinmin; Zhi, Keduan; Teng, Yan; Liu, Quansheng

doi:10.1016/j.fuel.2018.04.058

Cited by 19 publications

(15 citation statements)

References 42 publications

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“…This is mainly because the treatment with high-concentration alkali, on the one hand, directly removes small molecular organic matter and short-chain alkanes on the surface of coal and, on the other hand, destroys bridge bonds and hydrogen bonds, causing the consumption of active hydrogen, thereby reducing the aliphatic C–H content in coal . In addition, it can be found from Figure b that the −COOH contents of both ZB-PH10 and ZB-0.5M showed different degrees of decline owing to NaOH reacting with carboxylic acid to form sodium carboxylate . It is worth noting that the contents of both the total carbonyl compound and the highly conjugated CO in ZB-0.5M coal decreased significantly.…”

Section: Resultsmentioning

confidence: 99%

“…31 In addition, it can be found from Figure 10b that the −COOH contents of both ZB-PH10 and ZB-0.5M showed different degrees of decline owing to NaOH reacting with carboxylic acid to form sodium carboxylate. 17 It is worth noting that the contents of both the total carbonyl compound and the highly conjugated CO in ZB-0.5M coal decreased significantly. This mainly involves the aldol condensation reaction of some carbonyl-containing compounds such as ketone groups and aldehyde groups in coal in a relatively highly alkaline environment, and the carbon−oxygen double bonds are opened to form hydroxycarbonyl compounds.…”

Section: 3mentioning

confidence: 92%

“…16 At the same time, it is worth noting that alkali treatment also alters the type and amount of specific functional groups inside the lignite molecule, resulting in a significant effect on the combustion characteristics of lignite. Yan et al 17 found that the maximum combustion rate of Shengli lignite after the 0.5M NaOH pretreatment occurred at a higher temperature than that of untreated coal samples, indicating that NaOH treatment significantly decreased the combustion reactivity of Shengli lignite. Liu et al 18 researched combustion characteristics of NaOH-treated and untreated Xilihaote lignite and concluded that both the ignition and peak temperatures of the treated coal sample were higher compared to those of raw lignite.…”

Section: Introductionmentioning

confidence: 99%

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Effect of NaOH Treatment on the Low-Temperature Oxidation Behavior of Lignite

et al. 2019

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The physicochemical structure and spontaneous combustion characteristics of lignite change significantly after treatment with NaOH solution. Laboratory studies were undertaken to investigate the effect of different NaOH concentrations on the low-temperature (T < 200 °C) oxidation behavior of lignite. The experimental results showed that the low-temperature oxidation process of coal is divided into two stages by the apparent activation energy values, namely the slow oxidation stage and the rapid oxidation stage. In the first stage (T < 100 °C), the treatment with NaOH increased the coal pore volume by 8.3− 38.7% and the porosity increased by 13.9−42.1%, resulting in the oxidation intensity of coal treated with NaOH being higher than that of raw coal due to the adsorption of more oxygen. In the second stage (T > 100 °C), high-concentration NaOH treatment remarkably reduced the content of reactive functional groups including aliphatic hydrocarbons, carboxyl groups, and carbonyl groups, thereby inhibiting the oxidation reaction behavior of coal. However, the low-concentration NaOH treatment had a catalytic effect on oxidation reaction by effectively weakening the hydrogen-bonding force of coal molecules and reducing the stability of the coal structure. Meanwhile, the crossing-point temperatures of coal treated with NaHCO 3 and NaAc were 4.7 and 2.9 °C lower than those of raw coal, respectively, further indicating that the treatment with low-concentration alkali increases the spontaneous combustion propensity of coal.

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Section: Resultsmentioning

confidence: 99%

Section: 3mentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

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Effect of NaOH Treatment on the Low-Temperature Oxidation Behavior of Lignite

et al. 2019

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“… 2 , 3 However, it also has some defects, such as low calorific value, high moisture content, and high spontaneous combustion tendency. 4 The process of coal spontaneous combustion is very complex. For a long time, scholars at home and abroad have carried out a lot of research on the mechanism of coal spontaneous combustion, and the coal oxygen composite theory has been most widely recognized.…”

Section: Introductionmentioning

confidence: 99%

“…Coal is the main traditional energy source, which dominates the world’s energy consumption, especially in China . Lignite is a kind of widely used low-rank coal that has large reserves, low cost, high chemical reactivity, and low pollution. , However, it also has some defects, such as low calorific value, high moisture content, and high spontaneous combustion tendency . The process of coal spontaneous combustion is very complex.…”

Section: Introductionmentioning

confidence: 99%

Study on the Formation Mechanism of the Pyrolysis Products of Lignite at Different Temperatures Based on ReaxFF-MD

Zhu

Huo

et al. 2021

ACS Omega

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The internal part of coal that is not in contact with oxygen will undergo pyrolysis reaction due to heat conduction, and the active groups generated can reverse-aggravate the degree of coal spontaneous combustion. At present, a few studies have been conducted on the pyrolysis mechanism of coal at different temperatures by using mutually validated experimental and simulation methods, resulting in the mismatch between the microscopic mechanism and macroscopic characteristics. In this paper, DH lignite is taken as the research object, and its macromolecular model is established. The pyrolysis reaction of lignite is studied by the experimental methods of coal pyrolysis index gas collection and detection experimental and thermogravimetric analyses and the simulation method of ReaxFF-MD. The influence of temperature on lignite pyrolysis is explored by analyzing the distribution of products at different temperatures and the formation mechanism of typical products, so as revealing the microscopic mechanism of lignite pyrolysis. The results show that 110–500 K of experimental temperature corresponds to 1400–2400 K of simulation temperature. CO 2 and C 2 H 4 are the main gas products during pyrolysis simulation. Carboxyl and ester groups are the main source of CO 2 , which gradually increases with the rise of temperature. Since CO 2 can be reduced to produce CO, H 2 O, and C 2 H 2 O at high temperatures, the yield decreases when the temperature is higher than 2000 K. C 2 H 4 is derived from the decomposition of long-chain aliphatic hydrocarbons, and its yield fluctuation rises with the rise of temperature. The formation of H 2 O and H 2 mainly occurs in the secondary pyrolysis stage. When 1400 K < T < 2100 K, the primary pyrolysis is the main reaction, where the weak bridge bonds and macromolecular structure undergo cleavage to form gas products and tar free radical fragments. When T > 2100 K, the secondary pyrolysis reactions were significant. Tar free radicals and char undergo decomposition, hydrogenation, and polymerization reaction, gas products and tar free radicals increase, and the char yield decreases compared with the primary pyrolysis stage, so 2100 K is the key temperature of the pyrolysis reaction. The research is of great importance in improving the accurate control of coal spontaneous combustion.

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Production of V‐Doped P2‐type Na_0.67Mn_0.5Fe_0.43Al_0.07O₂Cathodes and Investigation of Na‐Ion Full Cells Performance

Dogan,

Altundag,

Altin

et al. 2023

Energy Tech

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The Na0.67Mn0.5−xVxFe0.43Al0.07O2 (x = 0–0.1) samples are successfully produced and their structural properties are investigated by common techniques. The highest surface area is found as 4.94 m2 g−1 for x = 0.04 V by the Brunauer–Elmet–Teller analysis. According to X‐ray photoelectron spectroscopy of x = 0.04 V‐doped sample,V4+, and V5+ ions are formed in the structure. The main phase is observed as P63/mmc symmetry with an impurity phase of V6O13 for x ≥ 0.06 . According to the CV analysis, while the redox voltage decreases for the Mn3+/Mn4+ , the intensity of the peaks of Fe2+/Fe3+ redox reaction decreases. While the best capacity value of the half cells at C/3‐rate is obtained as 171 mAh g−1 for x = 0.04, the lowest capacity fade is found for x = 0.08 . It is mentioned the V6O13 may contribute to the electrochemical process . The galvanostatic tests are investigated for the voltage windows of 3.5–1.5, 4–1.5, 4–2.5, 4–2, and 4–2.5 V and it is seen that the battery cells for 3.5–1.5 V have the best capacity fade (6%) among the others. The Na0.67Mn0.46V0.04Fe0.43Al0.07O2/ hard carbon is used for the full cells with presodiated anode and the first capacity value of the full cell is obtained as 80.2 mAh g−1 for C/2‐rate.

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Suppression of crosslinking combination of carboxyl functional groups with NaOH on combustion performance of Shengli lignite

Cited by 19 publications

References 42 publications

Effect of NaOH Treatment on the Low-Temperature Oxidation Behavior of Lignite

Effect of NaOH Treatment on the Low-Temperature Oxidation Behavior of Lignite

Study on the Formation Mechanism of the Pyrolysis Products of Lignite at Different Temperatures Based on ReaxFF-MD

Production of V‐Doped P2‐type Na_0.67Mn_0.5Fe_0.43Al_0.07O₂Cathodes and Investigation of Na‐Ion Full Cells Performance

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Suppression of crosslinking combination of carboxyl functional groups with NaOH on combustion performance of Shengli lignite

Cited by 19 publications

References 42 publications

Effect of NaOH Treatment on the Low-Temperature Oxidation Behavior of Lignite

Effect of NaOH Treatment on the Low-Temperature Oxidation Behavior of Lignite

Study on the Formation Mechanism of the Pyrolysis Products of Lignite at Different Temperatures Based on ReaxFF-MD

Production of V‐Doped P2‐type Na0.67Mn0.5Fe0.43Al0.07O2Cathodes and Investigation of Na‐Ion Full Cells Performance

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Product

Resources

About

Production of V‐Doped P2‐type Na_0.67Mn_0.5Fe_0.43Al_0.07O₂Cathodes and Investigation of Na‐Ion Full Cells Performance