ACS Omega
·
2024
·
IF 3.7
Hong Zhang,Zongquan Zhao,Zihan Wang,Shibin Nie,Chao Han
Inhibitory foam technology plays an important role in inhibiting coal spontaneous combustion. To enhance the stability and inhibitory performance of inhibitory foam for coal spontaneous combustion, a novel physicochemical composite inhibitor was developed in this work. CaCl2 was chosen as an inorganic salt physical inhibitor to compound with the chemical inhibitor melatonin (MLT) due to its corresponding good foam stability. When the mass ratio of CaCl2 to MLT was 4:1, the lowest CO release concentration of 7337.06 ppm at 200 °C was observed in the composite inhibitor-treated coal. Furthermore, the addition of 20 wt % of the composite inhibitor resulted in a foam half-life of 3067 min, which was 5.89 times longer than that of the water-based foam. In comparison with the water-based foam, the inhibitory foam based on 20 wt % CaCl2–MLT composite inhibitor exhibited more excellent foam stability, wetting ability, and inhibition performance. The release of CO at 200 °C was 7854.6 ppm, showing a reduction of 63.2% compared to the raw coal. Moreover, the composite inhibitory foam could significantly delay the onset of the characteristic temperature and reduce the weight change during the decomposition stage by 12.8%.
研究领域:
矿业工程
·
消防工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Omega
·
2022
·
IF 4.132
Fei Gao,Zhe Jia,Ya-fei Shan,Yifei Teng,Ying-di Li,Xin-ge Pu
The low-temperature oxidation spontaneous combustion of coal was caused by the active groups in its structure. The oxidation mechanism of carbon and oxygen functional groups in coal had been extensively studied, but there were few reports on the study of sulfur functional groups initiating the coal spontaneous combustion. To investigate the influence of organic sulfur functional groups on the spontaneous combustion of high-sulfur coal and explore its transformation characteristics, the low-temperature oxidation experimental system was used to study the spontaneous combustion tendency of coal with similar metamorphic degrees and different organic sulfur contents. The variations of element forms and organic sulfur functional groups were analyzed by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy during low-temperature oxidation of coal and model compounds. The results showed that the forms of organic sulfur in coal mainly included mercaptans, thioethers, thiophenes, sulfones (sulfoxides), and sulfates, and the low-temperature oxidation of coal was not only related to the content of organic sulfur but also related to its type. The coal samples, which possess a low content of total sulfur and a small proportion of active organic sulfur groups such as mercaptans and thioethers, had a lower concentration of indicator gas and a smaller tendency to coal spontaneous combustion. After low-temperature oxidation, the content of mercaptan, thioether, thiophene, methyl(methylene), and pyridine in coal decreased, and the content of oxygen-containing groups such as sulfone (sulfoxide), sulfate, carboxyl, and nitrogen oxide increased. The elements of S, C, and N all changed to a high-valent state. In the oxidation reaction of model compounds, mercaptans were more reactive than thiophenes in the low-temperature region, and the oxidation of thiophene could direct form sulfone (sulfoxide), while the oxidation of mercaptan formed disulfide first. It is speculated that low-valence sulfur migrated to a high-valent state by providing sulfhydryl radicals (•SH) and sulfur radicals (C–S•) combined with active oxygen atoms. After the low-temperature oxidation reaction of model compounds, some organic sulfur existed in the form of aromatic sulfur or sulfur oxides and a small part of sulfur escaped as SO2 and H2S gases in the solid oxidation product.
研究领域:
矿业工程
·
化学工程
✓ 已验证
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Lei Shi,Ping Xu,Rui Wang,Weixin Tang,Tao Ding,Rongpei Jiang,Changhua Zhang
Ignition delay times of JP-10 in air and the vitiation effect of NO 2 on JP-10 autoignition at high temperatures were investigated behind reflected shock waves. The experiments were carried out at pressures of 2 and 10 atm, temperatures between 900 and 1460 K, fuel lean and stoichiometric conditions with and without 1.0 % NO 2 . The experimental results show that the ignition delay times of JP-10/air decrease with the increase of pressure or the decrease of equivalence ratio. The effect of adding 1.0 % NO 2 is pressure dependence. At 10 atm, the addition of NO 2 promotes the ignition of fuel, which shortens the ignition delay time. At 2 atm, the addition of 1.0 % NO 2 inhibits the ignition of JP-10, which prolongs the ignition delay time. A chemical kinetic mechanism of JP-10/NO 2 consisting of 290 species and 1768 reactions was developed by extending from a C0-C5 alkane and a cyclopentene sub-mechanism. The proposed mechanism has been well validated by ignition delay times, laminar flame speeds and species concentration profiles from literature. To further investigate the autoignition of JP-10 and the vitiation effect of NO 2 , kinetics analyses including reaction pathways and sensitivity coefficients were performed by the developed mechanism. The main consumption pathways of JP-10 in air are H-abstraction reactions from JP-10 by HO 2 radicals. With 1.0 % NO 2 vitiation, the addition of NO 2 has a strong effect on JP-10 consumption via the H-abstraction pathway JP-10 + NO 2 = C 10 H 15 + HONO, which further affects the autoignition of JP-10.
研究领域:
燃烧学
·
化学动力学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2025
·
IF 9.5
Qing Cheng,Yuqi Zhang,Yingying Cao,Peihao Dou,Long Liu,Yanqiang Zhang
Ionic liquid-H2O2 is a green hypergolic propellant system, and the poor self-ignition hinders its application. Herein, the stable zero-valent catalyst Cu nano-particle with twin boundaries (T-Cu) was synthesized. As the twin boundary regulates the electron micro-environment of the T-Cu surface, the electron transfer from the d electrons of Cu atom to the σ* anti-bonding orbital of H2O2 is intensified to create ·OH and ·OOH. The resulted free radicals possess strong oxidizing ability, and react violently with [BMIM]N(CN)2 to achieve a rapid ignition with the delay time as low as 25 ms. This work provides an effective way to get excellent ignition performance, and promotes the application of Ionic liquid-H2O2 green hypergolic propellants.
研究领域:
材料科学
·
推进剂工程
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2023
·
IF 6.1
Hongwei Ren,Hongyu Dong,Tengda Zhao,Zhongqing Yan,Benzhen Jia,Liang Han,Jinfeng Zhang
Activated carbon (AC) is one of the typical adsorbents for industrial treatment of VOCs, but AC itself has a high calorific value. When the heat generated by low-temperature oxidation cannot be released, it is easy to store heat and oxidize spontaneously, resulting in immeasurable harm. Therefore, it is important to study and improve the thermal stability of AC. In this study, Mo-doped carbon quantum dots (CQDs) was synthesized to enhance the safety of AC usage. The structure of AC before and after modification was characterized by transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffractometer (XRD). On the modified Mo-doped CQDs/AC, there are more crystalline structures formed by Mo oxides on the surface, which makes the intermolecular force on the surface of AC increase. At the same time, Mo oxide has strong oxidation resistance, which can inhibit the thermal decomposition process of AC, and has stronger stability. The spontaneous combustion tendency and thermal hazard of AC before and after modification were greatly improved. The heat released in the toluene adsorption by the modified AC at different temperatures was significantly lower than the heat released by the unmodified AC. According to the Langmuir adsorption isotherm, the adsorption performance of Mo-doped CQDs (2.5 wt%) was 1.6 times higher than that of AC when the system was 25 °C. The results showed that Na 2 MoO 4 CQDs modified AC could effectively improve the thermal stability and greatly reduce the spontaneous combustion tendency. A relative fire safety performance evaluation model was also established to comprehensively evaluate the fire risk of VOCs treatment by AC.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Coal Preparation and Utilization
·
2024
·
IF 2
Yanrui Guo,Xiaogang Mu,Cunbao Deng,Hongfei Duan,Ling Qiao,Qianru Du,Peng Jing
Spontaneous combustion of coal is one of the main natural disasters in the process of coal mining, and spontaneous combustion of sulfur-containing coal is an urgent problem to be solved. In order to understand the influence of different sulfur structures and sulfur content on spontaneous combustion tendency of coal, the self-developed synchronous temperature compensation adiabatic oxidation experiment system was used to study the oxidation self-heating performance of a series of sulfur-containing “coal-like materials.” Through the analysis of the heating rate of coal containing specific sulfur structure, it is considered that the time of adiabatic oxidation temperature of different organic sulfur “coal” to rise to 70°C is dimethyl sulfoxide > phenylene sulfide > dibenzothiophene. By analyzing the oxidation temperature rise characteristics of organic sulfur models with different sulfur contents, it is believed that the higher sulfur content, the faster the low temperature oxidation reaction of “coal-like substance,” the faster the temperature rise rate, and the shorter the time to reach the uncontrollable self-heating temperature, so the shorter the spontaneous combustion period. In general, in the stage of low temperature oxidation, active sulfur containing small molecules (dimethyl sulfoxide) promote the oxidation temperature rise, stable structure, larger molecular weight of dibenzothiophene slow down the “coal-like” oxidation temperature rise.
研究领域:
矿业工程
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2020
·
IF 3.99
Lei Wu,Guansheng Qi,Wei Lu,Zhenglong He,Jialiang Li,Jinliang Li,Min He
In the process of coal mining, coal spontaneous combustion in the gob area poses serious threats to the safety of mine production. Besides, coal combustion also produces a large amount of greenhouse gas CO 2 , which triggers a series of ecological environment problems. In order to solve these two problems, the idea of mineralizing CO 2 with the alkaline industrial waste calcium carbide slag and then sending the foams to the gob area for coal spontaneous combustion prevention was proposed in this study. First, the effects of calcium carbide slag foaming under the action of different types of foaming agents, including sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS), polyoxyethylene fatty alcohol sodium sulfate (AES), and octyl decyl glucoside (APG0810), were tested and analyzed. Furthermore, the effects of water glass (WG), sodium alginate (SA), polyvinyl alcohol 1799 (PVA), cement, and silica micro-powder on the foam stability were analyzed by investigating the stability coefficient and drainage volume of calcium carbide slag foam. On this basis, the configuration scheme of calcium carbide slag foam with high efficiency and good stability was determined. The experimental results on CO 2 mineralization and coal spontaneous combustion inhibition reveal that the prepared calcium carbide slag foam can rapidly absorb CO 2 . Moreover, after calcium carbide slag foam treatment, the spontaneous combustion tendency of the coal sample is significantly reduced.
研究领域:
矿业工程
·
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2021
·
IF 19.503
Qi Li,Yi-lei Li,Bo Li,Ying-juan Hao,Xiao-jing Wang,Rui-hong Liu,Yuan Ling,Xinying Liu,Fa-tang Li
In layered Bi-O-X materials, {001} and {110} facets are regarded to be highly active. However, dominant facets in bismuth-rich materials are rarely studied so far. In this paper, the role of main {314} facet of Bi 5 O 7 I is investigated for the first time. Bi 5 O 7 I samples with adjustable {314} and {008} facet ratios are synthesized using ionic liquid self-combustion method. The inducing growth role of tetramethylammonium iodide for {314} main facet is revealed. Photocatalytic experiments indicate that the activity of Bi 5 O 7 I material with {314}/{008} facet ratio of 4.32 are lower than those of Bi 5 O 7 I with facet ratio of 5.23 and 4.56, implying the increase of {008} facet proportion could not effectively improve the redox performance. Meanwhile, the controllable oxygen vacancy concentration can be realized by constructing reduction atmosphere. Photoelectrochemical test results show that the synergistic effect of facet ratio and the oxygen vacancies lead to the improvement of charge carriers.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2021
·
IF 6.609
Chunhua Zhang,Jiahui Shen,Ji Li,Mei Wan
To study the inhibition characteristics of different chloride salts on the spontaneous combustion of coal and to further reveal why magnesium chloride shows a different inhibitory effect, coal samples from FuSheng Coal Mine No. 15 in Shanxi Province were selected. Based on the characteristics of functional group absorption peak at different temperature, the composition changes and reactivity ranking of the functional groups in oxidized coal samples were tested by thermal oxidation experiments and infrared spectroscopy and analyzed to obtain the chain thermal reactions of different active groups. The weight-loss process and heat release characteristics of raw coal and three chloride salt-containing coal samples (sodium chloride, potassium chloride, and magnesium chloride) were compared and analyzed by synchronous thermal analysis experiments, and their inhibition reaction mechanism were studied. The results showed that different functional groups reacted at different low-temperature stages, and the active groups containing C–H, O–H, C-O, and C = O bonds were important during the spontaneous combustion of coal. In the chain thermal reactions with different active groups, heat and oxidative cleavage of the C-O and O–H bonds determined the chain development of different functional groups, and the R·, RO·, H·, and ·OH, chain thermal reaction products again acted as reactants that promoted further development of the reaction. Sodium chloride and potassium chloride played inhibitory roles in the dehydration-desorption stage and dynamic equilibrium stage through water evaporation and heat absorption, while magnesium chloride participated in the whole coal-oxygen reaction process. The inhibitory mechanism included dehydration and heat absorption by MgCl 2 ·6H 2 O, the complex dehydration of active groups containing O–H, the precipitation and oxygen insulation of [(SH·) n ]Mg and Mg(OH) 2 , the nucleophilic substitution of α-H for RCH 3 and RCH 2 OH groups, and the formation of H…Cl…H bonds.
研究领域:
化学工程
·
能源科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Fei Gao,Zhe Jia,Qihui Bai,Jianjun Dong
Inhibitors play an important role in preventing and controlling coal spontaneous combustion (CSC). In this study, the inhibitory effects of antioxidant-reduced glutathione (G-SH) on CSC were examined. Thermogravimetric-differential scanning calorimetry (TG-DSC), cross-point temperature (CPT), and oxidation product tests were used to examine the effect of G-SH on the tendency of CSC and compare the discrepancy in the inhibition effect of G-SH and the halogen inhibitor. The changes in the free radical type, concentration, and surface functional groups in coal before and after the addition of G-SH were analyzed using electron spin resonance spectroscopy (ESR) and Fourier transform infrared spectroscopy (FT-IR). Six common active radical models were constructed, and the thermodynamic parameters of the reaction were calculated using density functional theory (DFT). The results revealed that G-SH inhibits the spontaneous combustion of coal. The inhibitory effect of G-SH was significantly stronger than that of the halogen salt inhibitors CaCl 2 and MgCl 2 , and the higher the concentration of G-SH, the stronger is the inhibitory effect. The characteristic temperature points in the thermogravimetric experiment of coal samples with G-SH shifted to a higher temperature zone, and the CO concentration and oxygen consumption were lower than those of raw coal. After G-SH treatment, the type and relative concentration of free radicals in coal were lower than those in raw coal, the content of aliphatic hydrocarbon functional groups and oxygen-containing functional groups decreased, and the content of sulfur-containing functional groups increased. According to the calculation of Gibbs free energy and reaction enthalpy, G-SH can effectively neutralize the active free radicals in the process of coal oxidation, and the reaction activity with the free radicals in the process of coal oxidation is ·OOH > ·OH > ·CH 3 > RO· > R· > ROO·. According to the experimental results, it is inferred that G-SH continuously supplies a large number of hydrogen donors (·H) for the reaction during the oxidation process and simultaneously neutralizes carbon free radicals and carbon oxygen free radicals, thereby reducing the concentration and reactivity of free radicals in the whole chain reaction process and blocking the occurrence of coal-oxygen composite reaction.
研究领域:
能源科学
·
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Energies
·
2023
·Vol. 16
·期 8
·3333
·
IF 3.2
Derui Jin,Ji Mi,Yongsheng Guo,Yitong Dai,Wenjun Fang
It was found in our previous work that hyperbranched polyester (HPE) can generate radicals and accelerate the chemical reactions of hydrocarbon fuels used as initiators. In this work, the evaporation and autoignition characteristics of JP-10 droplets with or without HPE were investigated using the high-speed backlight imaging technique in detail. The results indicate that the puffing and micro-explosion phenomena of HPE-blended JP-10 droplets can accelerate fuel evaporation and autoignition. When a 0.1% mass concentration of HPE was used, the droplet lifetime was reduced by 16.5% in evaporation at 850 K and 18.0% in autoignition at 900 K. A mechanism of HPE that promotes puffing and micro-explosions was proposed by analyzing droplet images of combustion and SEM images of combustion residues. Overall, this study provides a method for improving the evaporation and autoignition performance of JP-10.
研究领域:
燃烧学
·
化学工程
·
航空动力学
✓ 已验证
产品关联
DOI
高影响因子
E-POLYMERS
·
2015
·Vol. 15
·期 5
·361-368
·
IF 0.569
Xiangming Hu,Weimin Cheng,Zhenlu Shao
Authigenic gas foaming hydrogels were synthesized using chitosan (CS), acrylic acid, and attapulgite (APT) as hydrophilic monomers; potassium persulfate as initiator; N,N′-methylenebisacrylamide as cross-linker; and sodium carbonate (Na 2 CO 3 )/acetic acid as foaming agent. Effects of different monomers, amount of foaming agent, and temperature on swelling ratio (SR) of the hydrogels were examined. Morphology, structure, and thermal stability of authigenic gas foaming hydrogels were studied using field emission scanning electron microscope, Fourier-transform infrared spectroscopy, and synchronous thermal analysis. Scanning electron microscope images reveal apparent pores on hydrogels, produced by foaming agent Na 2 CO 3 /acetic acid. Therefore, more foaming agent would bring more pores on hydrogels. Synchronous thermal analysis results suggest that higher amount of CS would result in higher thermostability of hydrogels. However, APT has no substantial effect on thermal stability. SR decreases with increasing amount of CS. Hydrogels prepared at 70°C reaction temperature exhibit maximum swelling. Furthermore, SR decreases with higher covalence of saltion.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）