Greenhouse Gases-Science and Technology
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2021
·Vol. 11
·期 5
·974-987
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IF 2.013
Shunji Kang,Zhi Shen,Xizhou Shen,Liuya Fang,Li Xiang,Wenze Yang
The carbon dioxide discharged from fossil fuels combustion products is considered as a major contributor to global warming. The current investigation aimed at CO 2 desorption kinetics in 3.25 mol L –1 methyldiethanolamine (MDEA)–0.1 mol L –1 piperazine (PZ) rich amine aqueous solution with thermo-gravimetric analysis (TGA) method under different heating rates of 2.5, 5, 10, and 20 °C min –1 . The kinetics parameters were determined by comparison of 40 mechanism functions with thermal analysis kinetic method. The average activation energy E was 59.16 kJ mol –1 , preexponential factor A was 5.54 × 10 8 , and the most probable mechanism function was G( α ) = [–ln(1 – α )] 3/2 . In addition, the kinetic parameters of CO 2 desorption process from three rich amine aqueous solutions (MDEA, MDEA + diethanolamine(DEA), MDEA + PZ) were compared and the influence of kinetic parameters was further discussed. The desorption rate models of three rich amine aqueous solutions were established and desorption rates were well predicted. The order of desorption rate inferred from desorption rate model was MDEA > MDEA + DEA > MDEA + PZ. The results indicated that TGA combined with thermal analysis kinetics was an effective and quick method with high accuracy, easy operation, and good repeatability for screening absorbents preliminarily in laboratory. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd.
研究领域:
化学工程
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环境科学
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热分析
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DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2024
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IF 5.8
Junsong Zhang,Yiqun Wang,Yuanyang Zhu,Man Su,Yifei Xie,Yongjie Zheng,Haibo Zhu,Miao Liang,Ruili Li,Xiaoyun Zheng
An in-depth insight into the pyrolysis characteristics of tobacco is of great significance for the utilization of tobacco wastes. The effects of glycerol addition on the pyrolysis characteristics and distribution of aroma components of four types of tobacco was investigated in this study by using thermogravimetry and self-built rapid heating furnace capture and GC-MS analysis. Further, correlation network analysis was used to study the correlation between pyrolysis characteristics and released aroma components. It was found that the thermal weight loss behavior of different samples exhibited both commonalities and differences, the thermal weight loss process could be divided into four stages. After the application of glycerol, the overall performance of all types of tobacco leaves at stage II showed that DTG max2 and WL 2 increased, and glycerol had a relatively obvious effect on the pyrolysis characteristic parameters of flue-cured tobacco. Pyrolysis kinetic analysis based on Coats-Redfern method showed that the activation energy and pre-exponential factor of tobacco samples were decreased after the addition of glycerol. Under the heating condition, the total amount of released aroma components from each type of tobacco followed the order of burley tobacco > flue-cured tobacco >oriental tobacco > yellow sun-cured tobacco. The release amount of heterocyclic and olefins compounds from burley tobacco were higher, while flue-cured tobacco released higher contents of esters, ketones and furans compounds. The addition of glycerol promoted the release of aroma components. In terms of correlation, T max2 was negatively correlated with esters, aldehydes, and furans compounds, and positively correlated with DTG max3 . T max3 was significantly correlated with a lot of indicators, positively with acids, aldehydes, and furans compounds, but negatively with olefins and heterocyclic compounds.
研究领域:
化学工程
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分析化学
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农业科学
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食品科学
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环境科学
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高影响因子
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2019
·Vol. 35
·期 4
·674-679
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IF 1.071
Shen Xizhou,Song Hao,Fang Liuya,Deng Hang,Gan Feng,Shen Zhi
Since the content of thiophene in coking crude benzene is high, it is necessary to remove it from coking crude benzene for efficient utilization. In this study, an important intermediate, N, N -dimethyl-2-thiophenecar-boxamide, was synthesized from thiophene and dimethylcarbamyl chloride. The influences of the dosages of dimethylcarbamyl chloride and ZnCl 2 catalyst, reaction temperature and time on the removal rate were further explored based on the reaction kinetics. The structure of the target product was characterized by means of MS, 1 H NMR and 13 C NMR. The removal rate of thiophene was 98.14% after the reaction for 2 h and thiophene was almost removed after the reaction for 3 h under the optimal reaction conditions[a molar ratio of n (thiophene): n (dimethylcarbamyl chloride): n (ZnCl 2 )=1:12:10, 300 r/min, 318 K and 101.325 kPa]. The acylation of thiophene with dimethylcarbamyl chloride was approximately in accord with the first order kinetic equation at 303–323 K. The activation energy was 53.9850 kJ/mol and the pre-exponential factor was 1.4521×10 9 h −1 .
研究领域:
化学工程
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有机化学
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催化
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石油炼制
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DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
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2024
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IF 4.1
Yanan Li,Yuqi Wang,Jinlei Wu,Shuqin Gao,Binjing Zhu,Junqian Wang,Jing Zhao,Le Wu,Lan Zheng,Xiaoli Zhang
Dry reforming of methane (DRM) is considered one of the most efficient methods for carbon utilization, as it can transform greenhouse gases (CH 4 and CO 2 ) into syngas (CO and H 2 ) which could be widely used in the production of high-value hydrocarbons. The synergistic effect between Ni and Co is leveraged to enhance the coke resistance and stability of Ni-based catalyst during the DRM process, building upon the surface spatial confinement provided by honeycomb-lantern-like CeO 2 support. The enhanced catalytic performance of Ni 0.9 Co 0.1 catalyst can be attributed primarily to the addition of cobalt, which facilitates CO 2 adsorption and activation, further promotes the Boudouard reaction and aids in the elimination of coke. This phenomenon is supported by evidence from CO 2 -TPD, XPS, SEM, TGA, XRD, and CO 2 -TPO analyses. Furthermore, the kinetics of Ni 0.9 Co 0.1 are examined using Power-Law (PL) and Langmuir-Hinshelwood (LH) mechanisms, obtaining the explicit equations for the rate constants ( k and k r ), reaction orders of the reactants (α and β), and adsorption equilibrium constants ( K CH 4 and K CO 2 ). The comparison of the predicted CH 4 consumption rates with the experimental rates suggests that the LH mechanism is notably more precise than PL mechanism for Ni 0.9 Co 0.1 catalyst. Moreover, the relevant kinetic parameters (the activation energy and pre-exponential factor), pertinent to coke gasification process for the spent Ni 0.9 Co 0.1 and Ni 1.0 , are determined and calculated through CO 2 -TPO characterization and the modified Wigner-Polanyi equation.
研究领域:
催化
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化学工程
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材料科学
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环境科学
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DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2015
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IF 3.564
Xue-Jie Wang,Jin-zong You,Feng Yu
The thermal decomposition of emtricitabine (FTC) was measured with thermogravimetry (TG), differential scanning calorimetry (DSC), and thermogravimetric analysis coupled with Fourier transform infrared spectroscopy (TG-FTIR). The infrared (IR) spectra, high performance liquid chromatography (HPLC), and liquid chromatography mass spectrometry (LC–MS) of FTC and the residues of its thermal decomposition at various temperatures were determined. The molecular bond orders were calculated with an ab initio method from the GAMESS program. The mechanism of thermal decomposition of FTC was discussed. The kinetic parameters of thermal decomposition such as activation energy E a and the pre-exponential factor A were obtained with the Ozawa method. The prospective lifetime of FTC was estimated with the Dakin equation. The results indicated that the thermal decomposition of FTC is a two-step process. In the thermal decomposition process, most of FTC decomposes directly to small molecules and insoluble substance due to the fracture of the N C bond of amide in the 5-fluorocytosine ring, a small amount of FTC decomposes to 5-fluorocytosine due to the fracture of the N -glycosidic bond, and a small amount of 5-fluorouracil and 2′,3′-dideoxy-5-fluoro-3′-thiauridine are generated due to the oxidation reaction. The initial decomposition temperature either nitrogen or air is 200 °C. For decomposition in nitrogen, the E a and A for the initial thermal decomposition are 142.4 kJ mol −1 and 2.09 × 10 13 min −1 , respectively. For decomposition in air, the corresponding E a and A are 140.7 kJ mol −1 and 1.62 × 10 13 min −1 , respectively. The thermal stability of FTC is very good under routine temperatures.
研究领域:
药物化学
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物理化学
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分析化学
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高影响因子
危险品化学品经营许可证（带存储）