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A Model-based Phenomenological Investigation of Char Combustion Kinetics through thermogravimetry

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Chinese Chemical Letters 2005年第3期16卷 393-396页

作者： QunCHEN RongHE ZhanGangLIANG XuChangXU ChangHeCHEN DepartmentofThermalEngineering TsinghuaUniversityBeijing10084

Five coal char samples were burnt in thermobalance with ramp heating rate of 30 K/min. The pore structure of these char samples was studied through mercury intrusion method. Combined with the kinetic theory of gases, the data of surface area was used in fitting the results. As a result, the kinetic triplet was given. The analysis showed that five char samples share almost the same intrinsic activation energy of the overall reaction. The phenomenological implication of the derived combustion rate equation was given.

关键词： thermogravimetry activation energy pre-exponential factor kinetic model function char combustion.

A combined kinetic study on the pyrolysis of chrome shavings by thermogravimetry

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Carbon Resources Conversion 2020年第1期3卷 156-163页

作者： Jie Liu Lan Luo Zonghui Zhang Yadi Hu Fang Wang Xiumin Li Keyong Tang School of Materials Science and Engineering Zhengzhou UniversityZhengzhouHenan 450001China

Chrome shavings(CS),a kind of solid wastes discharged from tanneries,always pose serious environmental problems due to the presence of *** this work,kinetic study of the pyrolysis of CS was investigated using a thermogravimetric analyzer in nitrogen *** results obtained from the thermogravimetric analysis indicated that there are three stages in the temperature range 25 to 600℃.The second stage is the main weight loss stage and it could be mainly attributed to the pyrolysis of collagenous ***-conversional and generalized master-plots method were first employed to estimate the activation energy value and possible reaction mechanism of CS *** results showed that the pyrolysis process could not be described accurately by single-step reaction due to the heterogeneous nature of ***,the thermogravimetric kinetic of CS pyrolysis was studied using combined kinetic *** was found that three-parallel-reaction model allowed better fitting relevance for CS *** information was important for simulating and predicting the pyrolysis behaviors of CS.

关键词： Chrome shavings Combined kinetics Pyrolysis thermogravimetry

Thermal Decomposition of Olive-Solid Waste by TGA: Characterization and Devolatilization Kinetics under Nitrogen and Oxygen Atmospheres

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Journal of Power and Energy Engineering 2024年第3期12卷 31-47页

作者： Yahya H. Khraisha Chemical Engineering Department University of Jordan Amman Jordan

Despite the fact that a few countries in the Mediterranean and the Middle East have limited crude oil reserves, they have abundant biomass feedstocks. For instance, Jordan relies heavily on the importation of natural gas and crude oil for its energy needs;but, by applying thermochemical conversion techniques, leftover olive oil can be used to replace these energy sources. Understanding the chemical, physical, and thermal characteristics of raw materials is essential to obtaining the most out of these conversion processes. Thermogravimetric analysis was used in this study to examine the thermal behavior of olive-solid residue (kernel) at three different heating rates (5, 20 and 40 C/min) in nitrogen and oxygen atmospheres. The initial degradation temperature, the residual weight at 500 and 700˚C and the thermal degradation rate during the devolatilization stage (below 400˚C) were all determined. It was found that in N2 and O2 atmospheres, both the initial degradation temperature and the degradation rate increase with increasing heating rates. As heating rates increase in the N2 atmosphere, the residual weight at 500 or 700˚C decreases slightly, but at low heating rates compared to high heating rates in the O2 atmosphere, it decreases significantly. This suggests that a longer lignin oxidation process is better than a shorter one. Coats and Redfern approach was used to identify the mechanism and activation energy for the devolatilization stage of pyrolysis and oxidation reactions. The process mechanism analysis revealed that the model of first-order and second-order reactions may adequately describe the mechanism of heat degradation of the devolatilization step of olive-solid waste for pyrolysis and oxidation processes, respectively.

关键词： Biomass Olive-Solid Waste thermogravimetry Pyrolysis Oxidation Heating Rates Kinetics

Phosphorus reduction behavior of high-phosphate iron ore during hydrogen-rich sintering

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International Journal of Minerals,Metallurgy and Materials 2022年第10期29卷 1862-1872页

作者： Yanbiao Chen Wenguo Liu Haibin Zuo State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China

High-phosphorus iron ore resource is considered a refractory iron ore because of its high-phosphorus content and complex ore phase structure. Therefore, the development of innovative technology to realize the efficient utilization of high-phosphorus iron ore resources is of theoretical and practical significance. Thus, a method for phosphorus removal by gasification in the hydrogen-rich sintering process was proposed. In this study, the reduction mechanism of phosphorus in hydrogen-rich sintering, as well as the reduction kinetics of apatite based on the non-isothermal kinetic method, was investigated. Results showed that, by increasing the reduction time from 20 to 60 min, the dephosphorization rate increased from 10.93%to 29.51%. With apatite reduction, the metal iron accumulates, and part of the reduced phosphorus gas is absorbed by the metal iron to form stable iron-phosphorus compounds, resulting in a significant reduction of the dephosphorization rate. Apatite reduction is mainly concentrated in the sintering and burning zones, and the reduced phosphorus gas moves downward along with flue gas under suction pressure and is condensed and adsorbed partly by the sintering bed when passing through the drying zone and over the wet zone. As a result, the dephosphorization rate is considerably reduced. Based on the Ozawa formula of the iso-conversion rate, the activation energy of apatite reduction is 80.42 kJ/mol. The mechanism function of apatite reduction is determined by a differential method (i.e., the Freeman-Carroll method) and an integral method (i.e., the Coats-Redfern method). The differential form of the equation is f(α)=2(1-α)^(1/2), and the integral form of the equation is G(α)=1-(1-α)^(1/2).

关键词： hydrogen-rich sintering dephosphorization reduction mechanism kinetics thermogravimetry

A Double Crown Hexakis[(Di-µ-benzylthio)Nickel]Cluster:Synthesis,Structure and Properties

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Chinese Journal of Structural Chemistry 2022年第3期41卷 40-46,I0008页

作者： LIU E JIA Ai-Quan ZHANG Qian-Feng JIAN Fang-Fang Institute of Molecular Engineering and Applied Chemistry Anhui University of TechnologyMa’anshanAnhui 243002China School of Chemical Engineering and Pharmaceutics Henan University of Science and TechnologyLuoyang 471000China

The double crown hexakis[(di-μ-benzylthio)nickel]cluster,[Ni_(6)(SCH_(2)C_(6)H_(5))_(12)]·C_(2)H_(5)OH,was obtained by reacting C_(6)H_(5)CH_(2)SNa with[(CH_(3))_(2)CHOCS_(2)]_(2)Ni in *** results of electrochemical studies show that[Ni_(6)(SCH_(2)C_(6)H_(5))_(12)]is a quasi-reversible *** crystal structure of[Ni_(6)(SCH_(2)C_(6)H_(5))_(12)]·C_(2)H_(5)OH is composed of discrete[Ni_(6)(SCH_(2)C_(6)H_(5))_(12)]and C_(2)H_(5)OH solvent *** Ni atom is surrounded by four S atoms of theµ2-SCH_(2)C_(6)H_(5)ligands in a distorted square-planar *** C_(6)H_(5)CH_(2)S-side chains are arranged in the axial and equatorial positions,alternately,concerning the pseudo-hexagonal axis of the ***π-πand C-H···πeffects form the supramolecular nano-channel along the a-axis in the crystal,which wraps the solvent ethanol molecules in *** addition,a wall is formed along the b-and c-axes,so that the ethanol molecules can freely enter and leave along the *** effects result in the ability of the title compound to adsorb and desorb ethanol *** analysis and powder X-ray diffraction at different temperature are provided to demonstrate this point.

关键词： benzylthiol nickel cluster porous materials cyclic voltammetry thermogravimetry

Insight into the key kinetic steps in the pyrolysis of coking and non-coking coals,characterization of the pyrolysis products

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International Journal of Coal Science & Technology 2023年第2期10卷 169-180页

作者： P.N.Kuznetsov O.Yu.Fetisova L.I.Kuznetsova B.Avid B.Purevsuren Institute of Petroleum and Gas Siberian Federal UniversityKrasnoyarskRussia Institute of Chemistry and Chemical Technology SB RAS Federal Research Center"Krasnoyarsk Science Center SB RAS"KrasnoyarskRussia Institute of Chemistry and Chemical Technology Mongolian Academy of SciencesUlaanbaatarMongolia

The chemical composition,structural and plastometric properties of different-ranked coals from Mongolia deposits were *** non-isothermal iso-conversion Ozawa-Flynn-Wall and Friedman model-free methods were used to assess kinetic parameters and to differentiate decomposition *** peculiarities of the pyrolysis kinetics of brown and bituminous coals were revealed and discussed in terms of the composition and plastometric *** coal was shown to undergo three decomposition steps with ever increasing activation energy as temperature increased because of the decomposition of thermally more and more stable molecular *** pyrolysis of bituminous coals occurred in four steps,the activation energy having extreme mode of temperature *** important new finding was that the temperature range of the second,major pyrolysis step well corresponded to that between the softening and re-solidification temperatures according to Gieseler *** yield and composition of the pyrolysis products obtained under isothermal conditions were also characterized depending on coal rank and temperature,and the ways for qualified utilizations were offered.

关键词： Coal Pyrolysis thermogravimetry Plastometry Activation energy

Thermal stability of soil organic carbon subjected to water erosion as a function of edaphic factors

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International Journal of Sediment Research 2022年第1期37卷 26-36页

作者： Zhongwu Li Linhui Xiao Chuxiong Deng Zaijian Yuan Chen Liang Qian Xiong Zeting Li Xiaodong Nie College of Resources and Environmental Science Hunan Normal University Guangdong Engineering Center of Non-point Source Pollution Control Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management Guangdong Institute of Eco-environmental Science & Technology Guangdong Academy of Sciences National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China

The stability of soil organic carbon (SOC),as it relates to resistance to decomposition,is important for greenhouse gas emission and climate ***,the SOC stabilization and its related influencing factors subjected to water erosion remain *** objective of the current study was to determine the SOC stability under long-term water erosion and to investigate the link between SOC stability and edaphic *** samples from eroded,depositional,and control sites in a closed watershed in subtropical China were *** SOC concentration,carbon functional groups,soil physicochemical properties,and thermal stability of SOC were *** study results showed that the primary component of the SOC functional groups was O-alkyl carbon (reached 40%),and its proportion has no significant difference among different *** TG-T50(the temperature at which 50%of the soil organic matter is lost) values indicated that the SOC thermal stability in the eroded topsoil was higher than that of the deposited *** carbon functional groups were lack of relation with SOC thermal stability(p>0.05).However,the TG-T50was significantly positively correlated with the cation exchange capacity and silt,but remarkably negatively correlated with SOC,dissolved organic carbon,total nitrogen,sand,clay,p H,aluminum,specific surface area,and iron *** results indicated that the edaphic factors,which were strongly affected by micro-environment,are the main factors affecting thermal stability of organic *** SOC stabilization under the effects of long-term water erosion should be addressed from the perspective of the ecosystem.

关键词： Soil erosion Soil organic matter thermogravimetry Preservation Stability

Synthesis, Spectroscopic Characterization and Thermogravimetric Analysis of Cr(Ⅱ), Cu(Ⅱ), Zn(Ⅱ) and Mg(Ⅱ),Captopril Coordination Compounds

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光谱学与光谱分析 2020年第2期40卷 661-664页

作者： Asma SAl-Wasidi Nawal MAl-Jafshar Amal MAl-Anazi Ahmed M.Naglah Robson Fde Farias Claudio Airoldi Moamen SRefat Department of Chemistry College of SciencePrincess Nourah Bint Abdulrahman UniversityRiyadh 11671Saudi Arabia Department of Pharmaceutical Chemistry Drug Exploration and Development Chair(DEDC)College of PharmacyKing Saud UniversityRiyadh 11451Saudi Arabia Peptide Chemistry Department Chemical Industries Research DivisionNational Research CentreCairo 12622-DokkiEgypt Departamento de Química Universidade Federal do Rio Grande do NorteCx.Postal 166459078-970 NatalRio Grande do NorteBrasil Instituto de Química Universidade Estadual de CampinasBrasil Chemistry Department Faculty of ScienceTaif UniversityP.O.Box 888Al-HawiahTaif 21974Saudi Arabia Department of Chemistry Faculty of SciencePort SaidPort Said UniversityEgypt

In this work,we have reported the synthesis and spectroscopic characterization of captopril(Cap)coordination compounds:Cu(Cap)·2H 2O,Cr(Cap)·H 2O,Zn(Cap)·3H 2O and Mg(Cap)***,it is worthily mentioned that the FTIR spectroscopic technique was employed to recognized the nature of coordination between captopril ligand and copper,chromium,zinc and magnesium(Ⅱ)metal *** view of the infrared spectroscopic tool,the copper(Ⅱ)metal ion coordinated toward captopril drug ligand through sulfur atom of SH group dependent on the absent of stretching vibration band of—*** on this result,the stretching motion ofνa(COO)shifts clearly indicates that Cu 2+,Cr 2+,Zn 2+and Mg 2+the carboxylic group is employed as coordinative site for all compounds as a metal-ligand coordinative *** a general behavior,it is verified that the coordination compound thermal stability(considering the release of captopril molecules,not the release of water molecules)is affected by the metal cation radius:minor radius is associated with higher thermal stability,probably due to a higher metal-captopril bond dissociation enthalpy.

关键词： Captopril Transition metals Spectroscopy Coordination compounds thermogravimetry

Thermogravimetric study of combustion of biomass and anthracite coal by iso-conversional method

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Journal of Iron and Steel Research International 2018年第3期25卷 330-339页

作者： Dong Wang Si-yi Luo Yang-min Zhou Chui-jie Yi National and Local Joint Engineering Research Center of Metallurgical Slag Efficient Resource Utilization QingdaoTechnological University Qingdao 266520 Shandong China

The combustion characteristics of biomass, anthracite coal and their blends were investigated using thermogravimetry, and the kinetic parameters and combustion reaction mechanisms were tested by combining the iso-conversional method and Avrami method in order to find out the kinetics characteristics responsible for the combustion of samples. In biomass combustion, two peaks were observed at 332.3 and 472.3℃, but the reactive rate curve of coal showed one peak with maximum mass loss rate at 552.8℃. The ignition temperature and burnout temperature of blends decreased, and the ignition index and combustibility index increased with the increase in biomass content. Calculation of kinetic parameters showed that the values of activation energy of blends increased with increasing biomass content from 150.77 to 215.93 kJ/mol. The reaction orders of blends lay in the range of 0.44 and 0.78.

关键词： Biomass-Pulverized coal Combustion-Kinetics thermogravimetry Iso-conversional method