Pyrolysis of the hybrid energy cane: thermal decomposition and kinetic modeling using non-isothermal thermogravimetric analysis

Journal of Thermal Analysis and Calorimetry - This work aims to investigate the thermal decomposition and reaction kinetics of the hybrid energy cane, as well as its thermochemical properties....     

Kinetic analysis of DSC and thermogravimetric data on combustion of lignite

Thermal analysis increasingly being used to obtain kinetic data relating to sample decomposition. This work involves a comparative study of several methods used to analyse DSC and TG/DTG data obtained on the oxidation of Beypazari lignite. A general computer program was developed and the methods are compared with regard to their accuracy and the ease of interpretation of the kinetics of thermal decomposition. For this study, the ratio method was regarded as the preferred method, because it permits the estimation of reaction order, activation energy and Arrhenius constant simultaneously from a single experiment.The experimental part of this research was supported in part by NATO-SFS Project TU-Energy II. The authors express their appreciation to the NATO-SFS program for providing financial support for this project.     

The non-isothermal thermogravimetric tests of animal bones combustion. Part. I. Kinetic analysis

The non-isothermal combustion of animal bones was investigated by simultaneous thermogravimetric and differential thermal analysis (TG–DTA), in the temperature range ΔT = 20–650 °C. The full kinetic triplet (A, E_a and f(α)) for the investigated process was established, using different calculation procedures: isoconversional (model-free) and the Kissinger's methods. The non-isothermal process occured through three reaction stages (I, II and III). Stage I was described by a reaction model, which contains two competing reactions with different values of the apparent activation energy. The autocatalytic two-parameter Šesták–Berggren (SB) model (conversion function f(α) = α^0.62(1 − α)^3.22), best described the second (II) reaction stage of bone samples. This stage, which corresponds to the degradation process of organic components (mainly collagen), exhibited the autocatalytic branching effect, with increasing complexity. Stage III, attributed to the combustion process of organic components, was best described by an n-th reaction order model with parameter n = 1.5 (f(α) = (1 − α)^1.5). The appearance of compensation effect clearly showed the existence of three characteristic branches attributed to the dehydration, degradation and combustion processes, respectively, without noticable changes in mineral phase. The isothermal predictions of bone combustion process, at four different temperatures (T_iso = 200, 300, 400 and 450 °C) were established in this paper. It was concluded that the shapes of the isothermal conversion curves at lower temperatures (200–300 °C) were similar, whereas became more complex with further temperature increase due to organic phase degradation.     

扎赉特旗油砂在氮气气氛下的热解制油研究

油砂是一种含有沥青或其他重质石油的沉积岩,主要用于提取油砂沥青,以生产合成原油。中国拥有相当数量的油砂资源,目前还未开采,仅处于初步研究阶段。加拿大在20世纪初期就展开了油砂的开采及制油研究工作,并于20世纪70年代由加拿大合成油公司实现了工业化生产。油砂生产的沥青和合成油已占其石油总产量的1／4以上。     

Kinetic analysis of sequence of two consecutive reactions from thermogravimetric data under non-isothermal conditions. I. Calculated thermograms

This paper suggests a method of drawing the thermogram of a sequence of two consecutive, partially overlapping processes of a given order, run under non-isothermal conditions.     

Kinetic analysis of thermogravimetric data

Four many curves methods, viz. calculation techniques based on Eqs (30), (31), (34) and (36), respectively, for deriving kinetic parameters from several TG curves recorded with different heating rates are tested on two sets of theoretical TG curves. The maximum reaction rate temperature and conversion, as well as the approximate formulae used for their calculation are discussed. Some aspects of the kinetic compensation effect are analysed. The final conclusion is that the use of the many curves methods is not reasonable.     

Kinetic analysis of thermogravimetric data

Fifteen thermogravimetric curves of the thermal decomposition of CaCO₃ reported in the literature have been analysed and kinetic parameters have been derived by means of Coats and Redfern's method. The activation energy varies between 26 and 377 kcal/mole, and the pre-exponential factors between 10² and 10⁶⁹, as functions of the working conditions. The kinetic compensation effect has been observed, and the results are well described by the following empirical compensation law: logZ=0.195E? 1.86.     

Kinetic analysis of thermogravimetric data

Thermal decomposition of 6 complexes of the type AH[Cr(NCS)₄ (am)₂]· nH₂O is studied with derivatograph. The formation of Cr(NCS)₃ as a labile intermediate is presumed. For some decomposition stages kinetic parameters are derived. The kinetic compensation effect is discussed.     

Kinetic analysis of thermogravimetric data

Computer programs are given in Fortran language for three integral methods of deriving kinetic parameters from TG curves. Method 1 is a computerized variant of Doyle's curve-fitting method and performs the calculation of the exponential integralp(x) by means of author's empirical formula. Methods 2 and 3 are variants of the Coats-Redfern linearization method. Testing of the methods on both theoretical and experimental TG curves shows them to be almost equivalent as far as the results obtained are concerned, but Method 1 needs a ten-fold higher computer time.     

Kinetic analysis of thermogravimetric data

Journal of Thermal Analysis and Calorimetry - The thermal decomposition rates of seven [CoX 2(amine)2] type complexes (amine=aromatic amines) have been studied by thermogravimetry at 3 different...     

Kinetic analysis of thermogravimetric data

Nineteen salts of hexachloroplatinic acid with monovalent metals, aromatic and heterocyclic amines and phosphine were obtained and characterized by chemical analysis. The thermal decomposition of these complexes was studied by means of derivatograph and differential scanning calorimetry. The nature of the pyrolysis processes is discussed. From the TG curves, kinetic parameters were derived for different stages of the thermal decompositions.     

Kinetic analysis of thermogravimetric data

The potassium, ammonium and thirteen amine salts of hexabromoplatinic acid were obtained and characterized by chemical analysis. The thermal decompositions of these complex salts were studied by derivatograph and differential scanning calorimetry. The natures of the pyrolysis processes are discussed and compared with those obtained for the analogous chlorocomplexes. From the TG curves, kinetic parameters were derived for different stages of the thermal decomposition.

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Zusammenfassung Es wurden die Kalium-, Ammonium- und dreizehn verschiedene Aminsalze von Hexabromoplatinsäure hergestellt und mittels Elementaranalyse charakterisiert. Mittels Derivatographie und DSC wurde die thermische Zersetzung dieser Komplexsalze untersucht. Das Wesen der Pyrolysevorgänge wird besprochen und mit dem der analogen Chlorokomplexe verglichen. Anhand der TG-Kurven wurden für verschiedene Schritte der thermischen Zersetzung kinetische Parameter ermittelt.

     

A computer program system for kinetic analysis of non-isothermal thermogravimetric data: I. Data acquisition and preparation for kinetic analysis

FORTRAN software is described which enables the generation of rate of weight change data (DTG) from percentage weight change measurements (TG), obtained under non-isothermal conditions. The program also transposes this information into the dimensionless extent and rate of reaction at unit temperature intervals by means of a cubic spline interpolation. A simple search routine identifies all DTG spikes in the thermogravimetric record, and the temperature and extent of reaction at which the rate attains its maximum value. This total information serves as input data for the kinetic analysis software to be discussed in part II of this communication. An example of the application of this program to the pyrolysis of bituminous coal is presented.     

Kinetic analysis of thermogravimetric data XVI

The influence of the sample weight and the heating rate upon the thermal deamination of [Co(niox · H)₂(pyridine)₂]I(I), [Co(niox · H)₂(aniline)₂]I (II) and [Co(niox · H)₂ (pyridine)₂] NCS · 1.5 H₂O (III) and upon the dehydration of (III) has been studied (niox · H₂ stands for nioxime: 1,2-cyclohexanedione dioxime). Kinetic parametersn, E andZ have been derived by means of the authors' three computerized integral methods. Analysis of the results shows method 1 to be equivalent to method 2 with respect to the numerical values obtained, but it needs a tenfold computer time. Method 3 gives better results due to the better choice of input data. The influence of the working conditions and of the chemical constitution upon the kinetic parameters, as well as the kinetic compensation effect, are discussed.

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Zusammenfassung Der Einfluss des Probengewichts und der Aufheizgeschwindigkeit auf die thermische Desaminierung von [Co(niox · H)₂(pyridin)₂]I (I), [Co(niox · H)₂(anilin)₂]I (II) und [Co(niox · H)₂(pyridin)₂]NCS · 1.5 H₂O (III) sowie auf die Dehydratisierung von (III) wurde untersucht (niox · H₂ bedeutet Nioxim: 1,2-cyclohexandion-dioxim). Die kinetischen Parametern, E undZ wurden mit Hilfe der drei komputerisierten Integralmethoden der Autoren abgeleitet. Die Analyse der Ergebnisse zeigt, da\ Methode 1 der Methode 2 hinsichtlich der erhaltenen numerischen Werte ebenbürtig ist, doch eine zehnfache Rechenzeit beansprucht. Methode 3 ergibt bessere Resultate dank der besseren Wahl der eingegebenen Daten. Der Einfluss der Arbeutsbedingungen und der chemischen Struktur auf die kinetischen Parameter, sowie der kinetische Kompensationseffekt werden diskutiert.

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Résumé On a étudié l'influence du poids de l'échantillon et de la vitesse de chauffage sur la désamination thermique de [Co(niox · H)₂(pyridine)₂]I (I), [Co(niox · H)₂(aniline)₂]I (II) et [Co(niox · H)₂(pyridine)₂]NCS · 1.5 H₂O (III) ainsi que sur la déshydratation de (III) (niox · · H₂ représente la nioxime: 1,2-cyclohexanedione dioxime). A l'aide des trois méthodes d'intégration sur ordinateur des auteurs, les paramètres cinétiquesn, E et Z ont pu Être déduits. L'analyse des résultats montre que la méthode est équivalente à la méthode 2 quant aux valeurs numériques obtenues; elle exige cependant dix fois plus de temps d'ordinateur. La méthode 3 donne de meilleurs résultats en raison de la meilleure sélection des données d'entrée. On discute l'influence des conditions de travail et de la structure chimique sur les paramètres cinétiques ainsi que l'effet de compensation cinétique.

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[(. )₂ ( I (I), [(. )₂ ()₂] I (II) [Co(.)₂ ( NCS. 1.5 H₂O (III), ( .)₂ — : 1.2-. . , , , , E.Z. , 1 2 , . 3 , . , .

     

A computer program system for kinetic analysis of non-isothermal thermogravimetric data: II. Generalized kinetic analysis and application to coal pyrolysis

A FORTRAN program is presented which enables the kinetic analysis of extent and rate of reaction data resulting from transposed experimental TG/DTG data obtained under non-isothermal conditions. This software allows one to perform Arrhenius, Friedman and Kissinger analyses for up to nine different solid-state rate-controlling reactions, including nth order, Avrami-Erofeev, phase boundary movement and diffusional models. Data from an investigation of the pyrolysis of a bituminous coal serve as an example of the application of the program.     

Thermal analysis of coals,oil shales and oil sands

Instances where differential scanning calorimetry and thermogravimetry have been applied to the study of coals, oil shales and oil sands are reviewed. Work carried out in this laboratory and model studies culled from the literature are used as examples to illustrate a particular application. The topics covered include characterization, assay, thermal stability determination and simulation of processing conditions.     

High-speed thermogravimetric analysis of the combustion of wood and Ca-rich fuel

Journal of Thermal Analysis and Calorimetry - Due to the increasing environmental concerns, the use of fossil fuels is being reduced. In search of less polluting ways of energy production,...     

Kinetic analysis of thermogravimetric data,III

Doyle's isothermal method is analysed by using it for deriving activation energies from theoretical curves. Empirical formulae are given for the time correctiont _c, as well as for the factorr in the following equation:E _a=?rm cal/mole. An iterative procedure is suggested, which eliminates the inaccuracy of Doyle's method and permits the derivation of activation energies with an accuracy of ±0.1 kcal/mole in ideal cases.     

热重法研究煤的燃烧反应及其动力学

我国是个多煤少油的国家,煤炭是我国的主要能源,在我国的一次能源中所占比列高达70%[1].煤炭被广泛用于人类生产与生活的各个方面,且它的利用主要是通过燃烧直接获得能量.然而由于先进技术的欠缺,我国在煤炭的利用中一直存在着燃烧效率不高和环境污染严重等缺点,这与现今能源短缺和环境保护日益受重视的现状不相适应.本文通过研究分析煤的燃烧反应及燃烧反应动力学,为煤炭在利用时燃烧的清洁化与高效化提供科学依据.