Kinetic Study Of Thermal Decomposition Research Articles

Kinetic study of thermal decomposition of sugarcane bagasse pseudo-components at typical pretreatment conditions: Simulations of opportunities towards the establishment of a feasible primary biorefining

A deeper understanding of the kinetic and thermodynamic parameters of thermal degradation of sugarcane bagasse (SCB) is fundamental to defining appropriate conditions for primary biorefining in the production of renewable fuels. In this work, the kinetics of thermal degradation of high polymers of SCB was investigated through thermogravimetric data. Model-free and model-fitting methods were used to calculate apparent activation energies (Ea) and other related reaction parameters. An essential advance of this work is related to the quantitative interpretation of the degradation process (an endothermic and non-spontaneous process) via a multi-stage model governed by diffusion-controlled reactions and order-based models, which helps explain the differences observed in the mass balance of biorefining processes. Based on derivative thermogravimetric curves, three major peaks were associated with pseudo-components (PSE): PSE 1 (hemicelluloses + extractives and lignin), PSE 2 (cellulose + extractives and lignin), and PSE 3 (lignin + extractives and residual holocellulose). For PSE 1, PSE 2, and PSE 3, respectively, Ea ranges of 124–154, 147–153, and 230–530 kJ⋅mol−1 were obtained using the Kissinger-Akahira-Sunose method, and 120–152, 144–150, and 232–545 kJ⋅mol−1 were obtained using the Flynn-Wall-Ozawa method. These data support the calculation of many critical operating parameters of biorefinery processes, such as the minimum pretreatment temperature. SCB biorefining could lead to a degradation of up to 10, 0.5, and 11% of PSE 1, PSE 2, and PSE 3, respectively, at 473.15 K for 200 min.

Valorisation of biomass pellets to renewable fuel and chemicals using pyrolysis: characterisation of pyrolysis products and its application

ABSTRACTThe pyrolysis of biomass (agro and garden waste) pellets in the temperature range of 200–600°C is studied in the present work. The pyrolysis of biomass pellets in a batch reactor generates mainly CO2 and CO gases at 300°C and H2 gas along with C1-C3 hydrocarbons at 600°C. The yield of non-condensable gases, liquid products and biochar was 30, 38 wt.% (30 wt.% bio-oil, 8 wt.% water), and 32 wt.%, respectively. The MS analysis of the bio-oil depicted the presence of light oxygenates, furans, anhydrosugars, and phenolic compounds. The biochar showed porous and macrostructure with various surface functional groups. A kinetic study of thermal decomposition of biomass pellets was performed along with a reaction mechanism of the product formation during the pyrolysis. Net energy return calculations depicted that the pyrolysis system can be self-sustained. The present study demonstrates the possible conversion of biomass pellets into useful products such as acids, aldehydes, phenolic compounds and carbonaceous char.

An experimental and kinetic study of thermal decomposition of phenanthrene.

Polycyclic aromatic hydrocarbons (PAHs) have enormous potential hazards. It is necessary for China to propose more internationally stricter standards for PAHs, in order to improve the country's pollutant prevention and control policy system, and ultimately, provide institutional guarantees for implementing PAH emissions prevention and control. In this study, phenanthrene, a typical PAHs generated during municipal solid waste (MSW) to energy system, was applied as a model compound to study the thermal degradation mechanism during the combustion process. Combustion kinetics for the three major gaseous products, including hydrogen, methane, and carbon dioxide, were determined. Experimental results indicated that hydrogen was promoted compared to methane and carbon dioxide during the combustion of phenanthrene, especially in high oxygen concentrations. The apparent activation energy (Ea) of 8.299-11.51, 13.10-23.07, and 9.368-15.29 kJ/mol, pre-exponential factor (A) of 0.219-1.579, 5.034-10.12, and 6.553-15.51 s-1, and the reaction order (n) of 1.160-1.234, 1.059-1.305, and 1.636-1.774 were obtained for hydrogen, methane, and carbon dioxide, respectively. Research on combustion behavior of phenanthrene and reaction kinetics provides the theoretical basis for the high-temperature removal of PAHs as byproducts during the combustion of MSW in oxygen-rich atmosphere.

Kinetic study of thermal decomposition of new Eu(III), Tb(III) and Gd(III) complexes with beta-diketone ligands and 4,4-diphenyl-2,2-dipyridyl, chloride of 1,10-phenantrolinium

Complexes of general formula [Eu(fod)3·L], [Tb(fod)3·L] and [Gd(fod)3·L] (where fod=6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octadionate; L=4,4-diphenyl-2,2-dipyridyl or/and chloride of 1,10-phenantrolinium) were synthesized by reacting the corresponding salt of terbium and gadolinium with β-diketone(fod) and other ligands, and the precursor Eu(fod)3·2H2O with diphenylbipy and phenCl ligands. The thermal decomposition of these complexes along with description of some emitting materials is discussed in details. We focused on those complexes emitting in the visible region, which can be used in lighting industry (e.g., for the preparation of photo- and electro-luminescent devices) and for biological immunoassays. The thermal decompositions of Eu(fod)3·L, Tb(fod)3·L and Gd(fod)3·L are best described by R2 and R3 kinetic models. Some selected results of our work concerning the synthesis of highly luminescent complexes for application in lighting and light conversion technologies are reported. Such materials have been obtained by combining the peculiar luminescence properties of Eu3+ and Tb3+ antenna complexes with β-diketone (fod).

Characterization of depolymerized residues from extremely low acid hydrolysis (ELA) of sugarcane bagasse cellulose: Effects of degree of polymerization, crystallinity and crystallite size on thermal decomposition

Sugarcane bagasse cellulose was subjected to the extremely low acid (ELA) hydrolysis in 0.07% H2SO4 at 190, 210 and 225°C for various times. The cellulose residues from this process were characterized by TGA, XRD, GPC, FTIR and SEM. A kinetic study of thermal decomposition of the residues was also carried out, using the ASTM and Kissinger methods. The thermal studies revealed that residues of cellulose hydrolyzed at 190, 210 and 225°C for 80, 40 and 8min have initial decomposition temperature and activation energy for the main decomposition step similar to those of Avicel PH-101. XRD studies confirmed this finding by showing that these cellulose residues are similar to Avicel in crystallinity index and crystallite size in relation to the 110 and 200 planes. FTIR spectra revealed no significant changes in the cellulose chemical structure and analysis of SEM micrographs demonstrated that the particle size of the cellulose residues hydrolyzed at 190 and 210°C were similar to that of Avicel.

A kinetic study of thermal decomposition of glycidyl azide polymer (GAP)-based energetic thermoplastic polyurethanes

Energetic thermoplastic polyurethane elastomers (ETPUs) of glycidyl azide polymer (GAP) were synthesized on GAP/poly(caprolactone)(PCL) (100/0, 50/50) as a soft segment and methylenebis(phenylisocyanate) (MDI) extended 1,5-pentanediol as a hard segment by solution polymerization in dimethyl formamide (DMF). Differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA) were used to examine the thermal decomposition behavior. Kinetic analysis was performed with model fitting and a model-free method to obtain the activation energy as a function of the extent of conversion. ETPU decomposition was divided into two stages with different activation energies. The first main weight loss step corresponds to the elimination of N2 from the decomposition of -N3 bonds within azide polymers. The activation energy of the main decomposition of GAP ETPU and GAP/PCL ETPU was approximately 190 kJ/mol. The second weight loss step coincides with the decomposition of the skeleton. The activation energy of those showed an increasing trend.

Effect of thermal dehydration and rehydration on Na-magadiite structure

The effect caused by dehydration and rehydration of the synthetic Na-magadiite was investigated by TGA, XRD, SEM, and 29Si NMR. Thermal analysis of Na-magadiite presented two well-defined loss mass stages between 20 and 150 °C and another between 270 and 310 °C, both related to the removal of interlayer water. The swelling behavior of Na-magadiite was studied by thermal dehydration data obtained at 150 and 300 °C, and respective rehydration by water addition. X-ray patterns showed that the dehydration of Na-magadiite at 150 and 300 °C provoked the basal spacing decrease. The XRD also showed that only the material treated at 150 °C returned to the original structure with the rehydration. 29Si NMR spectra showed that after rehydration, the Q 3/Q 4 relationship presented the same value for Na-magadiite treated at 150 °C. However, this Q 3/Q 4 value decreased when the treatment was done at 300 °C. Kinetic studies of thermal decomposition showed that the dehydration of magadiite is based on a phase boundary-controlled reaction, caused by contracting areas. The exfoliation of lamellas with thermal treatment can explain this behavior, as observed in SEM images.

Spectral and kinetic studies of thermal decomposition of complexes of biologically active glutathione with ZnII and CdII ions

The Zn I I and Cd I I complexes of reduced glutathione (GSH) of general composition [M(L)(X)].nH 2 O (where LH 2 = GSH; X = Cl - , NO - 3 /CH 3 CO - 2 , and n = 1-2) have been synthesized and characterized by elemental analysis, infrared spectra, electronic spectra and thermal studies. The complexes were found to be monomer and involved coordination through cystein sulphur and carboxylate oxygen giving tetrahedral geometry. From thermogravimetric (TG) studies, order of the reaction, mass loss and apparent activation energy have been calculated and from differential thermal analytical studies, heat of reaction has been measured. Thermodynamic activation parameters have been calculated.

Kinetic studies of thermal decomposition of AANTO, BAED and DAAP by ARC and DSC

In this paper, three new organic azids i.e. 2-azidoethylammonium-3-nitro-1,2,4-triazol-5-onate (AANTO), 1,1-dinitro-3-aza-5-azidopentane (DAAP) and bis (2-azidoethylamine)-ethyl-dinitramine (BAED) are synthesized and characterized, and their thermal decomposition reactions are studied using DSC and ARC. The approximate heat of decomposition is determined, and the the self-heating rates and pressure increasing rates are measured as the function of self-heating temperature. Their thermal stability is compared, and their potential thermal hazard is assessed.

Kinetic Study of Thermal Decomposition of the DMIT Complex of Cobalt

In this work, a cobalt complex with dmit (1,3-dithiol-2-thione-4,5-dithiolate) as ligand was prepared and its thermal stability was studied by thermogravimetric analysis and kinetics by means of the Zsako method and a non-linear method. For both methods, numerical binomial and polynomial filters were used, where points in the central interval were utilized.

New kinetic model for thermal decomposition of heterogeneous materials

In the kinetic studies of thermal decomposition of lignocellulosic materials using dynamic TG, relationships between the biomass fraction ``w`` and the time ``t`` of the form dw/dt = {minus}k(w {minus} w{sub {infinity}}){sup n} are usually admitted, and the residue fraction at infinite time (w{sub {infinity}}) is considered constant. However, in heterogeneous solids such as lignocellulosic materials, the different polymers decompose at different temperatures, and so the value of w{sub {infinity}} is not constant, Therefore, the previous equation must be considered approximate. To illustrate this feature, experiments with kraft lignin, which decomposes in an interval of temperatures between 150 and 750 C, have been carried out. A kinetic model is proposed, bearing in mind that there is a maximum pyrolyzable fraction at each temperature. This model considers that the thermal decomposition of a heterogeneous material occurs through a great number of reactions and that at a given temperature only some fractions can decompose. The kinetic parameters (activation energy and preexponential factor) can change during the decomposition process as function of the reactions taking place. Under some assumptions, it is deduced that this model is equivalent to assume the kinetic law dw/dt = {minus}k(w{minus}w{sub {infinity}}) for first-order reaction, where the residue yieldmore » w{sub {infinity}} is a function of the temperature.« less

Kinetic study of thermal decomposition of dolomite by controlled transformation rate thermal analysis (CRTA) and TG

The mechanism of the thermal decomposition of dolomite was studied. It was shown that a comparison of the kinetic data obtained from the kinetic analysis of a single TG trace and a single curve recorded using the constant rate thermal analysis (CRTA) method allows discrimination of the actual kinetic model obeyed by the reaction and also determination of its corresponding kinetic parameters.

Kinetic study of thermal decomposition of calcium carbonate in the presence of K2CO3 and BaCO3

Kinetic study of thermal decomposition of calcium carbonate in the presence of K2CO3 and BaCO3

Use of the quartz crystal microbalance for kinetic studies of thermal decomposition of solids

A quartz crystal microbalance has been proposed for studies on the temperature dependence of the linear rate of a reaction interface advance in topochemical reactions of the thermal decomposition of solids. A quartz crystal microbalance has been used in investigations of the CuSO 4 · 5H 2O dehydration. The data agree fairly well with those available in the literature. Advantages and disadvantages of the method proposed are discussed.

Kinetic study of thermal decomposition of benzoyl peroxide in polyamide and degradation of polymer macromolecules

A kinetic analysis was made of the thermal decomposition of benzoyl peroxide in polyamide in inert atmosphere. It was established that the decomposition of peroxide takes place simultaneously by monomolecular and chain mechanisms. Chain decomposition of benzoyl peroxide is induced by polymer macromolecules and the order of the reaction is 1 2 . Thermal decomposition of benzoyl peroxide in polyamide causes decomposition of polymer macromolecules. It was shown that macromolecular rupture does not involve the induced decomposition of peroxide.

Critical examination of several problems typically found in the kinetic study of thermal decomposition under vacuum

After considering several problems peculiar to the kinetics of thermal decompol sition under vacuum (formalism, separation of successive steps, influence of residuapressure and of heat or mass transfers) the author suggests, as a possible answer, the use of constant decomposition rate thermal analysis, in association or not with thermogravimetry or calorimetry. The interest of the method is shown for the following measurements: apparent orders of reaction, energies of activation, differential enthalpies of dissociation. It appears to be specially suited to the study of thermal decomposition under high vacuum.

Kinetic studies of thermal decomposition and substitution reactions of cis-Mo(CO)4[P(C6H5)3](amine) compounds. Competitive study of Lewis bases for the intermediate [Mo(CO)4P(C6H5)3

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTKinetic studies of thermal decomposition and substitution reactions of cis-Mo(CO)4[P(C6H5)3](amine) compounds. Competitive study of Lewis bases for the intermediate [Mo(CO)4P(C6H5)3]Carol L. Hyde and Donald J. DarensbourgCite this: Inorg. Chem. 1973, 12, 6, 1286–1291Publication Date (Print):June 1, 1973Publication History Published online1 May 2002Published inissue 1 June 1973https://doi.org/10.1021/ic50124a015RIGHTS & PERMISSIONSArticle Views236Altmetric-Citations45LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (701 KB) Get e-Alerts Get e-Alerts