Application of a nonisothermal thermogravimetric method to the kinetic study of the reduction of metallic oxides: Part II. A theoretical treatment of powder bed reduction and its application to the reduction of tungsten oxide by hydrogen

1993 ◽  
Vol 24 (3) ◽  
pp. 475-480 ◽  
Author(s):  
J. A. Bustnes ◽  
D. U. Sichen ◽  
S. Seetharaman
Keyword(s):  
Kinetic Study ◽  
Tungsten Oxide ◽  
Theoretical Treatment ◽  
Thermogravimetric Method ◽  
Powder Bed ◽  
Metallic Oxides

Kinetic study on preparation of substoichiometric tungsten oxide WO2.72 via hydrogen reduction process

2018 ◽  
Vol 137 (2) ◽  
pp. 389-397 ◽  
Author(s):  
Dan Qiao ◽  
Yue Wang ◽  
Fan Li ◽  
Daya Wang ◽  
Baijun Yan
Keyword(s):  
Kinetic Study ◽  
Tungsten Oxide ◽  
Hydrogen Reduction ◽  
Reduction Process

scholarly journals Study of thermal behavior of phytic acid

2013 ◽  
Vol 49 (2) ◽  
pp. 275-283 ◽  
Author(s):  
André Luis Máximo Daneluti ◽  
Jivaldo do Rosário Matos
Keyword(s):  
Thermal Decomposition ◽  
Thermal Behavior ◽  
Mass Loss ◽  
Kinetic Study ◽  
Phytic Acid ◽  
Absorption Spectroscopy ◽  
Elemental Analysis ◽  
Reaction Order ◽  
Dehydration Process ◽  
Thermogravimetric Method

Phytic acid is a natural compound widely used as depigmenting agent in galenic cosmetic emulsions. However, we have observed experimentally that phytic acid, when heated to 150 ºC for around one hour, shows evidence of thermal decomposition. Few studies investigating this substance alone with regard to its stability are available in the literature. This fact prompted the present study to characterize this species and its thermal behavior using thermal analysis (TG/DTG and DSC) and to associate the results of these techniques with those obtained by elemental analysis (EA) and absorption spectroscopy in the infrared region. The TG/DTG and DSC curves allowed evaluation of the thermal behavior of the sample of phytic acid and enabled use of the non-isothermal thermogravimetric method to study the kinetics of the three main mass-loss events: dehydration I, dehydration II and thermal decomposition. The combination of infrared absorption spectroscopy and elemental analysis techniques allowed evaluation of the intermediate products of the thermal decomposition of phytic acid. The infrared spectra of samples taken during the heating process revealed a reduction in the intensity of the absorption band related to O-H stretching as a result of the dehydration process. Furthermore, elemental analysis results showed an increase in the carbon content and a decrease in the hydrogen content at temperatures of 95, 150, 263 and 380 °C. Visually, darkening of the material was observed at 150 °C, indicating that the thermal decomposition of the material started at this temperature. At a temperature of 380 °C, thermal decomposition progressed, leading to a decrease in carbon and hydrogen. The results of thermogravimetry coupled with those of elemental analysis allow us to conclude that there was agreement between the percentages of phytic acid found in aqueous solution. The kinetic study by the non-isothermal thermogravimetric method showed that the dehydration process occurred in two stages. Dehydration step I promoted a process of vaporization of water (reaction order of zero), whereas dehydration step II showed an order of reaction equal to five. This change in reaction order was attributed to loss of chemically bonded water molecules of phytic acid or to the presence of volatile substances. Finally, the thermal decomposition step revealed an order of reaction equal to one. It was not possible to perform the kinetic study for other stages of mass loss.

scholarly journals Kinetic Study of the Catalytic Pyrolysis of Oil-Containing Waste

2016 ◽  
Vol 11 (3) ◽  
pp. 330 ◽  
Author(s):  
Kirill Chalov ◽  
Yury Lugovoy ◽  
Yury Kosivtsov ◽  
Mikhail Sulman ◽  
Esther Sulman ◽  
...  
Keyword(s):  
Experimental Data ◽  
Kinetic Study ◽  
Catalytic Pyrolysis ◽  
Reaction Engineering ◽  
Catalyst Loading ◽  
Kinetic Investigation ◽  
Optimal Conditions ◽  
Optimal Parameters ◽  
Pyrolysis Process ◽  
Thermogravimetric Method

<p>Basing on the experimental data the optimal parameters of the pyrolysis of heavy and residual hydrocarbons of oil were defined as follows: temperature of 500 °С; catalyst  of CoCl<sub>2</sub> with the catalyst loading 5% (wt.) of the substrate weight. Under the optimal conditions the kinetic investigation of the pyrolysis process was carried out using the thermogravimetric method. According to the investigation, it was found that the activation energy of the catalytic pyrolysis of oil-containing waste decreased by 20-30 kJ/mol in comparison to non-catalytic process. Copyright © 2016 BCREC GROUP. All rights reserved</p><p><em>Received: 13<sup>th</sup> July 2015; Revised: 25<sup>th</sup> March 2016; Accepted: 1<sup>st</sup> April 2016</em></p><p><strong>How to Cite:</strong> Chalov, K., Lugovoy, Y., Kosivtsov, Y., Sulman, M., Sulman, E., Matveeva, V., Stepacheva, A. (2016). Kinetic Study of the Catalytic Pyrolysis of Oil-Containing Waste. <em>Bulletin of Chemical Reaction Engineering &amp; Catalysis</em>, 11 (3): 330-338 (doi:10.9767/bcrec.11.3.572.330-338)</p><p><strong>Permalink/DOI:</strong> <a href="http://doi.org/10.9767/bcrec.11.3.572.330-338">http://doi.org/10.9767/bcrec.11.3.572.330-338</a></p>

Mixed ionic electronic conducting powder bed for grid level energy storage and release: A study of tungsten oxide reduction kinetics

2015 ◽  
Vol 40 (9) ◽  
pp. 3624-3632 ◽  
Author(s):  
Jarrod D. Milshtein ◽  
Diana R. Gergel ◽  
Soumendra N. Basu ◽  
Uday B. Pal ◽  
Srikanth Gopalan
Keyword(s):  
Energy Storage ◽  
Tungsten Oxide ◽  
Reduction Kinetics ◽  
Level Energy ◽  
Oxide Reduction ◽  
Powder Bed ◽  
Grid Level

Kinetic study of the partial hydrogenation of 1-heptyne on tungsten oxide supported on alumina

2012 ◽  
Vol 87 (11) ◽  
pp. 1521-1528 ◽  
Author(s):  
María Maccarrone ◽  
Gerardo Torres ◽  
Cecilia Lederhos ◽  
Juan Badano ◽  
Carlos Vera ◽  
...  
Keyword(s):  
Kinetic Study ◽  
Tungsten Oxide ◽  
Partial Hydrogenation

Contrasts of planar defects in reflection electron microscopy

1993 ◽  
Vol 51 ◽  
pp. 1004-1005
Author(s):  
Feng Tsai ◽  
J. M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Surface Defects ◽  
Practical Importance ◽  
Theoretical Treatment ◽  
Crystal Surfaces ◽  
Planar Defects ◽  
Surface Steps ◽  
Surface Reconstructions ◽  
Domain Boundaries ◽  
Reflection Electron Microscopy

Reflection electron microscopy (REM) has been used to study surface defects such as surface steps, dislocations emerging on crystal surfaces, and surface reconstructions. However, only a few REM studies have been reported about the planar defects emerging on surfaces. The interaction of planar defects with surfaces may be of considerable practical importance but so far there seems to be only one relatively simple theoretical treatment of the REM contrast and very little experimental evidence to support its predications. Recently, intersections of both 90° and 180° ferroelectric domain boundaries with BaTiO3 crystal surfaces have been investigated by Tsai and Cowley with REM.The REM observations of several planar defects, such as stacking faults and domain boundaries have been continued by the present authors. All REM observations are performed on a JEM-2000FX transmission electron microscope. The sample preparations may be seen somewhere else. In REM, the incident electron beam strikes the surface of a crystal with a small glancing angle.

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