Reactive adsorption mechanism of O2 onto coal vitrinite during the low temperature oxidation process

Fuel ◽  
2022 ◽  
Vol 308 ◽  
pp. 121802
Author(s):  
Dan Zhou ◽  
Wei Lu ◽  
Jinliang Li ◽  
Yu Song ◽  
Caifang Wu
Keyword(s):  
Low Temperature ◽  
Adsorption Mechanism ◽  
Oxidation Process ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
Reactive Adsorption

Study on the change of organic sulfur forms in coal during low-temperature oxidation process

Fuel ◽  
2018 ◽  
Vol 222 ◽  
pp. 350-361 ◽  
Author(s):  
Lanjun Zhang ◽  
Zenghua Li ◽  
Wenjing He ◽  
Jinhu Li ◽  
Xuyao Qi ◽  
...  
Keyword(s):  
Low Temperature ◽  
Oxidation Process ◽  
Organic Sulfur ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation

Study on Low-Temperature Oxidation Process of Low Rank Coal by In Situ FTIR

2013 ◽  
Vol 652-654 ◽  
pp. 871-876 ◽  
Author(s):  
Xiao Xing Zhong ◽  
Guo Lan Dou ◽  
Hai Hui Xin ◽  
De Ming Wang
Keyword(s):  
Low Temperature ◽  
Functional Groups ◽  
Oxidation Process ◽  
Low Rank ◽  
In Situ Ftir ◽  
Low Rank Coal ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
Low Temperature Process

Low temperature oxidation of two different low rank coals was measured by in-situ FTIR. Curve-fitting analysis was employed to identify functional groups types of raw coals, and series technology was carried out on in-situ infrared spectrum of sample coals at low-temperature oxidation process to analyze the changes of main active functional groups with temperature. The results indicate that -CH3, -CH2, -OH, C=O, COOH are the main active functional groups in low rank coal. In the oxidation process, with temperature increasing, the methyl and methylene show the tendency of increase after decrease and then decrease, and all of hydroxyl, carboxyl and carbonyl group present the tendency of increase after decrease, there exists some differences among the main functional groups in the coal low-temperature process.

Dependence of SiO2/Si interface structure on low-temperature oxidation process

2004 ◽  
Vol 234 (1-4) ◽  
pp. 197-201 ◽  
Author(s):  
T Hattori ◽  
K Azuma ◽  
Y Nakata ◽  
M Shioji ◽  
T Shiraishi ◽  
...  
Keyword(s):  
Low Temperature ◽  
Oxidation Process ◽  
Interface Structure ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation

Neutron Diffraction Study of the Structural Changes Occurring During the Low Temperature Oxidation of UO2

2009 ◽  
Vol 1215 ◽  
Author(s):  
Gianguido Baldinozzi ◽  
Lionel Desgranges ◽  
Gurvan Rousseau
Keyword(s):  
Low Temperature ◽  
Neutron Diffraction ◽  
Uranium Dioxide ◽  
Oxidation Process ◽  
Structural Parameters ◽  
Atomic Scale ◽  
Uranium Oxides ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
Diffraction Patterns

AbstractThe oxidation of uranium dioxide has been studied for more than 50 years. It was first studied for fuel fabrication purposes and then later on for safety reasons to design a dry storage facility for spent nuclear fuel that could last several hundred years. Therefore, understanding the changes occurring during the oxidation process is essential, and a sound prediction of the behavior of uranium oxides requires the accurate description of the elementary mechanisms on an atomic scale. Only the models based on elementary mechanisms should provide a reliable extrapolation of laboratory results over timeframes spanning several centuries. The oxidation mechanism of uranium oxides requires understanding the structural parameters of all the phases observed during the process. Uranium dioxide crystal structure undergoes several modifications during the low temperature oxidation that transforms UO2 into U3O8. The symmetries and the structural parameters of UO2, β-U4O9, β-U3O7 and U3O8 were determined by refining neutron diffraction patterns on pure single-phase samples. Neutron diffraction patterns, collected during the in situ oxidation of powder samples at 483 K were also analyzed performing Rietveld refinements. The lattice parameters and relative ratios of the four pure phases were measured during the progression of the isothermal oxidation. The transformation of UO2 into U3O8 involves a complex modification of the oxygen sublattice and the onset of complex superstructures for U4O9 and U3O7, associated with regular stacks of complex defects known as cuboctahedra which consist of 13 oxygen interstitial atoms. The structural modifications during the oxidation process are discussed.

Micromagnetic Modeling of Magnetite/Maghemite Particles with a Multi-Layer Core-Shelled Structure

2020 ◽  
Vol 1013 ◽  
pp. 9-13
Author(s):  
Kun Peng Ge ◽  
Wyn Williams
Keyword(s):  
Low Temperature ◽  
Geomagnetic Field ◽  
Oxidation Process ◽  
Low Temperature Oxidation ◽  
Dramatic Decrease ◽  
Temperature Oxidation ◽  
The Core ◽  
Uniform Magnetization ◽  
Micromagnetic Modeling ◽  
Highly Uniform

Low temperature oxidized core-shelled magnetite is paramount important in recording geomagnetic field. To characterize the effects of transition zone between the core-shell on the magnetic properties of low temperature oxidation of magnetite, micromagnetic models of hysteresis parameters and microstructures of a multi-layer core-shelled model were systematically investigated by MERRILL (Micromagnetic Earth Related Rapid Interpreted Language Laboratory). Numerical simulations indicate that SD particles (<70 nm) remain highly uniform magnetization, but show decreasing coercivities as oxidation preceeds. For fine SV particles (80 nm to 120 nm), the hysteresis parameters respectively increase and dramatic decrease at the early and late stage of oxidation, and the micromagnetic behaviors vary significantly. Finally the hysteresis parameters of larger SV (>130) particles remain nearly unchanged during oxidation. It indicates that fine SV particles are more sensitive to oxidation, and dominate the dramatic change of experiment observation. Overall, low temperature oxidation of magnetite preferring a multi-layer coupled oxidation process from outside to interior and is capable of recording paleomagnetic signals.

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