scholarly journals Oxidation Behavior and Kinetics Parameters of a Lean Coal at Low Temperature Based on Different Oxygen Concentrations

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 511
Author(s):  
Yu Hao ◽  
Taiping Xie
Keyword(s):  
Low Temperature ◽  
Adsorption Capacity ◽  
Oxidation Behavior ◽  
Volume Fraction ◽  
Precipitation Amount ◽  
Kinetics Parameters ◽  
Temperature Oxidation ◽  
Initial Stage ◽  
Lean Coal ◽  
Oxygen Concentrations

The method of dividing the “three zones” of spontaneous combustion in goaf by oxygen volume fraction is the most widely used and effective method at present. However, the oxygen volume fraction method does not consider the influence of methane concentration in goaf, which is only applicable to low-gas goaf, not high-gassy goaf. In this work, the oxidation behavior and kinetics parameters of a lean coal at low temperatures under five different oxygen concentrations, including methane and its kinetics during low-temperature oxidation, were studied using temperature programming tests and thermogravimetric tests. The results showed that the decrease of oxygen content improves the adsorption capacity of coal to absorb different atmospheres at the initial stage. In the whole reaction process, there is a negative correlation between the strong-to-weak order of exothermicity and adsorption capacity, with a significant increase in apparent activation energy E. A marked hysteresis of the precipitation time of CO and CO2 and a decrease in their precipitation amount and a rise in the initial temperature for the generation of CO and CO2 were found.

Manufacturing and Oxidation Behavior of Silicide-Based Nanocomposite Coatings on Refractory Metals by Displacement Reaction

2007 ◽  
Vol 539-543 ◽  
pp. 135-140
Author(s):  
Jin Kook Yoon ◽  
Dong Wha Kum ◽  
Kyung Tae Hong
Keyword(s):  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Volume Fraction ◽  
Coefficient Of Thermal Expansion ◽  
Crack Density ◽  
Nanocomposite Coatings ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
Reinforcing Particles ◽  
Displacement Reactions

The microstructure and oxidation resistance of MSi2-SiC or MSi2-Si3N4 nanocomposite coatings (M = Mo, W, Nb, Ta) on M substrates formed by displacement reactions between M-carbides or M–nitrides and silicon, respectively, was investigated. Present study demonstrated that the crack density formed in the MSi2-base nanocomposite coatings due to mismatch in the coefficient of thermal expansion between nanocomposite coatings and M substrates could be controlled by adjusting the volume fraction of the SiC or Si3N4 reinforcing particles with the low CTE values. The high- and low-temperature oxidation resistance of nanocomposite coatings was superior to that of monolithic MSi2 coatings.

Effect of NaOH Treatment on the Low-Temperature Oxidation Behavior of Lignite

2019 ◽  
Vol 33 (9) ◽  
pp. 9161-9170 ◽  
Author(s):  
Yongyu Wang ◽  
Sheng Xue ◽  
Yibo Tang ◽  
Fuding Mei ◽  
Wei He ◽  
...  
Keyword(s):  
Low Temperature ◽  
Oxidation Behavior ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
Naoh Treatment

Low temperature oxidation behavior of Mo2BC coatings

2020 ◽  
Vol 38 (2) ◽  
pp. 023403
Author(s):  
Jan-Ole Achenbach ◽  
Soheil Karimi Aghda ◽  
Marcus Hans ◽  
Daniel Primetzhofer ◽  
Damian M. Holzapfel ◽  
...  
Keyword(s):  
Low Temperature ◽  
Oxidation Behavior ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation

Construction of a macromolecular structural model of Chinese lignite and analysis of its low-temperature oxidation behavior

2017 ◽  
Vol 25 (9) ◽  
pp. 1314-1321 ◽  
Author(s):  
Xianliang Meng ◽  
Mingqiang Gao ◽  
Ruizhi Chu ◽  
Zhenyong Miao ◽  
Guoguang Wu ◽  
...  
Keyword(s):  
Low Temperature ◽  
Oxidation Behavior ◽  
Structural Model ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation

scholarly journals Elevated pressure low-temperature oxidation of linear five-heavy-atom fuels: diethyl ether, n-pentane, and their mixture

2020 ◽  
Vol 234 (7-9) ◽  
pp. 1269-1293 ◽  
Author(s):  
Luc-Sy Tran ◽  
Yuyang Li ◽  
Meirong Zeng ◽  
Julia Pieper ◽  
Fei Qi ◽  
...  
Keyword(s):  
Low Temperature ◽  
Diethyl Ether ◽  
Oxidation Behavior ◽  
Heavy Atom ◽  
Fuel Mixture ◽  
Elevated Pressure ◽  
Oxidation Products ◽  
Compression Ignition ◽  
Temperature Oxidation ◽  
Oxidation Chemistry

AbstractDiethyl ether (DEE) has been proposed as a biofuel additive for compression-ignition engines, as an ignition improver for homogeneous charge compression ignition (HCCI) engines, and as a suitable component for dual-fuel mixtures in reactivity-controlled compression ignition (RCCI) engines. The combustion in these engines is significantly controlled by low-temperature (LT) chemistry. Fundamental studies of DEE LT oxidation chemistry and of its influence in fuel-mixture oxidation are thus highly important, especially at elevated pressures. Elevated pressure speciation data were measured for the LT oxidation of DEE, of its similarly-structured linear five-heavy-atom hydrocarbon fuel (n-pentane), and of a mixture of the two fuels in a jet-stirred reactor (JSR) in the temperature range of 400–1100 K and at various pressures up to 10 bar. The pressure influence on the LT oxidation chemistry of DEE was investigated by a comparison of the measured profiles of oxidation products. The results for DEE and n-pentane were then inspected with regard to fuel structure influences on the LT oxidation behavior. The new speciation data were used to test recent kinetic models for these fuels [Tran et al., Proc. Combust. Inst. 37 (2019) 511 and Bugler et al., Proc. Combust. Inst. 36 (2017) 441]. The models predict the major features of the LT chemistry of these fuels well and could thus subsequently assist in the data interpretation. Finally, the LT oxidation behavior of an equimolar mixture of the two fuels was explored. The interaction between the two fuels and the effects of the pressure on the fuel mixture oxidation were examined. In addition to reactions within the combined model for the two fuels, about 80 cross-reactions between primary reactive species generated from these two fuel molecules were added to explore their potential influences.

Growth of Single Crystals and Low Temperature Oxidation Behaviors of MoSi2 and NbSi2

2005 ◽  
Vol 475-479 ◽  
pp. 729-732 ◽  
Author(s):  
Fang Zhang ◽  
Lan Ting Zhang ◽  
Jin Xing Yu ◽  
Jian Sheng Wu
Keyword(s):  
Low Temperature ◽  
Single Crystals ◽  
Oxidation Behavior ◽  
Weight Changes ◽  
Low Temperature Oxidation ◽  
Zone Method ◽  
Temperature Oxidation ◽  
Single Crystalline ◽  
Optical Heating ◽  
Spark Plasma

In this paper, single crystals, around 8mm in diameter, of MoSi2 and NbSi2 have been grown by optical heating floating zone method. X-ray analysis confirmed that the as-grown ingots were single phase and single crystalline material. Oxidation behavior of the poly-crystalline and single crystalline MoSi2 and NbSi2 were characterized by measuring their weight changes as a function of exposure time. For arc-melted poly-crystalline samples, MoSi2 and NbSi2 fully turned into white powders after 160 and 3hrs exposure at 773K and 1023K respectively, which is known as the “pesting” phenomenon. As a comparison, no pesting was found in the dense spark plasma sintered (SPS) poly-crystalline samples and single crystals. The weight change of single crystals during exposure is found to be much lower than that of the SPS sample, indicating grain boundary plays an important role in the low temperature oxidation behavior of these two silicides.

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