Low temperature oxidation of coals

Kaji, Ryuichi; Hishinuma, Yukio; Nakamura, Yoichi

doi:10.1016/0016-2361(85)90413-2

Cited by 106 publications

(42 citation statements)

References 9 publications

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“…These results show that the oxidation reaction of Go coal is controlled by the rate of internal gaseous diffusion. Similar results were reported by Avison et al, 10) Karsner and Perlmutter 11) and Mahajan et al 12) On the other hand, Kaji et al 13) reported that the oxidation rate evaluated by CO 2 and CO formation rates during oxidation was not affected by the coal particle size. One of the reasons for the contradiction may be due to used coal rank.…”

Section: Effect Of Particle Sizesupporting

confidence: 84%

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Oxidation Behavior and Caking Property of Coal under the Atmosphere at Low Oxygen Concentration.

et al. 2003

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Eight coals ranging from bituminous coal to brown coal were oxidized in a thermo-balance or a fixed bed reactor using 5 vol% of oxygen at 100-380°C for 10-400 min. The effects of coal particle size, coal rank, oxidation temperature and oxygen concentration on the oxidation behavior of coal were investigated. The caking property, FT-IR spectrum and pyrolysis behavior of sample oxidized were measured. The oxidation behavior strongly depended on the coal rank. The oxidation reaction of highly caking coal was controlled by the rate of internal gaseous diffusion. The caking property of bituminous coal decreases by the oxidation in the oxidative atmosphere of low oxygen concentration of 5 vol%, which corresponds to that in a flue gas.The aliphatic C-H groups in highly caking coals are easily oxidized during oxidation and remained in coal structure as relatively stable forms. The differences in chemical structure and caking property between the exterior part and the central part of oxidized coal particle was investigated. In the case of highly caking coal, the chemical structure and some properties of oxidized coal depends on the position of the coal particle because the mild oxidation reaction of coal proceeds from the exterior part of coal particle.

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Section: Effect Of Particle Sizesupporting

confidence: 84%

“…It was found that the reaction order with respect to oxygen was 0.97. Kajii et al 13) reported that the oxidation reaction orders with respect to oxygen were 0.5 for CO 2 formation and 0.54 for CO formation, respectively. The observed discrepancy may be due to the difference in used coal type.…”

Section: Effects Of Temperature and Oxygen Concentrationmentioning

confidence: 99%

Oxidation Behavior and Caking Property of Coal under the Atmosphere at Low Oxygen Concentration.

et al. 2003

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“…1-9) and the amount of gases (CO, CO 2 , and H 2 ) emitted during the self-ignition process at the temperature of 323 and 373 K, respectively (parameters nos. [10][11][12][13][14][15]. The HCA allows to effectively investigate the similarity between studied coal samples in the parameters space and the similarities between studied parameters in the objects space.…”

Section: Hierarchical Clustering Analysismentioning

confidence: 99%

Profile of CO2, CO, and H2 Emissions from Thermal Oxidation of Polish Coals

Wojtacha‐Rychter

Smoliński

2020

Materials

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The self-heating phenomenon of coal leads to work safety hazards in underground mining. The quantitative analysis of gaseous products in mine atmosphere constitutes one of the detection methods of advanced coal heating. The article presents the results of tests on CO, CO 2 , and H 2 emissions during simulated heating of coal in the temperature range of 323-523 K. The oxidation of 15 Polish coals of various carbon contents was performed using a flow reactor technique. A chromatography method was applied to measure the changes of oxidation products concentrations with the increase of temperature. It has been determined that all the tested gases were generated at the initial temperature. The collected data indicated that CO 2 was a major oxidation product in the entire temperature range, while the amounts of H 2 produced did not exceed 0.49% volume. At the temperature of 323 K, the ratio of CO 2 /CO was in the range of 10-23 but along with the temperature increase the ratio range narrowed to 3-4. In this paper, a comparison of the physical-chemical properties of the tested coals and the emissions profile of the gases using, among others, the hierarchical clustering analysis showed that samples with higher oxygen, sulfur, and inertinite content as well as lower ash and carbon content formed larger amounts of fire gases.

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“…It is important to mention that Kaji and Hishinuma (1985) shows in his work that the major product of the low-temperature (330 K) oxidation is carbon dioxide. For the overall chemical reaction of dry coal and the chemisorption, respectively, Schmall (1989) referring to Kok (1981) presents the following values of the reaction heat:…”

Section: Mathematical Modelmentioning

confidence: 99%