Modes and kinetics of CO2 and CO production from low-temperature oxidation of coal

Jie, Wang; Wang, Junfeng; Wu, Jianming; Xue, Sheng; Li, Zhengfeng; Chang, Liping

doi:10.1016/j.coal.2015.01.001

Cited by 101 publications

(33 citation statements)

References 39 publications

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“…Based on the analysis of all 22 coal samples, significant differences in the concentration quotients of the analyzed gases were observed with the changes in the flow rates of synthetic air and nitrogen. Zhang et al (2015) conducted research on carbon oxide emissions for different coal classes at the temperature above 200°C. Based on the impact of coal mass and oxygen consumption on CO 2 and CO emissions during the oxidation reaction, it was noticed that coal oxides are formed as a result of not only the decomposition of surface oxides caused by the reaction but also of the oxygen containing groups in the coal matrix.…”

Section: Resultsmentioning

confidence: 99%

Effect of flow rates of gases flowing through a coal bed during coal heating and cooling on concentrations of gases emitted and fire hazard assessment

Więckowski

Howaniec

Smoliński

2019

Int J Coal Sci Technol

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The flow velocity of gases in gobs directly influences the kinetics and intensity of gaseous components release during heating and cooling of coal. The assessment of fire hazard is performed on the basis of concentrations of particular gases in a mine air. These concentrations differ in coal heating and cooling phase which was proven in the study. This paper presented the results of the experimental study on temperature distribution in a simulated coal bed in heating (50-250°C) and cooling (250-35°C) phases as well as its correlation to variations in concentration of gases released in these phases and flow rates of gases flowing through the coal bed. The research was performed on twenty-two samples of bituminous coals acquired from various coal beds of Polish coal mines. Considerable differences were observed between heating and cooling phases in terms of the concentrations of gases taken into account in calculations of self-combustion index. In the heating phase temperature increase resulted in the decrease of concentrations ratios of ethane, ethylene, propane, propylene and acetylene, while in the cooling phase these ratios increased systemically. The effect of air (in heating phase) and nitrogen (in cooling phase) flow rate on the self-ignition index CO/CO 2 was also determined.

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Section: Resultsmentioning

confidence: 99%

Effect of flow rates of gases flowing through a coal bed during coal heating and cooling on concentrations of gases emitted and fire hazard assessment

Więckowski

Howaniec

Smoliński

2019

Int J Coal Sci Technol

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“…For example (see Figure 4), for coal sample nos. 1,8,9,13, and 15, the growth of carbon monoxide was below 0.15 vol % and the oxygen depletion did not exceed 6.31 vol %, while for the remaining samples the gas growth was over 0.34 vol % and the depletion of oxygen was over 7.81 vol %. Moreover, it was found that for coal sample nos.…”

Section: Oxygen Contentmentioning

confidence: 94%

“…Besides, a larger amount of carbon monoxide and carbon dioxide generated from coal sample nos. 2-5 with high oxygen content (above 9% w/w) may also originate from the decomposition of the active oxygen containing functional groups (i.e., hydroxyls, carboxyls, carbonyls or aldehydes) located in the coal matrix [13,14].…”

Section: Carbon Contentmentioning

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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“…Zhang et al [13] indicated that studying CO and CO 2 kinetics during coal spontaneous combustion is imperative. The kinetics of CO and CO 2 were studied to obtain the surface and inherent reaction regimes of different types of coal during low-temperature oxidation.…”

Section: Introductionmentioning

confidence: 99%

Thermal behavior and microcharacterization analysis of second-oxidized coal

Deng

Zhao

Huang

et al. 2016

J Therm Anal Calorim

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Among coal-producing countries, China has witnessed the highest frequency and severity of coal fires. During mining in the re-mining face and the lower part of the thick coal seam (or coal seam group), second or multiple oxidations of the residual coal can readily occur in mined-out areas, severely increasing the risk of coal fires. The study of multiple oxidations of coal aids in the early detection of spontaneous combustion of remaining coal in the mined-out areas. The characteristics of coal fires are demonstrated using fresh coal samples (first-oxidized coal) and oxidized coal samples (second-oxidized coal) from four different ranks of coals. Proximate and elemental analysis, Fourier transform spectroscopy, and thermogravimetry-differential scanning calorimetry were adopted to investigate the quality, microcharacteristics, characteristic temperatures, and apparent activation energy of second-oxidized coal. In addition, the effect of spontaneous combustion at heating rates of 5.0, 10.0, and 15.0°C min -1 was studied. Compared with the four samples of first-oxidized coal, those of second-oxidized coals cause fire easily under the same conditions. List of symbolsA, A k Pre-exponential factor (s -1 ) A ad Ash content in air-dried basis (%) bHeating rate (°C min -1 ) C daf C content of air-dried basis (%) da/dt Conversion rate (s -1 ) E a , E k Apparent activation energy (kJ mol -1 ) f(a)Function of degree of conversion (dimensionless) H daf H content of air-dried basis (%) M ad Moisture in air-dried basis (%) N daf N content of air-dried basis (%) R Universal gas constant (8.314 J mol -1 K -1 ) r Correlation coefficient (dimensionless) O daf O content of air-dried basis (%) S daf S content of air-dried basis (%) T Thermokinetic temperature (K) T 1 First characteristic temperature, critical temperature (°C) T 2 Second characteristic temperature, active temperature (°C) T 3 Third characteristic temperature, pyrolysis temperature (°C) T 4 Fourth characteristic temperature, ignition temperature (°C) T 5 Fifth characteristic temperature, burned-out temperature (°C)

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Modes and kinetics of CO2 and CO production from low-temperature oxidation of coal

Cited by 101 publications

References 39 publications

Effect of flow rates of gases flowing through a coal bed during coal heating and cooling on concentrations of gases emitted and fire hazard assessment

Effect of flow rates of gases flowing through a coal bed during coal heating and cooling on concentrations of gases emitted and fire hazard assessment

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

Thermal behavior and microcharacterization analysis of second-oxidized coal

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