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Gases and thermal behavior during high-temperature oxidation of weathered coal

  • Jun Deng
  • Jia-Jia Song
  • Jing-Yu ZhaoEmail author
  • Yan-Ni Zhang
  • Yu-Xuan Zhang
  • Chi-Min ShuEmail author
Article
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Abstract

In order to investigate the spontaneous combustion characteristics of weathered coal, gas generation and thermal behavior of weathered and fresh coal were analyzed. A self-made high-temperature-programmed experimental system was applied to simulate the spontaneous combustion of weathered and fresh coal. The characteristic parameters during oxidation were between 30 and 650 °C. The growth rate obtained through the analysis of an indicator gas was adopted to calculate the characteristic temperatures of high-temperature spontaneous combustion of coal. A C80 Calvet calorimeter was used to capture the thermal behavior during oxidation. At a high temperature and low oxygen concentration, weathered coal continued oxidizing and releasing thermal energy to sustain oxidation. The concentration of gases produced through high-temperature oxidation was lower for weathered coal than for fresh coal. The exothermic onset temperature of weathered coal was 43 °C, which was lower than the exothermic onset temperature of fresh coal. A salient difference was observed in the thermal energy release between weathered coal and fresh coal at different oxidation stages. From the critical temperature to crack temperature, the percentage of thermal energy release of weathered coal was much lower than that of fresh coal.

Keywords

Spontaneous combustion Characteristic temperature Exothermic onset temperature Thermal energy release Oxidation stage 

List of symbols

Aad

Ash content on an air-dried basis (%)

FCad

Fixed carbon on an air-dried basis (%)

Mad

Moisture on an air-dried basis (%)

T1

First characteristic temperature, critical temperature (°C)

T2

Second characteristic temperature, active temperature (°C)

T3

Third characteristic temperature, pyrolysis temperature (°C)

T4

Fourth characteristic temperature, ignition temperature (°C)

T5

Fifth characteristic temperature, burned-out temperature (°C)

Vad

Volatile content on an air-dried basis (%)

Notes

Acknowledgements

This manuscript was edited by Wallace Academic Editing. This Project was supported by National Natural Science Foundation of China (Grant No. 5167-4191), National Natural Science Foundation of China of China (Grant No. 5180-4246), and Natural Science Basic Research Plan in Shaanxi Province of China (Program No. 2017JQ5047).

References

  1. 1.
    Saini V, Gupta RP, Arora MK. Environmental impact studies in coalfields in India: a case study from Jharia coal-field. Renew Sustain Energy Rev. 2016;53:1222–39.Google Scholar
  2. 2.
    Lei CK, Deng J, Cao K, Ma L, Xiao Y, Ren LF. A random forest approach for predicting coal spontaneous combustion. Fuel. 2018;223:63–73.Google Scholar
  3. 3.
    Petit JC. Calorimetric evidence for a dual mechanism in the low temperature oxidation of coal. J Therm Anal Calorim. 1991;37(8):1719–26.Google Scholar
  4. 4.
    Ma SP, Hill JO, Heng S. A thermal analysis study of the oxidation of brown coal chars. J Therm Anal Calorim. 1989;35(5):1611–9.Google Scholar
  5. 5.
    Deng J, Xiao Y, Li QW, Lu JH, Wen H. Experimental studies of spontaneous combustion and anaerobic cooling of coal. Fuel. 2015;157:261–9.Google Scholar
  6. 6.
    Deng J, Zhao JY, Xiao Y, Zhang YN, Huang AC, Shu CM. Thermal analysis of the pyrolysis and oxidation behaviour of 1/3 coking coal. J Therm Anal Calorim. 2017;129(3):1–8.Google Scholar
  7. 7.
    Xiao Y, Ren SJ, Deng J, Shu CM. Comparative analysis of thermokinetic behavior and gaseous products between first and second coal spontaneous combustion. Fuel. 2018;227:325–33.Google Scholar
  8. 8.
    Guo BC, Wang NB, Qi T, Lai XP. Detection and determination of seam releasing zone in slope of Zhundong surface mine. Coal Sci Technol. 2010;38(3):5–7.Google Scholar
  9. 9.
    Cox JL. Concern over coal samples. Fuel. 1984;63:1030–1.Google Scholar
  10. 10.
    Zhang RX, Xie HP, Xie ZK. Experimental study on spontaneous combustion of ground coal. J China Univ Min Technol. 2000;29(3):235–8.Google Scholar
  11. 11.
    Marchioni DL. The detection of weathering in coal by petrographic, rheologic and chemical methods. Int J Coal Geol. 1983;2:231–59.Google Scholar
  12. 12.
    Davis RC, Noon SW, Harrington J. The petroleum potential of tertiary coal from Western Indonesia: relationship to mire type and sequence stratigraphic setting. Int J Coal Geol. 2007;70:35–52.Google Scholar
  13. 13.
    Kruszewska KJ, Du Cann VM. Detection of the incipient oxidation of coal by petrographic techniques. Fuel. 1996;75:769–74.Google Scholar
  14. 14.
    Misz M, Fabiańska M, Ćmiel S. Organic components in thermally altered coal waste: preliminary petrographic and geochemical investigations. Int J Coal Geol. 2007;71:405–24.Google Scholar
  15. 15.
    Wagner NJ. The abnormal condition analysis used to characterize weathered discard coals. Int J Coal Geol. 2007;72:177–86.Google Scholar
  16. 16.
    Jolanta K, Uwe M, Jianwei M. Oxidation and carbonization of coals: a case study of coal fire affects coals from the Wuda coalfield, Inner Mongolia, China. Gen Assem Eur Geosci Union. 2010;12:EGU2010–EG11851.Google Scholar
  17. 17.
    Magdalena M, Monika F. Thermal transformation of organic matter in coal waste from Rymer Cones (Upper Silesian Coal Basin, Poland). Int J Coal Geol. 2010;81:343–58.Google Scholar
  18. 18.
    Wang ZB, Wang C, Kang RN, Bin F, Wei XL. Deoxygenation of Chinese long-flame coal in low-temperature pyrolysis. J Therm Anal Calorim. 2017;3:1–9.Google Scholar
  19. 19.
    Rotaru A, Nicolaescu I, Rotaru P, Neaga C. Thermal characterization of humic acids and other components of raw coal. J Therm Anal Calorim. 2008;92(1):297–300.Google Scholar
  20. 20.
    Cui X, Li XL, Li YM, Li S. Evolution mechanism of oxygen functional groups during pyrolysis of Datong coal. J Therm Anal Calorim. 2017;1:1–12.Google Scholar
  21. 21.
    Jin YF, Guo J, Wen H, Liu WY, Wang K, Ma XF. Experimental study on the high temperature lean oxygen oxidation combustion characteristic parameters of coal spontaneous combustion. J China Coal Soc. 2015;40(3):596–602.Google Scholar
  22. 22.
    Kus J. Impact of underground coal fire on coal petrographic properties of high volatile bituminous coals: a case study from coal fire zone No. 3.2 in the Wuda coalfield, inner Mongolia autonomous region North China. Int J Coal Geol. 2017;171:185–211.Google Scholar
  23. 23.
    Kus J. Oxidatively and thermally altered high-volatile bituminous coals in high-temperature coal fire zone No. 8 of the Wuda coalfield (North China). Int J Coal Geol. 2017;176:8–35.Google Scholar
  24. 24.
    Zhang YL, Wang JF, Wu JM, Chang LP. Modes and kinetics of CO2 and CO production from low-temperature oxidation of coal. Int J Coal Geol. 2015;140:1–8.Google Scholar
  25. 25.
    Deng J, Zhao JY, Zhang YN, Geng RL. Study on coal spontaneous combustion characteristic temperature of growth rate analysis. Procedia Eng. 2014;84:796–805.Google Scholar
  26. 26.
    Válková D, Kislinger J, Pekař M, Kučerík J. The kinetics of thermo-oxidative humic acids degradation studied by isoconversional methods. J Therm Anal Calorim. 2007;89(3):957–64.Google Scholar
  27. 27.
    Nagar BR, Waight ES, Meuzelaar HLC, Kistemaker PG. Studies on the structure and origin of soil humic acids by curie point pyrolysis in direct combination with low-voltage mass spectrometry. Plant Soil. 1975;43:681–5.Google Scholar
  28. 28.
    Saleh M, Nugroho YS. Thermogravimetric study of the effect of particle size on the spontaneous combustion of Indonesian low rank coal. Appl Mech Mater. 2013;330(330):101–5.Google Scholar
  29. 29.
    Küçük A, Kadıoğlu Y, Gülaboğlu MŞ. A study of spontaneous combustion characteristics of a Turkish lignite: particle size, moisture of coal, humidity of air. Combust Flame. 2003;133(3):255–61.Google Scholar
  30. 30.
    Qin YP, Song YM, Yang XB, Qin C. Experimental study on coal granularity influencing oxidation rate in goaf. J China Coal Soc. 2010;35:132–5.Google Scholar

Copyright information

© Akadémiai Kiadó, Budapest, Hungary 2019

Authors and Affiliations

  1. 1.School of Safety Science and EngineeringXi’an University of Science and TechnologyXi’anPeople’s Republic of China
  2. 2.Shaanxi Key Laboratory of Prevention and Control of Coal FireXi’an University of Science and TechnologyXi’anPeople’s Republic of China
  3. 3.Department of Safety, Health, and Environmental EngineeringNational Yunlin University of Science and Technology (YunTech)YunlinROC
  4. 4.Center for Process Safety and Industrial Disaster Prevention, School of EngineeringYunTechYunlinROC

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