A TGA–DSC-based study on macroscopic behaviors of coal–oxygen reactions in context of underground coal fires

Abstract

Underground coal fires (UCFs) cause remarkable loss of energy resources and significant environmental pollution. Due to the limited capacity of oxygen transport, the inception and development of UCFs represent a very unique mode of coal–oxygen reactions. Therefore, a high-volatile flammable coal sample is thermally analyzed with the combined TGA–DSC approach under four oxygen concentrations (21%, 15%, 9% and 3%) and three heating rates (1 °C min−1, 2 °C min−1 and 5 °C min−1). It is found that the oxygen concentration does not significantly influence the early (low-temperature) stage of coal–oxygen reactions. With the decrease in oxygen concentration, the intensity of the exothermic reactions is reduced and the duration of reactions is extended. Based on the experimental results, the apparent activation energy is calculated. The variation of the apparent activation energy reflects the different reaction stages: volatiles burning and char oxidation, which is verified by the TGA–DSC results. Under the extreme condition of 3% oxygen concentration, a very distinct macroscopic thermochemical behavior is observed, and the limited oxygen supply controls the reaction rate throughout the entire process, which qualitatively explains the persistency of the burning phenomena in most UCFs.

This is a preview of subscription content, access via your institution.

Fig. 1

(adapted from Ref. [26] with TC denoting thermocouple)

Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7

References

  1. 1.

    Kuenzer C, Zhang J, Tetzlaff A, van Dijk P, Voigt S, Mehl H, et al. Uncontrolled coal fires and their environmental impacts: Investigating two arid mining regions in north-central China. Appl Geogr. 2007;27:42–62.

    Article  Google Scholar 

  2. 2.

    Stracher GB, Taylor TP. Coal fires burning out of control around the world: thermodynamic recipe for environmental catastrophe. Int J Coal Geol. 2004;59:7–17.

    CAS  Article  Google Scholar 

  3. 3.

    Melody SM, Johnston FH. Coal mine fires and human health: What do we know? Int J Coal Geol. 2015;152:1–14.

    CAS  Article  Google Scholar 

  4. 4.

    Zhang Y, Li Y, Huang Y, Li S, Wang W. Characteristics of mass, heat and gaseous products during coal spontaneous combustion using TG/DSC–FTIR technology. J Therm Anal Calorim. 2017;131:2963–74.

    Article  Google Scholar 

  5. 5.

    Tang Y, Wang H. Experimental investigation on microstructure evolution and spontaneous combustion properties of secondary oxidation of lignite. Process Saf Environ. 2019;124:143–50.

    CAS  Article  Google Scholar 

  6. 6.

    Carras JN, Young BC. Self-heating of coal and related materials: models, application and test methods. Prog Energ Combust. 1994;20:1–15.

    Article  Google Scholar 

  7. 7.

    Wang H, Dlugogorski BZ, Kennedy EM. Coal oxidation at low temperatures: oxygen consumption, oxidation products, reaction mechanism and kinetic modelling. Prog Energ Combust. 2003;29:487–513.

    CAS  Article  Google Scholar 

  8. 8.

    Green U, Aizenshtat Z, Metzger L, Cohen H. Field and Laboratory Simulation Study of Hot Spots in Stockpiled Bituminous Coal. Energ Fuel. 2012;26:7230–5.

    CAS  Article  Google Scholar 

  9. 9.

    Zhang Y, Wu J, Chang L, Wang J, Xue S. Kinetic and thermodynamic studies on the mechanism of low-temperature oxidation of coal: A case study of Shendong coal (China). Int J Coal Geol. 2013;120:41–9.

    CAS  Article  Google Scholar 

  10. 10.

    Wang H, Dlugogorski BZ, Kennedy EM. Examination of CO2, CO, and H2O Formation during low-temperature oxidation of a Bituminous Coal. Energ Fuel. 2002;16:586–92.

    CAS  Article  Google Scholar 

  11. 11.

    Dong X, Wen Z, Wang F, Meng Y. Law of gas production during coal heating oxidation. Int J Min Sci Techno. 2019;29:617–20.

    CAS  Article  Google Scholar 

  12. 12.

    Yang Y, Li Z, Hou S, Gu F, Gao S, Tang Y. The shortest period of coal spontaneous combustion on the basis of oxidative heat release intensity. Int J Min Sci Techno. 2014;24:99–103.

    CAS  Article  Google Scholar 

  13. 13.

    Jayaraman K, Gökalp I. Thermal characterization, gasification and kinetic studies of different sized Indian coal and char particles. Int J Eng Sci. 2014;6:31–40.

    Google Scholar 

  14. 14.

    Song Z, Huang X, Luo M, Gong J, Pan X. Experimental study on the diffusion–kinetics interaction in heterogeneous reaction of coal. J Therm Anal Calorim. 2017;129:1625–37.

    CAS  Article  Google Scholar 

  15. 15.

    Wang D, Xin H, Qi X, Dou G, Qi G, Ma L. Reaction pathway of coal oxidation at low temperatures: a model of cyclic chain reactions and kinetic characteristics. Combust Flame. 2016;163:447–60.

    CAS  Article  Google Scholar 

  16. 16.

    Arisoy A, Beamish B. Reaction kinetics of coal oxidation at low temperatures. Fuel. 2015;159:412–7.

    CAS  Article  Google Scholar 

  17. 17.

    Kim CJ, Sohn CH. A novel method to suppress spontaneous ignition of coal stockpiles in a coal storage yard. Fuel Process Technol. 2012;100:73–83.

    CAS  Article  Google Scholar 

  18. 18.

    Rosema A, Guan H, Veld H. Simulation of spontaneous combustion, to study the causes of coal fires in the Rujigou Basin. Fuel. 2001;80:7–16.

    CAS  Article  Google Scholar 

  19. 19.

    Song Z, Wu D, Jiang J, Pan X. Thermo-solutal buoyancy driven air flow through thermally decomposed thin porous media in a U-shaped channel: Towards understanding persistent underground coal fires. Appl Therm Eng. 2019;159:113948.

    CAS  Article  Google Scholar 

  20. 20.

    Song Z, Huang X, Jiang J, Pan X. A laboratory approach to CO2 and CO emission factors from underground coal fires. Int J Coal Geol. 2020;219:103382.

    CAS  Article  Google Scholar 

  21. 21.

    Yang J, Liu N, Chen H, Gao W, Tu R. Effects of atmospheric oxygen on horizontal peat smoldering fires: Experimental and numerical study. Proc Combust Inst. 2018;37:4063–71.

    Article  Google Scholar 

  22. 22.

    Qi G, Wang D, Zheng K, Tang Y, Lu X. Smoldering combustion of coal under forced air flow: experimental investigation. J Fire Sci. 2016;34:267–88.

    CAS  Article  Google Scholar 

  23. 23.

    Song Z, Kuenzer C. Coal fires in China over the last decade: A comprehensive review. Int J Coal Geol. 2014;133:72–99.

    CAS  Article  Google Scholar 

  24. 24.

    Kök M. Recent developments in the application of thermal analysis techniques in fossil fuels. J Therm Anal Calorim. 2008;91:763–73.

    Article  Google Scholar 

  25. 25.

    Russell N, Beeley T, Man CK, Gibbins J, Williamson J. Development of TG measurements of intrinsic char combustion reactivity for industrial and research purposes. Fuel Process Technol. 1998;57:113–30.

    CAS  Article  Google Scholar 

  26. 26.

    Li J, Fu P, Mao Y, Saini V, Sokol E. A Parametric Study on the Inception and Evolution of Underground Coal Fires Based on a Lab-Scale Experimental Setup. Fire Technol. 2019;56:1039–57.

    Article  Google Scholar 

  27. 27.

    Qi X, Li Q, Zhang H, Xin H. Thermodynamic characteristics of coal reaction under low oxygen concentration conditions. J Energy Inst. 2017;90:544–55.

    CAS  Article  Google Scholar 

  28. 28.

    Li Z, Zhang Y, Jing X, Zhang Y, Chang L. Insight into the intrinsic reaction of brown coal oxidation at low temperature: Differential scanning calorimetry study. Fuel Process Technol. 2016;147:64–70.

    CAS  Article  Google Scholar 

  29. 29.

    Deng J, Li Q, Xiao Y, Wen H. The effect of oxygen concentration on the non-isothermal combustion of coal. Thermochim Acta. 2017;653:106–15.

    CAS  Article  Google Scholar 

  30. 30.

    Qi G, Wang D, Zheng K, Xu J, Qi X, Zhong X. Kinetics characteristics of coal low-temperature oxidation in oxygen-depleted air. J Loss Prevent Proc. 2015;35:224–31.

    CAS  Article  Google Scholar 

  31. 31.

    Li Q, Xiao Y, Wang C, Deng J, Shu C. Thermokinetic characteristics of coal spontaneous combustion based on thermogravimetric analysis. Fuel. 2019;250:235–44.

    CAS  Article  Google Scholar 

  32. 32.

    Naktiyok J. Determination of the self-heating temperature of coal by means of TGA analysis. Energ Fuel. 2018;32:2299–305.

    CAS  Article  Google Scholar 

  33. 33.

    Li X, Li C, Zhang H, Li W. Analysis on the status and problems of lignite application in China. Appl Chem Ind. 2020;49:1226–30 ([in Chinese]).

    Google Scholar 

  34. 34.

    Xin H, Wang H, Kang W, Di C, Qi X, Zhong X, et al. The reburning thermal characteristics of residual structure of lignite pyrolysis. Fuel. 2020;259:116226.

    CAS  Article  Google Scholar 

  35. 35.

    Wang C, Zhang X, Liu Y, Che D. Pyrolysis and combustion characteristics of coals in oxy-fuel combustion. Appl Energ. 2012;97:264–73.

    CAS  Article  Google Scholar 

  36. 36.

    Liu Y, Cao X, Duan X, Wang Y, Che D. Thermal analysis on combustion characteristics of predried dyeing sludge. Appl Therm Eng. 2018;140:158–65.

    CAS  Article  Google Scholar 

  37. 37.

    Vyazovkin S, Burnham AK, Criado JM, Pérez-Maqueda LA, Popescu C, Sbirrazzuoli N. ICTAC Kinetics Committee recommendations for performing kinetic computations on thermal analysis data. Thermochim Acta. 2011;520:1–1.

    CAS  Article  Google Scholar 

Download references

Acknowledgements

The authors gratefully acknowledge the financial support provided by the National Natural Science Foundation of China (Grant No. 51850410504) and Open Projects of State Key Laboratory of Coal Resources and Safe Mining of CUMT (Grant No. 14KF01).

Author information

Affiliations

Authors

Corresponding author

Correspondence to Jun Li.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Li, J., Yang, Y., Li, J. et al. A TGA–DSC-based study on macroscopic behaviors of coal–oxygen reactions in context of underground coal fires. J Therm Anal Calorim (2021). https://doi.org/10.1007/s10973-021-10671-z

Download citation

Keywords

  • Underground coal fires
  • Coal–oxygen reactions
  • Oxygen concentration
  • Heating rate
  • TGA–DSC
  • Apparent activation energy