A DSC study on the impact of low-temperature oxidation on the behavior and drying of water in lignite

  • Salman Khoshk Rish
  • Arash Tahmasebi
  • Jianglong YuEmail author


Low-rank coals may undergo low-temperature oxidation and self-heating during mining, freightage, and handling. The oxidation of coal changes its structure which will be relected in the behaviour of coal water. A differential scanning calorimetry study was conducted to investigate the impact of low-temperature oxidation on the nature of water in a Chinese lignite and its drying behavior. The lignite sample was oxidized in the air at temperatures of 30–180 °C. The results showed that the lignite samples that underwent low-temperature oxidation did not contain any freezable bound water. It was found that the amount of non-freezable water in the oxidized samples reached the highest value of 67.38 mass% after oxidation at 80 °C. The Fourier transform infrared spectroscopy and the static sessile drop analysis results suggested that the concentration of oxygen functionalities and hydrophilicity of lignite samples peaked after oxidation at 80 °C, which in turn increased the tendency for the absorption of water as non-freezable water. It was also found that the types of water in the oxidized samples had a profound impact on its drying behavior, where free water showed higher drying rates compared with freezable bound water and non-freezable water. The coal sample pre-oxidized at 80 °C required higher energy for pre-drying compared with the raw coal, which was attributed to the higher proportion of non-freezable water after oxidation.


Lignite Low-temperature oxidation Freezable water Non-freezable water DSC 



This study was supported by the National Natural Science Foundation of China (21476100 and 21676132).


  1. 1.
    Karthikeyan M, Zhonghua W, Mujumdar AS. Low-rank coal drying technologies—current status and new developments. Dry Technol. 2009;27:403–15.CrossRefGoogle Scholar
  2. 2.
    Jangam SV, Karthikeyan M, Mujumdar AS. A critical assessment of industrial coal drying technologies: role of energy, emissions, risk and sustainability. Dry Technol. 2011;29:395–407.CrossRefGoogle Scholar
  3. 3.
    Allardice DJ, Clemow LM, Favas G, Jackson WR, Marshall M, Sakurovs R. The characterisation of different forms of water in low rank coals and some hydrothermally dried products☆. Fuel. 2003;82:661–7.CrossRefGoogle Scholar
  4. 4.
    Yu J, Tahmasebi A, Han Y, Yin F, Li X. A review on water in low rank coals: the existence, interaction with coal structure and effects on coal utilization. Fuel Process Technol. 2013;106:9–20.CrossRefGoogle Scholar
  5. 5.
    Norinaga K, Kumagai H, Hayashi J-I, Chiba T. Classification of water sorbed in coal on the basis of congelation characteristics. Energy Fuels. 1998;12:574–9.CrossRefGoogle Scholar
  6. 6.
    Tahmasebi A, Yu J, Han Y, Zhao H, Bhattacharya S. A kinetic study of microwave and fluidized-bed drying of a Chinese lignite. Chem Eng Res Des. 2014;92:54–65.CrossRefGoogle Scholar
  7. 7.
    Willson WG, Walsh DAN, Irwinc W. Overview of low-rank coal (LRC) drying. Coal Prep. 1997;18:1–15.CrossRefGoogle Scholar
  8. 8.
    Wang H, Dlugogorski BZ, Kennedy EM. Coal oxidation at low temperatures: oxygen consumption, oxidation products, reaction mechanism and kinetic modelling. Prog Energy Combust Sci. 2003;29:487–513.CrossRefGoogle Scholar
  9. 9.
    Slovák V, Taraba B. Effect of experimental conditions on parameters derived from TG-DSC measurements of low-temperature oxidation of coal. J Therm Anal Calorim. 2010;101:641–6.CrossRefGoogle Scholar
  10. 10.
    Wang K, Deng J, Zhang Y-N, Wang C-P. Kinetics and mechanisms of coal oxidation mass gain phenomenon by TG–FTIR and in situ IR analysis. J Therm Anal Calorim. 2018;132:591–8.CrossRefGoogle Scholar
  11. 11.
    Kus J, Misz-Kennan M. Coal weathering and laboratory (artificial) coal oxidation. Int J Coal Geol. 2017;171:12–36.CrossRefGoogle Scholar
  12. 12.
    Lopez D, Sanada Y, Mondragon F. Effect of low-temperature oxidation of coal on hydrogen-transfer capability. Fuel. 1998;77:1623–8.CrossRefGoogle Scholar
  13. 13.
    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.CrossRefGoogle Scholar
  14. 14.
    Yuan L, Smith AC. CFD modeling of spontaneous heating in a large-scale coal chamber. J Loss Prevent Proc. 2009;22:426–33.CrossRefGoogle Scholar
  15. 15.
    Clemens AH, Matheson TW. The role of moisture in the self-heating of low-rank coals. Fuel. 1996;75:891–5.CrossRefGoogle Scholar
  16. 16.
    Tahmasebi A, Yu J, Han Y, Li X. A study of chemical structure changes of Chinese lignite during fluidized-bed drying in nitrogen and air. Fuel Process Technol. 2012;101:85–93.CrossRefGoogle Scholar
  17. 17.
    Tahmasebi A, Yu J, Bhattacharya S. Chemical structure changes accompanying fluidized-bed drying of Victorian brown coals in superheated steam, nitrogen, and hot air. Energy Fuels. 2013;27:154–66.CrossRefGoogle Scholar
  18. 18.
    Zhao H, Yu J, Liu J, Tahmasebi A. Experimental study on the self-heating characteristics of Indonesian lignite during low temperature oxidation. Fuel. 2015;150:55–63.CrossRefGoogle Scholar
  19. 19.
    Akgün F, Arisoy A. Effect of particle size on the spontaneous heating of a coal stockpile. Combust Flame. 1994;99:137–46.CrossRefGoogle Scholar
  20. 20.
    Wang H, Dlugogorski BZ, Kennedy EM. Analysis of the mechanism of the low-temperature oxidation of coal. Combust Flame. 2003;134:107–17.CrossRefGoogle Scholar
  21. 21.
    Wang H, Dlugogorski BZ, Kennedy EM. Role of inherent water in low-temperature oxidation of coal. Combust Sci Technol. 2003;175:253–70.CrossRefGoogle Scholar
  22. 22.
    Petit JC. A comprehensive study of the water vapour/coal system: application to the role of water in the weathering of coal. Fuel. 1991;70:1053–8.CrossRefGoogle Scholar
  23. 23.
    Lynch LJ, Webster DS. Effect of thermal treatment on the interaction of brown coal and water: a nuclear magnetic resonance study. Fuel. 1982;61:271–5.CrossRefGoogle Scholar
  24. 24.
    Unsworth JF, Fowler CS, Heard NA, Weldon VL, McBrierty VJ. Moisture in coal. Fuel. 1988;67:1111–9.CrossRefGoogle Scholar
  25. 25.
    Tahmasebi A, Yu J, Su H, Han Y, Lucas J, Zheng H, et al. A differential scanning calorimetric (DSC) study on the characteristics and behavior of water in low-rank coals. Fuel. 2014;135:243–52.CrossRefGoogle Scholar
  26. 26.
    Gaisford S, Kett V, Haines P. Principles of thermal analysis and calorimetry. London: Royal Society of Chemistry; 2016.Google Scholar
  27. 27.
    Groenewoud WM. Chapter 1—differential scanning calorimetry. In: Groenewoud WM, editor. Characterisation of polymers by thermal analysis. Amsterdam: Elsevier Science B.V; 2001. p. 10–60.CrossRefGoogle Scholar
  28. 28.
    Höhne G, Hemminger WF, Flammersheim H-J. Differential scanning calorimetry. Berlin: Springer; 2013. p. 31–63.Google Scholar
  29. 29.
    Tahmasebi A, Yu J, Han Y, Yin F, Bhattacharya S, Stokie D. Study of chemical structure changes of Chinese lignite upon drying in superheated steam, microwave, and hot air. Energy Fuels. 2012;26:3651–60.CrossRefGoogle Scholar
  30. 30.
    Meng F, Yu J, Tahmasebi A, Han Y, Zhao H, Lucas J, et al. Characteristics of chars from low-temperature pyrolysis of lignite. Energy Fuels. 2014;28:275–84.CrossRefGoogle Scholar
  31. 31.
    Han Y, Liao J, Bai Z, Chaffee AL, Chang L, Li W. Study on the relationship between pore structure and water forms in pore using partially gasified lignite char. Energy Fuels. 2016;30:8875–85.CrossRefGoogle Scholar
  32. 32.
    Ferrasse J-H, Lecomte D. Simultaneous heat-flow differential calorimetry and thermogravimetry for fast determination of sorption isotherms and heat of sorption in environmental or food engineering. Chem Eng Sci. 2004;59:1365–76.CrossRefGoogle Scholar
  33. 33.
    Nwaka D, Tahmasebi A, Tian L, Yu J. The effects of pore structure on the behavior of water in lignite coal and activated carbon. J Colloid Interface Sci. 2016;477:138–47.CrossRefGoogle Scholar
  34. 34.
    Hayashi J-I, Norinaga K, Kudo N, Chiba T. Estimation of size and shape of pores in moist coal utilizing sorbed water as a molecular probe. Energy Fuels. 2001;15:903–9.CrossRefGoogle Scholar
  35. 35.
    Wang D, Zhong X, Gu J, Qi X. Changes in active functional groups during low-temperature oxidation of coal. Min Sci Technol (China). 2010;20:35–40.CrossRefGoogle Scholar
  36. 36.
    Tekely P, Nicole D, Delpuech JJ, Totino E, Muller JF. Chemical structure changes in coals after low-temperature oxidation and demineralization by acid treatment as revealed by high resolution solid state 13C NMR. Fuel Process Technol. 1987;15:225–31.CrossRefGoogle Scholar
  37. 37.
    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. 2018;131:2963–74.CrossRefGoogle Scholar
  38. 38.
    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.CrossRefGoogle Scholar
  39. 39.
    Förch R, Schönherr H, Jenkins ATA. Surface design: applications in bioscience and nanotechnology. New York: Wiley; 2009.CrossRefGoogle Scholar
  40. 40.
    Xia W, Xie G. Changes in the hydrophobicity of anthracite coals before and after high temperature heating process. Powder Technol. 2014;264:31–5.CrossRefGoogle Scholar
  41. 41.
    Xia W, Yang J. Changes in surface properties of anthracite coal before and after inside/outside weathering processes. Appl Surf Sci. 2014;313:320–4.CrossRefGoogle Scholar
  42. 42.
    Xia W. The effect of heating on the wettability of lignite. Energy Sour A. 2016;38:3521–6.CrossRefGoogle Scholar
  43. 43.
    Zhou G, Xu C, Cheng W, Zhang Q, Nie W. Effects of oxygen element and oxygen-containing functional groups on surface wettability of coal dust with various metamorphic degrees based on XPS experiment. J Anal Methods Chem. 2015;2015:8.Google Scholar
  44. 44.
    Vorres KS. Effect of temperature, sample size, and gas flow rate on drying on Beulah-Zap lignite and Wyodak subbituminous coal. Energy Fuels. 1994;8:320–3.CrossRefGoogle Scholar
  45. 45.
    Wang R, Liu J, Hu Y, Zhou J, Cen K. Ultrasonic sludge disintegration for improving the co-slurrying properties of municipal waste sludge and coal. Fuel Process Technol. 2014;125:94–105.CrossRefGoogle Scholar
  46. 46.
    Weigl K, Schuster G, Stamatelopoulos GN, Friedl A. Increasing power plant efficiency by fuel drying. Comput Chem Eng. 1999;23:S919–22.CrossRefGoogle Scholar

Copyright information

© Akadémiai Kiadó, Budapest, Hungary 2019

Authors and Affiliations

  1. 1.Key Laboratory of Advanced Coal and Coking Technology of Liaoning Province, School of Chemical EngineeringUniversity of Science and Technology LiaoningAnshanChina
  2. 2.Chemical EngineeringUniversity of NewcastleCallaghanAustralia

Personalised recommendations