Mechanical Performances and Pore Features of Coal Subjected to Heat Treatment in Approximately Vacuum Environment
Publication: International Journal of Geomechanics
Volume 20, Issue 7
Abstract
The physical and mechanical performances of coal, which does not just depend on the initial mineral composition and structure, are also dominated by the later engineering and geology environments, including high temperature, water saturation, and corrosive effect. In this paper, coal specimens, after high temperature treatment in an approximately vacuum environment, were conducted to the uniaxial compression, Brazilian split, scanning electron microscope (SEM) and mercury intrusion tests, respectively, to investigate the influence of temperature on the mechanical behaviors and pore features. The results showed that the mechanical parameters decrease gradually with an increase in temperature, presenting four stages: 25°C–200°C, 200°C–300°C, 300°C–400°C, and greater than 400°C. Increases in temperature also lead to the increase of porosity, together with the transformation of pore diameter, especially at 400°C–450°C because of the seriously thermal cracking and decomposition. Unexpectedly, due to the structure redistribution of mineral grains, from 450°C to 500°C, both the porosity and pore diameter show a drastic drop.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
This study is supported by the Fundamental Research Funds for the Central Universities of China (No. 2018XKQYMS07).
References
Abdulagatov, I. M., Z. Z. Abdulagatova, S. N. Kallaev, A. G. Bakmaev, and P. G. Ranjith. 2015. “Thermal-diffusivity and heat-capacity measurements of sandstone at high temperatures using laser flash and DSC methods.” Int. J. Thermophys. 36 (4): 658–691. https://doi.org/10.1007/s10765-014-1829-4.
Bauer, S., and A. Urquhart. 2016. “Thermal and physical properties of reconsolidated crushed rock salt as a function of porosity and temperature.” Acta Geotech. 11 (4): 913–924. https://doi.org/10.1007/s11440-015-0414-8.
Chaki, S., M. Takarli, and W. P. Agbodjan. 2008. “Influence of thermal damage on physical properties of a granite rock: Porosity, permeability and ultrasonic wave evolutions.” Constr. Build. Mater. 22 (7): 1456–1461. https://doi.org/10.1016/j.conbuildmat.2007.04.002.
Ferrero, A. M., and P. Marini. 2001. “Experimental studies on the mechanical behaviour of two thermal cracked marbles.” Rock Mech. Rock Eng. 34 (1): 57–66. https://doi.org/10.1007/s006030170026.
Hu, J. J., Q. Sun, S. E. Chen, and W. Q. Zhang. 2018. “The thermodynamic properties variation of cemented clay after treatment at high temperatures.” Constr. Build. Mater. 182: 523–529. https://doi.org/10.1016/j.conbuildmat.2018.06.137.
Kumari, W. G. P., P. G. Ranjith, M. B. A. Perera, B. K. Chen, and I. M. Abdulagatov. 2017. “Temperature-dependent mechanical behaviour of Australian Strathbogie granite with different cooling treatments.” Eng. Geol. 229: 31–44. https://doi.org/10.1016/j.enggeo.2017.09.012.
Mahanta, B., T. N. Singh, and P. G. Ranjith. 2016. “Influence of thermal treatment on mode I fracture toughness of certain Indian rocks.” Eng. Geol. 210: 103–114. https://doi.org/10.1016/j.enggeo.2016.06.008.
Niu, S. W., Y. S. Zhao, and Y. Q. Hu. 2014. “Experimental investigation of the temperature and pore pressure effect on permeability of lignite under the in situ condition.” Transp. Porous Media 101: 137–148. https://doi.org/10.1007/s11242-013-0236-9.
Peng, S. J., Y. M. Ding, W. D. Lu, and H. Guo. 2016. “Experiment study on effect of temperature on mechanical properties of two types of coal containing gas.” Mine Eng. 4 (1): 30–35. https://doi.org/10.12677/ME.2016.41006.
Perera, M. S. A., P. G. Ranjith, S. K. Choi, and D. Airey. 2012. “Investigation of temperature effect on permeability of naturally fractured black coal for carbon dioxide movement: An experimental and numerical study.” Fuel 94: 596–605. https://doi.org/10.1016/j.fuel.2011.10.026.
Ranjith, P. G., D. R. Viete, B. J. Chen, and M. S. A. Perera. 2012. “Transformation plasticity and the effect of temperature on the mechanical behaviour of Hawkesbury sandstone at atmospheric pressure.” Eng. Geol. 151: 120–127. https://doi.org/10.1016/j.enggeo.2012.09.007.
Rossi, E., M. A. Kant, C. Madonna, M. O. Saar, and P. R. von Rohr. 2018. “The effects of high heating rate and high temperature on the rock strength: Feasibility study of a thermally assisted drilling method.” Rock Mech. Rock Eng. 51 (9): 2957–2964. https://doi.org/10.1007/s00603-018-1507-0.
Shao, S., P. G. Ranjith, P. L. P. Wasantha, and B. K. Chen. 2015. “Experimental and numerical studies on the mechanical behaviour of Australian Strathbogie granite at high temperatures: An application to geothermal energy.” Geothermics 54: 96–108. https://doi.org/10.1016/j.geothermics.2014.11.005.
Wan, Z. J., Z. J. Feng, Y. S. Zhao, Y. Zhang, G. W. Li, and C. B. Zhou. 2011. “Elastic modulus’s evolution law of coal under high temperature and triaxial stress.” [In Chinese.] J. China Coal Soc. 36 (10): 1736–1740.
Xie, H. P. 1989. “The fractal effect of irregularity of crack branching on the fracture toughness of brittle materials.” Int. J. Fract. 41 (4): 267–274. https://doi.org/10.1007/BF00018858.
Xie, H. P., F. Gao, H. W. Zhou, and J. P. Zuo. 2003. “Fractal fracture and fragmentation in rocks.” [In Chinese.] J. Disaster Prev. Mitigation Eng. 23 (4): 1–9.
Xu, J., D. D. Zhang, S. J. Peng, D. Liu, and L. Wang. 2011. “Experimental research on influence of temperature on mechanical properties of coal containing methane.” [In Chinese.] Chin. J. Rock Mech. Eng. 30 (Suppl. 1): 2730–2735.
Yang, S. Q., W. L. Tian, and Y. H. Huang. 2018. “Failure mechanical behavior of pre-holed granite specimens after elevated temperature treatment by particle flow code.” Geothermics 72: 124–137. https://doi.org/10.1016/j.geothermics.2017.10.018.
Yin, G. Z., C. B. Jiang, J. G. Wang, and J. Xu. 2013. “Combined effect of stress, pore pressure and temperature on methane permeability in anthracite coal: An experimental study.” Transp. Porous Media 100: 1–16. https://doi.org/10.1007/s11242-013-0202-6.
Yin, T. B., X. B. Li, W. Z. Cao, and K. W. Xia. 2015. “Effects of thermal treatment on tensile strength of Laurentian granite using Brazilian test.” Rock Mech. Rock Eng. 48 (6): 2213–2223. https://doi.org/10.1007/s00603-015-0712-3.
Yin, T. B., P. Wang, X. B. Li, B. B. Wu, M. Tao, and R. H. Shu. 2016. “Determination of dynamic flexural tensile strength of thermally treated Laurentian granite using semi-circular specimens.” Rock Mech. Rock Eng. 49 (10): 3887–3898. https://doi.org/10.1007/s00603-016-0920-5.
Zhang, Y. L., Q. Sun, L. W. Cao, and J. S. Geng. 2017. “Pore, mechanics and acoustic emission characteristics of limestone under the influence of temperature.” Appl. Therm. Eng. 123: 1237–1244. https://doi.org/10.1016/j.applthermaleng.2017.05.199.
Information & Authors
Information
Published In
International Journal of Geomechanics
Volume 20 • Issue 7 • July 2020
Copyright
© 2020 American Society of Civil Engineers.
History
Received: Apr 8, 2019
Accepted: Dec 19, 2019
Published online: Apr 20, 2020
Published in print: Jul 1, 2020
Discussion open until: Sep 21, 2020
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.