Coal spontaneous combustion is an extremely complicated physical and chemical changing process. In order to improve the indicator gases detection technology and coal spontaneous combustion monitoring, a novel forecast method for toxic gases emission from coal oxidation at low temperature is presented in this paper. The experiment system is setup combined with frequency-domain terahertz technology and coal temperature programming device. The concentration curves of carbon monoxide and sulphur dioxide gases from coal spontaneous combustion are estimated according to molecule terahertz spectra. The influences of coal rank and oxygen supply on coal spontaneous combustion characteristics are discussed. Both carbon monoxide and sulphur dioxide gases absorption spectra show the characteristic equi-spaced absorption peaks. Results demonstrate that under the condition of lean oxygen, there exists a critical oxygen concentration in the process of coal oxidation at low temperature. Comparing with Fourier infrared spectrum testing, the presented method is highly accurate and more sensitive, especially suitable for early-stage monitoring of the indicator gases produced by coal spontaneous combustion.
If the inline PDF is not rendering correctly, you can download the PDF file here.
 Pone JDN Hein KAA Stracher GB Annegarn HJ Finkelman RB Blake DR et al. The spontaneous combustion of coal and its by-products in the Witbank and Sasolburg coaldfields of South Africa. Int J Coal Geol. 2007;72:124-140. DOI: 10.1016/j.coal.2007.01.001.
 Misz M Fabiańska M Ćmiel S. Organic components in thermally altered coal waste: preliminary petrographic and geochemical investigations. Int J Coal Geol. 2007;71:405-424. DOI: 10.1016/j.coal.2006.08.009.
 Misz M Fabiańska M. Thermal transformation of organic matter in coal waste from Rymer Cones (Upper Silesian Coal Basin Poland). Int J Coal Geol. 2010;81(4):343-358. DOI: 10.1016/j.coal.2009.08.009.
 Finkelman RB. Potential health impacts of burning coal beds and waste banks. Int J Coal Geol. 2004;51:19-24. DOI: 10.1016/j.coal.2003.11.002.
 Simoneit BRD Bi X Orors DR Medeiros PM Sheng G Fu J. Phenols and hydroxy-PAHs (arylphenols) as tracer for coal smoke particulate matter: source tests and ambient aerosol assessment. Environ Sci Technol. 2007;41:7294-7302. DOI: 10.1021/es071072u.
 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. DOI:10.1016/j.coal.2003.03.002.
 Stracher GB Hower JC Schroeder PA Fleisher C Kitson J Barwick LH et al. Environmental dangers of coal fires in Kentucky and Alabama. Geological Society of America Abstracts with Program 2008;310-7.
 Hower JC Henke K O'Keefe JMK Engle MA Blake DR Stracher GB. The Tiptop coal mine fire Kentucky: preliminary investigation of the measurement of mercury carbon dioxide and carbon monoxide from coal-fire gas vents. Int J Coal Geol. 2009;80: 63-67. DOI: 10.1016/j.coal.2009.08.005.
 Hower JC Rangwala AS O'Keefe JMK Henke K Engle MA. Time series analysis of CO emissions from a coal fire Eastern Kentucky. Geochim Cosmochim Acta. 2010;74:A422.
 Ribeiro J Ferreira da Silva E Flores D. Burning of coal waste piles from Douro Coalfield (Portugal): petrological geochemical and mineralogical characterization. Int J Coal Geol. 2009;81(4):359-372. DOI: 10.1016/j.coal.2009.10.005.
 Zhao Y Zhang J Chou CL Li Y Wang Z Ge Y et al. Trace element emissions from spontaneous combustion of gob piles in coal mines Shanxi China. Int J Coal Geol. 2008;73:52-62. DOI: 10.1016/j.coal.2007.07.007.
 O'Keefe JMK Henke K Hower JC Engle MA Stracher GB Stucker JD et al. CO CO2 and Hg emission rates from the Truman Shepherd and Ruth Mullins coal fires Eastern Kentucky. Sci Total Environ. 2010;408:1628-1633. DOI: 10.1016/j.scitotenv.2009.12.005.
 Matsushima N Kazahaya K Saito G Shinohara H. Mass and heat flux of volcanic gas discharging from the summit crater of Iwodake volcano Satsuma-Iwojima Japan during 1996-1999. J Volcanol Geotherm Res. 2003;126:285-301. DOI: 10.1016/S0377-0273(03)00152-5.
 Exter van M Fattinger C Grischkowsky D. Terahertz time-domain spectroscopy of water vapor. Opt Lett. 1989;14:1128-1130. DOI: 10.1364/OL.14.001128.
 Harde H Zhao J. THz time-domain spectroscopy on ammonia. J Phys Chem A. 2001;105:6038-6047. DOI: 10.1021/jp0101099
 Matron S Rohart F Bocquetr R. Terahertz spectroscopy applied to the measurement of strengths and serf-broadening coefficients for high-J lines of OCS. J Mol Spectrosc. 2006;239:182-189. DOI: 10.1016/j.jms.2006.07.004.
 Hu Y Wang XH Guo LT Zhang CL. Terahertz time domain spectroscopic study of carbon monoxide.Spectrosc Spect Anal. 2006;26(6):1008-1011.
 Almoayed NN Piyade BC Afsar MN. High-resolution absorption coefficient and refractive index spectra of common pollutant gases at millimeter and THz wavelengths. Proc SPIE 2007;6772: 67720G. DOI: 10.1117/12.737143.