Journal of Thermal Analysis and Calorimetry

, Volume 96, Issue 3, pp 741–749 | Cite as

Fire and explosion properties examinations of toluene–methanol mixtures approached to the minimum oxygen concentration



The minimum oxygen concentration (MOC) is an important safety parameter of safety for fire/explosion prevention of practical processes with fuel-air-inert mixtures. In this study, the critical fire and explosion properties stand for the explosion sensitivity (lower explosion limit (LEL), upper explosion limit (UEL)), explosion maximum indices (maximum explosion pressure (Pmax), maximum rate of explosion pressure rise (dP dt−1)max) and explosion damage degree (gas or vapor deflagration index (Kg)/St Class). These imperative parameters of various toluene/methanol mixing solvents (100/0, 75/25, 50/50, 25/75 and 0/100 vol.%) were experimentally determined within a closed spherical vessel of 20 L (20-L-Apparatus) at 101 kPa and 150 °C. Particularly, we discussed the variations both on the above characteristics and implied flammability hazard degree within different initial oxygen circumstances; the specific effects on toluene/methanol mixing solvents were to be clarified accompanied with reducing loading oxygen concentrations, gradually approaching up to the MOC in this present work. Finally, a triangle flammability diagram with the five toluene/methanol components in our testing arrangements and conditions was established for graphically indicating the dangerous fire/explosion hazard region. It has been confirmed that this study would be very useful in relevant industrial processes for a proactive loss prevention program. The experimentally derived outcomes are recommended for the inherently safer design (ISD) for forestalling any accidents from fires and explosions.


Fire and explosion properties Inherently safer design (ISD) 20-L-Apparatus Minimum oxygen concentration (MOC) Toluene/methanol mixing solvents 

List of symbols


Boiling point, °C

(dP dt−1)max

Maximum rate of explosion pressure rise, bar s−1


Flash point, °C


Ignition energy, J


Gas or vapor explosion constant, m bar s−1


Lower explosion limit, vol.%


Minimum oxygen concentration, vol.%


Initial pressure, kPa


Corrected explosion overpressure, bar


Maximum explosion pressure, bar


Explosion overpressure, bar


Explosion class, dimensionless


Upper explosion limit, vol.%


  1. 1.
    Crowl DA, Louvar JF. Chemical process safety: fundamentals with applications. 2nd ed. NJ: Prentice-Hall; 2002. p. 252–89.Google Scholar
  2. 2.
    Chang YM, Shu CM. Flammability properties analysis of methylphenolcarbonate in diphenylcarbonate production process. J Therm Anal Calorim. 2008;93(1):135–41.CrossRefGoogle Scholar
  3. 3.
    Chang YM, Lee JC, Chen JR, Liaw HJ, Shu CM. Flammability characteristics studies on toluene and methanol mixtures with different vapor mixing ratios at 1 atm and 150°C. J Therm Anal Calorim. 2008;93(1):183–8.CrossRefGoogle Scholar
  4. 4.
    Chang YM, Lee JC, Wu SY, Chen CC, Shu CM. Elevated pressure and temperature effects on flammability hazard assessment for acetone and water solutions. J Therm Anal Calorim. 2009;95(2):525–34.CrossRefGoogle Scholar
  5. 5.
    Chen YL, Chou YP, Hou HY, I YP, Shu CM. Reaction hazard analysis for cumene hydroperoxide with sodium hydroxide or sulfuric acid. J Therm Anal Calorim. 2009;95(2):535–9.CrossRefGoogle Scholar
  6. 6.
    Hou HY, Duh YS, Lee WL, Shu CM. Hazard evaluation for redox system of cumene hydroperoxide mixed with inorganic alkaline solutions. J Therm Anal Calorim. 2009;95(2):541–5.CrossRefGoogle Scholar
  7. 7.
    Lin CP, Shu CM. A comparison of thermal decomposition energy and nitrogen content of nitrocellulose in non-fat process of linters by DSC and EA. J Therm Anal Calorim. 2009;95(2):547–52.CrossRefGoogle Scholar
  8. 8.
    Wang YW, Duh YS, Shu CM. Thermal runaway hazards of tert-butyl hydroperoxide by calorimetric studies. J Therm Anal Calorim. 2009;95(2):553–7.CrossRefGoogle Scholar
  9. 9.
    Lin SY, Tseng JM, Lee MK, Wu TC, Shu CM. Thermal runaway evaluation of α-methylstyrene and trans-β-methylstyrene with benzaldehyde. J Therm Anal Calorim. 2009;95(2):559–63.CrossRefGoogle Scholar
  10. 10.
    Chang CW, Chou YC, Tseng JM, Liu MY, Shu CM. Thermal hazard evaluation of carbon nanotubes with sulfuric acid by DSC. J Therm Anal Calorim. 2009;95(2):639–43.CrossRefGoogle Scholar
  11. 11.
    Lin WH, Wu SH, Shiu GY, Shieh SS, Shu CM. Self-accelerating decomposition temperature (SADT) calculation of methyl ethyl ketone peroxide using an adiabatic calorimeter and model. J Therm Anal Calorim. 2009;95(2):645–51.CrossRefGoogle Scholar
  12. 12.
    Petrochemical Industry of Taiwan, ROC, Pertichemical Industry Association of Taiwan, Taipei, Taiwan, ROC; 2002.Google Scholar
  13. 13.
    Yang RK, Yang CM. Practical undergraduate thesis. Department of Safety, Health, and Environmental Engineering, National Yunlin University of Science and Technology (NYUST), Yunlin, Taiwan, ROC; 2003.Google Scholar
  14. 14.
    Website of Occupational Safety and Health Administration (OSHA), US Department of Labor, USA.
  15. 15.
    Disasters Information in the Internet, the Website of ICIS Global Chemical Suppliers Search.
  16. 16.
    Chen JK. Master thesis. Institute of Safety, Health, and Environmental Engineering, National Yunlin University of Science and Technology (NYUST), Yunlin, Taiwan, ROC; 2004.Google Scholar
  17. 17.
    Chang YM, Tseng JM, Shu CM, Hu KH. Flammability studies of benzene and methanol with various vapor mixing ratios at 150ºC. Korean J Chem Eng. 2005;22(6):803–12.CrossRefGoogle Scholar
  18. 18.
    Chang YM, Hu KH, Chen JK, Shu CM. Flammability studies of benzene and methanol with different vapor mixing ratios under various initial conditions. J Therm Anal Calorim. 2006;83(1):107–12.CrossRefGoogle Scholar
  19. 19.
    Poling BE, Prausnitz JM, O’Connell JP. The properties of gases and liquids, 5th ed. McGraw-Hill International Education (Chemical Engineering Series), Appendix A, Property Data Bank, A5, A12, A 20, A27; 2001.Google Scholar
  20. 20.
    Howard WL. Encyclopedia of chemical technology, “methanol”, 4th ed., vol 16. Kirk-Othmer, New York; 1991. p. 537–57.Google Scholar
  21. 21.
    Howard WL. Encyclopedia of chemical technology, “toluene”, 4th ed., vol 24. Kirk-Othmer, New York; 1991. p. 350–89.Google Scholar
  22. 22.
    Material Safety Data Sheet (MSDS), Methanol (Methyl Alcohol), Industrial Technical Research Institute, Hsinchu, ROC; 2009.Google Scholar
  23. 23.
    Material Safety Data Sheet (MSDS), Toluene (Methyl Benzene), Industrial Technical Research Institute, Hsinchu, ROC; 2009.Google Scholar
  24. 24.
    Flammable/Combustible Liquid, NFPA 30, National Fire Protection Association (NFPA), Quincy, MA, USA; 2002.Google Scholar
  25. 25.
    Standard on Basic Classification of Flammable and Combustible Liquids, NFPA 321, National Fire Protection Association (NFPA), Quincy, MA, USA; 1991.Google Scholar
  26. 26.
    Arthur PE, Cote E, Linville JL. Fire protection handbook. 17th ed. National Fire Protection Association (NFPA), Quincy, MA, USA; 1992.Google Scholar
  27. 27.
    Shu CM, Wen PJ. Investigation of the flammability zone of o-xylene under various pressures and oxygen concentration at 150ºC. J Loss Prev Process Ind. 2002;15(4):253–63.CrossRefGoogle Scholar
  28. 28.
    Shu CM, Wen PJ, Chang RH. Investigations on flammability models and zones for o-xylene under various initial pressures, temperatures and oxygen concentrations. Thermochim Acta. 2002;392–3:271–87.Google Scholar
  29. 29.
    Yun RL, Chang YM, Lin CH, Hu KH, Shu CM. Flammability studies of 3-methyl pyridine/water system. J Therm Anal Calorim. 2006;85(1):107–13.CrossRefGoogle Scholar
  30. 30.
    Yun RL, Wan TJ, Lin CH, Chang YM, Shu CM. Fire and explosion characteristics of 3-methyl pyridine at 270ºC with high oxygen concentrations. Process Saf Environ Prot. 2007;85(3):251–5.CrossRefGoogle Scholar
  31. 31.
    Chang YM, Yun RL, Wan TJ, Shu CM. Experimental study of flammability characteristics of 3-picoline/water under various initial conditions. Chem Eng Res Des. 2007;85(7):1020–6.CrossRefGoogle Scholar
  32. 32.
    Lin CH, Chang YM, Lee JC, Lin SY, Shu CM. Effects of flammability characteristics of steam inerting to solution of acetone in water. J Therm Anal Calorim. 2008;93(1):195–200.CrossRefGoogle Scholar
  33. 33.
    Process Safety News, Laboratory Testing and Consulting for Process Safety Management, Fauske & Associates, Burr Ridge, Illinois, USA, LLC (Spring), 14, 2; 2007.Google Scholar
  34. 34.
    Kühner B. Operating instructions for the 20-L-Apparatus. Switzerland; 200(9).Google Scholar
  35. 35.
    Chang YM. Master thesis. Institute of Safety, Health, and Environmental Engineering, National Yunlin University of Science and Technology (NYUST), Yunlin, Taiwan, ROC; 2006.Google Scholar
  36. 36.
    Standard Test Method for Concentration Limits of Flammability of Chemicals (Vapors and Gases), ASTM E 681-04, American Society for Testing and Materials (ASTM), 2004, Philadelphia, PA, USA.Google Scholar
  37. 37.
    Teaching Materials, Proceeding of the Safety and Health Research and Study, Center of Environmental Protection and Safety, Ministry of Education, National Taiwan University, Taipei, Taiwan, ROC; July 2004.Google Scholar
  38. 38.
    Guide for Venting of Deflagrations, NFPA 68, National Fire Protection Association (NFPA), Quincy, MA, USA; 2002.Google Scholar
  39. 39.
    Chad VM, Crowl DA. Application of the flammability diagram for evaluation of fire and explosion hazards of flammable vapors. Process Saf Prog. 1998;17(3):176–83.CrossRefGoogle Scholar
  40. 40.
    O’Shaughnessey D, Power B. Simulating flammability under process conditions. Process Saf Prog. 1995;14(1):22–5.CrossRefGoogle Scholar

Copyright information

© Akadémiai Kiadó, Budapest, Hungary 2009

Authors and Affiliations

  • Y.-M. Chang
    • 1
  • J.-C. Lee
    • 1
  • C.-C. Chen
    • 2
  • C.-M. Shu
    • 1
    • 3
  1. 1.Doctoral Program, Graduate School of Engineering Science and TechnologyNational Yunlin University of Science and Technology (NYUST)Douliou, YunlinROC
  2. 2.Department of Occupational Safety and HealthChina Medical UniversityTaichungROC
  3. 3.Process Safety and Disaster Prevention LaboratoryDepartment of Safety, Health, and Environmental Engineering, NYUSTDouliou, YunlinROC

Personalised recommendations