Journal of Hazardous Materials 165 (2009) 1248–1252 Contents lists available at ScienceDirect Journal of Hazardous Materials j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / j h a z m a t Short communication Explosion characteristics of LPG–air mixtures in closed vessels Domnina Razus a,∗ , Venera Brinzea a , Maria Mitu a , D. Oancea b a “Ilie Murgulescu” Institute of Physical Chemistry, 202 Spl. Independentei, 060021 Bucharest, Romania b Department of Physical Chemistry, University of Bucharest, 4-12 Regina Elisabeta Blvd., 030018 Bucharest, Romania a r t i c l e i n f o Article history: Received 8 January 2008 Received in revised form 19 September 2008 Accepted 22 October 2008 Available online 28 October 2008 Keywords: LPG (liquefied petroleum gas) Combustion Closed vessel Explosion pressure Rate of pressure rise Explosion time a b s t r a c t The experimental study of explosive combustion of LPG (liquefied petroleum gas)–air mixtures at ambi- ent initial temperature was performed in two closed vessels with central ignition, at various total initial pressures within 0.3–1.3 bar and various fuel/air ratios,within the flammability limits. The transient pressure-time records were used to determine severalexplosion characteristics of LPG–air: the peak explosion pressure,the explosion time (the time necessary to reach the peak pressure), the maximum rate of pressure rise and the severity factor. All explosion parameters are strongly dependent on initial pressure of fuel–air mixture and on fuel/air ratio. The explosion characteristics of LPG–air mixtures are dis- cussed in comparison with data referring to the main components of LPG: propane and butane, obtained in identical conditions. © 2008 Elsevier B.V. All rights reserved. 1. Introduction LPG is extensively used nowadays,both as alternative fuel in automotive engines and as domestic fuel. In comparison with con- ventional engine fuels (gasoline and diesel), LPG is considered an attractive alternative fuel since its combustion in air is character- ized by reduced emissions of NO x , CO and unburned hydrocarbons [1]. A thorough analysis and prediction of engines’ and/or combus- tors’ performance requires a systematic investigation of explosion characteristics of LPG in air in various conditions. Values of flamma- bility limits for LPG in air were reported by Mishra and Rahman, for a LPG blend containing 70% propane and 30% butane [2]. Flame propagation in LPG–air mixtures with various equivalence ratios, in operating conditions close to a heavy-duty LPG engine (initial pres- sures between 1.5 and 4 bar, initial temperatures between 330 and 380 K) was studied by Lee and Ryu [3]. The authors examined the pressure and temperature influence on flame propagation speed for LPG–air, in comparison with propane–air mixtures, well char- acterized in this respect. Burning velocities of LPG–air without or with exhaust gas addition are also reported by Liao et al. [1,4] from optical records of flame front position, in experiments made at vari- ∗ Corresponding author. Tel.: +40 21 316 79 12; fax: +40 21 312 11 47. E-mail addresses: drazus@yahoo.com, drazus@icf.ro (D. Razus), venerab@icf.ro (V. Brinzea), maria mitu@icf.ro (M. Mitu), doan@gw-chimie.math.unibuc.ro (D. Oancea). ous initial pressures and temperatures in a 1.57 L closed vessel with rectangular profile and central ignition.The authors discuss their results versus similar data referring to propane– and i-butane–air mixtures [4]. Other experiments, made in a 2.46 L cylindrical ves- sel with central ignition used LPG– and propane–air mixtures with variable initial composition, pressure and temperature [5]. Values of several explosion characteristics of closed vessel combustion (maximum explosion pressure, maximum rate of pressure rise, time to maximum pressure, time to maximum rate of pressure rise, ignition delay period, severity factors) are given for both fuels and examined against initial pressure,temperature and composition. For all explosion parameters, the dependencies on initial pressure, temperature and equivalence ratio are given both as diagrams and fit equations, able to be used for comparison with other sets of data. Burning velocities of propane–, n-butane– and LPG–air mix- tures, determined from pressure-variation during the early stage of propagation in a closed spherical vessel with central ignition by means of cubic law coefficients, were recently reported for mixtures of variable initial composition and pressure [6]. The present work completes the data on burning velocities [6] with values of explosion parameters of LPG–air in two highly sym- metrical closed vessels, at room temperature, at various initial pressures within 0.3–1.3 bar and various [LPG]/[O 2 ] ratios: the peak (maximum) explosion pressures p max , the times to peak pressures max , the maximum rates of pressure rise (dp/dt) max and the sever- ity factors K G . LPG is a blend used in Romania for domestic use containing 12 vol.% propane, 87 vol.% butane, 1 vol.% pentane. The 0304-3894/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.jhazmat.2008.10.082