Effects of N2 and CO2 dilution on the explosion behavior of liquefied petroleum gas (LPG)-air mixtures

The present work aims to provide theoretical support to prevent LPG explosion accidents and reduce its hazardous effect. The explosion of LPG-air mixtures (4.0 % - 9.0 % in volume) under N-2 and CO2 dilution (0.0%- 30.0% in volume) was experimentally investigated by using a 20-L vessel at ambient temperature and pressure. The parameters of the maximum explosion pressure (p(max)), time to reach the maximum explosion pressure (tc), maximum rate of the pressure rise ((dp/dt)(max)), time to reach the maximum rate of the pressure rise (tb), and average velocity of flame propagation (v) were investigated. In addition, the inerting efficiencies of N-2 and CO2 were compared and analyzed. The results show that there exists a cubic function relation among pmax, (dp/dt)(max) x, t(c), t(b) and LPG volume fraction during the LPG explosion process. At the volume fraction of LPG was 5.7 %, all parameters reached peak values. The addition of N-2 and CO2 effectively suppressed the explosion of LPG, reduced pmax, (dp/dt)(max), and v and extended tc and tb. At a low LPG volume fraction, the inerting efficiency of CO2 was higher than that of N-2. At a high LPG volume fraction, the inerting efficiency of N-2 was higher than that of CO2.