Experimental Study On Explosion Characteristics And Explosion Suppression Technology Of Liquefied Petroleum Gas

Liquefied petroleum gas（LPG）is a multi-component gas mixture with main components of C₃ and C₄.It is mainly used in residential life,non-ferrous metal smelting,kiln roasting and automobile fuel.However,once LPG leaks,it encounters ignition source or high temperature,which is extremely easy to cause fire or explosion accidents and cause great harm.Studying the explosion characteristics and explosion suppression methods of LPG is particularly important for the prevention and control of LPG explosion accidents.Therefore,this thesis uses a 20-litre spherical explosion test device to study the explosion characteristics of LPG and the effect of different materials on explosion suppression.The specific research contents and conclusions are as follows:（1）The explosion limit of LPG at room temperature and pressure,the variation of explosion characteristic parameters of different concentrations of LPG and the propagation characteristics of explosion flame were studied.The experimental results show that the explosion limit of LPG is（2.25%,9.25%）.With the increase of LPG concentration,the P_ex and（d P/dt）_ex increase first and then decrease,reaching the maximum values of 0.714MPa and 33.073MPa/s at 4%LPG.The t_b and t_c decrease first and then increase,reaching the minimum values of 200.0ms and 127.0ms at4%LPG.At low concentration of LPG,the explosion flame is bright and diffuses from the center of the ignition electrode to the inside of the container.At high concentration of LPG,the flame color is dim,burning from the top of the explosion ball and gradually spreading downward,and the flame shape is irregular.（2）The experimental study on the inhibition of LPG-air mixture explosion by single inert gas and inert powder was carried out.The experimental results show that with the increase of inert medium,the P_ex and（d P/dt）_ex decrease,and the t_b and t_cincrease.When 37%CO₂ or 40%N₂ is added,the LPG explosion is completely suppressed,and the explosion suppression effect of CO₂ is always better than that of N₂.When adding the same mass concentration of inert powder,the explosion suppression effect is as follows:Na HCO₃>Al（OH）₃>Si O₂.（3）The experimental study of LPG explosion by compound powder and gas/solid two-phase inhibitor was further carried out.The results show that the two-phase inhibitors can inhibit LPG explosion,and the more the addition amount,the more obvious the explosion suppression effect.The compound powder with Na HCO₃ addition has better explosion suppression effect.The explosion suppression effect of the three compound powders is as follows:Na HCO₃/Al（OH）₃>Na HCO₃/Si O₂>Al（OH）₃/Si O₂,but the explosion suppression effect is less than that of single Na HCO₃ powder,and there is no good synergistic explosion suppression effect.The explosion suppression effect of the two gas/solid two-phase inhibitors increases with the increase of CO₂ volume fraction or Na HCO₃ and Al（OH）₃ mass concentration.Among them,CO₂/Na HCO₃ has better synergistic explosion suppression effect than CO₂/Al（OH）₃,and the greater the volume fraction of CO₂,the more obvious the synergistic explosion suppression effect.At the same mass concentration of 500g·m^-3 powder,10%CO₂/Na HCO₃ has the best explosion suppression effect and can completely inhibit LPG explosion.The results of this thesis provide a new understanding of LPG explosion characteristics and LPG explosion suppression,and have theoretical and practical significance for LPG explosion accident prevention and control.There are 35 pictures,4 tables,and 110 references.