Experimental Study On The Explosion Characteristics Of Methane,Acetone And N-heptane

With the rapid development of industrial level,combustible gases and vapors have been widely used in production,storage and transportation processes.However,the resulting explosion accidents also caused huge casualties and property damage.Therefore,it is of great significance to study and analyze the explosion properties of these substances for the prevention of explosion accidents.At present,researches in both China and abroad are mainly based on the experimental measurements of explosion characteristics of combustible gases and vapors.Moreover,most of the experiments were performed in macroscopic static state,and the study of change rule of explosion characteristics of combustible gases and vapors in flow state is insufficient.An improved 20 L spherical explosion vessel test system was used to measure the explosion characteristics of methane,acetone and n-heptane in macroscopic static and flow states.The fitting curves were constructed to analyze the change rule of each characteristic,and the explosion hazard and destructiveness of three combustible substances were evaluated.Some academically significant research results have been achieved:(1)The experiments investigated the effects of initial vacuum degree and flow state in the vessel on the explosion characteristics of methane.The explosion characteristics of methane with different concentrations were measured at initial vacuum degrees of 0.2,0.4,0.6 and 0.8 bar.The results showed that with the decrease of initial vacuum degree,the explosion pressure and rate of pressure rise increase under various operating conditions,and the corresponding experimental deviation decreases.The explosion characteristics of methane with different concentrations were measured in macroscopic static and flow states.The results showed that as the concentration increases,the explosion pressure and rate of pressure rise of methane in both states show a trend of increasing first and then decreasing,and the optimal explosive concentration is 11%(the most hazardous concentration).In addition,the maximum explosion pressure of methane increases slightly in flow state,while the maximum rate of explosion pressure rise and deflagration index increase significantly.(2)The experiments obtained the explosion characteristics of acetone and n-heptane vapors in macroscopic static and flow states,and the effects of flow state on the explosion characteristics of two vapors were contrastively analyzed.The explosion characteristics of acetone and n-heptane vapors with different concentrations were measured in macroscopic static and flow state.The results showed that with the increase of concentration,the explosion pressure and rate of pressure rise of acetone and n-heptane vapors show a trend of increasing first and then decreasing.The optimal explosive concentrations are 6% and 4%,respectively.Besides,the maximum explosion pressure of both acetone and n-heptane vapors increases slightly in flow state,while the maximum rate of explosion pressure rise and deflagration index increase significantly.(3)Fitting curves were constructed to analyze the change rules of explosion characteristics of methane,acetone and n-heptane measured in macroscopic static and flow states.The explosion hazard and destructiveness of three substances were discussed,and suggestions for preventing explosions were proposed.The results showed that the fourth-order polynomial curve can accurately fit the explosion pressure-concentration relationship of three substances,and the Gaussian curve can accurately reflect the change rule of the rate of explosion pressure rise of three substances with concentrations.Besides,in both states,the maximum explosion pressure,maximum rate of explosion pressure rise and deflagration index of n-heptane vapor are higher than those of methane and acetone vapor,which proves that n-heptane vapor is the most explosive and destructive among three substances.When storing combustible gases and vapors,it is necessary to design explosion-proof containers reasonably,monitor the concentration of combustible substances strictly,and avoid being in a flowing environment.