Influences Of Methane And Propane On The Explosion Characteristics Of PMMA And ABS Dusts

Polymethyl methacrylate?PMMA?and Acrylonitrile butadiene Styrene copolymers?ABS?are important industrial raw materials.During the industrial production process,they are mixed with combustible gas and exploded.The risk of accidents is gradually increasing.In order to prevent such explosion accidents and reduce the damage degree of explosion accidents,it is urgent to improve explosion theory and understand the mechanism of action.In this paper,in the 20L spherical explosive device,the chemical ignition method is used to study the variation of the lower explosion limit,maximum explosion pressure and explosion index of methane/PMMA,methane/ABS,propane/PMMA,propane/ABS mixture.This article first tested the explosive properties of single-phase combustibles and four two-phase mixtures under the conditions of air pressure 0.101MPa and temperature10?in a standard 20L spherical explosive device.The lower explosion limits of methane and propane are 5.1%and 2.1%of propane respectively,and the lower explosion limits of PMMA and ABS dust are 100g/m³ and 120g/m³ respectively;the maximum explosion pressures of the four combustibles are 0.74MPa and 0.81MPa respectively,0.60MPa and 0.58MPa;the explosion index is 151.77MPa·m/s,and249.36MPa·m/s,37.53MPa·m/s and 36.91MPa·m/s.It shows that the explosion hazard of propane is higher than that of methane.The explosion sensitivity of ABS dust with a median particle size of 40.6?m is slightly lower than that of PMMA powder with a median particle size of 15.7?m.The explosion intensity of PMMA and ABS dusts is not much different,and the explosion index All belong to the weaker level of St1.Secondly,the effect of methane and propane on the lower explosion limit of PMMA and ABS dust was studied.The addition of combustible gas significantly reduces the minimum explosive concentration of the two types of dust,and the combustible gas at a safe concentration and the dust at a safe concentration are still explosive.By comparing and analyzing the effects of methane and propane on the lower explosion limit of PMMA and ABS dust,it can be found that the effect of propane on the lower explosion limit of dust is more effective.That is,when PMMA and ABS dust are mixed with propane,they are more dangerous than methane.At the same time,the applicability of three classic gas-powder mixture explosion lower limit prediction models in this study is analyzed.The results show that the Bartknecht model has a certain reference value for the prediction of the lower explosion limit of the four gas-powder two-phase mixtures,but the predicted value is slightly conservative;Le Chatelier and Jiang models have large errors,and their predicted values are not applicable.Then the effects of methane and propane on the explosion strength parameters of PMMA and ABS dust were studied.With the increase of the concentration of methane and propane,the explosion pressure parameters such as the maximum explosion pressure P_max,the maximum explosion pressure rise rate?dP/dt?_max and the explosion index of the dust are also increasing,but the increase trend is gradually flattening.For the maximum explosion pressure and explosion index,single-phase methane and propane are higher than the two-phase mixture of gas and powder,but both are higher than single-phase PMMA and ABS dust.The maximum explosion index K_H of the four gas-powder mixtures in this paper exceeds 30MPa·m/s,that is the mixing of methane and propane makes the PMMA and ABS dust explosion levels change from the weaker St1 level to the St3 level.The paper has 42 pictures,27 tables and 78 references...