Research On The Performance Of Solid Powder To Suppress Methane Explosion And Mechanism In Pipeline Network

Methane has brought many conveniences to the national economy and people’s life,but the explosions induced by methane leakage during daily transportation have greatly threatened people’s life health and national property safety.To address this problem,a combination of experimental research,analogue simulation and theoretical analysis was used in this dissertation to study the explosion suppression performance and explosion suppression mechanism of four solid powders potassium bicarbonate,ammonium dihydrogen phosphate,montmorillonite and palygorskite on the methane explosion in the pipe network.The conclusions can provide theoretical support for improving the safety of methane transportation and reducing the loss of methane explosion accidents.Experimental research on the propagation characteristics of methane explosion in pipe network was carried out based on methane explosion experiment under the independently developed pipe network system for combustible gas explosion.Explosion overpressure peak,explosion power index,explosion flame propagation velocity and explosion flame temperature were used as the characteristic parameters.Based on the multiple nonlinear regression model study,the characteristic function relationship between the peak of explosion overpressure and the explosion power index within different propagation distance was obtained.Then,the experimental phenomenon was analyzed to obtain the propagation characteristics of methane explosion overpressure and explosion flame.Experimental research on solid powder explosion suppression was carried out based on the methane explosion suppression experiment with the four powder inhibitors of ammonium dihydrogen phosphate,potassium bicarbonate,palygorskite and montmorillonite under the independently developed pipe network system for combustible gas explosion.The particle size and powder mass of the inhibitors were modified to study the explosion suppression performance under different powder particle sizes and powder mass conditions,so as to obtain the best powder particle size and powder mass of the four solid powders for suppressing the propagation characteristics of methane explosion in pipe network are 61-72 μm and 60 g,respectively.A simulation study of the damage characteristics of methane explosion in the pipe network was conducted based on the explosion relief baffles at the outlets on both sides of the pipe network using the dynamics simulation software ANSYS-LS/DYNA.The changes of explosion stress and impact strain with time were studied and the mechanism of the impact load of the methane explosion was elaborated on and analyzed for dynamic damage characteristics of the methane explosion impact load on the fixed facilities in the pipe network.A simulation study of solid powder explosion suppression was carried out through the dynamical simulation software ANSYS-LS/DYNA.The maximum stress value and maximum strain value of the explosion relief baffles under different powder parameter working conditions.so as to obtain the particle size and mass of four solid powders with the best performance in suppressing the dynamic damage of pipeline network methane explosion are 61-72μm and 60 g,respectively.Experimental research on powder thermal characteristics and molecular dynamics simulation study were conducted for thermal decomposition characteristics of four powder inhibitors to clarify their physical explosion suppression mechanism and explosion suppression performance difference.The molecular dynamics software VASP and Gaussian were used to study the molecular surface electrostatic potential distribution,transition state energy barrier and Gibbs free energy barrier of the four powder inhibitors in the explosion suppression process,so as to reveal the chemical explosion suppression mechanism and explosion suppression performance differences of the inhibitors from the microscopic perspective.The research on the suppression performance and explosion suppression mechanism of solid powder on methane explosion in pipe network is of great significance to further improve the safety of methane transportation and effectively reduce accident damage and property loss caused by methane explosion.There are 119 figures,26 tables,and 203 references in this dissertation.