Coupling Propagation Law Of Dust Collector Explosion Along Venting Surface And Dust Removal Pipeline

The dust removal system is the initial high-incidence area of industrial dust explosion accidents.The explosion disaster of the main body of the dust collector is usually released to the outside of the dust collector through the explosion venting.At the same time,it propagates upstream of the process along the air inlet duct.The two-way propagation of explosion disasters along the pipeline and the venting surface is likely to interact,which aggravates the complexity of the explosion disaster process of the dust removal system and restricts the scientific assessment and precise prevention and control of explosion disasters.Based on this,this paper systematically studies the entire evolution process of explosion disasters in typical dust removal systems using the CFD technology.The quantitative influence of factors such as the venting area,the static activation overpressure,the inner diameter of dust removal pipeline,and the dust cloud concentration on the explosion disaster of the main body of the dust collector,the dust removal pipeline,and the outside of the removal system was analyzed.The coupling propagation mechanism of explosion disaster along the venting surface and the dust removal pipeline is explained.(1)Characteristics of internal explosion overpressure of the dust collector under the influence of the coupling between the venting surface and the dust removal pipeline.There is an interaction between the two-way propagation process of the explosion disaster along the venting surface and the dust removal pipeline,which induces the internal explosion overpressure of the dust collector to present a "three peaks" characteristic with time.The first overpressure peak is caused by the first explosion venting caused by the opening of the venting surface,which is approximately equal to the static activation overpressure of the venting surface and is not significantly affected by other factors.This peak can evolve into the maximum reduced explosion overpressure when the size of the venting surface and the static activation overpressure are large,and the inner diameter of the pipeline,the dust cloud concentration are small.The second overpressure peak is caused by the continuous combustion inside the dust collector and the spread of the dust pipeline after the vent surface is opened.It is positively correlated with the inner diameter of the pipeline and dust cloud concentration.This peak can evolve into the maximum reduced explosion overpressure when the inner diameter of the pipeline and the dust cloud concentration are large,and the size of the venting surface is small.The third overpressure peak is relatively small,which is formed by further continuous combustion in the dust collector and has a negative and positive correlation with the inner diameter of the dust removal pipeline and the dust cloud concentration,respectively.(2)The propagation law of explosion disaster along the dust removal pipeline induced by the explosion venting.The opening of the explosion venting surface has a significant impact on the disaster propagation process of the dust removal pipeline,which is mainly reflected in the reaction of the secondary explosion outside the explosion venting surface.It hinders the continuous release of explosion energy along the venting surface,thereby potentially aggravating the overpressure increase and flame acceleration in the dust removal pipeline.The maximum explosion overpressure and instantaneous flame propagation velocity in the dust removal pipeline are positively and negatively correlated with the opening pressure and the size of the venting surface,respectively.The unburned dust inside the dust collector enters the dust removal pipe and causes a secondary explosion.The secondary explosion intensity is positively related with the pipe diameter.(3)The propagation law of external disasters on the explosion venting surface induced by dust removal pipeline.The explosion disaster spreads along the dust removal pipeline to form pressure accumulation,and the accumulated pressure reacts inside the dust collector,aggravating the complexity of explosion venting disaster.The external disasters of the explosion venting surface are mainly manifested as explosion overpressure,high temperature flame and high-speed airflow.The external overpressure generally takes the form of a turbulent oscillation peak group,and the overpressure peak gradually decays along the propagation distance.The flame is jetted out from the venting surface,and the maximum flame propagation distance outside can reach 8～12 m.The dynamic pressure formed by the explosion venting causes high-speed airflow outside the venting surface,and the wind speed can reach 143.8～494.5 m/s,which is equivalent to 4～15 times the hurricane.The maximum explosion overpressure,maximum wind speed,and maximum flame propagation distance outside the explosion venting surface are positively parabolic,positively correlated and negatively correlated with the inner diameter of the dust removal pipeline,respectively.