Experimental Study On The Characteristics Of Suppressing Flour Explosion By Inert Medium

With the acceleration of industrialization,powder technology has been widely used in various industries.However,frequent dust explosion accidents are a major factor restricting the development of the industry.Among them,the grain dust explosion accident rate is high,the danger is big,the consequence is serious.In order to understand the explosion principle,and find out the inert medium which can effectively inhibit the explosion intensity of flour.In this paper,the effects of flour concentration,ignition energy and flour particle size on explosion intensity were studied by using a 20 L spherical explosive apparatus,and selects four inert media sodium bicarbonate,ammonium dihydrogen phosphate,aluminum hydroxide and calcium carbonate to suppress the explosion intensity of flour.The particle size distribution of flour and inert dust was tested by particle size analyzer,and the pyrolysis characteristic parameters of dust were tested by thermogravimetric analyzer,which provided theoretical basis for the explosion suppression principle of inert dust.The results are as follows:(1)with the increase of mass concentration,the maximum explosion pressure and the maximum pressure increasing rate of flour first increase and then decrease,and the maximum explosion pressure of flour reaches at the concentration of 400 g/m3-500 g/m3;the maximum pressure increasing rate reaches at the concentration of 400 g/m3-600 g/m3;(2)With the increase of ignition energy,the maximum explosion pressure and the maximum pressure rise rate of flour increase linearly;(3)In the experimental range,flour dust with smaller particle size has larger maximum explosion pressure and maximum pressure rise rate,that is,the dust with smaller particle size has higher explosion risk;(4)Sodium bicarbonate,ammonium dihydrogen phosphate,aluminum hydroxide and calcium carbonate all have inhibitory effect on flour.Due to the influence of particle size and pyrolysis characteristics of inert dust,calcium carbonate has the best inerting effect when the mass fraction of inert dust is less than 30%,while sodium bicarbonate has the best inerting effect when the mass fraction of inert dust is more than 30%;(5)Because ammonium dihydrogen phosphate and sodium bicarbonate are physical-chemical synergistic explosion suppression,they have better explosion suppression effect.Further refinement of their particle size.The results show that ammonium dihydrogen phosphate has a greater impact on the maximum explosion pressure of flour,while sodium bicarbonate has a greater impact on the maximum pressure rise rate.