Experimental Study On The Suppression Effect Of Mineral Powder On Wheat Starch Explosion

With the development of modern industry,the number of powder-related companies has increased,and dust explosion accidents have also increased.Among the combustible dust that can cause dust explosion accidents,grain dust accounts for a relatively large proportion.Therefore,research on solid inerting or explosion suppression of grain dust explosion is of great significance for reducing the probability and losses of such accidents.In order to seek a solid explosion suppressant that can effectively suppress grain dust explosion and is environmentally friendly and economical,the effect of dust concentration of wheat starch on the maximum explosion pressure and the maximum rate of pressure rise is tested by spherical 20 L explosion chamber.Based on the optimal explosion concentration of wheat starch,the suppression effects of three mineral powders of diatomaceous earth,montmorillonite and 4A zeolite on wheat starch explosion are compared and the suppression mechanisms of three mineral powders are also analyzed,combining with the physical and chemical properties of wheat starch and mineral powders.In addition,the minimum explosive concentration of wheat starch is explored.The results show that:(1)Under the experimental conditions,the maximum explosion pressure and the maximum rate of pressure rise of wheat starch both first increase and then decrease with the increase of dust mass concentration.When the concentration is 500 g/m~3,they reach the maximum value of 0.726 MPa and 63.075 MPa/s,respectively.The minimum explosive concentration of wheat starch is 50～60 g/m~3.(2)With the increase of the mass of diatomaceous earth,the maximum explosion pressure and the maximum rate of pressure rise of wheat starch both decrease.When the mass of diatomaceous earth is 10 g,they drop sharply to 0.1046 MPa and 8.8077MPa/s,and the decrease is the largest at this time.Compared with the non-added diatomaceous earth,the reductions are 85.54%and 86.04%,respectively.(3)With the increase of the mass of montmorillonite,the maximum explosion pressure and the maximum rate of pressure rise of wheat starch gradually decrease.When the mass of montmorillonite is 10 g,the decrease is the largest,and they finally drop to 0.1057 MPa and 8.8080 MPa/s.Compared with those without montmorillonite,they are reduced by 85.40%and 86.04%,respectively.(4)With the increase of the mass of 4A zeolite,the maximum explosion pressure and the maximum rate of pressure rise of wheat starch both decrease.When the mass of 4A zeolite is 1.0 g,they drop sharply to 0.1167 MPa and 11.649 MPa/s,and the decrease is the largest at this time.Compared with the non-added 4A zeolite,the reductions are 83.89%and 81.53%,respectively.(5)The order of suppression effect of three mineral powders is:4A zeolite>montmorillonite>diatomaceous earth.Considering price and suppression effect of mineral powders,diatomaceous earth is more economical than montmorillonite.Diatomaceous earth can weaken explosion intensity of wheat starch through physical effect,including cooling,dilution,heat insulation and collision destruction of free radicals.Montmorillonite can weaken wheat starch explosion by physical and chemical effects,relying on cooling,dilution and surface collisions to absorb free radicals.The physical suppression effect of 4A zeolite includes cooling,dilution and radiation absorption,and its chemical suppression effect includes surface collision adsorption and sodium ion consumption of free radicals.