| The explosive power of combustible dust is lar ge and destructive,and the process is difficult to control,which poses a great threat to the safe production of dust processing enterprises and the safety of people’s life and property.Therefore,the prevention and control work of combustible dust explosion accidents has been paid attention to by safety workers,and the prevention and control work of dust explosion has never stopped.Yellow inhibitor HN-150 dust in the process of production and processing including reaction synthesis,centrifugal separation,vacuum drying,crushing,sieving,finished product packaging process,the combustible dust cloud formed in the process,there is the possibility of burning explosion,but the current domestic research on yellow remover dust combustion characteristics of the explosion is still relatively small.There is lack of theoretical support in explosion-proof control of yellow inhibitor dust.In this paper,the physical and chemical properties of yellow inhibitor dust were analyzed,including particle size analysis and pyrolysis performance analysis.Then,using Godbert-Greenwald(G-G)heating furnace,the combustion characteristics of yellow inhibitor dust samples were tested.The influence of dust cloud mass concentration,dust particle size and dust spraying pressure on the lowest ignition temperature of dust cloud was analyzed and the combustion characteristics of yellow inhibitor dust cloud were revealed.Finally,20L explosive ball experiment system was used to test the explosive characteristics of yellow inhibitor dust and K2CO3,NH4H2PO4 and NaHCO3,and explore the synergistic explosive suppression effect of inert gas and inert material,revealing the explosive characteristics and inert explosive suppression effect of yellow inhibitor dust.The experimental results show that:(1)There are four obvious weight loss stages in the pyrolysis of yellow agent dust at the four heating rates.The weight loss rate of the latter two stages is larger than that of the first two stages,and with the increase of crucible temperature,the temperature difference before and after the weight loss stage is smaller,indicating that the weight loss stage of pyrolysis reaction is gradually continuous with the increase of temperature.As the heating rate increases,the peak weight loss rate of the curve increases,the initial extrapolation temperature of the curve decreases,the absolute value of the maximum weight loss rate Vmax increases,and the pyrolysis is more complete at the heating rate.The reason why exothermic peaks appeared at the beginning of DSC curves with the heating rate of 15K/min and 20K/min was that gas adsorption appeared at the initial stage of pyrolysis reaction with the increase of the heating rate.The smaller the mass charge ratio is,the larger the peak value of ion flow intensity curve is,and the gas product yield reaches the maximum at the end of the first weight loss stage,and again reaches the peak at the end of the third weight loss stage.CH4,CO,CH2O,N2O,CO2,NO2,C2H7N and H2O were precipitated during the pyrolysis process at a temperature rise rate of 10K/min.(2)The minimum ignition temperature of yellow agent dust cloud decreases with the increase of yellow inhibitor dust concentration.When the dust concentration continues to increase to a certain concentration,the minimum ignition temperature of yellow inhibitor dust cloud no longer decreases,and is stable at 270℃.The flame sensitive concentration of yellow inhibitor particles in the range of 60 mesh particle size is 2096g/m3.The ignition sensitive concentration of yellow inhibitor dust in the range of 160 mesh and 200 mesh particle size is 1198g/m3.When the dust concentration is small,the lowest ignition temperature is higher.When the dust concentration is lower than 150 g/m3,no matter how big the dust pressure is,the yellow agent dust will not ignite.Yellow remover the minimum ignition temperature of dust,with the increase of dust injection pressure in the three different kinds of phenomena,the first is a diameter of 60 mesh and 160 mesh yellow inhibitor dust when the concentration of 299 g/m3,minimum ignition temperature of dust presents obvious trend of increased with increment of dust spray pressure,but size is 200 mesh,appeared to reduce after rising trend;The second is that when the dust concentration continues to increase,the minimum ignition temperature of yellow inhibitor dust shows a trend of first increasing and then gradually stable with the increase of dust spraying pressure;The third phenomenon is that when the dust concentration continues to increase,the minimum ignition temperature of yellow inhibitor dust will not change with the increase of dust spraying pressure;The smaller the particle size of yellow inhibitor dust is,the lower the minimum ignition temperature of dust cloud is,the easier it is to catch fire and the more dangerous it is.(3)Under the conditions of initial ignition energy of 2kJ and ignition delay time of 60 ms,the lower limit of dust cloud explosion of yellow inhibitor with particle size of 200 mesh is:The maximum explosive pressure of dust cloud increases first and then decreases with the increase of dust cloud concentration of yellow agent from 70 to 80 g/m3.When the mass concentration of yellow agent dust reaches the most dangerous degree of 350 g/m3,the maximum explosive pressure can reach 0.850 MPa.When the dust concentration is 300g/m3,The explosive index(Kst)of yellow inhibitor dust was the largest,and Kmax reached 43.11MPa·m/s.The explosive intensity grade was ST3,and the explosive characteristic was serious.The lowest oxygen levels are 15 per cent,below which the explosion will not occur.(4)K2CO3,NH4H2PO4 and NaHCO3 can effectively suppress the explosion of yellow inhibitor dust,and the explosive suppression effect is NaHCO3>NH4H2PO4>K2CO3.When K2CO3,NH4H2PO4 and NaHCO3 can completely inhibit detonation,the addition proportion of K2CO3,NH4H2PO4 and NaHCO3 are 70%,60%and 50%,respectively.The effect of nitrogen+dust coordinated explosion suppression is more significant than that of single explosion suppression,and this kind of explosion suppression method should be adopted in industrial production process.The data and conclusions obtained in this paper can provide some theoretical guidance for the prevention of yellow inhibitor dust explosion,and have important reference significance for the safety production of yellow inhibitor production and processing enterprises. |
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