Explosion Characteristics Of Sulfide Dust And Multi-physics Coupling Analysis

The sulfide mineral dust produced by high-sulfur metal mines is likely to accumulate on the roadway surface and float in the air,forming sulfide ore dust clouds and sulphide ore dust clouds,respectively.Sulfide mineral dust(dust layer,ore cloud)is prone to spontaneous combustion or explosion in the high-temperature environment downhole,and the resulting downhole fires cause significant loss of personnel and equipment.In order to further study the characteristics of sulfide dust explosion in sulphide ore,the parameters of sulfidation dust explosion intensity(maximum explosion pressure,maximum explosion pressure rise rate)and explosion sensitivity parameters(minimum ignition energy,minimum ignition temperature)with the influencing factors,This paper provides a basis for the prevention of sulfide dust explosion in sulfur-bearing metal mines.Based on the theory of dust explosion and previous studies,this paper carries out experiments on sulfide dust explosion intensity,minimum ignition energy experiment,and minimum ignition temperature experiment.The COMSOL Multiphysics software was used to analyze the temperature field and gas-solid two-phase flow field of a 20 L blast ball injected with sulfide dust.The specific research content is as follows:(1)In the 20 L explosion ball,experiments were conducted on the explosion intensity of sulfide dusts with different sulfur content and different particle sizes.It was found that the three types of sulfide dusts A,B,and C could all be exploded,while the dusts of Class D sulfide dust did not explode;The maximum explosion pressures of the three types of sulfide dusts were respectively 0.33 MPa,0.24 MPa,and 0.16 MPa.The maximum explosion pressure rates were 32.12MPa/s,28.34MPa/s,and 15.59MPa/s,respectively.It can be seen that the sulphur content has a significant effect on the parameters of the sulphide dust explosion intensity;in theory: the maximum explosion pressure of the sulphide ore,the maximum explosion pressure increase rate is proportional to the specific surface area,and inversely proportional to the particle size and dispersion.With the increase of mass concentration,the law first increases and then decreases;however,with the increase of mass concentration,fine particle dust tends to agglomerate,which changes the particle size,specific surface area and dispersion of sulfide ore dust,and affects the sulphide ore.Dust explosion intensity parameters of the law: usually sulphur content,particle size,specific surface area,dispersion and mass concentration affect the sulfide dust explosion characteristics;The fitting results show that the continuous combustion time of sulfide dust is consistent with the variation of mass concentration to satisfy the Sine Damp equation;(2)The minimum ignition energy of each group of sulphide ore was tested in a 20 L explosion ball with a chemical igniter.The minimum ignition energy of each group of sulphide ore dust was: A500 group 3 ~ 4 kJ,B500 group 6 ~ 8 kJ,C500 group> 12 kJ;A300 group 2 ~ 3kJ,B300 group 4 ~ 6kJ,C300 group> 12kJ;A200 group 2 ~ 3kJ;B200 group 6 ~ 8kJ;C200 group> 12kJ;Using Logistic model analysis,the minimum ignition energy of sulfide dust at different ignition probabilities was obtained,and more accurate results than other calculation methods were obtained;the higher the sulfur content of the sulfide dust cloud,the higher the sulfur content of the gaseous sulfur generated during ignition.More,the more sufficient heat is released from the sulfur combustion,the less energy that the sulfide dust needs to be supplied by the ignition head,ie,the minimum ignition energy;(3)The minimum ignition temperature test of sulfide ore dust cloud and sulphide ore dust cloud was carried out on hot plate and G-G furnace respectively.The results showed that the lowest ignition temperature of sulphide dust layer was 430 °C,and the lowest ignition temperature of sulphide dust cloud was 386 °C.The analysis shows that the order of the factors affecting the minimum ignition temperature of the sulphide ore cloud is sulphur content> particle size> mass concentration> spray pressure;The higher the sulfur content of the sulphide ore cloud,the lower the mass concentration,and the lower the dust pressure,the lower the minimum ignition temperature.Under a certain particle size condition,the maximum sulfidation dust cloud minimum ignition temperature exists;(4)Using COMSOL Multiphysics software to analyze the temperature field and the gassolid two-phase flow field during the injection of sulfide dust into the 20 L explosion ball,it was concluded that the velocity distribution map and the particle motion path diagram of the sulfide ore dust injected into the 20 L explosion ball within 60 ms are in accordance with the actual situation.Therefore,the reasonable ignition delay time for the experiment of sulfide dust explosion intensity is 60 ms,and the movement law of sulfide dust in 20 L explosion ball is mainly controlled by the gas-solid two-phase flow field.