Study On Dust Explosion-proof Modification And Discharge Technology Of An Insulated Box Factory

As combustible dust,wood dust is often associated with the form of fine particles in wood processing industry.In the process of production,not only will the physical health of field workers suffer from the explosion of wood dust,but the high concentration of dust may cause dust explosion,which affects the safety of enterprise production.The rationality of workshop ventilation and dust removal system is an important technical premise to solve the above problems.Explosion drainage and explosion isolation technology is the most effective protection technology means at present.In order to better prevent the occurrence of wood dust explosion accidents,this paper selects an insulated box production workshop as an engineering application case,hoping to pass the theoretical basis for practical engineering through research.The specific research content mainly includes the following aspects:?1?Experimental study on explosive characteristics of wood dust.Taking wood dust in insulated box workshop as the test object,explosive characteristic parameters of dust were tested by hartmann tube,20L ball,minimum ignition temperature tester of dust layer and other instruments.Test for dust cloud minimum ignition temperature of 633.15K,the minimum ignition temperature of dust layer is greater than 563.15K,the dust cloud minimum ignition energy between 849.3 mJ to 1142.7 mJ,dust clouds lower explosive limit concentration in 10g/m³,20 g/m³,between dust cloud,the maximum explosion pressure is 10 bar,dust cloud maximum explosion pressure rise rate is 93 bar·m/s.?2?Using professional software WinVent4.0 and standard GB/T 15605-2008,European standard EN 14491 and American standard NFPA 68,the explosion-release area of the dust collection system of the insulated box factory is calculated,and the technical plan of explosion-release instead of flame-proof is developed,and the area of explosion-release through pipes is calculated.It is calculated that the explosion-discharging area of the dust collector is 2.30m²,and the explosion-discharging area inside the pipe needs at least 0.24m².?3?Establish mathematical and physical models.Based on practical engineering problems,FLACS10.5 was used to simulate the technical scheme of detonation relief instead of flameproof.Seven groups of different initial conditions were set up for simulation to study the influence of different ignition positions and initial dust cloud states on the propagation of explosion flame,explosion overpressure,special points and pressure of explosion relief plate.?4?Simulation results of different ignition positions show that:?1?The leakage plate in the pipeline is mainly affected by negative pressure;?2?The ignition position on the impact of pressure on the two leakage plates in the pipeline mainly depends on whether the horizontal distance between the two changes:the horizontal distance of the ignition position is constant when the pressure on the two leakage plates in the pipeline is almost constant;When the horizontal distance is changed,the negative pressure value of the release plate in the pipeline is almost unaffected.The farther the ignition position is from the blow-out plate in the pipe,the greater the overpressure on the blow-out plate will be.?3?In the simulated situation,the closer the ignition position is to the bottom of the dust collector,the faster the flame travels to the pipe,and the faster it travels in the pipe.The farther away the ignition is from the blowout pipe,the slower the flame travels to the pipe,but the faster the flame travels through the pipe.?4?The closer the discharge plate from the ignition position,the more vulnerable to the negative pressure on the surface of the external container;Conversely,the greater the distance,the more susceptible the vessel is to the overpressure effect of dust explosion.?5?The simulation results of different initial dust cloud distribution states show that:when dust cloud is only distributed in the lower half of the dust remover,the overpressure borne by Panel 1 and Panel 2 in the pipeline is the maximum,and when dust cloud is only distributed in the upper half of the dust remover,the overpressure borne by Panel 1 and Panel 2 is the minimum.It also shows that the dust cloud formed in the lower part of the dust remover is the most harmful to the workshop under the initial condition.?6?In all simulated scenarios,the opening delay of the release plate occurred.When the explosion pressure reached P_stat,the maximum explosion overpressure in the system did not vary greatly due to the change of ignition position.When the pressure reaches about 0.15bar,the initial condition becomes the key factor to control the peak pressure.