Safety And Reliability Study Of Explosion Venting Process

In order to avoid the secondary hazard caused by the explosion venting,safety and reliability of venting process was studied based on porous media.Porous media has attenuation effect of flame temperature and explosive overpressure.Using FLUENT fluid dynamics software,the gas explosion in spherical vessel vented into a dump vessel was simulated by changing the parameters of porous media.To analyze the evolution of temperature and pressure,the effect of porous media on venting flame propagation was studied.The results show that compared with no porous media,temperature and pressure reduced obviously.It can be concluded that the presence of the porous media helps to reduce explosion intensity effectively.When the porous media is on the left,it leads to a better protection function than that on the right.The peak pressure in venting vessel and dump vessel reduced by 4.1%and 24.7%respectively.The thicker the porous media,the lower the peak pressure in the dump vessel.The peak pressure in the venting vessel and the dump vessel reduced by 7.2%and 41.2%respectively when the thickness of porous media reaches 20mm.To some extent,the peak pressure in the dump vessel reduces with the increase of the length of porous media.When the length of porous media reaches 900 mm,further increase of the length won’t produce any more significant effect on the peak pressure in the dump vessel.Compared with continuous porous media,the peak pressure in the dump vessel reduced by 12.1%with segmented porous media.Thus,in actual gas explosion venting dump protection design,porous media is a good explosion suppression structure.The best choice should consider the length and the thickness of porous media.Segmented porous media leads to a better protection function on the gas explosion venting dump process.Acording to the effect of porous media on venting flame propagation and quenching heating theory of porous media,two kinds of quenching structure for different explosion intensity were obtained.Through the explosion testing on the vessel of 2.7m³,the blocking effect of quenching structure was gained.The presence of quenching structure raises the reduced pressure about 10%.And the study showed that the structure parameter of quenching had close relationship with three explosion parameters including explosion index,redundant pressure and volume of venting vessel.The greater the K_st,the greater the structure paramters of queching.When the reduced pressure reaches 0.07MPa,only type II quenching can extinguish fire.The relationship between amount of quenching powder and reduced pressure was obtained when the reduced pressure ranges from 0.07MPa to 0.25MPa.Based on scaled cube root law,the structure parameters of quenching in industry application were acquired.