Identification Of High Consequence Area Of Oil And Gas Pipeline And Risk Assessment Of Pipeline Failure

In view of the more and more complex structure of buildings in modern times,as a new generation of halon fire extinguishing agent substitute,ultrafine dry powder can effectively cope with various environment in the building due to its excellent dispersion.Three kinds of potassium salt were selected as the base material to prepare the ultrafine dry powder with the average particle size less than 20 microns.Because the superfine dry powder is easy to agglomerate because of the increase of specific surface energy,it will not be conducive to the fire extinguishing performance of the superfine dry powder.Therefore,the mechanical chemistry method is used to adsorb3%hydrophobic nano silica onto the surface of potassium hydrogen carbonate powder,which can effectively reduce the particle size and improve the fluidity and hydrophobicity of the powder;The results show that the powder has small particle size,good dispersion performance,good hydrophobic property and high loose density.In order to study whether the modifier can further improve the fire extinguishing performance of dry powder,the flame retardant methyl phosphate two methyl ester(DMMP)was coated onto the dry powder surface by sol-gel method and refined for two times.The coating results were analyzed by scanning electron microscope(SEM)and X ray diffractometer(XRD)and the fire extinguishing ability was tested.The results show that the DMMP can be effectively coated on the dry powder surface by sol-gel method,and the particle size of the dried powder after refine is smaller,and its extinguishing performance is more effective than that of the ultrafine dry powder directly fined.Inert gas is often used as driving gas in powder fire extinguishing technology.In order to improve the fire extinguishing technology of powder and explore the synergistic fire extinguishing effect between inert gas and powder,the fire extinguishing ability of ultra-fine KHCO₃dry powder,ultra-fine KH₂PO₄dry powder and ultra-fine ammonium phosphate ABC dry powder is studied by using the improved cup burner;The effects of gas-solid co fire suppression were studied by using ultra-fine KHCO₃dry powder and ultra-fine ammonium phosphate ABC dry powder as the research object,and the inert gas extinguishing agents of CO₂,N₂,He and Ar were selected.The results show that the fire extinguishing ability sequence is ultra-fine KHCO₃>ultra-fine ammonium phosphate ABC dry powder>ultra-fine KH₂PO₄;The results showed that the peak value of the coordination factors was 0.47,0.53,0.54 and 0.51,respectively,and the corresponding gas volume percentage was5.5%,5.9%,8.7%and 14.4%;The synergistic effect of KHCO₃powder and 4 inert gases is not obvious.The mechanism of collaborative fire extinguishing is analyzed,and the free radical recombination cycle is needed to determine the mechanism of collaborative fire extinguishing.