Research On Inhibition Of Methane/Air Explosion By Heptafluoropropane Under High Explosive Ignition

The prevention and control of natural gas explosion accidents is the primary task to ensure the safe production of coal mines and industries.In order to solve the explosion problem in the process of natural gas transportation,This paper has carried out relevant research on the technology of pipeline gas explosion prevention and control,and accumulated experimental basis for further putting forward effective measures for gas explosion prevention and control.Based on 9.5% methane-air premixed gas,a test system of explosion characteristics of horizontal pipeline with a ratio of length to diameter L/D=108 was established.The effect of heptafluoropropane on explosion flame was studied.The range and amount of heptafluoropropane spraying were adjusted by setting up 6 spray holes.Using high-speed photography system and pressure sensor to capture the characteristic parameters of explosion flame propagation,the influence of heptafluoropropane spraying range and amount on methane explosion flame propagation process and explosion pressure under strong ignition was carried out.,mainly including the following contents:(1)A set of anti-explosion agent spraying system for horizontal pipe was built.According to the structure characteristics of circular explosion flame propagation test pipe with threaded holes,the purpose of controlling the spraying range and amount of heptafluoropropane was realized by combining high precision Alicat mass flowmeter with high pressure gas tank and valve switch.;(2)The effect of different amount of heptafluoropropane spraying on explosion pressure and explosion flame propagation of methane-air premixed gas in experimental pipeline was analyzed under the condition 2.32 m.The conclusion was reached that heptafluoropropane with low amount of spraying could accelerate explosion flame propagation,and the minimum amount of heptafluoropropane spraying which could block the explosion flame propagation of 9.5% methane-air premixed gas was determined to be 300 mL.;(3)By reducing the number of openings for blast suppressant spraying,under the conditions of blast suppressant spraying range of 1.72 m and 1.12 m,the effects of different heptafluoropropane spraying amount on the explosion pressure and explosion flame propagation of methane-air premixed gas were studied.It was concluded that the minimum spraying amount of heptafluoropropane to block 9.5% methane-air premixed gas explosion flame propagation was 300 m L and 660 m L respectively;(4)The influence of heptafluoropropane spraying range and spraying quantity on methane explosion was analyzed synthetically,and the order of the effect of heptafluoropropane spraying range on methane-air explosion suppression was obtained.The minimum spraying quantity of heptafluoropropane spraying range of 1.12m、1.72 m and 2.32 m was 660 m L、300m L and 300 m L respectively.and some suggestions on the prevention measures of gas pipeline explosion and the matters needing attention in determining the dosage of heptafluoropropane in explosion suppression device were put forward.