Study On The Fire Extinguishing Effect And Chemical Kinetic Fire Extinguishing Mechanism Of Perfluorohexanone And Perfluorotrietriamine

Halon fire extinguishing agents have been banned from production and use because they seriously damage the ozone layer.The development of alternative halon fire extinguishing agents has become an important research direction in the field of fire protection.Perfluorohexanone has a good fire extinguishing effect and low ozone depletion potential.However,researchers found that C₆F₁₂O has a combustion enhancement phenomenon at its low concentrations.The defect may bring some harms in the process of firefighting,and may limit its application in some scenario.In order to suppress the combustion enhancement effect of C6F12O,this article adopts the method of mixed gas and introduces perfluorotriethylamine??C₂F₅?₃N?as a cooperative fire extinguishing agent with C₆F₁₂O.Firstly,the cupburner experiment was used to obtain the flame height and flame width at different concentrations of C₆F₁₂O,and the Minimum extinguishing concentration?MEC?of C₆F₁₂O was obtained as well.Pyrolysis experimental equipment was used to study the pyrolysis products of perfluorohexanone and perfluorotriethylamine at different temperatures.For the perfluorotriethylamine fire extinguishing agent,Gaussian software was used to calculate the pyrolysis reaction and the reaction of its products with H and OH radicals.?1?The combustion enhancement phenomenon of perfluorohexanone occurs at low concentration;when the concentration of perfluorohexanone is about 3%,the combustion enhancement phenomenon is most significant.After the addition of perfluorotriethylamine,the combustion enhancement of perfluorohexanone at low concentrations can be effectively suppressed;the critical fire extinguishing concentration of perfluorotriethylamine is about 4.86%.In the mixed fire extinguishing gas of perfluorohexanone and perfluorotriethylamine,after the volume fraction of perfluorotriethylamine exceeds 10%,perfluorohexanone and perfluorotriethylamine have a better synergistic fire extinguishing effect.?2?The retention time was 10s,the initial pyrolysis temperature of perfluorohexanone was 500°C,and the pyrolysis was complete at 700°C.Perfluorohexanone pyrolysis products are mainly perfluoroisopentane,C₃F₈,C₄F₁₀and so on.When the pyrolysis temperature is 500-650°C,the perfluoroisopentane content is the highest.When the pyrolysis temperature is 650-700°C,the volume fraction decreases continuously due to the further decomposition of perfluoroisopentane,and the C4F10 content is the highest.The retention residence time was 10s,the initial pyrolysis temperature of perfluorotriethylamine was 600°C,and the pyrolysis was completely pyrolyzed at 750°C.The pyrolysis products of perfluorotriethylamine are mainly C₄F₉N,C₃F₇N,hexafluoroethane,and octafluoropropane.Increasing the residence time to 20s,the volume fractions of C₄F₉N and C₃F₇N decreased,and the volume fraction of C₃F₈ increased greatly.?3?There are 4 reaction pathways in the pyrolysis of perfluorotriethylamine,and the cis-C4F9N and trans-C₄F₉N products are formed through the 2 reaction pathways with potential barrier.In the reaction system of C₄F₉N and H radical,the energy barrier crossed by the addition reaction is the lowest,and it is the most important reaction path and generates products Mb1 and Mb2.During the subsequent reaction of Mb1 and Mb2,?-C-C bond breaking reaction is the main reaction path.In the reaction system of C4F9N and OH radicals,the main reaction path is the formation of Ma1 by the addition of OH radicals to the carbon atoms in C=N.And in the subsequent reactions,?-C-C bond-breaking reaction and the isomerization reaction of H atom become the main reaction path.