Study On Suppression Of Ethylene Explosion By Gas Powder Two-phase Explosion Suppressant

As an extremely important chemical raw material,ethylene is prone to flammable and explosive accidents during its transportation and use due to its extremely low explosion limit（2.7%）.Explosives are particularly important to ensure the safe transportation and use of ethylene.This paper takes 6.5%ethylene-air mixture gas as the research object,and selects N₂,CO₂ as gas-phase detonation inhibitor,KH₂PO₄,KHCO₃ as powder detonation inhibitor and gas-powder composite two-phase detonation inhibitor.The detonation suppression performance and rules of detonation inhibitors were systematically studied.Combined with the chemical reaction kinetic model and the thermal decomposition characteristics of powder,the detonation inhibition mechanisms of three types of detonation inhibitors were revealed.Through the above research,the main work and conclusions are as follows:（1）N₂ and CO₂ were selected as gas-phase explosion suppressant based on their advantages of being clean and efficient,and their effects on ethylene explosion overpressure and flame propagation characteristics were systematically studied.The gas-phase explosion suppressant can completely suppress the explosion of ethylene,and the explosion suppression performance of CO₂ is better than that of N₂.In order to deeply study the difference of its explosion suppression performance,combined with the reaction mechanism of ethylene explosion,the CHEMKIN PRO software was used to build an explosion suppression model,and the chain reaction steps CO+OH（?）CO₂+H involved in CO₂ suppression of ethylene explosion were determined,revealing the effect of N₂ and CO₂.Explosion suppression mechanism.（2）The effect of powder detonation inhibitor on the overpressure and flame propagation characteristics of ethylene explosion was systematically studied.The powder explosion suppressant can suppress the ethylene explosion,and with the increase of the powder mass fraction,the ethylene explosion overpressure and the flame propagation speed decrease significantly.The lower powder detonation inhibitor has the best detonation inhibition performance.The anti-explosion properties of the two powders were compared and analyzed,and it was found that the anti-explosion performance of KHCO₃ was better than that of KH₂PO₄.In addition,combined with the thermal decomposition characteristics of the powder,the pyrolysis steps,pyrolysis products and heat absorption of the powder detonation inhibitor were determined,and then the mechanism of KH₂PO₄ and KHCO₃ inhibiting ethylene explosion was revealed based on their thermal decomposition characteristics.（3）The gas-powder two-phase detonation inhibitor was combined with the gas-powder detonation inhibitor.The effect of the gas-powder two-phase detonation inhibitor on the explosion overpressure and flame propagation characteristics of ethylene was systematically studied,and the gas-powder two-phase detonation inhibitor was obtained.Critical explosion suppression concentration and optimal compounding ratio of two-phase explosion suppressants.When 0.4 g/LKHCO₃ powder is compounded with 24%CO₂,the gas volume fraction and mass concentration of the powder required to completely suppress the explosion of ethylene are the smallest.Combining the anti-explosion mechanism of the gas-phase detonation inhibitor and the powder detonation inhibitor,by studying its coupling effect,that is,the use of the gas-phase detonation inhibitor prolongs the action time of the powder detonation inhibitor,which is more superior than the single-phase detonation inhibitor.The explosion-suppression performance revealed that the gas-powder two-phase explosion suppressant inhibited the explosion of ethylene.