Experimental And Kinetic Study Of Benzene And N-propylbenzene Oxidation At Elevated Pressure

Fossil fuels have always played a very important role in the history of mankind.With the progress of human society and the development of technology,fossil fuels have been extracted in large quantities.The utilization of large amounts of fossil fuels is accompanied by serious environmental pollution.The pollutants mainly refer to polycyclic aromatic hydrocarbons(PAHs)and carbon soot,etc.In fossil fuels,aromatic hydrocarbons are important constituents and also precursors for the formation of pollutants.Therefore,the study of aromatic hydrocarbon components in fuels contributes to the understanding of the pollutant formation mechanism.In this paper,monocyclic aromatic benzene(A1)and monobranched alkylbenzene n-propylbenzene(A1C3H7)with simple structures were selected for high-pressure oxidation experiments,which were used to simulate the oxidation behavior of aromatic hydrocarbons in real fuels.This high-pressure oxidation study helps to reduce pollutant emissions and improve the efficiency of fossil fuel utilization.Literature research shows that a large number of theoretical experimental studies have been carried out on A1 and A1C3H7,mainly focusing on oxidation and pyrolysis experiments at atmospheric pressure.Under high pressure conditions,studies have focused on the measurement of macroscopic parameters,such as ignition delay time and laminar flame velocity.In this paper,oxidation experiments were performed in a high-pressure jet stirred reactor(HP-JSR)for 12 atm and 24 atm,respectively.The products after the reaction were analyzed quantitatively and qualitatively using two gas chromatographs(GC)and a mass spectrometry chromatograph(GC-MS).Chemkin-pro software was used to construct kinetic models and simulate the experimental results.The main part of this work is divided into two modules.The first module is a high-pressure oxidation experiment of Ai done in HP-JSR at a reaction temperature range of 880-1010 K and a pressure of 12 atm.A total of 18 components were detected by two GCs and one GC-MS.Compared with the previous work,the oxygenated polycyclic aromatic hydrocarbons(OPAHs)components benzofuran(C8H6O)and dibenzofuran(DIBZFUR)were newly detected.Based on the experimental results,a high-pressure oxidation mechanism of A1 containing 272 components and 1716 reactions was constructed.The mechanism model was able to simulate the experimental results well.The general applicability of the model was verified by simulating the experimental data of ignition delay time and flame propagation velocity as well as different pressures.The rate of production analysis(ROP)and sensitivity analysis showed that the hydrogen extraction reaction A1+OH=A1-+H2O was the strongest reaction to promote A1 consumption;A1OH+O2=A1O+HO2 was the strongest reaction to inhibit A1 consumption.The second module was also performed in the HP-JSR,where highpressure oxidation experiments of A1C3H7 were done at a reaction temperature range of 640-820 K,pressure of 24 atm.A total of 18 components were detected by two GCs and one GC-MS.Compared with the experimental results of A1,the oxidation products of A1C3H7 were more abundant in aromatic components and less in light hydrocarbon components.Based on the experimental results,a high-pressure oxidation model of A1C3H7 was constructed for 340 components with 2069 reactions.The most obvious reaction that promoted the consumption of A1C3H7 by ROP and sensitivity analysis was the hydrogen extraction reaction A1C3H7+OH=A1CHCH2CH3+H2O.the most obvious reaction that inhibited the consumption of A1C3H7 was A1OH+O2=A1O+HO2.In summary,the present work studies aromatic fractions based on fuels.Two structurally specific aromatic fractions,monocyclic aromatic A1 and monobranched aromatic A1C3H7,were selected for the study in the benzene article.High-pressure oxidation experiments at 12 atm and 24 atm were carried out in HP-JSR,respectively.The oxidation behavior of the aromatic components in the fuel was investigated.The research in this paper contributes to an in-depth understanding of the reaction kinetics of aromatic oxidation at high pressure,which is important for controlling the pollutant emissions from fossil fuels.