Study On Mechanism Of Benzyl Alcohol At Low Temperature Combustion

As a typical raw material of second generation biomass fuels,lignin can be decomposed into small molecule fuels via chemical method,such as benzyl alcohol.As a biodiesel,benzyl alcohol has many advantages,such as good discharge performance and low fuel consumption.The development of a detailed mechanism that accurately describes the low temperature combustion process of benzyl alcohol is essential for microscopic understanding of the combustion process of benzyl alcohol.The jet-stirred reactor is a reactor commonly used to study combustion process.Based on the design principles of jet-stirred reactor,this work demonstrates that the jetstirred reactor used in this work can uniformly mix the gas mixture at the internal and the outlet of the reactor.In this work,the jet-stirred reactor was used in combination with two combustion diagnostic instruments,i.e.a gas chromatograph and a GC / MS.The low temperature atmospheric oxidation experiment of benzyl alcohol was conducted at an equivalence ratio of 0.4 and 2.0 in the temperature range of 700-1100 K for the first time.The reactants,intermediates and products were identified and quantified by online GC and GC/MS analysis.Mole fraction data of 19 species,including fuel,intermediates and main products,were obtained.Benzaldehyde and phenol are the main oxygenated intermediates.The concentration of intermediates containing oxygen have higher peak value at the equivalent ratio of 0.4,while the concentration of light hydrocarbon and aromatic intermediates have higher peak value at the equivalent ratio of 2.0.Simultaneously,based on the experimental data obtained in this work,a detailed mechanism of low temperature oxidation of benzyl alcohol is proposed for the first time,including 296 species and 1850 elementary reactions.The mechanism is simulated by Chemkin Pro software.The simulation results of this mechanism can reproduce the experimental data well,which shows the rationality of the mechanism.In this work a rate-of-product analysis and a sensitivity analysis are conducted.The rate-of-product analysis shows the generation pathway of the main intermediates and the sensitivity analysis lists reactions which show great promotive or inhibitory effect on the comsuption of benzyl alcohol.The rate-of-product analysis shows that the H-abstraction reactions of benzyl alcohol accuring at the α position are the main consumption channel and the sensitivity analysis shows that the reaction of free radicals to produce benzaldehyde produced by H-abstration reactions of benzyl alcohol occuring at α position has the greatest promotive effect on the consumption of benzyl alcohol.