Mechanism Of Laminar Premixed Combustion Of Biodiesel And Its Simplification

An oxidation process of biodiesel includes oxidative rancidity and rapid oxidation(combustion)process at room temperature.Because biodiesel contains unsaturated fatty acid methyl esters,it is easily oxidized at room temperature,which affects the storage and use of biodiesel.The rapid oxidation process is the main method of using biodiesel.Both oxidation processes are closely related to the use of biodiesel.In this paper,the effects of slow oxidation on the combustion and atomization characteristics of biodiesel were studied by measuring the density and heat value before and after the oxidation reaction of biodiesel occurred.The results show that slow oxidation has an adverse effect on the atomization and combustion of biodiesel.In order to prevent the slow oxidation of biodiesel,three ionic liquid antioxidants were designed and synthesized in one step,and the anti-oxidant effect of ionic liquids was determined by Lanchima method.The anti-oxidation effect of biodiesel,especially 1-styreneimidazole gallic acid ionic liquid,when the addition amount is 0.2 ‰,the oxidation induction period of biodiesel exceeds the national standard 6h.At the same time,some ionic liquids have better oil solubility and corrosion characteristics of copper flakes.Among them,1-ethylimidazole gallic acid ionic liquid has the strongest oil solubility.The frontier molecular orbital theory and natural bond orbital theory were used to analyze the antioxidant mechanism of various ionic liquids.The results show that-OH groups on the benzene rings of the three ionic liquids have overlapping reactivity and molecular weight density,and-OH groups can preferentially react with free radicals to protect biodiesel from being oxidized by free radicals.The density functional theory was used to calculate the biodiesel five.The results showed that among the five kinds of fruit starches,the CC single bond dissociation energy at the fifth position in methyl linolenate was the lowest,and the C = C double bond at the nine position of methyl linolenate The bond dissociation energy is the highest,which indicates that when five kinds of fatty acids are dissociated,methyl linolenate will react first,and the CC single bond at the fifth position will decompose to form alkyl and alkyl ester.The critical temperatures of five fatty acid methyl esters calculated by the group contribution method.And critical pressure,the LJ parameters of the five fatty acid methyl esters calculated by the fitting formula.The parameters of collision integrals and boundary diffusion coefficients of five fatty acid methyl esters were calculated by LJ parameters.These parameters together constitute the transport characteristics in the combustion process.Based on the analysis of fuel properties,the simplification of the laminar premixed combustion mechanism of biodiesel was studied using methyl butyrate.The reaction path analysis method and sensitivity analysis method were used to simplify the chemical reaction kinetics of methyl butyrate.Combined with the initial reaction path of the rapid oxidation reaction of biodiesel,the rapid oxidation reaction path of biodiesel is generated.