乙醇／汽油发动机排气温度下乙醇氧化生成醛的特性

摘要

为了研究乙醇／汽油发动机排气温度下乙醇氧化产生甲醛和乙醛的特性,设计并搭建用于乙醇氧化的流反应器,借助汽油机排气温度对流反应器加热,配制乙醇标准气,研究了乙醇／汽油发动机排气温度下流反应器中乙醇的氧化特性.结果表明:利用乙醇标准气在流反应器中氧化得到了乙醇氧化、甲醛和乙醛生成与氧化的特性,研究了排气温度和流速对乙醇氧化、甲醛和乙醛生成及氧化的影响规律.乙醇质量分数随温度升高而降低,甲醛和乙醛质量分数随温度升高呈先增加后减小趋势,并拟合得出甲醛和乙醛生成与氧化的临界温度,临界温度处甲醛和乙醛质量分数最高,临界温度时乙醛最高质量分数约为甲醛质量分数的16倍.%An ethanol oxidation test bench,which is mainly composed of a flow reactor,was designed and built.A stainless steel pipe was installed into a gasoline engine exhaust pipe,through which the sample gas flows into the reactor with the typical exhaust temperature environment.Ethanol oxidation characteristics were investigated in the flow reactor under the real exhaust temperature environment.The experimental results show that the ethanol initial oxidation temperature and aldehydes characteristics are obtained by ethanol oxidation in the flow reactor.Then,the effects of exhaust gas temperature and flow rate on ethanol oxidation,aldehydes formation and oxidation were investigated.It is found that ethanol mass fraction decreases with the increase of the temperature.However,aldehydes increase at first and then decrease with the increase of temperature.In addition,the critical temperature of the formation and oxidation of aldehydes is fitted from experiment data.The highest acetaldehyde mass fraction is found to be about 15 times higher than the formaldehyde mass fraction at the critical temperature.