正构醇对甲醇-汽油体系相稳定性的影响

THE EFFECT OF n-ALKANOL ON THE PHASE STABILITY OF METHANOL-GASOLINE SYSTEM

通过甲醇-汽油相稳定性实验,分别考察了一系列正构醇作助溶剂对甲醇-汽油体系相稳定性的影响;结合正构醇加量-相分离温度曲线线性回归方程,对其影响规律进行探讨。实验表明:在温度-25～40℃,C_3～C_8正构醇皆对M15(表示甲醇在甲醇-汽油体系中体积分数为15%)、M30、M35、M50、M65、M85甲醇-汽油体系有一定的助溶效果;正构醇结构以及甲醇比例对相稳定性都有显著影响,助溶效果随醇碳数的增加而增强,一般情况下,碳数大于5时才能达到最佳助溶效果;甲醇比例一定时,不同正构醇加量与其对应的体系相分离温度之间存在一定的线性关系,曲线的线性回归趋势线相关系数R^2值大都高于0.99;随着正构醇HLB值减小其对相同甲醇比例的甲醇-汽油体系相稳定作用增强。

The experiment on the phase stability was conducted to investigate the effects on the phase stability of methanol gasoline system when a series of n-alkanol were used as cosolvent. The effects of n-alkanol to the phase separation temperature have been analyzed by using linear regression method. From the results, it can be seen that the n-alkanol of C3 - C8 had good assistant dissolve effect to methanol-gasoline system of M15 （It indicates that the volume fraction of methanol in the methanol- gasoline system is 15%）, M30, M35, MS0, M65 and M85 within the experimental temperature range -25 - 40 ℃. Both the structure of n-alkanol and methanol ratio had a significant impact on the phase stability. The codissolve effect was greatly enhanced with the increasing of carbon numbers in the al-cohol, and the best codissolve performance was obtained when carbon number was more than five. The relationship between the amount of n-alkanol and phase separation temperature was linear when the ratio of methanol to gasoline is certain. R2, the curve correlation coefficient, is usually higher than 0.99. The blends phase stability was enhanced with the decrease of HLB value of n-alkanol.