Translated Abstract
ABSTRACT
The fuel blends of methanol and gasoline are the most potential alternative fuel to be applied, while the fuel vapor pressure and distillation processes changes greatly due to the feature of azeotropy, causing negative effects on fuel storage, transportation, and the engine performance. Therefore, theoretical and experimental studies on evaporability of methanol /gasoline blends were carried out in this thesis. By means of research on vapor-liquid equilibrium of methanol /gasoline blends, the mechanism of the fuel blends’evaporability was revealed, and the vapor pressure formula of the fuel blends was established. According to the evaluation criterion of evaporability, vapor pressure and distillation test experiments of methanol /gasoline blends and base gasoline were carried out, and the azeotropic ingredients were detected with GC-MS for the distillation of methanol /gasoline blends. The major work and conclusions about this study are as follows:
1. The intermolecular force in gasoline is dispersion force, while it is hydrogen bonding force in methanol. Adding a certain volume of methanol in gasoline, the intermolecular forces were destructed due to the tremendous differences and unable to form large mutual attraction. The blends show a strong positive deviation, methanol and some components of gasoline generate low boiling point azeotropes.
2. The vapor pressure of methanol /gasoline blends rised rapidly. When the methanol concentration reaches 10%, its vapor pressure reaches the maximum. Then, with the increase of the volume fraction of methanol, methanol vapor pressure began to take a leading role. Due to the low vapor pressure of methanol, when the methanol concentration is over 80%, the blends’ vapor pressure becomes gradually lower than that of gasoline. The increased value of the blends’ vapor pressure at high temperature (40℃) is much larger than that at low temperature (0℃). Therefore the occurrence of vapor lock should be avoided when methanol /gasoline blends were applied to improve cold start performance.
3. The distillation temperature of methanol /gasoline blends is generally lower than that of pure gasoline. T10, 10% distillation temperature reduces to some extent for methanol /gasoline blends, T50, 50% distillation temperature of methanol /gasoline blends with more than 15% methanol volume fraction reduces remarkably. But all methanol /gasoline blends have almost the same 90% distillation temperature as pure gasoline.
4. Among all base gasolines, the reformulated gasoline and aromatization gasoline has a lower vapor pressure. The reformulated gasoline and aromatization gasoline mixed as 8:2 ratio has the lowest vapor pressure by adding certain volume fraction of methanol, showing good performance to prevent the occurrence of vapor lock. Heavy gasoline and etherification gasoline has the highest distillation temperature by adding certain volume fraction of methanol, appropriately increasing the ratio ot the two base gasoline can make a positive effect to prevent the occurrence of vapor lock.
5. The results of ingredient detecting experiment with GC-MS of methanol /gasoline blends’distillation show that there are five ingredients whose content change tremendously at different temperature. This five ingredients can be determined to be the azeotropes with methanol. They are: 2-methyl-butane, pentane, 2-methyl-2-butene, hexane, toluene. They have different boiling points, indicating that methanol can be azeotroped with light and heavy components in gasoline.
KEY WORDS: Methanol /gasoline Vapor pressure Distillation Azeotropy
TYPE OF THESIS: Applied Fundamentals
Translated Keyword
[Methanol /gasolineVapor pressureDistillationAzeotropy]
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