| Summary: | 碩士 === 國立臺灣大學 === 化學工程學研究所 === 103 === The separation process accounts for over 50% of the operating cost in chemical engineering industry based on the literature survey. A pervaporation process with existed distillation tower would significantly reduce energy consumption. We designed a system of pervaporation apparatus and used graphene oxide/chitosan membrane. The esterification of ethanol and acetic acid with pervaporation was performed, and the experiment results showed that the conversion is enhanced due to continuous removal of the water from the solution. The overall reaction favors the product side as described by Le Chatelier principle.
We investigated various kinetic parameters included reaction temperature, loadings of solid acid catalyst and initial molar ratio of ethanol to acid. The results showed higher temperature and more catalyst loadings had positive influence. The conversion increased 8% under the optimal conditions at 70oC, 2.25wt% catalyst and initial ratio of ethanol to acetic acid =2:1 .
In addition, we tried the combination of pervaporation and pre-esterification process of biodiesel production. There existed 2 to 7wt% of free fatty acid (FFA) in the feedstock. FFA would react with base catalyst to produce soap and reduce the yield of biodiesel. Generally, the pre-esterification was applied before transesterification step to reduce the amount of FFA lower than 0.5wt%. We integrated pervaporation with pre-esterification together to study the enhancement of eliminating FFA. We chose palmitic acid as a representative of FFA. The conversion was enhanced by 20% under the conditions, methanol: palmitic acid=20:1 and 10wt% of solid acid catalyst at 50oC.
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