固體觸媒進行酯化/轉酯化反應生產生質柴油

Abstract

生質柴油為一種替代石油之能源，其合成方法主要為轉酯化反應。本研究使用固體觸媒催化酯化/轉酯化反應解決進料油中自由脂肪酸之問題。 第一種方式：利用固體酸觸媒，同時催化酯化/轉酯化反應。使用市售豬油作為反應物，以SZA (Sulfated Zirconia Alumina)固體酸觸媒進行催化，針對觸媒含量、醇油比以及反應溫度等反應參數進行探討，並實際選用含自由脂肪酸之廢食用油進行反應。實驗結果顯示，在反應條件：醇油比為12比1，觸媒含量為1.0wt%，反應溫度為150oC，反應時間2hr下，反應產率約可達到80%；另外，由廢食用油之反應產率可看出，此觸媒催化效率不受原料油影響，故可選用品質較差之廢食用油作為原料油，以達到降低成本目的。 第二種方式：第二種方式為兩步驟反應。在較溫和的反應溫度60oC下，先利用SZA (Sulfated Zirconia Alumina)固體酸觸媒催化酯化反應，轉化油品中自由脂肪酸成為酯類，再以二甘油化鈣Ca(C3H7O3)2固體鹼觸媒催化轉酯化反應，分別以添加5wt%、20wt%棕櫚酸之大豆油(模擬含自由脂肪酸的油脂)為進料油。實驗結果顯示，第一步驟酯化反應確實有其必要性，且經過兩步驟反應後，整體產率約為80%。

Biodiesel is an alternative fuel for traditional fossil fuel. It can be produced by transesterification from triglyceride. In this study, we use solid catalysts to catalyze esterification and transesterification in order to solve the problems of free fatty acid (FFA) in the feedstock oil. The first method：Both esterification and transesterification were catalyzed simultaneously by solid acid catalyst. In experiment, we used commercial lard as feedstock oil, and SZA (Sulfated Zirconia Alumina) solid acid catalyst to catalyze both reactions. We studied different reaction parameters, the catalyst amount, the methanol/oil molar ratio, and reaction temperature. We also chose waste cooking oils (WCO) which contained FFA as feedstock oil. Under methanol/oil molar ratio 12/1, catalyst amount 1wt%, reaction temperature 150oC, and reaction time 2hr, the biodiesel yield reached 80%. Moreover, the biodiesel yield of WCO showed that different feedstock oils did not influence the efficiency of catalyst. So we could use the low quality WCO as the feedstock oil to decrease cost of oil. The second method：The second method was two sequence reactions. Under mild reaction temperature 60oC, use SZA solid acid catalyst to catalyze esterification first. The objective was to convert FFA into ester. Then used calcium diglyceroxide Ca(C3H7O3)2 solid base catalyst to catalyze transesterification. We added 5wt% and 20wt% palmitic acid into soybean oil to simulate the feedstock oil which contained FFA. The research result showed that it was necessary to esterify FFA in oil in the first step, and the overall yield was 80% after this two sequence reactions.