Analisis Kinetika Reaksi Transesterifikasi pada Produksi Biodiesel secara Katalitik dengan Static Mixing Reactor

Abstract

Biodiesel merupakan bahan bakar diesel yang diproduksi dari ester asam lemak atau minyak nabati yang merupakan sumber terbarukan (renewable). Proses produksi biodiesel dibagi ke dalam dua proses, yaitu secara katalitik dan non-katalitik. Metode non-katalitik masih memiliki beberapa kelemahan, yaitu nilai rasio energi yang masih kecil dan laju reaksi yang masih lambat. Sehingga, proses secara katalitik masih menjadi pilihan utama dalam proses produksi biodiesel untuk skala besar. Proses produksi secara katalitik membutuhkan bantuan katalis untuk mempercepat terjadinya reaksi trigliserida dan metanol dengan cara menurunkan energi aktivasi. Disamping itu, metode katalitik memerlukan pengadukan yang kuat (rigorous stirring) karena sifat TG dan metanol yang sulit untuk saling tercampur (immiscible). Dan untuk mengatasi masalah pengadukan tersebut, pada penelitian ini digunakan static mixer.

Catalytic process of biodiesel production requires rigorous mixing and a certain amount of catalyst itself in order to obtain the proper result of the process. Hipotetically, a good mixing can reduce the amount of required catalyst for a certain results. In this study, a static mixing reactor with KOH as catalyst was used to produce biodiesel. The objective of the study were (1) to evaluate the affect of decreassing the amount of KOH required as catalyst for the biodiesel production in the static mixing reactor (2) to study the kinetics of the reaction. The result showed that the percentage of catalyst greatly affected the reaction conversion, yield and kinetics of the transesterification reaction at the beginning of the reaction and declined afterward, because its ability nearly reached its maximum capacity. The model of reaction order that most appropriate to describe the condition of transesterification in this study was a pseudo third-order model. The activation energy was 71.83 kJ mol-1, and the influence of static mixers in the reactor was indicated by the value of the collision frequency factor (1.95 x 108 min-1). In other words, the presence of static mixer has a significant influence in accelerating the reaction.