Aplikasi Response Surface Method untuk Optimasi Kondisi Proses Produksi Biodiesel Jarak Pagar Melalui Transesterifikasi In Situ

Abstract

A conventional jatropha seeds biodiesel production is conducted through many stages and long time process. It requires high production cost where 70% of production cost is used for extraction and purification. In situ transesterification can be an alternative solution for conventional biodiesel production problems. This study aims to optimize the process conditions of the jatropha seeds biodiesel production through in situ transesterification using RSM, and to determine the influence of the process conditions on the yield and quality of the biodiesel. The variables of process conditions optimized were the ratio of hexane to total solvent (X1), reaction temperature (X2), reaction time (X3), and agitation speed (X4), where the response was yield, viscosity, acid value, saponification value, and ester value. The optimum process conditions for biodiesel yield were obtained on X1= 0, X2= 57.9 °C, X3= 5.4 hours, and X4= 206.5 rpm. The optimum process conditions for biodiesel quality (viscosity; acid value; saponification value; ester value) were obtained on X1= 0.33, X2= 55.8 °C, X3= 3.2-5.2 h, and X4= 300-600 rpm. Polynomial model for biodiesel yield was first order polynomial model or linier and for biodiesel quality was third order polynomial model or cubic. The ratio of hexane to total solvent (X1) affected significantly biodiesel yield and quality. The optimum process conditions with multi response was obtained on X1= 0.06, X2= 53.3 °C, X3= 6 h, and X4= 392.4 rpm, with y1= 81.3%, y2= 0.14 mg KOH/g, and y3= 3.2 cSt. The validation on this optimum process conditions resulted y1= 77.5%, y2= 0.16 mg KOH/g, and y3= 3.6 cSt. The difference between the results of validation and model prediction was less than 5%, the model was thus good.