Publication – A computer-controlled biodiesel experiment

Proceedings to the 120th ASEE (American Society for Engineering Education) [Paper #7252]

• Dr. William Clark, Nicholas Medeiros, Donal Boyd, Jared Snell, Lucas Brutvan
• Chemical Engineering Department, Worcester Polytechnic Institute, Worcester, MA 01609

Biodiesel is fast becoming an increasingly popular alternative to petroleum based fuels. This paper describes a fully automated base-catalyzed transesterification process to produce biodiesel from vegetable oil. Transesterification converts the high viscosity oil into molecules which have viscosities that are more suitable for use as a fuel. The biphasic nature of the reaction requires efficient stirring to be performed in the Globe system to ensure a safe and reproducible process.

This synthesis was performed using a Globe Parallel System (replaced by Orb).

Abstract: Quantification of a pH change that was observed over the course of the transesterification reaction that converts vegetable oil to biodiesel may provide a simple method to monitor the reaction. Transesterification of canola oil at 6:1 methanol to oil ratio with

0.5 wt.% KOH as the catalyst was studied at 25, 35, and 45 C. Reaction conversion was correlated to pH measurements and the results were shown to be in agreement with an independent measure of conversion using an enzymatic assay for glycerol. Rate constants obtained from these measurements are consistent with those in the literature. The measured pH change appears to be related to dilution of OH ions as the oil is converted to products rather than to depletion of OH due to reaction.

This paper uses a Globe jacketed reactor (replaced by Orb).