Group 9: Design of a Continuous Washing Process for Biodiesel

Welcome to the group webpage describing our Senior project for Chemical Engineering Lab (CHE 415) at Oregon State University in Corvallis, Oregon.

Group members:

• Gabe Montero monterog@onid.orst.edu
• Becky Solano solanor@onid.orst.edu
• Trevor Binney binneyt@onid.orst.edu

Photos from left to right: Gabe, Becky, Trevor

Project Objectives:

The purpose of this project is to develop an efficient, effective continuous washing method to remove impurities of soap, sodium hydroxide, and methanol from biodiesel.

The Problem:

Biodiesel is created by separating methyl esters from a glycerol backbone that holds together a fat molecule. This is induced by introducing methanol and sodium hydroxide into a vat of triglycerides. After the reaction occurs, some of the methanol and sodium hydroxide is left dissolved in the biodiesel, as well as some soap that formed as a byproduct. These contaminants can be deleterious to the performance of your diesel engine.

Washing is a process by which water is used to remove these impurities from biodiesel. Traditionally this has been accomplished in a batch process, which involves a large labor and time investment. Water is added to the biodiesel, then the mixture is aggitated usually by bubbling air through both liquids. After adequate mixing, up to 3 weeks of settling time (depending on how emulsified the two phases become and ambient temperature) is required to allow the two phases to separate out naturally. If low quality fuel is strongly aggitated, a stable emulsion can form that will never separate.

The Solution:

With a continuous process we hope to be able to reduce labor and time expenditures involved in purifying biodiesel. This is a classical mass transfer problem involving two immiscible phases with low contaminant concentrations. We have at our disposal three types of continuous contact liquid-liquid extractors; a box-type mixer settler, a packed column, and a centrifugal extractor.

Click Here for an Image of a Column Extractor Schematic

Click Here for an Image of a Box-Type Mixer Settler Schematic

Click Here for an Image of a Centrifugal Extractor Schematic

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