Synthesis of Biodiesel Using Alkali Ion Conductive Ceramic Membranes

Abstract

Methods and apparatus for synthesizing biodiesel using alkali alkoxide generated on-site using an electrochemical process are disclosed. The apparatus and methods are disclosed to converting alkali salts of glycerine into glycerine and thereby facilitate the separation of clean glycerine from biodiesel. These methods are enabled by the use of alkali ion conductive ceramic membranes in electrolytic cells.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of U.S. Provisional Patent Application No. 60 / 758,246 filed Jan. 11, 2006, which is incorporated by reference.FIELD OF THE INVENTION [0002] The present invention relates in general to the chemical synthesis of biodiesel using electrolytic cells that contain alkali ion conductive ceramic membranes. The invention incorporates the process of separating alkali ions from glycerine byproducts of biodiesel production. BACKGROUND OF THE INVENTION [0003] Biodiesel is an alternative fuel source to diesel, JP-8, and standard gasoline that is growing in popularity and market penetration in the United States and worldwide. Current methods of making biodiesel are outlined in the publication Biodiesel Production Technology, NREL, July 2004 (NREL / SR-510-36244). Biodiesel is defined as a fuel comprised of mono-alkyl esters of long chain fatty acids derived from triglycerides. A “mono-alkyl ester” is the product of the ...

AI Technical Summary

Benefits of technology

[0014] When an electric current is applied to the second electrolytic cell, hydrogen gas is oxidized at the second anode to form hydrogen ions. This reaction may be facilitated by the use of suitable catalyst compounds associated with the second anode. The hydrogen ions may then react with the alkali salts of glycerine to form clean glycerine. The influence of the electric potential causes free alkali ions to pass through the second alkali ion conductive ceramic membrane from the second anolyte compartment to the second catholyte compartment. Water is decomposed in the presence of alkali ions in the second catholyte compartment to form alkali hydroxide solution and hydrogen gas. Biodiesel and clean glycerine may be removed from the second anolyte compartment. They may be easily separated in a settling tank, if desired.

[0015] To increase the efficiency of the apparatus and method, hydrogen gas produced in the first catholyte compartment may be introduced into the second anolyte compartment. Similarly, hydrogen gas produced in the second catholyte compartment may be introduced into the second anolyte compartment.

Problems solved by technology

This process is cumbersome, complex, inefficient, and may elevate the cost of biodiesel.

Such processes have significant safety, sodium handling infrastructure, cost issues and / or often result in a product that is contaminated by mercury.

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