050048: Process for Production of Higher Yield Low-Emission Biodiesel

Biodiesel is rapidly gaining market momentum as the next major biofuel for energy sustainability. Factors such as the recent spike in oil prices, the increasing environmental awareness of U.S. consumers and recent tax incentives have all spurred interest and rapid growth in biodiesel technologies in the U.S. However, according to the U.S. Department of Energy, the continued growth of the biofuels industry and the long-term market potential for biofuels depends upon the resolution of critical issues that influence the supply of and demand for biofuels. For each of the major biofuels-corn-based ethanol, cellulosic ethanol, and biodiesel-resolution of technical, economic, and regulatory issues remains critical to further development of biofuels. Improved processes that produce biofuel at lower costs, higher yields and lower emissions are needed in order to address these challenges.


Invention is a continuous distillation process for the preparation of a composition that is useful as a fuel oil. Vegetable oil is partially reacted with ethanol or methanol in a fixed bed reactor that is aided by a solid acid catalyst. The resulting stream contains a mixture of biodiesel, unreacted oil, glycerol and alcohol that is fed to a reactive distillation column. During this process the alcohol is further reacted (with triglycerides) in order to make more fatty acid esters through transesterification. At the same time added acetaldehyde reacts with the glycerol to form glycerol acetal or HMD (4-hydroxymethyl-2methyl-1,3-dixolane). The HMD is retained in the biodiesel and serves as an oxygenate which may improve combustion properties of the biodiesel thereby reducing particulate emissions.


  • Enables direct production: This is a direct process for the formation of the glycerol acetals in fuel oil composition, bypassing the need for a separation step to remove glycerol.
  • Increased reliability: The process reliably and economically produces the biologically derived fatty acid esters.
  • Reduced emissions: HMD present in the biodiesel could improve combustion properties and reduce particulate emissions.
  • Improved yield: The process indicates improved biodiesel yield.


The technology could be used to produce a fuel oil or a diesel fuel.

IP Protection Status

US 7,321,052 B2 (issued January 22, 2008)
Patent Information:

For Information, Contact:

Thomas Herlache
Assistant Director
Michigan State University - Test