Yield Characteristics of Biodiesel Produced from Chicken Fat-Tall Oil Blended Feedstocks

The primary objective of this study was to investigate the conversion of chicken fat and tall oil, both individually and in a blend, into biodiesel. The conventional base-catalyzed method of biodiesel production has shown to be inappropriate for the conversion of high free fatty acid-containing feedstocks such as tall oil, due to the undesired saponification reaction that takes place. Likewise, the acid-catalyzed method of biodiesel production has been shown to be inappropriate for the conversion of triglyceride-containing feedstocks, such as chicken fat, due to the long reaction times and large excess of methanol required. Therefore, an alternate reaction pathway was investigated for these two very different feedstocks. Supercritical methanol treatment, which requires no separate catalyst, was the method chosen. Following the development of proper protocol, both chicken fat and tall oil fatty acids were reacted in supercritical methanol to produce biodiesel under a matrix of temperatures and methanol to feedstock ratios. Results indicate that the chicken fat and tall oil fatty acids can be converted successfully in a single step with yields in excess of 89% (out of 91% max) and 94% respectively. The optimum temperature and excess methanol was determined, and the results suggest the use of a two step process involving the initial hydrolysis of triglyceride-containing feeds followed by the supercritical esterification of the resulting/existing free fatty acids. The results of one such test proved to be satisfactory, and are reported herein. Furthermore, crude tall oil was also tested in the system to investigate its viability as a biodiesel feedstock with limited success. Cold flow properties, such as viscosity and cloud point, are reported for the resultant fuels. The viscosities of all of the fuels exceeded the ASTM D6751 acceptable specifications for biodiesel; therefore blending with other biodiesel fuels such as methyl soyate would be required for widespread use of the fuels produced under the conditions reported herein as commercial biodiesel.

• Supplemental Notes:
  • This research was funded by the U.S. Department of Transportation, University Transportation Centers Program.
• Corporate Authors:

  Mack-Blackwell Transportation Center

  University of Arkansas, 4190 Bell Engineering Center
  Fayetteville, AR  United States  72701

  Research and Special Programs Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Babcock, R E
  • Clausen, E C
  • Popp, Michael
  • Schulte, W Brent
• Publication Date: 2008-1

Language

• English

Media Info

• Media Type: Print
• Edition: Final Report
• Features: Figures; References; Tables;
• Pagination: 47p

Subject/Index Terms

• TRT Terms: Alternate fuels; Biodiesel fuels; Clean fuels; Methanol; Oils; Yield strength
• Uncontrolled Terms: Feedstocks; Poultry
• Subject Areas: Energy; Environment; Highways; I15: Environment;

Filing Info

• Accession Number: 01090160
• Record Type: Publication
• Report/Paper Numbers: MBTC 2092
• Files: UTC, TRIS, USDOT
• Created Date: Mar 21 2008 8:13AM