Biodiesel is a renewable, biodegradable, environmentally benign fuel for use in the diesel engines. It can be produced from renewable sources such as vegetable oils or animal fats. Although this fuel has gained worldwide recognition for many years, it is not being widely commercialized mainly because it is more expensive than petroleum diesel. A cheaper feedstock, such as fryer grease, may be used to improve the economics of biodiesel. <p>Methanol is the most common alcohol used in the transesterification process due to its low cost. However, recently, ethanol has been promoted as an alcohol for use in transesterification since it can be produced from renewable resources such as switchgrass, corn and wood, thereby reducing the dependency on petroleum sources (Pimentel and Patzek, 2005). A mixture of methanol and ethanol is hypothesized to take the advantages of both methanol and ethanol. The present work is focused on the production of biodiesel from fryer grease via transesterification with various mixtures of methanol and ethanol. Also, the kinetics of transesterification from fryer grease was studied. <p> Since fryer grease contains a high concentration of free fatty acids (FFA) (5.6 wt. %) and water (7.3 wt. %), a two-step acid/alkaline transesterification process was used to produce the esters. Sulfuric acid and potassium hydroxide were used as acid and alkaline catalysts, respectively. The methanol to ethanol molar ratio was varied from 3:3 to 5:1, whereas alcohol to oil molar ratio was maintained at 6:1. After the fryer grease was transesterified, all esters met ASTM standard D-6751. The viscosity of these esters ranged from 4.7 to 5.9 mm2/s. The heating value of the esters was approximately 10% less than that of petroleum diesel. The cloud point and pour point were in the range of 1 to -1 oC and -3 to -6 oC, respectively. When the mixed alcohol was used ethyl esters were also formed at a lower concentration along with methyl esters. The dominant fatty acid in fryer grease esters was found to be oleic acid. The lubricity of kerosene fuel was improved by as much as 33 % through the addition of these esters at rates as low as 1 %. <p>For the kinetic study of alkali-catalyzed transesterification of fryer grease, the alcohol to oil molar ratio, the reaction temperature, and the catalyst loading were varied as 6:1, 9:1, 12:1; 30, 40, 50 oC; and 0.5, 1.0, 1.5 %, respectively. The ester concentration was found to rise with an increase in the catalyst loading or the reaction temperature and with a decrease in the alcohol to oil molar ratio. The overall forward and backward reaction orders were assumed to follow first and second order kinetics, respectively. The kinetic parameters were calculated using MATLAB. The conversion of triglyceride to diglyceride was found to be the rate determining step (RDS) of the overall reaction, with an activation energy of 36.9 kJ/mol.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:SSU.etd-06152006-172706 |
| Date | 19 June 2006 |
| Creators | Issariyakul, Titipong |
| Contributors | Peng, Ding-Yu, Hertz, P. Barry, Evitts, Richard W., Dalai, Ajay K., Bakhshi, Narendra N. |
| Publisher | University of Saskatchewan |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://library.usask.ca/theses/available/etd-06152006-172706/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Saskatchewan or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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