Ethanolysis of Soybean Oil into Biodiesel : Process Optimization via Central Composite Design

  • Tippayawong Nakorn (Department of Mechanical Engineering, Faculty of Engineering, Chiang Mai University) ;
  • Kongjareon Eaksit (Department of Mechanical Engineering, Faculty of Engineering, Chiang Mai University) ;
  • Jompakdee Wasan (Department of Mechanical Engineering, Faculty of Engineering, Chiang Mai University)
  • Published : 2005.10.01

Abstract

A process for production of ethyl ester for use as biodiesel has been studied. The sodium hydroxide catalyzed transesterification of soybean oil with ethanol was carried out at different molar ratio of alcohol to oil, reaction temperature and catalyst amount for a constant agitation in two hours of reaction time. Central composite design and response surface methodology were used to determine optimum condition for producing biodiesel. It was found that ethanol to oil ratio and catalyst concentration have a positive influence on ester conversion as well as interaction effects between the three factors considered. An empirical model obtained was able to predict conversion as a function of ethanol to oil molar ratio, reaction temperature and catalyst concentration adequately. Optimum condition for soybean ethyl ester production was found to be moderate ethanol to oil ratio (10.5: 1), mild temperature range ($70^{\circ}C$) and high catalyst concentrations ($1.0\%$wt), with corresponding ester conversion of $93.0\%$.

Keywords

References

  1. Bhattacharyya, S. and Reddy, C. S., 1994, 'Vegetable Oils as Fuels for Internal Combustion Engines : a Review,' Journal of Agricultural Engineering Research, Vol. 57, pp. 157-166 https://doi.org/10.1006/jaer.1994.1015
  2. Box, J. and Wilson, W., 1951, 'Central Composite Designs,' Journal of the Royal Statistical Society, Vol. 13, pp.1-35
  3. Canakci, M. and Van Gerpen, J., 1999, 'Biodiesel Production via Acid Catalysis,' Transactions of the ASAE, Vol. 42, pp. 1203-1210
  4. Fukuda, H., Kondo, A. and Noda, H., 2001, 'Biodiesel Fuel Production by Transesterification of Oils,' Journal of Bioscience and Bioengineering, Vol. 92, pp. 405-416 https://doi.org/10.1263/jbb.92.405
  5. Graboski, M. S. and McCormick, R. L., 1998, 'Combustion of Fat and Vegetable Oil Derived Fuels in Diesel Engines,' Progress in Energy and Combustion Science, Vol. 24, pp. 125-164 https://doi.org/10.1016/S0360-1285(97)00034-8
  6. Kim, M. and Heo, S., 2003, 'Conservative Quadratic RSM combined with Incomplete Small Composite Design and Conservative Least Squares Fitting,' KSME International Journal, Vol. 17, pp. 698-707
  7. Ma, F. and Hanna, M. A., 1999, 'Biodiesel Production: a Review,' Bioresource Technology, Vol. 70, pp. 1-15 https://doi.org/10.1016/S0960-8524(99)00025-5
  8. Montgomery, D. C., 2001, Design and Analysis of Experiments, John Wiley & Sons, New York
  9. Muniyappa, P. R., Brammer, S. C. and Noureddini, H., 1996, 'Improved Conversion of Plant Oils and Animal Fats into Biodiesel and Co-product,' Bioresource Technology, Vol. 56, pp. 19-24 https://doi.org/10.1016/0960-8524(95)00178-6
  10. Pryde, E. H., 1983, 'Vegetable Oils as Diesel Fuel: Overview,' Journal of the American Oil Chemists' Society, Vol. 60, pp. 1557-1558
  11. Ryu, K. and Oh, Y., 2003, 'A Study on the Usability of Biodiesel Fuel Derived from Rice Bran Oil as an Alternative Fuel for IDI Diesel Engine,' KSME International Journal, Vol. 17, pp. 310-317
  12. Sanchez, N., Martinez, M. and Aracil, J., 1997, 'Selective Esterification of Glycerine to 1-Glycerol Monooleate. 2. Optimization Studies,' Industrial & Engineering Chemistry Research, Vol. 36, pp. 1529-1534 https://doi.org/10.1021/ie960313w
  13. Shay, E. G., 1993, 'Diesel Fuel from Vegetable Oils: Status and Opportunities,' Biomass & Bioenergy, Vol. 4, pp. 227-242 https://doi.org/10.1016/0961-9534(93)90080-N
  14. Srivastava, A. and Prasad, R., 2000, 'Triglycerides-based Diesel Fuels,' Renewable and Sustainable Energy Reviews , Vol. 4, pp. 111-133 https://doi.org/10.1016/S1364-0321(99)00013-1
  15. Vicente, G., Coteron, A., Martinez, M. and Aracil, J., 1998, 'Application of the Factorial Design of Experiments and Response Surface Methodology to Optimize Biodiesel Production,' Industrial Crops and Products, Vol. 8, pp. 29-35 https://doi.org/10.1016/S0926-6690(97)10003-6
  16. Wibulswas, P., 2002, 'Development of Biomass Liquid Fuels for Transportation in Thailand,' Journal of the Royal Institute of Thailand, Vol. 27, pp. 429-433