Batch Esterification of Free Fatty Acid in Crude Palm Oil with Ethanol Assisted by Ultrasonic Irradiation

Thanet Waisuwan, Chakrit Tongurai

Abstract


One of the obstacles in transesterification of crude palm oil (CPO), a raw material in biodiesel production, is its free fatty acid (FFA) content which causes soap formation and lowers the ester yield. This study investigated FFA reduction using batch esterification of FFA with ethanol, having sulfuric acid as a catalyst together with ultrasonic irradiation. Taguchi method was used in the experimental design. Results showed that FFA content could be reduced from 5.1 to 0.5 wt%. The optimum conditions were: sulfuric acid content at 60 wt% of FFA, 30:1 molar ratio of ethanol to FFA, 60 °C reaction temperature, 1 h reaction time, and 75% amplitude of acoustic power. The esterification not only reduced the FFA content, but also simultaneously lowered the phosphorus content from 11.24 to 1.46 mg/kg. One obvious advantage of this method is that no external source of heat is required for the reaction; the heat could be generated by cavitation resulting from ultrasonic activity. Comparing with the traditional stirring method, esterification by ultrasonic irradiation yielded no significant difference on FFA reduction. The esterification process had also been proven an efficient alternative to simultaneously reduce FFA and phosphorus content in the CPO.

Keywords


Biodiesel Production; Crude Palm Oil; Esterification; Free Fatty Acid; Ultrasonic Irradiation

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References


A. Srivastava, and R. Prasad, “Triglycerides-based diesel fuelsâ€, Renewable and Sustainable Energy Reviews, vol. 4, pp. 111-133, 2000.

K. Addison, “Oil yields and characteristicsâ€, Available online: http:// www.journeytoforever.org /biodiesel_ yield.html 2009; (01/02/2009).

T. Vanichseni, S. Intaravichai, B. Saitthiti, and T. Kiatiwat, “Potential Biodiesel Production from Palm Oil for Thailandâ€, Kasetsart Journal, vol. 36, pp. 83-87, 2002.

H. D. Hanh, N. T. Dong, K. Okitsu, R. Nishimura, and Y. Maeda, “Biodiesel production by esterification of oleic acid with short-chain alcohols under ultrasonic irradiation conditionâ€, Renewable Energy, vol. 34, pp. 780–783, 2009.

B. Freedman, E. H. Pryde, and T. L. Mounts, “Variable affecting the yields of fatty ester from transesterified vegetable oilsâ€, JAOCS, vol. 61, pp. 1638-1643, 1984.

D. Kusdiana, and S. Saka, “Effects of water on biodiesel fuel production by supercritical methanol treatmentâ€, Bioresource Technology, vol. 92, pp. 289-295, 2004.

M. C. Hsiao, C. C. Lin, Y. H. Chang, and L. C. Chen, “Ultrasonic mixing and closed microwave irradiation-assisted transesterification of soybean oilâ€, Fuel, vol. 89, pp. 3618-3622, 2010.

F. F. P. Santos, J. Q. Malveira, M. G. A. Cruz, and F. A. N. Fernandes, “Production of biodiesel by ultrasound assisted esterification of Oreochromis niloticus oilâ€, Fuel, vol. 89, pp. 275-279, 2010.

K. S. Suslick, Sonochemistry, In: R. E. Kirk, D. F. Othmer, editors, Kirk-Othmer Encyclopedia of Chemical Technology, 4th edition, New York, USA: John Wiley & Sons, Inc., 1998, pp. 516-541.

L. H. Thompson, and L. K. Doraiswamy, “Sonochemistry: Science and Engineering (Reviews)â€, Ind Eng Chem Res, vol. 38, pp. 1215-1249, 1999.

E. V. Rokhina, and P. Lens, “Virkutyte J. Low-frequency ultrasound in biotechnology: state of the artâ€, Trends in Biotechnology, vol. 27, pp. 298-306, 2009.

T. Waisuwan, S. Sukmanee, and C. Tongurai, “ Batch process esterification of crude palm oil with ethanol assisted under ultrasonic irradiationâ€, The 2011 International Conference on Alternative Energy in Developing Countries and Emerging Economies (2011 AEDCEE), Hat Yai, Thailand, pp. 69-72, 25-28 May 2011.

G. S. Peace, Taguchi Methods: A Hands-on Approach, New York: Addison-Wesley Publishing; 1993. 522 p.

A. Kalva, T. Sivasankar, and V. S. Moholkar, “Physical Mechanism of Ultrasound-Assisted Synthesis of Biodieselâ€, Ind. Eng. Chem. Res., vol. 48, pp. 534-544, 2009.

O. S. Stamenkovic, M. L. Lazie, Z. B. Todorovic, V. B. Veljkovic, and D. U. Skala, “The effect of agitation intensity on alkaline-catalyzed methanolysis of sunflower oilâ€, Bioresource Technology, vol. 98, pp. 2688-2699, 2007.

J. Ji, J. Wang, Y. Li, Y. Yu, and Z. Xu, “Preparation of Biodiesel with the help of ultrasonic and hydrodynamic cavitationâ€, Ultrasonics, vol. 44, pp. 411-414, 2006.

B. Freedman, M. O. Bagby, “Heats of combustion of fatty esters and triglyceridesâ€, JAOCS, vol. 66, pp. 1601-1605, 1989.

A. Osmont, L. Catoire, and I. Gokalp, “Ab initio study of some radicals of fatty acids methyl esters†3rd European Combustion Meeting, Chania, Crete, Greece, pp. 1-6, 2007.




DOI (PDF): https://doi.org/10.20508/ijrer.v4i2.1173.g6283

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