Possible methods for biodiesel production. Renew Sust Energ Rev

Renewable and Sustainable Energy Reviews (Impact Factor: 5.9). 08/2007; 11(6):1300-1311. DOI: 10.1016/j.rser.2005.08.006

ABSTRACT Biodiesel production is a very modern and technological area for researchers due to the relevance that it is winning everyday because of the increase in the petroleum price and the environmental advantages. In this work it is made a review of the alternative technological methods that could be used to produce this fuel. Different studies have been carried out using different oils as raw material, different alcohol (methanol, ethanol, buthanol) as well as different catalysts, homogeneous ones such as sodium hydroxide, potassium hydroxide, sulfuric acid and supercritical fluids, and heterogeneous ones such as lipases. In this work advantages and disadvantages of technologies are listed and for all of them a kinetics model is introduced.

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    • "Alkali-catalyzed transesterification is currently used in the commercial production of biodiesel. With base as catalyst, waste oils rich in free fatty acids (FFAs) and water are difficult to be utilized efficiently since the former result in producing saponified products, while the latter hinders complete conversion of oils (Marchetti et al., 2007; Imahara et al., 2008). Acid transesterification is an efficient way to produce biodiesel if the raw material oil has relative high FFA content. "
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    • "Thus, biodiesel is usually blended with conventional diesel. There are several techniques to overcome this problem, including pyrolysis, micro-emulsification, dilution and transesterification (Marchetti et al., 2007). Among these techniques, transesterification offers the most promise for lowering the viscosity. "
    Aerosol and Air Quality Research 01/2015; DOI:10.4209/aaqr.2014.11.0299 · 2.09 Impact Factor
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    • "As the reaction is reversible, an excess amount of alcohol is required to shift the equilibrium to the product side. The variables that affect the transesterification process are reaction time, reaction temperature, intensity of mixing, ratio of oil to alcohol, concentration and type of catalyst and feedstock [6] [7] [8] [9] [10] [11]. Often the transesterification reaction is severely limited by mass transfer giving much lower rates of reaction and hence there is always scope for "
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    ABSTRACT: Biodiesel is one of the most promising alternatives for fossil fuels but the synthesis of biodiesel is hampered by significant mass transfer and equilibrium limitations along with higher energy requirements especially for the downstream processing. The current investigation focuses on the intensification of transesterification reaction for the production of biodiesel using palm oil as the feedstock in the presence of KOH catalyst. For the first time a triple frequency ultrasonic reactor (combination of 28-40-70 kHz) has been used for the intensification using palm oil with an objective of reducing the reaction time, molar ratio as well as possibly increasing the yield of biodiesel. The optimized parameters of reaction time, reaction temperature, and the obtained yield (%) in the ultrasound assisted process have been compared with the conventional approach of mechanical stirring. Also, within the ultrasound assisted approach, single, dual and triple frequency mode of operation has been compared to achieve an effective intensification. It has been observed that the cavitation effects were higher for the triple frequency operation as compared to the dual and single frequency operations. The maximum yield obtained with the triple frequency approach, at 3:1 molar ratio of methanol and oil with 1 wt% potassium hydroxide as catalyst, was 93% with significantly reduced reaction time of 15 min as compared to the 3 h required in conventional stirring to achieve 75% yield. The results of this investigation support that coupling the ultrasound frequency is useful in intensifying the transesterification reaction.
    Fuel Processing Technology 12/2014; 128:388-393. DOI:10.1016/j.fuproc.2014.08.002 · 3.35 Impact Factor
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