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
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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- "There are three stepwise reactions, during which triglycerides are gradually transformed through two intermediates – i.e. diglycerides and monoglycerides, into three molecules of FAME and one molecule of glycerol (Pecha, 2009; Ramesh et al., 2006). However, the transesterification reaction is affected by the selected reaction conditions, i.e. the type and amount of catalyst, the type of alcohol, the alcohol/oil molar ratio, the reaction time, the reaction temperature and also the feedstock quality (especially dependent on the free fatty acid content) (Freedman et al., 1984a; Marchetti et al., 2007; Meher et al., 2006). "
ABSTRACT: Annually, a great amount of waste fats and oils not suitable for human consumption or which cannot be further treated are produced around the world. A potential way of utilizing this low-cost feedstock is its conversion into biodiesel. The majority of biodiesel production processes today are based on the utilization of inorganic alkali catalysts. However, it has been proved that an organic base – tetramethylammonium hydroxide – can be used as a very efficient transesterification catalyst. Furthermore, it can be employed for the esterification of free fatty acids – reducing even high free fatty acid contents to the required level in just one step. The work presented herein, is focused on biodiesel production from waste frying oils and animal fats using tetramethylammonium hydroxide at the pilot-plant level. The results showed that the process performance in the pilot unit – using methanol and TMAH as a catalyst, is comparable to the laboratory procedure, even when the biodiesel is produced from waste vegetable oils or animal fats with high free fatty acid content. The reaction conditions were set at: 1.5% w/w of TMAH, reaction temperature 65 °C, the feedstock to methanol molar ratio to 1:6, and the reaction time to 120 min. The conversion of triglycerides to FAME was approximately 98%. The cloud point of the biodiesel obtained from waste animal fat was also determined.
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- "Transesterification is the primary process used to generate biodiesel from high FFA vegetable oil. As a result, low quality biodiesel is obtained because FFA content in oil promotes saponification      . Therefore, high content of free fatty acid oils could be treated via enzyme-catalyzed trans-esterificaton, acidcatalyzed trans-esterifiaction, supercritical and a two-stage process   . "
ABSTRACT: A suitable heterogeneous catalyst for reducing 20wt.% of free fatty acid (FFA) that is contained in vegetable oil to less than 3wt.% through re-esterification was investigated. There were two groups of heterogeneous catalyst used to reduce FFA: 1) zinc compound: Zn, ZnCl2, ZnO and ZnSO4·7H2O, and 2) stannum compound: SnCl4·5H2O and SnCl2·2H2O. The reaction was operated at 150°C under ambient pressure, stirred at 600rpm. with spent retention time of approximately 180min. Final FFA in re-esterification of products, which were cleaned up with centrifuging and hot wet washing, was monitored. The results after centrifuge indicated that only two catalysts (Zn and ZnO) were capable of promoting the reaction and achieving the requirement. Moreover, final FFA in re-esterification of products, which were cleaned up with hot wet washing, was also monitored. It was found that no significant differences existed in the two purification techniques except for the heterogeneous Zn catalyst in re-esterification product. The results showed that thin layer chromatography with a flame ionization detector (TLC/FID) could not detect all of the compositions in the pre-treatment product using Zn as a catalyst. Therefore, ZnO was the most suitable catalyst for effectively reducing FFA via a re-esterification process.
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- "This transesterification reaction depends on some reaction conditions such as temperature, catalyst concentration, speed of stirrer, molar ratios of oil and alcohol. To get maximum conversion, certain major physical and chemical property of the reaction system should be maintained properly , , . Mathematical modeling can be helpful and its implementation in reality would be beneficial in this regard. "
ABSTRACT: Biodiesel is one of promising renewable energy source and used as an alternative of conventional hydrocarbon fuels. Jatropha curcas plant oil (JCPO) is the most cost effective sources of biodiesel. The plant can be cultivated in wastelands and grows on almost any type of territory, even on sandy and saline soils. Judicious agricultural practices and effective crop management of Jatropha curcas is preliminary requisite to get maximum yield of oil. Production of biodiesel by transesterification of Jatropha oil significantly depends on four reaction parameters viz., reaction time, temperature, oil to alcohol molar ratio and stirrer speed. In this work, we have formulated a mathematical model of Jatropha curcas plant, which is affected by many type of pest with the aim to control the pest through Nuclear Polyhedrosis Virus (NPV). Here we have also concentrated on insecticide spraying as controlling measure to reduce the pest, to get maximum yield of Jatropha seeds, which gives Jatropha oil. We have also shown the effect of different variants on mass transfer in biodiesel production from JC oil and how the control theoretic approach flags the maximum production of biodiesel under the mathematical paradigm. Our analytical results provide an idea of the cost effective faster rate of biodiesel production, which satisfies our numerical conclusions.