Vegetable Oil Esters Research Articles

Overview on the current trends in biodiesel production

The finite nature of fossil fuels necessitates consideration of alternative fuels from renewable sources. The term biofuel refers to liquid, gas and solid fuels predominantly produced from biomass. Biofuels include bioethanol, biomethanol, biodiesel and biohydrogen. Biodiesel, defined as the monoalkyl esters of vegetable oils or animal fats, is an attractive alternative fuel because it is environmentally friendly and can be synthesized from edible and non-edible oils. Here, we review the various methods for the production of biodiesel from vegetable oil, such as direct use and blending, microemulsion, pyrolysis and transesterification. The advantages and disadvantages of the different biodiesel-production methods are also discussed. Finally, we analyze the economics of biodiesel production using Malaysia as a case study.

Optimization of esters of nerium biodiesel in a diesel engine

The methyl and ethyl esters of vegetable oils, known as biodiesel are becoming increasingly popular because of their low environmental impact and potential as a green alternative fuel for diesel engine. In the present work, methyl and ethyl esters of nerium oil were prepared by transesterification using both methanol and ethanol. However, viscosity of ethyl esters of nerium oil (EEON) was slightly higher than that of methyl esters of nerium oil (MEON). A single cylinder stationary kirloskar engine is used to compare the Performance and Emission and Combustion characteristics between pure diesel and nerium blends. The nerium oil blends are in percentage of 20%, 40%, 60%, 80%, and 100% of nerium oil to 80%, 60%, 40%, 20% and 0% of diesel. Results show that methyl esters of nerium oil (MEON) produced slightly higher efficiency than ethyl esters of nerium oil (EEON). Exhaust emissions and Combustion characteristics of methyl esters of nerium oil (MEON) were also higher than ethyl esters of nerium oil (EEON). Hence methyl and ethyl esters of nerium blend can be used in existing diesel engines without compromising the engine performance.

Prediction of the density and viscosity in biodiesel blends at various temperatures

Biodiesel defined as mono-alkyl esters of vegetable oils and animal fats, has had a considerable development and great acceptance as an alternative fuel for diesel engines. Density and viscosity are two important physical properties to affect the utilization of biodiesel as fuel. In this work, mixtures of biodiesel and ultra low sulfur diesel (ULSD) were used to study the variation of density ( ρ) and kinematic viscosity ( η) as a function of percent volume ( V) and temperature ( T), experimental measurements were carried out for six biodiesel blends at nine temperatures in the range of 293.15–373.15 K. Both, density and viscosity increases because of the increase in the concentration of biodiesel in the blend, and both of them decrease as temperature increases. One empirical correlation was proposed to estimate the density: ρ = α· V + β · T + δ ; and three empirical correlations were developed to predict the kinematic viscosity: η = exp[ln( γ) + ϕ· V + ω / T + λ · V/ T 2], η = exp[ln( γ) + ω/ T + λ · V/ T 2] and η = exp[ln( γ) + ω/ T + λ · V/ T]. The corresponding parameters were optimized by the Levenberg–Marquardt method. The estimated values of density and viscosity are in good agreement with the experimental data because absolute average prediction errors of 0.02% and 2.10% were obtained in the Biodiesel(1) + ULSD(2) system studied in this work.

Biofuels: The Role of Biodiesel and Improving Its Performance

ABSTRACTConcerns about the availability and long-term supply of petroleum-derived fuels have caused the search for alternative sources of energy. Liquid fuels will for some applications be necessary for an indefinite period of time. Therefore, defining relevant feedstocks, producing fuels from these feedstocks and the properties of these fuels are critical issues. Fuels powering compression-ignition (diesel) and turbine (jet) engines are among these liquid energy sources. Biodiesel, defined as the mono-alkyl esters of vegetable oils, animal fats or other triacylglycerol-based feedstocks plays a prominent role in this connection as alternative to petrodiesel fuels. Important issues facing biodiesel are feedstock supply as not enough vegetable oil is available to replace the whole petrodiesel market and the issue of fuel properties, especially cold flow and oxidative stability. The search for additional feedstocks coupled with the food vs fuel issue has increased interest in inedible oils derived from sources such as used cooking oils, jatropha and algae. However, biodiesel from these sources, as biodiesel derived from classical sources such as commodity vegetable oils, must meet performance criteria and this is not necessarily the case. Therefore, modifying the composition of biodiesel, i.e., its fatty ester profile, is a critical issue to enhance its use in the marketplace. Esters of specific fatty acids impart improved properties to biodiesel with esters of decanoic and palmitoleic acid displaying favorable properties for enrichment in biodiesel feedstocks. Renewable diesel is another fuel that can be obtained from triacylglycerol-based feedstocks. In its composition, i.e. alkane-type hydrocarbons, it more closely resembles petrodiesel fuel. While biodiesel is obtained from triacylglycerol-based feedstocks via a transesterification reaction using an alcohol in presence of a catalyst under mild conditions, renewable diesel can be obtained from such feedstocks via a hydrodeoxygenation reaction using hydrogen in presence of a catalyst under more severe conditions. Biodiesel and renewable diesel are compared regarding their production and properties and it is suggested that each fuel has a role to play in an alternative energy mix based on its properties.

Mathematical Modeling for the Prediction of Fuel Properties of Biodiesel from their FAME Composition

The mono-alkyl esters of vegetable oils or animal fats, known as biodiesel have received significant attention as an alternative diesel fuel. In the present study fuel properties like viscosity, density and High Heat Value (HHV) of ten biodiesels namely Corn, Cottonseed, Linseed, Rapeseed, Safflower, Soybean, Sunflower, Mahua, Jatropha and Palm are predicted using their FAME ( Fatty Acid Methyl Ester) composition by regression analysis and the results obtained are compared and found to be in good agreement with reported literature values.

Biodiesel for Future Transportation Energy Needs

Biodiesel is a natural, renewable transportation fuel. Biodiesel is the best candidate for diesel fuels in diesel engines with no alterations. Biodiesel is a nontoxic, biodegradable alternative to petroleum diesel that substantially reduces air pollution. Biodiesel fuel typically comprises lower alkyl fatty acid (chain length C14-C22), esters of short-chain alcohols, primarily, methanol or ethanol. Methyl esters of vegetable oils have several outstanding advantages over other new-renewable and clean engine fuel alternatives. Biodiesel production using inedible vegetable oil, waste oil, and grease has become more attractive recently. The economic performance of a biodiesel plant can be determined once certain factors are identified, such as plant capacity, process technology, raw material cost, and chemical costs. The cost of biodiesel fuels varies depending on the base stock, geographic area, variability in crop production from season to season, the price of crude petroleum, and other factors. Biodiesel seems to be a realistic fuel for the future; it has become more attractive recently because of its environmental benefits.

Biodiesel: Current Trends and Properties

Biodiesel, an alternative to petroleum-derived diesel fuel, is defined as the mono-alkyl esters of vegetable oils and animal fats. Several current issues affecting biodiesel that are briefly discussed include the role of new feedstocks in meeting increased demand for biodiesel and circumventing the food versus fuel issue, biodiesel production, as well as fuel properties and their improvement.

Comparative Performance, Emission, and Combustion Characteristics of Rice-Bran Oil and Its Biodiesel in a Transportation Diesel Engine

The methyl esters of vegetable oils known as biodiesel are becoming increasingly popular because of their low environmental impact and potential as a green alternative fuel for diesel engines. Methyl ester of rice-bran oil (RBOME) is prepared through the process of transesterification. In the present investigation, experiments have been carried out to examine the performance, emission, and combustion characteristics of a direct-injection transportation diesel engine running with diesel, 20% blend of rice-bran oil (RBO), and 20% blend of RBOME with mineral diesel. A four-stroke, four-cylinder, direct-injection transportation diesel engine (MDI 3000) was instrumented for the measurement of the engine performance, emissions, in-cylinder pressure-crank angle history, rate of pressure rise, and other important combustion parameters such as instantaneous heat release rate, cumulative heat release rate, mass fraction burned, etc. A careful analysis of the performance, emissions, combustion, and heat release parameters has been carried out. HC, CO, and smoke emissions for RBO and RBOME blends were lower than mineral diesel while NOx emissions were almost similar and brake specific fuel consumption (BSFC) was slightly higher than mineral diesel. Combustion characteristics were quite similar for the three fuels.

Biodiesel Derived from a Model Oil Enriched in Palmitoleic Acid, Macadamia Nut Oil

Numerous vegetable oils, animal fats, or other feedstocks have been investigated to obtain biodiesel, defined as the monoalkyl esters of vegetable oils and animal fats. While biodiesel is competitive with petrodiesel, technical problems facing biodiesel include cold flow and oxidative stability. Most biodiesel fuels largely contain five fatty acids, palmitic, stearic, oleic, linoleic, and linolenic fatty acids, in varying amounts in their fatty acid profiles. Dependent upon the major fatty acids present, biodiesel from different feedstocks faces these technical problems with varying severity. As previous work has indicated, enrichment of other fatty acids, such as decanoic or palmitoleic acid, in the fatty acid profile may be advantageous to address the technical issues facing biodiesel. In this work, an oil moderately enriched in palmitoleic acid (approximately 16−20%), macadamia nut oil, was selected for producing the corresponding biodiesel fuel and investigating its fuel properties. Methyl esters of m...

Combustion, performance and emission analysis of diesel engine fuelled with methyl esters of Pongamia oil

The methyl esters of vegetable oils, known as biodiesel are increasingly becoming popular because of their low environmental impact and potential as a green alternative fuel for diesel engine, and that they would not require significant modification of existing engine hardware. Methyl ester of Pongamia oil (PME) is derived through transesterification process. Experimental investigations have been carried out to examine properties, performance and emissions of different blends (B00, B20, B40, B60, B80 and B100) of PME comparison to diesel. A computer assisted single cylinder constant speed water cooled four stroke direct diesel engine (5 HP), which is commonly used in the agricultural sector for driving the pumps and small electrical generators is selected for the experimental investigation. The performance, emissions and combustion characteristics are analysed. The combustion parameters considered for this analysis are cylinder pressure and rate of heat release. The brake thermal efficiency is slightly reduced and hydrocarbon, carbon monoxide and smoke emissions in the exhaust are reduced when fuelled with methyl esters compared to diesel. But the NOx emissions are high when fuelled with methyl esters compared to diesel. [Received: December 11, 2009; Accepted: March 21, 2010]

Catalytic conversions in green aqueous media: Part 4. Selective hydrogenation of polyunsaturated methyl esters of vegetable oils for upgrading biodiesel

This study deals with the influence of operating parameters on the selective hydrogenation of crude polyunsaturated methyl esters of linseed, sunflower and soybean oils in order to achieve high selectivities up to 79.8 mol% of monounsaturated (C18:1) fatty acid methyl esters (FAME) which is 1st generation biodiesel of increased oxidative stability, energy and environmental performance at a low pour point employing water-soluble Rh/TPPTS catalytic complexes [TPPTS = P(C6H4-m-SO3Na)3] in green aqueous/organic two-phase systems. This study also discloses the great potential of biphasic selective catalytic hydrogenation to produce 2nd generation biodiesel from polyunsaturated FAME of alternative, non-food oil feedstocks which are originally not suitable for biodiesel production or give poor quality biodiesel but combine the advantage that they would not affect food production. Because the mixture of methyl esters of linseed oil mainly consists of C18:3 FAME it constitutes a good model to investigate the effects of parameters on the whole spectrum of the stepwise hydrogenation: C18:3 (linolenates) → C18:2 (linoleates) → C18:1 (oleates) C18:0 (stearate) and to obtain first information on the selective hydrogenation of alternative, non-food oils with a high C18:3 FAME content to make them suitable for 2nd generation biodiesel formulations.

Transesterification of Beechnut Oil into Biodiesel in Compressed Methanol

Transesterification reaction of beechnut oil in supercritical methanol was investigated without using the catalyst for the production of fatty acid methyl esters or biodiesel. Experiments have been carried out in the batch-type reaction vessel (autoclave) preheated at 493, 523, and 593 K, and with molar ratios of 1:6–1:40 of the beechnut oil to methanol. The most important variables affecting the methyl ester yield during transesterification reaction are molar ratio of alcohol to vegetable oil and reaction temperature. The yield of alkyl ester increased with increasing the molar ratio of oil to alcohol. In the supercritical methanol transesterification method, the yield of conversion raises 70–95% for the first 10 min. Oil content of beechnut samples used in the experiments are 16–23% by weight. Methyl esters of vegetable oils have several outstanding advantages among other new-renewable and clean engine fuel alternatives.

Correlation between the chemical structure of biodiesel and its physical properties

Biodiesel is a renewable, biodegradable, environmentally benign, energy efficient, substitution fuel which can fulfill energy security needs without sacrificing engine’s operational performance. Thus it provides a feasible solution to the twin crises of fossil fuel depletion and environmental degradation. The properties of the various individual fatty esters that comprise biodiesel determine the overall properties of the biodiesel fuel. In turn, the properties of the various fatty esters are determined by the structural features of the fatty acid and the alcohol moieties that comprise a fatty ester. Better understanding of the structure-physical property relationships in fatty acid esters is of particular importance when choosing vegetable oils that will give the desired biodiesel quality. By having accurate knowledge of the influence of the molecular structure on the properties determined, the composition of the oils and the alcohol used can both be selected to give the optimal performance. In this paper the relationship between the chemical structure and physical properties of vegetable oil esters is reviewed and engineering fatty acid profiles to optimize biodiesel fuel characteristics is highlighted.

Biodiesel production, properties, and feedstocks

Biodiesel, defined as the mono-alkyl esters of vegetable oils or animal fats, is an environmentally attractive alternative to conventional petroleum diesel fuel (petrodiesel). Produced by transesterification with a monohydric alcohol, usually methanol, biodiesel has many important technical advantages over petrodiesel, such as inherent lubricity, low toxicity, derivation from a renewable and domestic feedstock, superior flash point and biodegradability, negligible sulfur content, and lower exhaust emissions. Important disadvantages of biodiesel include high feedstock cost, inferior storage and oxidative stability, lower volumetric energy content, inferior low-temperature operability, and in some cases, higher NO x exhaust emissions. This review covers the process by which biodiesel is prepared, the types of catalysts that may be used for the production of biodiesel, the influence of free fatty acids on biodiesel production, the use of different monohydric alcohols in the preparation of biodiesel, the influence of biodiesel composition on fuel properties, the influence of blending biodiesel with other fuels on fuel properties, alternative uses for biodiesel, and value-added uses of glycerol, a co-product of biodiesel production. A particular emphasis is placed on alternative feedstocks for biodiesel production. Lastly, future challenges and outlook for biodiesel are discussed.

Cuphea Oil as Source of Biodiesel with Improved Fuel Properties Caused by High Content of Methyl Decanoate

Biodiesel, defined as the monoalkyl esters of vegetable oils and animal fats, is an alternative to conventional petroleum-based diesel fuel. Biodiesel has been prepared from numerous common vegetable oils or fats as well as new or less common feedstocks. Major issues facing biodiesel include several technical aspects such as cold flow and oxidative stability as well as availability of sufficient quantities of fuel. Solutions to the technical problems include the use of additives or modifying the fatty ester composition of biodiesel. While esters of oleic acid possess good fuel properties, esters of other fatty acids also exhibit advantageous fuel properties, even surpassing those of oleic acid esters. Decanoic acid has been shown to be an acid whose esters possess good fuel properties. In this work, a vegetable oil containing a high amount (approximately 65%) of decanoic acid, one of the many known varieties of cuphea oil (PSR 23; a cross of Cuphea viscosissima × C. lanceolata), is reported for the first time as potential biodiesel feedstock. The methyl esters of cuphea oil (biodiesel) were prepared by conventional transesterification, and the 1H NMR spectrum of cuphea methyl esters is reported. The significant fuel properties influenced by fatty ester composition such as cetane number, kinematic viscosity, cold flow, as well as lubricity were determined and evaluated in comparison to biodiesel fuel standards. Cuphea methyl esters generally display more favorable fuel properties than do biodiesel fuels derived from other feedstocks due to the high content of methyl decanoate and as expressed by a cloud point around −9 to −10 °C. Although cuphea oil faces significant technical issues regarding its commercial availability, it appears to be a good potential feedstock for biodiesel and can serve as a model for other potential feedstocks with high decanoic acid content.

Improving biodiesel fuel properties by modifying fatty ester composition

Biodiesel is an alternative to petroleum-derived diesel fuel composed of alkyl esters of vegetable oils, animal fats or other feedstocks such as used cooking oils. The fatty acid profile of biodiesel corresponds to that of its feedstock. Most common feedstocks possess fatty acid profiles consisting mainly of five C16 and C18 fatty acids, namely, palmitic (hexadecanoic), stearic (octadecanoic), oleic (9(Z)-octadecenoic), linoleic (9(Z),12(Z)-octadecadienoic) and linolenic (9(Z),12(Z),15(Z)-octadecatrienoic) acids, with the exception of a few oils such as coconut oil, which contains high amounts of saturated acids in the C12–C16 range or others. While in many respects biodiesel possesses advantages or is competitive with petroleum-derived diesel fuel, virtually all biodiesel fuels, typically the methyl esters, produced from these oils have performance problems such as poor low-temperature properties or insufficient oxidative stability. Considerable research has focused on solving or alleviating these problems and five approaches have been developed. Besides the approach of using additives, changing the fatty ester composition by either varying the alcohol or the fatty acid profile of the oil have been studied. Changing the fatty acid profile can be achieved by physical means, genetic modification of the feedstock or use of alternative feedstocks with different fatty acid profiles. In some cases approaches may overlap. This article briefly summarizes the five approaches currently used with an emphasis on those dealing with changing the fatty ester composition of a biodiesel fuel.

Environmental aspects of biofuels in road transportation

Energy is a vital and growing need for human activities such as transport, agriculture and industry. The transport and agriculture sectors are major consumers of fossil fuel. However, availability of fossil fuels is limited. The use of fossil fuels is of increasing environmental concerns because it produces toxic airborne particulates and greenhouse gases such as CO2. The increasing industrialization and motorization of the world led to a steep rise for the demand of petroleum-based fuels. Hence, it is necessary to seek alternative fuels, which can be produced from resources available locally within the country such as alcohol, biodiesel and vegetable oils. Biodiesel is defined as the mono alkyl esters of vegetable oils or animal fats. Biodiesel is the best candidate for diesel fuels in the diesel engines. The advantage of biodiesel over gasoline and petroleum/diesel is its eco-friendly nature. This article reviews the production, characterization and current status of biofuels mainly biodiesel along with the environmental impacts of particulate matter, greenhouse gas emissions originated from biodiesel.

Progress and recent trends in biodiesel fuels

Fossil fuel resources are decreasing daily. Biodiesel fuels are attracting increasing attention worldwide as blending components or direct replacements for diesel fuel in vehicle engines. Biodiesel fuel typically comprises lower alkyl fatty acid (chain length C 14–C 22), esters of short-chain alcohols, primarily, methanol or ethanol. Various methods have been reported for the production of biodiesel from vegetable oil, such as direct use and blending, microemulsification, pyrolysis, and transesterification. Among these, transesterification is an attractive and widely accepted technique. The purpose of the transesterification process is to lower the viscosity of the oil. The most important variables affecting methyl ester yield during the transesterification reaction are the molar ratio of alcohol to vegetable oil and the reaction temperature. Methanol is the commonly used alcohol in this process, due in part to its low cost. Methyl esters of vegetable oils have several outstanding advantages over other new-renewable and clean engine fuel alternatives. Biodiesel fuel is a renewable substitute fuel for petroleum diesel or petrodiesel fuel made from vegetable or animal fats; it can be used in any mixture with petrodiesel fuel, as it has very similar characteristics, but it has lower exhaust emissions. Biodiesel fuel has better properties than petrodiesel fuel; it is renewable, biodegradable, non-toxic, and essentially free of sulfur and aromatics. Biodiesel seems to be a realistic fuel for future; it has become more attractive recently because of its environmental benefits. Biodiesel is an environmentally friendly fuel that can be used in any diesel engine without modification.

Production of biodiesel fuels from linseed oil using methanol and ethanol in non-catalytic SCF conditions

Abstract Methyl and ethyl esters as biodiesel fuels were prepared from linseed oil with transesterification reaction in non-catalytic supercritical fluids conditions. Biodiesel fuel is a renewable substitute fuel for petroleum diesel fuel made from vegetable or animal fats. Biodiesel fuel has better properties than that of petroleum diesel fuel such as renewable, biodegradable, non-toxic, and essentially free of sulfur and aromatics. The purpose of the transesterification process is to lower the viscosity of the oil. The viscosity values of linseed oil methyl and ethyl esters highly decreases after transesterification process. The viscosity values of vegetable oils vary between 27.2 and 53.6 mm 2 s −1 , whereas those of vegetable oil methyl esters between 3.59 and 4.63 mm 2 s −1 . Compared with no. 2 diesel fuel, all of the vegetable oil methyl esters were slightly viscous. The flash point values of vegetable oil methyl esters are highly lower than those of vegetable oils. The transesterification of linseed oil in supercritical fluids such as methanol and ethanol has proved to be the most promising process. Methanol is the commonly used alcohol in this process, due in part to its low cost. Methyl esters of vegetable oils have several outstanding advantages among other new-renewable and clean engine fuel alternatives. The most important variables affecting the methyl ester yield during the transesterification reaction are molar ratio of alcohol to vegetable oil and reaction temperature. Biodiesel has become more attractive recently because of its environmental benefits. Biodiesel is an environmentally friendly fuel that can be used in any diesel engine without modification.

Moringa oleifera oil: A possible source of biodiesel

Biodiesel is an alternative to petroleum-based conventional diesel fuel and is defined as the mono-alkyl esters of vegetable oils and animal fats. Biodiesel has been prepared from numerous vegetable oils, such as canola (rapeseed), cottonseed, palm, peanut, soybean and sunflower oils as well as a variety of less common oils. In this work, Moringa oleifera oil is evaluated for the first time as potential feedstock for biodiesel. After acid pre-treatment to reduce the acid value of the M. oleifera oil, biodiesel was obtained by a standard transesterification procedure with methanol and an alkali catalyst at 60 °C and alcohol/oil ratio of 6:1. M. oleifera oil has a high content of oleic acid (>70%) with saturated fatty acids comprising most of the remaining fatty acid profile. As a result, the methyl esters (biodiesel) obtained from this oil exhibit a high cetane number of approximately 67, one of the highest found for a biodiesel fuel. Other fuel properties of biodiesel derived from M. oleifera such as cloud point, kinematic viscosity and oxidative stability were also determined and are discussed in light of biodiesel standards such as ASTM D6751 and EN 14214. The 1H NMR spectrum of M. oleifera methyl esters is reported. Overall, M. oleifera oil appears to be an acceptable feedstock for biodiesel.