Biofuels (alcohols and biodiesel) applications as fuels for internal combustion engines
TL;DR: In this article, a review of the production, characterization and current statuses of vegetable oil and biodiesel as well as the experimental research work carried out in various countries is presented.
About: This article is published in Progress in Energy and Combustion Science.The article was published on 2007-06-01. It has received 2891 citations till now. The article focuses on the topics: Diesel fuel & Biodiesel.
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TL;DR: An up-to-date review of the literature available on the subject of liquid bio-fuels can be found in this article, which includes information based on the research conducted globally by scientists according to their local socio-cultural and economic situations.
1,948 citations
TL;DR: In this article, the authors collected and analyzed the body of work written mainly in scientific journals about diesel engine emissions when using biodiesel fuels as opposed to conventional diesel fuels, focusing on the most concerning emissions: nitric oxides and particulate matter.
1,768 citations
TL;DR: In this article, a detailed review has been conducted to highlight different related aspects to the biodiesel industry, including, biodiesel feedstocks, extraction and production methods, properties and qualities of biodiesel, problems and potential solutions of using vegetable oil, advantages and disadvantages of biodies, the economical viability and finally the future of the future biodiesel.
Abstract: As the fossil fuels are depleting day by day, there is a need to find out an alternative fuel to fulfill the energy demand of the world. Biodiesel is one of the best available resources that have come to the forefront recently. In this paper, a detailed review has been conducted to highlight different related aspects to biodiesel industry. These aspects include, biodiesel feedstocks, extraction and production methods, properties and qualities of biodiesel, problems and potential solutions of using vegetable oil, advantages and disadvantages of biodiesel, the economical viability and finally the future of biodiesel. The literature reviewed was selective and critical. Highly rated journals in scientific indexes were the preferred choice, although other non-indexed publications, such as Scientific Research and Essays or some internal reports from highly reputed organizations such as International Energy Agency (IEA), Energy Information Administration (EIA) and British Petroleum (BP) have also been cited. Based on the overview presented, it is clear that the search for beneficial biodiesel sources should focus on feedstocks that do not compete with food crops, do not lead to land-clearing and provide greenhouse-gas reductions. These feedstocks include non-edible oils such as Jatropha curcas and Calophyllum inophyllum , and more recently microalgae and genetically engineered plants such as poplar and switchgrass have emerged to be very promising feedstocks for biodiesel production. It has been found that feedstock alone represents more than 75% of the overall biodiesel production cost. Therefore, selecting the best feedstock is vital to ensure low production cost. It has also been found that the continuity in transesterification process is another choice to minimize the production cost. Biodiesel is currently not economically feasible, and more research and technological development are needed. Thus supporting policies are important to promote biodiesel research and make their prices competitive with other conventional sources of energy. Currently, biodiesel can be more effective if used as a complement to other energy sources.
1,496 citations
Cites background from "Biofuels (alcohols and biodiesel) a..."
...pinnata oil has been described in the literature [29,58,65,88,89,91,94,95]....
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...Table 15 Known problems, probable cause and potential solutions for using straight vegetable oil in diesel engines [58,81,89,91,179]....
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...Table 15 highlights the problems, probale causes and the potential solutions [8,43,53,58,80,81,88,89,99]....
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...Table 14 The chemical structures of common fatty acids [38,46,51,75,89,129]....
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TL;DR: Large biodiversity losses will only be averted if future oil palm expansion is managed to avoid deforestation, and strong overlap between areas suitable for oil palm and those of most importance for biodiversity is reviewed.
Abstract: Oil palm is one of the world's most rapidly increasing crops. We assess its contribution to tropical deforestation and review its biodiversity value. Oil palm has replaced large areas of forest in Southeast Asia, but land-cover change statistics alone do not allow an assessment of where it has driven forest clearance and where it has simply followed it. Oil palm plantations support much fewer species than do forests and often also fewer than other tree crops. Further negative impacts include habitat fragmentation and pollution, including greenhouse gas emissions. With rising demand for vegetable oils and biofuels, and strong overlap between areas suitable for oil palm and those of most importance for biodiversity, substantial biodiversity losses will only be averted if future oil palm expansion is managed to avoid deforestation.
1,235 citations
Cites background from "Biofuels (alcohols and biodiesel) a..."
...As a substitute for diesel, palm oil is less suitable than other vegetable oils owing to its high viscosity, lower energy density and high flash point [ 66 ]....
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TL;DR: In this article, the effect of biodiesel on engine power, economy, durability and emissions including regulated and non-regulated emissions, and the corresponding effect factors are surveyed and analyzed in detail.
Abstract: As a renewable, sustainable and alternative fuel for compression ignition engines, biodiesel instead of diesel has been increasingly fueled to study its effects on engine performances and emissions in the recent 10 years. But these studies have been rarely reviewed to favor understanding and popularization for biodiesel so far. In this work, reports about biodiesel engine performances and emissions, published by highly rated journals in scientific indexes, were cited preferentially since 2000 year. From these reports, the effect of biodiesel on engine power, economy, durability and emissions including regulated and non-regulated emissions, and the corresponding effect factors are surveyed and analyzed in detail. The use of biodiesel leads to the substantial reduction in PM, HC and CO emissions accompanying with the imperceptible power loss, the increase in fuel consumption and the increase in NOx emission on conventional diesel engines with no or fewer modification. And it favors to reduce carbon deposit and wear of the key engine parts. Therefore, the blends of biodiesel with small content in place of petroleum diesel can help in controlling air pollution and easing the pressure on scarce resources without significantly sacrificing engine power and economy. However, many further researches about optimization and modification on engine, low temperature performances of engine, new instrumentation and methodology for measurements, etc., should be performed when petroleum diesel is substituted completely by biodiesel.
1,181 citations
References
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TL;DR: In this article, the transesterification reaction is aected by molar ratio of glycerides to alcohol, catalysts, reaction temperature, reaction time and free fatty acids and water content of oils or fats.
4,902 citations
"Biofuels (alcohols and biodiesel) a..." refers background or methods in this paper
...The effects of FFA and water on transesterification of beef tallow with methanol were investigated by Ma and Hanna [66]....
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...Water content was a more critical variable in the transesterification process than FFA [66]....
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...reasons for the problems and the potential solutions are shown in Table 6 [65,66]....
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...Some short-term experiments used up to a 50/50 ratio [66]....
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...The effect of moisture and FFA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....
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TL;DR: In this paper, the authors showed that the conversion to methyl, ethyl and butyl esters from cottonseed, peanut, soybean and sunflower oils can be done in 1 hr with an alkaline catalyst.
Abstract: Transesterification reaction variables that affect yield and purity of the product esters from cottonseed, peanut, soybean and sunflower oils include molar ratio of alcohol to vegetable oil, type of catalyst (alkaline vs acidic), temperature and degree of refinement of the vegetable oil. With alkaline catalysts (either sodium hydroxide or methoxide), temperatures of 60 C or higher, molar ratios of at least 6 to 1 and with fully refined oils, conversion to methyl, ethyl and butyl esters was essentially complete in 1 hr. At moderate temperatures (32 C), vegetable oils were 99% transesterified in ca. 4 hr with an alkaline catalyst. Transesterification by acid catalysis was much slower than by alkali catalysis. Although the crude oils could be transesterified, ester yields were reduced because of gums and extraneous material present in the crude oils.
1,990 citations
"Biofuels (alcohols and biodiesel) a..." refers background or methods in this paper
...[69] studied the effect of molar ratio (from 1:1 to 6:1) on ester conversion with vegetable oils....
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...[69] transesterified peanut, cottonseed, sunflower and soybean oils under the condition of methanol to oil ratio of 6:1, 0....
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...[69] studied the transesterification of refined soybean oil with methanol (6:1), 1% NaOH catalyst, at three different temperatures 60, 45 and 32 1C....
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...Sodium hydroxide or sodium methoxide reacted with moisture and carbon dioxide in the air, which diminished their effectiveness [69]....
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...Further increase in catalyst concentration does not increase the conversion and it adds to extra costs because it is necessary to remove the catalyst from the reaction products at the end [64,69,70]....
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TL;DR: The main advantages of using biodiesel are its renewability, better-quality exhaust gas emissions, its biodegradability and given that all the organic carbon present is photosynthetic in origin, it does not contribute to a rise in the level of carbon dioxide in the atmosphere and consequently to the greenhouse effect as mentioned in this paper.
Abstract: Efforts are under way in many countries, including India, to search for suitable alternative diesel fuels that are environment friendly. The need to search for these fuels arises mainly from the standpoint of preserving the global environment and the concern about long-term supplies of conventional hydrocarbon-based diesel fuels. Among the different possible sources, diesel fuels derived from triglycerides (vegetable oils/animal fats) present a promising alternative to substitute diesel fuels. Although triglycerides can fuel diesel engines, their high viscosities, low volatilities and poor cold flow properties have led to the investigation of various derivatives. Fatty acid methyl esters, known as biodiesel, derived from triglycerides by transesterification with methanol have received the most attention. The main advantages of using biodiesel are its renewability, better-quality exhaust gas emissions, its biodegradability and given that all the organic carbon present is photosynthetic in origin, it does not contribute to a rise in the level of carbon dioxide in the atmosphere and consequently to the greenhouse effect.
1,733 citations
"Biofuels (alcohols and biodiesel) a..." refers background in this paper
...Table 5 Physical and thermal properties of vegetable oils [64]...
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...2 diesel, in spite of the lower cetane number and energy content [64]....
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...Table 4 Chemical composition of vegetable oils [64]...
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...Table 3 Chemical structure of common fatty acids [64]...
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...Table 7 Properties of Biodiesel prepared from vegetable oils [64]...
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TL;DR: In this paper, a technique is described to reduce the free fatty acids content of these feedstocks using an acid catalyzed pretreatment to esterify the free acids before transesterifying the triglycerides with an alkaline catalyst to complete the reaction.
Abstract: Biodiesel is an alternative fuel for diesel engines consisting of the alkyl monoesters of fatty acids from vegetableoils or animal fats. Most of the biodiesel that is currently made uses soybean oil, methanol, and an alkaline catalyst. The highvalue of soybean oil as a food product makes production of a costeffective fuel very challenging. However, there are largeamounts of lowcost oils and fats such as restaurant waste and animal fats that could be converted to biodiesel. The problemwith processing these low cost oils and fats is that they often contain large amounts of free fatty acids (FFA) that cannot beconverted to biodiesel using an alkaline catalyst. In this study, a technique is described to reduce the free fatty acids contentof these feedstocks using an acidcatalyzed pretreatment to esterify the free fatty acids before transesterifying the triglycerideswith an alkaline catalyst to complete the reaction. Initial process development was performed with synthetic mixturescontaining 20% and 40% free fatty acids, prepared using palmitic acid. Process parameters such as the molar ratio of alcohol,type of alcohol, acid catalyst amount, reaction time, and free fatty acids level were investigated to determine the best strategyfor converting the free fatty acids to usable esters. The work showed that the acid level of the high free fatty acids feedstockscould be reduced to less than 1% with a 2step pretreatment reaction. The reaction mixture was allowed to settle betweensteps so that the watercontaining alcohol phase could be removed. The 2step pretreatment reaction was demonstrated withactual feedstocks, including yellow grease with 12% free fatty acids and brown grease with 33% free fatty acids. After reducingthe acid levels of these feedstocks to less than 1%, the transesterification reaction was completed with an alkaline catalystto produce fuelgrade biodiesel.
1,322 citations
"Biofuels (alcohols and biodiesel) a..." refers background in this paper
...The problem with processing these low-cost oils and fats is that they often contain large amounts of FFA that cannot be converted to biodiesel using an alkaline catalyst [93]....
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TL;DR: In this article, the transesterification of vegetable oils with methanol as well as the main uses of the fatty acid methyl esters are reviewed. But, the anchored catalysts show leaching problems.
Abstract: The transesterification of vegetable oils with methanol as well as the main uses of the fatty acid methyl esters are reviewed. The general aspects of this process and the applicability of different types of catalysts (acids, alkaline metal hydroxides, alkoxides and carbonates, enzymes and non-ionic bases, such as amines, amidines, guanidines and triamino(imino)phosphoranes) are described. Special attention is given to guanidines, which can be easily heterogenized on organic polymers. However, the anchored catalysts show leaching problems. New strategies to obtain non-leaching guanidine-containing catalysts are proposed. Finally, several applications of fatty acid esters, obtained by transesterification of vegetable oils, are described.
1,293 citations