Biofuels derived from algae can have lower impact on the environment and the food supply than biofuels produced from crops. The strain selection, cultivation method, culture conditions and the ...chemical composition strongly influences the production costs but also the engine's performance and the exhaust gas emissions. The scope of this paper is to make a critical review about the impact of the use of biofuels produced from (micro) algae to power diesel engines. There is a huge disparity in the amount of papers published for algae culture, oil extraction, and biodiesel production compared to reporting performance on diesel engines. This paper presents an analysis of the papers published in this specific field. Generally, a reduction of torque and power output is reported. A wide range of blends up to B50 but also pure biodiesel has been tested. The blend showing results closest to diesel fuel appears to be B20. Several pollutants can be reduced if biofuels from different strains are used but an increase in NOx is generally reported, associated to higher temperatures in the combustion chamber. The use of emulsions instead of blends or neat biodiesel reveals a promising alternative with important reductions of CO2 and NOx. However, the few reports for engine tests present some contradictions, or are lacking important information about the experiments. The assessment of biodiesel produced from algae or microalgae is a field hardly explored and until today some reference papers contain contradictory results or non-well studied behaviors as this survey demonstrates.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK, ZRSKP
In this investigation, puffing and micro-explosion occurrence in emulsified fuels are studied. The emulsified fuels are formulated using a micro-channel emulsifier, a blend of rapeseed oil in diesel ...fuel as continuous phase, water as dispersed phase and Sorbitan Sesquioleate as surfactant. Several stable dispersed systems are obtained, classified as emulsions based on their optical appearance and dispersed droplet size. The dynamic viscosity measured as a function of shear rate indicated non-Newtonian behavior with a shear-thinning response for all emulsions. An increase of water percentage led to emulsified fuels with higher viscosity levels. Finally, puffing and micro-explosion occurrence was studied by placing emulsified fuel droplets on a heated plate leading to the Leidenfrost effect. The puffing occurrence is reported for all emulsified fuels tested. A sudden puffing is noted when the water ratio is increased. Conversely, the micro-explosion phenomenon only occurred in emulsions formulated without surfactant. However, an analysis conducted on a smaller emulsion droplet showed several ejected child droplets and micro-explosion. This fact denotes a strong relationship between the emulsion droplet size, water ratio and water droplet size with the occurrence of the puffing and micro-explosion phenomena.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK, ZRSKP
Vegetable oils and animal fats represent promising alternatives to diesel engine fuel because they can be obtained from different feedstocks and renewable sources; also their properties are close to ...diesel fuel. The direct use of these biofuels as a diesel engine fuel can cause several problems in engine performance and emissions. In order to obtain a more engine-friendly fuel, it is necessary to change the biofuels’ properties for which different methods have been used. One of the possibilities is using emulsification techniques in order to obtain emulsified biofuels (emulsions or microemulsions); through this method it is possible to lower viscosity and improve the atomization. However, emulsification techniques applied to vegetable oils and animal fats have not been studied thoroughly. For this reason, this paper presents an overview on the formulation and characterization of the emulsified biofuels using vegetable oils and animal fats, as well as the main experimental results reported about its use as a diesel engine fuel in the scientific literature.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK
•Discussion of various issues with regard to formulation of emulsions containing FAD.•Stable emulsions were produced using FAD, diesel fuel and a mixture of surfactants.•The effect of emulsions on ...engine performance and exhaust emissions were studied.•Emulsions containing FAD and water lead to higher BSFC and delayed start of combustion.•Emulsions were found as an effective way to reduce the nitrogen oxides emissions.
In this contribution an experimental investigation concerning the effect of emulsified fuels based on fatty acid distillates (FAD) on a single cylinder diesel engine performance and exhaust emissions was investigated. The single cylinder diesel engine assessment was conducted under selected test conditions, fixing the engine speed and varying the load. Emulsified fuels were formulated using blends of fatty acid distillates in diesel fuel as continuous phase, as well as deionized water as dispersed phase and Nonyl phenol with 8mol of ethylene oxide as surfactant. Over these conditions the brake specific fuel consumption (BSFC), brake thermal efficiency (BTE), ignition delay (ID), rate of heat release (ROHR), cumulative heat release, nitrogen oxides (NOx), carbon monoxide (CO) and unburned hydrocarbons (HC) were analyzed. The results indicate that the use of emulsified fuels produce increases in the specific fuel consumption and decreases in the brake thermal efficiency for emulsions compared to diesel fuel and a blend of 30% FAD in diesel. On the other hand, later starts of combustion and retarded ROHR for emulsified fuels compared to diesel fuel and a blend of 30% FAD in diesel were obtained. Further, lower NOx and higher HC and CO emissions for emulsified fuels were reported.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The emulsification of water in vegetable oils is one of the most promising techniques reported in order to reach an engine-friendly fuel with proper physicochemical properties, allowing improvements ...in the atomization process and exhaust emissions. For this reason, the scope of this investigation is to formulate and characterize emulsified fuels using different continuous phases, as well as to analyze the influence of the increase of the surfactant concentration on the system stability. The emulsified systems were formulated using ultrasonic equipment and consisted of continuous phase rapeseed oil and fatty acid distillates mixed with diesel fuel. Additional components such as deionized water, ethanol and octanol, as well as sorbitan monooleate and polyoxyethylene sorbitan monooleate as surfactant, were used. The formulated dispersed systems were covered under different experimental factors and summarized in ternary diagrams. Several stable dispersed systems were achieved (emulsions and microemulsions); but only with the introduction of diesel fuel to the formulations, proper viscosity values were achieved. An increase of the viscosity with increasing the amount of water was noted. The water droplets sizes of emulsified rapeseed oil were smaller than in the emulsified fatty acid distillates. Finally, an increase of surfactant percentage in the emulsification process improved the dispersed systems’ stability and their optical appearance, whereas also slight differences in density, viscosity and surface tension values were noted.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK, ZRSKP
The production of biodiesel from fatty acid distillates (FAD) is a technically viable route but the assessment of engine performance and environmental impact are non-well researched issues. The scope ...of this contribution is to develop a characterization of the FAD obtained as a waste product from the vegetable oil refining industry and to evaluate the biodiesel performance and exhaust emissions on a diesel engine. A physicochemical characterization is also developed. The gas chromatography results show the fatty acids profile, indicating 50.56% of linoleic acid. Acidity level indicated that the FAD must be converted to biodiesel before its use on a diesel engine. The conversion of FAD to biodiesel reaches 92% yield. Combustion of biodiesel from FAD shows 80% increase in the specific fuel consumption and 5.6% in NOx, shorter ignition delay and hydrocarbons and CO reductions in 22% and 46%, respectively. The results demonstrate the viability to produce biofuels from FAD, which also leads to a reduction of environmental pollutants.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
The aim of this research is to identify and quantify the categories which have the largest environmental impact in the biodiesel production process from Jatropha curcas L oil. The Jatropha curcas L ...is selected due to its availability in Cuba, so 400 L/d was defined as a functional unit. The valorization analysis was conducted taking into account the conventional Jatropha curcas L oil production. The analysis is conducted based on several factors such as the use of synthetic fertilizers, pesticides, and agriculture wastes. The activities of agriculture and industrial stages are shown. The Life Cycle Assessment is addressed according to the ISO 14040 series, by using the Ecoinvent database 2003 and the Eco-indicator 99 methodology. Based on the obtained results, the environmental performance of the production of biodiesel from Jatropha curcas L oil has a good environmental behavior. The agriculture stage shows the greatest impact due to land use and fossil fuel depletion. In addition, electricity has the highest impact due to respiratory effects from the emission of tiny material particles into the atmosphere.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
Data on the rapid, elemental and calorimetric analysis, such as ash melting behaviour and thermogravimetric profiles of six Cuban biomass feedstock are shown, in order to assess their potential for ...bioenergy production. The studied biomasses are Jatropha curcas husk, Moringa oleifera husk, Dichrostachys cinerea, Ulva lactuca, Chaetomorpha gracilis and Sargassum fluitants. Seed, kernels or stems and algae were characterized by weight. Sample preparation and tests were established according to referenced German standards with particle size <75 mm. In addition, thermogravimetric analyses have been performed at 10 °C/min in Argon atmosphere. Data in the paper are shown in Tables and Graphs. The data represent valuable information for simulation or further implementation of gasification or pyrolysis processes using these biomasses.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
Data in this paper covers in-cylinder pressure and volume, crank angle degrees as time magnitude, first derivate of in-cylinder pressure, admission pressure and injection pressure in a diesel engine ...fuelled with biodiesel. This data brings additional information such as ignition delay and rate of heat released. As condensed information, some graphs were obtained and are into the database such as in-cylinder vs. CAD, first derivate of in-cylinder pressure vs. CAD and ROHR vs. CAD. The data shows the measurements of the cylinder pressure behaviour of biodiesel from two different sources, which are both of interest of bioenergy industry at local scenarios (Jatropha curcas and Fatty Acid Distillates). Data in the paper are shown in Tables and Graphs. Through this data, a more accurate approach to engines performance and combustion can be reach, enhancing combustion efficiency and understanding of differences with standard diesel fuel.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
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