Ethyl levulinate: A potential bio-based diluent for biodiesel which improves cold flow properties

Biodiesel, defined as mono-alkyl esters of long-chain fatty acids derived from vegetable oils or animal fats, is an attractive renewable fuel alternative to conventional petroleum diesel fuel. Biodiesel produced from oils such as cottonseed oil and poultry fats suffer from extremely poor cold flow properties because of their high saturated fatty acid content. In the current study, Ethyl Levulinate (ethyl 4-oxopentanoate) was investigated as a novel, bio-based cold flow improver for use in biodiesel fuels. The cloud (CP), pour (PP), and cold filter plugging points (CFPP) of biodiesel fuels prepared from cottonseed oil and poultry fat were improved upon addition of ethyl levulinate at 2.5, 5.0, 10.0, and 20.0% (vol). Reductions of 4-5 °C in CP, 3-4 °C in PP and 3 °C in CFPP were observed at 20 vol % ethyl levulinate. The influence of ethyl levulinate on acid value, induction period, kinematic viscosity and flash point was determined. The kinematic viscosities and flash points decreased with increasing content of ethyl levulinate. All samples (≤15 vol % ethyl levulinate) satisfied the ASTM D6751 limit with respect to flash point, but none of the 20 vol % blends were acceptable when compared to the higher EN 14214 specification. Acid value and oxidative stability were essentially unchanged upon addition of ethyl levulinate. In summary, ethyl levulinate appears acceptable as a diluent for biodiesel fuels with high saturated fatty acid content.     

Analysis of blended fuel properties and engine performance with palm biodiesel–diesel blended fuel

Depleting fossil fuel sources accompanied by continuously growing energy demands lead to increased interest in alternative energy sources. Blended biodiesel–diesel fuel has been approved as a commercial fuel at a low blending ratio. However, problems related to fuel properties are persistent at high blending ratios. Hence, in this study, the feasibility of biodiesel produced from palm oil was investigated. Characterization of blended fuel properties with increasing palm biodiesel ratio is conducted to evaluate engine performance test results. The qualifying of blended fuel properties was used to indicate the maximum blending ratio suitable for use in unmodified diesel engines according to the blended fuel standard ASTM D7467. The property test results revealed that blended fuel properties meet blended fuel standard requirements at up to 30% palm oil biodiesel. Furthermore, blending is efficient for reduction of the pour point from 14 °C for unblended biodiesel to less than 0 °C at a 30% biodiesel blending ratio. However, the energy content reduces by about 1.42% for each 10% increment of biodiesel. Engine test results demonstrated that there was no statistically significant difference for engine brake thermal efficiency among tested blended fuels compared to mineral diesel, and the lowest engine cyclic variation was achieved with blended fuel B30.     

Tertiary fatty amides as diesel fuel substitutes

This paper presents experimental results regarding the impact of adding different tertiary amides of fatty acids to mineral diesel fuel; an assessment of the behaviour of these compounds as possible diesel fuel extenders is also included. Measurements of cetane number, cold flow properties (cloud point, pour point and CFPP), density, kinematic viscosity, flash point and distillation temperatures are reported, while initial experiments concerning the effects on particulate emissions are also described. Most of the examined tertiary fatty amides esters have very good performance and they can be easily prepared from fatty acids (biomass). Such compounds or their blends could be used as mineral diesel fuel or even fatty acid methylesters (FAME, biodiesel) substitutes or extenders. Copyright © 2000 John Wiley & Sons, Ltd.     

Effect of ethanol addition on the properties of Jatropha ethyl ester

Fossil fuels are available in limited quantity and may extinct in future. Moreover, pollutant emission from diesel engines affects the ecological systems. Biodiesel, derived from vegetable oil, is a renewable and green source of fuel. In this study, biodiesel produced from base catalyzed transesterification was blended with different diesel volumes. The diesel–biodiesel blends showed varied flash point (168–42°C), viscosity (4.34–3.31 mm²/s), density (0.872–0.8351 g/cm³), acid value (0.3–0.4 mg KOH/g), and cetane number (51.6–49.5). The results showed that alcohol addition helped in reducing viscosity and density of biodiesel by almost half. These provide explanation on engine performance, combustion, and emission characteristics.     

Experimental study and empirical correlation development of fuel properties of waste cooking palm biodiesel and its diesel blends at elevated temperatures

In this experimental work, the density, dynamic viscosity and higher heating value of methyl ester based waste cooking palm-biodiesel oil (WMEPB) was investigated under varying temperature and blend ratio condition with No. 2 diesel fuel. The transesterified fatty acid methyl ester of palm vegetable oil collected from local food and beverage shops was used as neat biodiesel. Four different fuel blends (20%, 40%, 60% and 80% by volume mixing with base diesel) were studied along with base No. 2 diesel fuel and pure biodiesel. Tests for dynamic viscosity and density were performed in the temperature range 0–130 °C for each fuel sample whereas the higher heating values were determined at 25 °C room temperature condition. It is found that pure biodiesel has the highest density and dynamic viscosity at a given temperature whereas it exhibits lowest combustion heating value among the six fuels. Moreover, the density for each fuel sample decreases linearly with the increase in temperature. On the other hand, the dynamic viscosity decreases exponentially with the temperature for each fuel sample. In addition, based on the experimental results, regression correlations have been proposed for the density, dynamic viscosity, and higher heating value of the fuels. Subsequently, comprehensive error analyses of these proposed correlations were performed. In particular, the correlation for density and dynamic viscosity were respectively compared with Kay's mixing rule and Grunberg-Nissan mixing rule theory in order to validate their applicability. It is found that density correlations predicted within ±0.3% average error band. And, as high as 72.2% of the dynamic viscosity data were in the range of ±5% average error while the remaining data fell within ±10% error range. And finally, through a comparative study with the available fuel property results of fresh methyl ester palm biodiesel, it is found that available existing correlations derived from fresh palm biodiesel studies can not accurately predict the fuel properties of same waste biodiesel and its blends with diesel.     

Fuel properties of biodiesel produced from selected plant kernel oils indigenous to Botswana: A comparative analysis

Fuel characteristics of biodiesel derived from kernel oils of Sclerocarya birrea, Tylosema esculentum, Schiziophyton rautanenii and Jatropha curcas plants were investigated in comparison with petroleum diesel. The fuel properties under review include flash point, cloud point, kinematic viscosity, density, calorific value, acid value, and free fatty acids. These were determined and discussed in light of major biodiesel standards such as ASTM D 6751 (American Society for Testing and Materials) and EN 14214 (European standards). The best biofuel in terms of cold flow properties was S. rautanenii, with a cloud point of 0 °C and a pour point of −5 °C. The good cold flow properties demonstrate operational viability during the cold season. The heating values of S. birrea and S. rautanenii biodiesel fuels were found to be 9.2% and 10.3% lower than that of petroleum diesel while those of T. esculentum and J. curcas were both 9.7% lower. Other fuel properties analysed demonstrate that biodiesel fuels produced from kernel oils of S. birrea, T. esculentum, S. rautanenii and J. curcas plants have properties that are comparable to, and in some cases better than, those of petroleum diesel. The results of this study indicate the feasibility of producing quality biodiesel fuel from indigenous seed oils found in Botswana. A balanced allocation of resources however needs to be established to ensure that the cultivation of these oil-bearing plants does not compete with the cultivation of food crops.     

Particle-bound PAH emissions from a waste glycerine-derived fuel blend in a typical automotive diesel engine

Polynuclear or polycyclic aromatic hydrocarbons (PAH) are known to be one of the most dangerous types of compounds of their class due to their carcinogenic potential. Some atmospheric PAH are measured and regulated to quantify the air quality. However, in order to better understand the presence of these compounds in the atmosphere it is crucial to study the PAH emissions sources. In this work, we analyze the particulate-bound PAH emissions, as well as their carcinogenic potential, from a typical baseline diesel engine using a promising alternative fuel obtained from the glycerol surplus in the biodiesel production industry. This advanced biofuel (Mo.bio) is a ternary mixture of residual glycerine-derived fuel (FAGE), a conventional fatty acid methyl ester (FAME) and a diesel fuel. Two operating conditions representative of the conflicting scenarios when studying polluting emissions (speeds of 50 km/h and 70 km/h typical of urban and extra-urban driving conditions) are used. In addition, with the purpose of deepening the understanding of the behavior of this new fuel, tests are carried out modifying the Exhaust Gas Recirculation (EGR) ratio. The PAH samples are collected before the aftertreatment systems in order to assess the possible formation of PAH with this type of fuel and to evaluate the options of the aftertreatment devices. Sampling is carried out using fiber-glass filters, extracting the trapped PAH using Soxhlet method. The analytical procedure (liquid chromatography with fluorescence detection) allows to appreciate differences between the different fuels and modes of operation, observing higher emissions of benzo[a]pyrene (BaP) and dibenz[a,h]anthracene (DahA) for the diesel fuel than for the mixture containing residual glycerine-derived fuel. Therefore, it is concluded that the fossil fuel has a larger carcinogenic potential in these conditions, and that the Mo.Bio fuel may possibly expand the EGR ratio range without increasing the requirement of the particle filter.     

A cycle simulation model for predicting the performance of a diesel engine fuelled by diesel and biodiesel blends

Among the alternative fuels, biodiesel and its blends are considered suitable and the most promising fuel for diesel engine. The properties of biodiesel are found similar to that of diesel. Many researchers have experimentally evaluated the performance characteristics of conventional diesel engines fuelled by biodiesel and its blends. However, experiments require enormous effort, money and time. Hence, a cycle simulation model incorporating a thermodynamic based single zone combustion model is developed to predict the performance of diesel engine. The effect of engine speed and compression ratio on brake power and brake thermal efficiency is analysed through the model. The fuel considered for the analysis are diesel, 20%, 40%, 60% blending of diesel and biodiesel derived from Karanja oil (Pongamia Glabra). The model predicts similar performance with diesel, 20% and 40% blending. However, with 60% blending, it reveals better performance in terms of brake power and brake thermal efficiency.     

Assessment of energy performance and air pollutant emissions in a diesel engine generator fueled with water-containing ethanol–biodiesel–diesel blend of fuels

Biomass based oxygenated fuels have been identified as possible replacement of fossil fuel due to pollutant emission reduction and decrease in over-reliance on fossil fuel energy. In this study, 4 v% water-containing ethanol was mixed with (65–90%) diesel using (5–30%) biodiesel (BD) and 1 v% butanol as stabilizer and co-solvent respectively. The fuels were tested against those of biodiesel–diesel fuel blends to investigate the effect of addition of water-containing ethanol for their energy efficiencies and pollutant emissions in a diesel-fueled engine generator. Experimental results indicated that the fuel blend mix containing 4 v% of water-containing ethanol, 1 v% butanol and 5–30 v% of biodiesel yielded stable blends after 30 days standing. BD1041 blend of fuel, which composed of 10 v% biodiesel, 4 v% of water-containing ethanol and 1 v% butanol demonstrated −0.45 to 1.6% increase in brake-specific fuel consumption (BSFC, mL kW⁻¹ h⁻¹) as compared to conventional diesel. The better engine performance of BD1041 was as a result of complete combustion, and lower reaction temperature based on the water cooling effect, which reduced emissions to 2.8–6.0% for NO_x, 12.6–23.7% particulate matter (PM), 20.4–23.8% total polycyclic aromatic hydrocarbons (PAHs), and 30.8–42.9% total BaPeq between idle mode and 3.2 kW power output of the diesel engine generator. The study indicated that blending diesel with water-containing ethanol could achieve the goal of more green sustainability.     

Influence of blending ratio on the physicochemical properties of safflower oil methyl ester-safflower oil,safflower oil methyl ester-diesel and safflower oil-diesel

In this study, the methyl ester production and characterization from safflower oil (SO) was examined. The seed were collected from Yozgat-Turkey and SO was obtained from safflower seeds using screw press. SO was transesterified with methanol and NaOH to obtain safflower oil methyl ester (SOME). SO and SOME show high amounts of linoleic acid of 62.29 and 61.17%, respectively. This result in better low temperature properties of SOME like cloud point (CP) of −5 °C, pour point (PP) of −14 °C, freezing point (FP) of −16 °C and cold filter plugging point (CFPP) of −9 °C. Cold flow properties of SOME demonstrate its operational viability during the cold weather conditions and also it exhibited excellent transportation safety with flash point of 171 °C. It has been found that fuel properties of SOME indicate that SO can be considered as a future biodiesel source. Furthermore, viscosity, density, higher heating value (HHV), flash point, water content, pH, copper strip corrosion, CP, PP, FP and CFPP of SOME-SO, SOME-Euro Diesel(ED) and SO-ED blends have been investigated and discussed in the light of biodiesel standards. The effects of temperature and fraction on density and viscosity of blends were studied and constants of these correlations vary depending on the type of blend.     

Corrosion behavior of ASTM 1045 mild steel in palm biodiesel

Corrosive characteristics of biodiesel are important for long-term durability of engine parts. The effect of palm biodiesel on corrosion properties of ASTM 1045 mild steel was studied and compared with that of commercial diesel fuel (0# diesel). Static immersion tests were carried out at different temperatures (27, 50 and 80 °C) for 30, 60 and 120 d. The morphology and composition of corrosion products were characterized by SEM, FT-IR, XRD and XPS. The total acid number was used to investigate the change in acidity of fuel upon exposure. It was found that palm biodiesel is more corrosive than 0# diesel. Temperature and exposure time have critical impact on metal corrosion and degradation of fuels.     

Comparison of performance characteristics of agricultural tractor diesel engine operating on home and industrially produced biodiesel

Owing to unstable diesel fuel prices in the world market, many farmers have been looking for alternative fuels. Vegetable oils are one of the alternatives, which can be used as fuel in diesel engines either in the form of straight vegetable oil or in the form of biodiesel. This study aims to present experimental data by utilization of home and industrial biodiesel as fuel in an agricultural tractor diesel engine. The home biodiesel production was made from different vegetable oils (crude rapeseed, edible sunflower and waste oil) with the process of one‐stage‐based catalyzed transesterification. A commercially available agricultural tractor ZETOR 7745 was employed. Measurements were taken on the power take‐off shaft by electrical dynamometer FROMENT XT200. According to the results, agricultural tractor diesel engine operating on home biodiesel fuels had better performance characteristics related to industrially produced biodiesel and similar to conventional diesel fuel. Copyright © 2009 John Wiley & Sons, Ltd.     

Characterization of beef tallow biodiesel and their mixtures with soybean biodiesel and mineral diesel fuel

Tallow is a raw material for biodiesel production that, due to their highly centralized generation in slaughter/processing facilities and historically low prices, may have energy, environmental, and economic advantages that could be exploited. However beef tallow biodiesel have unfavorable properties due the presence of high concentration of saturated fatty esters. One way to overcome these inconveniences is using blending procedures. In this way, blends of beef tallow biodiesel with soybean biodiesel and with conventional mineral diesel fuel were prepared and the quality of the mixtures was monitored with the purpose to study ideal proportions of the fuels. By measurement of the viscosity, density, cold filter plugging point, and flash point, it was demonstrated that tallow biodiesel can be blended with both mineral diesel and soybean biodiesel to improve the characteristics of the blend fuels, over that of the tallow.     

非直喷式增压柴油机燃用生物柴油的性能与排放特性

研究了非直喷式增压柴油机燃用柴油一生物柴油混合燃料的性能和排放特性。未对原机作任何调整和改动,研究了不同生物柴油掺混比例的混合燃料对功率、油耗、烟度和NOx排放的影响。结果表明：非直喷式柴油机燃用生物柴油后柴油机功率略有下降,油耗有所上升,烟度大幅下降,NOx排放增加明显。油耗、烟度和NOx的变化均与生物柴油掺混比例呈线性关系,合适的生物柴油掺混比例即可以保持柴油机的性能,又可有效地降低碳烟排放,且不引起NOx排放的显著变化。对于该增压柴油机,掺混生物柴油对外特性下的排放影响最大,影响最小的为标定转速下的负荷特性。不论是全负荷还是部分负荷,燃用生物柴油时低速下的烟度降低和NOx上升幅度均比高速时大,而同转速下高负荷时烟度降低和NOx上升更为明显。     

Improved biodiesel manufacture at low temperature and short reaction time

Biodiesel, which is derived from oil/fat by transesterification with alcohol, has attracted considerable attention over the past decades due to its ability to subsidise fossil fuel derived energy as a renewable and carbon neutral fuel. Several approaches for biodiesel fuel production have been developed, among which transesterification using a catalyst gives high yields of methyl ester. This method has therefore been widely utilized for biodiesel production in a number of countries. In this study, a Downflow Liquid Contactor Reactor (DLCR) has been used for the liquid–liquid transesterification reaction of sunflower oil with alcohol with extraordinary results. The reactor provides great potential for chemical reactions, which are normally limited by mass transfer and possesses a number of distinctive advantages over conventional multiphase reactors. Inside the reactor a high velocity liquid jet stream is produced which generates powerful shear and energy, causing vigorous agitation in the upper part of the reactor. The high mixing intensity in the DLCR enabled the manufacture of biodiesel to European Standard EN14214 (ester content 96.5%) in 2.5 min at 40 °C with 0.43 wt.% alkali catalyst and alcohol to oil molar ratio of 4.5 to 1.0. The separation of FAME from glycerol is done by gravity settling only without water washing. The effect of the alcohol type (methanol, ethanol) on biodiesel yield was also investigated. The process offers the advantage of continuous large scale production with limited reactor volume.     

Combined impact of varying biogas mass flow rate and rice bran methyl esters blended with diesel on a dual-fuel engine

ABSTRACT

For fetching day-to-day energy needs, current energy requirement majorly depends on fossil fuels. But ambiguous matter like abating petroleum products and expanding air pollution has enforced the experts to strive for another fuel which can be used as an alternative or reduce the applications of fossil fuels. Considering the issues, the main objective of the present study is to find the feasibility by using blends of rice bran oil biodiesel and diesel which are used as pilot fuels by blending 10% and 20% biodiesel in fossil diesel and biogas, introduced as gaseous fuel by varying its mass flow rate in a dual-fuel engine mode. An experimentation study was carried out to find the performance and emission parameters of the engine relative to pure diesel. The results were very much similar to the majority of researchers who used biodiesel and gaseous fuels in a dual-fuel engine. Brake specific fuel consumption (BSFC) of the engine was noticed to have increased, while brake thermal efficiency was on the lower side in dual fuel mode in comparison with regular diesel. In relation with conventional diesel, it was noticed that combined effect of rice bran methyl esters and varying mass flow rate of biogas showed a decrement in NO _x and smoke emissions, whereas HC and CO exhalations were on higher side when biogas and biodiesel were utilized collectively in dual-fuel engine. Hence, it was concluded that combination of blends of biodiesel and diesel and introduction of biogas in the engine can be a promising combination which can be used as a substitute fuel for addressing future energy needs.     

Review of biodiesel composition, properties, and specifications

Biodiesel is a renewable transportation fuel consisting of fatty acid methyl esters (FAME), generally produced by transesterification of vegetable oils and animal fats. In this review, the fatty acid (FA) profiles of 12 common biodiesel feedstocks were summarized. Considerable compositional variability exists across the range of feedstocks. For example, coconut, palm and tallow contain high amounts of saturated FA; while corn, rapeseed, safflower, soy, and sunflower are dominated by unsaturated FA. Much less information is available regarding the FA profiles of algal lipids that could serve as biodiesel feedstocks. However, some algal species contain considerably higher levels of poly-unsaturated FA than is typically found in vegetable oils.Differences in chemical and physical properties among biodiesel fuels can be explained largely by the fuels’ FA profiles. Two features that are especially influential are the size distribution and the degree of unsaturation within the FA structures. For the 12 biodiesel types reviewed here, it was shown that several fuel properties - including viscosity, specific gravity, cetane number, iodine value, and low temperature performance metrics - are highly correlated with the average unsaturation of the FAME profiles. Due to opposing effects of certain FAME structural features, it is not possible to define a single composition that is optimum with respect to all important fuel properties. However, to ensure satisfactory in-use performance with respect to low temperature operability and oxidative stability, biodiesel should contain relatively low concentrations of both long-chain saturated FAME and poly-unsaturated FAME.     

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

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 mm² s^?1, whereas those of vegetable oil methyl esters between 3.59 and 4.63 mm² 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.     

Development of low‐temperature properties on biodiesel fuel: a review

The use of biodiesel as a diesel fuel alternative is rapidly increasing. An important aspect of applying this alternative is the transportation and application in cold weather. In this article, different kinds of methods and technologies were briefly reviewed to improve the low‐temperature properties of biodiesel. The compositions of fatty acids would be effectively changed by choosing available material with high content of unsaturated fatty acids or by reducing saturated fatty acids via winterization process. Branched alcohols can be used to change biodiesel structures that improve the low‐temperature properties. As a technically feasible method, there is still a constant demand to search cost‐effective raw materials for economic branched alcohols production. In order to enhance the impact of crystal morphology and decrease freezing point, the blending chemical additives and petroleum fuels would be a promising method that have been widely used. Besides, other treatments such as epoxidation, hydroisomerization, and ozonization were also discussed. However, each method applied for improving low‐temperature properties of biodiesel should be effective and economical so that the biodiesel would continue to compete with fossil and other renewable fuels for market share. Copyright © 2015 John Wiley & Sons, Ltd.     

Study on the spray characteristics of methyl esters from waste cooking oil at elevated temperature

In Taiwan, millions of tons of waste cooking oil are produced each year, and less than 20% of it, about 150,000 ton/a, is reclaimed and reused. Most waste oil is flushed down the drain. Utilizing waste cooking oil to make biodiesel not only reduces engine exhaust gas pollution, but also replaces food-derived fuels, and reduces ecologic river pollution. This study employed two-stage transesterification to lower the high viscosity of waste oil, utilized emulsion to reduce the methyl ester NOx pollution, and used methanol to enhance the stability and viscosity of emulsified fuel. To further analyze spray characteristics of fuels, this experiment built a constant volume bomb under high temperature, used high speed photography to analyze spray tip penetration, spray angle, and the Sauter mean diameter (SMD) of fuel droplets, and compared the results with fossil diesel. The experimental results suggested that, two-stage transesterification can significantly lower waste oil viscosity to that which is close to fossil diesel viscosity. At a temperature above 300 °C, waste cooking oil methyl esters had a water content of 20%, spray droplet characteristics were significantly improved, and NOx emission dropped significantly. The optimal fuel ratio suggested in this experiment was waste cooking oil methyl ester 74.5%, methanol 5%, water 20%, and composite surfactant Span–Tween 0.5%.