Biodiesel production from inedible animal tallow and an experimental investigation of its use as alternative fuel in a direct injection diesel engine

In this study, a substitute fuel for diesel engines was produced from inedible animal tallow and its usability was investigated as pure biodiesel and its blends with petroleum diesel fuel in a diesel engine. Tallow methyl ester as biodiesel fuel was prepared by base-catalyzed transesterification of the fat with methanol in the presence of NaOH as catalyst. Fuel properties of methyl ester, diesel fuel and blends of them (5%, 20% and 50% by volume) were determined. Viscosity and density of fatty acid methyl ester have been found to meet ASTM D6751 and EN 14214 specifications. Viscosity and density of tallow methyl esters are found to be very close to that of diesel. The calorific value of biodiesel is found to be slightly lower than that of diesel. An experimental study was carried out in order to investigate of its usability as alternative fuel of tallow methyl ester in a direct injection diesel engine. It was observed that the addition of biodiesel to the diesel fuel decreases the effective efficiency of engine and increases the specific fuel consumption. This is due to the lower heating value of biodiesel compared to diesel fuel. However, the effective engine power was comparable by biodiesel compared with diesel fuel. Emissions of carbon monoxide (CO), oxides of nitrogen (NO_x), sulphur dioxide (SO₂) and smoke opacity were reduced around 15%, 38.5%, 72.7% and 56.8%, respectively, in case of tallow methyl esters (B100) compared to diesel fuel. Besides, the lowest CO, NO_x emissions and the highest exhaust temperature were obtained for B20 among all other fuels. The reductions in exhaust emissions made tallow methyl esters and its blends, especially B20 a suitable alternative fuel for diesel and thus could help in controlling air pollution. Based on this study, animal tallow methyl esters and its blends with petroleum diesel fuel can be used a substitute for diesel in direct injection diesel engines without any engine modification.     

Combustion performance and emissions of ethyl ester of a waste vegetable oil in a water-cooled furnace

Food consumption around the world produces large amounts of waste vegetable oils and fats that, in many world regions, are disposed of in harmful ways. Consequently, this study intended to investigate the feasibility of utilizing this renewable and low cost fuel raw material as a diesel fuel replacement in small-scale applications such as in residential heating boilers. Specifically, the study examined the aspects of combustion performance and emissions of the ethyl ester of used palm oil (biodiesel) relative to the baseline diesel fuel in a water-cooled furnace. The combustion efficiency, η_c, and exhaust temperature, T_exh, as well as the common pollutants and emissions were tested over a wide range of air/fuel ratio ranging from very lean to very rich (10:1–20:1). All tests were conducted at two different energy inputs for both fuels. The findings showed that, at the lower energy rate used, biodiesel burned more efficiently with higher combustion efficiency and exhaust temperature of, respectively, 66% and 600 °C compared to 56% and 560 °C for the diesel fuel. At the higher energy input, biodiesel combustion performance deteriorated and was inferior to diesel fuel due to its high viscosity, density and low volatility. As for emissions, biodiesel emitted less pollutants at both energy levels over the whole range of A/F ratio considered.     

Impact of alternative fuel properties on fuel spray behavior and atomization

In order to verify and solve the problem of NOx and PM emissions, it is necessary to directly observe the internal combustion chamber of a diesel engine. Many studies have been performed in recent years to verify the macroscopic and microscopic behavior of the injected fuel spray because observing it is not easy due to the difficulties of the experiment. Researchers have investigated the spray characteristics for various diesel injector nozzles over a wide range of temperatures and pressure, but there is lack of evaluation for the spray characteristics for biodiesel. At a time when rapid rise of fuel prices and depleting hydrocarbon resources of the world have forced us to look for alternative fuels biodiesel produced by transesterification of non-edible vegetable oils is promising to be an important additive/substitute to petro diesel. Biodiesel being an oxygenated and sulfur-free fuel leads to more complete combustion and lower emissions. But, the energy content or net calorific value of biodiesel is less than that of diesel fuel; also it has higher viscosity and density, than diesel fuel. A considerable improvement in these properties can be obtained by mixing diesel and biodiesel and then using the blends. Biodiesel and biodiesel/petro diesel blends, with their higher lubricity levels, are increasingly being utilized as an alternative. Present paper analyzed the correlation of injection parameters that will affect the spray characteristics of biodiesel. Observations for analyzing the effect of injection parameters on spray cone angle, break up length and fuel penetration were made. Finally the performance and emissions tests were studied. Atomization and vaporization of fuel are greatly influenced by viscosity and density of fuel and these properties are temperature dependent. Thus fuel inlet temperature plays a very important role in fuel atomization process. At higher temperature viscosity of fuel decreases which enhances the atomization of biofuels.     

Assessment of basic properties and thermal analysis of hybrid biofuel blend

Among the alternative fuels, vegetable oil is seen as a potential source of energy due to its readily available variety of sources and its certain physical properties that are comparable to those of diesel fuels. However, higher contents of triglyceride in vegetable oil contribute to higher viscosity and density that is affecting the inferior engine performance and emissions. The key properties, such as viscosity, density, and calorific value (CV), have a significant effect on fuel atomization, fuel combustion, and exhaust emissions. In this study, refined palm oil (RPO) was blended with a newly introduced novel biofuel, Melaleuca cajuputi oil (MCO), in order to reduce the viscosity and density and enhance blend properties. This blend is analyzed and compared with RPO–diesel and RPO–ethanol blends in terms of viscosity, CV, and density. These hybrid binary biofuel (HBB) blends were prepared on the volumetric basis of 10%, 20%, 30%, and 50% of MCO, ethanol, and diesel with RPO. The basic fuel properties and the correlation of temperature–viscosity–blend ratio were analyzed. The results showed that the MCO has comparable key properties to those of diesel fuels. The viscosity and density of HBB decrease as the fraction of MCO/ethanol/diesel increases in the blend. The higher the fraction of MCO/diesel in the blend, the higher is the CV observed. Notably, the viscosity of neat RPO and its blends is strongly influenced by temperature variations. The combination of blend technique and preheating had a substantial effect in reducing the viscosity and density of the HBB. Remarkably, the blend of MCO–RPO has the potential to highly considered as a new source of biofuel.     

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.     

Performance evaluation of a diesel engine fueled with methyl ester of castor seed oil

In this investigation, castor methyl ester (CME) was prepared by transesterification using potassium hydroxide (KOH) as catalyst and was used in four stroke, single cylinder variable compression ratio type diesel engine. Tests were carried out at a rated speed of 1500 rpm at different loads. Straight vegetable oils pose operational and durability problems when subjected to long term usages in diesel engines. These problems are attributed to high viscosity, low volatility and polyunsaturated character of vegetable oils. The process of transesterification is found to be an effective method of reducing vegetable oil viscosity and eliminating operational and durability problems. The important properties of methyl ester of castor seed oil are compared with diesel fuel. The engine performance was analysed with different blends of biodiesel and was compared with mineral diesel. It was concluded that the lower blends of biodiesel increased the break thermal efficiency and reduced the fuel consumption. The exhaust gas temperature increased with increasing biodiesel concentration. The results proved that the use of biodiesel (produced from castor seed oil) in compression ignition engine is a viable alternative to diesel.     

A comparative evaluation of compression ignition engine characteristics using methyl and ethyl esters of Karanja oil

This paper investigates the scope of utilizing biodiesel developed from both through the methyl as well as ethyl alcohol route (methyl and ethyl ester) from Karanja oil as an alternative diesel fuel. The major problem of using neat Karanja oil as a fuel in a compression ignition engine arises due to its very high viscosity. Transesterification with alcohols reduces the viscosity of the oil and other properties have been evaluated to be comparable with those of diesel. In the present work, methyl and ethyl esters of Karanja oil were prepared by transesterification using both methanol and ethanol. The physical and chemical properties of ethyl esters were comparable with that of methyl esters. However, viscosity of ethyl esters was slightly higher than that of methyl esters. Cold flow properties of ethyl esters were better than those of methyl esters. Performance and exhaust emission characteristics of the engine were determined using petrodiesel as the baseline fuel and several blends of diesel and biodiesel as test fuels. Results show that methyl esters produced slightly higher power than ethyl esters. Exhaust emissions of both esters were almost identical. These studies show that both methyl and ethyl esters of Karanja oil can be used as a fuel in compression ignition engine without any engine modification.     

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%.     

压燃发动机燃用不同原料生物柴油的燃烧与排放特性

利用KIVA3数值模拟研究柴油以及三种生物柴油(大豆油甲酯、棕榈油甲酯、麻疯油甲酯)对压燃发动机燃烧和排放性能的影响。数值计算结果表明:生物柴油在燃烧初始阶段与柴油燃烧特性基本一致,燃烧中后期,生物柴油的平均缸温低于柴油,其中麻疯油甲酯最为明显;生物柴油碳烟和CO生成量明显低于柴油。生物柴油虽然缸内氧含量比柴油高,但由于受缸温的影响,NOx排放比柴油低,而麻疯油甲酯在三种生物柴油中NOx排放最低。     

Comparison of performance and emissions of diesel fuel,rapeseed and soybean oil methyl esters injected at different pressures

Fuel properties of rapeseed oil and soybean oil methyl esters (e.g. density, cetane number and viscosity etc.) are similar to those of the diesel fuel. These methyl esters can be used as diesel engine fuel by mixing withy diesel fuel. In this study a comparison of diesel fuel, the rapeseed oil methyl ester and the soybean oil methyl ester was made from the engine performance and emissions point of view. The tests were carried out with a four-cylinder diesel engine for tree different injection pressures such as 250, 300 and 350 bar with each of these fuels. For the purpose of comparison, tests were also conducted at full load conditions with diesel fuel. As the result, the performance and emission values of rapeseed oil (R) and soybean oil (S) methyl esters were found to be nearly the same with those of diesel fuels (D) when injection pressure was increased to 300 bar.     

Methyl ester of peanut (Arachis hypogea L.) seed oil as a potential feedstock for biodiesel production

The peanut (Arachis hypogea L.) seed oil was extracted from the seeds of the peanut that grows in SE Anatolia of Turkey. Oil was obtained in 50 wt/wt.%, by solvent extraction. Peanut (A. hypogea L.) seed oil was investigated as an alternative feedstock for the production of a biodiesel fuel. Biodiesel was prepared from peanut by transesterification of the crude oil with methanol in the presence of NaOH as catalyst. A maximum oil to ester conversion was 89%. The viscosity of biodiesel oil is nearer to that of petroleum diesel and the calorific value is about 6% less than that of diesel. Peanut seed oil have about 8.3% less heating value than that of diesel oil due to the oxygen content in their molecules. The quality of biodiesel is most important for engine part of view and various standards have been specified to check the quality. The important properties of peanut oil and its methyl ester (biodiesel) such as density, kinematic viscosity, flash point, iodine number, neutralization number, pour point, cloud point, cetane number are found out and compared to those of no. 2 petroleum diesel, ASTM and EN biodiesel standards. The comparison shows that the methyl ester has relatively closer fuel properties to diesel than that of raw peanut seed oil.     

Performance and emission characteristics of a Kirloskar HA394 diesel engine operated on fish oil methyl esters

The high viscosity of fish oil leads to problem in pumping and spray characteristics. The inefficient mixing of fish oil with air leads to incomplete combustion. The best way to use fish oil as fuel in compression ignition (CI) engines is to convert it into biodiesel. It can be used in CI engines with very little or no engine modifications. This is because it has properties similar to mineral diesel. Combustion tests for methyl ester of fish oil and its blends with diesel fuel were performed in a kirloskar H394 DI diesel engine, to evaluate fish biodiesel as an alternative fuel for diesel engine, at constant speed of 1500 rpm under variable load conditions. The tests showed no major deviations in diesel engine's combustion as well as no significant changes in the engine performance and reduction of main noxious emissions with the exception on NO_x. Overall fish biodiesel showed good combustion properties and environmental benefits.     

Exhaust emission study on neat biodiesel and alcohol blends fueled diesel engine

In this study, neat biodiesel with octanol additive was employed in a diesel engine and its effects on engine emission were studied. The five fuels evaluated were neat palm kernal oil biodiesel, octanol blended with biodiesel by 10%, 20%, and 30% volume, and diesel. All the emissions are reduced by the addition of octanol in biodiesel in all loads owing to the higher oxygen concentration of air/fuel mixtures and improved atomization. Hence, it is concluded that the neat biodiesel and octanol blends can be employed as an alternative fuel for existing unmodified diesel engines owing to its lesser emission characteristics.     

Performance, emission and combustion characteristics of biodiesel fuelled variable compression ratio engine

Experiments has been carried out to estimate the performance, emission and combustion characteristics of a single cylinder; four stroke variable compression ratio multi fuel engine fuelled with waste cooking oil methyl ester and its blends with standard diesel. Tests has been conducted using the fuel blends of 20%, 40%, 60% and 80% biodiesel with standard diesel, with an engine speed of 1500 rpm, fixed compression ratio 21 and at different loading conditions. The performance parameters elucidated includes brake thermal efficiency, specific fuel consumption, brake power, indicated mean effective pressure, mechanical efficiency and exhaust gas temperature. The exhaust gas emission is found to contain carbon monoxide, hydrocarbon, nitrogen oxides and carbon dioxide. The results of the experiment has been compared and analyzed with standard diesel and it confirms considerable improvement in the performance parameters as well as exhaust emissions. The blends when used as fuel results in the reduction of carbon monoxide, hydrocarbon, carbon dioxide at the expense of nitrogen oxides emissions. It has found that the combustion characteristics of waste cooking oil methyl ester and its diesel blends closely followed those of standard diesel.     

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.     

Mathematical Relationships Derived from Biodiesel Fuels

Abstract

The objective of this study was to estimate mathematical relationships derived from biodiesel fuels from various vegetable oils by non-catalytic supercritical methanol and ethanol method. The vegetable oils are all extremely viscous with viscosities ranging from 10 to 20 times greater than petroleum diesel fuel. The aim of the transesterification process is to lower the viscosity of the oil. Methyl and ethyl esters as biodiesels were prepared from vegetable oils through transesterification by non-catalytic supercritical fluids. The biodiesels were characterized for their physical and main fuel properties including viscosity, density, flash point and higher heating value (HHV). The viscosities of biodiesels (3–5 mm²/s at 311 K) were much less than those of pure oils (27–54 mm²/s at 311 K), and their HHVs of approximately 40.5 MJ/kg were 10% less than those of petrodiesel fules (～45 MJ/kg). The most important variables affecting the ester yield during the transesterification reaction are molar ratio of alcohol to vegetable oil and reaction temperature. The viscosity values of vegetable oil methyl esters highly decreases after transesterification process. Compared to 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 flash point values of vegetable oil methyl esters are highly lower than those of vegetable oils. There is high regression between density and viscosity values vegetable oil methyl esters. The relationships between viscosity and flash point for vegetable oil methyl esters are considerably regular.     

Performance and emissions of a diesel tractor engine fueled with marine diesel and soybean methyl ester

Biodiesel is an alternative fuel that is cleaner than petrodiesel. Biodiesel can be used directly as fuel for a diesel engine without having to modify the engine system. It has the major advantages of having high biodegradability, excellent lubricity and no sulfur content. This paper presents the results of investigations carried out in studying the fuel properties of soybean methyl ester (SME) and its blend with marine diesel fuel from 5%, 20% and 50% blends by volume and in running a diesel engine with these fuels. The results indicate that the use of biodiesel produces lower smoke opacity (up to 74%), but higher brake specific fuel consumption (BSFC) (up to 12%) compared to marine fuel (MF). The measured carbon monoxide (CO) emissions of B5 and B100 fuels were found to be 3% and 52% lower than that of the MF, respectively.     

Using of cotton oil soapstock biodiesel–diesel fuel blends as an alternative diesel fuel

In this study, usability of cotton oil soapstock biodiesel–diesel fuel blends as an alternative fuel for diesel engines were studied. Biodiesel was produced by reacting cotton oil soapstock with methyl alcohol at determined optimum condition. The cotton oil biodiesel–diesel fuel blends were tested in a single cylinder direct injection diesel engine. Engine performances and smoke value were measured at full load condition. Torque and power output of the engine with cotton oil soapstock biodiesel–diesel fuel blends decreased by 5.8% and 6.2%, respectively. Specific fuel consumption of engine with cotton oil soapstock–diesel fuel blends increased up to 10.5%. At maximum torque speeds, smoke level of engine with blend fuels decreased up to 46.6%, depending on the amount of biodiesel. These results were compared with diesel fuel values.     

A study on the performance and emission of a diesel engine fueled with Jatropha biodiesel oil and its blends

Biodiesel either in neat form or as a mixture with diesel fuel is widely investigated to solve the twin problem of depletion of fossil fuels and environmental degradation. The main objective of the present study is to compare performance, emission and combustion characteristics of biodiesel derived from non edible Jatropha oil in a dual fuel diesel engine with base line results of diesel fuel. The performance parameters evaluated were: brake thermal efficiency, brake specific fuel consumption, power output. As a part of combustion study, in-cylinder pressure, rate of pressure rise and heat release rates were evaluated. The emission parameters such as carbon monoxide, carbon dioxide, un-burnt hydrocarbon, oxides of nitrogen and smoke opacity with the different fuels were also measured and compared with base line results. The different properties of Jatropha oil after transestrification were within acceptable limits of standards as set by many countries. The brake thermal efficiency of Jatropha methyl ester and its blends with diesel were lower than diesel and brake specific energy consumption was found to be higher. However, HC, CO and CO₂ and smoke were found to be lower with Jatropha biodiesel fuel. NO_x emissions on Jatropha biodiesel and its blend were higher than Diesel. The results from the experiments suggest that biodiesel derived from non edible oil like Jatropha could be a good substitute to diesel fuel in diesel engine in the near future as far as decentralized energy production is concerned. In view of comparable engine performance and reduction in most of the engine emissions, it can be concluded and biodiesel derived from Jatropha and its blends could be used in a conventional diesel engine without any modification.     

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.