Biodiesel fuel in diesel micro-turbine engines: Modelling and experimental evaluation

Many performance and emission tests have been carried out in reciprocating diesel engines that use biodiesel fuel over the past years and very few in gas turbine engines. This work aims at assessing the thermal performance and emissions at full and partial loads of a 30 kW diesel micro-turbine engine fed with diesel, biodiesel and their blends as fuel. A cycle simulation was performed using the Gate Cycle GE Enter software to evaluate the thermal performance of the 30 kW micro-turbine engine. Performance and emission tests were carried out on a 30 kW diesel micro-turbine engine installed in the NEST laboratories of the Federal University of Itajubá, and the performance results were compared with those of the simulation. There was a good agreement between the simulations and the experimental results from the full load down to about 50% of the load for diesel, biodiesel and their blends. The biodiesel and its blends used as fuel in micro-turbines led to no significant changes in the engine performance and behaviour compared to diesel fuel. The exhaust emissions were evaluated for pure biodiesel and its blends and conventional diesel. The results revealed that the use of biodiesel resulted in a slightly higher CO, lower NO_x and no SO₂ emissions.     

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.     

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.     

Review of NOx reduction technologies in CI engines fuelled with oxygenated biomass fuels

Oxygenated fuels like biodiesel and alcohols have the potential to provide a reliable and a cost effective alternative to India's increasing future energy demands. They have a prospective future since they are renewable and can be produced easily in India's rural areas. Due to rapid industrialization and the increased number of vehicles on the road, the energy needs of the country are increasing rapidly. Oxygenated fuels can substantially replace the large demand for diesel to generate power for the industries and to fuel diesel engines of the vehicles. In spite of the many advantages of using them, most of the researchers have reported higher NO_x emissions, which is a deterrent to the market expansion of these fuels. The present program aims to review the NO_x emissions from the CI engines fuelled with oxygenated fuels. To meet the stringent emission norms, the various NO_x reduction technologies like use of additives, retarded fuel injection timing, biodiesel emulsion with water, and exhaust gas recirculation are reviewed. The results of the most effective and low cost technique of EGR in DI diesel engine fuelled with biodiesel–diesel blends and tri-compound oxygenated diesel fuel blends (ethanol–biodiesel–diesel fuel blends and methanol–biodiesel–diesel fuel blends) are presented.     

Hydrogen addition to tea seed oil biodiesel: Performance and emission characteristics

Compression ignition engines are the dominant tools of the modern human life especially in the field of transportation. But, the increasing problematic issues such as decreasing reserves and environmental effects of diesel fuels which is the energy source of compression ignition engines forcing researchers to investigate alternative fuels for substitution or decreasing the dependency on fossil fuels. The mostly known alternative fuel is biodiesel fuel and many researchers are investigating the possible raw materials for biodiesel production. Also, hydrogen fuel is an alternative fuel which can be used in compression ignition engines for decreasing fuel consumption and hazardous exhaust emissions by enriching the fuel. In this study, influences of hydrogen enrichment to diesel and diesel tea seed oil biodiesel blends (B10 and B20) were investigated on an unmodified compression ignition engine experimentally. In consequence of the experiments, lower torque and higher brake specific fuel consumption data were measured when the engine was fuelled diesel biodiesel blends (B10 and B20) instead of diesel fuel. Also, diesel biodiesel blends increased CO₂ and NO_x emissions while decreasing the CO emissions. Hydrogen enrichment (5 l/m and 10 l/m) was improved the both torque and brake specific fuel consumption for all test fuels. Furthermore, hydrogen enrichment reduced CO and CO₂ emissions due to absence of carbon atoms in the chemical structure for all test fuels. Increasing flow rate of hydrogen fuel from 5 l/m to 10 l/m further improved performance measures and emitted harmful gases except NO_x. The most significant drawback of the hydrogen enrichment was the increased NO_x emissions.     

Emission analysis of Azolla methyl ester with BaO nano additives for IC engine

The aim of this work is to decrease emissions in diesel engines fueled with diesel and algae biodiesel blends and also addition of BiO nanoparticles. Azolla algae can be used to produce biodiesel, because of high oil content. The biodiesel was prepared by using Azolla algae non-edible oil through transesterification process. In the present study, the BaO nano additives into the algae oil-based methyl ester blend and its diesel blends are analyzed the emission characteristic at different load. Addition of BaO nanoparticle was a strategy to reduce emission (CO, HC, and O₂) of the biodiesel.     

Study of antioxidant effect on oxidation stability and emissions in a methyl ester of neem oil fuelled DI diesel engine

Biodiesel as an alternative diesel fuel prepared from vegetable oils or animal fats has attracted more and more attention because of its renewable and environmental-friendly nature. But biodiesel undergoes oxidation and degenerate more quickly than mineral diesel. Further several studies report NO_x emissions increases for biodiesel fuel compared with conventional diesel fuel. In this paper, the experimental investigation of the effect of antioxidant additive (Butylated hydroxytoluene) on oxidation stability and NO_x emissions in a methyl ester of neem oil fuelled direct injection diesel engine has been reported. The antioxidant additive is mixed in various proportions (100–400 ppm) with methyl ester of neem oil. The oxidation stability was tested in Rancimat apparatus and emissions, performance in a computerized 4-stroke water-cooled single cylinder diesel engine of 3.5 kW rated power. Results show that the antioxidant additive is effective in increasing the oxidation stability and in controlling the NO_x emissions of methyl ester of neem oil fuelled diesel engines.     

Comparative study of biodiesel from Jatropha and orange peel oils as pilot fuels in a dual-fuel engine

The diesel-like properties of biodiesel make it a good alternative for CI engines. In the present work, the scope of biodiesel as a pilot fuel has been studied and compared with diesel. The results show that the use of Jatropha oil methyl ester (JOME) and orange peel oil methyl ester (OPOME) as pilot fuel improves BTE and BSFC of dual-fuel engines compared to diesel as a pilot fuel. The use of JOME and OPOME as a pilot fuel for CNG also decreases the emissions like unburnt hydrocarbons, CO, and smoke. However, NO_X emissions increase at higher load. In contrast, use of biodiesel as pilot fuel improves the performance and emissions characteristics of dual-fuel engines.     

Experimental investigation of control of NOx emissions in biodiesel-fueled compression ignition engine

Biodiesel is an alternative fuel consisting of the alkyl esters of fatty acids from vegetable oils or animal fats. Vegetable oils are produced from numerous oil seed crops (edible and non-edible), e.g., rapeseed oil, linseed oil, rice bran oil, soybean oil, etc. Research has shown that biodiesel-fueled engines produce less carbon monoxide (CO), unburned hydrocarbon (HC), and particulate emissions compared to mineral diesel fuel but higher NO_x emissions. Exhaust gas recirculation (EGR) is effective to reduce NO_x from diesel engines because it lowers the flame temperature and the oxygen concentration in the combustion chamber. However, EGR results in higher particulate matter (PM) emissions. Thus, the drawback of higher NO_x emissions while using biodiesel may be overcome by employing EGR. The objective of current research work is to investigate the usage of biodiesel and EGR simultaneously in order to reduce the emissions of all regulated pollutants from diesel engines. A two-cylinder, air-cooled, constant speed direct injection diesel engine was used for experiments. HCs, NO_x, CO, and opacity of the exhaust gas were measured to estimate the emissions. Various engine performance parameters such as thermal efficiency, brake specific fuel consumption (BSFC), and brake specific energy consumption (BSEC), etc. were calculated from the acquired data. Application of EGR with biodiesel blends resulted in reductions in NO_x emissions without any significant penalty in PM emissions or BSEC.     

Emission analysis on compression ignition engine fueled with lower concentrations of Pithecellobium dulce biodiesel‐diesel blends

The present study investigates the effect of Pithecellobium dulce biodiesel (PDBD) blends with diesel fuel on compression ignition (CI) engine emissions. Initially, PDBD was prepared by using a base transesteri?cation process. The GC‐MS, ¹H NMR, and Fourier transform infrared characterization of PDBD was carried out, and fuel properties were determined. The experiments were conducted on a single cylinder, CI engine using three blended fuels: PDBD5 (5% biodiesel and 95% diesel), PDBD10 (10% biodiesel and 90% diesel), and PDBD20 (20% biodiesel and 80% diesel). The experimental outcomes revealed that 20% of PDBD reduces 19.64% carbon monoxide, 17.64% hydrocarbon, and 6.73% oxides of nitrogen emissions. Furthermore, from this study, it was inferred that the PDBD20 blend could be used as an alternative fuel for CI engines with no modi?cations in engine design.     

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.     

Improving the low temperature properties of biodiesel fuel

The use of biodiesel as a diesel fuel extender and lubricity improver is rapidly increasing. While most of the properties of biodiesel are comparable to petroleum based diesel fuel, improvement of its low temperature flow characteristic still remains one of the major challenges when using biodiesel as an alternative fuel for diesel engines. The biodiesel fuels derived from fats or oils with significant amounts of saturated fatty compounds will display higher cloud points and pour points. This paper is aimed to investigate the cold flow properties of 100% biodiesel fuel obtained from Madhuca indica, one of the important species in the Indian context. In this paper, the cold flow properties of biodiesel were evaluated with and without pour point depressants towards the objectives of identifying the pumping and injecting of these biodiesel in CI engines under cold climates. Effect of ethanol, kerosene and commercial additive on cold flow behavior of this biodiesel was studied. A considerable reduction in pour point has been noticed by using these cold flow improvers. The performance and emission with ethanol blended Mahua biodiesel fuel and ethanol–diesel blended Mahua biodiesel fuel have also been studied. A considerable reduction in emission was obtained. Ethanol blended biodiesel is totally a renewable, viable alternative fuel for improved cold flow behavior and better emission characteristics without affecting the engine performance.     

NOX emissions of compression ignition engines fueled with various biodiesel blends: A review

There are some challenges about NO_X emissions exhausted from diesel engines fueled with biodiesel. Due to increasingly stringent emission regulations, the different methods such as varying the engine operating parameters, treatment with antioxidant additive and blending fuels have been adapted to reduce emissions of biodiesel combustion. One of the effective methods is the combustion of dual or blending fuels. Various fuels such as gasoline, hydrogen, natural gas, biogas, different types of alcohols and also fuel additives have been used to reduce biodiesel disadvantages. This study reviews the potential of the different fuels as an additive in biodiesel fuel in correspond to reduce NO_X emissions. The general reduction of NO_X has been observed with the presence of gasoline, biogas and alcohols in biodiesel blends. The reduction of NO_X in biodiesel-hydrogen, biodiesel-diesel or biodiesel–CNG combustion has not been observed through all engine conditions. Moreover the retarding injection timing, the lower injection pressure, EGR higher than 30% can result in the reduced NO_X emissions. However it seems the decrease in NO_X emissions can be achieved by the use of most fuels in blending with biodiesel under all engine operating conditions, if only the proper injection parameters and blending proportions of fuels are set.     

Determination of ecological efficiency in internal combustion engines: The use of biodiesel

This paper evaluates and quantifies the environmental impact from the use of some renewable fuels and fossils fuels in internal combustion engines. The following fuels are evaluated: gasoline blended with anhydrous ethyl alcohol (anhydrous ethanol), conventional diesel fuel, biodiesel in pure form and blended with diesel fuel, and natural gas. For the case of biodiesel, its complete life cycle and the closed carbon cycle (photosynthesis) were considered. The ecological efficiency concept depends on the environmental impact caused by CO₂, SO₂, NO_x and particulate material (PM) emissions. The exhaust gases from internal combustion engines, in the case of the gasoline (blended with alcohol), biodiesel and biodiesel blended with conventional diesel, are the less polluting; on the other hand, the most polluting are those related to conventional diesel. They can cause serious problems to the environment because of their dangerous components for the human, animal and vegetable life. The resultant pollution of each one of the mentioned fuels are analyzed, considering separately CO₂, SO₂, NO_x and particulate material (PM) emissions. As conclusion, it is possible to calculate an environmental factor that represents, qualitatively and quantitative, the emissions in internal combustion engines that are mostly used in urban transport. Biodiesel in pure form (B100) and blended with conventional diesel as fuel for engines pollute less than conventional diesel fuel. The ecological efficiency for pure biodiesel (B100) is 86.75%; for biodiesel blended with conventional diesel fuel (B20, 20% biodiesel and 80% diesel), it is 78.79%. Finally, the ecological efficiency for conventional diesel, when used in engines, is 77.34%; for gasoline, it is 82.52%, and for natural gas, it is 91.95%. All these figures considered a thermal efficiency of 30% for the internal combustion engine.     

Biodiesel as alternative fuel: Experimental analysis and energetic evaluations

This paper presents the first results of an investigation carried out by the authors on the potentialities of biodiesel as an alternative fuel based on strategic considerations and field experiences in boilers and diesel engines.The operation of a biodiesel fuelled boiler has been checked for some months. The engines have been bench-tested and then installed on urban buses for normal operation. Distances, fuel consumption and emissions (CO₂, CO, HC and NO_X) have been monitored; in addition devices wear and tear, oil and air filters dirtiness and lubricant degradation have been checked.Further investigations have also been devoted to assess some environmental aspects of bio-diesel. In particular the benefit of biodiesel to the total net emission of CO₂ during the whole life cycle has been studied and the net energy requirement has been evaluated.Finally, the global environmental support to the production of biodiesel has been studied according to the emergy analysis.     

Investigation on combustion and emission characteristics of hydrogen-enriched dual-fuel engine operated under waste frying oil biodiesel

Using nonedible waste frying oil (WFO) as biodiesel and hydrogen in the mix composition may partly replace significant quantities of diesel fuel and help reduce fossil fuel reliance. The combination of diesel fuel, waste-fired biodiesel, and hydrogen gas can improve the performance, combustion, and emissions of single-fuel and dual-fuel diesel engines. This may lead to a novel alternative fuel mix pattern and modification for diesel engines, which is the research gap. Although there has been some research on waste-fired biodiesel and hydrogen gas-powered dual-fuel engines with the goal of partly replacing fossil fuels to a larger degree, there has been very little progress in this area. As a result, the current research effort focuses on using diesel fuel (100%, 30%, and 60%), waste-fired biodiesel (at 100%, 70%, and 40%), and hydrogen gas as fuel sources (5 and 10 liters per minute [LPM]). According to the current experiment, it was perceived in both dual-fuel and single-fuel modes. Under duel-fuel mode, the engine results for WFOB70D30 + H10 fuel blend had higher 4.2% (brake thermal efficiency [BTE]), 19.72% (oxides of nitrogen [NO_x]), and 9.09% (ignition delay [ID]) with a minimal range of (in-cylinder pressure, MFB, volumetric efficiency and heat release rate [HRR]) and a dropped rate of 4.34% (brake-specific energy consumption [BSEC]), 33.33% (carbon monoxide [CO]), 39.28% (hydrocarbons [HC]), 9.43% (smoke), and 6.97% (combustion duration [CD]) related to diesel fuel at peak load. However, single-fuel powered diesel engines provide minimal performance for the WFOB40D60 fuel blend with (11.32% lower BTE and 2.04% higher BSEC) and minimal rate of combustion (lower cylinder pressure, 2.12% minimal CD, 14.72% higher ID, minimal HRR combustion, volumetric efficiency, and MFB). Emitted fewer emissions (9.09% less CO, 4.87% less HC, 0.92% higher NO_x, and 1.69% more smoke) than diesel fuel at peak load. Therefore, it was concluded that adding 10 LPM of hydrogen gas to the biodiesel under a dual-fuel condition leads to better combustion, better performance, and less pollution than the single-fuel mode of operation.     

Saving energy and reducing pollution by use of emulsified palm-biodiesel blends with bio-solution additive

Advances in biodiesel, emulsified diesel and artificial chemical additives are driven by consumer demand to save energy and reduce emissions from diesel engines. However, the effect of emulsified bio-solution/palm-biodiesel/diesel blends in diesel engines has not been assessed. Experimental results in this work demonstrate that the emulsified bio-solution/palm-biodiesel/diesel blends have the advantage in saving energy and reducing emissions of both polycyclic aromatic hydrocarbons (PAHs) and particulate matter (PM) from diesel engines. When comparing with P0 (premium diesel fuel as base fuel), E16P20 fuel (16 vol% bio-solution + 20 vol% palm-biodiesel + 64 vol% P0, an additional 1 vol% surfactant) saved 12.4% fuel consumption and reduced emissions of PM by 90.1%, total PAHs by 69.3%, and total BaP_eq (benzo[a]pyrene equivalent concentration) by 69.6%. Emulsified palm-biodiesel with bio-solution can be considered as a clean and alternative fuel.     

Environment effect of La2O3 nano-additives on microalgae-biodiesel fueled CRDI engine with conventional diesel

In this present work, corn oil biodiesel with La₂O₃ was used as an additive with neat diesel fuel and blends were prepared. La₂O₃ nanoparticles are dispersed in the emulsions with different dosage levels of 50, 75, and 100 ppm. A single-cylinder, four-stroke CRDI diesel engine is made to run on different fuel concentrations to study the effect of emission characteristics of the fuel. The test engine was operated under constant engine speed (1500 rpm) and different engine load test conditions. According to the experimental results, fuel blends with biodiesel fuel emission increases CO₂ and NOx and reduces the CO, HC, and smoke emissions compared with the B20 fuel.     

Effect of ethanol blending with biodiesel on engine performance and exhaust emissions in a CI engine

The use of biodiesel as an alternative diesel engine fuel is increasing rapidly. However, due to technical deficiencies, they are rarely used purely or with high percentages in unmodified diesel engines. Therefore, in this study, we used ethanol as an additive to research the possible use of higher percentages of biodiesel in an unmodified diesel engine. Commercial diesel fuel, 20% biodiesel and 80% diesel fuel, called here as B20, and 80% biodiesel and 20% ethanol, called here as BE20, were used in a single cylinder, four strokes direct injection diesel engine. The effect of test fuels on engine torque, power, brake specific fuel consumption, brake thermal efficiency, exhaust gas temperature, and CO, CO₂, NO_x and SO₂ emissions was investigated. The experimental results showed that the performance of CI engine was improved with the use of the BE20 especially in comparison to B20. Besides, the exhaust emissions for BE20 were fairly reduced.     

An outcome of quaternary fuel blended Fe3O4-doped reduced graphene oxide nanocomposite on the diesel engine

The study includes the use of alcohols in conjunction with diesel as a binary fuel and biodiesel. In addition, this study was conducted on quaternary fuels (premium diesel, waste cooking biodiesel, n-butanol, and bioethanol), including Fe₃O₄ (iron(III) oxide)-doped reduced graphene oxide (rGO) nanocomposite to reduce the use of fossil fuels, their cost, and energy demand. It includes 10% bioethanol, 5%–20% n-butanol, 25 ppm Fe₃O₄-doped rGO nanocomposite, and 20% and 100% waste cooking biodiesel, all of which have been tested in a diesel engine to ensure that they are suitable for use. The findings were compared to those obtained with premium diesel, ranging from 50% to 100% at full engine load conditions. In comparison to 100% premium diesel fuel, the fuel blend (Blend G) had 37.50% brake thermal efficiency and 0.46% (brake-specific energy consumption), as well as lower rates of 316.2% carbon monoxide, 198.80% hydrocarbon, and 80.01% smoke with 28.10% higher oxides of nitrogen (NOx). Adding 20% n-butanol to premium diesel, as well as waste cooking biodiesel, bioethanol, and Fe₃O₄-doped rGO nanocomposite fuel blends, was used in this study to improve the performance of the diesel engine and reduce some of the NOx emissions. In the near future, these fuel blends may be a viable alternative combination for the diesel engine.