Density Of Biodiesel Research Articles

Multi‐aspect assessment and multi‐objective optimization of preheated tallow biodiesel‐diesel blend as alternate fuel in CI engine

AbstractThis study meticulously examined the impact of preheated tallow biodiesel on the performance and emission characteristics of a diesel engine. Employing a single‐cylinder, water‐cooled diesel engine configured with exhaust gas recirculation in this investigation, exhaust gas temperature (EGT) could be used to preheat the biodiesel, reducing its viscosity and density. This improvement in viscosity and density could enhance the injection process, which is often hindered by the higher density and viscosity of biodiesel compared with diesel fuel. The investigation achieved a peak preheat temperature of 70°C for the biodiesel, leading to notable improvements in brake thermal efficiency and brake power, particularly under high‐load conditions. A significant reduction in emissions was observed, with hydrocarbon and carbon monoxide levels decreasing by 46.87% and 50%, respectively, when using preheated biodiesel. To refine the engine's performance further, this study utilized response surface methodology (RSM) for the optimization of operational parameters, including injection timing, engine load, and biodiesel preheat temperatures. Optimal conditions were identified at an injection timing of 21° before top dead centre, a preheat temperature of 64°C, and an engine load of 45.45% for which output response was 18.68% brake thermal efficiency, 307°C EGT, 0.0247% vol. CO, 15.32 ppm hydrocarbons, and 131.37 ppm nitrogen oxides (NOx). The successful implementation of preheated tallow biodiesel signifies a crucial step forward in the pursuit of a more sustainable and efficient transportation industry. This advancement holds the promise of reducing reliance on traditional fossil fuels, thereby contributing to the global efforts towards achieving a more environmentally friendly energy landscape.

Optimization of the full-load combustion schemes of n-butanol/biodiesel reactivity-controlled compression ignition (RCCI) toward high-efficiency and low-emission engines

Biodiesel and n-butanol, as popular alternative fuels, can be used in advanced reactivity-controlled compression ignition (RCCI) engines for efficient and clean combustion. However, the complex interactions between n-butanol and biodiesel, as well as the best combustion schemes at different loads, remain poorly understood. Given this, the objective of this paper is to identify optimal fuel organizations for n-butanol/biodiesel RCCI engines across different load scenarios by combining engine simulation with a global optimization algorithm, explore the potential synergies of control parameters, and analyze microscopic dual-fuel interactions based on the integrated average reaction path analysis. Results show that the optimal scheme at low load employs almost homogeneous fuel-air mixtures at elevated temperature atmosphere above 390 K, with n-butanol energy share exceeding 96% and optimal biodiesel injection timing between −70 and −50 °CA. Higher n-butanol ratio coupled with increased intake temperature improves engine performance. For mid load, biodiesel injection timing is retarded to −55 to −30 °CA, and biodiesel proportion is increased to introduce reactivity stratification, while maintaining its energy share below 20% to mitigate NOx emissions. Notably, biodiesel density is identified as the primary physical property influencing NOx formation. At high load, a split combustion scheme involving premixing and subsequent diffusion combustion is optimal. The physical effects of n-butanol addition minimally impact the low-temperature ignition of biodiesel, while its chemical effects significantly defer the low-temperature reactivity. The reaction path analysis reveals that n-butanol competes with biodiesel for OH radical consumption, with a large proportion of OH and HO2 consumed in the cyclic reactions of nC4H9OH and nC4H8OH. Adjusting the reactivity stratification affects the reaction state of n-butanol entrained by the biodiesel jets. Higher reactivity gradient intensifies biodiesel reactions to induce the pyrolysis of the involved n-butanol through nC4H8OH => 2C2H4 + OH, therefore resulting in more staged heat release.

Determination of the effect of low concentration titanium dioxide nano fuel additive in biodiesel on performance and emissions

In this study, the effect of nanoparticle addition into rapeseed methyl ester (R0) produced by the transesterification method on engine performance and emissions was experimentally investigated. Titanium dioxide was used as a nano fuel additive and was added to the test fuels at rates of 50 ppm (RTi50) and 75 ppm (RTi75) using an ultrasonic mixer. The effect of titanium dioxide on engine performance and exhaust emissions was experimentally determined by taking advantage of its photocatalysis effect and chemical reaction accelerator properties. Additionally, titanium dioxide additive reduced the viscosity and density of biodiesel fuel, resulting in higher micro explosion. According to the test results carried out at 4 different engine loads, brake specific fuel consumption decreased by 7.51% and 8.62% in RTi50 and RTi75 fuels compared to R0 fuel. Brake thermal efficiency increased by 2.47% and 6.21%, respectively. The improvement in combustion achieved by the nano additive increased the conversion of CO emissions into CO2, increased NOX emissions, reduced smoke emissions and caused more complete combustion products to come out of the exhaust.

Blending biomass-based liquid biofuels for a circular economy: Measuring and predicting density for biodiesel and hydrocarbon mixtures at high pressures and temperatures by machine learning approach

Circular economy is an efficient approach to deal with the rapidly increasing demand for energy and its environmental impact. It involves switching to renewable and sustainable energy sources. By providing an alternative to traditional energy resources, biodiesel promotes a circular economy paradigm that embraces renewable energies rather than fossil fuels. As an alternative to fossil fuels, liquid biodiesel helps to improve energy efficiency and reduce pollution. Furthermore, blending biodiesel has proven to be economically and environmentally viable. Knowledge of the thermodynamic properties of biodiesel, such as densities and coefficients of expansivity and compressibility, plays an important role in understanding and determining the behavior of the fuel under different operating conditions. The blend densities of Soybean Oil Biodiesel (SOB) with hexane and Waste Cooking Oil Biodiesel (WCOB) with heptane in four volume ratios were experimentally studied. An Anton Paar vibrating tube densimeter HPM DMA has been used for accurate measurements of densities of the biofuels and their blends. Density measurements were performed at temperatures ranging from 298.15 K to 393.15 K, and pressures between 0.1 MPa and 140 MPa. This work also aims to develop accurate prediction models of the properties of biodiesel blends under various conditions, such as changes in temperature and pressure, which are essential for optimizing energy production processes and engine performance. In this context, the dataset was first investigated with Tait Equation of State (Eos) to determine thermodynamic parameters which including isothermal compressibility and isobaric expansivity. It showed generally low standard deviations. Furthermore, these new experimental densities were also modeled with Artificial Neural Network (ANN) as a machine learning method. This paper models proved that the machine learning method is a suitable tool to model the thermo-physical characteristics of liquid fuels. The findings of this study have the potential to provide valuable guidance to engine engineering applications developers regarding operating conditions and the selection of suitable biodiesel for their system.

Comparison of the physicochemical properties of microalgae biodiesel with other oilseed feedstocks for sustainable energy production: A meta-analysis

Biodiesel has emerged as an alternative diesel fuel, offering environmental advantages such as biodegradability, non-toxicity, and low emissions. This study conducted a meta-analysis to compare microalgae biodiesel with other oilseed feedstocks for sustainable energy production. The analysis involved compiling a database of published articles on biodiesel derived from microalgae and plant seeds. The results demonstrated that microalgae are one of the most promising feedstocks among various oilseeds. The cetane number and fuel density of biodiesel from microalgae were significantly higher than those from plant seeds (p<0.05). In conclusion, microalgae are a suitable feedstock for biodiesel production, surpassing traditional oil and crop sources, and can potentially mitigate the expansion of conventional agricultural practices. Moreover, microalgae can be cultivated year-round and in various climates, allowing for extended production seasons and site flexibility. Additionally, their utilization of waste streams as nutrient sources and non-requirement of arable land can contribute to reducing the environmental impact on other industries.

Hybrid CaO/ZnFe2O4 Modified with Al2O3 as a Green Catalyst for Biodiesel Production from Waste Cooking Oil

In this work, biodiesel was produced from waste cooking oil (WCO) via a green catalyst of CaO-ZnFe2O4 modified Al2O3. The catalyst was characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray (EDX), SEM-mapping, Brunauer-Emmett-Teller (BET), transmission electron microscopy (TEM) analyses. The catalyst performance was studied in the transesterification reaction of WCO conversion to biodiesel. The catalytic activity increased with the combination of nanoparticles effect and support catalysts obtained biodiesel yield of nano-Al2O3, nano-CaO, ZnFe2O4, CaO-ZnFe2O4, and CaO-ZnFe2O4/Al2O3 is 36.86%, 67.16%, 74.83%, 86.54%, and 93.41%, respectively. The best biodiesel yield was 93.41% with a mass ratio of Al2O3 to CaO-ZnFe2O4 (2:1). The physicochemical properties (acid number, density, kinematic viscosity, flash point, and cetane number) of biodiesel under the optimal conditions agreed with the ASTM standard. These results show that the developed nanocomposite has great potential to reduce biodiesel production costs because derived from WCO. In conclusion, CaO-ZnFe2O4 modified Al2O3 as a catalyst has a high potential for biodiesel production on a large scale.

Physicochemical Characterization and Butanol Impact on Canola and Waste Cooking Oil Biodiesels: A Comparative Analysis with Binary Biodiesel Blends

In this study, the physicochemical properties of canola and waste cooking oil biodiesels, as well as various binary biodiesel blends, were investigated according to TS EN 14214 and ASTM D 6751 standards. Critical parameters such as density, kinematic viscosity, cold filter plugging point (CFPP), calorific value, flash point, copper strip corrosion, water content, and ester yield were evaluated. The findings highlighted the notable density of C100 and W100 biodiesels, with the addition of butanol reducing density. While viscosity values adhered to standards, the addition of butanol was observed to decrease viscosity. CFPP values indicated compliance with standards only for C100 and C75W25. Flash points of C100 and W100 biodiesels met standards, but the addition of butanol to binary biodiesel blends lowered flash points. Copper strip corrosion values were determined to comply with standards for all fuels. Calorific values demonstrated the prominence of C100 and W100 biodiesels, with the addition of butanol observed to decrease calorific values in binary biodiesels. While water content favored canola biodiesel over waste cooking oil biodiesel, the addition of butanol to binary biodiesels increased water content. Regarding ester yield, C100 biodiesel exhibited the highest yield, and the addition of butanol to binary biodiesels increased ester yield. In conclusion, this study thoroughly analyzed the physicochemical properties of biodiesel and blend fuels, revealing the impact of butanol addition on these properties.

Experimental Investigation of Cottonseed Biodiesel and Biodiesel Blends in a 14 kW Diesel Generator: Effects on Performance, Emissions, and Engine Parameters

This investigation presents an experimental study on the performance, specific fuel consumption, and exhaust emissions of a 14-kW diesel engine generator fueled with neat cottonseed biodiesel and biodiesel/diesel blends. Cotton biodiesel was chosen due to its importance as an agricultural crop and potential as a biodiesel feedstock. The fuels tested were (B100 - pure cotton biodiesel), (B7 - 7% biodiesel, 93% Petro diesel), (B20 - 20% biodiesel), (B30 -30% biodiesel), (B50 - 50% biodiesel), and (B70 - 70% biodiesel). The generator was tested at various loads from 0-14 kW. Properties like viscosity, density, and calorific value were measured for each fuel. The results showed that brake thermal efficiency increased with load for all fuels but was lower for higher biodiesel blends. Exhaust gas temperature followed a similar trend. Specific fuel consumption increased with biodiesel content, attributed to the lower energy density of Biodiesel. B100 had the highest NOx emissions but the lowest carbon monoxide and smoke emissions. The study concludes that cottonseed biodiesel and blends can replace Petro diesel in diesel generators. Increasing biodiesel content causes slight reductions in performance but improvements in emissions. The results provide insights into using cotton biodiesel in engines and generators.

Evaluation of Performance of a CI Engine Fueled With Biodiesel Produced from Unused Algae

Abundant availability and easy culture process of algae make it a better resource than other vegetable crops for biodiesel production. The oil (with 21% FFA content) extracted from the unused, mixed culture of algae in this experiment was used to produce biodiesel by an' acid esterification followed by alkaline esterification' procedure. After confirming the properties of the biodiesel to be within the limit of ASTM standard, three biodiesel blends (B10, B20 and B30) were used in an internal combustion engine (Four stroke single cylinder VCR engine) and the performance of the engine was observed at different engine loads (0%, 20%, 40%, 80%, 100%, 120%). The little higher brake specific fuel consumption (0.22kg/KWh, 0.25 kg/KWh, 0.26kg/KWh and 0.21kg/KWh respectively for B10, B20, B30 and petro-diesel at overload condition), lower brake power (3.41 kW, 3.37 kW, 3.25 kW, 3.39 kW for diesel, B10, B20 and B30 respectively for B10, B20, B30 and petro-diesel) and mechanical efficiency (63.34, 51.43%, 52.06% and 51.43% for petro-diesel, B10, B20 and B30 respectively) for biodiesel blends took place which might be the results of lower calorific value (40800 kJ/kg), higher density (875.27kg/m3) and viscosity (3.14 mm2/s) of the algal biodiesel than diesel.

Effects of Diacetinmonoglycerides and Triacetin on Biodiesel Quality

Triacetin offers a higher added value compared to glycerol and can be obtained during the interesterification reaction between methyl acetate and triglycerides. In the same reaction, diacetinmonoglyceride is produced as an intermediate compound. The objective of this study was to assess whether the biodiesel produced, with varying concentrations of these compounds, meets the requirements established by the EN 14214 and ASTM D6751 standards. To achieve this, several properties were measured, including density, kinematic viscosity, cloud point, pour point, cold filter plugging point, methyl ester content, mono-, di-, triglyceride and total glycerol content, as well as the vacuum distillation curve. These measurements were conducted on mixtures of triacetin, diacetinmonoglyceride, and biodiesel, using different types of biodiesel such as palm, soybean, sunflower and rapeseed. Additionally, the solubility of these ternary mixtures in conventional diesel was evaluated. The results indicated that the EN 14214 standard imposes limits on the density and viscosity of biodiesel, restricting the content of triacetin (up to 5–10% by weight) and diacetinmonoglyceride (up to 3–4% by weight). However, the content of monoglycerides presents the most restrictive condition, as the chromatographic technique used cannot differentiate between monoglycerides and diacetinmonoglycerides. Consequently, their content is limited to a range of 0.15% to 0.70% by weight, depending on the prevailing climate conditions. Similarly, the ASTM D6751 standard sets a limitation of 0.40% by weight for monoglycerides to three out of six grades of biodiesel. Based on the findings of this study, which demonstrate that diacetinmonoglycerides do not have adverse effects on the cold performance of biodiesel, the inclusion of diacetinmonoglycerides in biodiesel production would still necessitate the development of standard test methods capable of differentiating between monoglycerides and diacetinmonoglycerides.

Performance Evaluation of a CI Engine Using Binary, Ternary, and Quaternary Bio-Diesel Fuel Blends

The present study utilizes dual biodiesel-alcohol blends to evaluate the engine performance. Five test fuels were prepared on a volume basis with different constituting percentages, each consisting of 70 % pure diesel (D70), a binary blend of biodiesel: B1 (WCO30), a ternary blend of biodiesel: B2 (WCO15 and WCCO15) and three quaternary blends: B3 (WCO10, WCCO15, Bu5), B4 (WCO15, WCCO10, Bu5) and B5 (WCO10, WCCO10, Bu10). The biodiesel is made from used cooking oil. The effects of each blend on engine performance were examined by performing the engine test on a single-cylinder, four-stroke, water-cooled Kirloskar compression ignition (CI) engine at various engine speeds and loads. The indicated power (IP), brake power (BP), friction power (FP), fuel consumption (FC), and mechanical efficiency (%) were evaluated, and the experimental results show that the performance is best for B3 when run with 75 % of the maximum load capacity of the engine. The study thus justifies that to lower the density and viscosity of biodiesel fuel, adding alcohol can be acknowledged as a valuable application to boost the engine's brake thermal efficiency (BTE). This also lowers the emissions of oxides of nitrogen (NOx), carbon monoxide (CO), and hydrocarbons (HC).

The influence of catalyst on the characteristics of biodiesel from waste cooking oil

The aim of this research was to investigate the influence of catalyst on the flash point, viscosity, density, and iodine value of biodiesel. The raw material used in biodiesel production was waste cooking oil. The transesterification process was employed by reacting the catalyst and methanol, followed by mixing them with the waste cooking oil simultaneously. The catalyst concentration variations used in this study were 0.25% and 0.5%. The resulting transesterification mixture was left to settle for approximately 10 minutes. The biodiesel and glycerol were separated after settling, and the biodiesel was washed with distilled water at a temperature of 50°C and then evaporated at 100°C. The flash point test results for catalyst concentrations of 0.25% and 0.5% were 58°C and 48.5°C, respectively. The viscosity test results for catalyst concentrations of 0.25% and 0.5% were 4.567 x 10-6 m2/s and 4.625 x 10-6 m2/s, respectively. The density test results for catalyst concentrations of 0.25% and 0.5% were 889 kg/m3 and 888.3 kg/m3, respectively. The iodine value test results for catalyst concentrations of 0.25% and 0.5% were 112.2 g I2/100g and 114 g I2/100g, respectively. Based on the test data, the flash point, viscosity, density, and iodine value were obtained. The test results indicated that the flash point values from both experiments did not meet the biodiesel quality standards. However, the viscosity and density test results from both experiments met the biodiesel quality standards and were suitable for use. Regarding the iodine value test, the characteristics of the biodiesel from both experiments did not fully meet the biodiesel standard, although the results obtained were not significantly different from the quality standards set by the Ministry of Energy and Mineral Resources

Effect of Density and Viscosity on Injection Characteristic of Jatropha - waste Cooking Oil Biodiesel Mixture.

Biodiesel has an important role in the world of transportation and its existence is taken into account. So the availability of biodiesel fuel in the future will be difficult to eliminate and must continue to be fulfilled. Therefore, it is necessary to innovate to increase the availability of biodiesel fuel. Biodiesel can be made from biological materials and includes renewable energy as a substitute for diesel oil. The production of biodiesel in this study jatropha and waste cooking oil as raw materials. This study aims to determine the effect of density and viscosity on the injection characteristics of jatropha-waste cooking oil biodiesel mixtures (1:4 and 4:1) on various B5-B40 fuels. Production of biodiesel from jatropha and waste cooking oil through degumming, esterification and transesterification processes. The results showed that the jatropha-waste cooking oil biodiesel mixed with 1:4 level B15 and 4:1 mixed with B10 level complied with SNI 7182-2015 biodiesel standards. The higher the density and viscosity values of jatropha-waste cooking oil biodiesel, the narrower the spray angle and the longer the spray penetration

Measurement and prediction of the volumetric and acoustic properties of two biodiesel fuels up to 200 MPa

This work presents experimental data on sound velocities and densities for two biodiesel fuels, namely sunflower methyl ester and a blend of Palm, Rapeseed, and Soybean methyl esters at pressures ranging from atmospheric to 200 MPa and temperatures from 293.15 to 393.15 K. Speed of sound data were obtained up to 200 MPa using a pulsed echo method. Density was determined by measuring the period of a vibrating tube up to 100 MPa and by integrating the sound velocity between 100 and 200 MPa. These measurements were coupled to determine other properties, such as isothermal compressibility, isentropic compressibility, and acoustic impedance, which strongly influence the injection process in diesel engines. The experimental data were compared with a set of models previously developed to predict the density and sound velocity of biodiesels under high pressure based on their fatty acid ester composition.

A comparative study of the effect of field practices on the fuel properties of groundnut kernels biodiesel

The impact of pre-harvest treatments (field practices) on the fuel (biodiesel) properties produced from groundnut kernels was evaluated in this work. Ahigh-quality oil-yielding groundnut hybrid (SAMNUT 11) was grown under five different soil treatment regimes. The regimes were organic and conventional, though the treatment concentrations were systematically varied. Biodiesels produced from matured kernels (for the different treatment plans) were tested following the American Society for Testing Materials (ASTM) International and European Biodiesel (EN) procedures. Results obtained revealed that the biodiesel density ranged between 856 kg/m3 and 869 kg/m3, the acid value ranged between 0.695% and 1.118%, the iodine value ranged from 27.54 mg/L to 34.63 mg/L, the phosphorus concentration varied from 8.21 mg/L to 10.25 mg/L, the ester content ranged between 91.87% and 98.34%, and the alkali metals varied from 2.143 mg/L to 3.428 mg/L. All biodiesel produced fromthe pre-harvest treated kernels met the EN-ISO 12185 and EN 14213 standards for densities and ester contents, respectively. It was observed that the T2 and T3 acid values were 0.871% and 0.695%, respectively, while the T4 and T5 acid values were 1.033% and 1.118%, respectively, and all failed to meet both ASTM and EN standards, though the organically produced kernel’s biodiesels had better prospects. Furthermore, it was observed that the iodine values of the biodiesels, obtained from the five treatment plans, were within the EN 14214 approved standards for biodiesel. The findings portrayed that the organic manure had a more positive impact on the groundnut kernels, compared to groundnut grown with fertilizers. As observed from the results, the biodiesel produced from the organic kernels hada better fuel quality than that acquired from the convectional kernels.

Production of Biodiesel by Transesterification of Pilot Plant Waste over Nickel (Ni)/Eggshell (CaO) Catalyst

The increment of pilot plant waste at UniKL MICET and eggshell waste cause disposal problems, such as the water and soil pollution, human health concerns, and disruption to aquatic ecosystems. Thus, to reduce the effect of disposal problem to the environment, pilot plant waste is converted into biodiesel, while eggshell is converted into catalyst in this study. This paper reports on the effect of catalyst preparation method and reaction temperature on biodiesel yield and quality. Transesterification process of pilot plant waste (olein and stearin) was conducted by using Ni/CaO (eggshell) catalyst from different preparation methods at different reaction temperatures (328 K, 333 K, 338 K and constant reaction time (5 hours), methanol-to-oil ratio (15:1), and weight of catalyst (8 wt%). The catalysts were synthesized via wet impregnation and sol–gel method and its physicochemical properties were subsequently characterized by TGA and FTIR analysis. Biodiesel analysis was done using GCMS and FTIR, while the physical properties (density, flash point, and kinematic viscosity) of biodiesel were measured according to ASTM D6751. Kissinger-Akahira-Sunose (KAS) kinetic model shows that the catalyst prepared by wet impregnation method has the lowest activation energy, which was 81.48 kJ mol–1. In addition, GCMS analysis shows that reaction temperature at 338 K produced the highest yield of biodiesel (88.26%). In conclusion, the best catalyst preparation method was wet impregnation method and the best reaction temperature was 338 K. In addition, the physical properties of the produced biodiesel corresponded to ASTM standard, thereby indicating high quality of biodiesel and can be used as petroleum-diesel substitute.

Characterization of homogenous acid catalyzed biodiesel production from palm oil: experimental investigation and numerical simulation.

Biodiesel is a biological renewable source produced from the conversion of triglycerides to alkyl esters. Palm oil is one of the most used lipid feedstocks for biodiesel production. It becomes necessary to optimize the transesterification reaction parameters to reduce the cost and enhance the quality of biodiesel. This study focuses on the use of homogenous sulfuric acid as a catalyst for the transesterification of palm fatty acids to methyl esters in a batch-scale reactor. A novel examination of transesterification reaction input parameters using the technique for order performance by similarity to ideal solution optimization technique and the effect of these parameters on yield, viscosity, and density of palm biodiesel using 3D surface graphs is investigated in this research. The present optimization approach is implemented to find out the optimum ranking of biodiesel production. From the experimental and numerical simulation, optimum results were observed at the catalyst concentration of 6% (w/w), reaction temperature of 70°C, the reaction time of 120min, and alcohol to oil molar ratio of 30:1 at which yield of 95.35%, viscosity of 5.0 cSt, and density of 880kg/m3 of palm biodiesel were obtained. The different physicochemical properties of produced palm methyl esters are obtained within standards set by international authorities. Selected optimized process parameters can be used for commercial-scale biodiesel production.

Effect of DEE added Karanja biodiesel fuel on the performance, combustion and emission characteristics of CI engine under variable injection timing and engine load

The higher density and viscosity of biodiesel reduce the engine's performance due to poor atomisation. The present study aims to investigate the effect of DEE and injection time on engine characteristics fueled with KME-diesel blends. For this purpose, single cylinder CI engine is used. The injection timing is advanced and retarded by 2° from the base injection timing (27° bTDC), and the load is varied from 0% to 100%. The addition of DEE to the blends results in a reduction of density and viscosity. At 29° bTDC, the brake thermal efficiency for 5% DEE is increased by 3.1% compared to a blend without DEE at full load. For 5% DEE, compared to 27° bTDC, 29° bTDC reduces the HC and CO emission by 4.5% and 42.8%, respectively at full load. It is concluded that the 5% DEE operating at 29° bTDC improves the engine's performance with a small rise in NOX emission. Highlights DEE added biodiesel blend has lower viscosity and density than biodiesel. 5% DEE addition in biodiesel blend at advanced injection timing improves BTE and reduces emission. Lower in-cylinder temperature is achieved due to higher latent heat of evaporation. The CO and HC emissions for B25DE5 at 29° bTDC are reduced by 4.5% and 42.8% than 27° bTDC at full load. At advanced injection timing NOX emission for 5% DEE addition increased by 2.7% than 27° bTDC.

Effect of Fuel Preheating on Engine Characteristics of Waste Animal Fat-Oil Biodiesel in Compression Ignition Engine.

The present study aims at understanding the effects of fuel preheating on engine characteristics of waste animal fat-oil (WAF-O) biodiesel in a single-cylinder CI engine, with the preheating technique proposed as an effective means for enhancing the fuel properties. To understand the effects of the preheated fuel, the WAF-O biodiesel was preheated at 60, 80, 100 and 120 °C and tested along with neat diesel and unheated WAF-O biodiesel. For this purpose, biodiesel was produced from different animal wastes by means of KOH-assisted ethanol-based transesterification, reporting its maximum yield as 96.37 ± 1.8%, with significant distribution of unsaturated oleic acid, saturated palmitic acid and stearic acid. Upon evaluating its fuel characteristics as per ASTM D6751 standards, a rise in preheating temperature by 1 °C reduced the density and kinematic viscosity of WAF-O biodiesel by 0.383 kg/m3 and 0.025 mm2/s, respectively, and was explained by the weakening of intermolecular forces between its fatty acid ester molecules. Preheated samples reported superior combustion characteristics by exhibiting increased in-cylinder pressure (2.24%, on average) and heat release rates in addition to their shortened ignition delay (1–4 °CA). Furthermore, preheating of WAF-O biodiesel reduced its specific fuel consumption and increased its brake thermal efficiency by 7.86% (on average) and 9.23% (on average), respectively. However, higher preheating temperatures (>120 °C) resulted in increased fuel consumption owing to its varied flow characteristics. In addition to the changes in combustion characteristics, preheating WAF-O bio-diesel also resulted in reduced carbon monoxide, nitrous oxide and hydrocarbon emission by 13.88%, 7.21% and 26.94%, respectively, and increased carbon dioxide emission by 7.58%. Summing up, the enhancements in overall engine characteristics of preheated samples were accounted for by their improvised fuel injection characteristics due to their reduced density and viscosity, which ensured for their effective combustion.

ИЗМЕНЕНИЕ ФИЗИКО-ХИМИЧЕСКИХ ХАРАКТЕРИСТИК БИОДИЗЕЛЬНОГО ТОПЛИВА И ЕГО КОМПОЗИЦИЙ ПРИ ХРАНЕНИИ

Alternative fuels, primarily synthesized from renewable plant materials, are becoming increasingly important. The standards that regulate the characteristics of modern environmentally friendly diesel fuel allow the addition of 6 to 20% of biodiesel fuel synthesized from renewable plant or animal feedstock to petroleum fuel. This additive allows not only to reduce the emission of harmful substances with exhaust gases, but also to increase the cetane number and lubricity of modern fuels with a low content of sulfur and aromatic compounds. The changes in physicochemical characteristics that occur during storage of biodiesel fuel have been studied on the example of biodiesel fuels synthesized from camelina and flax oils. It is shown that the density and viscosity of biodiesel fuel increase during storage in polyethylene and metal tanks, and to a greater extent during storage in a metal tank. It has been established that the viscosity (3.5-5.0 mm2 /s) and density (860-900 kg/m3 ) of biodiesel fuel is stored within the normalized limits for 7 months in a polyethylene tank; and the shelf life is reduced to 4-5 months in metal tank. The reason for the deterioration of fuel quality are oxidation and polymerization processes. Additives belong to a homologous series of sterically hindered phenols containing an azo group have been proposed for stabilization. Studies of the storage process of compositions of petroleum and biodiesel fuels containing from 10 to 70% (vol.) of the latter (B10 - B70) have been carried out. It has been established that stratification of fuel compositions occurs in addition to an increase in density and viscosity during storage. In this case, compositions with a low content of biodiesel fuel are stratified first. 50% and 40% of biodiesel fuel flaked off in compositions B10 and B20, respectively, for 5 months; the process began already after 30 and 60 days of storage. In composition B50, stratification started only after 4 months of storage; only 4% of the biodiesel fuel flaked off by the end of the fifth month. No stratification was observed for composition B70. The stratification may be due to weak intermolecular interactions between petroleum hydrocarbons and biodiesel molecules containing polar ester groups; as well as with the destruction of the colloidal structure of fuels.