Biodiesel In Terms Research Articles

The Effect of Titanium Tetrahedral Coordination of Silica-Titania Catalyst on the Physical Properties of Biodiesel

This study investigates the correlation of the number of titanium tetrahedral coordination and biodiesel production. The solid-state method has been used to synthesis of silica-titania catalyst for biodiesel production, which the precursors, i.e. silica and titania commercials were heated in the temperature range of 450 - 550°C. The characterization of the prepared silica-titania has been studied by FTIR and DR UV-Vis in order to identify and calculate the presence of titanium tetrahedral coordination in silica-titania catalyst. A very small peak at around 950 cm-1 indicated the presence of titanium tetrahedral coordination through Si–O–Ti bonds. Deconvolution of DR UV-Vis spectra showed the coordination of titanium in silica-titania is more octahedral. However, the number of titanium tetrahedral coordination of the prepared silica-titania is found higher than that of TiO2 commercial. The increasing of titanium tetrahedral fraction in silica-titania affects the physical properties of biodiesel in terms of boiling point, viscosity and density, which is produced by the reaction of methanol and palm oil.

Structural effects of biodiesel on soot formation in a laminar coflow diffusion flame

Structural effects of biodiesel in terms of unsaturation, i.e. C=C double bonds, its position and the presence of the ester moiety on soot formation are studied in this paper. Laminar coflow diffusion flames of 5-decene, 1-decene, n-decane, and a biodiesel surrogate consisting of a 50%/50% molar blend of n-decane and methyl-octanoate are selected for the investigation. It is observed that the presence of unsaturation promotes soot formation in the flames by increasing soot chemical surface growth species and soot inception species (aromatics) as it is evident from the larger primary particle size and number density of soot particles in the 1-decene, and 5-decene flames compared to the n-decane flame, respectively. More centrally located C=C double bond further speeds up soot inception as it promotes the formation of aromatic species. This is also evident from earlier detection of soot on the centerline and higher soot primary particle number density of the 5-decene flame compared to 1-decene and n-decane flames measured by the laser extinction and thermophoretic sampling methods, respectively. Effects of the ester moiety on soot formation are more on the concentrations of soot chemical surface growth species because the biodiesel surrogate flame has similar number density of primary particles compared to the n-decane flame but soot primary particles have smaller diameters.

Microalga Nannochloropsis sp. Biomass for Biodiesel Production: Conventional (Cell Disruption) and in situ Transesterification

The potential of Nannochloropsis sp. microalga to biodiesel production was assessed. The work deals with the optimization of the cell disruption, a required step when the lipid extraction followed by the transesterification reaction is the option to produce biodiesel, as well as the optimization of the reaction parameters (catalyst, alcohol, temperature and time) of the in situ transesterification (direct conversion of the saponifiable lipids into FAME - fatty acid metyl esters, usually called as biodiesel, in one step). The cell rupture of wet and dried biomass (by oven and freezedryer) using different methods (physical - coffee grinder and ball-mill; and thermodynamic - microwaves and autoclave) was evaluated. The highest lipid recovery (42.4 ± 0.2% g of lipids /g of oven dried biomass) was attained from the oven dried biomass pretreated in a coffee grinder followed by a ball milling. The microalgal oil quality (fatty acid profile, acid value and iodine value) was determined and was not influenced by the biomass state (oven or freeze-dried) nor by the cell rupture method, being mainly composed of palmitic (C16:0), palmitoleic (C16:1) and oleic (C18:1) acids. The linoleic acid (C18:3) content is quite low (< 0.35% w/w) which results in a high quality biodiesel in terms of this parameter. The viability of the in situ transesterification, in order to reduce technological challenges, energy, time, environmental negative impacts and costs of the traditional processes, was studied and optimized The most favourable conditions were found to be 3.16 g of methanol / 100 g of dry biomass, 1.2% v/v of catalyst (H2SO4), for 6 h at 50°C, which allows of 95% esters formation. In terms of the cell rupture, the coffee grinder followed by the ball mill, proved again, to be the most efficient process, promoting an increase in the transesterification reaction rate.

Experimental investigations on the increase in nitric oxide emissions using biodiesels and their mitigation

One of the major shortcomings to be addressed in the widespread applications of biodiesel fuel for compression ignition engines is the formation of higher nitric oxide emissions. It is well established in the literature that thermal nitric oxide is a dominant source for nitric oxide formation in engines. Thermal nitric oxide formation increases by any in-cylinder combustion strategy that alters the in-cylinder temperatures, the oxygen fraction or the residence time of high-temperature post-flame burned gases. The differences between the properties of biodiesel in terms of a higher bulk modulus, a higher cetane number and the presence of a fuel-bound oxygen fraction and the properties of diesel are found to affect the in-cylinder charge conditions and thus the nitric oxide formation. The present work aims to understand the major contributor to the higher nitric oxide formation with biodiesel based on experimental investigations in two different engine configurations: one with a conventional mechanical-type injection system and the other with a modern common-rail direct-injection system. The experimental results highlight that the dynamic injection timing advanced up to a maximum of 2.6° crank angle owing to the higher bulk modulus of biodiesel. This factor contributes to specific nitric oxide emissions which are 7.5% higher in an engine having a mechanical-type injection system. The increase in the nitric oxide is neutralized on restoring the injection timing to that of the diesel injection time setting. In the case of an engine with a modern common-rail direct-injection system, the injection timings remain unaltered, and the nitric oxide concentrations for diesel and for biodiesel–diesel blends also remains the same.

Biodiesel: Fuel for the Future (A Brief Review)

Several attempts have been made by researchers across the globe to counter the effects of the growing informat ion related to the finite nature of the present fossil fuel reserve and the associated hazards. Biofuel has gained global popularity in this respect as a biomass based fuel that have been tipped as a timely candidate. This review strictly focuses on biodiesel of all b io mass derived biofuel.The major feedstock and their supply lines in a b id to create a balance between food and energy was considered. Various catalyst used including biocatalyst for the simp le trans-esterification react ion of the feedstock (Vegetable/Used Oil; Edible/Inedib le Oil and Alcohol) were analyzed. In fluence of the feedstock mo lar rat io, temperature and t ime of the reaction on the conversion/yield and product purity and quality were equally reviewed. The thermo -kinetics of the biodiesel production, fuel properties of biodiesel and the trials subjected to biodiesel in terms of workab ility were considered for review in th is paper.

Effects of open combustion chamber geometries on the performance of pongamia biodiesel in a DI diesel engine

The present work investigates the effect of varying the combustion chamber geometry on the performance of a diesel engine using biodiesel in terms of brake specific fuel consumption, brake thermal efficiency as well as exhaust emissions and combustion characteristics. Engine tests have been carried out using a blend of 20% Pongamia Oil Methyl Ester (POME) with standard diesel as fuel and with three types of combustion chambers namely Hemispherical combustion chamber, Toroidal combustion chamber and Shallow depth combustion chamber without altering the compression ratio of the engine. The test results showed that brake thermal efficiency for toroidal combustion chamber is higher than for the other two types of combustion chambers. Significant improvement in reduction of particulates, carbon monoxide and unburnt hydrocarbons is observed for toroidal combustion chamber compared to the other two. However oxides of nitrogen were slightly higher for toroidal combustion chamber. The combustion analysis shows improved characteristics for toroidal combustion chamber compared to baseline engine at all loads of operation.

Characterization of the acylglycerols and resulting biodiesel derived from vegetable oil and microalgae (Thalassiosira pseudonana and Phaeodactylum tricornutum)

Algal biofuels are a growing interest worldwide due to their potential in terms of sustainable greenhouse gas displacement and energy production. This article describes a comparative survey of biodiesel production and conversion yields of biodiesel via alkaline transesterification of acylglycerols extracted from the microalgae Thalassiosira pseudonana and Phaeodactylum tricornutum, grown under silicate or nitrate limitation, and that of model vegetable oils: soybean, and rapeseed oil. Acylglycerols were extracted with n-hexane and the total yield per biomass was determined by gravimetric assay. Under our conditions, the total acylglycerol yield from the microalgae studied was 13-18% of total dry weight. The biodiesel samples were analyzed using gas chromatography-flame ionization detector to determine quantitative information of residual glycerol, mono-, di-, and tri-acylglycerol concentrations in the biodiesel. All of the algal-based biodiesel demonstrated less mono-, di-, and tri-acylglycerol concentrations than the vegetable-based biodiesel under identical transesterification conditions. The fatty acid compositions of all the feedstock oils and their resultant biodiesel were also analyzed and reported. Based on the fatty acid methyl ester compositions of our samples we qualitatively assessed the suitability of the algal-derived biodiesel in terms of cetane number (CN), cold-flow properties, and oxidative stability.

Rapid and precise estimation of biodiesel by high performance thin layer chromatography

Various sophisticated chromatographic techniques employing gas chromatography (GC) and high performance liquid chromatography (HPLC) were used to quantify biodiesel in terms of conversion percentage of the oil feedstock. These techniques are time consuming. In the present study, a rapid and reproducible technique was developed using high performance thin layer chromatography (HPTLC) for the accurate quantification of the conversion percentage of triglycerides into biodiesel (fatty acid methyl esters/FAME). The oil substrate was transesterified by a conventional process using alkali catalyst. The monoglycerides, diglycerides, unreacted triglycerides, free fatty acid and biodiesel (FAME) product were analyzed by HPTLC. An absorption maximum of the mixture of standard methyl esters was determined to be 203.5 nm by spectroscopic scan. The conversion percentage was calculated from the corresponding peak areas of the glycerides and biodiesel product, separated on thin layer chromatography using hexane, ethyl acetate and acetic acid (9:1:0.1) as mobile phase. In terms of reproducibility and precision of data and also the ease and quickness of simultaneous processing, HPTLC based analysis and quantification of biodiesel (FAME) proved to be an alternative to other conventional analytical techniques like GC and HPLC.

Partial hydrogenation of methyl esters of sunflower oil catalyzed by highly active rhodium sulfonated triphenylphosphite complexes

Abstract The partial hydrogenation of polyunsaturated methyl esters of sunflower oil to monounsaturated methyl esters catalyzed by highly active rhodium sulfonated phosphite (Rh/STPP) complexes was studied in order to improve the quality of biodiesel in terms of increased oxidative stability and higher cetane numbers. The hydrogenation reaction proceeds under mild conditions and high catalytic activities (TOF = 38,000 h −1 ) were achieved employing Rh/STPP catalysts at a P/Rh molar ratio of 4 at 30–130 °C, 10–70 bar hydrogen partial pressure and molar ratios of C C/Rh between 700 and 6000 within 5–60 min of reaction time in conventional organic media.

The effects of turbocharger on the performance and exhaust emissions of a diesel engine fuelled with biodiesel

This paper investigates the effects of turbocharger on the performance of a diesel engine using diesel fuel and biodiesel in terms of brake power, torque, brake specific consumption and thermal efficiency, as well as CO and NO x emissions. For this aim, a naturally aspirated four-stroke direct injection diesel engine was tested with diesel fuel and neat biodiesel, which is rapeseed oil methyl ester, at full load conditions at the speeds between 1200 and 2400 rpm with intervals of 200 rpm. Then, a turbocharger system was installed on the engine and the tests were repeated for both fuel cases. The evaluation of experimental data showed that the brake thermal efficiency of biodiesel was slightly higher than that of diesel fuel in both naturally aspirated and turbocharged conditions, while biodiesel yielded slightly lower brake power and torque along with higher fuel consumption values. It was also observed that emissions of CO in the operations with biodiesel were lower than those in the operations with diesel fuel, whereas NO x emission in biodiesel operation was higher. This study reveals that the use of biodiesel improves the performance parameters and decreases CO emissions of the turbocharged engine compared to diesel fuel.

Transesterification of karanja (Pongamia pinnata) oil by solid basic catalysts

The transesterification of karanja oil with methanol was carried out using solid basic catalysts. Alkali metal-impregnated calcium oxide catalysts, due to their strong basicity, catalyze the transesterification of triacylglycerols. The alkali metal (Li, Na, K)-doped calcium oxide catalysts were prepared and used for the transesterification of karanja oil containing 0.48-5.75% of free fatty acids (FFA). The reaction conditions, such as catalyst concentration, reaction temperature and molar ratio of methanol/oil, were optimized with the solid basic Li/CaO catalyst. This catalyst, at a concentration of 2 wt-%, resulted in 94.9 wt-% of methyl esters in 8 h at a reaction temperature of 65 °C and a 12 : 1 molar ratio of methanol to oil, during methanolysis of karanja oil having 1.45% FFA. The yield of methyl esters decreased from 94.9 to 90.3 wt-% when the FFA content of karanja oil was increased from 0.48 to 5.75%. The performance of this catalyst was not significantly affected in the presence of a high FFA content up to 5.75%. The catalytic activities of Na/CaO and K/CaO were also studied at the optimized reaction conditions. In these two cases, the reaction initially proceeds slowly, however, leading to similar yields as in the case of Li/CaO after 8 h of reaction time. The purified karanja methyl esters have an acid value of 0.36 mg KOH/g and an ester content of 98.6 wt-%, which satisfy the American as well as the European specifications for biodiesel in terms of acid value and ester content.