Investigation of biodiesel production methods by altering free fatty acid content in vegetable oils

Abstract: The variations in biodiesel composition based on the feedstock used for its production result in significant variations in the fuel properties and thereby, engine characteristics. This necessitates the need for adopting a composition based approach to analyze biodiesel fuel properties and engine characteristics. Based on this premise, biodiesel composition based multi linear regression models are proposed in the present work to predict the density, kinematic viscosity and surface tension of biodiesel. Biodiesel composition effects are captured through two new parameters, namely straight chain saturation factor (SCSF) and modified degree of unsaturation (DUm) which represents the effects of saturated and unsaturated methyl ester constituents of biodiesel, respectively. SCSF and DUm are found to better capture the effects of biodiesel composition as compared to the parameters available in the literature, namely long chain saturated factor, modified long chain saturated factor and degree of unsaturation by addressing their limitations. The proposed models also account for the effects of temperature on the variations of biodiesel properties. To train and validate the proposed multi linear regression models, the density and kinematic viscosity in the temperature range of 293 to 373 K and surface tension in the temperature range of 303 to 353 K of seven biodiesels having significantly different composition are measured. For validation, the measured property data of three additional biodiesels not considered in training the models are used. The predictions compared well with measured data with regression coefficients of 0.98, 0.97 and 0.93 and mean absolute percentage error of 6.28, 0.36 and 1.4 percent for kinematic viscosity, density and surface tension, respectively. Statistical analysis carried out using ANOVA revealed a strong correlation between biodiesel composition based parameters, SCSF and DUm and aforementioned properties. Further, DUm is found to have a profound influence on the kinematic viscosity and density of biodiesel as compared to SCSF while its effects on the surface tension are statistically insignificant.

Abstract: Simplex lattice design has been implemented for hybridization, processing and optimization, to have a relevant blend of oils for biodiesel synthesis. The study was done to check the impacts of starting oil amount on kinematic viscosity, density, cetane number and higher calorific value of hybrid oil in view of it use as biodiesel feedstock. Models significance is statistically assessed by analysis of variance. Based on superposition approach of the potential results, numerical optimization was done followed by Gas Chromatography-Mass Spectroscopy (GC–MS) for identification of compound. With desirability factor 0.790, the optimized formulation has high similarities among actual and predicted responses. Optimal composition suggested for the hybrid oil was 49.82 g WKO, 24.67 g NMO and 50.51 g SHB. GC–MS analysis result showed that hybrid feedstock contains 35.45% oleic acid, 28.13% linoleic acid and 18.24% palmitic acid. The determined fuel properties fitted well with the ASTM D6751 and EN 14214 specifications for biodiesel.

Abstract: Monoalkyl ester of vegetable oil, animal fat, and used cooking oil (UCO) is termed as biodiesel. Biodiesel obtained from UCO is gaining importance as an alternate fuel for usage in diesel e...

Abstract: A significant obstacle to utilize biodiesel fuel for automotive engine applications is its poor oxidative stability. In the present work, oxidation and spray characteristics of Karanja biodiesel stored for one year are studied. The fuel physical properties that influence the spray characteristics, viz. density, kinematic viscosity, and surface tension, are increased by 0.38%, 12.74%, and 3.95%, respectively, after a one-year storage period. The macroscopic spray characteristics of fresh and aged Karanja biodiesels are compared with that of diesel. The spray penetration length, spray cone angle, and the projected spray area are measured at chamber pressures of 20, 30, and 40 bar and injection pressures of 300, 600, and 900 bar. The results showed reduced mass flow rate at lower injection pressures with fresh and aged biodiesels than diesel. At 300 bar injection pressure, spray penetration length is longer with diesel during the initial injection period, but later the spray slows down. There are no appreciable differences in the spray penetration length and the spray cone angle between diesel, fresh, and aged biodiesels at all the injection pressures. The projected spray area is higher for diesel than biodiesels indicating a denser spray with biodiesels. The study concludes that although biodiesel's long-term storage results in variations in physical and chemical properties, there are no significant variations in the macroscopic spray characteristics. Analysis of atomization characteristics of fresh and aged biodiesels also revealed similar results.

Abstract: In this study, the components of Terminalia chebula plant such as leaves and seeds are effectively utilized as a green source for the synthesis of copper oxide nanoparticles (CuO NPs) and production of biodiesel, respectively. CuO NPs have been synthesized through solution combustion route using T. chebula leaves extract as a reducing-cum-fuel agent. Notably, the synthesized CuO NPs are used as a heterogeneous catalyst in the biodiesel production. The synthesized CuO NPs are characterized using XRD, FTIR, FESEM, BET, Zeta potential, DLS and UV–visible absorption spectroscopy. The obtained results showed the monoclinic crystal structure of CuO with rod-like morphology with diameter of around 100 nm. The CuO NPs were successfully utilized for the biodiesel synthesis using T. chebula oil as feedstock by varying the reaction parameters. The maximum of 97.1% yield of T. chebula methyl ester (TCME) is achieved at 3 wt% catalyst loading with methanol to oil molar ratio of 9:1 for the reaction time of 60 min at the of temperature 60 °C with constant stirring speed of 650 rpm. The CuO NPs showed a good catalytic stability up to four cycles with a slight loss in biodiesel yield. The kinetic study of TCME production fits well to the pseudo-first order reaction and the activation energy (Ea) and frequency factor (A) is found to be 40.74 kJ/mol and 5.7 × 104 min−1 respectively. Further, the TCME is also characterized by 1H NMR and FTIR. The fuel properties of TCME are also determined and found to be in the range of ASTM standards. The green chemistry metrics such as E-factor, atom economy, atom efficiency and solvent and catalyst environmental impact parameter have also been studied. Furthermore, the performance, combustion and emission characteristics of the test samples (diesel, biodiesel test blends such as B10, B20, B30, B40 and B100) on a single cylinder diesel engine have also been studied by varying the load (0%, 25%, 50%, 75% and 100%).

Abstract: Biodiesel has become more attractive recently because of its environmental benefits and the fact that it is made from renewable resources. The cost of biodiesel, however, is the main hurdle to commercialization of the product. The used cooking oils are used as raw material, adaption of continuous transesterification process and recovery of high quality glycerol from biodiesel by-product (glycerol) are primary options to be considered to lower the cost of biodiesel. There are four primary ways to make biodiesel, direct use and blending, microemulsions, thermal cracking (pyrolysis) and transesterification. The most commonly used method is transesterification of vegetable oils and animal fats. The transesterification reaction is aAected by molar ratio of glycerides to alcohol, catalysts, reaction temperature, reaction time and free fatty acids and water content of oils or fats. The mechanism and kinetics of the transesterification show how the reaction occurs and progresses. The processes of transesterification and its downstream operations are also addressed. ” 1999 Published by Elsevier Science B.V. All rights reserved.

Abstract: Biodiesel (fatty acid methyl esters), which is derived from triglycerides by transesterification with methanol, has attracted considerable attention during the past decade as a renewable, biodegradable, and nontoxic fuel. Several processes for biodiesel fuel production have been developed, among which transesterification using alkali-catalysis gives high levels of conversion of triglycerides to their corresponding methyl esters in short reaction times. This process has therefore been widely utilized for biodiesel fuel production in a number of countries. Recently, enzymatic transesterification using lipase has become more attractive for biodiesel fuel production, since the glycerol produced as a by-product can easily be recovered and the purification of fatty methyl esters is simple to accomplish. The main hurdle to the commercialization of this system is the cost of lipase production. As a means of reducing the cost, the use of whole cell biocatalysts immobilized within biomass support particles is significantly advantageous since immobilization can be achieved spontaneously during batch cultivation, and in addition, no purification is necessary. The lipase production cost can be further lowered using genetic engineering technology, such as by developing lipases with high levels of expression and/or stability towards methanol. Hence, whole cell biocatalysts appear to have great potential for industrial application.

Abstract: Biodiesel is an alternative diesel fuel that is produced from vegetable oils and animal fats. It consists of the monoalkyl esters formed by a catalyzed reaction of the triglycerides in the oil or fat with a simple monohydric alcohol. The reaction conditions generally involve a trade-off between reaction time and temperature as reaction completeness is the most critical fuel quality parameter. Much of the process complexity originates from contaminants in the feedstock, such as water and free fatty acids, or impurities in the final product, such as methanol, free glycerol, and soap. Processes have been developed to produce biodiesel from high free fatty acid feedstocks, such as recycled restaurant grease, animal fats, and soapstock.

Abstract: Biodiesel is synthesized via the transesterification of lipid feedstocks with low molecular weight alcohols. Currently, alkaline bases are used to catalyze the reaction. These catalysts require anhydrous conditions and feedstocks with low levels of free fatty acids (FFAs). Inexpensive feedstocks containing high levels of FFAs cannot be directly used with the base catalysts currently employed. Strong liquid acid catalysts are less sensitive to FFAs and can simultaneously conduct esterification and transesterification. However, they are slower and necessitate higher reaction temperatures. Nonetheless, acid-catalyzed processes could produce biodiesel from low-cost feedstocks, lowering production costs. Better yet, if solid acid catalysts could replace liquid acids, the corrosion and environmental problems associated with them could be avoided and product purification protocols reduced, significantly simplifying biodiesel production and reducing cost. This article reviews some of the research related to biodi...

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