Theoretical modeling of iodine value and saponification value of biodiesel fuels from their fatty acid composition

Biodiesel is an alternative fuel consisting of alkyl esters of fatty acids from vegetable oils or animal fats. The properties of biodiesel depend on the type of vegetable oil used for the transesterification process. The objective of the present work is to theoretically predict the iodine value and the saponification value of different biodiesels from their fatty acid methyl ester composition. The fatty acid ester compositions and the above values of different biodiesels were taken from the available published data. A multiple linear regression model was developed to predict the iodine value and saponification value of different biodiesels. The predicted results showed that the prediction errors were less than 3.4% compared to the available published data. The predicted values were also verified by substituting in the available published model which was developed to predict the higher heating values of biodiesel fuels from their iodine value and the saponification value. The resulting heating values of biodiesels were then compared with the published heating values and reported.     

Characterization and transesterification of Iranian bitter almond oil for biodiesel production

In the present work the production of biodiesel using bitter almond oil (BAO) in a potassium hydroxide catalyzed transesterification reaction was investigated. The BAO was obtained from resources available in Iran and its physical and chemical properties including iodine value, acid value, density, kinematic viscosity, fatty acid composition and mean molecular weight were specified. The low acid value of BAO (0.24 mg KOH/g) indicated that the pretreatment of raw oil with acid was not required. The fatty acid content analysis confirmed that the contribution of unsaturated fatty acids in the BAO is high (84.7 wt.%). Effect of different parameters including methanol to oil molar ratio (3–11 mol/mol), potassium hydroxide concentration (0.1–1.7% w/w) and reaction temperature (30–70 °C) on the production of biodiesel were investigated. The results indicated that these parameters were important factors affecting the tranesterification reaction. The fuel properties of biodiesel including iodine value, acid value, density, kinematic viscosity, saponification value, cetane number, flash point, cloud point, pour point and distillation characteristics were measured. The properties were compared with those of petroleum diesel, EN 14214 and ASTM 6751 biodiesel standards and an acceptable agreement was observed.     

Fuel properties of biodiesel from vegetable oils and oil mixtures. Influence of methyl esters distribution

In this work, the quality of biodiesel produced by basic transesterification from several vegetable oils (soybean, rapeseed, sunflower, high oleic sunflower, Cynara Cardunculus L., Brassica Carinata and Jatropha Curca) cultivated in Extremadura has been studied in detail. The influence of raw material composition on properties such as density, viscosity, cetane number, higher heating value, iodine and saponification values and cold filter plugging point has been verified. Other biodiesel properties such as acid value, water content and flash and combustion points were more dependent on characteristics of production process. Biodiesel produced by rapeseed, sunflower and high oleic sunflower oils transesterification have been biofuels with better properties according to Norm EN 14214. Finally, it has been tested that it is possible to use oils mixtures in biodiesel production in order to improve the biodiesel quality. In addition, with the same process conditions and knowing properties of biodiesel from pure oils; for biodiesel from oils mixtures, its methyl esters content, and therefore properties dependent this content can be predicted from a simple mathematical equation proposed in this work.     

Renewable energy sources from Michelia champaca and Garcinia indica seed oils: A rich source of oil

Michelia champaca and Garcinia indica seeds yielded 45.0% and 45.5% of oil. The fatty acid profiles of both the seed oils were examined. The saponification value (SV), iodine value (IV) and cetane number (CN) of fatty acid methyl esters of both the seed oils were empirically determined. The saponification value (SV) and iodine value (IV) are in good agreement with the experimentally observed values. The fatty acid compositions, iodine value and cetane number were used to predict the quality of fatty acid methyl esters of oil for use as biodiesel. Thus, the fatty acid methyl esters of seed oils of M. champaca and G. indica were found to be the most suitable biodiesel and they meet the major specification of biodiesel standards. The selected plants M. champaca and G. indica have great potential for biodiesel. M. champaca and G. indica seed oils were found to contain keto fatty acids along with the other normal fatty acids, respectively. These fatty acids have been detected and characterized by UV, FTIR, ¹H NMR, ¹³C NMR, MS, GC techniques and chemical transformations.     

Unique occurrence of unusual fatty acid in the seed oil of Aegle marmelos Corre: Screening the rich source of seed oil for bio-energy production

In this work, an attempt has been made to characterize, isolate and elucidate the structure of unusual fatty acid in the seed oil of Aegle marmelos Corre. Further, this nonedible seed oil is screened for its bio-diesel or industrial feedstock property. The Aegle marmelos Corre seeds yielded 49.0% oil. The seed oil contains 12.5% of 12-hydroxyoctadec-cis-9-enoic acid (ricinoleic acid) along with other normal fatty acids. The identification and characterization was supported by FTIR, ¹H NMR, ¹³C NMR, MS, GC analysis and chemical degradation technique. A good agreement is seen between the calculated and experimental results of iodine value (IV) and saponification value (SV). The prominent parameters of bio-diesel such as cetane number (CN), lower heating value (LHV) and higher heating value (HHV) are deployed to envisage the quality of oil for use as bio-diesel. This seed oil is nonedible and is found to be the alternative feed stock for the production of bio-diesel since it convenes the major specifications of bio-diesel. The bio-diesel property of fatty acid methyl esters (FAMEs) of this seed oil is compared with other bio-diesels.     

Bio-oil extraction and physicochemical characterization of Caesalpinia pulcherrima plant seed oil

Dwarf Poinciana (Caesalpinia pulcherrima) seeds are studied for first time for the extraction of bio-oil. The dried and crushed seeds are optimized for maximum yield of bio-oil with a series of polar and nonpolar solvents and recovered by a simple distillation process. Methanol is found to yield the maximum bio-oil. The fatty acid analysis of bio-oil reveals the prevalence of linoleic acid (54.67%), followed by palmitic acid (16.9%), stearic acid (12.5%), and oleic acid (10.32%). Basic fuel properties like specific gravity, viscosity, refractive index, iodine value, saponification value, fire point, flash point, pour point, and calorific value are studied.     

Biophysicochemical evaluation and micropropagation study of Jatropha curcas and Ricinus communis for biodiesel production

The upcoming energy sources of Jatropha curcas and Ricinus communis promise to mitigate the energy crisis and environmental pollution belonging to the Euphorbiaceae family. Both of them have been researched in terms of availability, cost, and biochemical parameters. The seed oils of various jatropha and castor biotypes were screened out and evaluated for their physiochemical parameters viz. oil content (34–49%), biodiesel yield (30–81%), density (0.875–0.971 g/cm³), viscosity (0.6032–2.004 mm³/s), iodine value (75–450.45 mg/g), free fatty acid value (0.986–3.400 mg/g), saponification value (59.29–93.79 mg/g), flash point (133–218°C), fire point (163–262°C), fatty acid composition, and ash content (0.065–0.398%), and were estimated for comparison between jatropha and castor biotypes. Various combinations of auxins with cytokinins were used for a regeneration study. The best shoot regeneration (70%) was observed in MS medium supplemented with NAA (0.5 ppm) and BAP (2.5 ppm). Root induction (95%) was successfully obtained in plane MS. Acclimatization and hardening was quite successful with a survival rate of 70%.     

Variability in sunflower oil quality for biodiesel production: A simulation study

Biodiesel is an alternative fuel made from vegetable oils or animal fats. The fatty acid composition of the feedstock, which varies among and within species, is the main determinant of biodiesel quality. In this work we analyze the variability in biodiesel quality (density, kinematic viscosity, heating value, cetane number and iodine value) obtained from sunflower oil, by means of a validated crop model that predicts the fatty acid composition of one high-oleic, and three traditional (high-linoleic) sunflower hybrids. The model was run with a 10-year average weather data from 56 weather stations in Argentina, and simulation results were compared to the biodiesel standards of Argentina, USA and Europe. We show that biodiesel produced from sunflower oil does not have one fixed quality, but different qualities depending on weather conditions and agricultural practices, and that intraspecific variation in biodiesel quality can be larger than interspecific differences. Our results suggest that (a) sunflower oil from high-oleic hybrids is suitable for biodiesel production (within limits of all analyzed standards), regardless of growing conditions and (b) sunflower oil from traditional hybrids is suitable for biodiesel production under the standards of Argentina and USA, while only certain hybrids grown in warm regions (e.g., Northern Argentina, Southern USA, China, India, Pakistan) are suitable for biodiesel production according to the European standard.     

Effect of natural,accelerated and saturated salt accelerated aging on the Jatropha curcas L. seeds in optimizing the yield of seed oil as feedstock for biodiesel

Uninterrupted and good quality of feedstock is a key factor for biodiesel. Jatropha curcas L. has emerged as a favorite unconventional source of fuel. This paper aims to map the changes in Jatropha curcas L. oil, extracted from seeds subjected to natural aging (NA), accelerated aging (AA) and saturated salt accelerated aging (SSAA) are two methods employed to mimic natural aging. The results depicted that prolonged and intense aging decreased the oil yield and caused deterioration of the oil with a high free fatty acids content, saponification value, peroxide value, and low iodine value. Decrease in oleic acid content is the result of lipid peroxidation due to prolonged storage. However, Jatropha curcas L. seeds subjected to natural aging even up to one year could still serve as the best feedstock because of its resistance towards deteriorative aging effects.     

Biophysicochemical evaluation and micropropagation study of Jatropha curcas L. collections for biodiesel production

Jatropha curcas, a member of the Euphorbiaceae family, is an upcoming energy source, which promises to mitigate the energy crisis and environmental pollution. Jatropha curcas oil is looked up in terms of availability and cost and also has several applications and enormous economic benefits. The seed oils of five Jatropha curcas biotypes were screened and evaluated for their physiochemical parameters, viz. oil content (20–43%), biodiesel yield (48–66%), density (.866–.969 g/cm³), viscosity (50.12–93.79 mm³/s), iodine value (232.738–457.16 mg/g), free fatty acid (18.847–7.614 mg/g), saponification value (59.29–93.79 mg/g), flash point (125–220°C), fire point (155–260°C) and ash content (.19–.399%), which were estimated for selection of the elite Jatropha curcas biotype. The best shoot regeneration (60%) was observed in Murashige and Skoog (MS) medium supplemented with naphthalene acetic acid (0.5 ppm) and benzyl amino purine (2.0 ppm). Root induction (90%) was successfully obtained in plain MS. Acclimatisation and hardening was quite successful with survival rate of 70%.     

Biodiesel production process optimization and characterization to assess the suitability of the product for varied environmental conditions

In this study, both edible (coconut oil, palm oil, groundnut oil, and rice bran oil) and non-edible oils (pongamia, neem and cotton seed oil) were used to optimize the biodiesel production process variables like catalyst concentration, amount of methanol required for reaction, reaction time and reaction temperature. The fuel properties like specific gravity, moisture content, refractive index, acid value, iodine number, saponification value and peroxide value were estimated. Based on the cetane number and iodine value, the methyl esters obtained from palm and coconut oils were not suitable to use as biodiesel in cold weather conditions, but for hot climate condition biodiesel obtained from the remaining oil sources is suitable.     

Influence of extended storage on fuel properties of methyl esters prepared from canola,palm, soybean and sunflower oils

Fatty acid methyl esters prepared from canola, palm, soybean, and sunflower oils by homogenous base-catalyzed methanolysis were stored for 12 months at three constant temperatures (? 15, 22, and 40 °C) and properties such as oxidative stability, acid value, kinematic viscosity, low temperature operability, and iodine value were periodically measured. Oxidative stability was significantly reduced upon extended storage and acid value as well as kinematic viscosity were increased by only small increments, with these effects more pronounced at elevated temperatures. Iodine value and low temperature operability were essentially unaffected by extended storage. Based on these findings, it is not recommended that acid value or kinematic viscosity be used as indicators of storage stability of biodiesel, nor is it recommended that iodine value be used as a predictor of oxidative stability or indicator of oxidative degradation.     

Physico-chemical properties of plant oils and blends in diesel and kerosene oils

The density, viscosity, heating value, flash point and acid value of unprocessed plant oils of the six commonly cultivated crops and 2:1 and 1:2 volumetric blends of each plant oil separately with high-speed diesel oil(HSD) and kerosene oil(KO) were measured and compared with the properties of conventional diesel engine fuels (i.e. HSD and KO). Empirical equations relate viscosity and density to temperature and blending ratio for each plant oil. The density of the oils decreased linearly with an increase in temperature and with an increase in the proportion of HSD/KO in the blended fuels. The viscosity of the plant oils was much higher than that of HSD/KO but reduced drastically on heating or blending in HSD or KO. The gross heating value of the plant oils was found to be 85.80 to 88.85% of that of HSD. The acid values of the plant oils were found to be greater than that for HSD/KO, but some oils satisfied the Indian Standard Institution requirement on acid value for HSD fuel. The flash points of the oils were found to be much higher than for HSD/KO.     

Green-filamentous macroalgae Chaetomorpha cf. gracilis from Cuban wetlands as a feedstock to produce alternative fuel: A physicochemical characterization

The excessive blooming of green filamentous macroalgae is a global problem due to their unwanted presence in freshwater, lakes, nursery garden and stagnant waters. An attractive solution is to use macroalgae as a biofuel feedstock. In this work, the macroalgae studied was the Chaetomorpha cf. gracilis. The macroalgae oil extraction was accomplished using Soxhlet method obtaining a yield of 1.85%. The gas chromatography analysis showed higher unsaturated fatty acids (56.14%) compared to saturated fatty acids (35.18%), highlighting the content of oleic acid, 27.89%. The kinematic viscosity and density were 0.826 mm²/s and 699.6 kg/m³, respectively. The heating value, crystallization temperature and elemental composition showed higher values than other algae oils. Nevertheless, the nitrogen content was similar to L.digitata macroalgae. The analysis conducted on the net energy ratio for the oil extraction process showed that the Chaetomorpha macroalgae oil might represent an attractive alternative for liquid biofuel production.     

Fatty acids composition as a means to estimate the high heating value (HHV) of vegetable oils and biodiesel fuels

High heating value (HHV) is an important property which characterises the energy content of a fuel such as solid, liquid and gaseous fuels. The previous assertion is particularly important for vegetable oils and biodiesels fuels which are expected to replace fossil oils. Estimation of the HHV of vegetable oils and biodiesels by using their fatty acid composition is the aim of this paper. The comparison between the HHVs predicted by the method and those obtained experimentally gives an average bias error of −0.84% and an average absolute error of 1.71%. These values show the utility, the validity and the applicability of the method to vegetable oils and their derivatives.     

Effects of preheating of crude palm oil (CPO) on injection system, performance and emission of a diesel engine

Crude palm oil (CPO) is one of the vegetable oils that have potential for use as fuels for diesel engines. CPO is renewable, and is safe and easy to handle. However, at room temperature (30–32°C) CPO has a viscosity about 10 times higher than that of diesel. To lower CPO’s viscosity to the level of diesel’s viscosity, a heating temperature of at least 92 °C is needed. At this temperature, there is a concern that the close-fitting parts of the injection system might be affected. This study focused on finding out the effects of preheating of fuel on the injection system utilising a modified method of friction test, which involves injecting fuel outside the combustion chamber during motoring. Results show that preheating of CPO lowered CPO’s viscosity and provided smooth fuel flow, but did not affect the injection system, even heating up to 100 °C. Nevertheless, heating up to such a high temperature offered no benefits in terms of engine performance. However, heating is necessary for smooth flow and to avoid fuel filter clogging. Both can be achieved by heating CPO to 60 °C. Combustion analyses comparisons between CPO and diesel found that CPO produced a higher peak pressure of 6%, a shorter ignition delay of 2.6°, a lower maximum heat release rate and a longer combustion period. Over the entire load range, CPO combustion produced average CO and NO emissions that were 9.2 and 29.3% higher, respectively, compared with those from diesel combustion.     

Production of biodiesel from low priced,renewable and abundant date seed oil

The present work is definitely an approach towards attaining price competency of bio-diesel to petroleum diesel. The oils extracted from abundantly available waste of Zahidi, Basra and Khazravi date seeds were used to produce biodiesel using acid (HCl), base (KOH), immobilized enzyme (lipase), immobilized enzyme/acid (lipase/HCl) and immobilized enzyme/base (lipase/KOH) catalyzed processes. Mixed catalysis (immobilized enzyme + acid or immobilized enzyme + base) resulted in better yields in comparison to acid or base catalysis. The properties of biodiesel were evaluated by fuel standard tests and the results were compared with EN14214 and ASTM D6751 standards. Biodiesel produced from date seed oil was found to have a high cetane number (55–60.3), low iodine value (44–50) and good flash point (135–140 °C). Pour point of pure biodiesel produced from Khazravi and Zahidi was found to range from 2 to −2 °C. Biodiesel produced from Basra exhibited good pour point (−4.7 to −8.3 °C) in comparison to other varieties. The components present in biodiesel produced from various date varieties were determined by gas chromatographic-mass spectrometric analyses (GCMS). The fatty acid (%) detected in date seed biodiesel were oleic acid (33.4–47.4), lauric acid (19–28), palmitic acid (13.6–19.2), myristic acid (13.6–17.44) and linoleic acid (6.4–8.5). A special feature of date seed oil biodiesel was the presence of considerable amounts of low chain fatty acids.     

Review of biodiesel composition, properties, and specifications

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.     

Characterization of Jatropha curcas oils and their derived fatty acid ethyl esters obtained from two different plantations in Cuba

The scope of this work is to evaluate some properties of the oils and derived fatty acid ethyl esters (FAEE) from two different Jatropha Curcas species planted in Cuba. The properties that were determined include the acid value, peroxide value, p-anisidine value and fatty acid ethyl esters composition. In order to study the influence of the genus species and geographic conditions on the fuel properties, the oils from Jatropha Curcas planted in two regions of Cuba and their derived FAEE were analyzed and compared. The two plantations were in San José (SJ) and Guantanamo (Gt) representing respectively the western and eastern part of the island.The analyses indicated that the FAEE obtained from Guantanamo has a higher acid value and peroxide value compared with the FAEE from San José. The p-anisidine values did not show a clear trend and the results of gas chromatography-mass spectrometry indicated a similar FAEE composition. The results obtained by gas chromatography are in good agreements with previous reports.     

Stability of wood fast pyrolysis oil

This study evaluates the effects of storage conditions on physical and chemical properties of biomass fast pyrolysis oils exposed to elevated temperatures over extended periods of time. It was performed on oak pyrolysis oil generated in the NREL vortex reactor. Oil samples were stored at three temperatures: 37, 60 and 90°C in glass vessels. Properties of the oils were measured after hours of storage at 90°C, and after days or weeks at lower temperatures. Chemical changes in the oils were measured using GPC (molecular weight distribution) and FTIR spectroscopy. The oil remained a single phase throughout the studied conditions. Its pH was not affected by storage. The water content, viscosity and molecular weight of the oil increased with the time and temperature of storage. First-order reaction kinetics were successfully used to predict changes in molecular weight of the stored oil. FTIR provided evidence that etherification or esterification are mechanisms for condensation of the oil during storage.