BIODIESEL PRODUCTION FROM LUNARIA OIL (L. annua) G.S.DODOS, G.STAMATIOU and F.ZANNIKOS

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1 Proceedings of the 13 th International Conference on Environmental Science and Technology Athens, Greece, 5-7 September 2013 BIODIESEL PRODUCTION FROM LUNARIA OIL (L. annua) G.S.DODOS, G.STAMATIOU and F.ZANNIKOS Laboratory of Fuel Technology and Lubricants, School of Chemical Engineering, National Technical University of Athens, Heroon Polytechniou 9, Zografou, Greece EXTENDED ABSTRACT Biodiesel is a renewable substitute of diesel fuel - predominantly in the form of Fatty Acid Methyl Esters - that is being added nowadays as a mixing component at a maximum concentration of 7% v/v. According to several European Energy/Fuel Directives a 10% target has been set by 2020 concerning the energy from renewable sources in the transport, whereas a 6% reduction in the greenhouse gases of fuels used in road transport has to be achieved by the same year. Recently a new European Commission proposal has been made public designating that the share of energy from biofuels produced from food crops shall be no more than 5% of the final consumption of energy in transport. Moreover, the expected introduction of ILUC (Indirect Land-Use Change) factors, in order to account for the greenhouse gas emissions associated with the changes in land use, is also believed to impact the biofuels availability. In Europe a continuing shift from gasoline to diesel fuel is observed leading to increased demands of diesel and subsequently biodiesel fuel. Since the 1st generation biofuels (FAME, FAEE) are still the prominent widely available diesel substitutes, the utilization of alternative nonfood crops as feedstock is advised so as to able to harmonize-to a certain extend - with the new regulatory frame. Based on the above, the aim this study was to examine the utilization of Lunaria Oil (L. annua) as a starting material for the production of biodiesel and particularly Fatty Acid Methyl Esters (FAME). At first the general properties and the profile of the neat oil was investigated. The analysis showed that the oil is abundant in mono-unsaturated fatty acids such as oleic, erucic, nervonic. The unique characteristic compared to other vegetable oils lies in the fact that erucic and nervonic fatty acids account for more than 60% of the total fatty acid composition. In order, now, to convert the lunaria oil to biodiesel, it was transesterified to the corresponding alkyl esters in the presence of methanol. Sodium methoxide was used as catalyst. After reaction was completed, the alkyl esters phase was isolated, purified and the quality parameters were assessed in accordance to the European Standard EN Due to the contained high amount of long chain fatty acids the kinematic viscosity of the esters cannot fulfill the European Specification but this could be counterbalanced though blending. Nevertheless, the high monounsaturated content is significantly beneficial to other properties such as oxidation stability and as a whole lunaria oil appears to be a promising feedstock for the production of biodiesel. Keywords: Lunaria Oil, biodiesel, FAME, B7 Blend 1. INTRODUCTION Biodiesel is the most widely used first generation biofuel. It is a renewable alternative diesel fuel consisting of fatty acid methyl esters (FAME) of vegetable or animal origin. Nowadays, the maximum FAME concentration in European Union is 7% v/v and the

2 mixing ratio might increase more in the forthcoming years so as to meet the new directives for further reduction in the greenhouse gases emissions. According to several European Energy/Fuel Directives (2009/28/EC και 2009/30/EC) a 10% target has been set by 2020 concerning the energy from renewable sources in the transport, whereas a 6% reduction in the greenhouse gases of fuels used in road transport has to be achieved by the same year. Recently a new European Commission proposal [1] has been made public designating that the share of energy from biofuels produced from food crops shall be no more than 5% of the final consumption of energy in transport. Moreover, the expected introduction of ILUC (Indirect Land-Use Change) factors, in order to account for the greenhouse gas emissions associated with the changes in land use, is also believed to impact the biofuels availability. In Europe a continuing shift from gasoline to diesel fuel is observed leading to increased demands of diesel and subsequently biodiesel fuel [2]. Rapeseed, soybean and sunflower oil are the main source materials for biodiesel production within Europe; however they still constitute edible crops in some cases [3]. Since the 1st generation biofuels (FAME) are still the prominent widely available diesel substitutes, the utilization of alternative non-food crops as feedstock is advised so as to able to harmonize - to a certain extend - with the new regulatory frame. Lunaria (Lunaria annua or Honesty) is generally a self-sown plant which is very common in Greece and generally native in south eastern Europe and south west Asia. It is usually grown as a biennial, although some annual species also exist. It can be found commonly along roads and in semi-shady places. It is also cultivated as an ornamental flower. Lunaria is a cruciferous plant growing to a maximum of cm tall with large, coarsely toothed oval leaves. During spring and summer it produces purple (or white) flowers, followed after a while by circular pods containing the seeds. The latter contains about % oil consisting mainly of long chain fatty acids such as erucic and nervonic acids. Besides, it is not considered to be an edible oil and for this reason it is being studied as a new crop either for industrial applications or medicinal purposes. The biennial character of Lunaria is usually regardes as a main constraint for an economical viable cultivation. Efforts are currently being made in order to to overcome the Limited knowledge of crop culture & potential and to optimize the production conditions especially of the annual species [4,5]. Based on the above, the aim this study was to examine the utilization of Lunaria oil as a starting material for the production of biodiesel and particularly Fatty Acid Methyl Esters (FAME). In order to convert it to biodiesel, the fatty oil was transesterified to the corresponding methyl esters in the presence of methanol. The quality parameters of lunaria oil methyl esters - either neat or blended with conventional diesel - were assessed in accordance to the European Standards EN and EN590 respectively. 2. EXPERIMENTAL 2.1. Materials and Reagents Lunaria oil was obtained from a local manufacturer and was used without further processing. The properties of the base oil are listed in Table 1. Moreover, methanol, 99.99% purity was obtained from Fisher Scientific and Sodium Methoxide, pure, anhydrous powder, was taken from Acros Organics.

3 Table 1. Physicochemical properties of Lunaria Oil Property Units Lunaria Oil Method Density at 15 C kg/m EN ISO KV at 40 C mm 2 /s EN ISO 3104 Water Content mg/kg 200 EN ISO Acid Value mg KOH/g 2.70 EN Saponification Value o C 167 AOCS Cd Methodology Production of Lunaria oil biodiesel Lunaria oil Methyl Esters (LUNME) were prepared by methanolysis of lunaria oil using sodium methoxide (CH 3ONa) as catalyst at a concentration of 1.0 wt%. The reaction was carried out at 65 o C for 2h employing a 6:1 methanol/oil molar ratio. After the completion of transesterification reaction, the upper methyl esters phase was separated from the glycerol phase and a dry purification procedure was followed. The excess of methanol was removed by rotary evaporator. The purified methyl esters were dried over anhydrous sodium sulphate (Na 2SO 4) and after vacuum filtration the final LUNME were obtained Quality Assessment of LUNME The produced methyl esters were examined regarding their use as automotive fuel for diesel engines. The analysis was performed according to the specified requirements and test methods included in the European Standard EN The fatty acid composition of LUNME was determined by gas chromatography using a DANI Master GC apparatus in accordance with EN Table 2. Properties of ULSD Property ULSD EN590 limits Method k.viscosity, (mm 2 /s, 40 C) EN 3104 Density, (kg/m 3, 15 C) EN 3675 Sulfur content (mg/kg) 9 10 max. EN Water content (mg/kg) max. EN Distillation ( C) IBP %, % % % % % % 353 FBP 367 Recovery (%) 97.8 EN 3405 Cetane index min. EN 4264 Copper strip corrosion, (3h at 50 C, rating) 1A Class 1 EN 2160 Polycyclic aromatic hydrocarbons (% m/m) max. EN Lubricity, WS 1.4 (μm) max CEC F-06-A-96

4 Preparation of LUNME/diesel Blend LUNME was blended with an Ultra Low Sulphur Diesel (ULSD) fuel at a concentration of 7% v/v (B7). In the European Union this is currently the maximum allowable FAME content in automotive diesel as designated by the Standard EN590:2009. The ULSD fuel was a hydrotreated atmospheric gasoil, it was supplied from a Greek refinery and it was additive free. The fuel properties are presented in Table 2, along with the standard methods that were used for their determination. The prepared blend was examined regarding its physicochemical properties such as density, kinematic viscosity, oxidation stability and acid value. 3. RESULTS AND DISCUSSION 3.1. Fatty Acid Profile of Lunaria oil The fatty acid composition of Lunaria oil - measured on methylesters basis - is listed in Table 3 and it could be characterized pretty idiomorphic compared to the profile of other commonly used lipids [4,6,7]. The analysis showed that lunaria oil is abundant in monounsaturated fatty acids (~ 90% wt.), consisting mainly of nervonic (C24:1), erucic (C22:1) and oleic (C18:1) acid at a concentration of 43.25%wt, 23.01%wt and 23%wt respectively. The other main fatty acids are linoleic (6.31 wt%) and palmitic (1.17 wt%). Very low levels of linolenic acid have been detected (0.95 wt%). The unusual composition of lunaria oil along with its non-edible nature can make its utilization as industrial crop very attractive. Table 3. Fatty acid composition of lunaria oil methyl ester Fatty Acids Chemical structure weight% Myristic C14:0 CH3(CH2)12COOH 0.24 Palmitic C16:0 CH3(CH2)14COOH 1.17 Palmitoleic C16:1 CH3(CH2)5CH=CH(CH2)7COOH 0.28 Stearic C18:0 CH3(CH2)16COOH 0.2 Oleic C18:1 CH3(CH2)7CH=CH(CH2)7COOH Linoleic C18:2 CH3(CH2)3(CH2CH=CH)2(CH2)7COOH 6.31 Linolenic C18:3 CH3(CH2CH=CH)3(CH2)7COOH 0.95 Gadoleic C20:1 CH3(CH2)8CH=CH(CH2)8COOH 0.5 Erucic C22:1 CH3(CH2)7CH=CH(CH2)11COOH Nervonic C24:1 CH3(CH2)7CH=CH(CH2)13COOH LUNME Properties Regarding the quality parameters it is obvious from the results presented in Table 4 that Lunaria oil biodiesel satisfy the overwhelming majority of the measured applicable requirements as automotive diesel fuel outlined in the European Standard EN During transesterification process the undesirable saponification and neutralization side reactions were significantly suppressed and as a result the conversion was practically complete. The ester content was determined to be 96.6% which is above the specified lower limiting value. The completion of the reaction is also depicted in the measured values of the density (877 kg/m 3 ). Moreover, the water content as well as the acid value of the prepared LUNME are within the acceptable levels. A high water concentration may cause either engine corrosion or a reversion of fatty acid methyl esters to fatty acids, whereas increased acid value imply high content of Free Fatty Acids. Despite the high degree of unsaturation the iodine value was found to be around 80, well below the EN

5 specification limits. The GC glycerides analysis of the methylesters showed that the remaining levels of,di- and tri-glycerides are far below the maximum permitted values. In general, high contents of glycerides are undesirable as they may cause formation of deposits on injections and valves [7]. Free glycerol content was also found to be relatively low indicating effectual glycerol separation and methylester purification. Table 4. Properties of lunaria oil methyl ester (LUNME) Property Units LUNME EN14214 limits Method Ester Content % m/m 96.6 min 96.5 ΕΝ Density at 15 C kg/m EN ISO K.Viscosity at 40 C mm 2 /s EN ISO 3104 Water Content mg/kg 220 max 500 EN ISO CFPP C -12 (climate related) EN 116 Linolenic acid methyl ester % m/m 0.95 max 12 ΕΝ Oxidation Stability Rancimat hours min 8 ΕΝ PetroOxy min EN Acid Value mg KOH/g 0.42 max 0.50 EN Iodine Value g Ι2/100g ~80 max 120 EN Monoglyceride content % m/m (n/a) max 0.80 EN Diglyceride content % m/m 0.06 max 0.20 EN Triglyceride content % m/m 0.04 max 0.20 EN Free glycerol % m/m 0.01 max 0.02 EN Total glycerol % m/m (n/a) max 0.25 EN Cold flow properties and oxidative behavior appears to be the top quality parameters of lunaria derived biodiesel. LUNME possess excellent low temperature characteristics. The relative measurements resulted in a CFPP equal to -12 C, which is far below the average value demonstrated by the majority of FAMEs [7,8]. Furthermore, LUNME exhibits extraordinarily high oxidation stability in both Rancimat and RSSOT (Rapid Small Scale Oxidation Test) methods. Especially in the Rancimat apparatus the lower limiting value of 8h is very easily surpassed. The oxidation rate is very low, resulting in an unprecedented induction period of 30.5h, which is far beyond of what even palm oil methyl ester can achieve [9]. This superior behavior is also verified in the RSSOT, with an induction period of 165min. In comparison, the commonly used FAMEs give rise to an induction period ranging between min under the RSSOT conditions [9]. The very high levels of mono-unsaturated fatty acids - and the subsequent low levels of poly-unsaturated fatty acids - might be one reason for this unforeseen oxidation stability. Generally higher polyunsaturation of the FAMEs molecule results in poorer oxidation stability due to the vulnerability of the bis-allylic groups to oxidative deterioration [10]. On the other hand one of the main drawbacks of LUNME lies in the fact that it is incapable of achieving a kinematic viscosity value within specification. Viscosity is an important parameter regarding fuel atomization as well as fuel distribution [6,8]. For biodiesel to be used in diesel engines, kinematic viscosity must be between 3.5 and 5.0

6 mm 2 /s. LUNME possess a viscosity of 6.8 mm 2 /s, pretty higher that the upper limiting value. This property could be attributed to the considerable amounts of high-molecular weight fatty acids (erucic and nervonic) contained [11]. Although this seems to deprive lunaria oil of being used as a sole source material for biodiesel production, taking into consideration the other advantageous characteristics, still it can be considered as a blending component in a given feedstock B7 LUNME Properties The fuel properties of B7 blend of LUNME in ULSD along with a comparison to the EN 590 standards are presented in Table 5. Fuel properties determined in the current study included density, kinematic viscosity, oxidation stability and acid value. It is obvious that the density and kinematic viscosity values are within the specified range. Especially, it appears that - despite the high viscosity of pure LUNME -, at a concentration of 7%v/v the k. viscosity of ULSD was not dramatically affected and therefore was kept well below the 4.5 mm 2 /s limit. Lubricity measurement in the HFRR apparatus show that the good lubricating effectiveness of neat FAME was imparted to the B7 blend. The wear scar value of the base fuel was substantially decreased from 496 to 228μm. The superior tribological behaviour of FAME - and generally of oxygen containing compounds - over ULSD has been repeatedly reported in the literature and is attributed to the functionality of the - COOCH 3 moiety [12]. EN 590 do not contain acid value specification, however the determined value of 0.21 mg KOH/g is considered pretty satisfactory. Finally, the exceptional oxidation stability of LUNME could also stand out in the B7 blend. In the Rancimat method the EN 590 minimum value of 20h oxidation stability concerning biodiesel blends containing up to 7% v/v FAME is readily satisfied, while the result in the RSSOT method indicates a very stable fuel that can be compared with or even sometimes go beyond the oxidative characteristics of conventional petroleum diesel [9]. Table 5. Properties of B7 LUNME - ULSD Blend Property Units B7 LUNME EN590 limits Method Density at 15 C kg/m EN ISO K.Viscosity at 40 C mm 2 /s EN ISO 3104 Oxidation Stability Rancimat hours min 20 ΕΝ PetroOxy min EN Acid Value mg KOH/g EN Lubricity μm CEC F-06-A CONCLUSIONS In this study Lunaria oil (Lunaria annua) was utilized as an alternative feedstock for the production of biodiesel. The fatty oil was converted to the corresponding fatty acid methyl esters via alkaline transesterification. Lunaria oil methylesters were evaluated according to european standards EN14214 and EN590 as automotive fuel for diesel engines either neat or blended with conventional ultra low sulphur diesel at a concentration of 7% v/v. The following conclusions could be made:

7 The analysis of lunaria oil showed that it is abundant in monounsaturated fatty acids, in particular nervonic, erucic and oleic acid. This unconventional composition along with the non-edible character of the oil can make its utilization as industrial crop very attractive. A high yield conversion was achieved during transesterification reaction of lunaria oil to lunaria methyl esters. The subsequent quality assessment revealed that LUNME can meet the majority of EN14214 requirements. The remarkable oxidation stability and the excellent cold flow properties are the key advantages of LUNME, whereas the main weakness lies in the high kinematic viscosity value. However, this could be counterbalanced though blending. Further work is being currently conducted by examining lunaria oil as a mixing component in biodiesel feedstock. REFERENCES 1. COM(2012) 595 final, Proposal for a directive of the European Parliament and of the Council amending directive 98/70/EC relating to the quality of petrol and diesel fuels and amending Directive 2009/28/EC on the promotion of the use of energy from renewable sources, 2012/0288 (COD). Brussels, Maniatis K. (2012), Advanced Biofuels: The way forward, International Conference on Biofuels for Sustainable Development of Southern Europe (Bio4SuD), November Thessaloniki, Greece 3. Escobar J.C. Lora E.S., Venturini O.J., Yanez E.E., Castillo E.F., Almazan O., (2009) Biofuels: Environment, technology and food security, Renewable and Sustainable Energy Reviews 13, Gunstone F.D., Harwood J.L., Dijkstra A.J.(2007), The lipid handbook - 3rd ed., Taylor & Francis Group, LLC, ISBN-13: Mastebroek H.D., Marvin H.J.P., (2000) Breeding prospects of Lunaria annua L., Industrial Crops and Products Singh S.P., Singh D. (2010), Biodiesel production through the use of different sources and characterization of oils and their esters as the substitute of diesel: A review, Renewable and Sustainable Energy Reviews 14, Demirbas A.,(2008) Biodiesel : a realistic fuel alternative for diesel engines, Springer-Verlag London, ISBN Hoekman S.K., Broch A., Robbins C., Ceniceros E., Natarajan M. (2012), Review of biodiesel composition, properties, and specifications, Renewable and Sustainable Energy Reviews 16, Dodos G.S. (2013), Effect of Renewable Biobased Substitutes on Lubricating Properties, Oxidation Stability and Microbial Growth of Petroleum Products, PhD Thesis, National Technical University of Athens. 10. Zuleta E.C., Baena L., Rios L.A., Calderón J.A. (2012), The oxidative stability of biodiesel and its impact on the deterioration of metallic and polymeric materials: a review, J. Braz. Chem. Soc. 23 (12) Knothe G., Steidley K R.(2011), Kinematic viscosity of fatty acid methyl esters: Prediction, calculated viscosity contribution of esters with unavailable data, and carbon oxygen equivalents, Fuel Agarwal S., Chhibber V.K., Bhatnagar A.K.(2013), Tribological behavior of diesel fuels and the effect of anti-wear additives, Fuel