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bovine tallow methyl biodiesel blends
Industrial Crops & Products 140 (2019) 111667
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Evaluation of the oxidative stability and cold filter plugging point of soybean methyl biodiesel/bovine tallow methyl biodiesel blends
T
Osmar Nunes de Freitasa, Rafael Cardoso Rialb, , Leandro Fontoura Cavalheiroa, Joyce Mara dos Santos Barbosaa, Carlos Eduardo Domingues Nazárioa, Luíz Henrique Vianaa ⁎
a b
Instituto de Química, Universidade Federal de Mato Grosso do Sul, 79070-900 Campo Grande MS, Brazil Instituto Federal de Mato Grosso do Sul, 79750-000, Nova Andradina MS, Brazil
ARTICLE INFO
ABSTRACT
Keywords: Soybean methyl biodiesel Bovine tallow methyl biodiesel Oxidative stability Cold filter plugging point Blends
The objective of the present work was to study the oxidative stability (OS) estimated from the induction period (IP) and the cold filter plugging point (CFPP) of blends made with different proportions of soybean methyl biodiesel (BOS) and bovine tallow methyl biodiesel (BSB). BOS is poorly resistant to oxidation because its composition is predominantly unsaturated esters, but it has a satisfactory cold filter plugging point. The BSB is composed of saturated esters and of the lower carbon chain and thus has good oxidation stability values, but has poor CFPP values. Thus, BOS / BSB mixtures in different proportions were made to evaluate the ideal amount of the mixture in which it was possible to obtain IP and CFPP properties in satisfactory values by the legislation. The mixtures started at 10% BSB and 90% BOS and was increased 5% up to the 50% percentage of each biodiesel in each blend. Samples with 45% and 50% BSB had oxidative stability above the minimum required by law, and all blends had the CFPP value within the legal values.
1. Introduction Biodiesel is a biodegradable fuel made from renewable raw materials, consisting of alkyl esters, which uses vegetable oils or animal fats as the starting material for the transesterification and / or esterification reaction, and can be used on diesel engines with compression ignition, mixed to mineral oil in various proportions or pure (Mendes and Costa, 2010). Biodiesel has advantages over diesel oil, as it is less polluting, has higher cetane number, flash point and lubricity (Knothe and Steidley, 2005; Knothe, 2010). In Brazil, the two main sources used in the country for the production of biodiesel are soybean oil and bovine tallow, which together account for approximately 91% of all biodiesel produced in the country (Knothe et al., 2006). The National Agency of Petroleum, Natural Gas and Biofuels - ANP - regulates the fuel and biofuels sector in Brazil and recommends - through ANP Resolution No. 45/2014 - that all biodiesel sold in the country meets some quality requirements. Soybean biodiesel meets the specifications of quality, but has the disadvantage of having a low oxidative stability (OS) due to its composition being approximately 75% from unsaturated fatty acids (Meneghetti et al., 2007). On the other hand, bovine tallow biodiesel has few unsaturated fatty acids (Silva et al., 2015). Therefore, bovine tallow biodiesel has a higher
⁎
oxidative stability and lower cold filter plugging point (CFPP) (Wyatt et al., 2005). Some CFPP and OS studies between BOS/BSB mixtures are available in the literature. Teixeira, L. S. G., et al., 2010 evaluated some physicochemical properties, including CFPP, of mixtures of soybean methyl biodiesel/beef tallow methyl biodiesel, ranging from 10 to 90% (v/v), and the values of CFPP increased as the proportion of beef tallow increased in the mixture (Teixeira et al., 2010). Pereira, G. G., et al., 2017 studied the oxidative stability in soybean/beef tallow biodiesel blends in the proportion 70/30 and 50/50 (w/w) during the storage of 350 days and these mixtures showed higher resistance oxidation when compared to oxidative stability of soybean biodiesel (Pereira et al., 2017). On the other hand, these two studies did not simultaneously evaluate these two physicochemical properties in BOS/BSB mixtures, which vary depending on the process of obtaining these biofuels. Therefore, it is important to evaluate these two physicochemical properties simultaneously in BOS / BSB mixtures obtained under the same reaction conditions. In the presente work evaluated the oxidative stability by measuring the induction period (PI) and CFPP of different mixtures with different amounts of soybean methyl biodiesel and tallow bovine biodiesel in order to investigate the possibility of producing a mixture that could
Corresponding author. E-mail address: [email protected] (R. Cardoso Rial).
https://doi.org/10.1016/j.indcrop.2019.111667 Received 23 June 2019; Received in revised form 4 August 2019; Accepted 14 August 2019 0926-6690/ © 2019 Elsevier B.V. All rights reserved.
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increase IP value in relation to soybean methyl biodiesel and the CFPP value of beef tallow methyl biodiesel was decreased to meet the quality requirements available in current regulations that are necessary to ensure a quality biodiesel.
Table 1 Chromatographic Parameters GC - FID to analyze the chemical composition of BSB and BOS. Injector and detector parameters Injection volume Injector temperature (°C) Detector Injection mode Split Reason Detector temperature (°C) Oven parameters Heating rate (°C/min) Isotherm (min.) Total Running Time (min.) Temperature (°C) Drag gas Flow
2. Methodology 2.1. Obtaining bovine tallow metyl biodiesel The bovine tallow was purchased at a supermarket in the city of Campo Grande - MS - Brazil, and after cleaning, it was placed in a container with heating for 1 h and 120 °C to obtain fat. After melting, the filtration and separation of the water were made. In order to obtain the biodiesel, the bovine tallow was heated at 85 °C in the molar ratio tallow bovine: methyl alcohol 1:6 mol/mol, using 0.5% sodium hydroxide (NaOH) as catalyst, with a reaction time of 1 h under stirring at 400 rpm. The reaction was monitored by thin layer chromatography (CCD) and after the end of the reaction time, the biodiesel was separated from the glycerine, washed and then dried using anhydrous magnesium sulfate, thus obtaining the bovine tallow methyl biodiesel (BSB).
4 10 52 80 Helium 1 mL/min
2.5. Physico-chemical Properties of bovine tallow, soybean oil, BSB and BOS For the physical chemical characterization of the raw materials, the following parameters were measured: Acidity Index (EN14104), Water content (ASTM D 6304), Iodine value (EN 14111) and Specific Mass at 20 °C (ASTM D 4052).
2.2. Obtaining soybean methyl biodiesel To obtain the soybean methyl biodiesel (BOS), the soybean oil was maintained at a temperature in the range of 35 °C–40 °C, sodium hydroxide (NaOH) was used in a proportion of 1% by oil mass. The molar ratio of soybean oil: methanol was 1: 6 mol mol and the reaction time was 40 min. The reaction was monitored by CCD and after the reaction time was over, the BOS was washed to facilitate the separation of the glycerin, rotavaporated and then dried using anhydrous magnesium sulfate.
2.6. BOS: BSB blends As the production in Brazil of BOS is higher than BSB, mixtures with more than 50% BSB would make it impossible to meet this need. Thus, the BOS and BSB samples were mixed in varying amounts to form the mixtures, starting initially with 90% BOS and 10% BSB, and increasing 5% BSB with each new blend to reach 50% of each biodiesel. The volume of the mixtures was determined by the amount to be used in the analyzes. The mixtures obtained are detailed in Table 2. After the mixtures, aliquots of the formed blends were submitted to OS and CFPP analysis and the results were evaluated comparing with the results of the pure biodiesel and the values indicated by the legislation.
2.3. Characterization of bovine tallow, soybean oil, BSB and BOS Aliquots of bovine tallow, soybean oil, BSB and BOS were routed to H NMR spectra. NMR spectra were performed on a Bruker spectrometer of 7.05 T, model DPX300 (300.13 MHz for hydrogen frequency), using deuterated chloroform (CDCl3) as solvent.
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2.7. Evaluation of oxidative stability of biodiesel and blends Samples of BOS, BSB and blends were analyzed according to the Rancimat® method, according to European Standard EN 14112, using METROHM equipment (Model Rancimat 873), under heating at 110 °C and constant flow of air 10 Lh−1. The temperature correction factor (ΔT) was set at 0.9 °C as recommended by EN14112. The amount of sample used was 3.0 g.
2.4. Chemical composition of bovine tallow, soybean oil, BSB and BOS To determine and quantify the chemical composition of methyl esters of fatty acids that compose the BSB and BOS was used gas chromatography coupled to flame ionization detector (GC-FID) with internal standard for calibration. The procedure adopted is European standard EN 14103. The amount of 250 mg of each sample was mixed with 5 mL of 10 mg / mL methyl heptadecanoate solution (internal standard) and injected into the chromatograph. A Varian CP-3800 chromatograph with automatic injector and flame ionization detector (FID) was used to perform the procedure. The column used was a BPX 70 (SGE) measuring 30 m in length, 0.25 mm internal diameter and 0.25 μm film. Chromatographic parameters are shown in Table 1. A previous injection with chromatographic standards was performed to identify the peaks C14, C17 and C24:1 to define the quantification interval and to identify the retention time of the internal standard (C17). The ester content was determined by Equation (1): TE = {[(_A) - API / API] x [CPI x VPI / m]} x 100
1 μL 200 FID Split 1:100 250
2.8. Cold filter clogging point of biodiesel and blends To determine this property, the procedure described in ASTM Table 2 Optimization of biodiesel mixtures of soybean biodiesel and bovine tallow biodiesel for blends composition.
(1)
TE is the ester content; _A is the sum of the areas of all peaks; API is the area of the internal standard; CPI is the concentration of the internal standard; VPI is the volume of internal standard solution; m is the mass of the sample. 2
Sample
% BOS
Volume
% BSB
Volume
V. Total
M1 M2 M3 M4 M5 M6 M7 M8 M9
90% 85% 80% 75% 70% 65% 60% 55% 50%
45.0 mL 42.5 mL 40.0 mL 37.5 mL 35.0 mL 32.5 mL 30.0 mL 27.5 mL 25.0 mL
10% 15% 20% 25% 30% 35% 40% 45% 50%
5.0 mL 7.5 mL 10.0 mL 12.5 mL 15.0 mL 17.5 mL 20.0 mL 22.5 mL 25.0 mL
50.0 mL 50.0 mL 50.0 mL 50.0 mL 50.0 mL 50.0 mL 50.0 mL 50.0 mL 50.0 mL
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As the specific mass of the oil is greater than that of the tallow bovine, we can predict that the soybean oil has an amount of esters with a carbonic chain greater than the bovine tallow.
Table 3 Physical-chemical properties of soybean oil and bovine tallow. Property
Unity
Soybean oil
Bovine tallow
Acidity level % Acidity Water content Iodine value Especific mass
mg KOH/g % % g de I2/ 100 g g. cm−3
0.1510 0.07 0.09 115.35 0.919
0.0803 0.04 0.10 27.92 0.901
3.2. Production of soybean methyl biodiesel and bovine tallow methyl biodiesel Gelbard, G., et al., 1995 was one of the pioneers in using 1H nuclear magnetic resonance spectroscopy to analyze the yields of the transesterification reaction (Gelbard et al., 1995). Some authors state that 1H NMR is faster and simpler when compared to gas chromatography and liquid chromatography (Costa Neto et al., 2004). Despite this, other characterization techniques are available and are used to verify the transesterification reaction (Monteiro et al., 2008). By obtaining and analyzing the 1H NMR spectra it is possible to prove the formation of the biodieses and verify their purity. In the 1H NMR spectrum of BOS (Fig. 2) the following signals were observed: a singlet at δ =3.6 ppm which can be attributed to the methyl hydrogens of the ester group, as they typically appear in the region between δ = 3.5–3.7 ppm; a triplet at δ =2.24 ppm attributed to α-carbonyl methylene hydrogens; and a mutiplet in the region of δ = 2.0 to δ =1.0 ppm referring to the methylene groups of the esters carbon chain. The signal at δ =5.3 ppm refers to the olefinic protons and their low intensity is related to the low amount of unsaturated esters present. Compared with the 1H NMR spectrum of the soybean oil (Fig. 1) the total disappearance of the chemical displacement relative to the glycerides at δ = 4.1–4.3 ppm can be observed. The absence of these signals in the BOS spectrum confirms that the total consumption of the oil used as raw material occurred. In the bovine tallow spectrum (Fig. 3), the olefinic protons, in δ =5.31 ppm, appear between δ = 5.24 and 5.34 ppm; the methylene protons of glycerol (triglycerides) appear in the range of δ = 4.07–4.31 ppm represented by dublo-dubletes; the methyl protons are observed as triplet at δ =0.85 ppm; the alpha-carbonyl protons are observed as triplet at δ =2.28 ppm. In the 1H NMR spectrum of BSB (Fig. 4) the following signals were observed: a singlet at δ =3.63 ppm which can be attributed to the methyl hydrogens of the ester group, as these appear in the region between δ = 3, 5 - 3.7 ppm; a triplet at δ =2.27 ppm attributed to α-carbonyl methylene hydrogens; and a mutiplet in the region of δ = 2.0 to δ =1.0 ppm referring to the methylene groups of the esters carbon chain. The signal at δ =5.31 ppm refers to the olefinic protons and their low intensity is related to the low amount of unsaturated esters present, and we also observed the methyl protons
D6371 was used. 45 mL of each sample is precooled under standard conditions and at 1 °C intervals is suctioned by a pipette attached to a controlled vacuum system having a 45 μm metal mesh. The procedure is carried out until, due to the solidification of the sample, it can not flow into the vessel within 60 s. For the determination of this parameter the equipment used was the Automated CFPP Tester model AFP-101 of the mark TANAKA Scientific Limited. 3. Results and discussions 3.1. Physical - chemical properties and chemical composition of soybean oil and bovine tallow Soybean oil and bovine tallow had their properties evaluated for the selection of the most appropriate method for obtaining biodiesel. The results obtained are shown in Table 3. For soybean oil the acid value was 0.1510 mg KOH/g and the acid percentage was 0.07%. The values measured in bovine tallow were 0.0803 mg KOH/g for the acid number and the acid percentage was 0.04%. As the values of soybean oil and acidity of tallow were less than 0.5%, it was possible to choose alkaline transesterification in one step to obtain biodiesel, considering that the conversion of oils and fats presents a higher esters formation, when raw materials have a lower acidity index (Freedman et al., 1984). The water content in the oil and bovine tallow was also evaluated because the presence of moisture in the raw material decreases the biodiesel yield because it favors the saponification (Liu, 1994; Basu and Norris, 1996). The values observed were for soybean oil 0.090% and bovine tallow, 0.100%. The iodine value is a measure of the unsaturations present in the raw material and indicates its rate of degradation (Freire et al., 2012) and measured value for soybean oil was 115.35 g of I2/100 g of sample, while the bovine tallow had 27.92 g of I2/100 g of sample. The specific mass of the soybean oil was 0.919 g.cm−3 and 0.901 g.cm−3 for bovine tallow.
Fig. 1. 1H-NMR spectrum (300 MHz, CDCl3) of Soybean Oil. 3
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Fig. 2. 1H–NMR spectrum (300 MHz, CDCl3) of soybean methyl biodiesel (BOS).
as triplet at δ =0.85 ppm. Comparing the 1H NMR spectra of bovine tallow with the BSB spectrum, the total disappearance of the chemical displacement for the glycerides in δ = 4.1–4.3 ppm can be observed.
2009 studied the influence of the composition of fatty acids on the physical and chemical properties of biodiesel with high amounts of unsaturated esters presented the lowest oxidative stability and the biodieses with higher amounts of saturated esters had the point of CFPP the worst results (Ramos et al., 2009). Yuan, M. H., et al., 2017 carried out a study to find a statistically combination based on the composition of fatty acid methyl esters to predict CFPP (Yuan et al., 2017). To verify the quality of BOS and BSB the following physico-chemical properties were evaluated: Acid index, water content, iodine value, specific mass at 20 °C, CFPP and IP. It was also evaluated its apparent appearance that should be clear and free of impurities (LII). All results obtained are in Table 5 The physico-chemical properties of BOS and BSB showed that the biodiesel obtained met most of the quality requirements, except for the ester content for BSB which was 94.7% while the minimum required value was 96.5%. This shows the difficulty in the transesterification procedure, where several adjustments were necessary in the procedure, until we reached the best factors with the use of 0.5% catalyst and
3.3. Chemical composition of BOS and BSB and physical chemical parameters To quantify the fatty acid methyl esters (FAME) formed after the BOS and BSB transesterification reactions, gas chromatography coupled to the flame ionization detector (GC - FID) was used and the percentages are presented in Table 4. The total unsaturated esters of BOS was 84.0% and that of saturated esters was 15.98%. The BSB chemical composition showed a total of unsaturated esters of 41.33% and saturated esters of 58.58%. The higher amount of saturated esters than unsaturated is concerned with the inference about this biodiesel having difficulty meeting the parameters of CFPP, and also about its high oxidative stability since the saturated esters, are more resistant to oxidation. Ramos, M. J., et al.,
Fig. 3. 1H-NMR spectrum (300 MHz, CDCl3) of bovine tallow. 4
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Fig. 4. 1H-NMR spectrum (300 MHz, CDCl3) of bovine tallow biodiesel (BSB).
Jagadale and Jugulkar, 2012; Cunha et al., 2013a; Adewale et al., 2015; Kirubakaran and Arul Mozhi Selvan, 2018; Anguebes-Franseschi et al., 2019).
Table 4 Chemical composition of soybean methyl biodiesel and bovine tallow methyl biodiesel. FAME
BOS Concentration (%)
BSB Concentration (%)
(C14:0) (C15:0) (C16:0) (C16:1) (C17:0) (C18:0) (C18:1) (C18:2) (C18:3) (C20:0) (C22:0) Saturated FAME Monounsaturated FAME Polyunsaturated FAME Unsaturated FAME Total FAME
0.12 – 10.91 – – 3.15 26.65 51.76 5.59 0.80 1.00 15.98 26.65 57.35 84.00 99.98
5.13 1.20 25.04 3.82 3.08 22.76 34.51 2.60 – 1.37 – 58.58 38.33 2.60 40.93 99.51
3.4. Evaluation of the CFPP and OS of BOS: BSB blends The BOS presented the induction time of 4.33 hs confirming what the literature says about the difficulty of this biodiesel in meeting the parameters of the legislation that is of at least 8,00 h. This low stability of soybean methyl biodiesel is attributed to the fact that most of its esters (62%) are unsaturated. The BSB presented an IP of 9.79 h, which is above the minimum value required by the legislation, which is 8.0 h. This high stability of the BSB is attributed to the fact that most of its constituent esters are saturated. Biodiesel partially solidifies or loses its fluidity at low temperatures, suspending the fuel flow, clogging the filtration system, making it difficult to start the engine (Lôbo et al., 2009). Thus, CFPP is the measure of the lowest temperature at which a liquid can flow without causing problems. In cold climate regions, this is an important parameter to be determined because this procedure simulates the temperature at which the fuel can freeze in the engines. The CFPP values presented for the BOS were-4.0 °C and the BSB, 15 °C. Fig. 5 shows the IP and CFPP values for each of the mixtures and also for the two pure biodieses The increase in OS of the blend was evident as the proportion of BSB was increased. The result of the IP of sample M2, which contained 85% of BOS and 15% of BSB, was 4.43 h, just slightly above the value of pure BOS. But on average the BSB ratio was increased, the OS was increasing and at 40% BSB, the induction time was already close to the accepted
reaction temperature of 85 °C. In addition, the low oxidative stability of soybean-methyl biodiesel was evidenced, which did not reach the minimum IP parameter of 8.0 h established by the ANP, whose value was 4.33 h. It was also confirmed the ease of the biodiesel of bovine tallow to crystallize, because it was obtained the temperature of 15 °C. Other studies demonstrate the high CFPP temperature of biodiesel obtained from animal fats (Muniyappa et al., 1996; Canoira et al., 2008; Da Cunha et al., 2009; Teixeira et al., 2009; İşler et al., 2010; Encinar et al., 2011; Mata et al., 2011a; Table 5 Physical-chemical properties of soybean biodiesel and bovine tallow biodiesel. Property
BOS
BSB
Limit
Standard
Aspect Acidity Index (mg KOH/g) Water content (ppm) Specific Mass at 20 °C (kg / m3) Iodine content (g I2/100 g) IP (hours) CFPP (°C) Ester content (% mass) Methanol content (% mass) Flash point (°C)
LII 0.18 483 885 117 4.33 −4 96.5 3.5 × 10−7 121
LII 0.12 495 874 31 9.79 15 94.7 7.1 × 10−7 139
LII 0.50 (max.) 500 (max.) 850-900 – 8h (min) 19 (max.) 96.5% (min) 0.20% (max) 100 (min.)
– EN14104 EN ISO3104 EN ISO3675 EN14111 EN14112 EN116 EN14103 EN14110 EN ISO3679
5
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Fig. 5. IP and CFPP of soybean methyl biodiesel, bovine tallow methyl biodiesel and BOS/BSB blends.
4. Conclusion
value in 5.87 h. The value of the induction time of M7 even though it was close to the established limit had not yet reached the minimum necessary. However, M8 samples with 45% and M9 with 50% BSB were able to increase the IP value to 6.33 and 6.71 h, respectively. The M9 mixture showed the highest oxidative stability. The analysis of the induction times showed that mixtures containing from 45% of BSB meet the established parameters, and that with 50% of BSB the mixture becomes more resistant to oxidation. These results are consistent since the decrease in the percentage of BOS also decreased the concentration of unsaturated esters and increased the percentage of saturated esters derived from BSB. As for the CFPP, it was observed that as the proportion of BSB increases, this value increases on average by a degree celsius to every 5% of BSB. Starting with -2.0 °C for the mixture M1, with 10% BSB and ending with 7.0 °C in the M9 mixture with 50% of each biodiesel. The M9 mixture was the one with the highest CFPP temperature, showing the most susceptible to crystallize. This result is quite consistent, since this M9 sample, with 50% BSB, is the one with the highest proportion of saturated esters. Thus, additions of BSB in BOS below 50% contributes to the increase in IP and CFPP improving these physicochemical properties. The increase in IP increases its oxidation resistance, extending its service life, and an increase in CFPP temperature is required to prevent its solidification and crystallization in countries facing harsh winters with low temperatures. Dunn, R. O., 2005 evaluated the oxidative stability of the FAME of soybean oil (Dunn, 2005). Jain, S., & Sharma, M. P., 2010 have reviewed several available studies in which the OS of biodiesel from various raw materials and blends were evaluated (Jain and Sharma, 2010). Carvalho, A. L., et al., 2013 performed an experimental design of biodiesel mixtures to evaluate the OS of samples containing soybean biodiesel with tallow and castor biodiesel (Carvalho et al., 2013). Serrano, M., et al., 2014 studied biodiesel blends obtained from different vegetable oils in order to obtain a mixture that had OS and cold flow properties that EN14214 (Serrano et al., 2014). Viegas, I. M., et al., 2018 studied several blends of biodiesel from soybean, corn, babassu and palm, seeking an increase in OS using mixing design and polynomial modeling (Viegas et al., 2018). Other studies evaluate some methodologies to improve the CFPP of bovine tallow biodiesel (Imahara et al., 2006; Cunha et al., 2013b; Mata et al., 2011b; Doğan and Temur, 2013; Okwundu et al., 2019; Magalhães et al., 2019; Srinivasan et al., 2019).
The mixtures of soybean methyl biodiesel (BOS) and bovine tallow methyl biodiesel (BSB) showed to be able to increase the oxidative stability (OS) by measuring the induction period (IP) of biodiesel as the proportion of BSB increases. That is, as the percentage of saturated esters increases, resistance to oxidative processes increases, and the best results are obtained with 45% and 50% of BSB. Then in this case a mixture containing 50% BSB, which has the highest IP, is recommended. It was observed that the increase in the BSB ratio causes an increase in the cold filter plugging point (CFPP), due to the percentage decrease of unsaturated esters from BOS, and a percentage increase of saturated esters from the BSB. References Adewale, P., Dumont, M.-J., Ngadi, M., 2015. Recent trends of biodiesel production from animal fat wastes and associated production techniques. Renewable Sustainable Energy Rev. 45, 574–588. https://doi.org/10.1016/j.rser.2015.02.039. Anguebes-Franseschi, F., Bassam, A., Abatal, M., May Tzuc, O., Aguilar-Ucán, C., WakidaKusunoki, A.T., San Pedro, L.C., 2019. Physical and chemical properties of biodiesel obtained from amazon sailfin catfish (Pterygoplichthys pardalis) biomass oil. J. Chem. 2019, 1–12. https://doi.org/10.1155/2019/7829630. Basu, H.N., and Norris, M.E. (1996) Process for Production of Esters for Use As a Diesel Fuel Substitute Using a Non-alkaline Catalyst, US Patent 5,525,126. Canoira, L., Rodríguez-Gamero, M., Querol, E., Alcántara, R., Lapuerta, M., Oliva, F., 2008. Biodiesel from low-grade animal fat: production process assessment and biodiesel properties characterization. Ind. Eng. Chem. Res. 47 (21), 7997–8004. https:// doi.org/10.1021/ie8002045. Carvalho, A.L., Santana, S.M.F., Silva, C.S., Pepe, I.M., Bezerra, M.A., Aragão, L.M., Quintella, C.M., Teixeira, L.S.G., 2013. Evaluation of the oxidative stability of biodiesel blends from soybean, tallow and castor bean using experimental mixture design. J. Braz. Chem. Soc. 24 (8), 1373–1379. https://doi.org/10.5935/0103-5053. 20130174. Costa Neto, P.R., Balparda Caro, M.S., Mazzuco, L.M., Nascimento, Mda G., 2004. Quantification of soybean oil ethanolysis with 1 H NMR. J. Am. Oil Chem. Soc. 81 (12), 1111–1114. https://doi.org/10.1007/s11746-004-1026-0. Cunha, A., Feddern, V., De Prá, M.C., Higarashi, M.M., de Abreu, P.G., Coldebella, A., 2013a. Synthesis and characterization of ethylic biodiesel from animal fat wastes. Fuel 105, 228–234. https://doi.org/10.1016/j.fuel.2012.06.020. Cunha, A., Feddern, V., De Prá, M.C., Higarashi, M.M., de Abreu, P.G., Coldebella, A., 2013b. Synthesis and characterization of ethylic biodiesel from animal fat wastes. Fuel 105, 228–234. https://doi.org/10.1016/j.fuel.2012.06.020. Da Cunha, M.E., Krause, L.C., Moraes, M.S.A., Faccini, C.S., Jacques, R.A., Almeida, S.R., Caramão, E.B., 2009. Beef tallow biodiesel produced in a pilot scale. Fuel Process. Technol. 90 (4), 570–575. https://doi.org/10.1016/j.fuproc.2009.01.001. Doğan, T.H., Temur, H., 2013. Effect of fractional winterization of beef tallow biodiesel on the cold flow properties and viscosity. Fuel 108, 793–796. https://doi.org/10. 1016/j.fuel.2013.02.028. Dunn, R.O., 2005. Oxidative stability of soybean oil fatty acid methyl esters by oil
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O.N. de Freitas, et al. stability index (OSI). J. Am. Oil Chem. Soc. 82 (5), 381–387. https://doi.org/10. 1007/s11746-005-1081-6. Encinar, J.M., Sánchez, N., Martínez, G., García, L., 2011. Study of biodiesel production from animal fats with high free fatty acid content. Bioresour. Technol. 102 (23), 10907–10914. https://doi.org/10.1016/j.biortech.2011.09.068. Freedman, B., Pryde, E.H., Mounts, T.L., 1984. Variables affecting the yields of fatty esters from transesterified vegetable oils. J. Am. Oil Chem. Soc. 61 (10), 1638–1643. https://doi.org/10.1007/bf02541649. Freire, L.M.S., Filho, J.R.C., Moura, C.V.R., Soledade, L.E.B., Stragevitch, L., Cordeiro, Â.M.T.M., Souza, A.G., 2012. Evaluation of the oxidative stability and flow properties of quaternary mixtures of vegetable oils for biodiesel production. Fuel 95, 126–130. https://doi.org/10.1016/j.fuel.2011.11.014. Gelbard, G., Brès, O., Vargas, R.M., Vielfaure, F., Schuchardt, U.F., 1995. 1 H nuclear magnetic resonance determination of the yield of the transesterification of rapeseed oil with methanol. J. Am. Oil Chem. Soc. 72 (10), 1239–1241. https://doi.org/10. 1007/bf02540998. Imahara, H., Minami, E., Saka, S., 2006. Thermodynamic study on cloud point of biodiesel with its fatty acid composition. Fuel 85 (12-13), 1666–1670. https://doi.org/ 10.1016/j.fuel.2006.03.003. İşler, A., Sundu, S., Tüter, M., Karaosmanoğlu, F., 2010. Transesterification reaction of the fat originated from solid waste of the leather industry. Waste Manag. 30 (12), 2631–2635. https://doi.org/10.1016/j.wasman.2010.06.005. Jagadale, S.S., Jugulkar, Lalitkumar, 2012. Production and analysis of chemical properties of chicken fat based biodiesel and its various blends. Int. J. Eng. Res. Dev. 1, 34–37. Jain, S., Sharma, M.P., 2010. Stability of biodiesel and its blends: a review. Renewable Sustainable Energy Rev. 14 (2), 667–678. https://doi.org/10.1016/j.rser.2009.10. 011. Kirubakaran, M., Arul Mozhi Selvan, V., 2018. A comprehensive review of low cost biodiesel production from waste chicken fat. Renewable Sustainable Energy Rev. 82, 390–401. https://doi.org/10.1016/j.rser.2017.09.039. Knothe, G., 2010. Biodiesel and renewable diesel: a comparison. Prog. Energy Combust. Sci. 36 (3), 364–373. https://doi.org/10.1016/j.pecs.2009.11.004. Knothe, G., Steidley, K.R., 2005. Lubricity of components of biodiesel and petrodiesel. The origin of biodiesel lubricity†. Energy Fuels 19 (3), 1192–1200. https://doi.org/ 10.1021/ef049684c. Knothe, G., Gerpen, J.V., Krahl, J., Ramos, L.P., 2006. Manual De Biodiesel. Editora Edgard Blücher 1° edição, 333 p. Liu, K.S., 1994. Preparation of fatty acid methyl esters for gas-chromatographic analysis of lipids in biological materials. J. Am. Oil Chem. Soc. 71 (11), 1179–1187. https:// doi.org/10.1007/bf02540534. Lôbo, I.P., Ferreira, S.L.C., Cruz, R.Sda, 2009. Biodiesel: parâmetros de qualidade e métodos analíticos. Química Nova 32 (6), 1596–1608. https://doi.org/10.1590/ s0100-40422009000600044. Magalhães, A.M.S., Pereira, E., Meirelles, A.J.A., Sampaio, K.A., Maximo, G.J., 2019. Proposing blends for improving the cold flow properties of ethylic biodiesel. Fuel 253, 50–59. https://doi.org/10.1016/j.fuel.2019.04.129. Mata, T.M., Cardoso, N., Ornelas, M., Neves, S., Caetano, N.S., 2011a. Evaluation of two purification methods of biodiesel from beef tallow, pork lard, and chicken fat. Energy Fuels 25 (10), 4756–4762. https://doi.org/10.1021/ef2010207. Mata, T.M., Cardoso, N., Ornelas, M., Neves, S., Caetano, N.S., 2011b. Evaluation of two purification methods of biodiesel from beef tallow, pork lard, and chicken fat. Energy
Fuels 25 (10), 4756–4762. https://doi.org/10.1021/ef2010207. Mendes, A.P.A., Costa, R.C., 2010. Mercado brasileiro de biodiesel e perspectivas futuras. BNDES Setorial, Rio de Janeiro 31, 253–279. Meneghetti, S.M.P., Meneghetti, M.R., Serra, T.M., Barbosa, D.C., Wolf, C.R., 2007. Biodiesel production from vegetable oil mixtures: cottonseed, soybean, and Castor oils. Energy Fuels 21 (6), 3746–3747. https://doi.org/10.1021/ef070039q. Monteiro, M., Ambrozin, A., Liao, L., Ferreira, A., 2008. Critical review on analytical methods for biodiesel characterization. Talanta 77 (2), 593–605. https://doi.org/10. 1016/j.talanta.2008.07.001. Muniyappa, P.R., Brammer, S.C., Noureddini, H., 1996. Improved conversion of plant oils and animal fats into biodiesel and co-product. Bioresour. Technol. 56 (1), 19–24. https://doi.org/10.1016/0960-8524(95)00178-6. Okwundu, O.S., El-Shazly, A.H., Elkady, M., 2019. Comparative effect of reaction time on biodiesel production from low free fatty acid beef tallow: a definition of product yield. SN Appl. Sci. 1 (2). https://doi.org/10.1007/s42452-018-0145-1. Pereira, G.G., Garcia, R.K.A., Ferreira, L.L., Barrera-Arellano, D., 2017. Soybean and soybean/beef-tallow biodiesel: a comparative study on oxidative degradation during long-term storage. J. Am. Oil Chem. Soc. 94 (4), 587–593. https://doi.org/10.1007/ s11746-017-2962-6. Ramos, M.J., Fernández, C.M., Casas, A., Rodríguez, L., Pérez, Á., 2009. Influence of fatty acid composition of raw materials on biodiesel properties. Bioresour. Technol. 100 (1), 261–268. https://doi.org/10.1016/j.biortech.2008.06.039. Serrano, M., Oliveros, R., Sánchez, M., Moraschini, A., Martínez, M., Aracil, J., 2014. Influence of blending vegetable oil methyl esters on biodiesel fuel properties: oxidative stability and cold flow properties. Energy 65, 109–115. https://doi.org/10. 1016/j.energy.2013.11.072. Silva, A.A.L., Dias Santos, A.G., Di Souza, L., Da Silva Caldeira, V.P., Luz Júnior, G.E., Araújo, A.S., 2015. Síntese e Caracterização de Biodiesel de Sebo Bovino e de sua mistura B10. Orbital - Electron. J. Chem. 7 (1). https://doi.org/10.17807/orbital. v7i1.680. Srinivasan, G.R., Shankar, V., Jambulingam, R., 2019. Experimental study on influence of dominant fatty acid esters in engine characteristics of waste beef tallow biodiesel. Energy Explor. Exploit. 37 (3), 1098–1124. https://doi.org/10.1177/ 0144598718821791. Teixeira, L.S.G., Assis, J.C.R., Mendonça, D.R., Santos, I.T.V., Guimarães, P.R.B., Pontes, L.A.M., Teixeira, J.S.R., 2009. Comparison between conventional and ultrasonic preparation of beef tallow biodiesel. Fuel Process. Technol. 90 (9), 1164–1166. https://doi.org/10.1016/j.fuproc.2009.05.008. Teixeira, L.S.G., Couto, M.B., Souza, G.S., Filho, M.A., Assis, J.C.R., Guimarães, P.R.B., Teixeira, J.S.R., 2010. Characterization of beef tallow biodiesel and their mixtures with soybean biodiesel and mineral diesel fuel. Biomass Bioenergy 34 (4), 438–441. https://doi.org/10.1016/j.biombioe.2009.12.007. Viegas, I.M.A., Barradas Filho, A.O., Marques, E.P., Pereira, C.F., Marques, A.L.B., 2018. Oxidative stability of biodiesel by mixture design and a four-component diagram. Fuel 219, 389–398. https://doi.org/10.1016/j.fuel.2018.01.124. Wyatt, V.T., Hess, M.A., Dunn, R.O., Foglia, T.A., Haas, M.J., Marmer, W.N., 2005. Fuel properties and nitrogen oxide emission levels of biodiesel produced from animal fats. J. Am. Oil Chem. Soc. 82 (8), 585–591. https://doi.org/10.1007/s11746-005-1113-2. Yuan, M.-H., Chen, Y.-H., Chen, J.-H., Luo, Y.-M., 2017. Dependence of cold filter plugging point on saturated fatty acid profile of biodiesel blends derived from different feedstocks. Fuel 195, 59–68. https://doi.org/10.1016/j.fuel.2017.01.054.
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Evaluation of the oxidative stability and cold filter plugging point of soybean methyl biodiesel/bovine tallow methyl biodiesel blends
T
Osmar Nunes de Freitasa, Rafael Cardoso Rialb, , Leandro Fontoura Cavalheiroa, Joyce Mara dos Santos Barbosaa, Carlos Eduardo Domingues Nazárioa, Luíz Henrique Vianaa ⁎
a b
Instituto de Química, Universidade Federal de Mato Grosso do Sul, 79070-900 Campo Grande MS, Brazil Instituto Federal de Mato Grosso do Sul, 79750-000, Nova Andradina MS, Brazil
ARTICLE INFO
ABSTRACT
Keywords: Soybean methyl biodiesel Bovine tallow methyl biodiesel Oxidative stability Cold filter plugging point Blends
The objective of the present work was to study the oxidative stability (OS) estimated from the induction period (IP) and the cold filter plugging point (CFPP) of blends made with different proportions of soybean methyl biodiesel (BOS) and bovine tallow methyl biodiesel (BSB). BOS is poorly resistant to oxidation because its composition is predominantly unsaturated esters, but it has a satisfactory cold filter plugging point. The BSB is composed of saturated esters and of the lower carbon chain and thus has good oxidation stability values, but has poor CFPP values. Thus, BOS / BSB mixtures in different proportions were made to evaluate the ideal amount of the mixture in which it was possible to obtain IP and CFPP properties in satisfactory values by the legislation. The mixtures started at 10% BSB and 90% BOS and was increased 5% up to the 50% percentage of each biodiesel in each blend. Samples with 45% and 50% BSB had oxidative stability above the minimum required by law, and all blends had the CFPP value within the legal values.
1. Introduction Biodiesel is a biodegradable fuel made from renewable raw materials, consisting of alkyl esters, which uses vegetable oils or animal fats as the starting material for the transesterification and / or esterification reaction, and can be used on diesel engines with compression ignition, mixed to mineral oil in various proportions or pure (Mendes and Costa, 2010). Biodiesel has advantages over diesel oil, as it is less polluting, has higher cetane number, flash point and lubricity (Knothe and Steidley, 2005; Knothe, 2010). In Brazil, the two main sources used in the country for the production of biodiesel are soybean oil and bovine tallow, which together account for approximately 91% of all biodiesel produced in the country (Knothe et al., 2006). The National Agency of Petroleum, Natural Gas and Biofuels - ANP - regulates the fuel and biofuels sector in Brazil and recommends - through ANP Resolution No. 45/2014 - that all biodiesel sold in the country meets some quality requirements. Soybean biodiesel meets the specifications of quality, but has the disadvantage of having a low oxidative stability (OS) due to its composition being approximately 75% from unsaturated fatty acids (Meneghetti et al., 2007). On the other hand, bovine tallow biodiesel has few unsaturated fatty acids (Silva et al., 2015). Therefore, bovine tallow biodiesel has a higher
⁎
oxidative stability and lower cold filter plugging point (CFPP) (Wyatt et al., 2005). Some CFPP and OS studies between BOS/BSB mixtures are available in the literature. Teixeira, L. S. G., et al., 2010 evaluated some physicochemical properties, including CFPP, of mixtures of soybean methyl biodiesel/beef tallow methyl biodiesel, ranging from 10 to 90% (v/v), and the values of CFPP increased as the proportion of beef tallow increased in the mixture (Teixeira et al., 2010). Pereira, G. G., et al., 2017 studied the oxidative stability in soybean/beef tallow biodiesel blends in the proportion 70/30 and 50/50 (w/w) during the storage of 350 days and these mixtures showed higher resistance oxidation when compared to oxidative stability of soybean biodiesel (Pereira et al., 2017). On the other hand, these two studies did not simultaneously evaluate these two physicochemical properties in BOS/BSB mixtures, which vary depending on the process of obtaining these biofuels. Therefore, it is important to evaluate these two physicochemical properties simultaneously in BOS / BSB mixtures obtained under the same reaction conditions. In the presente work evaluated the oxidative stability by measuring the induction period (PI) and CFPP of different mixtures with different amounts of soybean methyl biodiesel and tallow bovine biodiesel in order to investigate the possibility of producing a mixture that could
Corresponding author. E-mail address: [email protected] (R. Cardoso Rial).
https://doi.org/10.1016/j.indcrop.2019.111667 Received 23 June 2019; Received in revised form 4 August 2019; Accepted 14 August 2019 0926-6690/ © 2019 Elsevier B.V. All rights reserved.
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increase IP value in relation to soybean methyl biodiesel and the CFPP value of beef tallow methyl biodiesel was decreased to meet the quality requirements available in current regulations that are necessary to ensure a quality biodiesel.
Table 1 Chromatographic Parameters GC - FID to analyze the chemical composition of BSB and BOS. Injector and detector parameters Injection volume Injector temperature (°C) Detector Injection mode Split Reason Detector temperature (°C) Oven parameters Heating rate (°C/min) Isotherm (min.) Total Running Time (min.) Temperature (°C) Drag gas Flow
2. Methodology 2.1. Obtaining bovine tallow metyl biodiesel The bovine tallow was purchased at a supermarket in the city of Campo Grande - MS - Brazil, and after cleaning, it was placed in a container with heating for 1 h and 120 °C to obtain fat. After melting, the filtration and separation of the water were made. In order to obtain the biodiesel, the bovine tallow was heated at 85 °C in the molar ratio tallow bovine: methyl alcohol 1:6 mol/mol, using 0.5% sodium hydroxide (NaOH) as catalyst, with a reaction time of 1 h under stirring at 400 rpm. The reaction was monitored by thin layer chromatography (CCD) and after the end of the reaction time, the biodiesel was separated from the glycerine, washed and then dried using anhydrous magnesium sulfate, thus obtaining the bovine tallow methyl biodiesel (BSB).
4 10 52 80 Helium 1 mL/min
2.5. Physico-chemical Properties of bovine tallow, soybean oil, BSB and BOS For the physical chemical characterization of the raw materials, the following parameters were measured: Acidity Index (EN14104), Water content (ASTM D 6304), Iodine value (EN 14111) and Specific Mass at 20 °C (ASTM D 4052).
2.2. Obtaining soybean methyl biodiesel To obtain the soybean methyl biodiesel (BOS), the soybean oil was maintained at a temperature in the range of 35 °C–40 °C, sodium hydroxide (NaOH) was used in a proportion of 1% by oil mass. The molar ratio of soybean oil: methanol was 1: 6 mol mol and the reaction time was 40 min. The reaction was monitored by CCD and after the reaction time was over, the BOS was washed to facilitate the separation of the glycerin, rotavaporated and then dried using anhydrous magnesium sulfate.
2.6. BOS: BSB blends As the production in Brazil of BOS is higher than BSB, mixtures with more than 50% BSB would make it impossible to meet this need. Thus, the BOS and BSB samples were mixed in varying amounts to form the mixtures, starting initially with 90% BOS and 10% BSB, and increasing 5% BSB with each new blend to reach 50% of each biodiesel. The volume of the mixtures was determined by the amount to be used in the analyzes. The mixtures obtained are detailed in Table 2. After the mixtures, aliquots of the formed blends were submitted to OS and CFPP analysis and the results were evaluated comparing with the results of the pure biodiesel and the values indicated by the legislation.
2.3. Characterization of bovine tallow, soybean oil, BSB and BOS Aliquots of bovine tallow, soybean oil, BSB and BOS were routed to H NMR spectra. NMR spectra were performed on a Bruker spectrometer of 7.05 T, model DPX300 (300.13 MHz for hydrogen frequency), using deuterated chloroform (CDCl3) as solvent.
1
2.7. Evaluation of oxidative stability of biodiesel and blends Samples of BOS, BSB and blends were analyzed according to the Rancimat® method, according to European Standard EN 14112, using METROHM equipment (Model Rancimat 873), under heating at 110 °C and constant flow of air 10 Lh−1. The temperature correction factor (ΔT) was set at 0.9 °C as recommended by EN14112. The amount of sample used was 3.0 g.
2.4. Chemical composition of bovine tallow, soybean oil, BSB and BOS To determine and quantify the chemical composition of methyl esters of fatty acids that compose the BSB and BOS was used gas chromatography coupled to flame ionization detector (GC-FID) with internal standard for calibration. The procedure adopted is European standard EN 14103. The amount of 250 mg of each sample was mixed with 5 mL of 10 mg / mL methyl heptadecanoate solution (internal standard) and injected into the chromatograph. A Varian CP-3800 chromatograph with automatic injector and flame ionization detector (FID) was used to perform the procedure. The column used was a BPX 70 (SGE) measuring 30 m in length, 0.25 mm internal diameter and 0.25 μm film. Chromatographic parameters are shown in Table 1. A previous injection with chromatographic standards was performed to identify the peaks C14, C17 and C24:1 to define the quantification interval and to identify the retention time of the internal standard (C17). The ester content was determined by Equation (1): TE = {[(_A) - API / API] x [CPI x VPI / m]} x 100
1 μL 200 FID Split 1:100 250
2.8. Cold filter clogging point of biodiesel and blends To determine this property, the procedure described in ASTM Table 2 Optimization of biodiesel mixtures of soybean biodiesel and bovine tallow biodiesel for blends composition.
(1)
TE is the ester content; _A is the sum of the areas of all peaks; API is the area of the internal standard; CPI is the concentration of the internal standard; VPI is the volume of internal standard solution; m is the mass of the sample. 2
Sample
% BOS
Volume
% BSB
Volume
V. Total
M1 M2 M3 M4 M5 M6 M7 M8 M9
90% 85% 80% 75% 70% 65% 60% 55% 50%
45.0 mL 42.5 mL 40.0 mL 37.5 mL 35.0 mL 32.5 mL 30.0 mL 27.5 mL 25.0 mL
10% 15% 20% 25% 30% 35% 40% 45% 50%
5.0 mL 7.5 mL 10.0 mL 12.5 mL 15.0 mL 17.5 mL 20.0 mL 22.5 mL 25.0 mL
50.0 mL 50.0 mL 50.0 mL 50.0 mL 50.0 mL 50.0 mL 50.0 mL 50.0 mL 50.0 mL
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As the specific mass of the oil is greater than that of the tallow bovine, we can predict that the soybean oil has an amount of esters with a carbonic chain greater than the bovine tallow.
Table 3 Physical-chemical properties of soybean oil and bovine tallow. Property
Unity
Soybean oil
Bovine tallow
Acidity level % Acidity Water content Iodine value Especific mass
mg KOH/g % % g de I2/ 100 g g. cm−3
0.1510 0.07 0.09 115.35 0.919
0.0803 0.04 0.10 27.92 0.901
3.2. Production of soybean methyl biodiesel and bovine tallow methyl biodiesel Gelbard, G., et al., 1995 was one of the pioneers in using 1H nuclear magnetic resonance spectroscopy to analyze the yields of the transesterification reaction (Gelbard et al., 1995). Some authors state that 1H NMR is faster and simpler when compared to gas chromatography and liquid chromatography (Costa Neto et al., 2004). Despite this, other characterization techniques are available and are used to verify the transesterification reaction (Monteiro et al., 2008). By obtaining and analyzing the 1H NMR spectra it is possible to prove the formation of the biodieses and verify their purity. In the 1H NMR spectrum of BOS (Fig. 2) the following signals were observed: a singlet at δ =3.6 ppm which can be attributed to the methyl hydrogens of the ester group, as they typically appear in the region between δ = 3.5–3.7 ppm; a triplet at δ =2.24 ppm attributed to α-carbonyl methylene hydrogens; and a mutiplet in the region of δ = 2.0 to δ =1.0 ppm referring to the methylene groups of the esters carbon chain. The signal at δ =5.3 ppm refers to the olefinic protons and their low intensity is related to the low amount of unsaturated esters present. Compared with the 1H NMR spectrum of the soybean oil (Fig. 1) the total disappearance of the chemical displacement relative to the glycerides at δ = 4.1–4.3 ppm can be observed. The absence of these signals in the BOS spectrum confirms that the total consumption of the oil used as raw material occurred. In the bovine tallow spectrum (Fig. 3), the olefinic protons, in δ =5.31 ppm, appear between δ = 5.24 and 5.34 ppm; the methylene protons of glycerol (triglycerides) appear in the range of δ = 4.07–4.31 ppm represented by dublo-dubletes; the methyl protons are observed as triplet at δ =0.85 ppm; the alpha-carbonyl protons are observed as triplet at δ =2.28 ppm. In the 1H NMR spectrum of BSB (Fig. 4) the following signals were observed: a singlet at δ =3.63 ppm which can be attributed to the methyl hydrogens of the ester group, as these appear in the region between δ = 3, 5 - 3.7 ppm; a triplet at δ =2.27 ppm attributed to α-carbonyl methylene hydrogens; and a mutiplet in the region of δ = 2.0 to δ =1.0 ppm referring to the methylene groups of the esters carbon chain. The signal at δ =5.31 ppm refers to the olefinic protons and their low intensity is related to the low amount of unsaturated esters present, and we also observed the methyl protons
D6371 was used. 45 mL of each sample is precooled under standard conditions and at 1 °C intervals is suctioned by a pipette attached to a controlled vacuum system having a 45 μm metal mesh. The procedure is carried out until, due to the solidification of the sample, it can not flow into the vessel within 60 s. For the determination of this parameter the equipment used was the Automated CFPP Tester model AFP-101 of the mark TANAKA Scientific Limited. 3. Results and discussions 3.1. Physical - chemical properties and chemical composition of soybean oil and bovine tallow Soybean oil and bovine tallow had their properties evaluated for the selection of the most appropriate method for obtaining biodiesel. The results obtained are shown in Table 3. For soybean oil the acid value was 0.1510 mg KOH/g and the acid percentage was 0.07%. The values measured in bovine tallow were 0.0803 mg KOH/g for the acid number and the acid percentage was 0.04%. As the values of soybean oil and acidity of tallow were less than 0.5%, it was possible to choose alkaline transesterification in one step to obtain biodiesel, considering that the conversion of oils and fats presents a higher esters formation, when raw materials have a lower acidity index (Freedman et al., 1984). The water content in the oil and bovine tallow was also evaluated because the presence of moisture in the raw material decreases the biodiesel yield because it favors the saponification (Liu, 1994; Basu and Norris, 1996). The values observed were for soybean oil 0.090% and bovine tallow, 0.100%. The iodine value is a measure of the unsaturations present in the raw material and indicates its rate of degradation (Freire et al., 2012) and measured value for soybean oil was 115.35 g of I2/100 g of sample, while the bovine tallow had 27.92 g of I2/100 g of sample. The specific mass of the soybean oil was 0.919 g.cm−3 and 0.901 g.cm−3 for bovine tallow.
Fig. 1. 1H-NMR spectrum (300 MHz, CDCl3) of Soybean Oil. 3
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Fig. 2. 1H–NMR spectrum (300 MHz, CDCl3) of soybean methyl biodiesel (BOS).
as triplet at δ =0.85 ppm. Comparing the 1H NMR spectra of bovine tallow with the BSB spectrum, the total disappearance of the chemical displacement for the glycerides in δ = 4.1–4.3 ppm can be observed.
2009 studied the influence of the composition of fatty acids on the physical and chemical properties of biodiesel with high amounts of unsaturated esters presented the lowest oxidative stability and the biodieses with higher amounts of saturated esters had the point of CFPP the worst results (Ramos et al., 2009). Yuan, M. H., et al., 2017 carried out a study to find a statistically combination based on the composition of fatty acid methyl esters to predict CFPP (Yuan et al., 2017). To verify the quality of BOS and BSB the following physico-chemical properties were evaluated: Acid index, water content, iodine value, specific mass at 20 °C, CFPP and IP. It was also evaluated its apparent appearance that should be clear and free of impurities (LII). All results obtained are in Table 5 The physico-chemical properties of BOS and BSB showed that the biodiesel obtained met most of the quality requirements, except for the ester content for BSB which was 94.7% while the minimum required value was 96.5%. This shows the difficulty in the transesterification procedure, where several adjustments were necessary in the procedure, until we reached the best factors with the use of 0.5% catalyst and
3.3. Chemical composition of BOS and BSB and physical chemical parameters To quantify the fatty acid methyl esters (FAME) formed after the BOS and BSB transesterification reactions, gas chromatography coupled to the flame ionization detector (GC - FID) was used and the percentages are presented in Table 4. The total unsaturated esters of BOS was 84.0% and that of saturated esters was 15.98%. The BSB chemical composition showed a total of unsaturated esters of 41.33% and saturated esters of 58.58%. The higher amount of saturated esters than unsaturated is concerned with the inference about this biodiesel having difficulty meeting the parameters of CFPP, and also about its high oxidative stability since the saturated esters, are more resistant to oxidation. Ramos, M. J., et al.,
Fig. 3. 1H-NMR spectrum (300 MHz, CDCl3) of bovine tallow. 4
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Fig. 4. 1H-NMR spectrum (300 MHz, CDCl3) of bovine tallow biodiesel (BSB).
Jagadale and Jugulkar, 2012; Cunha et al., 2013a; Adewale et al., 2015; Kirubakaran and Arul Mozhi Selvan, 2018; Anguebes-Franseschi et al., 2019).
Table 4 Chemical composition of soybean methyl biodiesel and bovine tallow methyl biodiesel. FAME
BOS Concentration (%)
BSB Concentration (%)
(C14:0) (C15:0) (C16:0) (C16:1) (C17:0) (C18:0) (C18:1) (C18:2) (C18:3) (C20:0) (C22:0) Saturated FAME Monounsaturated FAME Polyunsaturated FAME Unsaturated FAME Total FAME
0.12 – 10.91 – – 3.15 26.65 51.76 5.59 0.80 1.00 15.98 26.65 57.35 84.00 99.98
5.13 1.20 25.04 3.82 3.08 22.76 34.51 2.60 – 1.37 – 58.58 38.33 2.60 40.93 99.51
3.4. Evaluation of the CFPP and OS of BOS: BSB blends The BOS presented the induction time of 4.33 hs confirming what the literature says about the difficulty of this biodiesel in meeting the parameters of the legislation that is of at least 8,00 h. This low stability of soybean methyl biodiesel is attributed to the fact that most of its esters (62%) are unsaturated. The BSB presented an IP of 9.79 h, which is above the minimum value required by the legislation, which is 8.0 h. This high stability of the BSB is attributed to the fact that most of its constituent esters are saturated. Biodiesel partially solidifies or loses its fluidity at low temperatures, suspending the fuel flow, clogging the filtration system, making it difficult to start the engine (Lôbo et al., 2009). Thus, CFPP is the measure of the lowest temperature at which a liquid can flow without causing problems. In cold climate regions, this is an important parameter to be determined because this procedure simulates the temperature at which the fuel can freeze in the engines. The CFPP values presented for the BOS were-4.0 °C and the BSB, 15 °C. Fig. 5 shows the IP and CFPP values for each of the mixtures and also for the two pure biodieses The increase in OS of the blend was evident as the proportion of BSB was increased. The result of the IP of sample M2, which contained 85% of BOS and 15% of BSB, was 4.43 h, just slightly above the value of pure BOS. But on average the BSB ratio was increased, the OS was increasing and at 40% BSB, the induction time was already close to the accepted
reaction temperature of 85 °C. In addition, the low oxidative stability of soybean-methyl biodiesel was evidenced, which did not reach the minimum IP parameter of 8.0 h established by the ANP, whose value was 4.33 h. It was also confirmed the ease of the biodiesel of bovine tallow to crystallize, because it was obtained the temperature of 15 °C. Other studies demonstrate the high CFPP temperature of biodiesel obtained from animal fats (Muniyappa et al., 1996; Canoira et al., 2008; Da Cunha et al., 2009; Teixeira et al., 2009; İşler et al., 2010; Encinar et al., 2011; Mata et al., 2011a; Table 5 Physical-chemical properties of soybean biodiesel and bovine tallow biodiesel. Property
BOS
BSB
Limit
Standard
Aspect Acidity Index (mg KOH/g) Water content (ppm) Specific Mass at 20 °C (kg / m3) Iodine content (g I2/100 g) IP (hours) CFPP (°C) Ester content (% mass) Methanol content (% mass) Flash point (°C)
LII 0.18 483 885 117 4.33 −4 96.5 3.5 × 10−7 121
LII 0.12 495 874 31 9.79 15 94.7 7.1 × 10−7 139
LII 0.50 (max.) 500 (max.) 850-900 – 8h (min) 19 (max.) 96.5% (min) 0.20% (max) 100 (min.)
– EN14104 EN ISO3104 EN ISO3675 EN14111 EN14112 EN116 EN14103 EN14110 EN ISO3679
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Fig. 5. IP and CFPP of soybean methyl biodiesel, bovine tallow methyl biodiesel and BOS/BSB blends.
4. Conclusion
value in 5.87 h. The value of the induction time of M7 even though it was close to the established limit had not yet reached the minimum necessary. However, M8 samples with 45% and M9 with 50% BSB were able to increase the IP value to 6.33 and 6.71 h, respectively. The M9 mixture showed the highest oxidative stability. The analysis of the induction times showed that mixtures containing from 45% of BSB meet the established parameters, and that with 50% of BSB the mixture becomes more resistant to oxidation. These results are consistent since the decrease in the percentage of BOS also decreased the concentration of unsaturated esters and increased the percentage of saturated esters derived from BSB. As for the CFPP, it was observed that as the proportion of BSB increases, this value increases on average by a degree celsius to every 5% of BSB. Starting with -2.0 °C for the mixture M1, with 10% BSB and ending with 7.0 °C in the M9 mixture with 50% of each biodiesel. The M9 mixture was the one with the highest CFPP temperature, showing the most susceptible to crystallize. This result is quite consistent, since this M9 sample, with 50% BSB, is the one with the highest proportion of saturated esters. Thus, additions of BSB in BOS below 50% contributes to the increase in IP and CFPP improving these physicochemical properties. The increase in IP increases its oxidation resistance, extending its service life, and an increase in CFPP temperature is required to prevent its solidification and crystallization in countries facing harsh winters with low temperatures. Dunn, R. O., 2005 evaluated the oxidative stability of the FAME of soybean oil (Dunn, 2005). Jain, S., & Sharma, M. P., 2010 have reviewed several available studies in which the OS of biodiesel from various raw materials and blends were evaluated (Jain and Sharma, 2010). Carvalho, A. L., et al., 2013 performed an experimental design of biodiesel mixtures to evaluate the OS of samples containing soybean biodiesel with tallow and castor biodiesel (Carvalho et al., 2013). Serrano, M., et al., 2014 studied biodiesel blends obtained from different vegetable oils in order to obtain a mixture that had OS and cold flow properties that EN14214 (Serrano et al., 2014). Viegas, I. M., et al., 2018 studied several blends of biodiesel from soybean, corn, babassu and palm, seeking an increase in OS using mixing design and polynomial modeling (Viegas et al., 2018). Other studies evaluate some methodologies to improve the CFPP of bovine tallow biodiesel (Imahara et al., 2006; Cunha et al., 2013b; Mata et al., 2011b; Doğan and Temur, 2013; Okwundu et al., 2019; Magalhães et al., 2019; Srinivasan et al., 2019).
The mixtures of soybean methyl biodiesel (BOS) and bovine tallow methyl biodiesel (BSB) showed to be able to increase the oxidative stability (OS) by measuring the induction period (IP) of biodiesel as the proportion of BSB increases. That is, as the percentage of saturated esters increases, resistance to oxidative processes increases, and the best results are obtained with 45% and 50% of BSB. Then in this case a mixture containing 50% BSB, which has the highest IP, is recommended. It was observed that the increase in the BSB ratio causes an increase in the cold filter plugging point (CFPP), due to the percentage decrease of unsaturated esters from BOS, and a percentage increase of saturated esters from the BSB. References Adewale, P., Dumont, M.-J., Ngadi, M., 2015. Recent trends of biodiesel production from animal fat wastes and associated production techniques. Renewable Sustainable Energy Rev. 45, 574–588. https://doi.org/10.1016/j.rser.2015.02.039. Anguebes-Franseschi, F., Bassam, A., Abatal, M., May Tzuc, O., Aguilar-Ucán, C., WakidaKusunoki, A.T., San Pedro, L.C., 2019. Physical and chemical properties of biodiesel obtained from amazon sailfin catfish (Pterygoplichthys pardalis) biomass oil. J. Chem. 2019, 1–12. https://doi.org/10.1155/2019/7829630. Basu, H.N., and Norris, M.E. (1996) Process for Production of Esters for Use As a Diesel Fuel Substitute Using a Non-alkaline Catalyst, US Patent 5,525,126. Canoira, L., Rodríguez-Gamero, M., Querol, E., Alcántara, R., Lapuerta, M., Oliva, F., 2008. Biodiesel from low-grade animal fat: production process assessment and biodiesel properties characterization. Ind. Eng. Chem. Res. 47 (21), 7997–8004. https:// doi.org/10.1021/ie8002045. Carvalho, A.L., Santana, S.M.F., Silva, C.S., Pepe, I.M., Bezerra, M.A., Aragão, L.M., Quintella, C.M., Teixeira, L.S.G., 2013. Evaluation of the oxidative stability of biodiesel blends from soybean, tallow and castor bean using experimental mixture design. J. Braz. Chem. Soc. 24 (8), 1373–1379. https://doi.org/10.5935/0103-5053. 20130174. Costa Neto, P.R., Balparda Caro, M.S., Mazzuco, L.M., Nascimento, Mda G., 2004. Quantification of soybean oil ethanolysis with 1 H NMR. J. Am. Oil Chem. Soc. 81 (12), 1111–1114. https://doi.org/10.1007/s11746-004-1026-0. Cunha, A., Feddern, V., De Prá, M.C., Higarashi, M.M., de Abreu, P.G., Coldebella, A., 2013a. Synthesis and characterization of ethylic biodiesel from animal fat wastes. Fuel 105, 228–234. https://doi.org/10.1016/j.fuel.2012.06.020. Cunha, A., Feddern, V., De Prá, M.C., Higarashi, M.M., de Abreu, P.G., Coldebella, A., 2013b. Synthesis and characterization of ethylic biodiesel from animal fat wastes. Fuel 105, 228–234. https://doi.org/10.1016/j.fuel.2012.06.020. Da Cunha, M.E., Krause, L.C., Moraes, M.S.A., Faccini, C.S., Jacques, R.A., Almeida, S.R., Caramão, E.B., 2009. Beef tallow biodiesel produced in a pilot scale. Fuel Process. Technol. 90 (4), 570–575. https://doi.org/10.1016/j.fuproc.2009.01.001. Doğan, T.H., Temur, H., 2013. Effect of fractional winterization of beef tallow biodiesel on the cold flow properties and viscosity. Fuel 108, 793–796. https://doi.org/10. 1016/j.fuel.2013.02.028. Dunn, R.O., 2005. Oxidative stability of soybean oil fatty acid methyl esters by oil
6
Industrial Crops & Products 140 (2019) 111667
O.N. de Freitas, et al. stability index (OSI). J. Am. Oil Chem. Soc. 82 (5), 381–387. https://doi.org/10. 1007/s11746-005-1081-6. Encinar, J.M., Sánchez, N., Martínez, G., García, L., 2011. Study of biodiesel production from animal fats with high free fatty acid content. Bioresour. Technol. 102 (23), 10907–10914. https://doi.org/10.1016/j.biortech.2011.09.068. Freedman, B., Pryde, E.H., Mounts, T.L., 1984. Variables affecting the yields of fatty esters from transesterified vegetable oils. J. Am. Oil Chem. Soc. 61 (10), 1638–1643. https://doi.org/10.1007/bf02541649. Freire, L.M.S., Filho, J.R.C., Moura, C.V.R., Soledade, L.E.B., Stragevitch, L., Cordeiro, Â.M.T.M., Souza, A.G., 2012. Evaluation of the oxidative stability and flow properties of quaternary mixtures of vegetable oils for biodiesel production. Fuel 95, 126–130. https://doi.org/10.1016/j.fuel.2011.11.014. Gelbard, G., Brès, O., Vargas, R.M., Vielfaure, F., Schuchardt, U.F., 1995. 1 H nuclear magnetic resonance determination of the yield of the transesterification of rapeseed oil with methanol. J. Am. Oil Chem. Soc. 72 (10), 1239–1241. https://doi.org/10. 1007/bf02540998. Imahara, H., Minami, E., Saka, S., 2006. Thermodynamic study on cloud point of biodiesel with its fatty acid composition. Fuel 85 (12-13), 1666–1670. https://doi.org/ 10.1016/j.fuel.2006.03.003. İşler, A., Sundu, S., Tüter, M., Karaosmanoğlu, F., 2010. Transesterification reaction of the fat originated from solid waste of the leather industry. Waste Manag. 30 (12), 2631–2635. https://doi.org/10.1016/j.wasman.2010.06.005. Jagadale, S.S., Jugulkar, Lalitkumar, 2012. Production and analysis of chemical properties of chicken fat based biodiesel and its various blends. Int. J. Eng. Res. Dev. 1, 34–37. Jain, S., Sharma, M.P., 2010. Stability of biodiesel and its blends: a review. Renewable Sustainable Energy Rev. 14 (2), 667–678. https://doi.org/10.1016/j.rser.2009.10. 011. Kirubakaran, M., Arul Mozhi Selvan, V., 2018. A comprehensive review of low cost biodiesel production from waste chicken fat. Renewable Sustainable Energy Rev. 82, 390–401. https://doi.org/10.1016/j.rser.2017.09.039. Knothe, G., 2010. Biodiesel and renewable diesel: a comparison. Prog. Energy Combust. Sci. 36 (3), 364–373. https://doi.org/10.1016/j.pecs.2009.11.004. Knothe, G., Steidley, K.R., 2005. Lubricity of components of biodiesel and petrodiesel. The origin of biodiesel lubricity†. Energy Fuels 19 (3), 1192–1200. https://doi.org/ 10.1021/ef049684c. Knothe, G., Gerpen, J.V., Krahl, J., Ramos, L.P., 2006. Manual De Biodiesel. Editora Edgard Blücher 1° edição, 333 p. Liu, K.S., 1994. Preparation of fatty acid methyl esters for gas-chromatographic analysis of lipids in biological materials. J. Am. Oil Chem. Soc. 71 (11), 1179–1187. https:// doi.org/10.1007/bf02540534. Lôbo, I.P., Ferreira, S.L.C., Cruz, R.Sda, 2009. Biodiesel: parâmetros de qualidade e métodos analíticos. Química Nova 32 (6), 1596–1608. https://doi.org/10.1590/ s0100-40422009000600044. Magalhães, A.M.S., Pereira, E., Meirelles, A.J.A., Sampaio, K.A., Maximo, G.J., 2019. Proposing blends for improving the cold flow properties of ethylic biodiesel. Fuel 253, 50–59. https://doi.org/10.1016/j.fuel.2019.04.129. Mata, T.M., Cardoso, N., Ornelas, M., Neves, S., Caetano, N.S., 2011a. Evaluation of two purification methods of biodiesel from beef tallow, pork lard, and chicken fat. Energy Fuels 25 (10), 4756–4762. https://doi.org/10.1021/ef2010207. Mata, T.M., Cardoso, N., Ornelas, M., Neves, S., Caetano, N.S., 2011b. Evaluation of two purification methods of biodiesel from beef tallow, pork lard, and chicken fat. Energy
Fuels 25 (10), 4756–4762. https://doi.org/10.1021/ef2010207. Mendes, A.P.A., Costa, R.C., 2010. Mercado brasileiro de biodiesel e perspectivas futuras. BNDES Setorial, Rio de Janeiro 31, 253–279. Meneghetti, S.M.P., Meneghetti, M.R., Serra, T.M., Barbosa, D.C., Wolf, C.R., 2007. Biodiesel production from vegetable oil mixtures: cottonseed, soybean, and Castor oils. Energy Fuels 21 (6), 3746–3747. https://doi.org/10.1021/ef070039q. Monteiro, M., Ambrozin, A., Liao, L., Ferreira, A., 2008. Critical review on analytical methods for biodiesel characterization. Talanta 77 (2), 593–605. https://doi.org/10. 1016/j.talanta.2008.07.001. Muniyappa, P.R., Brammer, S.C., Noureddini, H., 1996. Improved conversion of plant oils and animal fats into biodiesel and co-product. Bioresour. Technol. 56 (1), 19–24. https://doi.org/10.1016/0960-8524(95)00178-6. Okwundu, O.S., El-Shazly, A.H., Elkady, M., 2019. Comparative effect of reaction time on biodiesel production from low free fatty acid beef tallow: a definition of product yield. SN Appl. Sci. 1 (2). https://doi.org/10.1007/s42452-018-0145-1. Pereira, G.G., Garcia, R.K.A., Ferreira, L.L., Barrera-Arellano, D., 2017. Soybean and soybean/beef-tallow biodiesel: a comparative study on oxidative degradation during long-term storage. J. Am. Oil Chem. Soc. 94 (4), 587–593. https://doi.org/10.1007/ s11746-017-2962-6. Ramos, M.J., Fernández, C.M., Casas, A., Rodríguez, L., Pérez, Á., 2009. Influence of fatty acid composition of raw materials on biodiesel properties. Bioresour. Technol. 100 (1), 261–268. https://doi.org/10.1016/j.biortech.2008.06.039. Serrano, M., Oliveros, R., Sánchez, M., Moraschini, A., Martínez, M., Aracil, J., 2014. Influence of blending vegetable oil methyl esters on biodiesel fuel properties: oxidative stability and cold flow properties. Energy 65, 109–115. https://doi.org/10. 1016/j.energy.2013.11.072. Silva, A.A.L., Dias Santos, A.G., Di Souza, L., Da Silva Caldeira, V.P., Luz Júnior, G.E., Araújo, A.S., 2015. Síntese e Caracterização de Biodiesel de Sebo Bovino e de sua mistura B10. Orbital - Electron. J. Chem. 7 (1). https://doi.org/10.17807/orbital. v7i1.680. Srinivasan, G.R., Shankar, V., Jambulingam, R., 2019. Experimental study on influence of dominant fatty acid esters in engine characteristics of waste beef tallow biodiesel. Energy Explor. Exploit. 37 (3), 1098–1124. https://doi.org/10.1177/ 0144598718821791. Teixeira, L.S.G., Assis, J.C.R., Mendonça, D.R., Santos, I.T.V., Guimarães, P.R.B., Pontes, L.A.M., Teixeira, J.S.R., 2009. Comparison between conventional and ultrasonic preparation of beef tallow biodiesel. Fuel Process. Technol. 90 (9), 1164–1166. https://doi.org/10.1016/j.fuproc.2009.05.008. Teixeira, L.S.G., Couto, M.B., Souza, G.S., Filho, M.A., Assis, J.C.R., Guimarães, P.R.B., Teixeira, J.S.R., 2010. Characterization of beef tallow biodiesel and their mixtures with soybean biodiesel and mineral diesel fuel. Biomass Bioenergy 34 (4), 438–441. https://doi.org/10.1016/j.biombioe.2009.12.007. Viegas, I.M.A., Barradas Filho, A.O., Marques, E.P., Pereira, C.F., Marques, A.L.B., 2018. Oxidative stability of biodiesel by mixture design and a four-component diagram. Fuel 219, 389–398. https://doi.org/10.1016/j.fuel.2018.01.124. Wyatt, V.T., Hess, M.A., Dunn, R.O., Foglia, T.A., Haas, M.J., Marmer, W.N., 2005. Fuel properties and nitrogen oxide emission levels of biodiesel produced from animal fats. J. Am. Oil Chem. Soc. 82 (8), 585–591. https://doi.org/10.1007/s11746-005-1113-2. Yuan, M.-H., Chen, Y.-H., Chen, J.-H., Luo, Y.-M., 2017. Dependence of cold filter plugging point on saturated fatty acid profile of biodiesel blends derived from different feedstocks. Fuel 195, 59–68. https://doi.org/10.1016/j.fuel.2017.01.054.
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