Energy Fuels 2010, 24, 1996–2001 Published on Web 02/16/2010
: DOI:10.1021/ef901131m
)
Blends of Biodiesels Synthesized from Non-edible and Edible Oils: Effects on the Cold Filter Plugging Point Amit Sarin,*,† Rajneesh Arora,‡ N. P. Singh,‡ Rakesh Sarin,§ R. K. Malhotra,§ and Shruti Sarin
† Department of Applied Sciences, Amritsar College of Engineering and Technology, Amritsar 143001, India, Punjab Technical University, Jalandhar 144011, India, §Research and Development Centre, Indian Oil Corporation Limited, Sector 13, Faridabad 121007, India, and Institute of Chartered Accountants of India (ICAI), Amritsar 143001, India )
‡
Received October 5, 2009. Revised Manuscript Received January 6, 2010
To minimize use of biodiesels synthesized from edible oils, such as palm oil, because of the raising food versus fuel issue, palm biodiesel (PBD) was blended in different weight ratios with biodiesels synthesized from tree-borne non-edible oil seeds, jatropha and pongamia, to examine the effects on the cold filter plugging point (CFPP) of PBD. The CFPP of PBD improved significantly after blending with jatropha biodiesel (JBD) and pongamia biodiesel (PoBD). The dependence of CFPP upon the esters of fatty acid composition was also examined. Good correlations between the CFPP and palmitic acid methyl ester (PAME) were obtained. A correlation between CFPP and total unsaturated fatty acid methyl ester (X) was also determined. Using these two correlations, the CFPP of different biodiesel blends can be determined.
In south Asian countries, such as India, biodiesel can be harvested and sourced from non-edible seed oils, such as jatropha and pongamia. Jatropha curcas and Pongamia pinnata are two such trees, which can grow on any type of soil, need minimum input and management, have low moisture demand, start giving seeds after 3 and 5 years of plantation, respectively, have 25-30% oil content, and have a productive life of more than 40 years.12 In fact, implementation of biodiesel through non-edible oil seeds will lead to many advantages, such as providing green cover to wasteland, supporting agricultural and rural economies, reducing the dependency upon imported crude oil, and reducing air pollution.13 Therefore, the sustainable production of vegetable oils for biodiesel production from tree crops, such as J. curcas and P. pinnata, which can be cultivated on marginal land, has the potential to not only provide a renewable energy resource but also alleviate the competitive situation that exists as a result of the food versus fuel issue. Although biodiesel is environmentally compatible, it has certain limitations. The low-temperature flow properties of biodiesel are characterized by the cloud point (CP), pour point (PP), and cold filter plugging point (CFPP), and these must be considered when operating compression-ignition engines in a moderate temperature climate during winter months. “CP” is the temperature at which a sample of the fuel starts to appear cloudy, indicating that wax crystals have begun to form, which can clog fuel lines and filters in the fuel system of a vehicle. “PP” is the temperature below which the fuel will not flow. “CFPP” is the temperature at which fuel causes a filter to plug as a result of its crystallization.14-16
1. Introduction Biodiesel is defined as monoalkyl ester derivatives of longchain fatty acids, commercially produced through the transesterification of vegetable oils, used frying oils or animal fats with alcohol and alkaline catalysts. Researchers have investigated different biodiesel production techniques and biodiesel properties and concluded that these vegetable-oil-based fuels can be used as alternative fuels.1-8 Edible oils, such as soybean, sunflower, and rapeseed oils, are common feedstocks used for biodiesel production in the U.S.A. and Europe. Southeast Asian countries, such as Malaysia, Indonesia, and Thailand, have surplus palm crops. However, the majority of Asian countries are net importers of edible oils; therefore, these oils cannot be used for the production of biodiesel. Moreover, the production of biofuel from edible oils has raised serious concerns on the preservation of the food security of the planet.9,10 It is estimated that, even if all of the edible oils are used for biodiesel production, even then they will not be sufficient for meeting fuel demand11 and it will also lead to inflationary pressures in the vegetable oil market, which was recently being witnessed. To reduce the dependency upon edible oils for the production of biodiesel, there is need to find alternate feedstocks. *To whom correspondence should be addressed. Telephone: þ91183-5069538. Fax: þ91-183-5069535. E-mail:
[email protected]. (1) Ali, Y.; Hanna, M. A. Bioresour. Technol. 1994, 50, 153–163. (2) Chien, Y.-C.; Lu, M.; Chai, M.; Boreo, F. J. Energy Fuels 2009, 23, 202–206. (3) Qian, J.; Yun, Z. Energy Fuels 2009, 23, 507–512. (4) Ma, F.; Hanna, M. A. Bioresour. Technol. 1999, 70, 1–15. (5) May, C. Y.; Liang, Y. C.; Foon, C. S.; Ngan, M. A.; Hook, C. C.; Basiron, Y. Fuel 2005, 84, 1717–1720. (6) Berchmans, H. J.; Hirata, S. Bioresour. Technol. 2008, 99, 1716– 1721. (7) Karmee, S. K.; Chadha, A. Bioresour. Technol. 2005, 96, 1425– 1429. (8) Yuan, H.; Yang, B. L.; Zhu, G. L. Energy Fuels 2009, 23, 548–552. (9) Gui, M. M.; Lee, K. T.; Bhatia, S. Energy 2008, 33, 1646–1653. (10) Srinivasan, S. Renewable Energy 2009, 34, 950–954. (11) Chisti, Y. Biotechnol. Adv. 2007, 25, 294–306. r 2010 American Chemical Society
(12) Kumar, R.; Sharma, M.; Ray, S. S.; Sarpal, A. S.; Gupta, A. A.; Tuli, D. K.; Sarin, R.; Verma, R. P.; Raje, N. R. SAE Tech. Pap. 200428-0087, 2004. (13) Malhotra, R. K.; Sarin, R. SAE Tech. Pap. 2004-28-030, 2004. (14) Dunn, R.; Bagby, M. O. J. Am. Oil Chem. Soc. 1995, 72, 895–904. (15) Dunn, R. O.; Shockley, M. W.; Bagby, M. O. J. Am. Oil Chem. Soc. 1996, 73, 1719–1728. (16) Imahara, H.; Minami, E.; Saka, S. Fuel 2006, 85, 1666–1670.
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Energy Fuels 2010, 24, 1996–2001
: DOI:10.1021/ef901131m
Sarin et al.
Joshi and Pegg studied the flow properties of biodiesel fuel blends at low temperatures.17 Chiu et al. have studied the impact of cold flow improvers on a soybean biodiesel blend.18 Kleinova et al. discussed the cold flow properties of fatty esters.19 Baptista et al. predicted the multivariate nearinfrared spectroscopy models for CFPP.20 Sarin et al. studied the effect of blends of palm-jatropha-pongamia biodiesel blends on CP and PP and concluded that CP and PP of palm biodiesel (PBD) improved significantly after blending with jatropha biodiesel (JBD) and pongamia biodiesel (PoBD).21 Sarin et al. synthesized the surrogate molecules, i.e., methyl, ethyl, isopropyl, and butyl esters of β-branched fatty acid, having substantially better oxidation stability (OS), low-temperature flow properties, and cetane number.22 The CFPP for biodiesel blends is the measurement used within the biodiesel industry globally to provide a good indicator of the lowest operability temperature for diesel engines; therefore, it is an important criterion for biodiesel.23 From the above-mentioned literature reports, it can be concluded that it will not be possible to use biodiesel as fuel having a high CFPP. Few researchers have investigated the blending effect of biodiesels synthesized from edible oils on CFPP,24,25 but none of the reports determined the blending effects of biodiesels synthesized from non-edible and edible oils on CFPP. Properties of various individual fatty esters that comprise biodiesel determine the overall fuel properties of biodiesel fuel, and in turn, the properties of various fatty esters are determined by the structural features of the fatty acid that comprise a fatty ester.26,27 Blending of biodiesel with different fatty acid methyl ester (FAME) compositions is therefore expected to improve the CFPP. Therefore, when PBD and JBD are blended, the blended biodiesel will have a lower CFPP than PBD. Therefore, the first objective of this study was to examine and improve the CFPP of PBD by blending it with JBD and PoBD to minimize the use of edible palm oil. The second objective was to study the effect of the FAME compositions in the blended biodiesels on CFPP and determine correlation between them.
transesterification process, involving the reaction of oil with methanol under reflux conditions.28,29 A series of experiments are used to determine the optimal reaction conditions to obtain maximum conversion. Methanol (8:1 M ratio to oil) is added to the reactor followed by the slow addition of the catalyst (0.6 wt % oil) with stirring. The stirring is continued until the complete dissolution of the catalyst (15 min). To the stirred solution, oil is added and the reaction temperature was set at 65 °C for the experiment. After completion of the reaction, the material is transferred to a separating funnel and both phases are separated. The upper phase is methyl ester (biodiesel), and the lower phase is glycerin. Alcohol from both phases is distilled off under vacuum. The glycerin phase is neutralized with acid and stored as crude glycerin. Methyl ester is washed with the water twice to remove the traces of glycerin, unreacted catalyst, and soap formed during the transesterification. The residual product is kept under vacuum to remove the residual moisture. PBD, JBD, and PoBD samples were tested for physicochemical properties as per American standard test method ASTM D-6751, EN 14214 standard, and Indian standard IS 15607 (Table 1).21,25,28-31 FAME compositions of biodiesel samples were determined by gas chromatography on a gas chromatograph (GC; PerkinElmer, Clarus 500, New Delhi, India, located at the R&D Centre, Indian Oil Corporation Ltd, Faridabad, India), using nitrogen as a carrier gas and di(ethylene glycol) succinate (DEGS) column by preparing the corresponding fatty acid esters and comparing them to standard fatty acid ester samples. GC was equipped with a flame ionization detector (FID) and a glass column (3.1 m 2.1 mm inner diameter) with a temperature program of 150-250 °C (6 °C/min and hold for 20 min). The oven temperature was kept at 200 °C, and the injector temperatures were 230 and 250 °C, respectively. Detailed FAME composition of three biodiesels is given in Table 2.21 A total of 21 blends of PBD, JBD, and PoBD were prepared in different weight ratios (%), and their detailed FAME composition is shown in Table 3.21 CFPP was measured according to ASTM D-6751 test method, ASTM D-6371; EN 14214 test method, EN 116; and IS 15607 test method, IS 1448 P:10, using the CFPP apparatus (Widsons, Delhi, India).21,25,30,31 The sample was cooled in a glass tube under prescribed conditions and inspected at intervals of 1 °C. The temperature at which ester structures crystallized was recorded as the CFPP. Data for CFPP and total FAME composition for all biodiesel samples were imported into SPSS for Windows version 16.0 software [Lovely Professional University (LPU), Jalandhar, India] for statistical regression analysis. Data for all analytical measurements are means of triplicate. Subsequent analysis showed no stastically significant difference among the measurements.
2. Experimental Section 2.1. Materials and Methods. PBD, JBD, and PoBD samples used in the present work were kindly supplied by the R&D Centre, Indian Oil Corporation Ltd., Faridabad, India, and used as received. Otherwise, biodiesel is mainly prepared by the (17) Joshi, R. M.; Pegg, M. J. Fuel 2007, 86, 143–151. (18) Chiu, C. W.; Schumacher, L. G.; Suppes, G. J. Biomass Bioenergy 2004, 27, 485–491. (19) Kleinova, A.; Paligova, J.; Vrbova, M.; Mikulec, J.; Cvengros, J. Process Saf. Environ. Prot. 2007, 85, 390–395. (20) Baptista, P.; Felizado, P.; Menezes, J. C.; Correia, M. J. N. Talanta 2008, 77, 144–151. (21) Sarin, A.; Arora, R.; Singh, N. P.; Sarin, R.; Malhotra, R. K.; Kundu, K. Energy 2009, 34, 2016–2021. (22) Sarin, R.; Kumar, R.; Srivastav, B.; Puri, S. K.; Tuli, D. K.; Malhotra, R. K.; Kumar, A. Bioresour. Technol. 2009, 100, 3022–3028. (23) Gerpen, J. V. http://www.crimsonrenewable.com/UofIdaho. php, 2008. (24) Park., J.-Y.; Kim, D.-K.; Lee, J.-P.; Park, S.-C.; Kim, Y.-J.; Lee, J.-S. Bioresour. Technol. 2008, 99, 1196–1203. (25) Moser, B. R. Energy Fuels 2008, 22, 4301–4306. (26) Knothe, G. Fuel Process. Technol. 2005, 86, 1059–1070. (27) Knothe, G. Energy Fuels 2008, 22, 1358–1364. (28) Sarin, A.; Arora, R.; Singh, N. P.; Sharma, M.; Malhotra, R. K. Energy 2009, 34, 1271–1275. (29) Sarin, A.; Arora, R.; Singh, N. P.; Sarin, R.; Sharma, M.; Malhotra, R. K. J. Am. Oil Chem. Soc. 2009, doi: 10.1007/s11746-0091530-0.
3. Results and Discussion 3.1. Analysis of Biodiesel Samples. It is clear from Table 1 that PBD meets all of the specifications. JBD and PoBD also meet all of the specifications, except the induction period of 6 h because of the high content of unsaturated FAMEs. The results were very much in line with the previous works performed on biodiesel properties, which indicated that the majority of samples failed in the EN 14112 test.21,24-26,28,29 PBD, JBD, and PoBD had CFPP values of 14, 1, and -2 °C, respectively. Therefore, the order of CFPP was PBD > JBD > PoBD. (30) Burton, R. An overview of ASTM D6751: Biodiesel standards and testing methods. Alternative Fuels Consortium, Jan 2008. (31) American Society for Testing and Materials (ASTM). Standard test method for cold filter plugging point of diesel and heating fuels, ASTM D6375-05. In ASTM Annual Book of Standards; American Society for Testing and Materials: West Conshohocken, PA, 2005.
1997
-2 1 14
0.01 0.015 90% 2.54 0.01 0.02 90% 3.95 0.01 0.015 90% 9.24
JBD (wt %)
PoBD (wt %)
PBD (wt %)
14.2 1.4 6.9 43.1 34.4 21.1 78.9
9.8
40.3
6.2 72.2 11.8 16.0 84.0
4.1 43.4 12.2 44.4 55.6
variable
IS 1448 P:10
FAME compositions of the three biodiesel samples given in Table 2 clearly indicate the predominance of saturated FAMEs in PBD. JBD mainly consisted of esters of oleic and linoleic acids. PoBD contained mainly esters of oleic acid. Contents of saturated FAMEs for PBD, JBD, and PoBD were 44.4, 21.1, and 16.0%, respectively, and contents of unsaturated FAMEs for the three biodiesels were 55.6, 78.9, and 84.0%, respectively. 3.2. CFPP Study. 3.2.1. Blending of Two Biodiesels. PBD and JBD were blended in weight percent 100:00 (PBD), 80:20 (PJBD-1), 60:40 (PJBD-2), 40:60 (PJBD-3), 20:80 (PJBD-4), and 00:100 (JBD). Figure 1 shows that the CFPP of PBD improved significantly when JBD is blended with varying weight ratios. When PBD was blended with PoBD in weight percent 100:00 (PBD), 80:20 (PPoBD-1), 60:40 (PPoBD-2), 40:60 (PPoBD-3), 20:80 (PPoBD-4), and 00:100 (PoBD), CFPP of blended PBD dropped to below 1 °C when PoBD became more than 60 wt % (Figure 2). It was found that the effect of all blends of PoBD in PBD was relatively more than the blends of JBD in PBD in improving the CFPP of PBD. Although pure PBD having a high CFPP could not be used in the winter season, blending with JBD and PoBD of low CFPP remarkably improved the CFPP of PBD, and therefore, the use of edible palm oil can be minimized. These results are very much comparable to the previous work performed on the effect of blends of PJBD and PPoBD on other low-temperature flow properties, CP and PP.21 These results are also in agreement with previous reports, which indicated that the CFPP of PBD could be improved through blending with rapeseed biodiesel, soybean biodiesel, canola biodiesel, and sunflower biodiesel.24,25 JBD and PoBD were blended in weight percent 100:00 (JBD), 80:20 (JPoBD-1), 60:40 (JPoBD-2), 40:60 (JPoBD-3), 20:80 (JPoBD-4), and 00:100 (PoBD). Figure 3 shows that the CFPP of JBD is improved when PoBD is blended in it. These results are comparable to the previous work performed on the effect of blends of JPoBD on CP and PP.21 3.2.2. Blending of Three Biodiesels. PBD, JBD, and PoBD were blended in weight percent 60:20:20 (PJPoBD-1), 40:40:20 (PJPoBD-2), 40:20:40 (PJPoBD-3), 20:60:20 (PJPoBD-4), 20:40:40 (PJPoBD-5), and 20:20:60 (PJPoBD6). Blending PBD with JBD and PoBD of low CFPP remarkably improved the CFPP of PBD (Figure 4). These results are also very much comparable to the previous work performed on the effect of blends of PJPoBD on CP and PP.21 Therefore, blending PBD synthesized from edible oil with JBD and PoBD separately and with both JBD and PoBD remarkably improved the CFPP of PBD; therefore, its use can be minimized and, in addition, will alleviate the competitive situation that exists as a result of the food versus fuel issue. 3.3. Dependence of CFPP on Methyl Esters of Fatty Acid Compositions. FAME compositions of 21 biodiesel blends of PBD, JBD, and PoBD are given in Table 3.21 A good
EN 116
EN ISO 14112
D-6371
maximum of 0.02 maximum of 0.24 maximum of 0.001 90% at 360 °C minimum of 3 h D-6584 D-6584 D-4951 D-1160 EN 14112
EN ISO 14105/14106 EN ISO 14105 EN 14107
maximum of 0.02 D-6584 maximum of 0.25 D-6584 maximum of 0.0010 D-4951 not under specifications minimum of 6 h EN 14112
maximum of 0.02 maximum of 0.25 maximum of 0.001 minimum of 90% minimum of 6 h
0.42 0.48 0.26 maximum of 0.50 IS 1448 P:1/Sec.1 maximum of 0.5 maximum of 0.50 D-664
maximum of 0.3 EN ISO 10370
EN ISO 14104
1 57.4 0.05 0.037 1 55.3 0.01 0.032 maximum of 1 minimum of 51 maximum of 0.05 maximum of 0.05 IS 1448 P:15 IS 1448 P:9 D-2709 D-4530 maximum of 1 minimum of 51
D-130 D-613 D-2709 D-4530
copper corrosion cetane number water and sediment (vol %) conradson carbon residue (CCR) 100% (% mass) neutralization value (mg of KOH/g) free glycerin (% mass) total glycerin (% mass) phosphorus (% mass) distillation temperature oxidation stability at 110 °C (h) CFPP (°C)
EN ISO 2160 EN ISO 5165
IS 1448 P:21 IS 1448 P:25 IS 1448 P:4 ASTM D 5453 minimum of 120 3.5-5.0 maximum of 0.02 maximum of 0.0010 EN ISO 3679 EN ISO 3104 EN ISO 3987 EN ISO 20846/20884
minimum of 130 1.9-6.0 maximum of 0.02 maximum of 0.0015 (S 15) maximum 0.05 (S 500) maximum of 3 minimum of 47 maximum of 0.05 maximum of 0.05 D-93 D-445 D-874 D-5453/D-4294 flash point (°C) viscosity at 40 °C (cSt) sulphated ash (% mass) sulfur (% mass)
ASTM D-6751 test method
ASTM D-6751 limits
EN 14214 test method
EN 14214 limits
IS 15607 test method
JBD
palmitic (C16:0) palmitolic (C 16:1) stearic (C18:0) oleic (C18:1) linoleic (C18:2) saturated unsaturated
163 4.30 0.002 0.004
PBD
138 4.50 0.002 0.003
Table 2. FAME Composition of Biodiesel Samples21
IS 15607 limits
1 55.27 0.03 0.036
Sarin et al.
minimum of 120 2.5-6.0 maximum of 0.02 maximum of 0.005
PoBD
: DOI:10.1021/ef901131m FAME
property (units)
Table 1. Physicochemical Properties of PBD, JBD, and PoBD According to ASTM D-6751, EN 14214, and IS 15607 Standards21,25,28-31
142 4.23 0.002 0.0043
Energy Fuels 2010, 24, 1996–2001
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Energy Fuels 2010, 24, 1996–2001
: DOI:10.1021/ef901131m
Sarin et al.
Table 3. FAME Compositions of 21 Blended Biodiesel Samples21 blending ratio of PBD/JBD/ PoBD (wt %) 100:00:00 80:20:00 80:00:20 60:40:00 60:20:20 60:00:40 40:60:00 40:40:20 40:20:40 40:00:60 20:80:00 20:60:20 20:40:40 20:20:60 20:00:80 00:100:00 00:80:20 00:60:40 00:40:60 00:20:80 00:00:100
palmitic acid methyl ester (wt %)
stearic acid methyl ester (wt %)
40.3 35.1 34.4 29.8 28.9 28.1 24.6 23.8 22.9 22.0 19.5 18.6 17.6 16.8 15.9 14.2 13.3 12.5 11.5 10.7 9.8
4.1 4.7 4.4 5.2 5.1 4.9 5.8 5.6 5.5 5.4 6.3 6.2 6.1 5.9 5.8 6.9 6.8 6.6 6.5 6.3 6.2
palmitolic acid methyl oleic acid methyl ester linoleic acid methyl ester (wt %) (wt %) ester (wt %) 0.3 0.6 0.3 0.8 0.6 0.3 1.1 0.8 0.6 0.3 1.4 1.1 0.8 0.6 0.3
43.4 43.3 49.1 43.3 49.1 54.9 43.2 49.0 54.9 60.7 43.2 49.0 54.8 60.6 66.4 43.1 48.9 54.7 60.6 66.4 72.2
12.2 16.6 12.1 21.1 16.6 12.1 25.6 21.0 16.4 11.9 29.9 25.4 20.9 16.4 11.9 34.4 29.9 25.4 20.8 16.3 11.8
Figure 1. CFPP of PBD blended with JBD.
Figure 2. CFPP of PBD blended with PoBD.
correlation was obtained from Figure 5 between CFPP and contents of palmitic acid methyl ester (PAME) (wt %) of three biodiesel blends as follows: CFPP ¼ 0:511ðPAMEÞ -7:823 ð0 < PAME < 45Þ ð1Þ
These results are in agreement with a previous report, which indicated that the CFPP values are highly correlated with the contents of PAME.24 Because the PAME is the dominant component of the saturated FAME in biodiesel blends, a similar correlation of CFPP could be found in the saturated FAME (results not shown). A good correlation could not be found for the variation of CFPP with the contents of oleic acid methyl ester (OAME) of biodiesel blends (results not shown). Similarly, a good
For this equation, the coefficient of correlation (R) was 0.929, the coefficient of determination (R2) was 0.863, and the standard error of estimate (σest) was 1.831. These correlations are highly comparable to the previous results found for the variation of CP and PP with the contents of PAME.21 1999
Energy Fuels 2010, 24, 1996–2001
: DOI:10.1021/ef901131m
Sarin et al.
Figure 3. CFPP of JBD blended with PoBD.
Figure 4. CFPP of PBD blended with JBD and PoBD.
Figure 5. CFPP of blended biodiesels with the contents of PAME.
Figure 6. CFPP of blended biodiesels with the contents of X.
correlation could not be found for the variation of CFPP with the contents of linoleic acid methyl ester (LAME) (results not shown). These results showed that, with regard to the effects of the individual unsaturated FAME, good correlations could not be found. These results are in agreement with previous reports, which indicated that the lowtemperature flow properties are not correlated with the contents of OAME and LAME.21,24 However, when the effect of the contents of total unsaturated fatty acid methyl ester (X) composition on the CFPP was determined, a good correlation was obtained from
Figure 6 between CFPP and X of the three biodiesel blends as follows: CFPP ¼ -0:561ðXÞ þ 43:967 ð0 < Xe84Þ ð2Þ For this equation, R = 0.934, R2 = 0.872, and σest = 1.762. These correlations are also highly comparable to the previous results found for the variation of low-temperature flow properties with the contents of X, respectively.21 These results are also in agreement with a previous report, which indicated that the CFPP values are highly correlated with the contents of X.24 2000
Energy Fuels 2010, 24, 1996–2001
: DOI:10.1021/ef901131m
Sarin et al.
Therefore, when the compositions of blended biodiesels are known, the CFPP can be predicted using eqs 1 and 2. For example, when the weight ratio of PBD, JBD, and PoBD is 40:40:20, the content of PAME is 23.8 wt % and CFPP determined from eq 1 is 4.34 °C, which is close to the experimentally determined value of 5 °C (Figure 5). Minimum and maximum errors of prediction in CFPP calculated from eq 1 are 0.14 and 3.76, respectively. Similarly, CFPP from eq 2 is 4.36 °C for biodiesel blends of weight ratios 40:40:20, when X is 70.6 wt %. Minimum and maximum errors of prediction in CFPP calculated from eq 2 are 0.34 and 3.6, respectively. Therefore, using eqs 1 and 2, it is possible to directly predict the CFPP of biodiesel blends from the contents of PAME as well as from the contents of X.
4. Conclusions PBD, JBD, and PoBD used in this work had CFPP values of 14, 1, and -2 °C, respectively. Blending of PBD with JBD and PoBD significantly improved the CFPP of PBD. CFPP of the blended biodiesels had a close relationship with the FAME composition. When the PAME and X compositions of biodiesel blends are determined, the CFPP can be easily predicted from correlations 1 and 2, respectively. Therefore, to improve the poor CFPP, blending of biodiesels over two is a simple but effective method and can also minimize the use of edible oils having a high CFPP. With the help of correlations, the CFPP of biodiesels produced from new resources can be easily estimated.
2001
