die

S.G

Keywords:Tobacco seed oilBiodieselQualityOxidation stability

valducehe b

antioxidants that are tert-butylhydroquinone, butylated hydroxytoluene, propyl gallate, pyrogallol,

oducel enginoils a

tent, cetane number, water content, acid value, iodine value andheating value of the biodiesel fuel. In addition, the effects of tobaccoseed oilmethyl ester addition to dieselNo. 2 on the performance andemissions of a diesel enginewerepresented in the study. In addition,Veljkovic et al. [8] produced methyl ester from crude tobacco seedoil havinghigh free fatty acids byusing twosteps: the acid-catalyzedesterication followedby the base-catalyzedmethanolysis. Density,

authors best knowledge, unlike tobacco leaves, tobacco seeds gen-erally are not collected from the elds and are not commercialproducts. However, tobacco seed has a potential to become a com-mercial product.

Since the seeds are not collected as a product, there is no statis-tical information about the amount of tobacco seed in the literature.However, it may be estimated from the tobacco plant cultivationareas. The amount of seed that could be collected per hectare areamay change depending on the place, the type of tobacco plantand weather conditions. As an example, the amount of seed per

Corresponding author. Tel.: +90 2582963139; fax: +90 2582963262.

Energy Conversion and Management 52 (2011) 20312039

Contents lists availab

n

lseE-mail addresses: n_usta@pau.edu.tr, usta_n@yahoo.com (N. Usta).table oils for biodiesel production in the world. In addition, thereare many studies carried out in different countries to nd newfeedstocks such as mahua oil [1], castor oil [2], tall oil [3], tea seedoil [4] and microalgae [5] for biodiesel production.

In this connection, tobacco seed oil (TSO) has been considered asa new feedstock for biodiesel production. Giannelos et al. [6] exam-ined some of physical and chemical properties of tobacco seed oiland suggested that tobacco seed oil may be an appropriate substi-tute for diesel fuel. Usta [7] produced biodiesel fuel from tobaccoseed oil and examined ester content, density, viscosity, sulphur con-

tion, the water content and free fatty acid, affecting the yield oftobacco seed oil methyl ester for KOH and NaOH catalysts. Effectsof these variables on kinematic viscosity, ash point, and freezingpoints were investigated.

Tobacco is a well-known plant due to its leaves used to producecigarette and cigar. However, cigarette and cigar are harmful prod-ucts for human beings. Therefore, tobacco plant has a negative con-notation on peoples mind. However, tobacco plant has so manypotentials beyond its cigarette and cigar production. Tobacco planthas huge amount of small seeds other than the leaves. To theIodine numberCold lter plugging point

1. Introduction

Vegetable oils can be used to prrenewable alternative fuels for dieseble oils, rapeseed, soybean and palm0196-8904/$ - see front matter 2010 Elsevier Ltd. Adoi:10.1016/j.enconman.2010.12.021a-tocopherol and butylated hydroxyanisole were used to improve the oxidation stability. Among them,pyrogallol was found to be the most effective antioxidant. The iodine number was improved with blend-ing the biodiesel produced from tobacco seed oil with a biodiesel that contains more saturated fatty acids.However, the blending caused increasing the cold lter plugging point. Therefore, four different cold owimprovers, which are ethylenevinyl acetate copolymer, octadecene-1-maleic anhydride copolymer andtwo commercial cold ow improvers, were used to decrease cold lter plugging point of the biodiesel andthe blends. Among the improvers, the best improver is said to be octadecene-1-maleic anhydride copoly-mer. In addition, effects of temperature on the density and the viscosity of the biodiesel wereinvestigated.

2010 Elsevier Ltd. All rights reserved.

biodiesel fuels that arees. Among the vegeta-re the most-used vege-

kinematic viscosity, caloric value, iodine value, saponicationvalue and acid value of the methyl ester were examined. In anotherstudy related to the biodiesel production from tobacco seeds, Parlaket al. [9] examined some variables such as reaction temperature,alcohol/oil molar ratio, type and amount of catalyst, reaction dura-quality. Among the properties, only oxidation stability and iodine number of the biodiesel, which mainlydepend on fatty acid composition of the oil, were not within the limits of the standard. Six differentProperties and quality verication of bio

N. Usta a,, B. Aydogan a, A.H. on b, E. Uguzdogan c,a Pamukkale University, Mechanical Engineering Department, 20070 Denizli, Turkeyb Pamukkale University, Food Engineering Department, 20070 Denizli, TurkeycPamukkale University, Chemical Engineering Department, 20070 Denizli, Turkey

a r t i c l e i n f o

Article history:Received 9 August 2009Received in revised form 11 May 2010Accepted 13 December 2010

a b s t r a c t

Tobacco seed oil has been ethe biodiesel that was proto bring all properties of t

Energy Conversio

journal homepage: www.ell rights reserved.sel produced from tobacco seed oil

. zkal b

uated as a feedstock for biodiesel production. In this study, all properties ofd from tobacco seed oil were examined and some solutions were derivediodiesel within European Biodiesel Standard EN14214 to verify biodiesel

le at ScienceDirect

and Management

vier .com/ locate /enconman

d Mhectare area is around 600 kg in DenizliTurkey and it was alsodetermined that the amount of seed may increase up to 1200 kgper hectare area in some elds [7]. In addition, in Macedonia, theamount of seed is around 2500 kg per hectare area; also, it wasinformed that the new generated plants could give more thanthis amount of seed [10]. In that case, tobacco plant may be grownfor the seeds other than leaves and it may be a useful plant forhuman beings, not harmful. In this connection, there are someongoing studies to increase the amount of tobacco seed per hectarearea.

The seeds are collected after the leaves collection. Tobacco seedcontains signicant amount of oil (3549% by weight) [7,11].Tobacco seed oil is extracted from tobacco seeds and does not con-tain nicotine [12]. Since tobacco seed oil is not edible oil, it can beused in different applications such as biodiesel production [7]. Inaddition, after the oil is extracted, the remaining part as a cakecan be used for animal food [13]. In this respect, it may be said thattobacco plant is a promising crop and may be a useful plant forhuman beings in near future.

A biodiesel fuel that will be used in diesel engines must meetvarious specications included in biodiesel standards, mainly USBiodiesel Standard ASTM 6751 [14] and European Biodiesel stan-dard EN 14214 [15]. Properties of a biodiesel depend on the rawvegetable oil and the production technique. While some of theseproperties are related to biodiesel production technique, severalproperties like oxidation stability, iodine number, cold lter plug-ging point (CFPP), cetane number, and viscosity directly dependupon the fatty acid composition of the raw oil. Therefore, the fattyacid composition of a vegetable oil is the most important parame-ter inuencing the properties of a vegetable oil and its methyl ester[16]. The fatty acid composition of tobacco seed oil depends on thetype of tobacco plant, place and weather conditions. In general, themain fatty acids of most of the tobacco seed oils extracted from to-bacco seeds grown in Bulgaria [11], Macedonia [13], India, Turkey,England [17], Pakistan [18] and Serbia [19], are linoleic, oleic,palmitic and stearic acids.

The biodiesel production techniques from different kinds of oilsthat are waste rapeseed oil [20], used frying oils, soapstocks, fats,greases [21], jatropha oil, ricebran oil [22,23] were examined inmany studies. In general, it was reported that oils containing highfree fatty acids could not be effectively converted to biodiesel usingonly an alkaline catalyst. It is required to reduce the free fatty acidsof the feedstock using an acid catalyzed pre-treatment to esterifythe free fatty acids before transesterifying the triglycerides withan alkaline catalyst to complete the reaction [24,25]. Demirbas[26] compared different transesterication methods for productionof biodiesel from vegetable oils and fats. In addition, Demirbas [27]also examined biodiesel production via rapid transesterication.

In general, biodiesel fuels are blended with diesel fuel No. 2 andthe blends are used in diesel engines. The amount of biodiesel inthe blends may change depending on the properties of biodiesel,regulations and application places. Most of the automotive compa-nies allow maximum 5% (in volume basis) biodiesel usage in theirdiesel engines. In Europe, the amount of biodiesel addition intodiesel fuel is around 5% (in volume basis) and this value is 20%(in volume basis) in USA. Meanwhile, many studies have been car-ried out to characterize the performance and exhaust emissions ofdiesel engines fuelled with biodiesel fuels produced from differentoils such as soybean oil, yellow grease [28], neem oil [29], soybeanoil [30], used cooking oil [31]. Agarwal [32] and Lapuerta et al. [33]presented reviews including results of many studies.

This study is the extension of previous studies of rst author[7,34]. To the authors best knowledge, an extensive study has

2032 N. Usta et al. / Energy Conversion annot been performed on the quality of biodiesel produced fromtobacco seed oil, yet. This was the basic motivation behind theresearch in this paper. In this study, a comprehensive work wasperformed to produce biodiesel fuel, which could meet the speci-cations of European Biodiesel Standard EN 14214, from tobaccoseed oil. This is an important subject for biodiesel production fromany source. Meanwhile, it is thought that this study will give someguidelines for future researchers who will try to produce biodiesel,which meet the specications of EN 14214 standard, from new oilsources.

2. Materials and methods

2.1. Tobacco seed oil

Since tobacco seed oil is not available in markets, it wasrequired to collect seeds from the elds in Buldan region of Denizliin Turkey. The oil content of the seed was determined by using asoxhlet apparatus on 10 0.001 g of ground tobacco seeds, byusing diethyl ether as a solvent for 8 h. The necessary amount oftobacco seed oil was extracted by using a solvent extraction meth-od that was performed in a special pilot reactor designed and man-ufactured for this study as shown in Fig. 1. Again, diethyl ether wasused as a solvent in the process. The oil extraction process isexplained below.

The collected seeds were dried to remove moisture in 2 h at110 1 C in an oven and ground using a special grinding machine.Then, the dried and ground seeds were put on a shelve in a maintank of the reactor. The diethyl ether was poured onto the seedsas solvent. The seed/diethyl ether ratio was 5 kg/12 L in the reactor.The seeds were left in the diethyl ether for 3 h. Then, the oil anddiethyl ether mixture were allowed to ow in a second tank thatis heated via special heating plates. The diethyl ether was boiledand the vapor was allowed to pass through a heat exchanger thatwas cooled with a circulating water-cooling unit. The diethyl ethercondensed in the heat exchanger was collected in a third tank. Theoil was taken from the bottom of the second tank. The detailedinformation about oil extraction unit and the process was givenin Usta et al. [35].

The fatty acid composition of the oil was determined bygasliquid chromatography in Marmara Research Center ofThe Scientic and Technological Research Council of Turkey(MAM-TUBITAK).

2.2. Biodiesel production and determination of its properties

Free fatty acid content of tobacco seed oil was measured by themethod of AOCS Cd 3a-63 [36]. Since the free fatty acid content ofthe extracted tobacco seed oil was below 0.5%, the oil was con-verted into methyl ester by means of transesterication processthat uses a base catalyst. Methyl alcohol and sodium hydroxidewere used as alcohol and catalyst in the transesterication process,respectively. The optimum values for molar ratio of methyl alcoholto glycerides and the amount of sodium hydroxide were deter-mined as 6/1 and 7.5 0.2 g/kg the oil, respectively [35].

Transesterication process was carried out using a speciallydesigned stainless steel reactor (28 L) which have a heater and amixer as shown in Fig. 2. The biodiesel production process isexplained below. The tobacco seed oil was stirred by a mixer run-ning at 900 5 rpm, meanwhile the oil was heated with the heaterto keep the oil temperature at 55 1 C. Sodium hydroxide wasdissolved in methyl alcohol to produce the sodium methoxide.Then the prepared sodium methoxide was poured into the oil.The mixture was stirred at 900 5 rpm for 2 h holding the temper-ature at 55 1 C. Then, the heater was turned off and stirring wascontinued for 2 h without heating. The mixture was left in the reac-

anagement 52 (2011) 20312039tor and was allowed to form two layers for at least 8 h. The bottomlayer was glycerol while the upper layer was the biodiesel. Afterthe settling was completed, the glycerin was taken out from the

nd M1

8

9

N. Usta et al. / Energy Conversion abottom. The biodiesel was washed with distilled water three times.At the end of the process, the biodiesel was heated over 100 C toremove any water left in the biodiesel. The nal biodiesel becameclear straw yellow.

All properties of tobacco seed oil methyl ester were determinedaccording to EN 14214 standards by Marmara Research Center of

6

4 5

2

10

9

10

13

16

16

Fig. 1. Oil extraction reactor (1. Main tank, 2. Second tank (diethyl ether + oil mixture), 3Manometer and pressure relief valve, 9. Heating plate, 10. Valve, 11. Cooling water inleDiethyl ether, 16. Thermocouple).

1

6

7

3

8

45

2

Fig. 2. Biodiesel reactor (1. Main tank, 2. Heating plate 3. Valve liquid inlet, 4.Electric motor, 5. Control unit, 6. Mixer, 7. Thermocouple, 8. Valve liquid outlet).3

8 810

10 10

11

12

14 15

7

. Third tank (diethyl ether), 4. Shelve, 5. Seed, 6. Diethyl ether, 7. Heat exchanger, 8.t, 12. Cooling water outlet, 13. Control unit, 14. Diethyl ether and oil mixture, 15.anagement 52 (2011) 20312039 2033The Scientic and Technological Research Council of Turkey(MAM-TUBITAK). The information about the accuracy of the mea-surements and the uncertainty of the computed results in determi-nation of these properties were dened in each test method of thestandards given in EN 14214.

In addition, the viscosity measurements at different tempera-tures (045 C) were performed by using an A&D Sine-wave vibroviscometer SV-10 which measures viscosity by detecting the driv-ing electric current necessary to resonate the two sensor plates at aconstant frequency of 30 Hz and amplitude of less than 1 mm. Thesample was poured into a special sample cup that was replaced in aspecial water jacket connected to a cold-water bath. The tempera-tures of samples were adjusted by changing temperature of thewater in the cold-water bath. The viscosity sensor plates and tem-perature sensor of the viscometer was inserted into the samplesand they were measured at the same time. The measurementswere recorded via special software running in a personalcomputer. The viscosities were measured in 1% accuracy and thetemperatures were measured with an accuracy of 0.1 C.

Density measurements were carried out at different tempera-tures (080 C) using a pycnometer that has capacity of 100 mLbeing calibrated with pure water. For weight measurement, ananalytical weighing balance with an accuracy of 1 mg was used.The uncertainty in density values is less than 0.25%.

2.3. Additives

Some additives were used to improve oxidation stability andCFPP of TSOME. Six different antioxidants were used to improvethe oxidation stability. These are tert-butylhydroquinone (SigmaAldrich), butylated hydroxytoluene (Fluka), propyl gallate (Fluka),Pyrogallol (Fluka), a-tocopherol (SigmaAldrich) and butylatedhydroxyanisole (SigmaAldrich).

Four different additives were used to improve CFPP of TSOME.These are ethylenevinyl acetate copolymer (SigmaAldrich),octadecene-1-maleic anhydride copolymer (SigmaAldrich) andtwo commercial cold ow improvers which are represented asCCFI1 and CCFI2.

3. Results and discussions

The oil content of the collected seeds was determined asapproximately 38 2% (in weight basis) using diethyl ether as anextraction solvent. Meanwhile the yield of biodiesel productionfrom tobacco seed oil was achieved as 88 1 wt.% by applying

acceptable yield, because the oil was the virgin oil and containssome matters other than triglycerides. The legends used in thisstudy are D100 for diesel fuel No. 2, TSOME for tobacco seed oilmethyl ester and TSOMExxD (100-xx) for the blend, which consistsof xx percentage (v/v) TSOME with (100-xx) percentage (v/v) D100.

Properties of a biodiesel fuel depend on the fatty acid composi-tion of the raw oil and the biodiesel production process. Thismeans that the fatty acid composition of the raw oil is very impor-tant and may give some idea about the properties of the biodiesel[16]. Therefore, at the beginning of the studies, fatty acid composi-tion of tobacco seed oil used in this study was determined and it isgiven in Table 1. The main fatty acids are linoleic, oleic, palmiticand stearic acids. Similar fatty acid compositions were found inthe literature for tobacco seed oil [18].

The determined properties of TSOME are given in Table 2.Among the properties, two properties were not within the limitsof EN 14214 standard. These are oxidation stability and iodinevalue. The other properties were within the limits.

Oxidation stability is one of the major properties affecting theuse of biodiesel and mainly depends on the fatty acid compositionof the oil. Since tobacco seed oil mainly consists of unsaturatedfatty acids, the lower value for oxidation stability was an expectedproblem. In addition, the biodiesel production techniques mayaffect the oxidation stability. Therefore, the production should beperformed very carefully. The other important point is the storageof the biodiesel. The biodiesel should be stored in suitable condi-tions. Different additives were used to improve the oxidation sta-bilities of biodiesel fuels [37,38]. However, there are someimportant issues. The additive should be compatible with biodieseland should not affect negatively other fuel properties. In this study,six different antioxidants that are tert-butylhydroquinone, butyl-

Table 1Fatty acid composition of the tobacco seed oil.

Fatty acid %

Caprylic 8:0 0.08Capric 10:0 0.00Lauric 12:0 0.00Myristic 14:0 0.12Palmitic 16:0 8.16Palmitoleic 16:1 0.10Stearic 18:0 3.56Oleic 18:1 12.14Linoleic 18:2 72.98Linolenic 18:3 0.76Arachidic 20:0 0.20Eicosenoic 20:1 0.12Behenic 22:0 0.07Erucic 22:1 0.00Others 1.71

2034 N. Usta et al. / Energy Conversion and Management 52 (2011) 20312039Ester content % (m/m)Density at 15 C kg/m3

Viscosity at 40 C mm2/sFlash point CSulphur content mg/kgCarbon residue (on 10% distillation residue) % (m/m)Cetane numberthe procedure mentioned in previous section. This may be

Table 2Properties of TSOME.

Property UnitSulfated ash content % (m/m)Water content mg/kgTotal contamination mg/kgCopper strip corrosion (3 h at 50 C) ratingOxidation stability, 110 C hoursAcid value mg KOH/gIodine value g iodine/100 gLinolenic acid methyl ester % (m/m)Polyunsaturated (P4 double bonds) methyl esters % (m/m)Methanol content % (m/m)Monoglyceride content % (m/m)Diglyceride content % (m/m)Triglyceride content % (m/m)Free glycerol % (m/m)Total glycerol % (m/m)Group I metals (Na + K) mg/kgNaK

Group II metals (Ca + Mg) mg/kgCaMg

Phosphorus content mg/kgCold lter plugging point Cated hydroxytoluene, propyl gallate, pyrogallol, a-tocopherol and

Analysis result EN 14214 Test methodLimits

Min. Max.

98.6 96.5 EN 14103888.5 860 900 EN ISO 121854.23 3.50 5.00 EN ISO 3104165.4 120 EN ISO 36798 10.0 EN ISO 208460.029 0.30 EN ISO 1037051.6 51.0 EN ISO 51650.0004 0.02 ISO 3987354.09 500 EN ISO1293723.95 24 EN 126621A class 1 EN ISO 21600.8 6.0 EN 141120.3 0.50 EN 14104136 120 EN 141110.759 12.0 EN 14103

10

ntra

e

ants

nd Mbutylated hydroxyanisole were added to TSOME in concentrationsbetween 500 ppm and 2000 ppm and the oxidation stabilities weremeasured. The change of oxidation stability with respect to theconcentrations of the antioxidants is shown in Fig. 3. Among theantioxidants, pyrogallol was found to be the most effectiveantioxidant, similar to Tang et al. [39] and Pahgova et al. [40].

0

1

2

3

4

5

6

7

8

9

10

11

12

0 500

Conce

Oxi

datio

n St

abili

ty (h

)

butylated hydroxytoluen

tert-butylhydroquinone

-Tocopherol

Fig. 3. Effects of different antioxid

N. Usta et al. / Energy Conversion aThe addition of pyrogallol at 500 ppm could increase the oxidationstability from 0.8 h to over 6.5 h. It should be noticed that if theoxidation of the original biodiesel was higher than 0.8 h, the smal-ler amount of pyrogallol could increase the oxidation stability over6 h for different biodiesel fuels [35]. It was also determined thatpyrogallol does not affect the CFPP, viscosity, iodine number andcetane number of TSOME negatively.

The iodine value of a biodiesel also directly depends on the fattyacid composition [41]. It cannot be improved with additives.Therefore, the only way is blending original biodiesel with a bio-diesel that has a low iodine value. The biodiesels with low iodinevalue contain more saturated fatty acids, which result in increasingCFPP of the blend. Therefore, the percentage of the biodiesel withlow iodine value should be kept to a minimum in the blends tomeet the limit value 120 g iodine/100 g. Otherwise, the blendingresults in low iodine value, but high CFPP. In this study, a blendT70W30 which included 30% (in weight basis) biodiesel producedfrom waste mixed cooking oil (WMCOME) and 70% (in weight ba-sis) TSOME was prepared to decrease the iodine value just below120 g iodine/100 g. The fatty acid composition of the waste mixedcooking oil is shown in Table 3. As it is seen that the composition isdifferent from that of tobacco seed oil and more saturated. Itsiodine value was 60 g iodine/100 g. Since the waste mixed cookingoil contained high free fatty acids, the biodiesel production tech-nique from the waste mixed cooking oil was different. The detailsof biodiesel production fromwaste mixed cooking oil were given inUsta et al. [35]. The addition of WMCOME increased oxidation sta-bility and the cetane number of the blend. However, the blendingresulted in an increase in CFPP. It should be pointed out thatalthough EN 14214 standard has a restriction on iodine numberof biodiesel; ASTM 6751 standard has no restriction on the iodinenumber. This means that if ASTM 6751 standard is applied in anycountry, there is no need to blend TSOME with any other biodieselto meet the standard.

Cold-ow quality of a fuel is determined by CFPP, cloud pointand pour point. However, CFPP is referred as a cold ow propertyin EN14214 standard. Although the CFPP of TSOME which is

00 1500 2000

tion (ppm)

propyl gallate

pyrogallol

butylated hydroxyanisole

on oxidation stability of TSOME.

anagement 52 (2011) 20312039 20355 C, is acceptable for some weather conditions, the CFPP of theblend T70W30 (70% TSOME and 30%WMCOME in weight basis) in-creased to 0 C. Therefore, four different cold ow improvers,which are ethylenevinyl acetate copolymer, octadecene-1-maleicanhydride copolymer and two commercial cold ow improversrepresented as CCFI1 and CCFI2, were added to TSOME, WMCOMEand the blend T70W30 in concentrations at 0.5% and 1% by weightto decrease CFPP values. The effects of cold ow improvers on CFPPof TSOME, WMCOME and the blend T70W30 are shown in Table 4.Among the improvers, the best improver is said to be octadecene-1-maleic anhydride copolymer. In addition, it was also determinedthat octadecene-1-maleic anhydride copolymer also does not af-fect cetane number and the oxidation stability negatively. It is bet-ter to point out that the commercial improvers CCFI1 and CCFI2 areadvised especially for rapeseed oil methyl ester.

The other properties that are related to the biodiesel productionand purication techniques were within the limits. These proper-ties are ester content, carbon residue, sulphated ash content, watercontent, total contamination, acid value, methanol content, mono-glyceride content, diglyceride content, triglyceride content, freeglycerol and total glycerol. If the process was incomplete and thepurication method was not suitable, there could be someproblems with these properties. This means that there was noany problem with biodiesel production and purication techniqueapplied in this study.

The corrosiveness of a fuel is measured using the copper stripcorrosion test. The copper strip corrosion of TSOME is 1A. It meansthat the corrosiveness of TSOME is fairly low. In addition, as it isexpected from fatty acid composition of tobacco seed oil, linolenicacid methyl ester (0.759% by weight) and polyunsaturated (P4double bonds) methyl esters (0.1% by weight) are within the limits.

Also, the amounts of group I metals (Na + K), group II metals(Ca + Mg) and phosphorus in TSOME are within the limits. In addi-tion, the sulphur content of TSOME is 8 ppm and it is lower than

10 ppm. It is known that some oils may contain higher sulphurcontent. The ash point temperature of TSOME is 165.4 C, whichis higher than the minimum value of the standard (120 C), andthere is no any problem from the safety point of view during trans-portation and storage of TSOME.

In other aspect, the cetane number of TSOME is 51.6, which ishigher than the lower limit of the standard. It is good value, be-cause the cetane number is very important property of the fuelaffecting the ignition delay time that is the time between the startof injection and start of combustion. As the cetane numberdecreases, the ignition delay increases and the main combustionphase decreases. Long ignition delay causes diesel knock.

Viscosity is another important property of biodiesel. Because itaffects the fuel delivery and the atomization of the fuel. Viscosity ofa biodiesel depends on the fatty acid composition of its oil source.The viscosity increases with the chain length and decreases withincreasing the degree of unsaturation [42]. High viscosity causesinadequate operation of the fuel injection system and poor atom-ization of the fuel. The kinematic viscosity of TSOME is4.23 mm2/s at 40 C and is within the limits of the standard.Furthermore, it was thought that it is better to investigate the

Table 3Fatty acid composition of waste mixed cooking oil.

Fatty acid %

Caprylic 8:0 0.05Capric 10:0 0.04Lauric 12:0 0.59Myristic 14:0 1.14Palmitic 16:0 36.16Palmitoleic 16:1 0.21Stearic 18:0 3.18Oleic 18:1 41.92Linoleic 18:2 11.19Linolenic 18:3 0.29Arachidic 20:0 0.42Eicosenoic 20:1 0.21Behenic 22:0 0.09Erucic 22:1 0.02Others 4.49

Table 4Effects of different cold improvers on CFPP of TSOME, WMCOME and their Blend (T70W30-70% TSOME and 30% WMCOME).

Additives Amount of Additive (% in weight basis) CFPP (C)

TSOME WMCOME T70W30

No additive 0.0 5 11 0CCFI1 0.5 5 10 2

1.0 8 11 1CCFI2 0.5 14 7 0

1.0 10 8 2Ethylenevinyl acetate copolymer 0.5 7 7 3

1.0 6 8 0Octadecene-1-maleic anhydride copolymer 0.5 12 6 5

1.0 9 6 2

1920

2036 N. Usta et al. / Energy Conversion and Management 52 (2011) 20312039151617180123456789

1011121314

0 5 10 15 20

Temper

Dyn

amic

Visc

osity

(mPa

s)

TSOME

TSOME75D25

TSOME50D50

D100

TSOME05D95

TSOME

Fig. 4. The dynamic viscosity measurements of TSOME, D100 an25 30 35 40 45

20D80ature (oC)d their blends in the temperature range from 0 C to 45 C.

15

20

25

ity (m

Pa s

)

D100TSOMETSOME with an additive (0.5% - octadecene-1-maleic anhydride copolymer)

0

per

wit

N. Usta et al. / Energy Conversion and Management 52 (2011) 20312039 2037viscosity variation of TSOME and its blends with respect to thetemperature. Because the viscosity of liquids increases rapidly asthe temperature is decreased. The dynamic viscosity measure-ments of TSOME, D100 and their blends in the temperature rangefrom 0 C to 45 C are shown in Fig. 4. The lines show the experi-mental results. It should be pointed out that the measurementswere recorded automatically with a personal computer via specialsoftware, there are huge numbers of measurements in the range,and the markers cannot be shown on the gure. The viscosity ofTSOME rapidly increases below 6 C. However, D100 and theblends do not show this kind of sharp increase. It was determined

0

5

10

Dyn

amic

Visc

os

0 5 10 15 2

Tem

Fig. 5. The change of dynamic viscosities of diesel fuel No. 2, TSOME and TSOMEthat antioxidants do not affect the viscosity, however cold owimprovers affect the change of viscosity. The change of viscosityof TSOME, TSOME with additive octadecene-1-maleic anhydridecopolymer at 0.5% by weight and D100 are shown in Fig. 5.Although octadecene-1-maleic anhydride copolymer increasedslightly the viscosity of TSOME, it prevented the increasing ofviscosity in the low temperatures. The regression equation for vis-cosities of D100, TSOME and TSOME with octadecene-1-maleicanhydride copolymer was derived as

l e ABT CT2

1

where A, B, and C are constants, T is the temperature in K, and l inmPa s. The constants for the fuels are given in Table 5. The R2 valuewas determined as 0.999 for this equation.

Table 5The coefcients of Eq. (1) for Diesel Fuel No. 2, TSOME and TSOME with an additive (octa

Material

D100TSOME (45.06.0 C)TSOME (6.04.0 C)TSOME (0.04.0 C).TSOME with an additive (octadecene-1-maleic anhydride copolymer, 0.5% in weightIn general, densities of biodiesel fuels are higher than that ofD100. The chain length and saturation level of biodiesel fuelsincrease the density. The density of a diesel engine fuel has someeffect on the break up of the fuel injected into the cylinder andmore fuel is injected by mass as the fuel density increases [21].The density of TSOME is 888.5 kg/m3 at 15 C and within the limitsof standards. In addition, the densities of TSOME in the tempera-ture range from 0 C to 80 C were measured and the change ofthe density with respect to the temperature is given in Fig. 6.The regression equation for the density of TSOME was derivedand is given in the following equation:

25 30 35 40 45

ature (oC)h an additive (octadecene-1-maleic anhydride copolymer, 0.5% in weight basis).q 0:70484T 898:15485 2where T is temperature in C, q is the density in kg/m3. The R2 valuewas determined as 0.999 for this equation.

The obtained tobacco seed cake after extraction of oil was char-acterized by high yield of proteins (41% by weight) and crudebers (15% by weight) and low percentage of mineral matters(0.2% by weight) which makes it comparable to seed cakes of otheroil-bearing seeds, and could serve as feed supplement in premixesfor livestock and poultry [13].

4. Conclusions

The biodiesel production and fatty acid composition of the oil isvery important to obtain high quality biodiesel production. Thisstudy explained the methods to produce biodiesel fuel, which

decene-1-maleic anhydride copolymer, 0.5% in weight basis) (045 C).

A B C

0.942688 2366.578 722364.4490.691176 1092.259 530297.792

6162.894 3441491.194 80623515.466108.708 53593.021 6306425.189

basis) 0.409212 1762.149 635774.807

850

40mpe

/m

nsit

d Mmeets EN 14214 standard, from tobacco seed oil. There were noany problems with the properties related to the biodiesel produc-tion technique. In addition, there were no problems with someproperties, like cetane number, density and viscosity, whichdepend on the fatty acid composition of the raw oil. However,the oxidation stability of the biodiesel was lower than theminimum limit of the standard and the iodine number was higherthan the maximum limit of the standard. The oxidation stabilitymay be improved with the use of different antioxidants and pyro-gallol was found to be most effective antioxidant. Iodine numberwas improved with blending with an other biodiesel producedfrom waste cooking oil that has more saturated fatty acids.Although the blending decreased the iodine number of tobacco

830

840

0 10 20 30Te

Fig. 6. The change of TSOME de860

870

Den

sity

(kg

880

890

900

910

3 )

2038 N. Usta et al. / Energy Conversion anseed oil methyl ester below the maximum limit of standard, coldlter plugging point was increased. Therefore, it was required touse cold ow improvers. Octadecene-1-maleic anhydride copoly-mer is an effective cold ow improver for TSOME and its blendswith WMCOME. It was determined that addition of pyrogallol at500 ppm and octadecene-1-maleic anhydride copolymer at 0.5%by weight does not affect the other properties negatively. Althoughaddition of octadecene-1-maleic anhydride copolymer increasedthe viscosity slightly, it improves the viscosity of the biodiesel atlow temperatures.

Acknowledgement

The authors would like to thank The Scientic and TechnologicalResearch Council of Turkey (TUBITAK) for supporting this studyunder Project Contract No. 104M256.

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N. Usta et al. / Energy Conversion and Management 52 (2011) 20312039 2039

Properties and quality verification of biodiesel produced from tobacco seed oilIntroductionMaterials and methodsTobacco seed oilBiodiesel production and determination of its propertiesAdditives

Results and discussionsConclusionsAcknowledgementReferences