Energy Conversion and Management 82 (2014) 169–176

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Energy Conversion and Management

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Properties and use of Moringa oleifera biodiesel and diesel fuel blendsin a multi-cylinder diesel engine

http://dx.doi.org/10.1016/j.enconman.2014.02.0730196-8904/� 2014 Elsevier Ltd. All rights reserved.

⇑ Corresponding authors. Tel./fax: +60 03 79674448 (M. Mofijur). Tel.: +60122314659 (A.E. Atabani).

E-mail addresses: mofijduetme@yahoo.com (M. Mofijur), a_atabani2@msn.com(A.E. Atabani).

M. Mofijur a,⇑, H.H. Masjuki a, M.A. Kalam a, A.E. Atabani a,⇑, M.I. Arbab a, S.F. Cheng b, S.W. Gouk b

a Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysiab Unit of Research on Lipids (URL), Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia

a r t i c l e i n f o a b s t r a c t

Article history:Received 4 September 2013Accepted 24 February 2014Available online 28 March 2014

Keywords:Biodiesel productionCharacterizationBlendingEngine performanceEmissions

Researchers have recently attempted to discover alternative energy sources that are accessible, techni-cally viable, economically feasible, and environmentally acceptable. This study aims to evaluate the phys-ico-chemical properties of Moringa oleifera biodiesel and its 10% and 20% by-volume blends (B10 and B20)in comparison with diesel fuel (B0). The performance and emission of M. oleifera biodiesel and its blendsin a multi-cylinder diesel engine were determined at various speeds and full load conditions. The prop-erties of M. oleifera biodiesel and its blends complied with ASTM D6751 standards. Over the entire rangeof speeds, B10 and B20 fuels reduced brake power and increased brake specific fuel consumption com-pared with B0. In engine emissions, B10 and B20 fuels reduced carbon monoxide emission by 10.60%and 22.93% as well as hydrocarbon emission by 9.21% and 23.68%, but slightly increased nitric oxideemission by 8.46% and 18.56%, respectively, compared with B0. Therefore, M. oleifera is a potential feed-stock for biodiesel production, and its blends B10 and B20 can be used as diesel fuel substitutes.

� 2014 Elsevier Ltd. All rights reserved.

1. Introduction harmful substances; and it produces less harmful emissions to

The reserves of petroleum-derived fuels are diminishing withtheir increasing demand every day. Moreover, the combustionproducts that result from burning these fuels are considered harm-ful to the environment. Several factors such as depletion of petro-leum derived fuel, climate change, and increase in the price ofpetroleum products have generated interest in discovering alterna-tive energy sources among researchers [1–3]. In the last decades,many researchers worldwide have searched for new alternativeenergy sources that are available, technically feasible, economi-cally viable, and environmentally acceptable [4]. Biodiesel is con-sidered one of the best alternative energy sources because of itspotential to reduce dependency on fossil diesel fuel, capacity to de-crease environmental pollutant output, and application in com-pression ignition (CI) engines with no modification [5,6].Biodiesel is nonexplosive, biodegradable, nonflammable, renew-able, nontoxic, environment friendly, and similar to diesel fuel[7,8]. The main advantages of biodiesel include the following: itcan be blended with diesel fuel at any proportion; it can be usedin a CI engine with no modification; it does not contain any

the environment than diesel fuel [9,10].Biodiesel can be obtained through transesterification of vegeta-

ble oils, animal fats, waste cooking oil, and waste restaurantgreases [11]. It originates from edible and nonedible sources. Themost common edible oils of biodiesel include palm oil, rapeseedoil, sunflower oil, coconut oil, and peanut oil, whereas the noned-ible oil sources of biodiesel are Jatropha, neem, cotton, jojoba, rub-ber, Moringa, Mahua, castor, and animal tallow [12,13]. Thepresent study aims to evaluate the potential of biodiesel produc-tion from Moringa oleifera oil as a promising feedstock that is easilyaccessible worldwide. This study characterizes the physico-chem-ical properties of M. oleifera biodiesel and its 10% and 20% by-vol-ume blends. The properties that were investigated includekinematic viscosity, density, flash point, cloud point, pour point,and cold filter plugging point, viscosity index, and oxidation stabil-ity. Then, the performance of the 10% and 20% by-volume blends ofM. oleifera biodiesel was assessed in a diesel engine. The relevantfuel properties of M. oleifera biodiesel, such as engine performanceand emission characteristics, were fully investigated and comparedwith those of diesel fuel.

2. Literature review

M. oleifera is a member of the Moringaceae family, whichmainly grows in tropical countries [14]. This drought-tolerant

Nomenclature

ASTM American Society for Testing and MaterialsBP brake powerB0 diesel fuelB10 10% biodiesel + 90% dieselB20 20% biodiesel + 80% dieselBSFC brake specific fuel consumptionBTE brake thermal efficiencyCMOO crude Moringa oleifera oilCO carbon monoxide

CO2 carbon dioxideFAC fatty acid compositionFT-IR Fourier transform-Infra redHC hydrocarbonNO nitric oxideNOx oxides of nitrogenPM particulate matter

170 M. Mofijur et al. / Energy Conversion and Management 82 (2014) 169–176

pioneer species is locally known in Malaysia as kachang kelur, butcommercially it called ‘‘ben oil’’ or ‘‘behen oil.’’ M. oleifera containsbehenic (docosanoic) acid and significantly prevents oxidative deg-radation. M. oleifera can be used for medicinal and clinical pur-poses, and contains a substantial amount of nutrition value. Thespecies is locally distributed in northwest India, Southeast Asia,Africa, South America, and Arabia [15,16]. However, it is also cur-rently available in the Central America, Philippines, North America,Malaysia, and Cambodia. M. oleifera grows fast, can withstand awide range of rainfall (25 cm to 300+ cm per year), and sustain lifein poor soil (pH 5–9) [17,18]. The height of M. oleifera tree canrange from 5 m to 10 m [19]. The seeds of M. oleifera are triangularand contain approximately 40% of oil by weight. The oil producedfrom the seed kernel of M. oleifera is golden yellow. M. oleifera oilreportedly contains elevated amounts of oleic acid, which com-prises approximately 74.41% of its entire fatty acid profile [20].

Recent studies [21,22] have investigated the potential of biodie-sel production from edible oil and nonedible oil sources, and theirutilization in a diesel engine. Only a few studies [14,16,23–26]have reported on the potential of biodiesel production from M.oleifera, a nonedible oil source, and evaluated the blends of M. oleif-era in a multi-cylinder diesel engine. Only Rajaraman et al. [27]have reported on the performance and emission characteristics ofMoringa oil methyl ester and its blends (B20 to B100) in a directinjection diesel engine at various load conditions. They reportedthat M. oleifera blend exhibits lower brake thermal efficiency(BTE) than diesel fuel because of the former’s lower heating valueand higher viscosity and density than the latter. In engine emis-sions, M. oleifera blend produces lower HC, CO and PM emissionbut NOx emission than diesel fuel. The properties of M. oleifera bio-diesel and its blends meet the ASTM D6751 specifications, whichare the standard specification for biodiesel (B100) fuels and indi-cate the product’s suitability to be used in diesel engines.

3. Materials and methods

3.1. Materials

Crude M. oleifera oil (CMOO) was collected from UniversitySains Malaysia. All other chemicals, reagents, and accessories werepurchased from LGC Scientific Sdn Bhd (Malaysia). The experimen-tal investigation was performed using diesel fuel (B0), B10 (90%diesel and 10% M. oleifera biodiesel), and B20 (20% M. oleifera bio-diesel and 80% diesel).

3.2. Equipment list

Table 1 highlights the equipment used to measure the physico-chemical properties of M. oleifera biodiesel and its blends.

3.3. Biodiesel production

The high acid value of CMOO causes a problem during the sep-aration process. Therefore, a two-step process (acid–base catalyst)was suggested to convert M. oleifera oil into biodiesel (methyl es-ter). The production of biodiesel was conducted at the EnergyLab of University Malaya using a 1 L batch reactor with a refluxcondenser, a magnetic stirrer, a thermometer, and a sampling out-let. The summary of the biodiesel production process is given inTable 2. Furthermore, a comprehensive view of the biodiesel pro-duction processes is furnished in the following section.

3.3.1. Acid-catalyzed processFor biodiesel production, an acid-catalyzed process was used

before transesterification to reduce the high acid value of crudeoils. In this process, a molar ratio of 12:1 methanol to CMOO and1% (v/v oil) of sulfuric acid (H2SO4) were added to the preheatedoil at 60 �C for 3 h at 600 rpm stirring speed. After the reaction,the product was transferred to a separating funnel to separatethe esterified oil (lower layer) from the upper layer, which includesexcess alcohol, sulfuric acid, and impurities. The lower layer wasthen loaded into a control rotary evaporator (IKA) and heated at60 �C under vacuum conditions for 1 h to remove methanol andwater from the esterified oil. After esterification, the acid valuewas reduced to less than 4.

3.3.2. Alkaline-catalyzed processIn the alkaline-catalyzed process, a molar ratio of 6:1 of meth-

anol and 1% (w/w oil) of potassium hydroxide (KOH) were addedto the preheated esterified M. oleifera oil at 60 �C for 2 h at600 rpm stirring speed. After the reaction, the produced methyl es-ter was deposited in a separation funnel for 16 h to separate glyc-erol from methyl ester. The lower layer, which contains glyceroland impurities, was drained.

3.3.3. Post-treatment processThe methyl ester was washed with warm distilled water to re-

move the impurities and glycerol. In this process, 50% (v/v oil) ofdistilled water at 60 �C was sprayed over the surface of the esterand stirred gently. This washing process was repeated severaltimes until the pH of the biodiesel became neutral. The lower layerwas discarded, and the upper layer was poured into a control ro-tary evaporator (IKA) to remove water and excess methanol frommethyl ester. The methyl ester was poured into a flask, dried usinganhydrous sodium sulfate (Na2SO4), and then further dried usingthe control rotary evaporator. Finally, the produced biodiesel wasfiltered using a qualitative filter paper (150 mm diameter, No. 1)to obtain the final product. The percentage of yield of the producedbiodiesel was more than 90%.

Table 1Summary of the equipment used to measure the properties of M. oleifera biodiesel and its blend.

Property Equipment Test method Accuracy

Kinematic viscosity SVM 3000 (Anton Paar, UK) ASTM D445 0.1%Flash point Pensky-martens flash point – automatic NPM 440 (Normalab, France) ASTM D93 ±0.1 �COxidation stability 873 Rancimat (Metrohm, Switzerland) EN ISO 14112 ±0.01 hCloud and pour point Cloud and pour point tester – automatic NTE 450 (Normalab, France) ASTM D2500 ±0.1 �C

ASTM D97Cold filter plugging point Cold filter plugging point tester – automatic NTL 450 (Normalab, France) ASTM D6371 ±0.1 �CDensity DM 40 (Mettler Toledo, USA) ASTM D1298 ±0.1 kg/m3

Calorific value C2000 basic calorimeter (IKA, UK) ASTM D240 ±0.001 MJ/kgAcid value Automation titration rondo 20 (Mettler Toledo, Switzerland) ASTM D664 ±0.001 mgKOH/g

Table 2Summary of biodiesel production process from M. oleifera oil.

S/n Process parameter Process specification

01 Process selected Acid–base catalyst process02 Reaction temperature 60 �C03 Catalyst used 98% Pure sulfuric acid (1% v/v) and 99%

pure potassium hydroxides (1% w/w)04 Alcohol used Methanol05 Molar ratio 12:1 For esterification and 6:1 for

transesterification06 Reaction time 3 h For esterification and 2 h

for transesterification07 Setting time 15 h08 Stirring speed 600 rpm

M. Mofijur et al. / Energy Conversion and Management 82 (2014) 169–176 171

3.4. Fatty acid composition (FAC)

The FAC of M. oleifera biodiesel was analyzed using gas chroma-tography (Shidmadzu, Japan) equipped with a flame ionizationdetector. Moreover, the results of FAC of M. oleifera biodiesel areshown in Table 3.

3.5. Properties analysis

The physico-chemical properties of the produced biodiesel werecharacterized according to the ASTM D6751 standard. Cetane num-ber (CN), iodine value (IV), and saponification value (SV) weredetermined using the following equations:

CN ¼ 46:3þ ð5458=SVÞ � ð0:225 � IVÞ ð1Þ

SV ¼ Rð560 � AiÞ=MWi ð2Þ

Table 3Fatty acid composition of M. oleifera biodiesel.

Sl. no. Fatty acid (as methyl ester) Molecular weight Shorthand design

1 Lauric 200 12:02 Myristic 228 14:03 Palmitic 256 16:04 Palmitoleic 254 16.15 Stearic 284 18:06 Oleic 282 18:17 Linoleic 280 18:28 Linolenic 278 18:39 Arachidic 312 20:010 Eicosanoic 310 20:111 Behenic 340 22:012 Other

Saturated

Monounsaturated

Polyunsaturated

Total

a Data obtained from Ref. [16].

IV ¼ Rð254 � Ai � DÞ=MWi ð3Þ

where Ai is the percentage of each component, D is the number ofdouble bond, and MWi is the molecular mass of each component.

M. oleifera biodiesel was also characterized by FT-IR using a Per-kin Elmer biodiesel FAME analyzer equipped with an MIR TGSdetector in the range of 4000–400 cm�1 and processed with thecomputer software program spectrum. The resolution was 4 cm�1

and 8 scans.

3.6. Blending of biodiesel

The test fuel was blended with diesel using a homogenizer de-vice at a speed of 2000 rpm. The homogenizer was fixed with aclamp on a vertical stand, which allows for changing the homoge-nizer’s height. To mix the fuels by using the homogenizer, the plugwas turned on and the appropriate speed was selected by using theselector located at the top of the homogenizer.

3.7. Engine tests

The test engine used was a Mitsubishi Pajero (model 4D56T)multi-cylinder diesel engine. The test rig of the engine is shownin Fig. 1. The detailed specifications of the engine are shown in Ta-ble 4. Before running the engine with the biodiesel-blended fuels,the engine was first operated with diesel fuel for a few minutesto warm up the engine. Diesel fuel was also used before engineshutdown. The same procedure was maintained for each fuel. Toperform engine performance and emission tests, the engine wasrun at various speeds (1000–4000 rpm) at full load conditions.The engine test conditions were monitored by a REO-DCA control-ler connected through a desktop to the engine test bed (Fig. 1). ABOSCH exhaust gas analyzer (model BEA-350) was used to mea-

ation Systematic name Formula MOME MOMEa

Dodecanoic C12H24O2 0 0Tetradecanoic C14H28O2 0.1 0Hexadecanoic C16H32O2 7.9 6.5Hexadec-9-enoic C16H30O2 1.7 0Octadecanoic C18H36O2 5.5 6.0Cis-9-Octadecenoic C18H34O2 74.1 72.2Cis-9-cis-12 Octadecadienoic C18H32O2 4.1 1.0Cis-9-cis-12 C18H30O2 0.2 0Eicosanoic C20H40O2 2.3 4.0Cis-11-eicosenoic C20H38O2 1.3 2.0Docosanoic C22H44O2 2.8 7.1

0 1

18.6 23.6

77.1 74.2

4.3 1

100 99.8

172 M. Mofijur et al. / Energy Conversion and Management 82 (2014) 169–176

sure the NO, HC, and CO contents of the exhaust emission gases.The details of gas analyser are shown in Table 5. All tests were rep-licated three times, and the average was obtained.

3.8. Error analysis

Errors and uncertainties in the experiments can arise frominstrument selection, condition, calibration, environment, observa-tion, reading, and test planning. Uncertainty analysis was requiredto prove the accuracy of the experiments. The accuracy of thespeed, fuel measurement, brake power (BP), and time was±10 rpm, ±1% of the reading, ±0.07 kW, and ±0.1 s respectively.The relative uncertainty of brake-specific fuel consumption (BSFC)was determined using the linearized approximation method ofuncertainty. Table 6 shows the summary of the values of measure-ment accuracy and the relative uncertainty of various parameters,including BP, BSFC, CO, HC, and NO emission.

4. Results and discussion

4.1. Characterization of M. oleifera biodiesel and blends

To characterize pure M. oleifera biodiesel (B100), several proper-ties such as density, flash point, viscosity, viscosity index, calorificvalue, cloud and pour points, and oxidation stability were exam-ined and compared based on ASTM D6751 standards. Table 7shows the detailed physico-chemical characteristics of M. oleiferabiodiesel (B100) and its blends (B10 and B20). All the physico-chemical properties of M. oleifera biodiesel were found to meetthe ASTM D6751 standards. Thus, M. oleifera biodiesel can be usedin a diesel engine as diesel fuel substitutes. Moreover, Table 7emphasizes that one of the main features of M. oleifera biodieselis its high oxidation stability (26.2 h). This result agrees with[16], which indicated that M. oleifera possesses significant resis-tance to oxidative degradation.

4.2. Engine performance

In this study, engine performance in terms of BP and BSFC wasevaluated. The influence of M. oleifera biodiesel on engine perfor-mance depends on the relationship between the fuel injection sys-tem and the fuel properties, oxygenation nature of the biodiesel,

Fig. 1. Engine tes

higher viscosity, and lower calorific value. These effects have a ma-jor influence on spray formation and combustion. The followingsection discusses the obtained results of these parameters. Table 8shows the results of statistical analysis for the test fuel at full loadconditions.

4.2.1. BPFig. 2 shows the trend line of the engine BP output of M. oleifera

biodiesel at different engine speeds. The BP increased steadily asthe engine speed increased up to 3500 rpm and then decreased be-cause of high frictional force. Over the entire range of speed, theaverage BP values were 28.72, 27.51, and 26.41 kW for fuel sam-ples B0, B10, and B20, respectively. The biodiesel blend fuels pro-duced lower BP than diesel fuel. In addition, biodiesel blend fuelsB10 and B20 decreased the BP by 4.22% and 8.03% compared withdiesel fuel. The decrease in BP can be attributed to the biodieselblends’ lower calorific values and higher viscosities than diesel fuel(Table 7). These properties of the biodiesel blends influenced thecombustion system. The prolonged ignition delays due to theblends resulted in incomplete combustion because of their higherviscosity compared with diesel fuel. Uneven combustion character-istic of biodiesel fuel reduces the engine BP [28,29].

4.2.1. BSFCThe different BSFC values of diesel and biodiesel blend fuels

with their trend line are shown in Fig. 3. The BSFC values werehigher when biodiesel blend fuel was used. This result is supportedby previous findings [30–32]. Compared with diesel fuel, the BSFCslightly increased with increasing biodiesel blend ratio. The BSFC ofdiesel engine depends on the relationship among volumetric fuelinjection system, fuel density, viscosity, and lower heating value[33]. Over the entire range of speed, the average BP values were386, 406 and 418 g/kW h for fuel samples B0, B10, and B20, respec-tively. The biodiesel blend fuels consumed a higher amount of fuelto produce a unit kW of power than diesel fuel. In addition, biodie-sel blend fuel samples B10 and B20 increased the BSFC by 5.13%and 8.39%, respectively, compared with diesel fuel. The higher BSFCof biodiesels can be attributed to the effects of the lower heatingvalue (Table 7) of the blends [28]. Biodiesel fuel is delivered intothe engine on a volumetric basis per stroke; thus, larger quantitiesof biodiesel are fed into the engine.

t bed set-up.

Table 4Details specification of the engine.

Engine model 4D56T (Mitsubishi Pajero)Engine type 4 Cylinder inlineDisplacement L 2.5Cylinder bore � stroke mm2 91.1 � 95Compression ratio 21:1Maximum engine speed rpm 4200Maximum power kW 78Fuel system Distribution type jet pump (indirect injection)Lubrication system Pressure feedCombustion chamber Swirl typeCooling system Radiator cooling

Table 5Details of the exhaust gas analyzer.

Equipment Method Measurement Upperlimit

Accuracy

BOSCH gasanalyser

Non-dispersiveinfrared

CO 10.00 vol% ±0.001 vol%

Non-dispersiveinfrared

CO2 18.00 vol% ±0.01 vol%

Flame ionizationdetector (FID)

HC 9999 ppm ±l ppm

Electro-chemicaltransmitter

NO 5000 ppm ±1 ppm

Table 6Summary of measurements uncertainty.

Measurements Accuracy Relative uncertainty

BP ±0.07 kW ±0.243BSFC ±5 g/kW h ±0.013CO ±0.001 vol% ±0.003NO ±1 ppm ±0.005HC ±1 ppm ±0.090CO2 ±0.01 vol% ±0.001

M. Mofijur et al. / Energy Conversion and Management 82 (2014) 169–176 173

Therefore, to produce the same power, more biodiesel fuel isneeded because biodiesel has a lower calorific value comparedwith diesel fuel [34].

4.2.2. BTEThe trend line of engine BTE of M. oleifera biodiesel at different

engine speeds is shown in Fig. 4. With increasing engine speed, theBTE of the Moringa biodiesel blends increased together with diesel.However, the brake thermal efficiency of the Moringa biodieselblends was lower than that of diesel fuel throughout the entirerange. The possible reasons for this reduction are the lower

Table 7Physico-chemical characteristics of M. oleifera biodiesel and its blends.

Properties Units Standards B0

Kinematic viscosity at 40 �C mm2/s ASTM D445 3.23Viscosity index – – 90Density kg/m3 ASTM D1298 827.2Flash point �C ASTM D93 68.5Cloud point �C ASTM D2500 8Pour point �C ASTM D97 0Cold filter plugging point �C ASTM D6371 5Calorific value MJ/kg ASTM D240 45.30Iodine value g I/100 g EN 14111 –Saponification value – – –Oxidation stability h EN ISO 14112 –Cetane number – ASTM D613 48Acid value mg KOH/g ASTM D664 –Total glycerol – ASTM D6584 –

a Data collected from Ref. [16].

calorific value and increased fuel consumption of Moringa biodie-sel blends as compared with diesel fuel.

4.3. Emission analysis

4.3.1. CO emissionCO is produced though incomplete combustion of fuels without

any oxygen molecules, such as petroleum fuels. Several factorssuch as air–fuel ratio, engine speed, injection timing, injectionpressure, and type of fuels affect CO emission [35]. The differentCO emission values of diesel and biodiesel blend fuel with theirtrend line are shown in Fig. 5. Over the entire speed range, fuelsamples B10 and B20 reduced CO emission by 10.60% and 22.93%compared with B0 fuel, respectively. This result agrees with previ-ous reports [27,36–38]. This result can be attributed to the higheroxygen content and higher cetane number of the biodiesel fuelthan diesel fuel. Biodiesel fuel contains 12% higher oxygen thandiesel fuel [14]. As the percentage of biodiesel increased in theblend, the higher oxygen content in biodiesel allows more carbonmolecules to burn and facilitates the completion of combustion.Thus, CO emission can be reduced by using the biodiesel blendsin a diesel engine.

4.3.2. HC emissionUnburned HC results from the incomplete combustion of fuel

and flame quenching [28]. The different HC emission values of die-sel and biodiesel blend fuels with their trend line are shown inFig. 6. The unburned HC emissions for B10 and B20 were lowerthan that for diesel fuel. Over the entire range of speed, B10 andB20 reduced HC emission by 9.21% and 23.68%, respectively. Inaddition, HC emission reduced as the percentage of biodiesel frac-tion in the blends increased. This result can be attributed to thehigh oxygen contents of biodiesel fuel. Biodiesel contains higheroxygen and lower carbon and hydrogen than diesel fuel, all of

B10 B20 B100 MOMEa ASTM D6751

3.54 3.67 5.05 4.83 1.9–6101.1 111.6 184.6 – –830.6 833.6 859.6 – –79.5 82.5 150.5 – 130 min7 8 19 183 6 19 176 6 18 –44.74 43.30 40.05 – –– – 77.5 –– – 199 – –– – 26.2 3.61 3– – 56.30 67.07 47 min– – 0.22 – 0.80– – 0.11 – 0.24% Mass

Table 8Statistical analysis of the test fuel at full load.

BP (Fig. 2) BSFC (Fig. 3) BTE (Fig. 4) CO (Fig. 5) HC (Fig. 6) NO (Fig. 7)

B0 B10 B20 B0 B10 B20 B0 B10 B20 B0 B10 B20 B0 B10 B20 B0 B10 B20

Mean 28.72 27.51 26.42 386 405.51 418.09 20.93 20.16 19.72 0.37 0.33 0.29 10.86 9.86 8.29 210.86 228.71 250Median 32.49 31.45 29.96 380 406 401 20.91 20.93 20.47 0.31 0.26 0.23 10 9 7 229 250 264Std 8.82 8.3 7.99 54.56 53.27 55.83 2.77 2.64 2.53 0.16 0.16 0.17 3.72 3.18 3.45 50.06 49.15 52.64

8

13

18

23

28

33

38

500 1000 1500 2000 2500 3000 3500 4000

Bra

ke p

ower

[K

W]

Engine speed [rpm]

B0

B20

B10

Fig. 2. Variation of brake power with respect to the speed at full load condition.

300

350

400

450

500

550

600

500 1000 1500 2000 2500 3000 3500 4000

BSF

C [

g/K

w.h

]

Engine speed [rpm]

B10

B20

B0

Fig. 3. Variation of brake specific fuel consumption with respect to the speed at fullload condition.

5

10

15

20

25

500 1000 1500 2000 2500 3000 3500 4000

BT

E (

%)

Engine speed [rpm]

B0

B10

B20

Fig. 4. Variation of brake thermal efficiency with respect to the speed at full loadcondition.

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

500 1000 1500 2000 2500 3000 3500 4000C

O [

vol %

]Engine speed [rpm]

B10

B20

B0

Fig. 5. Variation of CO emissions with respect to the speed at full load condition.

0

2

4

6

8

10

12

14

16

18

20

500 1000 1500 2000 2500 3000 3500 4000

HC

[pp

m]

Engine speed [rpm]

B10

B20

B0

Fig. 6. Variation of HC emissions with respect to the speed at full load condition.

174 M. Mofijur et al. / Energy Conversion and Management 82 (2014) 169–176

which trigger an improved and complete combustion process[39,40].

4.3.3. NO emissionThe different NO emission values of diesel and biodiesel blend

fuel with their trend line are shown in Fig. 7. The NO values werehigher when biodiesel blend fuel was used. Similar findings werereported in previous studies [41]. B10 and B20 emitted 8.46% and18.56% higher NO than diesel fuel over the entire speed range. Thisresult can be attributed to the lean air/fuel ratio. Biodiesel is anoxygenated fuel and contains 12% more oxygen in its molecularstructure, which causes higher chamber temperature by improvingcombustion at its warmed-up condition [42]. Thus, NO emission isincreased with the use of the biodiesel blend compared with dieselfuel. Moreover, increased NO can be explained in terms of adiabaticflame temperature. Biodiesel fuel contains higher percentages ofunsaturated fatty acids that have higher adiabatic flame tempera-ture, which causes higher NO emission [41].

100

125

150

175

200

225

250

275

300

500 1000 1500 2000 2500 3000 3500 4000

NO

[ p

pm]

Engine speed [rpm]

B10

B20

B0

Fig. 7. Variation of NO emissions with respect to the speed at full load condition.

M. Mofijur et al. / Energy Conversion and Management 82 (2014) 169–176 175

5. Conclusions

Biodiesel is one of the best alternative sources of fuel because ofits potential to reduce dependency on fossil diesel fuel, capacity todecrease environmental pollutant output, and application in CI en-gines without further modification. This study aims to produce bio-diesel from CMOO and to evaluate its 10% and 20% by-volumeblends in a diesel engine. The following conclusions were drawnfrom the experiments. After esterification process acid value re-duced significantly and after transesterification process the per-centage of yield was found more than 90%. The properties of M.oleifera biodiesel and its blends conform to ASTM D6751 standards.Over the entire speed range, B10 and B20 yielded an averagereduction of BP compared with diesel fuel. Meanwhile, the averageBSFC of B10 and B20 was slightly higher than that of diesel fuel.B10 and B20 reduced CO emission and slightly increased NO emis-sion than diesel fuel. Therefore, M. oleifera is a potential feedstockfor biodiesel production, and B10 and B20 blends can be used as di-rect diesel fuel substitutes.

Acknowledgment

The authors would like to acknowledge University of Malaya forfinancial support through High Impact Research Grant UM.C/HIR/MOHE/ENG/07.

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