pp oil paper

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Experimental Investigation of thePerformance of Pistachia Palestine Oil asa Diesel FuelM. Al-Hassan a & M. Q. Al-Odat b ca Department of Mechanical Engineering, Faculty of EngineeringTechnology, Al-Balqa' Applied University, Amman, Jordanb Yanbu Industrial College, Department of Mechanical EngineeringTechnology, Yanbu Al Sinaiyah, Saudi Arabiac Department of Mechanical Engineering, Al-Huson UniversityCollege, Al-Balqa' Applied University, Irbid, Jordan

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Energy Sources, Part A, 33:1760–1769, 2011

Copyright © Taylor & Francis Group, LLC

ISSN: 1556-7036 print/1556-7230 online

DOI: 10.1080/15567030903551182

Experimental Investigation of the Performance of

Pistachia Palestine Oil as a Diesel Fuel

M. AL-HASSAN1 and M. Q. AL-ODAT2;3

1Department of Mechanical Engineering, Faculty of Engineering Technology,

Al-Balqa’ Applied University, Amman, Jordan2Yanbu Industrial College, Department of Mechanical Engineering Technology,

Yanbu Al Sinaiyah, Saudi Arabia3Department of Mechanical Engineering, Al-Huson University College,

Al-Balqa’ Applied University, Irbid, Jordan

Abstract In this study, Pistachia Palestine oil was tested to determine its thermo-

physical properties and combustion performance. The ultimate analysis of this oilwas conducted using a high pressure gas chromatography (model 2010). Moreover,

the Pistachia Palestine oil was blended with diesel fuel at a ratio of 5, 10, and 15(v/v%) and the fuel blends were tested in the Hilton combustion laboratory unit C

491 according to standard methods. Based on the fatty acid analyses, the elementalcomposition of the Pistachia Palestine was found to consist (wt%) of 76.4 carbon,

12.3 hydrogen, and 11.3 oxygen. Accordingly, the average chemical formula is C17:44

H33:4 O1:94. Compared with diesel fuel, Pistachia Palestine oil has a higher molecular

weight, viscosity, density, pour point, and cloud point; whereas it has a lower energycontent and stoichiometric air-fuel ratio. In addition, it was found that the stack

temperature and the thermal efficiency of the combustion unit decrease when the fuel

blends were being tested.

Keywords alternative fuel, combustion performance, fuel blends, ultimate analysis,vegetable oil

1. Introduction

The world’s high degree of dependency on energy has led to a large-scale effort in the

search for alternative energy sources. Petroleum fuels as energy sources are expected

to have a limited and restricted life, so alternative resources such as nuclear, hydraulic,

geothermal, wind, and biomass are gradually replacing these sources.

Biomass is considered as one of the most promising renewable future energy sources

due to its large potential, economic viability and various social and environmental ben-

efits. Additionally, it is the fourth largest source of energy in the world, which provides

approximately 14% of the world’s energy needs (Scurlock et al., 1993).

The term biomass covers purpose-grown agricultural crops (e.g., oil seeds), conven-

tional agricultural crops (sugar and starch), and trees. It also covers agricultural forests,

agro, industrial and domestic wastes and residues.

A further method of extracting energy from biomass is the production of vegetable

oils as a fuel. There are many crops grown in rural areas of the world, which are

Address correspondence to Dr. Mohammed Al-Odat, Yanbu Industrial College, Department ofMechanical Engineering Technology, P.O. Box 30436, Yanbu Al Sinaiyah, Saudi Arabia. E-mail:m_alodat@ yahoo.com

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Pistachia Palestine Oil as Diesel Fuel 1761

suitable for oil production: coconut, groundnut, palm, soybean, sunflower, safflower, corn,

rapeseed, sesame, cottonseed, and more.

Vegetable oils are considered as a major alternative biomass source of fuel. The

advantages of vegetable oils as fuel are their heat content, portability, ready availability,

and the fact that they are renewable sources. However, a major obstacle deterring their

use in the heating systems is their high viscosities which are about 10 to 20 times greater

than that of conventional diesel fuel. High viscosities cause poor atomization of the fuel,

incomplete combustion, and ultimately results in operational problems (Peterson, 1986).

For many years, the ready availability of inexpensive petroleum distillate fuels

provided little incentive for experimenting with alternative renewable fuels for heating

systems. However, because of the first worldwide energy crises in 1973, the studies

done on this subject increased. The utilization possibilities of pure or mixed uses of

various refined vegetable oils, used vegetable oils, crude, or oil recovered from residues

and wastes of chemical operations have been tested as a diesel fuel alternative by

numerous researchers (Coombos, 1992; Elliot, 1990; Raymond and Larvor, 1986; White

and Plaskett, 1981). Additionally, the Southwest Research Institute (Reid et al., 1989)

evaluated the chemical and physical properties of 14 vegetable oils. These injection

studies pointed out that the oils behave very differently from petroleum-based fuels.

Bettis et al. (1982) evaluated sunflower, safflower, and rapeseed oils as possible sources

for liquid fuels. The vegetable oils were found to contain 94 to 95% of the energy

content of diesel fuel, and to be approximately 15 times more viscous. Goering et al.

(1981) studied the characteristic properties of eleven vegetable oils to determine the best

suited oil for use as an alternative fuel source. Of the eleven oils tested, corn, rapeseed,

sesame, cottonseed, and soybean oils had the most favorable fuel properties.

At present the use of vegetable oils as alternative diesel fuel was found to be

successful in application in many countries, such as France, Germany, Italy, Austria,

Spain, Sweden, Czech Republic, and the United States of America.

Pistachia Palestine oil (PP oil) is one of the vegetable oils that can be considered

as a new fuel alternative for boilers. However, its utilization for this purpose has not

reported yet in the literature.

The potentials of PP oil as an alternative fuel for diesel engine were investigated in a

previous study (Al-Hasan, 2000). The engine performance characteristics obtained with

the fuel blends did not differ greatly from that of pure diesel fuel. The total evaluations

of the results suggested that 20% by volume of PP oil blended in diesel fuel could be

used as a diesel fuel alternative.

The objectives of this study were to investigate the thermo-chemical properties of PP

oil in terms of chemical composition, heating value, air-fuel ratio, cloud point, and pour

point. Moreover, PP oil-diesel fuel blends were tested in a diesel-fired combustion unit

(similar to residential diesel-fired boiler). Experimental tests were conducted at different

operating conditions in order to identify potential benefits in combustion performance

while noting any combustion problems caused by using PP oil as a diesel fuel replacement

in small-scale residential heating applications. The measured experimental parameters

were the inlet and outlet water temperatures, water flow rate, air and fuel mass flow

rates, and stack temperature.

2. Experimental Apparatus and Procedures

In this experimental study, diesel fuel and PP oil were used. The diesel fuel was obtained

from a commercial gas station in Jordan, and the PP oil was extracted from the PP fruit.

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1762 M. Al-Hassan and M. Q. Al-Odat

The process of oil extraction was carried out in the same way as the extraction of edible

oil from plants. The fuel blends were prepared by making 5, 10, and 15% (v/v) mixes

of PP oil in diesel fuel. Experiments were performed on two stages: (1) determination

of the thermo-chemical properties of PP oil and (2) the determination of the combustion

performance of both PP oil-diesel fuel blends and reference diesel fuel.

2.1. Thermo-chemical Properties

These properties usually depend on both chemical composition and types of bonds found

in the oil. For this reason, the ultimate analysis was performed on PP oil to determine the

elemental composition according to the standard method of fat analysis (Coks and Van,

1966). The fatty acid (FA) composition of PP oil was determined using high pressure gas

chromatography (GC) model 2010 equipped with a split injector (AOC-20i; Shimadzu

Scientific Instruments, Kyoto, Japan), a flame ionization detector, and a DB-23 (60 m

length, 0.25 mm I.D., 0.15 �m film thickness) column (Agilent Technologies, Tokyo,

Japan) with maximum temperature of 260ıC. The operational conditions for GC were as

follows: the starting temperature was 165ıC and this temperature was retained for 8 min;

then the temperature was increased to 185ıC with a rate of 1ıC/min. The temperature

then increased and maintained at 220ıC at a rate of 5ıC/min for a time period of 10

min. The injector and detector temperatures were set at 230ıC and 240ıC, respectively,

and helium was used as a carrier gas at a flow rate of 1.20 mL/min. The FA composition

was reported as a relative percentage of the total peak area. Each FA determination was

run in triplicate, and average values were reported (Table 1).

Flow property of fuels can be characterized by cloud and pour points. The cloud

point is important for ensuring a good performance in cold temperatures. It is defined

as the temperature at which small solid crystals are first visually observed as the fuel

is cooled. The pour point is the temperature at which the fuel is a non-flowing gel and

Table 1

PP oil ultimate analysis

Fatty acid

Molecular mass,

(kg kmol�1)

Percent contribution of

element, %

Trivial name Symbol %, by weight Fatty acid Contribution C H O

Myristic C14H28O2 C14:0 0.06 228.377 0.137 73.630 12.359 14.011

Palmitic C16H32O2 C16:0 26.82 256.431 68.775 74.943 12.579 12.479

Palmitoleic C16H30O2 C16:1 3.57 254.415 9.083 75.536 11.886 12.577

Heptadecanoic C17H34O2 C17:0 0.06 270.458 0.162 75.497 12.672 11.831

Heptadecenoic C17H32O2 C17:1 0.095 268.442 0.255 76.064 12.016 11.920

Stearic C18H36O2 C18:0 1.53 284.485 4.353 75.996 12.756 11.248

Oleic C18H34O2 C18:1 47.76 282.469 134.907 76.539 12.133 11.328

Linoleic C18H32O2 C18:2 19.07 280.453 53.482 77.089 11.501 11.410

Linolenic C18H30O2 C18:3 0.71 278.437 1.977 77.647 10.861 11.492

Arachidic C20H40O2 C20:0 0.12 312.539 0.375 76.861 12.901 10.238

Gadoleic C20H38O2 C20:1 0.125 310.523 0.388 77.360 12.335 10.305

Erucic C22H42O2 C22:0 0.03 338.577 0.102 78.045 12.504 9.451

Lignoceric C24H48O2 C24:0 0.05 368.647 0.184 78.195 13.125 8.680

Sum 100.00 — 274.180a 76.416a 11.305a 12.279a

aAverage value.

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contains so many agglomerated crystals. The cloud (CP) and pour points (PP) of PP oil

were measured according to ASTM D2500 and ASTM D97, respectively.

2.2. Combustion Test

The Hilton combustion laboratory unit C 491 was used to conduct this experimental work.

The schematic diagram of the unit is shown in Figure 1. The unit mainly consists of a

combustion chamber and is attached to the unit auxiliary devices which are necessary for

supplying and measuring the combustion air, cooling water, and fuels. The combustion

chamber is a double shell stainless steel tube with an internal diameter of 46 cm and a

length of 91 cm. Water jackets with space of 25 mm on the cylinder and 38 mm on the

end plate were added to cool the combustion chamber. The combustion air was supplied

through a regulator using a three-stage centrifugal blower. The regulator maintains a gage

pressure of approximately 250 mm H2O at the burner. An orifice plate and a differential

manometer with direct reading scales, calibrated from 0 to 160 kg h�1 were used to

measure the mass airflow rate. Cooling water was supplied to the water jackets from

an overhead tank through a glass tube Rotameter with direct reading scale from 0 to

1,600 kg h�1. Three thermometers were used to measure the inlet air temperature at the

blower outlet pipe, the water temperatures at entry to test rig and the water temperature

at exit of end plate. The fuel was supplied from an overhead tank with a height of about

2.5 m above the combustion unit and the fuel mass flow rate was measured by a glass

Figure 1. Schematic diagram of the Hilton combustion unit. 1—water cooled combustion chamber;

2—refractory quarl; 3—three stage blower fan; 4—rotameters; 5—water input; 6—stack; 7—

thermocouple; 8—thermometers; 9—oil pressure regulator; 10—air flow control; 11—gas input;

12—gravity fuel tank; 13—observation window.

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tube Rotameter with direct reading scale from 0 to 13 kg h�1. A coated chromel-alumel

thermocouple measured the stack temperature through the stack inlet.

The ignition procedures were conducted according to the instruction manual and

steady conditions were established on gaseous fuel (LPG). Then the fuel was changed

over to the tested fuel. The unit was operated at a constant fuel flow with varying air

flow rate to obtain different air- fuel ratios (i.e., different runs). At each air-fuel ratio,

the steady conditions were allowed to be reached and then the readings were taken for

the water mass flow rate (mw), inlet (Tin), and outlet (Tout ) water temperatures, air inlet

temperature, air (ma), and fuel (mf ) mass flow rates and stack temperature (Tst ). The

water mass flow rate was adjusted and kept constant for each run. Each reading was

repeated three times and the result was the average of three readings.

3. Result and Discussions

3.1. PP Oil Chemical Composition

The PP oil chemical composition is determined using the ultimate analysis.The ultimate

analysis was performed to determine the fatty acid compositions and accordingly, to

calculate its elemental composition. Fatty acids, which are found in PP oil and its weight

percent content, are listed in Table 1. As shown in the table, fatty acids vary in their

carbon chain length and in the number of double bonds. Fatty acid chains from PP oil

are 14 to 24 carbons long with zero to three double bonds. The chains without double

bonds are said to be saturated (palmitic acid, stearic acid, arachidic acid, lignoceric acid,

myristic acid, heptadecanoic acid, and erucic acid) and those with a single double bond

are monounsaturated (palmitoleic acid, heptadecenoic acid, gadoleic acid, and oleic acid),

and with two and three double bonds are polyunsaturated (linoleic acid and linolenic

acid). According to Harrington (1986) the high proportions of saturated (28.7%) and

monounsaturated (51.55%) fatty acids in PP oil are considered optimal from a fuel

quality standpoint, because the polymerization during the combustion of the derived fuel

from this oil would be less than that would occur with polyunsaturated fatty acid-derived

fuel.

Based on the fatty acids analyses, shown in Table 1, the elemental composition of

the PP oil was found to consist of 76.4 wt% carbon, 12.3 wt% hydrogen, and 11.3 wt%

oxygen. Moreover, the calculated average chemical formula is C17:44 H33:4 O1:94.

3.2. PP Oil Physical Properties

Knowing the elemental composition of the fuels used for the experiment, the stoichio-

metric air-fuel ratio and the lower heating value of the fuels can be determined as shown

in Appendix A. The computation values of stoichiometric air-fuel ratio and lower heating

value of PP oil, diesel fuel, and its mixtures are presented in Tables 2 and 3.

In order to provide a broader view of PP oil, a comparison of its thermo-physical

properties with diesel fuel and the most common fatty acids occurring in vegetable oils

(others are present in small amounts) was conducted (see Table 4). As shown in the

table, the lower heating value and the stoichiometric AFR of PP oil are approximately

13.8 and 10% respectively, less than that of diesel fuel on a mass basis. This might be

attributed to the elemental composition of fuel (i.e., quantities of C and H), and these

portions of PP oil are lower compared to diesel fuel. This factor causes lower LHV of PP

oil because C and H are the energy sources. In addition, the data in Table 4 indicate that

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Table 2

Fuels lower heating value calculation, kJ � kg�1

Percent contribution

of element

Lower heating

valueFatty acids

and diesel fuel

%, by

weight C H O Fatty acid Contribution

Myristic 0.06 73.630 12.359 14.011 36,244.84 21.75

Palmitic 26.82 74.943 12.579 12.479 37,085.27 9,946.27

Palmitoleic 3.57 75.536 11.886 12.577 36,563.02 1,305.30

Heptadecanoic 0.06 75.497 12.672 11.831 37,440.10 22.46

Heptadecenoic 0.095 76.064 12.016 11.920 36,947.81 35.10

Stearic 1.53 75.996 12.756 11.248 37,759.94 577.73

Oleic 47.76 76.539 12.133 11.328 37,294.38 17,811.79

Linoleic 19.07 77.089 11.501 11.410 36,822.12 7,021.98

Linolenic 0.71 77.647 10.861 11.492 36,343.02 258.04

Arachidic 0.12 76.861 12.901 10.238 38,313.49 45.98

Gadoleic 0.125 77.360 12.335 10.305 37,893.58 47.37

Erucic 0.03 78.045 12.504 9.451 38,393.49 11.52

Lignoceric 0.05 78.195 13.125 8.680 39,167.85 19.58

Sum (PP oil LHV) 37,124.86

Diesel fuel, C12:35H21:76 87.12 12.88 — — 42,823

the oxygen content in the PP oil is about 11.3% by weight, and this would be enhancing

the combustion process and reducing the emission of harmful substances. The density of

PP oil is higher by about 9.68%, and its viscosity, cloud point, and pour point are 10, 5,

and 4 times, respectively, higher than that of diesel fuel.

In addition, as shown in Table 4, the differences between oils from different sources

relate to the weight percent contents of fatty acids in the oil. It can be seen from this

table that PP oil has higher saturated fatty acids (palmitic and stearic) than that of olive

(OV), soybean (SB), canola (CN), and sunflower (SF) oils and lower than that of palm

(PM) oil. Its unsaturated fatty acids (oleic, linoleic, and linolenic) are lower than that

of olive, soybean, sunflower, and canola oils and higher than palm oil. According to

Table 3

Composition properties of fuel mixtures

Fuel mixture, v%

Diesel

fuel PP oil

Stoichiometric

AFR, kg kg�1

Lower heating

value, kJ kg�1

100 0 14.44 42,823

95 5 14.34 42,498

90 10 14.23 42,178

85 15 14.13 41,860

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Table 4

Technical property of diesel fuel and vegetable oils

Vegetable oils

Fuel properties DF PP OVb PMb SBc CNd SFb

Specific gravity,a 15ıC 0.82 0.906 0.912 0.918 0.9150 0.92 0.921

Viscosity,a 40ıC (cSt) 4.10 40.0 46.5 42.00 41.2 37.0 34.2

Cloud point, ıC 2.0 10.0 N.A N.A �3.9 �3.9 7.2

Pour point, ıC �9 3 N.A 6 �12.2 �31.7 �12.2

Total sulfur (w%) 1.0 0.011 N.A N.A N.A N.A N.A

AFR Stoichiometric (kg/kg) 14.4 12.55 N.A N.A N.A N.A N.A

Lower heating value (MJ kg�1) 42.8 37.12 N.A 38.0 37.9 36.9 36.8

Fatty acid composition (w%)

Palmitic acid, C16:0 — 26.82 13.21 32–46 10.6 4–5 6.38

Stearic acid, C18:0 — 1.53 3.11 4–6 4.28 1–2 4.59

Palmitoleic acid, C16:1 — 3.57 N.A N.A N.A N.A N.A

Oleic acid, C18:1 — 47.76 73.6 37–53 29.69 55–63 19.05

Linoleic acid, C18:2 — 19.07 9.26 6–12 52.34 20–31 69.98

Linolenic acid, C18:3 — 0.71 N.A N.A N.A 9–10 N.A

Total saturated FA 28.13 16.32 36–52 14.88 5–7 10.87

Total unsaturated FA 71.11 82.86 43–65 82.9 84 79.3

Calculated molecular weight

(kg kmol�1)

Fatty acid — 274 278 N.A 278 N.A 279

Oil — 864 868 N.A 871 N.A 874

Diesel fuel 170.27 — — — — — —

a;b;c; and d are taken from Al-Hasan (2000), Ozaktas et al. (1997), Tyson et al. (2004), and Applewhite

(1980), respectively. N.A: not available.

Kinast (2003), Cetane number and oxidative stability of PP oil will be better than that

of vegetable oils with a lower amount of saturated fatty acids, but it will be of poor cold

flow properties. The molecular weight, lower heating value, density, and viscosity of PP

oil are quite close to that of vegetable oils.

3.3. Combustion Performance

3.3.1. Stack Temperature. The variation of stack temperature (Tst ) of the combustion

unit at different relative air–fuel ratio (RAFR) for diesel fuel and PP oil-diesel fuel

blends is presented in Figure 2. As shown in the figure, nonlinear behavior of the stack

temperature was observed for all fuels. This behavior was expected, because the AFR

controlled the combustion quality and consequently the stack temperature. Therefore, at

slightly lean mixtures, when the RAFR was converging to stoichiometric, the Tst reached

its maximum values, while prior to and beyond stoichiometric, at rich and lean mixtures,

the Tst decreased. In addition, when the PP oil blended with diesel fuel, the Tst decreased

due to the decrease in the mixture heating values and to the presence of oxygen in the

fuel blends which decreased the combustion rate.

3.3.2. Combustion Unit Thermal Efficiency. The thermal efficiency (�th) is a measure

of how effectively the heat content of a fuel is transferred into usable heat, and can be

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Figure 2. Stack temperature against equivalence FAR for tested fuels.

determined, assuming boiler system, as follows:

�th DQw

Qf

DPmw � Cpw.Tin � Tout /

Pmf � LHV; (1)

where Qw is the actual heat transferred to the cooling water, Qf is the fuel input heat,

and Cpw (J kg�1K�1) is the water specific heat capacity.

The thermal efficiency as a function of the relative air-fuel ratio during the combus-

tion unit operation on diesel fuel and different fuel blends is shown in Figure 3. It is

obvious that the thermal efficiency reached its maximum value at slightly lean mixtures,

i.e., for RAFR equal to 1.05, 1.05, 1.0, and 1.0 for the diesel fuel and for the fuel blends of

5, 10, and 15% respectively, due to the optimum utilization of the fuel. At the same time

as 1.05 < RAFR < 1.0 the thermal efficiency decreases due to the lower reaction rate,

especially in lean mixtures, accordingly incomplete combustion of the fuel-air mixtures

occurs. Also from Figure 3, it can be observed that the thermal efficiency decreases

Figure 3. Thermal efficiency against equivalence FAR for tested fuels.

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when diesel fuel–PP oil blends were used instead of pure diesel fuel. This decrease can

be explained as follows: as can be seen in Table 3, the minimum amount of air needed for

complete combustion and the lower heating value of PP oil are lower than that of diesel

fuel while the lower heating values of stoichiometric air–PP oil mixtures (2.94 MJ kg�1)

and air-diesel fuel mixtures (2.96 MJ � kg�1) are very close. Therefore, when PP oil is

used, more oil was consumed to obtain the same output energy with the same amount of

air, thus decreasing the thermal efficiency. Furthermore, absorption of heat by the excess

air, due to presence of oxygen in PP oil which reduces the amount of heat transferred to

the furnace walls (water jacket), is another reason for thermal efficiency decrease.

4. Conclusions

An experimental study on PP oil was performed to determine both the elemental composition

and the combustion performance. The results were compared with pure diesel fuel and with

vegetable oils. The findings of this research can be summarized in the following points:

� The ultimate analysis and the consequent fatty acid composition of the PP oil differ

from the most common vegetable oils used in previous studies. On the one hand,

the PP oil is rich in oleic (47.76%), linoleic (19.07%), and palmitic (26.82%)

acids, while on the other hand, its molecular weight, lower heating value, and

density are very close to other vegetable oils.

� The stack temperature and the thermal efficiency of the combustion unit decreases

when the unit operates on PP oil–diesel fuel blends, due to the decrease in the

lower heating value of the fuel blends compared with diesel fuel.

� The major problem the researchers encountered was the high viscosity of PP oil

when used as an alternative fuel. Due to this problem, the maximum percentage

of the PP oil that can be added to diesel fuel with successful operation of the

combustion unit is 15%.

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Appendix A

A.1. Stoichiometric Air-fuel Ratio

The overall complete combustion equation (Heywood, 1989) is:

CaHb C

�

a Cb

4

�

.O2 C 3:377N2/ D aCO2 Cb

2.H2O/ C

�

a Cb

4

�

.3:77N2/: (A.1)

Based upon the ratio from Eq. (A.1), the molecular weights of oxygen, atmospheric

nitrogen, atomic carbon, and atomic hydrogen are 15.9994, 28.16, 12.011, and 1.008,

respectively. For PP oil:

C17:67H33:6O1:9 C 25:1.O2 C 3:77N2/ D 17:67CO2 C 16:8H2O C 25:1.3:77N2/: (A.2)

Thus, the stoichiometric AFR (kg kg�1) for PP oil is 12.56:1.

By using the previous procedures, the stoichiometric AFR for diesel fuel is 14.44.

For PP oil–diesel fuel mixture:

.AFR/mix D†.�i � �i � AFRi /

†.�i � �i/: (A.3)

A.2. Lower Heating Value (LHV)

If the elemental compositions of fuel are known, its LHV (MJ kg�1) can be estimated

using the Mendeleyev formula (Artamonov et al., 1976) as shown below:

LHV D 3391C C 125:6H � 10:89.Oy � S/ � 251.9H C W /; (A.4)

where C , H , Oy, S , and W represent the elemental composition of fuels (Table 2).

For PP oil–diesel fuel mixture:

.LHV /mix D†.�i � �i � LHVi /

†.�i � �i /: (A.5)

In Eqs. (A.2) and (A.4), the volumetric percentage, �i , of fuel constituent i is:

�i .%/ D

�

Vi

Vtot

�

� 100; (A.6)

where Vi and Vtot are the volume of the fuel of constituent i and the total volume of the

mixture respectively, �i is the constituent i fuel density.

Dow

nloa

ded

by [

Moh

amm

edf

Oda

t] a

t 07:

56 2

7 Ju

ly 2

011

pp oil paper

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