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Chapter – III
PROPERTIES OF VEGETABLE OILS USED IN TEST ENGINE
3.1
INTRODUCTION
The general morphology of oil plants and seeds and availability of oils are
explained. Combustion parameters such as density, viscosity, flash point,
fire point, cetane number and calorific value of all types of chosen oils and
their blends with diesel oil are presented in this chapter. Effect of blending
vegetable oil with diesel on viscosity is discussed. Effect of heating on
viscosity of oils and their blends with diesel is studied in this chapter.
3.2. GENERAL MORPHOLOGY OF PLANTS AND THEIR SEEDS
3.2.1 Linseed oil: Linseed oil, other wise known as flax seed oil or simply
flax oil. Its scientific name is Linum usitatissimum, (or)Linaceae.
The
yellowish drying oil is derived from dried ripe seeds of flax plant through
pressing and extraction. It is available in varieties such as Cold Pressed,
alkali refined, sun Bleached, sun thickened, and polymerized (stand oil)
marketed as flaxseed oil. Linseed oil is the most commonly used carrier in
oil paint. Several coats of linseed oil acts as the traditional protective coating
for the raw willow of a cricket bat. Fresh, refrigerated and unprocessed,
linseed oil is used as nutritional supplement. It is available in Asian
countries.
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3.2.2 Castor oil: Castor oil (or) ricinus oil is non-volatile fatty oil extracted
from Castor bean seeds. It varies in colour from colour less to greenish. It
has two derivatives known as blown castor and hydrogenated oil.
Hydrogenated castor oil is used in textiles, paints, varnishes, plastics,
cosmetics, fibers, hair oils and drying oils. It is also used in traditional
medical purpose. This oil also serves as a pregnant woman during delivery.It
is available in India and African countries.
3.2.3 Palm Stearin oil:
Palm oil has pleasant odour and taste.
It is stable and resistant to
rancidity. The colour of palm oil varies from yellow to deep orange. Inter
esterification of palm oil produces two fractions. Palm oil obtained at low
melting point called “Olein” and the oil obtained at high melting point called
“Stearin”. Oil palm fruits are oval-shaped sessile drupes. Palm oil contains
some triglyceride species, which are completely saturated. The iodine value
of palm oil is lower (44-58) when compared to other vegetable oils because of
high proportion of saturated fatty acids.
Palm oil is solid at ambient temperature and fluid in tropical and
subtropical climates with certain fractions held in crystalline form.
used in manufacturing plastics, fibers and soaps.
It is
It is available in Asia,
Africa, Indonesia, Nigeria and Malaysia.
3.2.4 Mahua oil: Scientific name of Mahua oil is “Madhuka indica”,
botanical name is “Madura long folia”. It is derived from a tropical tree
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belonging to the family Sapotaceae. The other Vernacular names of Mahua
are Madhukha in Sanskrit, Maduca or butter tree in English, Mohua in
Hindi, Mahuva In Urdu, Ireppa (or) Elippa in Malayalam, Ippa (or) Ippachittu
in Telugu, Monda in Marathi. Almost all parts of this tree, which includes
leaves, flowers, roots, bark, latex juice, seed and are known to possess
medicinal properties. So, it is widely used in traditional medicine.
The leaves of Mahua are astringent and they are used in embrocation. The
bark is used for rheumatism, ulcers and diabetic mellitus. It is used to cure
burning sensation in the body, debility emaciation, respiratory diseases,
rheumatism and thirst. It is considered useful in snake bite and fish poison
cases. Flowers can be used to treat cough, cold and bronchitis. Flowers are
largely used in processing distilled liquors. The roots are applied to cure
ulcers. In vetenary medicine, it is used to treat stomach ache in horses.
Leaves are used as cattle fodder and green manure. The last, but not least is
the bio-diesel properties of Mahua seed oil. The methanolic extract of
flowers, leaves, stem and stem bark has been reported to posses
antibacterial activity against B anthracis, B pumilus, viz Cholera, xanth etc.
It is available in Asian and western countries.
3.2.5 Neem oil:
The scientific name of Neem is azadirachta indica. It belongs to the family
meliaceae. The kernels contain 40% to 50% of an acrid bitter greenish yellow
to brown oil with strong disagreeable garlic like odour. This bitter taste is
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due to the presence of sulphur containing compounds like Nimbin, Nimbidin
and Nimbosterol. It is rich in oleic acid, followed by Stearic, Palmitic and
Linolenic
acids.
The
oil
is
used
for
illumination,
soap
making,
pharmaceuticals, cosmetics and medicinal fields (Ayurvedic medicine).The
purified oil is used in manufacturing disinfect able and emulsifying agents
which are used as insecticidal sprays. Neem oil is available in India and
West Africa.
3.3. CHARACTERISTICS OF VEGETABLE OILS
The important physical and chemical properties of Linseed oil , Castor oil,
Palm stearin oil, Mahua oil and Neem oils are determined by using Indian
Standard(IS:1448) instrumentation in fuels and lubricants laboratory of
Mechanical engineering
department. Determination of density, calorific
value, viscosity, flash point, fire point are
carried out using Hydrometer,
Bomb calorimeter, Red wood viscometer and Able’s apparatus respectively.
Table 3.1 shows the comparison of combustion parameters of vegetable oils
used at 400C.
Density for all types of oils used is higher than that of diesel. Density of
castor oil is 0.956 gm/cc, which is higher than that of other types of oils
used. The lowest density among all chosen oils is 0.917 gm/cc.
Viscosity of all types of oils used is higher than that of diesel. In which
Viscosity of castor oil is highest (52 cst) followed by palm stearin, Mahua,
Neem and Linseed oil compared to Diesel.
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Flash point and fire point of all types of oils used are higher than that of
Diesel. The flash and fire point of Castor oil is 3200C and 3450C respectively,
which is the highest compared to other types of oils used.
Calorific value of all types of oils used is lower than that of Diesel. Calorific
value of vegetable oil under test is in the range of 85%- 95% to that of
Diesel.
Cetane numbers of all oils chosen are lower than that of Diesel oil.
3.4. EFFECT OF BLENDING VEGETABLE OILS WITH DIESEL ON
VISCOSITY
All types of vegetable oils are blended with diesel in 0/100, 25/75, 50/50,
75/25 and 100/0 percent on volume basis and the mixture is stirred well to
get a homogeneous stable mixture. Variation of density, viscosity and
percentage reduction in viscosity of blends at 400C for Linseed, Castor, Palm
sterin, Mahua and Neem oils are given in the Table 3.2- 3.6 respectively.
The density and viscosity of blends reduce with the increase in percentage
of diesel in blends. Blends contain 25% vegetable oil and 75% diesels have
density and viscosity close to those of Diesel.
3.5 EFFECT OF TEMPERATURE ON VISCOSITY OF VEGETABLE OIL
AND ITS BLENDS WITH DIESEL
The graphs from Fig.3.1 to 3.5 shows that the viscosity of vegetable oils
reduces with increase in temperature from 300C to 800C according to the
percentage of neat vegetable oil mixed with diesel.
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The blend containing 25% of all types of neat vegetable oils with 75% diesel
does not require any pre heating before entering into the combustion
chamber as per the analysis of graphs from fig.3.1 to 3.5.
It is evident from the graphs of Viscosity Vs Temperature that the drop in
viscosity of neat oils and their blends with increase in temperature is more
compared to that of pure diesel oil.
3.6 Conclusions
The general morphology of all five types of vegetable oils, their availability
and combustion parameters of all types of non-edible vegetable oils and
their blends with diesel oil are presented. Effect of blending vegetable oil
with diesel on viscosity is discussed. Effect of temperature on viscosity of
vegetable oils and their blends with diesel are studied and presented. From
the above investigations the following conclusions are drawn:
 The properties such as density, viscosity, flash point and fire point of
all used vegetable oils are higher and calorific values are lower
compared to diesel. Calorific values of oils are in the range of 85%95% to that of diesel.
 The density and viscosity of all used vegetable oil blends reduce with
increase in percentage of diesel in blend. The blends containing 25%
vegetable oil and 75% diesel have density and viscosity close to that of
diesel at 400C . Hence the oil doesn’t require any heating before
entering into the combustion chamber.
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 To reduce the viscosity of all types of oils, the blends such as
50%,75%,100% vegetable oil with diesel are heated ranging from
700C to 1200C before entering into the combustion chamber.
 To reduce the viscosity of all types of oil and their blends, they are
heated to the following temperature
before entering into the
combustion chamber
50% blends
: 700C – 800C
75% blends
: 800C – 900C
100 % vegetable oil (Neat oils)
: 950C -1200C.
Table 3.1 Comparison of combustion parameters of vegetable oils
used in test Engine.
property
Linseed Castor
Palm
Mahua
Neem
Diesel
stearin
Density(gm/cc)at 0.929
0.956
0.918
0.917
0.919
0.830
400C
Viscosity(cst)
22.2
52
39.6
36
34
5.0
Flash point(0C)
241
320
220
273
300
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Fire point(0C)
260
345
280
301
325
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Calorific
39307
36000
37500
39600
35200
42000
34.6
42.3
42
45
38
50
values(KJ/Kg)
Cetane number
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Table .3.2. Properties of Linseed oil – diesel blends
Linseed
Diesel (%)
oil (%)
Density(gm/cc)
Viscosity(cst)
Viscosity
at 400C
at 300C
reduction (%)
100
0
0.929
22.2
75
25
0.904
20
9.90
50
50
0.880
17
23.42
25
75
0.855
10
54.95
0
100
0.840
5
77.47
-
Table .3.3. Properties of Castor oil – diesel blends
Castor oil
Diesel (%)
(%)
Density(gm/cc)
Viscosity(cst)
Viscosity
at 400C
at 300C
reduction (%)
100
0
0.956
52
-
75
25
0.925
41
21.53
50
50
0.893
35
32.69
25
75
0.862
15
71.15
0
100
0.840
5
90.38
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Table .3.4. Properties of Palm Sterin oil – diesel blends
Palm
Diesel (%)
Sterin oil
Density(gm/cc)
Viscosity(cst)
Viscosity
at 400C
at 300C
reduction (%)
(%)
100
0
0.918
39.6
-
75
25
0.902
35
11.61
50
50
0.885
26
34.34
25
75
0.860
15
62.12
0
100
0.835
5
87.37
Table .3.5. Properties of Mahua oil – diesel blends
Mahua oil
Diesel (%)
(%)
Density(gm/cc)
Viscosity(cst)
Viscosity
at 400C
at 300C
reduction
(%)
100
0
0.917
36
-
75
25
0.895
30
16.66
50
50
0.874
22
38.88
25
75
0.852
18
50
0
100
0.840
5
86.11
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Table .3.6. Properties of Neem oil – diesel blends
Neem oil
Diesel (%)
(%)
Density(gm/cc)
Viscosity(cst)
Viscosity
at 400C
at 300C
reduction
(%)
100
0
0.919
34
-
75
25
0.897
30
11.76
50
50
0.875
22
35.29
25
75
0.853
14
58.82
0
100
0.840
5
85.29
Fig. 3.1. Variation of Viscosity of Linseed oil and its blends with
Temperature.
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Fig. 3.2. Variation of Viscosity of Castor oil and its blends with
Temperature.
Fig. 3.3. Variation of Viscosity of Palm Stearin oil and its blends
With Temperature
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Fig. 3.4. Variation of Viscosity of Mahua oil and its blends
With Temperature
Fig. 3.5. Variation of Viscosity of Neem oil and its blends with
Temperature