Low Carbon Economy, 2011, 2, 1-6
doi:10.4236/lce.2011.21001 Published Online March 2011 (http://www.SciRP.org/journal/lce)
1
Bio Diesel from Castor Oil - A Green Energy
Option
Hemant Y. Shrirame1, N. L. Panwar2, B. R. Bamniya3
1College of Agricultural Engineering and Technology, Dr. B. S. Konkan Krishi Vidyapeeth, Maharashtra, India; 2Department of Re-
newable Energy Sources, College of Technology and Engineering Maharana Pratap University of Agriculture and Technology, Ra-
jasthan, India; 3Department of Environmental Sciences, Mohan Lal Sukhadia University, Udaipur, Rajasthan, India.
Received February 5th, 2011; revised February 12th, 2011; accepted February 26th, 2011.
ABSTRACT
With increase in the demand of petroleum products the prices of petrol & diesel are increasing world wide. This trend
is expected in years to come as the resources are also depleting. Hence alternative sources of energy for running our
generators, automobiles etc. are being considered world wide. The possibility of obtaining oil fro m plant resources has
aroused a great interest and in several countries, vegetable oil after esterification being used as “Biodiesel”. The bio-
diesel can be used as 20% blend with petrodiesel in existing engin es without any modifica tion. Both th e ed ible a nd non
edible vegetable oils can be used as the raw materials for the biodiesel. Considering the cost and demand of the edible
oils the non edible oils may be preferred for the preparation of biodiesel in India.
Keywords: Biodiesel, Castor Seed Oil, Emissions, Green Energy, Non Edible Oil
1. Introduction
Energy is the basic need for economic development of
any country. The single largest source of energy in India
after coal is petroleum, about two third of which is im-
ported from OPEC (Oil and Petroleum Exporting Coun-
tries). In India energy consumption is increasing at rapid
rate due to rapid industrialization, transportation and
mechanization. At present, India is the sixth biggest
country in the world and second highest country after
china in Asia in terms of energy demand. High depend-
ency on imported fuel and due to rapid rise in petroleum
prices may make Indian economy insecure from energy
demand.
As per Planning Commission (Government of India)
estimates, the requirement of petrol is expected to grow
from approximately 7 million tons in 2001 to 10 million
tons in 2006 and 12.5 million tons in 2012. Similarly, the
demand for diesel is likely to touch the level of about 52
million tons in 2006 and 66 million tons in 2012.
Coal is the most important & abundant fossil fuel in
India and accounts for 55% of India’s energy need. In-
dia’s industrial heritage was built upon indigenous coal,
largely mined in the eastern and the central regions of the
country. Thirty per cent of commercial energy require-
ments are met by petroleum products, nearly 7.5 percent
by natural gas and 3.5 percent by primary electricity.
India is, however, poorly endowed with oil assets and
has to depend on crude imports to meet a major share of
its needs (around 70 percent). A large population of India
in the rural areas depends on traditional sources of en-
ergy such as firewood, animal dung and biomass. The
usage of such sources of energy is estimated at around
approximately 47 percent of total primary energy use.
2. Biodiesel
Biodiesel is the product one gets when organically de-
rived oil such as vegetable oil or animal fat chemically
reacts with an alcohol to produce a fatty acid alkyl ester
[1]. It has become an interesting alternative to be used in
diesel engine, because it has similar properties to the
traditional fossil diesel fuel and may, thus, substitute
conventional fuel with none or very minor engine modi-
fication [2]. One of the attractive features of biodiesel is
its biodegradability and being more environmental friendly
than the fossil fuels, resulting in less environmental im-
pact upon accidental release to the environment [3]. Emis-
sions such as total hydro carbons and CO are usually
found to significantly low with biodiesel as compared to
petroleum diesel. This may be due to more complete
combustion caused by the increased oxygen content in
the flame coming from the biodiesel molecules. It is al-

Bio Diesel from Castor Oil – A Green Energy Option 2
ways recommended to produce biodiesel use waste edi-
bles oil or non-edibles oil such as jatropha, caster, pon-
gamia pinnata, rubber seed and mango. Table 1 shows
oil yield of major non-edible and edible oil [4].
Jaecker-Voirol et al., [6] reported an emission per-
formance test for various biodiesel formulations in-
cluding di- and tri-glyceryl ethersbiodiesel blends re-
leasing less regulated and toxic air pollutants compared
with biodiesel alone. However, the use of isobutene to
produce di- and tri-glyceryl ethers from glycerol needs
further research as isobutene is expensive, currently made
from non-renewable source and requires high pressure for
the glycerol etherification reaction. A study was reported
in Indian context that if 10% of total production of castor
seed oil is transesterfied into biodiesel, then about 79,782
tons of CO2 emission can be saved on annual basis. The
CO2 released during combustion of biodiesel can be re-
cycled through next crop production, therefore, no addi-
tional burden on environment [7].
3. Energy Security
Increasing pressure of population and increasing use of
energy in agriculture, industrial and the domestic and
public sectors is an area of concern. At the same time, the
need to meet energy demand has created huge capital
requirements needed for setting up power plants, pipe-
lines, ports, terminals, railway tracks to move fuel etc.
As India continues to grow at the rate of 8-9.5 per-
cent, energy security has become a core issue. To allevi-
ate concerns over energy security, the Government of
India has taken multiple steps in recent years which in-
clude encouraging private sector participation, a more
holistic approach towards broad basing its supply base,
and improving efficiency in the sector as a whole [8].
High Speed Diesel (HSD) is the main transport fuel in
Table 1. Oil yield for major non-edible and edible oil sources.
Type of oil Oil yield (kg oil/ha) Oil yield (wt%)
Non-edible oil
Jatropha 1590 Seed: 35 - 40
kernel: 50 - 60
Rubber seed 80-120 40-50
Castor 1180 53
Pongamia pinnata 225 - 2250 30 - 40
Sea mango N/A N/A
Edible oil
Soybean 375 20
Palm 5000 20
Rapeseed 1000 37 - 50
India, hence introduction of biodiesel both as a diesel
substitute and for blending with diesel is an imperative
need. Mainly, biodiesel is being produced by the crops
like sunflower, soybean, mustard oil etc in many parts of
the world. As the nation is facing a shortage of edible
oils, it would not be feasible to produce biodiesel by edi-
ble oils. However, the country has enormous potential to
produce tree borne oilseeds for biodiesel production to
cope with the demand of about 40 percent diesel re-
quirement from total crude oil.
Biodiesel is nothing but fatty acid methyl or ethyl es-
ters made from edible and non-edible oils and animal fats.
The main commodity sources for biodiesel in India can
be non-edible oils obtained from plant species such as
Ratanjot (Jatropha curcus), Karanja (Pongamia pinnata),
Castor (Ricinus communis) oilseed etc. It contains no
petroleum, but it can be blended at any level with petro-
leum diesel to create a biodiesel blend or can be used in
its pure form [9,10]
4. Castor Oil
A colorless or pale yellowish oil extracted from the seeds
of the castor-oil plant, Castor (Ricinus communis L) is
cultivated around the world because of the commercial
importance of its oil which is used in the manufacture of
a number of industrial chemicals like surfactants, greases
and lubricants, specialty soaps, surface coatings, cosmet-
ics and personal care products, pharmaceuticals, etc.
The Indian variety of castor seed has an oil content of
48% and 42% can be extracted. The residual oil cake,
which contains about 5.5 percent Nitrogen, 1.8-1.9 per-
cent Phosphorus and 1.1 percent Potassium, is used as
organic manure. Castor grows well under hot and humid
tropical conditions and has a growing period of 4 to 5
months. It can be grown either as a pure crop in rotation
with wheat, linseed etc., or is grown mixed with cotton,
groundnut, arhar, green gram, jowar, bajra and cowpea.
The average yield of seed per hectare and oil per hectare
is 1250 kg/hectare and 550 lit/hectare India is the world’s
largest producer and exporter of castor oil [11]. It is cur-
rently cultivated on about 700,000 hectares mostly in
Gujarat and Andhra Pradesh under rain fed conditions.
The yield in terms of oil varies from 350-650 kg of oil
per hectare when no maintenance is applied to the crop
i.e. fertilizers etc. [12].
The comparative advantage of Castor is that its grow-
ing period is much shorter than that of Jatropha and
Pongamia, and there is considerably greater experience
and awareness among farmers about its cultivation. Be-
ing an annual crop it gives the farmers the ability to
rotate or shift away easily depending on market condi-
tions.
However, among vegetable oils, castor oil is distin-

Bio Diesel from Castor Oil – A Green Energy Option 3
guished by its high content (over 85%) of ricinoleic acid.
No other vegetable oil contains so high a proportion of
fatty hydroxyacids. Castor oils unsaturated bond, high
molecular weight (298), low melting point (5˚C) and
very low solidification point (−12˚C to −18˚C) make it
industrially useful, most of all for the highest and most
stable viscosity of any vegetable oil. The physical prop-
erties of the vegetable oils are shown in Table 2. The
physical and chemical properties of the methyl esters
produced are shown in Table 3. The values are compared
with ASTM standard for bio diesel.
5. The Chemical Composition of Castor Oil
is [12]
• Ricinoleic Acid − 89.5%
• Linoleic Acid − 4.2%
• Oleic Acid − 3%
• Stearic Acic − 1%
• Palmitic Acid − 1%
• Dihydroxystearic Acid − 0.7%
• Linolenic Acid − 0.3%
• Eicosanoic Acid − 0.3%)
5.1. Cost of Castor Oil
The following were the spot prices for the various oils in
India on March 10, 2006 in Indian rupees/Kg (One US $
equals 45 Indian rupees, approximately).
• Castor Oil − 32.3
• Groundnut Oil/Peanut Oil − 43.6
• Mustard Oil − 36.4
Table 2. Physical properties of the vegetable oils.
Oil
Kinematic Vis-
cosity at 20˚C
(×10-6m2s-1)
Kinematic Vis-
cosity at 40˚C
(×10-6m2s-1)
Kinematic vis-
cosity at 70˚C
(×10-6m2s-1)
Density
(kgm-3)
Acid value
(mgKOH/g)
Glycerol
(wt%) Miscible
Castor 961 268 61.9 993 0.022 4.12 Between 70%
and 100% oil
Cotton seed 85.0 43.7 23.2 951 7.073 18.40 0-100% oil
Groundnut 91.8 41.4 27.6 942 3.185 5.43 0-100% oil
Moringa oil 53.7 39.1 21.7 919 22.754 11.47 insufficient oil
Rubber seed 44.0 39.9 33.0 920 10.814 4.00 insufficient oil
Soya bean 74.1 35.8 30.7 950 0.669 5.50 0-100% oil
Sunflower 78.9 45.6 24.7 953 2.124 7.64 0-100% oil
Petroda
Diesel 22.8 12.3 8.53 879 4.17 × 10-4 0.70 −
ASTM
Standard − 1.9-6.0 − − 0.8 max 0.02 max −
(Sources: http://www.chanco.unima.mw/physics/biodieselanaly.html)
Table 3. Physical and chemical properties of the methyl esters.
Methyl Ester
Kinematic
Viscosity at 20˚C
(×10-6m2s-1)
Kinematic
Viscosity at 40˚C
(×10-6m2s-1)
Kinematic
Viscosity at 70˚C
(×10-6m2s-1)
Density
(kgm-3)
Acid Value
(mgKOH/g) Glycerol (wt%)
Castor 40.6 19.4 15.8 956 6.24 × 10-3 80.39
Cotton seed 25.0 23.1 16.1 921 2.04 × 10-3 3.44
Groungnut 22.0 15.4 7.16 908 7.20 × 10-4 1.03
Moringa 22.4 13.3 11.1 903 2.13 × 10-3 0.81
Rubber seed 23.9 21.7 19.8 891 6.29 × 10-3 21.91
Soya bean 18.8 11.1 6.56 915 1.56 × 10-3 8.69
Sunflower 18.9 13.2 8.80 909 3.07 × 10-3 4.46
petroda Diesel 22.8 12.3 8.53 879 6.24 × 10-3 0.7
ASTM standard − 1.9-6.0 − − 0.8 max 0.02 max
(Sources: http://www.chanco.unima.mw/physics/biodieselanaly.html)

Bio Diesel from Castor Oil – A Green Energy Option 4
• Palm Oil (RBD) − 38.1, Palm Oil Crude − 36.4
• Refined Soy Oil − 36.7
5.2. Typical Extractions of Oil from Oilseeds
(Kg of oil from 100 kg of oilseed)
Oilseed Extraction
Castor 36
Palm 36
Rapeseed 37
Soybean 14
Sunflower 32
5.3. Yield Comparison of Castor Oil with Other
Plant Oil Biodiesel Candidates
Crop Oil in Liters per hectare
Castor 1413
Sunflower 952
Safflower 779
Palm 5950
Soy 446
Coconut 2689
6. World Scenario
India is the leading producer of castor oil in the world,
followed by China and Brazil with 0.8 and 0.4 lakh tons
respectively. The present annual world trade in castor oil
is estimated at about 2.0-2.50 lakh tons. The major im-
porters of castor oil in the world market are European
Union, US and Japan. The world demand for castor oil is
estimated to be growing at the rate of about 3 to 5 % per
annum. Both Brazil and China have experienced a steady
increase in their domestic castor oil consumption in the
recent years and thus utilize almost their entire produc-
tion. India consumes only a quarter of its castor oil pro-
duction and exports the rest [13].
6.1. Indian Scenario
• India is the world leader in castor seed and oil
production and dominates the international castor
oil trade.
• The Indian variety of castor has 48% oil content of
which 42% can be extracted, while the cake retains
the rest.
• India’s castor oil production fluctuates between
2.5-3.5 lakh tons a year. In 2003-04, India’s esti-
mated castor oil production was 2.8 lakh tons.
• Gujarat accounts for 86% of India’s castor seed
production followed by Andhra Pradesh and Ra-
jasthan. Castor is mainly grown in Mehsana, Banas-
kantha and Saurashtra/Kutch regions of Gujarat and
Nalgonda and Mahboobnagar districts of Andhra
Pradesh.
• Castor is a Kharif crop. The sowing season of cas-
tor is from July to October and the harvesting sea-
son is from October to April.
• The annual domestic consumption of castor oil in
India is only about 80 000-100 000 tons. Of this,
the soap industry consumes about 25 000 tons, the
paint and allied industries 35 000 tons and the lu-
bricant and derivatives industry 20,000 tons.
• India annually exports around 2.0-2.4 lakh tons of
commercial castor oil. From India castor oil is ex-
ported in two forms - First Special Grade and Cas-
tor Oil Commercial through mainly Kandla port.
There is a large scope for improving India’s earning
from castor by converting the castor oil to various
derivatives.
• A considerable quantity of the castor oil is also
used in adulteration of edible oils like groundnut
oil due to price differential.
6.2. Castor Oil in Food
In the food industry, Castor oil (food grade) is used in
food additives, flavorings, candy (i.e., chocolate), as a
mold inhibitor, and in packaging. Polyoxyethylated Cas-
tor oil is also used in the foodstuff industries [14].
6.3. Medicinal Use of Castor Oil
Today, the United States Food and Drug Administration
(FDA) recognizes Castor oil as generally safe and effect-
tive (GRASE) for over-the-counter use as a laxative, but
it is not a preferred drug to treat constipation. Besides
being a laxative, Castor oil is sometimes used to help
women start labor, but in any case with due caution and
under medical supervision. One of Castor oil’s deriva-
tives undecylenic acid is also FDA approved for over-
the-counter use on skin disorders or skin problems.
7. Energy Content of Biofuels
The specific energy densities (MJ/kg) of various fuels
7.1. Solid Fuels
Wood Fuel – 16-21
7.2. Liquid Fuels
Methanol – 20-23
• Ethanol – 24-27
• Butanol - 36
• Biodiesel - 38
7.3. Gaseous Fuels
Methane – 55-56
• Hydrogen – 120-140
7.4. Fossil Fuels (for Comparison)
• Coal – 29-34

Bio Diesel from Castor Oil – A Green Energy Option5
8. Advantages of Biodiesel
Advantages & Benefits,
• Biodiesels are biodegradable, non-toxic, less green-
house gases emissions than petroleum-based diesel,
renewable source of energy.
• Biodiesel is the only alternative fuel that runs in
any conventional, unmodified diesel engine.
• Biodiesel can be used alone or mixed in any ratio
with petroleum diesel fuel. The most common blend
however is a mix of 20% biodiesel with 80% pe-
troleum diesel, or “B20”.
• Biodiesel is about 10% oxygen by weight and con-
tains no sulfur. The lifecycle production and use of
biodiesel produces approximately 80% less carbon
dioxide emissions, and almost 100% less sulfur
dioxide.
• Combustion of biodiesel alone provides over 90%
reduction in total unburned hydrocarbons, and a
75-90% reduction in aromatic hydrocarbons.
• Biodiesel has a very high flash point (300 F) mak-
ing it one of the safest of all alternative fuels, from
a combustibility point.
9. Bio-Diesel Produced from Castor Oil
The major problem associated with the use of pure vege-
table oils as fuels for diesel engines is caused by high
fuel viscosity in compression ignition. The vegetable oils
are all highly viscous, with viscosities ranging 10-20
times those of No. 2 Diesel fuel. Amongst vegetable oils
in the context of viscosity, castor oil is in a class by itself,
with a viscosity more than 100 times that of No. 2 Diesel
fuel (MSDS of No. 2 Diesel Fuel − PetroCard). Due to
their high viscosity and low volatility, they do not burn
completely and form deposits in the fuel injector of die-
sel engines. Furthermore, acrolein (a highly toxic sub-
stance) is formed through thermal decomposition of
glycerol.
Dilution, micro-emulsification, pyrolysis and transes-
terification are the four techniques applied to solve the
problems encountered with the high fuel viscosity.
Amongst the four techniques, chemical conversion of the
oil to its corresponding fatty ester is the most promising
solution to the high viscosity problem. This process -
chemical conversion of the oil to its corresponding fatty
ester, and thus biodiesel − is called transesterification
[15].
9.1. Transesterification Process
The transesterification process will be adopted for the
preparation of ethyl ester or methyl ester of Castor
(Ricinus communis) oil. In the preparation of ethyl ester
(biodiesel), five distinct stages will be involved,
1) Heating of oil.
2) Preparation of alkaline mixture.
3) Adding of alkaline alcohol to oil and stirring the
mixture.
4) Settling of separation of glycerol.
5) Washing of ethyl ester with water.
The biodiesel can be obtained by transesterification of
castor oil using either ethanol or methanol as the Trans-
esterification agent. The extraction of biodiesel from cas-
tor oil, in the presence of the catalysts faster with methanol
as the transesterification agent compared with ethanol.
The maximum yield of esters depends on the reaction
time and that is 1 hour with methanol or of 5 hours with
ethanol. However, while similar yields of fatty acid es-
ters may be obtained following ethanolysis or metha-
nolysis, the reaction times required to attain them are
very different, with methanolysis being much more rapid
[16]. The transesterification of castor oil via ethanolysis
or methanolysis can be improved through the develop-
ment of more efficient catalytic systems and processes, to
maintain kinetic control of the reaction, and by optimiza-
tion of purification procedures.
10. Conclusions
The vegetable oil-based fuel production is very attractive
for developing countries like India. Vegetable oils are a
renewable and potential inexhaustible source of energy
with an energetic content close to diesel fuel. In addition
to being available locally, renewable and cheap, biodiesel
can make a good substitute for diesel fuel. The biodiesel
is found to burn more efficiently than diesel [17]. The
emission of carbon monoxide, hydrocarbon, oxides of
nitrogen and smoke were decreased by 58, 63, 12 and 70
percent, respectively, in comparison with diesel.
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