Bio Diesel from Castor Oil – A Green Energy Option

doi:10.4236/lce.2011.21001

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Low Carbon Economy, 2011, 2, 1-6

doi:10.4236/lce.2011.21001 Published Online March 2011 (http://www.SciRP.org/journal/lce)

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.

Email: [email protected]

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

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

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

• 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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