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Chapter 1

Introduction

1.1 General Introduction: Biodiesel

The world is presently confronted with the twin crises of fossil fuel depletion and

environmental degradation. Indiscriminate extraction and lavish consumption of fossil

fuels have led to reduction in reserve carbon resources. The search for alternative fuels,

which promises a harmonious correlation with sustainable development, energy

conservation, efficiency and environmental preservation, has become highly

pronounced in the present context. Bio-fuels can provide a feasible solution to this

worldwide petroleum crisis. Scientists around the world have explored several

alternative energy resources that have a potential to quench the ever-increasing energy

thirst of today's population. Various biofuel energy resources explored include biomass,

biogas, primary alcohols, vegetable oils, biodiesel, etc. These alternative energy

resources are largely environment friendly but they need to be evaluated on case-to-

case basis for their advantages, disadvantages and specific applications. Some of these

fuels can be used directly while others need to be formulated to bring the relevant

properties closer to conventional fuels. The present energy scenario has stimulates the

active research interest in non-petroleum, renewable and non-polluting fuels.

Time is ripe to strike a balance between energy security and energy usage in the

face of enormous growth of world population, increased technical development and

standard of living in the industrial nations. The prices of crude oil keep rising and

fluctuating on a daily basis. The variation in the energy prices over last decade has

necessitated development of commercial fossil fuel alternatives from bio-resources.

Several sources of energy, especially for driving the automotive are being

developed and tested. This may well be the main reason behind the growing awareness

and interest for non-conventional bioenergy sources and fuels in various developing

countries which are striving hard to offset the oil monopoly. This introduction presents


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detailed information on biodiesel together with its emission benefits and the prospects

of biodiesel as an alternative source from non-edible oil.

Bio-diesel is a fast-developing alternative fuel in many developed and developing

countries of the world. A number of feedstock options for production of bio-fuel have

been considered in different countries (Bhasabatra & Sutiponpeibum 1982 a, b).

1.2. Global biofuel scenario

Biomass has been recognized as a major world renewable energy source to

supplement declining fossil fuel resources. Biomass appears to be an attractive

feedstock for three main reasons. First, it is a renewable resource that could be

sustainably developed in the future. Second, it appears to have formidably positive

environmental benefits with no net releases of carbon dioxide (CO2) and very low sulfur

content. Third, it appears to have significant economic potential provided that fossil fuel

prices increase in the future. Ligno-Cellulosic bio-methanol also have low emissions

because the carbon content of the alcohol is primarily, derived from carbon that was

sequestered in the growing of the bio-feedstock and is only being re-released into the

atmosphere.

Transports sector is a major consumer of petroleum. Fuels such as diesel,gasoline, liquefied petroleum gas (LPG) and compressed natural gas (CNG).This sector is

likely to suffer badly because of following reasons: (a) Prices of petroleum in global

market have a raising trend; (b) Petroleum reserves are limited and it is a monopoly of

some oil-importing countries and rest of the world depends on them; (c) Number of

vehicles based on petroleum fuels is on increase worldwide. Many research programs

recently focused on the development of concepts such as renewable resources,

sustainable development, green energy, eco-friendly process, etc. in the transportationsector. In developed countries there is a growing trend towards employing modern

technologies and efficient bio-energy conversion using a range of biofuels, which are

becoming cost-wise competitive with fossil fuels. Advantages of bio-fuels are the

following:(a) Bio-fuels are easily available from common biomass sources; (b) they


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reduce CO2 footprints (c) bio-fuels are environmentally friendly; (d) they help in energy

security and improve economy; (e) they are biodegradable and contribute to

sustainability. Renewable resources are more evenly distributed than fossil and nuclear

resources, and energy flows from renewable resources are more than three orders of

magnitude higher than current global energy use. Todays energy consumption is

unsustainable because of equity issues as well as environmental, economic and

geopolitical concerns that have implications far into the future

1.3. What is biodiesel?

Biodiesel is considered as clean fuel that contains no petroleum, no sulphur, and

no aromatics; therefore it can be blended at any level with petroleum diesel to create a

bio-diesel blend or can be used as neat. Just like petroleum, biodiesel operates in

compression ignition that essentially require very little or no engine modifications

because biodiesel has properties similar to petroleum diesel fuel. It can be stored just

like the petroleum diesel fuel and doesnt require separate infrastructure. The use of

bio-diesel in conventional diesel engines results in substantial reduction of un-burnt

carbon monoxide, hydrocarbons and particulate matters. It has about 10% built in

oxygen that helps it to burn efficiently. Its higher cetane number improves the ignition

quality even when blended with petroleum diesel.

The best way to use non-edible oil as fuel is to convert it in to biodiesel.

Biodiesel is the name of a clean burning mono-alkyl ester-based oxygenated fuel made

from natural, renewable sources such as new/used vegetable oils and animal fats. The

resulting biodiesel is quite similar to conventional diesel in its main characteristics.

Biodiesel contains no petroleum products, but it is compatible with conventional diesel

and can be blended in any proportion with mineral diesel to create a stable biodiesel

blend. The level of blending with petroleum diesel is referred as Bxx, where xx indicates

the amount of biodiesel in the blend (i.e. B10 blend is10% biodiesel and 90% diesel. It

can be used in CI engine with no major modification in the engine hardware.


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1.4 Biodiesel production

The general process of biodiesel production is shown in reaction above. A fat or

oil reacts with an alcohol in the presence of a catalyst to produce glycerin and methyl

esters or biodiesel. The methanol is charged in excess to assist in quick conversion and

recovered for reuse. The catalyst is usually sodium or potassium hydroxide shown in

reaction 1, Charts 1 & 2.

Reaction 1:- General chemical reaction process of biodiesel production

CH2-O-COR KOH, 6h CH2-OH

| |

CH-O-COR + 3ROH 3RCOOR + CH-OH

| |

CH2-O-CO-R CH2-OH

(1 kg) (450 gm) (10 gm) (98 kg) (10gm)

Oil Alcohol Bio diesel Glycerin

Chart 1:- Basic scheme for Biodiesel production


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Chart 2:- General process of biodiesel production

1.5 Characteristics of biodiesel

1.5.1 Physical properties

Table 1: Comparison of the physico-chemical parameters of the investigated sample

to ASTM and EN standards

Parameter ASTM

diesel

ASTM

biodiesel

EN-diesel EN-

biodiesel

Crude oil Transesterified

Biodiesel

Color Gold.

yellow

Gold.

yellow

Gold.

yellow

Gold.

yellow

Gold.

yellow

Gold. yellow

Kinematic

viscosity

mm2/s

2.4-4.1 1.9-6.0 2.0-4.5 3.5-5 27-11 4-8

Specific

gravity

- - 0.820-

0.845

86-0.90 0.92 0.87

Free fatty

acid (%)

- - - - 3.1 0.25

Acid value

(mg KOH/g)

- 0.80 - 0.50 6.3 0.49

Source: - Traore S. et al (2007)

n

Reactor Settler Washing Purification Evaporation

Alcohol

Recover

NeutralizationDistillation

Settler Evaporation

Alcohol

Non- edible oil

Catalyst

Mineral

Fatty Acid

Glycerin

Biodiesel


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Investigated properties and the range of color, kinematic viscosity, specific

gravity, free fatty acids and acid value in ASTM diesel and biodiesel, EN diesel, crude oil

and transesterified biodiesel are presented on Table 1.

1.5.2 Emission Characteristics

The methods, limits, unit of emission characteristics of pure biodiesel according

to the ASTM specification are given in Table 2.

Table 2:- ASTM Specification for B100 limit

*The carbon residue shall run out in the 100% sample

Source: Canaki M. (2007)

Biodiesel is the only alternative fuel to have a complete evaluation of emission

results and potential health effects submitted to the U.S. EPA under the Clean Air Act

Section 211(b). These programs include the most stringent emissions testing protocols

ever required by EPA for certification of fuels in the U.S. Emission results for pure

biodiesel (B100) and mixed biodiesel (B20-20% biodiesel and 80% petro diesel)

compared to conventional diesel are given in Table 3.

Property ASTM Method Limits Units

Flash Point D93 130 min. C

Water & Sediment D2709 0.050 max. % VolumeKinematic Viscosity (40degree C) D445 1.9-6.0 mm2/sec

Sulfated Ash D874 0.020 max. % mass

Sulphur D5453 0.05 max. % mass

Copper Strip Corrosion D130 No.3 max.

Cetane number D613 47 min.

Cloud Point D2500 Report C

Carbon Residue (100% Sample) D4530* 0.050 max. % mass

Acid Number D664 0.80 max. mg KOH/g

Free Glycerin D6584 0.020 max. % mass

Total Glycerin D6584 0.240 max. % mass


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Table 3:- Biodiesel emissions comparison to conventional diesel

Emissions B100 B20

Regulated Emissions

Total Unburned Hydrocarbons -93% -30%

Carbon Monoxide -50% -20%

Particulate Matter -30% -22%

NOx +13% +2%

Non-Regulated Emissions

Sulphates -100% -20%*

Polycyclic Aromatic Hydrocarbons

(PAH)**

-80% -13%

NPAH (Nitrated PAHs)** -90% -50%***

Ozone Potential of Speciated HC -50% -10%

Life-Cycle Emissions

Carbon Dioxide (LCA) -80%

Sulphur Dioxide (LCA) -100%

*Estimated from B100 results. **Average reduction across all compounds measured.

***2-nitroflourine results were within test method variability.

Source:-www.epa.gov/otaq/models/analysis/biodsl/po2001.pdf, U.S. EPA (2001)

Graph:-1 Impact of biodiesel

Average emission impacts of biodiesel compared with fossil diesel

Source: EERE (2006)

Opinion regarding emissions of nitrogen dioxides varies from one study to

another study. Some fleet tests concluded Nox emissions to have increased with the use


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of biodiesel as fuel while other studies proved that emissions of Nox can be controlled,

if not decreased, by adjustments like retarding the injection timing or by adding heavy

alkylate replacing 20% of the fuel of B20% blend biodiesel. Average emission impacts of

biodiesel for heavy-duty highway engines are as given in Graph1.

1.5.3 Lubricity of Biodiesel

Biodiesel blends offer superior lubricating properties which may reduce engine

wear and extend the life of fuel injection systems. Tests with two leading lubricity

measuring systems the BOCLE machine and the HFRR machine have shown that

biodiesel blends offer better lubricating properties then conventional petroleum diesel.

The result of a lubricity test done by Exxon with petro diesel and biodiesel blends is

given in Table 4.

Table 4:- Lubricity test performance with different blends of petro diesel andbiodiesel in machine

Fuel Type Scar Friction Film %

Conventional low sulphur diesel 492 0.24 32

Blend (80% petro diesel + 20% biodiesel) 193 0.13 93

Blend (70% petro diesel + 30% biodiesel) 206 0.13 93

Petro diesel + 1000 ppm lubricity additive 192 0.13 82

Petro diesel + 500 ppm lubricity additive 215 0.14 94Petro diesel + 300 ppm lubricity additive 188 0.13 93

Source: Exxon & Interchem Environmental Inc. Lubricity Results (HFRR Machine)

1.6 Biodiesel Specifications

The key components that determine the quality of biodiesel are monoalkyl

esters, water & sediment, kinematic viscosity, ash copper strip corrosion, aromaticity

etc. Specification for B100 and a provisional specification for biodiesel and petro diesel

are also notified by the ASTM given in Table 5. Table 6 summarizes standards for

biodiesel in various countries and shows a comparison of selected properties of

biodiesel and petro diesel.


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Table 5:- Fuel properties for petro diesel and biodiesel

Property ASTM

Method

Petro diesel fuels Biodiesel

Flash Point D93 325 K min. 403 K min

Water & Sediment D2709 0.05 max. vol % 0.05 max. vol%

Kinematic Viscosity (40 C) D445 1.3-4.1 mm2/sec 1.9-6.0 mm

2/sec

Sulfated Ash D874 - 0.02 mass wt.%

Ash D5453 0.01 max. wt. % -

Sulfur D130 0.05 max wt. %. -

Sulfur D613 - 0.05 max wt.%

Copper Strip Corrosion D2500 NO 3 max NO 3 max

Cetane number D4530* 40 min. 47 min

Aromaticity D664 35 min vol %. -

Carbon Residue (100% Sample) D6584 -. 0.05 max mass %

Carbon D6584 0.35 max mass % -

Distillation Temperature (90%

Recovered)

D4951 555 K min-611 Kmax. -

*The carbon residue shall run out in the 100% sample.

Source: Demirbas A. (2007) Energy Policy

Table 6:- Biodiesel Standards of different countries

Specifications Units Australia France Germany Italy Sweden USA Draft EU

Standard/Specification ONC1191 - DINE

51606

UNI

10635

SS1

55436

ASTMD

6751

EN14214

Introduction Date Jly 1997 Spt1997 Spt1997 Apr1997 Nov1996 Dec2001 2001

Density @15 C g/cm3

0.85-0.89 0.87-.89 .875-

0.90

0.86-

0.90

0.87-

0.90

- 0.86-

0.90

Viscosity@40 C mm2/s 3.5-5.0 3.5-5.0 3.5-5.0 3.5-5.0 3.5-5.0 1.9-6.0 3.5-5.0

Flash Point 100 100 110 100 100 130 130

CFPP 0/-15 - 0-10/-

20

- -5 - 0/-15

Pour Point - -10 - 0/-15 - - -

Sulphur %max 0.02 0.02 0.01 0.01 0.01 0.05 0.01

CCR 100%max 0.05 - 0.05 - - 0.05 -10%disti.residue %max - 0.3 - 0.5 - - 0.3

Sulphated Ash %max 0.02 - 0.03 - - 0.02 0.01

(Oxid) Ash, mx %mass - - - 0.01 0.01 - -

Water max. mg/kg - 200 300 700 300 0.05 500

Total

Contaminants

mg/kg - - 20 - 20 - -


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Cu Corrosion 3h/50 - - 1 - - NO.3 1

Cetane No. 49 49 49 - 48 47 49

Neutral No. 0.8 0.5 0.5 0.5 0.6 0.8 0.02

Methanol %mass 0.20 0.01 0.3 0.02 0.02 - 0.02

Ester Content %mass - 96.5 - 98 98 - 96.5

Monoglyceride %mass - 0.8 0.8 0.8 0.8 - 0.8Diglyceride %mass - 0.2 0.4 0.2 0.1 - 0.20

Triglyceride %mass - 0.2 0.4 0.1 0.1 - 0.03

Free Glycerol %mass 0.02 0.02 0.02 0.05 0.02 0.02 0.25

Total Glycerol %mass 0.24 0.25 0.25 - - 0.24 115

Iodine No. 120 115 115 - 125 - -

C18:3 & higher

acids

15 - - - - - 10

Phosphorous ppm 20 10 10 10 10 10 10

Alkaline Matter (Na,K) - 5 5 10 10 - 360

Distillation 95% - 360 - - - 360 *IBP min. - - - - - *

Bound Glycerin - - - - - Max 0.8

Oxidation

Stability

Hrs. - - - - - 6 min.

Sediment - - - - - 0.05

Cloud Point - - - - * -

Source: - National renewable energy laboratory report (2002-04)

1.7 Toxicity of BiodieselImpacts on human health represent significant criteria as to the suitability of the

fuel for commercial applications. Health effects can be measured in terms of fuel

toxicity to the human body as well as health impacts due to exhaust emissions. Tests

conducted by various laboratories showed the acute oral toxicity of pure biodiesel fuel

as well as B20 in a single dose study on rats, and that biodiesel is not toxic and there is

no hazards anticipated from ingestion incidental to industrial exposure. According to

NIOSH (National Institute for Occupational Safety & Human Health), a 96-hr. lethalconcentration of biodiesel for bluegills was greater than 1000 mg/l and this aquatic

toxicity is deemed as insignificant. It is less than the irritation produced by 4% soap and

water solution.


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1.8 Sources / options for biofuel

India is one among largest petroleum consuming and importing countries. India

imports about 70% of its petroleum demand; petroleum imports is currently about

Rs.600 billion (about 30% of total import bill) compared to current trade deficit of about

Rs.500 billion. The currently yearly consumption of diesel in India is approximately 40

million tones forming 40% of the total petroleum products consumption. The ongoing

economic expansion would increase the demand for transportation fuel in short and

medium terms at high rates. According to international Energy Agency (IEA) scenario

developed for the USA and the EU indicate that near-term targets of up to 6%

displacement of petroleum fuels with biofuels appear feasible using conventional

biofuels. A 5% displacement of gasoline in the USA and 8% in EU requires about 5% of

available cropland to produce ethanol. A 5% displacement of diesel requires 13% of USA

cropland and 15 % in the EU, it is anticipated.

The dwindling fossil fuel sources and the increasing dependency on imported

crude oil have led to a major interest in expanding the use of bio-diesel. The recent

commitment by the USA government to increase bio-energy three fold in 10 years has

added impetus to the search for viable biofuels. The EU have also adopted a proposal

for a directive on the promotion of the use of bio-fuels with measures ensuring that bio-

fuels account for at least 2% of the market for gasoline and diesel sold as transport fuel

by the end of 2005.

Non-edible seeds like Jatropha, Pongamia and Neem etc. will be best options

as sources for feedstock for the oil and biofuel production in India. Detailed information

is required to use these sources for the biodiesel production and new technologies

regarding enhancement of use and production of biofuel need to be furnished

Justification of study

This study brings out the problems that lead and justify the feasibility ofJatropha

and non-edible oil to be utilized as fuel for the transport sector in India.


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This study includes collection and screening of high oil yielding varieties of J.

curcas. Cycle of biodiesel produced from non-edible oil by transesterification, analysis

mixed feedstock as a biodiesel has been investigated.

Comparison of J. curcas seeds oil with Pongamia and Neem seed oils has been

made in order to provide an estimate of their potentials as biodiesel; and engine

performance when mixed oils are used. The study would provide useful leads on

application ofJatropha curcas feedstock for biodiesel.

Objectives of the study

To screen germplasm of J. curcas for oil quantity and quality from

different provenances of India (Rajasthan and Uttaranchal).

To standardize the protocols to maximize oil yield.

To assess of physico-chemical properties of J. curcas and other non-

edible oils.

To develop protocols for esterification and purification so that the crude

oil can be improved for use as diesel substitute for stationary motors.

To evaluate application of biodiesel in stationary engines.

To evaluate and compare Neem oil, Pongamia oil with that ofJ. curcas oil

for developing the biodiesel from mixed feedstock.


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Chapter 2

Review of Literature

Feedstock for biodiesel

There is no single feedstock that can be used throughout the year and in all

regions of any country. Mixed feedstock is an option but demands change in process

and technology.

Many developed countries are using edible oil-seed crops such as soybean,

rapeseed, groundnut, sunflower for production of bio-diesel. However, developing

countries like India, who import huge quantities of edible oil to meet their

requirements, cannot afford to use edible oils for bio-diesel production. Many

alternatives plants have been identified as feedstock for bio-fuel; andJatropha curcas is

one of them. The genus Jatropha has 476 species which are distributed throughout the

world. Among them, 12 species are recorded from India. Jatropha curcas Linn. (Physic

nut or Ratanjot) belongs to family Euphorbiaceae. According to Dehgan & Webster

(1979) and Schultze-Motel (1986) the genus name Jatropha derives from the Greek

word jatros (doctor) and trophe (food), which implies its medicinal uses.This species is

native of tropical America, but is now found abundantly throughout the arid, semi-arid,

tropical and subtropical regions of the world (Makkar et al. 1997; Heller 1996). Jatropha

curcas Linn. is a deciduous shrub that grows up to a height of 35 m, and has a

productive life of 50 years. It bears fruits from the second year of its establishment and

the economic yield stabilizes from the fourth or fifth year onwards (Hikwa 1995;

Henning 1996; Makkar et al. 2001). In India, it is found in semi-wild conditions in the

vicinity of villages and is one of the most promising drought tolerant perennial plants

adapted to various soil conditions. It can tolerate drought conditions and animals do not

browse its leaves.

Major feedstock production areas region-wise:

Soybeans: Europe (Ukraine, Russia, Italy, France and Rest of Europe); North

America (USA, Canada); Latin America (Argentina, Brazil); Asia-Pacific (China, India,


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Indonesia, Korea, Japan, Thailand and Rest of Asia-Pacific). Feedstock used for

biodiesel: Only Europe and North America.

Cotton Seeds: Europe (Greece, Spain); USA; Latin America (Brazil, Argentina);

Asia-Pacific (China, India, Pakistan, Australia and Rest of Asia-Pacific). Feedstock used

for biodiesel: Only Europe and North America.

Rapeseeds: Europe (Germany, France, United Kingdom, Poland, Czech Republic,

Denmark, Slovakia, Sweden, Austria and Rest of Europe); North America (USA, Canada);

Asia-Pacific (China, India, Australia, Pakistan and Bangladesh). Feedstock used for

biodiesel: Only Europe and North America

Groundnuts: USA; Asia-Pacific (China, India, Indonesia, Thailand and Pakistan);

Latin America (Brazil, Argentina).

Sunflower Seeds: Europe (France, Hungary, Spain, Italy, Slovakia, Russia and Rest

of Europe); North America (USA, Canada); Latin America; Asia-Pacific (China, India,

Pakistan and Australia).

Palm Kernel: Latin America (Brazil, Colombia); Asia-Pacific (Indonesia, Malaysia

and Thailand). Feedstock used for biodiesel: Malaysia, Indonesia

Copra: Asia-Pacific (Indonesia, India and Thailand) and Rest of World.

Castor Seeds: Brazil; Asia-Pacific (India, China and Thailand).

Jatropha Curcas: India, Africa, Malaysia, Indonesia. Feedstock used for biodiesel:

India, Pakistan, Africa.

In India Jatropha curcas has been accepted as a major feedstock other than

Pongamia pinnata and other non-edible vegetable oils. However, the west and other

countries are still dependent upon vegetable oil as a source of biodiesel. According to

Agarwal (2007) biodiesel can be blended in any proportion with mineral diesel to create

a biodiesel blend or can also be used as neat. According to him the main resources for

biodiesel production are non-edible oils obtained from Jatropha curcas (Ratanjyot),


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Pongamia pinnata (Karanj), Calophyllum inophyllum (Nagchampa), and Hevea

brasiliensis (Rubber plant).

Two plant species, Sapindus mukorossi and Jatropha curcas were discussed as

newer sources of oil for biodiesel production by Chhetri et al (2008). Experimental

analysis conducted by them showed that both oils have great potential to be used as

feedstock for biodiesel production.

Jatropha is a fast growing and long lived plant, easy to propagate, found to be

growing in many parts of the country. It can grow and survive with minimum inputs in

marginal land and not browsed by animals and seeds not even eaten by away by birds.

The organic matter from shed leaves enhances earthworm activity in the soil around the

root zone of the plants, which improve the fertility of diesel has important implications

for meeting the demands of rural energy services and also exploring practical

substitutes for fossil fuels to counter greenhouse gas accumulation in the atmosphere

(Parida & Eganathan, 2007).

Studies for the synthesis and characterization of biodiesel from non-edible oils

like Jatropha curcas, Pongamia glabra (Karanj), Madhucaindica (Mahua) and Salvadora

oleoides (Pilu) have been carried out at our laboratory at the National Botanical

Research Institute. The seeds of Madhuca indica (Mahua) produce oil that can be

converted to biodiesel by transesterification. The cake left after extraction of oil can be

used as a fertilizer (Behl et al., 2007). Pongamia pinnata oil has multiple uses. It is a very

good source of vegetable oil that can be converted to biodiesel and meet diesel

requirement of the country. Biodiesel made from Karanj oil has been evaluated for its

efficacy by National Botanical Research Institute and IIP, Dehradun (Behl et al., 2007).

The seeds ofSalvadora oleoides are rich in oil. The oil extracted from the seeds

can serve as a local (Rajasthan and Gujarat) resource that can be used as feedstock for

biodiesel in desert areas. The seeds are rich in oil and contain Lauric, myristic, and

palmitic acids (Behl et al. 2007).


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Huber et al (2007) reported that the yield of straight chain alkanes increases

when sunflower oil is mixed with vegetable oil. They illustrated that dilution of heavy

vacuum oil (HVO) can improve the reaction chemistry. According to them mixing of

sunflower oil with heavy vacuum oil does not decrease the rate of desulfurization

indicating that sunflower oil does not inhibit the hydro treating of heavy vacuum oil.

Packages process for the cultivation, seed processing for oil extraction and

the production of the methyl esters from J. curcas oil was described by Foidl et al

(1996).

Agarwal (2007) reviewed production, characterization, current status of

vegetable oil and biodiesel from well-to-wheel including greenhouse gas emissions,

well-to-wheel efficiencies, fuel versatility, infrastructure, availability, economics, engine

performance emissions, effect on wear and lubricating oil etc. He reported that ethanol

is an attractive alternative fuel because it is a renewable bio-based resource and it is

oxygenated, thereby providing a potential to reduce particulate emissions in

compression-ignition engines. In this review, he also reported properties and

specifications of ethanol blended with diesel and gasoline fuel. Effect of the fuel on

engine performance and emissions (SI as well as compression ignition (CI) engines) and

material compatibility were also studied. According to his study biodiesel from Jatropha

curcas (Ratanjyot), Pongamia pinnata (Karanj), Calophyllum inophyllum (Nagchampa),

Hevea brasiliensis (Rubber) etc. oil can be blended in any proportion with mineral diesel

to create a biodiesel blend or can be used in its pure form. Biodiesel in compression

ignition (diesel) engine requires very little or no engine modifications.

Jatropha curcas

Jatropha curcas is a land race in India and occurs in several states and agroclimatic conditions. Screening for variability can help in genetic selection and

improvement of stocks. Several investigators have collected and evaluated Jatropha

curcas accessions and other non-edible oilseeds from India and abroad for use as

biodiesel feedstock.


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Germplasm evaluation

Kaushik et al (2007) studied genetic variability in seed traits of 24 accessions ofJ.

curcas collected from Haryana. Seeds of collected accessions were accessed for oil

content and reported a range between 28 to 38 %. They reported a higher genotypic

coefficient of variation as compared to phenotypic, indicating the predominant role of

environment. They also found seed weight to have positive correlation with seed length,

breadth, thickness and oil content. On the basis of their research, it was suggested that

the crossing between accessions will result in wide spectrum in the form of cluster for

variability in subsequent generations.

Nambisan (2007) undertook genetic analysis of Jatropha species for yield

characteristics in order to identify quantitative trait loci (QTLs) and improving useful

characters of gene inherited in a multigenic fashion for the yield of oil. She standardized

and applied RAPD and AFLP to detect the variations at DNA level rather than the

phenotypes.

A systematic collection of 162 accessions of J. curcas was carried out from four

distinct eco-geographic zones of peninsular India in 2005 along with passport data,

documentation of important plant traits in-situ, eco-geographic parameters studies by

Sunil et al (2007). Assessment of variability among the collected accessions was also

undertaken by them.

Morphological characteristics of selected germplasm seeds

Morphological and physico-chemical studies of oil of non-edible oilseeds can be

helpful to screen out the best germplasm for the oil yield and oil components.

Parkiabiglobbossa and Jatrophacurcas seeds were analyzed by Akintayo (2004)

for their proximate composition like oil extraction, physic-chemical characteristics, fatty

acid composition, lipid classes and sterols of extracted oil. Proximate composition

analysis revealed that percentage of crude protein; crude fat and moisture in Parkia

biglobbossa were 32.4%, 26.52%, 10.18% while in J. curcas, it was 24.6%, 47.25%,

5.54%. Campesterol, stigmasterol, b-sitosterol, D5-avenasterol and D7-stigmasterol


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were identified in P. biglobbossa seed oils, however b-sitosterol was found most

abundant, constituting 71.9% in J. curcas and 39.5% in P. biglobbossa. Fatty acid

composition was analyzed for P.biglobbossa and J.curcas oil. J. curcas oil had 72.7%

unsaturated fatty acids with oleic acid; and P.biglobbossa had 62% unsaturated fatty

acids with linoleic acid, being the most abundant. Lipid classification showed triglyceride

as the dominant lipid species in the seed oils. Physico-chemical analysis of the oils

showed that the oil extracted from P.biglobbossa and J.curcas are applicable for resin

and soap manufacture.

Visvanathan et al (1996) determined physical properties of Neem seed such as

dimensions, crushing strength, 1000 nut mass, relative mass of kernel and shell, angle of

repose, porosity, bulk density, particle density and coefficient of static friction. They

reported Neem seed moisture ranged from 76% to 21%, stem-end diameter ranged

from 1287 to 1620 mm. The crushing strength of the nut was measured along the

longitudinal axis and a diametric axis which decreased with increase in moisture

content; mass of 1000 nuts, percent content of the mass of the kernel and the angle of

repose of Neem nut was found to increase with increase in moisture content; the

porosity, bulk density, particle density decreased linearly as the moisture content

increased; and coefficient of static friction on various surfaces increased with increase in

moisture content.

Oil extraction

Use of appropriate oil extraction processes and extraction solvents is very

important factor to be followed in extraction of non-edible oil.

Many petroleum and non-petroleum solvents have been used to extract oil from

oil seeds. Hydrocarbon solvents (hexane, heptane and pentane) were used for thestandardization of solvent for high oil yield. Usually n-hexane was used as it is free from

the nitrogen, sulphur, unsaturated compounds and found sufficiently stable to be used

indefinitely. Adriaans (2005) observed that commercial heptane might be preferred for

the extraction of castor oil which is not freely miscible with hydrocarbons except at


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elevated temperature. As a result only water has been found applicable as a solvent for

the extraction of oil from palm, olive and coconut. 1:2 ratio of hexane-water mixture

were found economical only in the processing of olive oil with high potential for future

use. Use of hexane for the extraction of oil from the oilseeds has been suggested and

found economically feasible.

Liauw et al (2008) studied Neem oil extraction using different solvents to

increase the oil yield. Maximum 44.29% oil yield was reported using n-hexane while

41.11% oil was extracted when ethanol at 50C was used. After the extraction, the effect

of solvents in physico-chemical characteristics of oil was also studied by them.

Hexane and isopropanol were compared as solvents for use in ambient-

temperature equilibrium extraction of rice bran oil by Procter and Bowen (1996). 20 ml

of isopropanol solvent was found as effective to extract the oil from 2 g of bran as

compared to hexane. Free fatty acid level was found between 2-3% in both the solvents.

Large-scale production of oil was done by using 30 g of bran in 150 ml of solvent which

had similar free fatty acid content and a phosphorus level of approximately 500 ppm. It

was observed that the oil extracted with isopropanol was significantly more stable to

heat-induced oxidation than hexane.

Isopropanol was significantly more stable to heat-induced oxidation than hexane

and antioxidants that are more easily extracted by isopropanol than hexane may be

responsible for the increase in stability of oil as reported by Procter and Bowen (1996)

during their study on extraction of oil from rice bran oil.

Shah et al (2005) studied extraction of oil from Jatropha seeds by enzymatic

reaction. They treated the seeds using ultra sonication method and found that oil

extraction procedure was easier and took less time for extraction.

Mechanical press and solvent extraction methods for oil extraction were studied

by Adriaans (2005) for various oil seeds. It was observed that in a pre-press solvent

extraction the press was operated to give a pressed cake with 15 18% oil. The expeller

and solvent method for proper extraction of oil was modified to extract oil from the


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cake with a solvent which offers a way to reduce the loss of oil content to less than 1%

in pressed cake.

Oil content of 162 accessions of J. curcas was estimated by Sunil et al (2007)

using Soxhlet extraction method. It ranged from 22% to 42%. They reported multi

location evaluation using an in-situ method developed to facilitate the selection of

promising accessions and for the identification of superior lines by assessing the

phenotypic traits of plants.

Protocol for the esterification of Karanj oil was developed by Raheman and

Phadatare (2004) which consist of heating of oil, addition of KOH and methyl alcohol,

stirring of mixture, separation of glycerol, washing with distilled water and heating for

removal of water.

Physicochemical properties of oil & biodiesel

Physico-chemical properties are crucial since these will govern quality and

process of trans esterification as well as performance of the blend. These parameters

can directly influence the quality of oil. Physico-chemical properties of fatty acid methyl

ester of non-edible seed oils like Azadirachta indica, Calophyllum inophyllum, Jatropha

curcas and Pongamia pinnata were found most suitable for biodiesel and match majorspecification of biodiesel.

Physico-chemical properties of non-edible seed oils like Azadirachta indica,

Calophyllum inophyllum, Jatropha curcas and Pongamia pinnata were found most

suitable for biodiesel and match specification of biodiesel as per USA, Germany and

European standards (Azam et al, 2005). They concluded that these plants have great

potential for biodiesel production.

Soapnut oil was reported (Chhetri et al, 2008) to have an average of 9.1% free

FA, 84.43% triglycerides, 4.88% sterol and 1.59% others. Jatropha oil contains

approximately 14% free FA, approximately 5% higher than Sapindus mukorossi (soap

nut) oil. Soapnut oil biodiesel contains approximately 85% unsaturated FA while

Jatropha biodiesel was found to have approximately 80% unsaturated FA. Oleic acid was


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found to be the dominant FA in both Soapnut and Jatropha biodiesel. Over 97%

conversion to FAME was achieved for both Soapnut and Jatropha oil.

Kaul et al (2007) studied the synthesis and characterization of biodiesel from

non-edible oils like Jatropha curcas, Pongamia glabra, Madhuca indica and Salvadora

oleoides.

The density and viscosity of the Polanga oil methyl ester formed after triple

stage trans esterification were found to be close to those of petroleum diesel oil. The

flash point of all the blends ofPongamia or polanga oil methyl ester was found higher

than that of diesel oil. Based on the exhaustive engine tests undertaken by Sahoo et al

(2007), it was concluded that polanga based biodiesel can be adopted as an alternative

fuel for the existing conventional diesel engines without any major modifications in the

engine system. Particularly, 100% biodiesel showed higher flash point than petroleum

diesel oil. All these tests for characterization of biodiesel demonstrated that almost all

the important properties of biodiesel were in very close agreement with the diesel oil

making it a potential fuel for the application in compression ignition engines for

complete replacement of diesel fuel.

Physico-chemical properties of oil and fatty acid methyl ester of non-edible seed

oil like Azadirachta indica, Calophyllum inophyllum, Jatropha curcas and Pongamia

pinnata were found most suitable for biodiesel which matches the major specification of

biodiesel with USA, Germany and European standards. Physico-chemical properties like

specific gravity, acid value, free fatty acids content, refractive index etc. of oil and

biodiesel have been determined and analyzed using Bureau of Indian standards BIS: 548

(1976).

Gerpen et al (2002, 2004) analyzed the basics of biodiesel production by basic

pilot plant as equipment and biodiesel plant logistics. They studied long term storage of

biodiesel and physico-chemical properties after extraction of oil of soybean. They

carried out studies on different methods of fuel property measurement, soap catalyst


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measurement, fatty acids and total glycerol measurements and analyzed for the

physiochemical properties as per ASTM specification.

A central composite rotatable design was prepared to study the effect of

methanol quantity, acid concentration and reaction time on the reduction of free fatty

acids content of Mahua oil during its pretreatment for making biodiesel by Ghadge and

Raheman (2006). According to them, all the three variables significantly affected the

acid value of the product; methanol being the most effective followed the reaction time

and acid catalyst concentration.

Important fuel properties of methyl esters of Pongamia oil (Biodiesel) were

compared for the physico-chemical properties like (viscosity = 4.8 Cst @ 40C and flash

point = 150C) with ASTM and German biodiesel standards and were found good

compatibility as commercial diesel as reported by Karmee and Chadha (2005). Physico-

chemical properties of the Karanj methyl ester after esterification were found to be very

close to petroleum diesel oil by Srivastava and Verma (2007).

Study were undertaken by Sarathy et al (2007) on the detailed effect of the

FAME molecular structure on the saturated (i.e., methyl butanoate) and an unsaturated

(i.e., methyl crotonate) combustion chemistry. They studied that the C 4 FAME was

oxidized in an opposed flow diffusion flame and a jet stirred reactor. Consistent trends

were seen in both the experiments. Both fuels had similar reactivity. As a result it was

observed that methyl crotonate combustion produces much higher levels of C2H2, 1-

C3H4, 1-C4H8 and 1,3-C4H6, benzene in the opposed flow diffusion flames and 2-propenal,

methanol and acetaldehyde than methyl butanoate. The methyl butanoate combustion

had higher levels of C2H4 while for methyl crotonate it was not detected.

According to the Liauw et al (2008) extraction of Neem oil using hexane and

ethanol as a solvent was effective for physico-chemical properties of the oil. They

studied kinetic reactions which indicated that extraction process was endodermic,

irreversible and spontaneous. As a result they observed that increase in temperature


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during extraction increased oil yield, saponification value and peroxide value but

decreased the iodine value and the oil quality.

Nambisan (2007) reported Pongamia oil has higher quantity of unsaponifiable

matter than Jatropha oil while the acid value was similar for both. Presence of high

unsaponifiable matter in Pongamia inhibited its processing for biodiesel production.

Nambisan (2007) reported that the energy rating of J. curcas is comparatively low (40

MJ/kg) as compared to other species of Jatropha e.g. J. glandulifera (57.1MJ/kg), which

is a reason for low oil yield in J. curcas; however crossing these two species may result in

plants with higher oil and energy content.

Toxicity in non-edible oil

Biologically active substances such as phorbol esters (a family of compounds

known to cause a large number of biological effects such as tumor promotion and

inflammation) are responsible for the toxicity of J. curcas oil.These are responsible for

degradation of quality of oil non-edible oil seed cake. Reports related to toxicity in

detoxification are a major issue for use of cake as an animal feed.

Phorbol esters were isolated and their molluscidal, insecticidal, fungicidal

properties were analyzed in lab-scale experiments as well as in field trials by Gubitz et al(1999). Biotechnological processes for exploitation ofJ. curcas have been developed by

them that include genetic improvement of the plant, biological pest control, enzyme-

supported oil extraction, anaerobic fermentation of the press cake, isolation of anti-

inflammatory substances and wound-healing enzymes.

Haas and Mittelbach (2000) studied the toxic agent as well as technical

restriction due to detoxification of seed oil ofJ. curcas plant. They reported that seed oil

ofJatropha curcas contains phorbol esters and it was necessary to find feasible routes

for detoxification of this oil. The same was done by treating the oil for refining process.

Several refining steps were optimized for detoxification. Almost no effect was observed

with degumming and deodorization whereas de-acidification and bleaching reduced the

phorbol esters content by 55%.


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Shelf life of oil and biodiesel

Biodiesel as well as oils have a shelf life and cannot be stored for too long for

various reasons. Oils do have tocopherols that provide stability to some extent yet they

are prone to degradation. Various factors may effects the quality of oil and can degrade

the oil during storage. There have been several studies on shelf life of vegetable oils and

bio diesel.

Bouaid et al (2007) conducted 30-months study on high oleic sunflower oil

methyl ester (HOSME), high-erucic Brassica oil (HEBO) ME, low-erucic Brassica oil (LEBO)

ME and used frying oil (UFO) ME and found that all biodiesel samples were very stable

because they do not have rapid increase in peroxide value (PV), acid value (AV), viscosity

(), and insoluble impurities (II). However, there was a deterioration of the fuel after 12

months of storage. Significant differences were found in the value of the measured

parameters for all fuel type and storage conditions with the passage of time. For all

biodiesel samples, peroxide, acid value, viscosity, and insoluble impurities tended to

increase and iodine value (IV) decreased over time. Fuels exposed to daylight tended to

degrade at faster rate than did the others fuels, particularly as indicated by their

peroxide and acid values. The specification limit of the parameters studied exceeded in

biodiesel samples after a storage time of 12 months as reported by them.

Presence of fully converted monoalkyl esters is the major requirement in quality

biodiesel (Fernando, 2007). There is a high propensity of substandard biodiesel entering

the market and being used in compression ignition engines due to high associated costs

of testing and widespread production of biodiesel. It is important to understand how

low grade biodiesel with a lower methyl ester conversion affects the parameters of

quality standards, he reported, since this effects engine performance and durability.

Performance of fatty acid methyl esters with different proportions of unconverted

triglycerides has been evaluated by Fernando (2007). The study comprehensively

evaluated effect of unconverted triglycerides on flash point, water, sediment, kinematic

viscosity, sulfur content, sulfated ash, copper strip corrosion, cetane number, cloud


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point, carbon residue, acid number, free glycerin, total glycerin, phosphorus content

and distillation temperature.

One of the major technical issues facing biodiesel is its susceptibility to oxidation

upon exposure to oxygen in ambient air. This susceptibility is due to its content of

unsaturated fatty acid chains, especially those with bis-allylic methylene moieties.

Oxidation of fatty acid chains was complex process that proceeds by a variety of

mechanisms. Besides the presence of air and various other factors influence the

oxidation process of biodiesel including presence of light, elevated temperature,

extraneous materials such as metals which may be even present in the container

material, peroxides, antioxidants as well as the size of the surface area between

biodiesel and air.

Gupta et al (2008) extracted oil from rice bran, Jatropha curcas and Karanj oil

and extracted oils were stored for one year to find out change in the quality during

storage. Physico-chemical properties like viscosity, free fatty acid content and density

were monitored. All the three parameters showed an increasing trend during the

storage period. This trend was observed in washed as well as unwashed bio-diesel of all

the three oils.

Addition of antioxidants or modification of the fatty ester profile is a common

approach to improve biodiesel oxidative stability. Knothe (2007) suggested factors that

influence biodiesel oxidative stability.

Leung et al (2006) investigated biodiesel degradation characteristics under

different storage conditions. Quality of twelve biodiesel samples, which were divided

into 3 groups, stored at different temperatures and environmental conditions were

monitored at regular interval over a period of 52 weeks. Experimental results

demonstrated that the biodiesel under test degraded less than 10% within 52 weeks for

those samples which were stored at 4 and 20 C while nearly 40% degradation was

found for those samples stored at a higher temperature, i.e. 40C. The results suggested


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that high temperature together with air exposure, water content (due to hydrolysis)

greatly increases the biodiesel degradation rate.

Comparative study of crude oil, filtered oil and refined oil was reported by Mittal

et al (1964) who described the method of refining oil with Boume solution for

vegetative and industrial oil as per the FFA content following baileys method.

Conversion of vegetable oil to biodiesel

Trans-esterification is a process to convert oil to biodiesel. During conversion

various factors have to be identified that influence the yield and the properties of

biodiesel. Studies of relevant factors for biodiesel conversion have been undertaken

extensively.

Palm kernel oil has been identified as a renewable resource for biodiesel. The

effect of ethanolPKO ratio on (PKO) biodiesel yield was studied by Alamu et al (2007)

with a view to obtain optimal feedstock ratio. Experiments were conducted for ethanol

PKO ratios 0.1, 0.125, 0.15, 0.175, 0.2, 0.225 and 0.25 at trans esterification conditions

at 60C temperature for 120 min reaction time in 1.0% KOH catalyst concentration.

29.5%, 54%, 75%, 89%, 96%, 93.5% and 87.2% average PKO biodiesel yields were

obtained for the respective feedstock ratios. This showed the increase in biodiesel yieldwith ethanolPKO ratio up to 0.2 in trans esterification reaction. Biodiesel as a fuel was

found within the biodiesel standard specifications.

Berchmans and Hirata (2007) developed a technique to produce biodiesel from

crude J. curcas oil having high free fatty acids (15% FFA) by trans esterification using acid

and alkali treatments. High FFA level of J. curcas oil was reduced to less than 1% by a

two-step pretreatment process. In the first step, reaction was carried out with 0.60 w/w

methanol-to-oil ratios in the presence of 1% w/w H2SO4 as an acid catalyst for 1h

reaction at 50C. In the second step, trans esterification was done by using 0.24 w/w

methanol to oil and 1.4% w/w NaOH as alkaline catalyst to oil at 65C. After the reaction

was over, the mixture was allowed to settle for 2 h and the methanolwater mixture

was separated and top layer of methyl ester was removed resulting in a 90% yield.


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The kinetics of the esterification of free fatty acids (FFA) in sunflower oil with

methanol in the presence of sulphuric acid at concentrations of 5 and 10 wt.% relative

to free acids as catalyst and methanol/oleic acid mole ratios from 10:1 to 80:1 was

studied by Berrios et al (2007). Experimental results showed that a first-order kinetic law

was fit for the forward reaction and a second-order for the reverse reaction. The

influence of temperature on the kinetic constants was determined by fitting the results

to the Arrhenius equation. The energy of activation for the forward reaction decreased

with increasing catalyst concentration from 50.745 to 44.559 J/mol. Based on the

results, a methanol/oleic acid mole ratio of 60:1, a catalyst (sulphuric acid)

concentration of 5 wt. % and a temperature of 60C provided a final acid value of the

biodiesel lower than 1 mg KOH/g oil within 120 min. and this was a widely endorsed

limit for efficient separation of glycerin and biodiesel during production.

Cvengros and Cvengrosova (2004) have used frying oils or fats (UFO) for the

production of methyl esters (ME) of higher fatty acids as alternative fuels for diesel

engines. They were targeting quality with an acidity number up to 3 mg KOH/g and

water content up to 0:1 wt.% after treatment. They reported that vacuum distillation

evaporator was an effective method for reducing free fatty acids which simultaneously

decreased the content of FFA and water in UFO. Final distillation of raw methyl ester in

an 8ml vacuum evaporator resulted in practically all parameters required by the

standard. Undesirable low-temperature properties of methyl ester derived from UFO

due to higher fraction of saturated acyls could be adjusted by the addition of

depressants.

Demirbas (2009) studied the trans esterification process of vegetable oils in

supercritical methanol without using any catalyst. He found that the most important

variables that may effects methyl ester yield during the trans esterification reaction

were molar ratio of alcohol and the reaction temperature to vegetable oil. Supercritical

methanol has a high potential for both transesterification of triglycerides and methyl

esterification of free fatty acids to methyl ester production for the diesel fuel substitute.


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He et al (2007) developed a system for continuous transesterification of

vegetable oil using supercritical methanol by using a tube reactor. They observed

increase in the proportion of methanol; reaction pressure and reaction temperature can

enhance the production yield effectively. However, side reactions of unsaturated fatty

acid methyl esters (FAME) occurred when the reaction temperature was found over

300C, which lead to much loss of material. There was also a critical value of residence

time at high reaction temperature and the production yield got decreased. The optimal

reaction condition under constant reaction temperature process was 40:1 of the molar

ratio of alcohol to oil, 25 min of residence time, 35 MPa and 310C. Maximum yield of

77% was found in the optimal reaction conditions.

The kinetics in hydrolysis and subsequent methyl esterification was studied by

Minami and Saka (2006) to elucidate reaction mechanism. Fatty acid composition was

found to act as acid catalyst and simple mathematical models were proposed in which

regression curves were fit well with experimental results. Fatty acid was thus concluded

to play an important role in the two-step supercritical methanol process.

Biodiesel was synthesized enzymatically with Novozym-435 lipase in presence of

supercritical carbon dioxide by Rathore and Madras (2007). Effect of reaction variables

such as temperature, molar ratio, enzyme loading and kinetics of the reaction was

investigated for enzymatic synthesis in supercritical carbon dioxide at 200 to 400C. As a

result very high conversions (>80%) were obtained within 10 minutes and nearly

complete conversions were obtained at within 40 min. However, conversions of only

6070% were obtained in the enzymatic synthesis even after 8 h were observed.

The conversion process of oil to biodiesel by three types of reaction like trans

esterification, hydrolysis of triglycerides and methyl esterification studied by Susiana

and Saka (2004) for the conversion of water containing vegetable oil proceeded

simultaneously by free supercritical methanol as a catalyst to produce high yield and to

see the effect of water on the yield of methyl esters during conversion process. They

observed that the presence of free fatty acids and water always produced negative

effects which may cause soap formation, consumed catalyst and reduced catalyst


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effectiveness, all of which resulted in a low conversion. They found that presence of

water at a certain amount could enhance the methyl esters formation. These results

were compared with those of methyl esters prepared by acid and alkaline catalyzed

methods which were found that supercritical methanol, crude vegetable oil as well as its

wastes could be readily used for biodiesel fuel production in a simple preparation.

Gerpen (2005) found conventional processing of oil to biodiesel involving an

alkali catalyzed process unsatisfactory for its cost; high free fatty acid feedstock and

soap formation. He showed that pretreatment processes using strong acid catalysts

provided good conversion yields and high-quality final products. These techniques have

been extended to allow biodiesel production from feedstocks like soap stock that are

often considered to be waste.

Optimum combinations for reducing the acid level of Mahua oil to less than 1%

after pretreatment was 0.32 v/v methanol-to-oil ratio, 1.24% v/v H2SO4 catalyst and 1.26

h reaction time at 60 C as observed by Ghadge and Raheman (2006). After the

pretreatment of Mahua oil, trans esterification reaction was carried out with 0.25 v/v

methanol-to-oil ratio (6:1 molar ratio) and 0.7% w/v KOH as an alkaline catalyst to

produce biodiesel. Properties of biodiesel prepared from Mahua were analyzed and

matched to the requirements of both the American and European standards.

Five flow sheet options have been reported by Harding et al (2007) in their study

to investigate the alkali and enzyme catalyzed production routes from rapeseed oil, use

of methanol or ethanol for transesterification and the effect of efficiency of alcohol

recovery. They concluded that the enzymatic production route was environmentally

more favorable. Acidification, and photochemical oxidation were reduced by 5% with

considerable benefit on global warming. Certain toxicity levels have been reduced to

more than half. These results were achieved mainly due to lower steam requirements

for heating in the biological process.

He et al (2007) proposed a new technology of gradual heating that can

effectively reduce the loss caused by the side reactions of unsaturated FAME at high


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reaction temperature with the new reaction technology; the methyl esters yield was

found to be more than 96%.

Cooking oil was mixed with canolaoil at various ratios in order to make use of

used cooking oil for production of economical biodiesel by Issariyakul et al (2007).

Methyl and ethyl esters were prepared by KOH-catalyzed trans esterification from the

mixtures of both the oils. Water content, acid value and viscosity of esters after

conversion to biodiesel met ASTM standard except for ethyl esters prepared from used

cooking oil. Although ethanolysis was proved to be more challenging, ethyl esters

showed reduction in the crystallization temperature (45.0 to 54.4C) as compared to

methyl esters (35.3 to 43.0 C).

Karmee and Chadha (2005) prepared biodiesel from non-edible oil ofPongamia

pinnata by trans esterification of the crude oil using in methanol in the presence of KOH

as catalyst. As a result maximum conversion of 92% (oil to ester) was achieved using a

1:10 molar ratio of oil to methanol at 60C. Tetrahydrofuran (THF) was used as a co-

solvent which increased the conversion to 95%. Solid acid catalysts viz. Hb-Zeolite,

montmorillonite K-10 and ZnO were also used for transesterification.

Morin et al (2007) studied heteropolyacids (HPA) with kegging structure and

evaluated homogeneous brinstead acid catalysts in the reaction of rapeseed oil trans

esterification with methanol and ethanol at 358 K atmospheric pressure. Rapeseedoil

trans esterification with ethanol over anhydrous keggin HPAs lead to higher conversion

level than H2SO4 compared at equivalent H+ concentration and H2O/H+ molar ratio. This

demonstrated the advantages of strong brinstead acids in vegetable oil

transesterification with ethanol in mild conditions. The proton solvation with water

molecule was shown to be a crucial parameter then Mo samples exhibited higher

activities due to their ability to lose crystallization water at lower temperatures

compared to samples. It was observed that higher trans esterification rates were

obtained with ethanol than methanol in presence of HPA.


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Nabi et al (2006) converted non-edible Neem oil to biodiesel by trans

esterification and investigated the combustion, exhaust emissions of transesterified

biodiesel-diesel blends with neat diesel fuel.

Production of biodiesel from edible oils like palm and groundnut oil as well as

non-edible oils like Pongamia pinnata and Jatropha curcas was investigated by Rathore

and Madras (2007). They reported that variables affecting the conversion during

transesterification are molar ratio of alcohol to oil, temperature and time. They also

investigated use of supercritical methanol and ethanol without using any catalyst.

Sahoo et al (2007) have standardized method for the extraction of Polanga

(Calophyllum inophyllum L.) seed oil, conversion of oil to biodiesel along with the testing

of physico-chemical and mechanical properties. It was observed that the viscosity of

vegetable oil get reduced substantially after transesterification. The density and

viscosity of the Polanga oil methyl ester formed after triple stage transesterification

were found to be close to those of petroleum diesel oil. The flash point of all the blends

ofPongamia or Polanga oil methyl ester was found higher than that of diesel oil.

Based on the exhaustive engine tests undertaken by Sahoo et al (2007), it was

concluded that Polanga based biodiesel can be adopted as an alternative fuel for the

existing conventional diesel engines without any major modifications in the engine

system. Particularly, 100% biodiesel showed higher flash point than petroleum diesel oil.

All these tests for characterization of biodiesel demonstrated that almost all the

important properties of biodiesel were in very close agreement with the diesel oil

making it a potential fuel for the application in compression ignition engines for

complete replacement of diesel fuel.

Sunflower oil methanolysis was undertaken by Stamenkovic et al (2007) in a

stirred reactor at different agitation speeds. Measurements of drop size, drop size

distribution and the degree conversion demonstrated the effects of the agitation speed

in both non-reaction (methanol/sunflower oil) and reaction (methanol/KOH/sunflower

oil) systems.


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Talens et al (2007) attempted to decrease the consumption of materials, energy

and promote the use of renewable resources. They suggested use of Energy Flow

Analysis (ExFA) as an environmental assessment tool and applied to the process of

biodiesel production to account wastes, emissions, exergetic efficiency, compare

substitutes and other types of energy sources. As a result they showed that the

production process had a low energy loss (492 MJ). The energy loss was reduced by

using potassium hydroxide/sulphuric acid as process catalysts and it was observed that

loss during biodiesel production can be further minimized by improving the quality of

the used cooking oil.

Factors effecting trans-esterification

Studies have been carried out by Marchetti et al (2007) using different oils as

raw material, different alcohol (methanol, ethanol, butanol) as well as different catalysts

such as sodium hydroxide, potassium hydroxide, sulfuric acid and supercritical fluids and

heterogeneous ones such as lipases enzymes. They evaluated the advantages,

disadvantages and kinetics of reaction.

Meher et al (2006) studied transesterification of Karanj oil in methanol for

production of biodiesel. The reaction parameters such as catalyst concentration,

alcohol/oil molar ratio, temperature and rate of mixing were optimized for production

of Karanjoil methyl ester. Fatty acid methyl esters content in the reaction mixture were

quantified by HPLC and 1H NMR. The yield of methyl esters from Karanj oil under the

optimal condition was 9798%.

Ngamcharussrivichai et al (2007) studied the heterogeneously catalyzed trans

esterification of palm kernel oil with methanol over various modified dolomites at 60C.

The modification of dolomite was performed via a conventional precipitation methodusing various nitrate salt solutions of alkali earth metals and trivalent metals. Influences

of a variety of metals, calcination temperature of the parent dolomite, methanol/oil

molar ratios, reaction time, catalyst amount, and catalyst reuse were also investigated.

The results indicated that the calcination temperature of the parent dolomite was


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crucial factor affecting the activity and the basicity of the resulting catalyst. The catalyst

modified from dolomite claimed at 600 and 700C, followed by the precipitation from Ca

(NO3)2 and the subsequent calcination at 800C, exhibited the most active catalyst giving

the methyl ester content as high as 99.9% under the suitable reaction conditions, the

methanol/oil molar ratio of 15, amount of catalyst of 10 wt. % and reaction time of 3 h.

Sharma and Singh (2007) studied biodiesel production from extracted Karanj oil.

Molecular weight of the oil was 892.7(g). Both the acid as well as alkaline esterification

were found to be applicable to get biodiesel. They concluded that NaOH was a better

catalyst than KOH in terms of reaction yield. Maximum yield 89.5% was achieved at 8:1

molar ratio for acid esterification and 9:1 molar ratio for alkaline esterification in

presence of 0.5 wt. % catalysts (NaOH/KOH) with regular mechanical stirring.

Shah and Gupta (2007) evaluated use of lipase enzyme from Pseudomonas

cepacia for conversion ofJatropha oil to biodiesel. Commercial grade ethanol was found

compatible with enzyme-based process. The mono-ethyl esters of the long chain fatty

acids (biodiesel) were prepared by alcoholysis of Jatropha oil by enzyme lipase. The

optimization process consisted of screening of various commercial lipase preparations,

pH tuning, immobilization, varying water content in the reaction media. Varying amount

of enzyme were used and different temperature of the reaction. 98% yield (w/w) was

obtained by using P. cepacia lipase immobilized on celite at 50-58C in the presence of

45% (w/w) water in 8 h. They reported that this biocatalyst could be useful four times

without loss of any activity.

Tiwari et al (2007) worked on the response surface methodology (RSM) based on

central composite rotatable design (CCRD) was used to optimize the three important

reaction variables that was methanol quantity (M), acid concentration (C) and reaction

time (T) for reduction of free fatty acid (FFA) content of the oil to around 1% as

compared to methanol quantity (M0) and reaction time (T0) and for carrying out trans

esterification of the pretreated oil. Using (RSM), quadratic polynomial equations were

obtained for predicting acid value. The optimum combination for reducing the FFA of

Jatrophacurcas oil from 14% to less than 1% was found in 1.43% v/v H2SO4 acid catalyst,


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0.28 v/v methanol-to-oil ratio and in 88 min. reaction time at a reaction temperature of

60C as compared to 0.16 v/v methanol-to-pretreated oil ratio and 24 min. of reaction

time at a reaction temperature of 60C for producing biodiesel. This process gave an

average yield of biodiesel more than 99%. The fuel properties of J. curcas biodiesel

obtained were found comparable good to those of diesel and matches American and

European standards.

Vicente et al (2007) worked for the development and optimization of the

potassium hydroxide as a catalyst for the synthesis of fatty acid methyl esters (biodiesel)

from sunflower oil. Variables during the reaction were temperature, initial catalyst

concentration by weight of sunflower oil and the methanol: vegetable oil molar ratio,

with respect to the production of biodiesel purity and yield. It was observed that the

initial catalyst concentration was the most important factor, having a positive influence

on biodiesel purity, but a negative one on biodiesel yield. Temperature has a significant

positive effect on biodiesel purity and a significant negative influence on biodiesel yield.

The methanol: vegetable oil molar ratio was only significant for the biodiesel purity,

having a positive influence. The best conditions demonstrated were 25C, 1.3% wt. for

the catalyst concentration and a 6:1 methanol: sunflower oil molar ratio for the higher

yield as well purity of biodiesel.

The factorial design of experiments and a central composite design have been

used by Vicente et al (2007) to evaluate the influence of operating conditions on the

process of trans-esterification of sunflower oil with respect to the yield and the yield

losses due to triglyceride saponification and methyl ester dissolution in glycerol while

the variables studied were temperature, initial catalyst concentration and the methanol:

vegetable oil molar ratio. They observed that the yield increased and yield losses

decreased by decreasing catalyst concentration and temperature. However, the

methanol: sunflower oil molar ratio did not affect the material balance variables

significantly. Second-order models were obtained to predict the yield and both yield

losses.


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Zhang et al (2003) studied the economic feasibilities of four continuous

processes to produce biodiesel including both alkali and acid-catalyzed processes using

waste cooking oil and the standard process using virgin vegetable oil as the raw

material. They reported that the alkali catalyzed process using virgin vegetable oil had

the lowest fixed capital cost and acid-catalyzed process using waste cooking oil was

found more economically feasible. On the basis of these economic calculations,

sensitivity analyses were done by Zhang et al (2003). Plant capacity and prices of

feedstock oils were found most significant factors affecting the economic viability of

biodiesel manufacture.

Use of biodiesel in engines & emissions

The diesel engine exhaust emissions cause a range of health problems. However,

Demirbas (2006) observed that biodiesel is an environmentally friendly fuel that will be

useful in any diesel engine without modification.

Ideal engine fuel should produce least pollution and at the same time have

higher engine life and optimal performance. How far biodiesel can meet these demands

is a question being investigated by several workers, both engineers and

environmentalists.

Correa and Arbilla (2007) studied use of biodiesel for seven carbonyl emissions

(formaldehyde, acetaldehyde, acrolein, acetone, propionaldehyde, butyraldehyde, and

benzaldehyde) in heavy-duty diesel engine fueled with pure diesel (D) and biodiesel

blends (v/v) of 2% (B2), 5% (B5), 10% (B10), and 20% (B20). Tests were conducted using

a six cylinder heavy-duty engine, typical under 1000, 1500, and 2000 rpm. The exhaust

gases were diluted nearly 20 times and the carbonyls were sampled with SiO2C18

cartridges, impregnated with acid solution of 2,4-dinitrophenylhydrazine. The chemicalanalyses were performed by high performance liquid chromatography using UV

detection. It was reported that by using average values for the three modes of operation

(1000, 1500, and 2000 rpm) benzaldehyde showed a reduction on the emission (3.4%

for B2, 5.3% for B5, 5.7% for B10, and 6.9% for B20) and all other carbonyls showed a


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density from 860 to 885 kg/m3 for vegetable oil methyl esters or biodiesels increases the

viscosity from 3.59 to 4.63 mm2/s.

Demirbas (2007) reported that exhaust emissions of carbon monoxide (CO) from

biodiesel were 50% lower than CO emissions from petro diesel. Exhaust emissions of

particulate matter (PM) from biodiesel were 30% lower than over all particulate matter

emissions from petro diesel. It was also observed that biodiesel emission may have a

slight increase or decrease in nitrogen oxides depending on engine family; there was a

decrease in the levels of polycyclic aromatic hydrocarbons (PAH) compounds along with

nitrited PAH compounds (Demirbas, 2007) identified as potential cancer causing

compounds.

One of the largest studies of biodiesel in both on-road, off-road uses and the

testing was conducted for the military and encompassed a wide range of application

types including two medium-duty trucks, two Humvees, a heavy-duty diesel truck, a bus,

two stationary backup generators (BUGs), a forklift and an airport tow vehicle by Durbin

et al (2007). The full range of fuel testing included a California ultra-low sulfur diesel

(ULSD) fuel, different blend ratios of two different yellow-grease biodiesels, one soy-

based biodiesel, JP-8 and yellow-grease biodiesel blends with two different NOx

reduction additives. The B20-YGA, B20-YGB and B20-Soy did not show trends relative to

ULSD. Higher biodiesel blends, tested only in one vehicle, showed a tendency for higher

total hydrocarbons (THC), carbon monoxide (CO) emissions and lower particulate matter

(PM) emissions.

Methyl and ethyl esters from the oil ofJatropha curcas seeds were prepared and

the fuel properties of both ester fuels were determined according to existing standards

for biodiesel by Foidl et al (1996). Jatropha oil and blends of Jatropha biodiesel with

diesel in proportions of 97.4%/2.6%; 80%/20%; and 50%/50% by volume were tested on

a single-cylinder direct-injection engine by Forson (2004). The results covered a range of

operating loads on the engine. Brake specific fuel consumption, brake power, brake

thermal efficiency, engine torque, concentrations of carbon monoxide, carbon dioxide

and oxygen in the exhaust gases were tested as mechanical properties and were found


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similar for all fuels. 97.4% diesel/2.6% Jatropha fuel blend was observed as ideal since it

was lower net contributor to the atmospheric level by producing highest cetane

number, maximum values of the brake power and brake thermal efficiency as well as

minimum values of the specific fuel consumption. The trend of carbon monoxide

emissions was similar for the fuels but diesel fuel showed slightly lower emissions to the

atmosphere. The test showed that Jatropha oil could be conveniently used as a diesel

substitute in a diesel engine. The test further showed increase in brake thermal

efficiency, brake power and reduction of specific fuel consumption for Jatropha oil and

its blends with diesel. It was concluded that biodiesel can be used as an ignition-

accelerator additive for diesel fuel and showed even better engine performance than

the diesel fuel.

Hebbal et al (2006) selected Deccan hemp oil and non-edible vegetable oil for

the test on a diesel engine and its suitability as an alternate fuel. The viscosity of Deccan

hemp oil was reduced by blending with diesel in 25/75%, 50/50%, 75/25%, 100/ 0% on

volume basis; then analyzed and compared with diesel. Further blends were heated and

effect of viscosity on temperature was studied. The performance and emission

characteristics of blends were evaluated at variable loads at a constant rated speed of

1500 rpm and their results were compared with diesel. The thermal efficiency, brake

specific fuel consumption, brake specific energy consumption (BSEC) was comparable

with diesel; however, emissions were a little higher for 25% and 50% blends. At rated

load, smoke, carbon monoxide (CO) and un-burnt hydrocarbon (HC) emissions of 50%

blend were higher compared with diesel by 51.74%, 71.42% and 33.3%, respectively.

Pure Deccan hemp oil results were compared with the results ofJatropha and Pongamia

oil for similar works available in the literature and were well comparable. From

investigation it was suggested that up to 25% of blend of Deccan hemp oil without

heating and up to 50% blend with preheating can be substituted for diesel engine

without any engine modification.

Corrosion characteristics of biodiesel are important for long term durability of

engine parts and very little information is available on this aspect. Kaul et al (2007)


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assessed corrosion of synthesized biodiesel from the non-edible oils of Jatropha curcas,

Madhuca indica and Salvadora oleoides. They found that use of biodiesel from above

mentioned oil will lead to drastic reduction in sulphur content and increase in cetane

number which, in turn, will adversely affects the lubricity characteristics of the diesel

fuel. Using long duration static immersion test method corrosion studies on engine parts

like piston metal and piston liner were carried out by them with neat diesel procured

from one of the Indian refinery. Biodiesel from Salvadora biodiesel showed marked

corrosion on both metal parts of diesel engine whereas biodiesel from other oils

showed little or/no corrosion as compared to neat diesel (Kaul et al, 2007).

Lapuerta et al (2007) analyzed the effect of biodiesel fuels on diesel engine

emissions. The comparison was to maintain engine performance by analyzing the effect

of biodiesel fuel on engine power, fuel consumption and thermal efficiency. Highest

consensus lies in an increase in fuel consumption in approximate proportion to the loss

of heating value. Engine emissions from biodiesel and diesel fuels were compared, for

emissions: nitric oxides and particulate matter. They reported a sharp reduction in

particulate emissions.

Nabi et al (2006) investigated neat diesel fuel and dieselbiodiesel blends in a

four stroke naturally aspirated (NA) direct injection (DI) diesel engine. Comparison with

conventional diesel fuel, dieselbiodiesel blends showed emission of lower carbon

monoxide (CO) and smoke emissions but higher oxides of nitrogen (NO x) emission.

However, comparison with the diesel fuel, NOx emission with dieselbiodiesel blends

was found slightly reduced when exhaust gas recirculation was applied.

High viscosity of J. curcas oil has been considered as a potential advantage for

compression ignition (C.I.) engine Pramanik (2003) studied blends ofJatropha curcas oil

with diesel. Blends of varying proportions of J. curcas oil diesel were analyzed and

compared with diesel fuel. Effect of temperature on viscosity ofJatropha oil, blends and

biodiesel was studied and performance of the engine was evaluated in a single cylinder

C.I. engine compared with the performance obtained with diesel. Significant

improvement in engine performance was observed compared to vegetable oil alone.


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The specific fuel consumption and the exhaust gas temperature were reduced due to

decrease in viscosity of the vegetable oil. Acceptable thermal efficiencies of the engine

were obtained with blends containing up to 50% volume of Jatropha oil. From the

properties and engine test it was recommended that 4050% of oil can be substituted

for diesel without any engine modification and preheating of the blends.

Sufficient amount of trans-esterified oil esters was prepared from Karanj oil

which was used to run the farm engines (3.73 kW) for at least 8 h and composition of

fatty acids of Karanj oil studied by Raheman and Phadatare (2004). They compared the

diesel engine emissions and performance of Karanj methyl ester and diesel and

recommended Karanj oil as a good substitute.

A 5.2 kW diesel engine with alternator was used to test J. curcas biodiesel and its

blends with conventional commercial diesel fuel. A biodiesel pilot plant was developed

and used for biodiesel production from Jatropha oil. The fuel properties of Jatropha

biodiesel were found to be similar to the diesel fuel. In the case of Jatropha biodiesel

alone, the fuel consumption was about 14 per cent higher than that of diesel as

investigated by Ramesh and Sampathrajan (2008). The percent increase in specific fuel

consumption ranged from 3 to 14 for B20 to B100 fuels. The brake thermal efficiency for

biodiesel and its blends was found to be slightly higher than that of diesel fuel at tested

load conditions and there was no difference found between the biodiesel and its

blended fuel efficiencies. For Jatropha biodiesel and its blended fuels, the exhaust gas

temperature increased with increase in load and amount of biodiesel.

Carbon monoxide reduction by biodiesel was 16, 14 and 14 percent, respectively

at 2, 2.5 and 3.5 kW load conditions. The NOx emission from biodiesel increased by 15,

18 and 19 percent higher than that of the diesel fuel at 2, 2.5 and 3.5 kW load

conditions respectively.

Methyl ester (ME) of Pongamia (P), Jatropha (J) and Neem (N) were derived

through trans esterification process. Experimental investigations were carried out by

Rao et al (2008) to examine properties, performance and emissions of different blends


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(B10, B20, and B40) of PME, JME and NME in comparison to diesel. Results indicated

that B20 have closer performance to diesel and B100 had lower brake thermal efficiency

mainly due to its high viscosity compared to diesel. However, its diesel blends showed

reasonable efficiencies, lower smoke, CO and HC. Pongamia methyl ester gave better

performance as compared to Jatropha and Neem methyl esters in their study.

A single cylinder, constant speed, direct injection diesel engine was operated on

neat Jatropha oil. Injection timing, injector opening pressure, injection rate and air swirl

level were changed to study their influence on performance, emissions and combustion.

Results have been compared with neat diesel operation in a study undertaken by Reddy

and Ramesh (2006). The injection timing was varied by changing the position of the fuel

injection pump with respect to the cam; and injection rate was varied by changing the

diameter of the plunger of the fuel injection pump. A properly oriented masked inlet

valve was employed to enhance the air swirl level. Advancing the injection timing from

the base diesel value and increasing the injector opening pressure increase the brake

thermal efficiency and reduce HC and smoke emissions significantly. Enhancing the swirl

had only a small effect on emissions. The ignition delay with Jatropha biodiesel was

always found higher than that of diesel under similar conditions. Improved premixed

heat release rates were observed with Jatropha when the injector opening pressure was

enhanced. When the injection timing was retarded with enhanced injection rate, a

significant improvement in performance and emissions was noticed. In this case

emissions with Jatropha biodieselwere even lower than diesel. At full output, the HC

emission level is 532 ppm as against 798 ppm with diesel. NO level and smoke with

Jatropha biodiesel were found to be 1162.5 ppm and 2 BSU while they were 1760 ppm

and 2.7 BSU with diesel as reported by them.

It was observed that methyl ester of Karanj oil had slightly reduced thermal

efficiency as compared to diesel. The brake specific fuel consumption, exhaust gas

temperature and HC, CO and NO emission of methyl ester of Karanj oil was slightly

higher as compared to diesel in a study undertaken by Srivastava and Verma (2007). It

was observed that almost all properties of the methyl ester of Karanj oil were found


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quite closer to those of the diesel oil. Therefore, they concluded that methyl ester of

Karanj oil can be used as an alternative renewable source of energy.

Sahoo et al (2007) reported that 0.65% by volume H2SO4 and a molar ratio of 6:1

gave maximum conversion efficiency of free fatty acids to triglycerides and thereby

reducing the acid value of the product below 4 mg KOH/g in acid based reaction and in a

same manner molar ratio of 9:1 and the 1.5% by weight of potassium hydroxide was

found to give the maximum ester yield for reaction duration of 4 h in the case of alkali

trans-esterification reaction. This diesel was examined for engine performance without

any engine hardware modifications. The 100% biodiesel was found to be ideal since it

improved the thermal efficiency, brake specific energy consumption of the engine by

0.1% and the exhaust emissions were reduced. Smoke emissions also reduced by 35%

for B60 as compared to neat petro-diesel. The objective of this study was to ascertain

suitability of these fuels for engine application. Based on the exhaustive engine tests, it

was concluded that polanga based biodiesel can be adopted as an alternative fuel for

the existing conventional diesel engines without any major hardware

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