A Report of Minor Research Project - Assumption...
Transcript of A Report of Minor Research Project - Assumption...
A Report of
INVESTIGATION ON THE POTENTIAL OF SOME
SELECTED WETLAND PLANTS FOR THE
BIODIESEL PRODUCTION
Ms. NEETHU CYRIL
(1936-MRP/14
Assistant Professor
Assumption Autonomous
Changanacherry, Kottayam, Kerala, 686101
University Grants Commission
A Report of Minor Research Project
INVESTIGATION ON THE POTENTIAL OF SOME
SELECTED WETLAND PLANTS FOR THE
BIODIESEL PRODUCTION
Ms. NEETHU CYRIL,
MRP/14-15/KLMG034/UGC-SWRO)
Assistant Professor, Department of Chemistry
Assumption Autonomous College
Changanacherry, Kottayam, Kerala, 686101
Submitted to
University Grants Commission, New Delhi
January 2017
INVESTIGATION ON THE POTENTIAL OF SOME
SELECTED WETLAND PLANTS FOR THE
ACKNOWLEDGEMENTS
The present study was supported by the University grants commission of India
under the grant No:1936-MRP/14-15/KLMG034/UGC-SWRO.
I would like to express my sincere thanks to Dr Sr Amala SH, Principal,
Assumption College, Changanacherry for her inspiration, constant support and for
providing necessary facilities for carrying out this work.
I wish to thank Dr. Jissy Mathew, HOD, Department of Chemistry, Dr. Marykutty
CV, former HOD, Assumption College, Changanacherry and my colleagues for their
constant encouragement and support throughout the period of my work.
I deeply express my gratitude to my parents and family members for their
constant encouragement, valuable support and understanding.
Above all I thank God Almighty for his grace and blessings....
Neethu Cyril
CONTENTS
Abstract 1
1. Introduction 2
1.1 Global energy needs and significance of a sustainable energy resource 2
1.2 Biodiesel – A Clean Energy Source 4
1.3 Transesterification 4
1.3.1 One step transesterification
1.3.2 Two step acid base transesterification
1.3.3 Advanced transesterification process
Ultra sound assisted transesterification
Microwave assisted transesterification
1.4 Oil sources for Biodiesel 9
1.5 Environmental Impact of Biodiesel 10
1.6 Scope of present investigation 12
1.7 Objectives of the present investigation 13
References
2. Review of Literature 16
2.1 Indian Scenerio 16
2.2 Triglyceride as diesel fuels 21
2.3 Transesterification 23
References
3. Materials and Methods 29
3.1 Materials 29
3.2 Methodology 30
3.2.1 Extraction of oil
3.2.2 Determination the oil yield
3.2.3 Determination of Free Fatty Acids
3.2.4 Determination of fatty acid composition of oils
3.2.5 Transesterification of oils
Two step acid- base catalysed transesterification
Acid pre-esterification
Base catalysed transesterification
Transesterification reaction with ultrasound
4. Results and Discussion 34
4.1 Extraction of oil from of selected wetland plants 34
4.2 Estimation of acid value and free fatty acid content (FFA) 34
4.2.1 Procedure for estimation of acid value
4.2.2 Procedure for estimation of FFA
4.3 Fatty acid profile of selected wetland plants 36
4.4 Transesterification Studies 40
4.4.1 Alkali-catalysed transesterification studies of Nymphaea nouchali
4.4.2 Two- step biodiesel production of Pongamia Pinnatta seed oil
4.4.3 Two- step biodiesel production of Thespesia Populnea oil
4.5 Effect of ultrasound on transesterification of oils 48
References
5. Conclusion 51
GC MS results 53
1
Abstract
The present work aims at the sustainable utilisation of our wetland ecosystem for
the production of energy and thus to promote awareness of the importance of wetland
conservation to the general public.In the present work, wetland plants were collected
from the resource based areas of southern Kerala mainly from Kuttanadu region for
screening their potential for biodiesel production. However, taking into account the
magnitude of its abundance, the studies conducted are still negligible. Plants used in the
study were Nymphea nouchali,Thespesia populnea, Pongamia pinnattaL, Derris
trifoliata and Canvalia cathartica.The fatty acid compositions of plants were studied by
Gas Chromatography – Mass Spectroscopy. Amongthe wetland plants,Thespesia and
Pongamia were identified as a cheap and renewable raw material for biodiesel
production.Also, biodiesel yield from conventional method is compared with the
ultrasound assisted transesterification.Thus biodiesel production using ultrasound could
be considered as a potential route for the production of biodiesel, capable of meeting
high demands in short time period, with energy costs that may be less than the expenses
with the conventional method. The identified fatty acids in the hexane extract of
Thespesia populnea, Derris trifoliate and Canavalia cathartica exhibit multifunctional
biological activity. The oil of these seeds contained a significant percentage of
pharmacologically active linoleic and alpha-linolineic fatty acids. The present findings
also proved the traditional use of these plants in the folk medicine.
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Chapter 1
INTRODUCTION
1.1 Global energy needs and significance of a sustainable energy resource.
Global energy demand is growing at a fast pace. As the world economy expands,
more energy will be needed to fuel the higher levels of activity andliving standards.It
seems clear that significantly more energy will be required over the next twenty years to
enable the world economy to grow and prosper.Fossil fuels remain the principal source
of energy powering the world economy.Oil demand increases by almost 20 Mb/d over
the outlook, with growing use in Asia for both transport and industry. Population and
income are the key drivers behind growing demand for energy.The growth in the world
economy means more energy is required; energy consumption increases by 34% between
2014 and 2035.More than half of the increase in global energy consumption is used for
power generation as the long-run trend towards global electrification continues: the share
of energy used for power generation rises from 42% today to 45% by 2035.If production
and consumption of coal continue at the rate as in 2015, proven and economically
recoverable world reserves of coal would last for about 150 years.This is much more
than needed for an irreversible climate catastrophe. Thus it is important to find out an
alternative energy resources to improve the energy efficiency.Technologies that promote
sustainable energy include renewable energy sources such as hydroelectricity, wind
energy, solar energy, geothermal energy, bioenergy and so on. Biofuel plays an
important role among the renewable energy resources for meeting our global energy
demands.
Biofuels are known as transformative fuels because they can move us towards a
more renewable and sustainable fuel source. Biofuels are: Bioethanol, Biodiesel,
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Charcoal and Biohydrogen. Plants use a nifty biological mechanism called
photosynthesis to convert sunlight energy into chemical energy. This mechanism is the
single source for all biofuels. A recent survey conducted in 2009 by the US department
of energy found that biodiesel reduces carbon dioxide emissions by 78%, when
compared to petroleum diesel.
According to energy statistics 2016, Ministry of Statistics and Programme
Implementation, the total potential for renewable power generation in the country as on
31.03.15 is estimated at 896603 MW. This includes wind power potential of 102772
MW (11.46%), Small-hydro power potential of 19749 MW (2.20%), Biomass power
potential of 17,538 MW (1.96%), 5000 MW (0.56%) from bagasse-based cogeneration
in sugar mills and solar power potential of 748990 MW (83.54%).
Fig 1: Sourcewise estimated potential of renewable power in India as on 31.03.15 by
the Ministry of Statistics and Programme Implementation.
India’s substantial and sustained economic growth is placing enormous energy
demand in agriculture, industrial, commercial and household sectors has increased
84%
11%
2%
2%1% 0%
Sourcewise Estimated Potential of Renewable Power in
India as on 31.03.15
solar power wind energy small hydro power
Biomass power cogeneration bagasse waste to energy
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tremendously and placed enormous pressure on its resources. India’s crude oil and
natural gas production has been declining in recent years. This leads to an increase in the
dependency on imports. Presently, almost 83% of India’s crude oil availability is through
imports. To reduce the dependency on imports, Federal and State governments are
encouraging the use of renewable sources of energy.
On account of the increasing need for energy, the government should formulate
policies and programmes for the development of new and renewable sources of energy.
1.2 Biodiesel – AClean Energy Source
Biodiesel is a biofuel produced from an oil product. Biodiesel is a straight chain
of carbon atoms and depending on the source of feedstock oil can either be saturated or
unsaturated. Biodiesel can be defined as mono alkyl esters of free fatty acids from
vegetable oil and animal fats[1]. It can be used either pure, or in blends with petroleum
based diesel fuel. All oils are made up of triacylglycerides, which are three fatty acid
chains connected to a three carbon skeleton known as glyceride.
1.3 Transesterification
Transesterification is a simple process that chemically converts vegetable oil by
treating it with sodium hydroxide and alcohol turning it into a fatty acid methyl ester
(FAME). Obtaining pure esters after transesterification was not easy, since there are
impurities in the esters, such as di and monoglycerides[2]. The examples of alcohol that
can be used in the transesterification of triglycerides are methanol, ethanol, propanol,
butanol and amyl alcohol. Van Gerpen investigated the effect of different alcohol types
on transesterification[3]. The high conversion rates found for long chain alcohols
compared with methyl ester are due to the higher reaction temperatures allowed by their
boiling points. Methanol and ethanol are most frequently used alcohols for
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transesterification. Catalyst used in the transesterification of triglycerides can be
classified as homogeneous, heterogeneous and enzyme catalyst. In this transesterification
process, there are two types of homogeneous catalyst which is acid catalyst (H2SO4 or
HCl) and alkali catalyst (KOH or NaOH). In heterogeneous catalytic process, usually the
catalyst is a solid and the reactant and product are in liquid or gaseous form. Alkaline
earth metal oxides, anion exchange resins, various alkali metal compounds supported on
alumina and various types of zeolites can be used as heterogeneous catalyst in the
production of biodiesel. Homogeneous basic catalyst provides much faster reaction rates
than heterogeneous catalyst, but it is difficult to separate homogeneous catalyst from the
reaction mixture. Enzymes can also be used as biocatalysts in the reaction.
Fig 2: Transesterification reaction
For an alkali based transesterification, oil and alcohol should be anhydrous [4] as
the presence of water can produce soap. The soap lowers the yield of esters and makes
the separation of ester and glycerol difficult. Also, the free fatty acid content of the
feedstock must be less than 2% [5] for effective transesterification. If more water and
free fatty acids are in the oil, acid catalysed transesterification can be used. The acid
value and hence free fatty acid content of crude oil samples were determined by a
standard titrimetry method. Free fatty acid content in the oil will result in the formation
of soap and water. The soap inhibits the biodiesel- glycerine separation process. Free
fatty acids are a problem because they make the fuel acidic, which will damage the
engine. There are various ways to deal with them. If the level of free fatty acids is less
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than about 2%, the oil can be still processed with an alkali catalyst. In this case, an
amount of extra catalyst should be added to increase the yield of biodiesel. Above
2%,the amount of soap inhibits the separation of glycerine. The most suitable method is
to esterify the FFA’s using an acid catalyst. The acid catalyzes the esterification reaction
of fatty acids to methyl esters. When the level of free fatty acids has been reduced to
below 0.5%, the mixture can be passed through the transesterification process as if it
were refined oil.
Transesterification is the reaction of a fat or oil triglyceride with an alcohol to
form esters and glycerol. A catalyst is usually added to increase the rate of the reaction.
Since the reaction is reversible, excess alcohol is used to shift the equilibrium to the
product side. The main by-product of the reaction is glycerine. Transesterification is
widely used to reduce vegetable oil viscosity[6].The transesterification reaction proceeds
well in the presence of some homogeneous catalysts such as potassium hydroxide and
sodium hydroxide or heterogeneous catalysts such as metal oxides or carbonates. Even
enzymes like lipases can catalyse transesterification[7]. Sodium hydroxide is preferred
over potassium hydroxide because of its low cost and high product yield. But KOH is
more soluble in alcohol than sodium hydroxide.
1.3.1 One step transesterification
Esters, in the presence of a base, form an anionic intermediate, which can
dissociate back to the new ester or form a new ester. Base catalysed transesterification
proceeds faster than the acid catalysed reaction. In the first step, the base reacts with the
alcohol producing an mediate from which the alkyl ester is formed. Diglycerides and
monoglycerides are converted by the same mechanism into a mixture of alkyl esters and
glycerol. Alkoxides are better catalysts than hydroxides. Alkoxides are prepared by
dissolving the clean metals in analkoxide .Alkoxide ion attacks the carbonyl carbon of
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the triglyceride generating a tetrahedral interhydrous alcohol. While using NaOH and
KOH, water is formed as a by product which will further result in soap formation. The
unwanted saponification reduces the ester yields and makes the separation of glycerol
difficult. Carbonates can be used as a substitute for NaOH.
Fig 3: Mechanism of alkali catalysed transesterification of vegetable oils.
1.3.2 Two step acid base transesterification
Two-step process was usually used for the production of biodiesel. the free fatty
acid content of the feedstock must be less than 2% [5] for effective transesterification. If
more water and free fatty acids are in the oil, acid catalysed transesterification can be
used. Initially sulphuric acid was used to catalyse the esterification of free fatty acids
present in the oil. After the reduction of free fatty acid content of the oil,
transesterification reaction was carried out.
For acid catalysed esterification, solutions of sulphuric acid in anhydrous alcohol
were prepared at room temperature. The sulphuric acid percentage was based on the
weight of the oil to be reacted. The acid catalyst is dissolved into alcohol by vigorous
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stirring in a small reactor. The oil is transferred into the biodiesel reactor and then the
catalyst/alcohol mixture is added into the oil. It is already reported in the literature that a
large excess of alcohol (15 to 35 moles per mole of fatty acid) should be used when
sulphuric acid is employed as a catalyst[8]. Freedmann and pryde [9] mentioned that a
30:1 molar ratio of alcohol to oil with 1% sulphuric acid gave good conversion after 44 h
of heating at 60 0C.They highlighted that if oil has more than 1% free fatty acid, the acid
catalyst will be much more fruitful than the alkali catalyst. Acid catalysed esterification
is much slower than alkali-catalysed reaction. The mechanism of acid catalysed
transesterification of vegetable oil is shown below:
Fig 4: Mechanism of acid catalysed transesterification
1.3.3 Advanced transesterification process
1.3.3.1 Ultra sound assisted transesterification.
Transesterification reaction can be accelerated by the application of
ultrasound.Biodiesel production from canola oil withmethanol was studied in the
presence of a base-catalyst by a circulation process at room temperature[10]. It was
found that the conversion of triglycerides to fatty acid methyl esters was greater than
99% within the reaction time of 50 min. The procdure for ultra sound assisted
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transesterification is similar to simple transesterification process. In the first step, the
reaction mixture is sonicated without adding the base catalyst. In the second step,
catalyst is added and then sonicated. It is already reported in the literature that the
influence of ultrasound on transesterification reaction is of purely physical nature[11].
No radical species are produced during the reaction. Due to microturbulence generated
by cavitation bubbles an emulsion is created between oil and alcohol. The interfacial area
between oil and alcohol increases, which accelerates the reaction. The optimum alcohol
to oil molar ratio for the reactions varies depending on the frequency and intensity of
ultrasound and type of sonicator [11].A study was carried out on the hydrolysis of waste
cooking oil (WCO) under solvent free condition using commercial available
immobilized lipase (Novozyme 435) under the influence of ultrasound irradiation
[12]. The activation energy and thermodynamic study shows that the hydrolysis reaction
is more feasible when ultrasound is combined with mechanical agitation as compared
with the ultrasound alone and simple conventional stirring technique. Application of
ultrasound considerably reduced the reaction time as compared to conventional reaction
[12].
1.3.3.2 Microwave assisted transesterification.
Microwave can be used to increase the efficiency of biodiesel production. Nezihe
Azcanet al studied the efficiency of microwave assisted transesterification for the
biodiesel production and the results shows that that microwave heating has effectively
increased the biodiesel yield and decreased the reaction time[13].
1.4 Oil sources for Biodiesel
The source of biodiesel depends on the crops suitable to the regional climate.
Selection of biodiesel feedstock depends on the oil percentage and the yield per
hectare[14].The most commonly used oils for the production of biodiesel are
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soyabean[15], cotton seed[16], palm[17], rapeseed[18], canola and
jatropha[19].However, edible oils always compete with food and therefore some species
of plants yielding non-edible oils play a major role in providing resources. But as India
still imports huge quantities of edible oils, the use of edible oils for diesel engine fuel is
not feasible. These plants may be grown on a massive scale on agricultural or waste
lands, so that the primary resourcemay be available to produce biodiesel on commercial
scale. In India, Jatropha and Pongamia pinnata oilseeds were cultivated on wasteland
but the cultivation of these two has been failed.Much effort has been devoted to develop
new biodiesel production processes by using cheaper feedstock.
Edible oils Non edible oils Other sources
Soyabeans[15] Almond Algae
Rapeseed[20] Jatropha Fungi
Coconut[21] Pongamia glabara Waste cooking oil
Wheat[22] Mahua
Cotton seed Jojoba
Rice bran Rubber[23]
Barley Palm
canola Tobacco seed[24]
Table 1: Biodiesel sources
1.5 Environmental Impact of Biodiesel
Vegetable oil has a heating value lower than diesel oil; however vegetable oil has
a high viscosity and low volatility which leads to incomplete combustion and forms
carbon deposits in the fuel injectors. The main advantages of using biodiesel are its
renewability, better-quality exhaust gas emissions, its biodegradability and given that all
the organic carbon present is photosynthetic in origin, it does not contribute to a rise in
the level of carbon dioxide in the atmosphere and consequently to the greenhouse effect.
Transesterification process is most popular than other methods because it is simple and
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glycerol is obtained as a by-product. Glycerol has a commercial value. Glycerol is
obtained proximately 10% of the oil or fat and proximately one ton of glycerine can be
obtained for every ten tones of biodiesel engenderment. Biodiesel is defined as the mono
alkyl esters of long chain fatty acids derived from renewable feed stocks like vegetable
oils or animal fats. Most of the properties of biodiesel are comparable to petroleum based
diesel fuel.
Property Test
method
ASTM D ASTM D6751
EN14214: 2003 975(Diesel)
(biodiesel,B100)
Limit Limit Test
method Limit
Flash point D 93 325 K min 403 K min ISO/CD3679
374 K min
Water and sediment
D 2709 0.05 max % vol
0.05 max % vol
-
Kinematic viscosity (at 313 K)
D 445 1.3-4.1 mm2/5 1.9-6.0 mm2 /s
EN/ISO310 3.5-5.0
Sulphated ash D 874 - 0.02 max % wt
ISO3987 0.02max % (m/m)
Ash D 482 0.01 max % wt - - -
Sulphur D 5453 0.05 max % wt - - -
Sulphur D 2622 / 129
- 0.05 max % wt
- -
Copper strip corrosion
D130 No.3 max No.3 max Rating No.1 max
Cetane number
D 613 40 min 47 min EN ISO 5165
51 min
Aromaticity D 1319 35 max % vol -
Carbon residue
D 4530 - 0.05 EN ISO1-370
0.3 max
Carbon residue
D 524 0.35 max %mass
- - -
Distillation temp (90% volume recycle)
D 1160 555 K min- 611 K max
- - -
Table 2: Standards for biodiesel
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1.6 Scope of present investigation
In India, wetlands are distributed in different geographical regions ranging from
Himalayas to Western Ghats. Wetlands provide us with food, fodder, fuel and water for
domestic and industrial purposes. Wetlands support a number of rare and endangered
species of flora and fauna. The services provided by wetland ecosystem are endless and
they are one of the most productive and complex ecosystems on our planet acclimatized
to extraordinary conditions. The biodiversity rich wetland ecosystem of India is
shrinking due to increasing biotic and abiotic pressures. The aim of the present work is
the sustainable utilisation of our wetland ecosystem for the production of energy and thus
to promote awareness of the importance of wetland conservation to the general public.
Plants are the unique biological resources form the basis of life. Due the diverse
ecological conditions of India, we are lucky to have many oil yielding wild plants which
can be utilized for the production of biodiesel. Woefully like other fields, no scientific
investigation has been done on biodiesel prior to this, because the people are unaware to
use these resources for development of this technology due to lack of interactions
between our industries and research institutions. In this contest the present study is a
stepping stone to initiate biodiesel research in India.
More than 100 oil bearing plants have been identified, among which
Calophyllum inophyllum L, Ricinus communis L, Soyabean and Jatropha curcas L are
considered to be potential biodiesel sources. However no systematic studies of wetland
species are available for biodiesel production.
In the present work, wetland plants were collected from the resource based areas
of southern Kerala. Wetlands in the Kuttanadu region are rich in Nymphea species.
However, taking into account the magnitude of its abundance, the studies conducted are
still negligible. In this search, petals and stamens of Nymphea nouchali were collected
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for oil extraction. Also other plants used in the study were Thespesia populnea,
Pongamia pinnattaL, Derris trifoliata and Canvalia cathartica.
1.7 Objectives of the present investigation
The objectives of the present work were the following:
To identify and shortlist local wetland plants that are viable sources of Biodiesel, in
order to establish a rationale for large scale plantation for the most preferable
Biodiesel producing plants.
Extraction of oil from these selected wetland plants.
To study the fatty acid profile of these selected wetland plants.
Transesterification of oil for biodiesel production.
To study the effect of ultrasound on the biodiesel yield.
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References
1. Krawczyk, T., Biodiesel. Alternative fuel makes inroads but hurdles remain. 1996.
2. Ma, F. and M.A. Hanna, Biodiesel production: a review. Bioresour Technol, 1999. 70(1):
p. 1-15.
3. Canacki, M. and J.V. Gerpen, Biodiesel production via acid catalysis. Transactions of the
American Society of Agricultural Engineers, 1999. 42: p. 1203-1210.
4. Wright, H., et al., A report on ester interchange. Oil & Soap, 1944. 21(5): p. 145-148.
5. Meher, L.C., V.S.S. Dharmagadda, and S.N. Naik, Optimization of alkali-catalyzed
transesterification of Pongamia pinnata oil for production of biodiesel. Bioresour Technol,
2006. 97(12): p. 1392-1397.
6. Sinha, S., A.K. Agarwal, and S. Garg, Biodiesel development from rice bran oil:
Transesterification process optimization and fuel characterization. Energy Conversion and
Management, 2008. 49(5): p. 1248-1257.
7. Macrae, A., Lipase-catalyzed interesterification of oils and fats. Journal of the American
Oil Chemists’ Society, 1983. 60(2): p. 291-294.
8. Formo, M.W., Ester reactions of fatty materials. Journal of the American Oil Chemists
Society, 1954. 31(11): p. 548-559.
9. Freedman, B. and E. Pryde, Fatty esters from vegetable oils for use as a diesel fuel. 1982,
Dept. of Agriculture, Peoria, IL.
10. Thanh, L.T., et al., Ultrasound-assisted production of biodiesel fuel from vegetable oils in
a small scale circulation process. Bioresour Technol, 2010. 101(2): p. 639-645.
11. Kalva, A., T. Sivasankar, and V.S. Moholkar, Physical mechanism of ultrasound-assisted
synthesis of biodiesel. Industrial & Engineering Chemistry Research, 2008. 48(1): p. 534-
544.
12. Waghmare, G.V. and V.K. Rathod, Ultrasound assisted enzyme catalyzed hydrolysis of
waste cooking oil under solvent free condition. Ultrason Sonochem, 2016. 32: p. 60-67.
13. Azcan, N. and A. Danisman, Microwave assisted transesterification of rapeseed oil. Fuel,
2008. 87(10): p. 1781-1788.
14. Singh, S. and D. Singh, Biodiesel production through the use of different sources and
characterization of oils and their esters as the substitute of diesel: a review. Renewable
and Sustainable Energy Reviews, 2010. 14(1): p. 200-216.
15. Freedman, B., R.O. Butterfield, and E.H. Pryde, Transesterification kinetics of soybean oil
1. Journal of the American Oil Chemists’ Society, 1986. 63(10): p. 1375-1380.
16. Köse, Ö., M. Tüter, and H.A. Aksoy, Immobilized Candida antarctica lipase-catalyzed
alcoholysis of cotton seed oil in a solvent-free medium. Bioresour Technol, 2002. 83(2): p.
125-129.
15
17. Darnoko, D. and M. Cheryan, Kinetics of palm oil transesterification in a batch reactor. J
Am Oil Chem Soc, 2000. 77(12): p. 1263-1267.
18. Saka, S. and D. Kusdiana, Biodiesel fuel from rapeseed oil as prepared in supercritical
methanol. Fuel, 2001. 80(2): p. 225-231.
19. Senthil Kumar, M., A. Ramesh, and B. Nagalingam, Investigations on the use of Jatropha
oil and its methyl ester as a fuel in a compression ignition engine. Journal of the Institute
of Energy, 2001. 74(498): p. 24-28.
20. Billaud, F., et al., Production of hydrocarbons by pyrolysis of methyl esters from rapeseed
oil. Journal of the American Oil Chemists’ Society, 1995. 72(10): p. 1149-1154.
21. Abigor, R., et al., Lipase-catalysed production of biodiesel fuel from some Nigerian lauric
oils. Biochem Soc Trans, 2000. 28(6): p. 979-981.
22. Ugarte, D.G.D.L.T. and D.E. Ray, Biomass and bioenergy applications of the POLYSYS
modeling framework. Biomass and Bioenergy, 2000. 18(4): p. 291-308.
23. Ramadhas, A.S., S. Jayaraj, and C. Muraleedharan, Biodiesel production from high FFA
rubber seed oil. Fuel, 2005. 84(4): p. 335-340.
24. Giannelos, P., et al., Tobacco seed oil as an alternative diesel fuel: physical and chemical
properties. Industrial crops and products, 2002. 16(1): p. 1-9.
16
Chapter 2
REVIEW OF LITERATURE
The biodiesel is an alternative to reduced CO2 and sustainable use of
bioresources. Moreover, the fuel will reduce country over dependence on imported petro-
diesel. Hence, detailed screening process of all available virgin or plant and animal
origin coming up with some restrictions. The cheapest feedstock available is the key
factor for a low cost biodiesel. The recent focus is to find oil-bearing plants that produce
non-edible oils as the feedstock for biodiesel production. Biodiesel obtained from neat
vegetable oil is costly compared to the petroleum diesel fuel. The main advantages of
using biodiesel are its renewability, better-quality exhaust gas emissions, its
biodegradability and given that all the organic carbon present is photosynthetic in origin,
it does not contribute to a rise in the level of carbon dioxide in the atmosphere and
consequently to the greenhouse effect[25]. Recently, a lipase-catalyzed esterification of
various kinds of vegetable oils using an organic solvent or a solvent free system was
studied by environmental friendly process[26]. Research has recently indicated that the
lipids contained in sewage sludge are a potential feedstock for biodiesel[27].Researchers
are also developing microalgae that produce oils, which can be converted to
biodiesel[28]. Much effort has been devoted to develop new biodiesel production
processes by using cheaper feedstock[29].The present study concentrates on screening
untapped natural resources like the lipids present in the selected aquatic plants of
Kuttanad wetland ecosystem of Kerala, India for the production of biodiesel.
2.1 Indian Scenerio
The Planning Commission of India established the National Biodiesel Mission
(NBM) for the development and commercialization of biodiesel from Jatropha and
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Pongammia seeds. The Cultivation of these two cultivars started in the state of Andhra
Pradesh. Based on extensive research carried out in agricultural research centers, it was
decided to use Jatropha curcas oilseed as the major feedstock for India’s biodiesel
programme. NBM was planned for two phases. Phase I was termed as demonstration
phase and has been carried out from year 2003 to 2007 (Planning Commission, Govt. of
India, 2003). The work done during this phase were development of Jatropha oilseed
nurseries, cultivation of Jatropha on 400,000 hectares (ha) waste land, setting up of seed
collection and Jatropha oil expression centers, and the installation of 80,000 Mt/year
transesterification to produce biodiesel from Jatropha oil. Phase II planned with a self
sustaining expansion of the programme leading to the production of biodiesel to meet
20% of the country’s diesel requirements by 2011–2012. The lack of assured supplies of
vegetable oil feedstock has foiled efforts by the private sector to set up biodiesel plants in
India. Commercial biodiesel production has not yet started in India. So far only two
firms, Naturol Bioenergy Limited (NBL) and Southern Online Biotechnologies, have
embarked on biodiesel projects, both in the southern state of Andhra Pradesh. Naturol
Bioenergy Limited (NBL), a joint venture with the Austrian biodiesel firm Energea
Gmbh and the investment firm Fe Clean Energy (USA), has planned to install a 300
tonnes/day (t/d)/(90,000 tonnes/year) (t/y) biodiesel plant in Kakinada, Andhra
Pradesh[30].The State Government allocated 120,000 ha of land for Jatropha cultivation
to the firm but cultivation has not yet begun or is in initial stage. The farmers were
demanding that the market set the oilseed price, but NBL wants the government to fix a
price to reduce its risks in production. Southern Online Biotechnologies has a 30 t/d
(9000 t/y) project, which would require about 9500 t/y of oil. It was expected to get
about 6000 t/y through cultivation of Jatropha and Pongamia pinnata oilseeds on
wasteland, and plans to make up the balance through animal fats, but the cultivation of
18
these two have been failed. So, there are many constraints for the biodiesel production in
India and phase I of NBM has not given the anticipated results. Azam MM etal studied
thefatty acid profiles of seed oil methyl esters of 75 plant species [31]. Out of these
plants, based on saponification value, iodine number, cetane number and fatty acid
profile, fatty acid methyl esters of 36 species meet the specification of Biodiesel standard
of USA is listed in the (table 1).
Khan et al. reviewed prospects of biodiesel production from micro algae in India
and this paper is an attempt to review the potential of micro algal biodiesel in
comparison to the agricultural crops and its prospects in India[32]. The existing biodiesel
production process is neither completely “green nor renewable’’ because it utilizes
fossil fuels, mainly natural gas as an input for methanol production, also the catalyst
currently in use are highly caustic and toxic . To overcome this process, a new method is
used in which waste vegetable oil and non edible plant oils and biodiesel feed stock and
nontoxic, inexpensive and natural catalyst[33].
19
Table 1 - Fatty acid composition of oils
TABLE 3: a oil from kernel, b oil from seeds, osa: other saturated acids, uk: unknown
20
Table 1 - Fatty acid composition of oils
a oil from kernel, b oil from seeds, osa: other saturated acids, uk: unknown
21
2.2 Triglyceride as diesel fuels
Vegetable oil and animal fats are extensively used as the major source in the
production of biodiesel. The characteristics of biodiesel are close to diesel fuels, and
therefore becomes an alternative source to replace the diesel fuels. Biodiesel has
viscosity close to diesel fuels. Table 2 shows the comparison of fuel properties between
diesel and biodiesel[34].
Table 2 - Comparison of fuel properties between diesel and biodiesel
Depending upon the climate and soil conditions, different countries are
looking for different types of vegetable oils as substitutes for diesel fuels. For
example soyabean oil in US, rapeseed oil in Europe is being considered. However,
edible oils always compete with food and therefore some species of plants yielding
22
non-edible oils play a major role in providing resources. But as India still imports
huge quantities of edible oils, the use of edible oils for diesel engine fuel is not
feasible. These plants may be grown on a massive scale on agricultural or waste
lands, so that the primary resourcemay be available to produce biodiesel on
commercial scale. In India, Jatropha and Pongamia pinnata oilseeds were cultivated
on wasteland but the cultivation of these two has been failed.Much effort has been
devoted to develop new biodiesel production processes by using cheaper
feedstock.The present study aims to screen the suitable wetland plants as energy
crops from a tropical wet-land ecosystem, where the high production of biomass
occurs within a short time span. This biomass is considered as nuisance to the
farmers as well as local people. Moreover it causes economic threat to the farmers.
Hence the study aims to use the biomass for the production of energy. There are
limited studies so far reported from India on the production of biodiesel from wet-
land plants and the present attempt has the significance in the energy sector of the
country especially in the biodiesel production.
Kerala is one of the green States of India and is well known for its wetlands.
The total wetland area in Kerala is 160590 ha[35].In Kerala, wetlands are under
extreme pressure compared to any other state. Partitioning by funds, reclamation and
consequent shrinkage have been implicated as the major reasons for the destruction
of habitat and dwindling of resources. The study aims to find out certain potential
wetland plant species from a tropical wetland system for biodiesel production. The
distribution of plants in the different wetlands is given in the table below[36]:
23
Distribution Trees Shrubs Climbers Herbs Total % to total
species
Coastal wetlands 51 34 40 393 518 71
Inland wetlands 87 47 43 311 488 67
Both in coastal and inland wetlands
35 18 18 210 281 39
Only in coastal wetalnds
16 16 22 183 237 33
Only in inland wetlands
52 29 25 101 207 29
Table 4 - Distribution of plants in the different wetlands
In the present study, some locally available wetland plants are randomly selected
for screening their potential for biodiesel production.There are many unexploited plant
species, which contains oil that can be extracted and used as bio-diesel. Some
unexploited plant species were experimented in this present study for its content. A
preliminary work was done on the transesterification of the crude oil extracted from T.
populnea seed under standard conditions with sodium methoxide as catalyst[37]. Many
research studies had been done on the transesterification of pongamia oil[38,
39].However, the fatty acid profile of plants varies with the external environment. In the
present study, fatty acid profiles of wetland plants in kerala are explored to study their
potential for biodiesel production.
2.3 Transesterification
Different methods have been employed to convert oils and fats to be used in diesel
engines. Among them, transesterification is one of the promising methods for the
production of biodiesel. Transesterification is the process of converting an ester into
another ester by reaction with an alcohol using a suitable catalyst. Transesterification of
TG is a stepwise reaction where the TG reacts first with the alcohol to produce a DG and a
mono-alkyl ester molecule, then the DG reacts similarly to produce a MG and a second
molecule of mono-alkyl ester and finally the MG reacts with another alcohol to produce
24
glycerol and a third molecule of mono-alkyl ester [15]. Transesterification reaction can be
done in the presence of homogeneous catalyst, heterogeneous catalyst and an enzyme.
Homogeneous catalysis can be performed by using base catalyst or an acid catalyst.
Alkaline transesterification is found to be more effective than acid catalysed reaction for
vegetable oil containing FFA level less than 0.5%[40]. Also, it can be performed at lower
temperatures than heterogeneous catalysis. A comparison is made of different basic
catalysts (sodium methoxide, potassium methoxide, sodium hydroxide and potassium
hydroxide) for methanolysis of sunflower oil and their studies shows that although all the
transesterification reactions were quite rapid and the biodiesel layers achieved nearly 100%
methyl ester concentrations, the reactions using sodium hydroxide turned out the
fastest[41].
Efforts have also been made to use heterogeneouscatalysts for the transesterification
of triglycerides. Heterogeneous catalysts have many advantages over homogeneous
catalysts. They can be easily separated from the products after the reaction and thus it can be
reused. However, the heterogeneous catalytic reaction should be done at higher temperature
than homogenous catalysis with an excess of alcohol. Research work has been conducted to
use compounds of calcium and barium, to produce the methyl esters of rapeseed oil.This
research showed that the transesterification of rapeseed oil by methyl alcohol can be
catalysed effectively by basic alkaline-earth metal compounds: calcium oxide, calcium
methoxide and barium hydroxide. Calcium catalysts, due to their weak solubility in the
reaction medium, are less active than sodium hydroxide. However, calcium catalysts are
cheaper and lead to decreases in the number of technological stages and the amount of
unwanted waste products[42]. It was already reported in the literature that mixed oxides of
zinc and aluminium could be used for the transesterification of vegetable oils[43]. Zeolites
can be used as effective catalyst for transesterification reaction. Zhongjun etal studied the
25
transesterification of olive oil with ethanol in the presence of different types of microporous
zeolites (BEA type Beta zeolite and MFI type ZSM-5 zeolite) and micro-mesoporous
zeolites (MFI type ZRP-5 zeolite) with various Si/A1 ratios[44].The results showed that the
zeolites with high Si/Al ratios had better catalytic performance. The catalytic activities of
different metal complexes were compared with classical alkali and acid based
trasesterification[45].It was found that all complexes are active Sn 2+≫Zn 2+>Pb 2+≈Hg 2+.
Transesterification of soybean oil with methanol was carried out at 60, 120, and 150 °C in
the presence of a series NaX faujasite zeolite, ETS-10 zeolite, and metal catalysts[46]. The
ETS-10 catalysts provided higher conversions than the Zeolite-X type catalysts. The
increased conversions were attributed to the higher basicity of ETS-10 zeolites and larger
pore structures that improved intra-particle diffusion.
Research in the field of biological catalysts have also gain momentum recently and
used in the transesterification of different vegetable oils.Dehua Liu et al studied Candida
antarctica lipase catalysed biodiesel production of soyabean oil[47].The optimum
conditions of the transesterification were 30% enzyme based on oil weight; a molar ratio of
methyl acetate/oil of 12:1; temperature 40 °C and reaction time 10 h.
Effect of ultrasonication on the alkaline transesterification of Cynara cardunculus
L. seed oil with methanol for biodiesel production was investigated [48]. In this study it
was reported that the % yield of the extracted methyl esters using mechanical stirring was
lower compared to ultrasonication (50.4 and 85.1% respectively). Microwave irradiation
can also be used for the production of the biodiesel. Shakinaz T.ElSheltawy et al reported
the effect of microwave on the transesterification of jatropha oil[49]. The study showed
that the application of radio frequency microwave energy offers a fast, easy route to this
valuable biofuel with the advantages of enhancing the reaction rate (2 min instead of 150
min) and of improving the separation process.
26
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29
Chapter 3
MATERIALS AND METHODS
3.1 Materials
The petals and stamen of Nymphea nouchali, seeds of Pongamia pinnatta L,
Derris trifoliata and Canvalia cathartica, were collected from Kuttanadu wetland
ecosystem of southern Kerala, India. The seeds of Thespesia populnea were collected
from Koratty, Thrissur. Avicenia marina seeds were collected from Ayiramthengu,
Kollam. All the chemicals used were of analytical grade without further purification.
NaOH and KOH pellets were purchased from Merck India.
Nymphea nouchali Thespesia populnea Derris trifoliate
Pongamia pinnatta LCallophyllum inophyllum Canvalia cathartica
30
3.2 Methodology
3.2.1 Extraction of oil
The plant parts were dried under sunshade for one week. Powdered and extracted
with hexane at 850C for 2 hours in an automatic Soxhlet apparatus, SOX 3, Tulin
Equipments, Chennai. The solvent was removed from the extracts at 450C under vacuum
using a rotary evaporator to obtain crude oil samples. The available oil percentage in the
samples was determined.
Based on the oil yield and availability, Nymphea Nouchali,Calophyllum
Inophylum, Pongamia pinnata and Thespesia Populnea were selectedfor
transesterification studies.The oil samples were then kept in hot air oven at 105 0C for 2
hours in order to remove moisture
3.2.2 Determination the oil yield
The % oil yield was calculated as follows
Oil Content = [ (Weight of oil)/(Weight of sample)] × 100
Fig 5: Automatic soxhlet extractor
31
3.2.3 Determination of Free Fatty Acids
The FFA of oils was determined using the standard procedure. 25 ml of ethanol is
measured into conical flak, neutralised and boiled in a water bath in order to remove
dissolved gases. Approximately 2 g f the oil is transferred into the 25 ml of hot ethanol
with continues heating. A few drops of phenolphthalein indicator were added and titrated
aganist 0.1M NaOH .The end point is the appearance of permanent pink colour.
%��������������������� =� × � × 28.2
�× 100
V = Average volume of NaOH, M= Molarity of NaOH, 28.2g/mol = Molecular weight
of oleic acid, W= Weight of oil
3.2.4 Determination of fatty acid composition of oils
The various vegetable oils are distinguished by their fatty acid compositions. The
fatty acid composition of oils was determined by gas chromatography-mass
spectroscopy. Properties of biodiesel depend on the composition and percentage of fatty
acids in the oil. The fatty acids which are commonly found in vegetable oil and fat are
stearic, palmitic, oleic, linoleic. The other fatty acids which are also present in many of
the oils and fats are mysristic, palmitoleic, arachidic, linolenic and octadectetranoic.
There are many other fatty acids which are also found in oils with the above mentioned
common fatty acids.
The fatty acid composition of the seeds were determined by converting into fatty
acid methyl esters (FAMEs) followed by GC-MS. 0.25g sample was refluxed with 20ml
0.5 M methanolic KOH for 20 min at 55 0C, cooled and esterified with 1.5 ml H2SO4 and
15 ml methanol .The mixture is refluxed for 30 min, cooled to room temperature and 10
ml n-heptane was added, again refluxed for 10 min. The filtrate was transformed to a
32
separating funnel and shaken with 5 ml saturated NaCl. The top layer was collected
through anhydrous sodium sulphate and transferred to 2 ml autosampler vials for GC-MS
analysis. The methyl esters of fatty acid were separated by GC using a DB Wax column
.The compounds were detected by MS and identified by comparison with the NIST mass
spectral database (National Institute of Standards and Technology, Gaithersburg,
Maryland ,USA).
3.2.5 Transesterification of oils
Two step acid- base catalysed transesterification
A two step process, acid catalysed esterification process and followed by base-
catalysed transesterification process, were selected for converting oil samples to ethyl
esters of fatty acids. In order to reduce the FFA content in the oil, the oil was firstly
treated with acid to esterify the free fatty acids. The process was done to convert FFA to
esters using an acid catalyst (1% w/w Sulphuric acid) to reduce the FFA concentration of
the oil below 5%. Second step was base catalysed transesterification.
Acid pre-esterification
Pre-esterification was carried out in a 100 ml three-neck flask. The flask was
immersed in a glass water bath placed on the plate of magnetic stirrer of 400rpm.It was
confirmed that transesterification depends on several factors, namely, alcohol to oil ratio,
catalyst type, reaction time, FFA and water content of oils 8. In the present work, the
optimum condition for the reaction was found to be at 30:1 ethanol to oil molar ratio,
reaction temperature of 500C and reaction time of 2 hrs for Pongamiaoil.
Firstly, in the pre-esterification process, the solution of concentrated sulphuric
acid (1% based on oil weight) in alcohol was heated at 500C and then added into the
reaction flask. Ethanol to oil ratio was kept at 30:1 and reaction temperature at 500C. The
33
reaction was carried out for 2 hrs. The conversion of pre-esterification was calculated by
comparison of the acid values before and after the reaction.
Base catalysed transesterification
It was confirmed that transesterification depends on several factors, namely,
alcohol to oil ratio, catalyst type, reaction time, FFA and water content of oils. The acid
value of the oil was reduced after the acid pre treatment. The oil was preheated in a two
necked round bottomed flask at 500C for reducing its viscosity. The potassium
hydroxide-ethanol solution was prepared. The alkali ethoxide solution was added to
preheated oil while mixing by means of a magnetic stirrer. The stirring was maintained at
350 rpm throughout the reaction. The reaction was stopped after 2h and was poured into
a separating funnel and allowed to settle under gravity. The products of the alkaline
transesterification process result in the formation of two layers viz., an upper layer
containing biodiesel and a lower layer of glycerol. The lower layer was drained off. The
upper layer was washed with hot distilled water until the bottom aqueous layer becomes
clear.
Transesterification reaction with ultrasound
After the pre treatment of the oil, it was then subjected to ultrasound for
transesterification using base catalyst. The tub of ultra sound bath was filled with 300 ml
of distilled water and then the beaker containing the reactants was placed inside. The
temperature was maintained in 500C and the beaker was covered with aluminium foil,
considering that this temperature the evapouration of ethanol is negligible. The
equipment was set to operate at 200 W and 20 kHz for 20 minutes by keeping other
optimum reaction conditions and process parameters was unaltered.
34
CHAPTER 4
RESULTS AND DISCUSSION
4.1 Extraction of oil from of selected wetland plants
The plant parts were sun dried for one week and oven dried at 1200C for 2 hours.
The plant parts are then powdered in a blender and extracted with hexane at 85 0C for 2
hours in an automatic Soxhlet apparatus, SOX 3,Tulin Equipments, Chennai. The solvent
was removed from the extracts at 450C under vacuum using a rotary evaporator to obtain
crude oil samples. The available oil percentage in the samples was determined.
Plant Part used Oil yield (%)
Nymphea nouchali (Blue lotus) Petals and stamen 1.60
Canvalia cathartica Seeds 2.34
Derris trifoliata Seeds 5-7
Pongamia pinnatta Seeds 46.36
Thespesia populnea Seeds 22.59
Calophyllum inophyllum Seeds 36.60
Table 5 :The available oil percentage in the sample
4.2 Estimation of acid value and free fatty acid content (FFA)
4.2.1 Procedure for estimation of acid value
Weigh sufficient quantity of oil in an Erlenmeyer flask. Add 25 ml of freshly
prepared neutralized hot ethanol and 1ml of phenolphthalein indicator. Boil the mixture
for about 5min and titrate while as hot as possible with standard aqueous alkali solution
shaking vigorously during titration.
��������� =��. � × � × �
�
V= Volume in ml of standard KOH
N= Normality of standard KOH,0.1047N
W=weight in gram of oil
35
Table 6 : Acid value of oil
4.2.2 Procedure for estimation of FFA
Same procedure as Acid value
%��������� ������������ =� × � × ��. �
�× ���
%��������� ������������� =� × � × ��
�× ���
Table 7: FFA value of oil
The maximum acid value for alkaline transesterification is 2 mg KOH/g of oil
recommended by Canakci and Van Gerpen. Based on the acid value, the FFA content of
Nymphea nouchali is0.44% thus; it does not need any pre-treatment before
transesterification. Acid value and hence the free fatty acid content of other oils and they
have to be pretreated to reduce FFA.
Oil Acid Value
(mg KOH/ g)
Nymphea nouchali 0.624
Canvalia cathartica 23.64
Derris trifoliata 17.24
Pongamia pinnatta 7.02
Thespesia populnea 8.84
Callophyum inophyllum 15.92
Oil Free fatty acid Value (%)
Nymphea nouchali 0.44
Canvalia cathartica 15.85
Derris trifoliata 12.14
Pongamia pinnatta 4.96
Thespesia populnea 5.21
Callophyum inophyllum 11.22
36
4.3 Fatty acid profile of selected wetland plants
Table 8: Fatty acid composition of selected wetland plants was determined by gas chromatography-mass spectroscopy.
Systemic name Formula Structure Nymphea nouchali
Canvalia cathartica
Derris trifoliata
Pongamia pinnatta
Thespesia populnea
Octanoic C8H16O2 8:0 Trace 0.166
Decanoic C10H20O2 10:0 -----
2-methyl decanoic C11H22O2 10:0 7.6 0.113
Dodecanoic (Lauric acid) C12H24O2 12:0 3.386 3.700 trace 1.698
9(Z)-dodecenoic C12H22O2 12:1 0.161
9(E) – dodecenoic C17H32O2 12:1 0.691
Tetradecanoic(Myristic acid) C14H28O2 14:0 3.5 2.423 2.855 trace 1.536
Hexadecanoic (Palmitic acid) C16H32O2 16:0 4.05 22.04 26.27 7.0 33.315
9(Z)-heptadecenoic C17H32O2 17:1 0.738
9(E),12(E)- octadecadienoic C18H32O2 18:2 2.961 2.416
Octadecanoic(Stearic acid) C18H36O2 18:0 7.0 3.136
9(Z)- octadecenoic (Oleic acid) C18H34O2 18:1 55.7 46.480 42.78 69.0 17.192
9(E)-octadecenoic C18H34O2 18:1 1.273
9(Z),12(Z)-octadecadienoic (Linoleic acid)
C18H32O2 18:2 28.1 12.410 10.87 15.6 33.968
9(Z),15(Z)-octadecadienoic(Mangefiric acid)
C18H32O2 18:2 0.251
Linolenic acid 18:3 13.241 Trace trace Trace
Eicosanoic C20H40O2 20:0 0.652
37
The fatty acid composition of the oils from Thespesia populnea, Derris trifoliate,
Nymphea nouchali, Pongamia pinnatta and Canavalia Cathartica was determined using Gas
Chromatography- Mass Spectroscopy.
The seed oils contain a significant percentage of long chain polyunsaturated fatty acids
especially linoleic acid, oleic acid and α-linolenic acid (ALA). α-linolenic acid undergoes
desaturation and elongation to produce EPA (Eicosapentaenoic acid) and DPA
(Docosapentaenoic acid) in cell membranes is an important factor in determining cell and tissue
function[1]. It prevents inflammation, heart disease[2], stroke, type II diabetes, kidney disease
and certain types of cancers[3]. ALA is essential for the proper working of the nerve system[4].
Edible wild plants provide alpha linolenic acid more than by cultivated plants[5]. Derris trifoliate
contains an unusual fatty acid, cis 11-octadecenoic acid (42.27) as the major fatty acid. Cis-11-
octadecenoic was reported to be present in the seed oil of Doxantha unguis-cati [6]. It was
reported in the literature that some seed oils of Sapindaceae have cis-11-octadecenoic acid as the
principal fatty acid[7].
Thespesia oil contains high level of unsaturated fatty acids (52%), while the saturated
fatty acids accounts for remaining. The dominant unsaturated fatty acid is 9(Z), 12(Z)-
octadecadienoic acid (Linoleic acid) followed by oleic acid. The nutritional value of linoleic acid
was due to its metabolism at tissue levels which produces the hormone-like prostaglandin[8]. The
activity of these prostaglandins includes lowering of blood pressure and contraction of smooth
muscle. High levels of palmitic acid were also detected in the hexane extract of Thespesia
populnea. Lauric acid is an antimicrobial agent useful for infection control in hospitals. It was
already reported in the literature that, linoleic acid and oleic acid possessed potential antibacterial
activity and antifungal activity[9]. This property of Thespesia populnea oil is made use in the
Indian and Chinese folk medicine for the treatment of skin diseases, scabies and ringworm. It
also contains 9(Z), 15(Z)-octadecadienoic acid, a novel fatty acid reported only in the pulp of
mango.
38
Biodiesel fuel properties
Biodiesel properties Thespesia populnea
Pongamia pinnatta
Derris trifoliata
Saturated Fatty Acid 40.610 14.00 32.83
Mono Unsaturated Fatty Acid 18.310 69.01 42.78
Poly Unsaturated Fatty Acid 36.00 15.01 10.870
Degree of Unsaturation 90.310 100.20 64.52
Saponification Value (mg/g) 197.89 197.01 181.236
Iodine Value 81.67 90.30 58.15
Cetane number 55.513 53.685 63.330
Long Chain Saturated Factor 5.548 4.200 2.627
Cold Filter Plugging Point (°C) 0.955 -3.28 -8.224
Cloud Point (°C) 12.532 -1.310 8.826
Pour Point (°C) 6.783 -8.24 2.760
Allylic Position Equivalent 90.310 100.20 64.52
Bis-Allylic Position Equivalent 37.30 15.600 10.870
Oxidation Stability (h) 5.866 10.150 13.440
Higher Heating Value 37.316 39.021 34.001
Kinematic Viscosity (mm2/s) 3.422 3.913 3.133
Density (g/cm3). 0.831 0.864 0.755
Table: 9 - Biodiesel fuel properties are predicted based on fatty acid profile of oil feedstock
determined by gas-chromatography using Biodiesel Analyzer analytical software
39
Biodiesel fuel properties
Biodiesel properties Canvalia
cathartica Nymphea Nouchali
Biodiesel standard (ASTM method)
Saturated Fatty Acid 27.85 15.15
Mono Unsaturated Fatty Acid 46.49 55.70
Poly Unsaturated Fatty Acid 28.24 28.20
Degree of Unsaturation 102.96 112.10
Saponification Value (mg/g) 212.28 208.87
Iodine Value 105.21 101.19 <120
Cetane number 48.33 49.66 48-65
Long Chain Saturated Factor 2.20 0.405
Cold Filter Plugging Point (°C) -9.55 -15.205
Cloud Point (°C) 6.60 -2.86
Pour Point (°C) 0.35 -9.92 -15 to 10
Allylic Position Equivalent 102.97 112.10
Bis-Allylic Position Equivalent 41.48 28.20
Oxidation Stability (h) 6.77 6.77 > 3 hours
Higher Heating Value 40.33 38.82
Kinematic Viscosity (mm2/s) 3.723 3.46 1.9-6.0
Density (g/cm3). 0.900 0.870 0.86-0.90
Table 10: Biodiesel fuel properties are predicted based on fatty acid profile of oil feedstock determined by gas-chromatography using Biodiesel Analyzer analytical software
40
4.4 Transesterification Studies
4.4.1 Alkali-catalysed transesterification studies of Nymphaea nouchali (egyptian blue
lotus) oil
Nymphaea nouchali, often known by its synonym Nymphaea caerulea, or by
common names blue lotus. It is native to southern and eastern parts of Asia, and is the
national flower of Sri Lanka and of Bangladesh. Nymphaea nouchali is widely
distributed along the south-western coast of kerala. However, taking into account the
magnitude of its abundance, the studies conducted are still negligible. In the present
study petals and stamen of Nymphaea nouchali is screened for its potential for biodiesel
production.
Nymphaea nouchali Dried petals and stamen
Two major factors affecting the rate and conversion efficiency of
transesterification are: molar ratio of alcohol to oil and reaction temperature. When
Calophyllum inophyllum oil was processed by base catalysed reaction, the optimum
reaction conditions was 8:1 M ratio of methanol to oil and 60 0C reaction temperature. In
the present experiment, the catalyst concentration was kept at 1% of the lotus oil. KOH
was used as the catalyst.
Experimental Set Up: The oil was preheated in a two necked round bottomed flask at
500C for reducing its viscosity. The potassium hydroxide-ethanol solution was prepared.
The alkali ethoxide solution was added to preheated oil while mixing by means of a
41
magnetic stirrer. The stirring was maintained at 350 rpm throughout the reaction. The
reaction was stopped after 2h and was poured into a separating funnel and allowed to
settle under gravity. The products of the alkaline transesterification process result in the
formation of two layers viz., an upper layer containing biodiesel and a lower layer of
glycerol. The lower layer was drained off. The upper layer was washed with hot distilled
water until the bottom aqueous layer becomes clear.
The density of oil decreased on transesterification. The acid value of the oil was
reduced after transesterification. The alcohol to oil molar ratio is one of the most
important variables affecting the ester yields. In the present work, the ethanol to oil
molar ratio varied from 4:1 to 10:1.Fig.Shows the effect of ethanol to oil molar ratio on
yield of biodiesel at different temperatures. It was observed that the yield of biodiesel
increased with increase in molar ratio. But at molar ratio of 12:1and above, the yield of
biodiesel decreased with increase in the molar ratio. The molar ratio of 6:1 gave the
maximum yield of 89%.
Figure 6: Optimization of reaction conditions of Nymphea nouchali
42
Alcohol: Oil molar ratio Reaction
temperature % (v/v)Yield
6:1
50 78
60 89
70 80
9:1
50 70
60 72
70 70
4:1
50 55
60 60
70 56
Table 11: Optimization of reaction conditions of Nymphea nouchali
Transesterification studies were carried out at different reaction temperature such
as 50, 60 and 70 0C with 1%KOH for a reaction time of 2 h. The yield of biodiesel shows
an increasing trend with increase in reaction temperature up to 60 0C. This is because
higher reaction temperature helps in faster settlement of glycerol. The decrease in the
biodiesel yield beyond 60 0C may be due to saponification of the triglycerides before the
completion of the transesterification.
4.4.2 Two- step biodiesel production ofPongamia Pinnatta Seed Oil
Pongamia pinnata (Derris indica , Indian Beech Tree, Honge Tree, Pongam Tree,
Milletia pinnata) is widely distributed in India. It belongs to mangrove associated plants.
It contains more than 40% oil yield and it varies with different locations.
43
Experimental Set Up:
Acid pre-esterification
Pre-esterification was carried out in a 100 ml three-neck flask. The flask was
immersed in a glass water bath placed on the plate of magnetic stirrer of 400 rpm. It was
confirmed that transesterification depends on several factors, namely, alcohol to oil ratio,
catalyst type, reaction time, FFA and water content of oils .Firstly, in the pre-
esterification process, the solution of concentrated sulphuric acid (1% based on oil
weight) in alcohol was heated at 500C and then added into the reaction flask. Ethanol to
oil ratio was kept at 30:1 and reaction temperature at 500C. The reaction was carried out
for 2 hrs. The conversion of pre-esterification was calculated bycomparison of the acid
values before and after the reaction.
Base catalysed transesterification
It was confirmed that transesterification depends on several factors, namely,
alcohol to oil ratio, catalyst type, reaction time, FFA and water content of oils. The acid
value of the Pongamia oil was reduced to 1.04mg KOH/g after the acid pre treatment.
The oil was preheated in a two necked round bottomed flask at 500C for reducing its
viscosity. The potassium hydroxide-ethanol solution was prepared. The alkali ethoxide
solution was added to preheated oil while mixing by means of a magnetic stirrer. The
stirring was maintained at 350 rpm throughout the reaction. The reaction was stopped
44
after 2h and was poured into a separating funnel and allowed to settle under gravity. The
products of the alkaline transesterification process result in the formation of two layers
viz., an upper layer containing biodiesel and a lower layer of glycerol. The lower layer
was drained off. The upper layer was washed with hot distilled water until the bottom
aqueous layer becomes clear.
In the present work ,the ethanol to oil molar ratio varied from 6:1 to
12:1.Fig..Shows the effect of ethanol to oil molar ratio on yield of biodiesel at different
temperatures. It was observed that the yield of biodiesel increased with increase in molar
ratio. But at molar ratio of 12:1and above, the yield of biodiesel decreased with increase
in the molar ratio. The molar ratio of 9:1 at 50 0C gave the maximum yield of 86%.
Transesterification studies were carried out at different reaction temperature such
as 40, 50 and 60 0C with 1%KOH for a reaction time of 2 h. The yield of biodiesel shows
an increasing trend with increase in reaction temperature up to 50 0C. This is because
higher reaction temperature helps in faster settlement of glycerol. The decrease in the
biodiesel yield beyond 50 0C may be due to saponification of the triglycerides before the
completion of the transesterification. This finally results in the formation of an emulsion
and makes the separation of layers difficult.
Effect of acid pre treatment on the acid value
45
Acid value
Before pre esterification 7.02 mg KOH/g
After esterification 1.04 mg KOH/g
Transesterification of Pongamia pinnatta oil
Alcohol:Oil molar ratio
Reaction temperature % (v/v)Yield
6:1
40 42
50 55
60 32
9:1
40 71
50 86
60 40
12:1
40 42
50 50
60 36
Table 11: Optimization of reaction conditions of Pongamia pinnatta
4.4.3 Two- step biodiesel production ofThespesia Populnea oil
30
40
50
60
70
80
90
40 45 50 55 60
Bio
die
sel y
ield
(%)
Reaction temperature (0C)
6:01
9:01
12:01
Thespesia populnea, commonly known as the Portia tree is species of flowering
plant in the mallow family, Malvaceae.
Experimental set up
Pre-esterification was carried out in a 100 ml three
immersed in a glass water bath placed on the plate of magnetic stirrer of 400 rpm. It was
confirmed that transesterification depends on several factors, name
catalyst type, reaction time, FFA and water content of oils .Firstly, in the pre
esterification process, the solution of concentrated sulphuric acid (1% based on oil
weight) in alcohol was heated at 50
oil ratio was kept at 30:1 and reaction temperature at 50
for 2 hrs. The conversion of pre
values before and after the reaction.
46
Thespesia populnea, commonly known as the Portia tree is species of flowering
plant in the mallow family, Malvaceae.
esterification was carried out in a 100 ml three-neck flask. The flask was
immersed in a glass water bath placed on the plate of magnetic stirrer of 400 rpm. It was
confirmed that transesterification depends on several factors, namely, alcohol to oil ratio,
catalyst type, reaction time, FFA and water content of oils .Firstly, in the pre
esterification process, the solution of concentrated sulphuric acid (1% based on oil
weight) in alcohol was heated at 500C and then added into the reaction flask. Ethanol to
oil ratio was kept at 30:1 and reaction temperature at 500C. The reaction was carried out
for 2 hrs. The conversion of pre-esterification was calculated by comparison of the acid
values before and after the reaction.
Thespesia populnea, commonly known as the Portia tree is species of flowering
neck flask. The flask was
immersed in a glass water bath placed on the plate of magnetic stirrer of 400 rpm. It was
ly, alcohol to oil ratio,
catalyst type, reaction time, FFA and water content of oils .Firstly, in the pre-
esterification process, the solution of concentrated sulphuric acid (1% based on oil
action flask. Ethanol to
C. The reaction was carried out
esterification was calculated by comparison of the acid
47
The oil was preheated in a two necked round bottomed flask at 500C for reducing
its viscosity. The potassium hydroxide-ethanol solution was prepared. The alkali
ethoxide solution was added to preheated oil while mixing by means of a magnetic
stirrer. The stirring was maintained at 350rpm throughout the reaction. The reaction was
stopped after 2h and was poured into a separating funnel and allowed to settle under
gravity. The products of the alkaline transesterification process result in the formation of
two layers viz., an upper layer containing biodiesel and a lower layer of glycerol. The
lower layer was drained off. The upper layer was washed with hot distilled water until
the bottom aqueous layer becomes clear.
Alcohol: Oil molar ratio Reaction temperature % (v/v)Yield
6:1
40 50
50 65
60 87
70 85
9:1
40 52
50 72
60 85
70 80
12:1
40 50
50 66
60 80
70 72
Table 12: Optimization of reaction conditions of Thespesia populnea
48
Figure 8: Optimization of reaction conditions of Thespesia populnea
In the present work, the ethanol to oil molar ratio varied from 6:1 to 9:1.Fig. shows
the effect of ethanol to oil molar ratio on yield of biodiesel at different temperatures. It was
observed that the yield of biodiesel increased with increase in molar ratio. The molar ratio
of 6:1 gave the maximum yield of 87% at 60 0C Transesterification studies were carried
out at different reaction temperature such as 40, 50 and 60 0C with 1%KOH for a reaction
time of 2 h.
4.5 Effect of ultrasound on transesterification of oils
The tub of ultra sound bath was filled with 300 ml of distilled water and then the
beaker containing the reactants was placed inside. The temperature was maintained in 500
C and the beaker was covered with aluminium foil, considering that this temperature the
evapouration of ethanol is negligible. The equipment was set to operate at 200 W and 20
kHz for 10, 20 and 30 minutes by keeping other optimum reaction conditions and process
parameters was unaltered. It was found that transesterification using ultrasound drastically
reduce the reaction time and leads to higher yields of biodiesel greater than 90 %.
30
40
50
60
70
80
90
35 45 55 65 75
%Y
ield
Reaction time
06:01
09:01
12:01
49
Table 13: Effect of ultrasound in transesterification
The percentage yield of biodiesel increases with the application of ultrasound to
the system. At a reaction time of 20 minutes it gave a good yield (>90 %) than the
conventional method of transesterification. Thus it works better than conventional
methods, as it saves time, has high extraction efficiency and a low environmental impact.
In biodiesel production, adequate mixing is required to create su cient contact between
the vegetable oil or animal fat and alcohol, especially at the beginning of the reaction.
Application of ultrasonication provides sufficient mixing. Ultrasonic cavitation and
microbubble formation, which are caused by the ultrasonic energy introduced by the
sonotrode, greatly improve the interfacial contact between the immiscible methanol and
plant oil/ animal fat mixture, thus increasing the reaction rate. Also, the formation and
bursting of microbubbles caused by ultrasonic cavitation intensifies the local energy
transfer and energizes the reactant molecules, thus enhancing the overall reaction rate.
Thus the remarkable decrease in the reaction time can be explained by intense mass
transfer afforded by the unique conditions generated by cavitation noise.
Oil Ultrasound reaction
time (minutes) % (v/v)Yield
Nymphea oil 10 85 20 89 30 >90
Pongamia 10 90 20 94 30 94
Thespesia 10 89 20 90 30 >95
50
References
1. Burdge, G.C., A.E. Jones, and S.A. Wootton, Eicosapentaenoic and docosapentaenoic
acids are the principal products of α-linolenic acid metabolism in young men. British
Journal of Nutrition, 2002. 88(04): p. 355-363.
2. De Lorgeril, M., et al., Mediterranean alpha-linolenic acid-rich diet in secondary
prevention of coronary heart disease. The Lancet, 1994. 343(8911): p. 1454-1459.
3. Abd El-Gleel, W. and M. Hassanien, Antioxidant properties and lipid profile of
Diplotaxis harra, Pulicaria incisa and Avicennia marina. Acta Alimentaria, 2012. 41(2):
p. 143-151.
4. Holman, R., S. Johnson, and T. Hatch, A case of human linolenic acid deficiency
involving neurological abnormalities. The American Journal of Clinical Nutrition, 1982.
35(3): p. 617-623.
5. Simopoulos, A.P., Omega-3 fatty acids and antioxidants in edible wild plants. Biological
Research, 2004. 37(2): p. 263-277.
6. Chisholm, M.J. and C. Hopkins, Fatty acids of Doxantha seed oil. Journal of the
American Oil Chemists’ Society, 1965. 42(1): p. 49-50.
7. Spitzer, V., Fatty acid composition of some seed oils of the Sapindaceae.
Phytochemistry, 1996. 42(5): p. 1357-1360.
8. Belury, M.A., Dietary conjugated linoleic acid in health: Physiological effects and
mechanisms of action 1. Annual review of nutrition, 2002. 22(1): p. 505-531.
9. Huang, W.-C., et al., Anti-bacterial and anti-inflammatory properties of capric acid
against Propionibacterium acnes: A comparative study with lauric acid. Journal of
dermatological science, 2014. 73(3): p. 232-240.
51
CHAPTER 5
CONCLUSION
The present study revealed that Thespesia populnea seeds and Pongamia pinnatta
seeds yield a high content of oil, 22.59% and 46.36% w/w respectively. The biodiesel
derived from these oils meet the international standards. The optimum biodiesel yield
from thespesia oil was 87% at alcohol:oil molar ratio of 6:1, reaction time for 2 hours at
600C and for pongamia pinnatta was 86% at alcohol:oil molar ratio of 9:1, reaction time
of 2 hours at 500C. Pongamia oil with high free fatty acid content affected the catalytic
activity of the alkali process negatively, resulting in saphonification which decreases the
esters yield and causing processing problems. Pongamia oil has to be pre esterified using
acid before subjecting to base catalysed transesterification.
The sonolysis of oil showed considerable gain in the reaction time with respect to
classical transesterification. The remarkable decrease in the reaction time can be
explained by intense mass transfer afforded by the unique conditions generated by
cavitation noise. Thus biodiesel production using ultrasound could be considered as a
potential route for the production of biodiesel, capable of meeting high demands in short
time period, with energy costs that may be less than the expenses with the conventional
method.
The identified fatty acids in the hexane extract of Thespesia populnea, Derris
trifoliate and Canavalia cathartica exhibit multifunctional biological activity. The oil of
these seeds contained a significant percentage of pharmacologically active linoleic and
alpha-linolineic fatty acids. The present findings also proved the traditional use of these
plants in the folk medicine.
52
In the present study, six wetland species of Kuttanad region were selected and
investigated for screening their potential for biodiesel production.The fatty acid
compositions of plants were studied by Gas Chromatography – Mass Spectroscopy.
Among them thespesia and pongamia were identified as a cheap and renewable raw
material for biodiesel production.
53
RESULTS OF GC-MS
54