Assessment of the potential of methyl ester production from non-edible oils


Doctoral Thesis / Dissertation, 2017
236 Pages, Grade: A

Excerpt

CONTENTS

ABSTRACT

LIST OF TABLES

LIST OF FIGURES

Chapter-1 INTRODUCTION

Chapter-2 LITERATURE REVIEW
TABLE FORMAT

Chapter-3 EXPERIMENTAL METHODOLOGY

Chapter-4 RESULTS AND DISCUSSION
4.1 Production and comparison of methyl esters from uco, Cottonseed oil, Jatropha oil and Neem oil using enzymatic and acid-alkaline transesterification at optimized parameters
4.1.1 Enzymatic(lipase) transesterification
4.1.2 Acid-alkaline transesterification
4.1.3 Comparison between Enzyme-catalyzed and Acid- alkaline catalyzed transesterification methods
4.2 Screening of methyl esters of uco & Jatropha
4.3 Optimization of process parameters using a factorial design and a surface response design
4.3.1 Used Cooking Oil Methyl Ester(UCOME)
4.3.2 Jatropha Methyl Ester
4.4 Gas Chromatographic analysis of fatty acid methyl ester4.5 Predicting biodiesel properties by fatty acid methyl esters composition of oil
4.6 Elemental analysis
4.7
Fourier Transform Infrared Spectroscopy (FTIR) analysis4.8 Performance and Emissions Characteristics
4.9 Cost analysis
NOMENCLATURE

Appendix-A MODEL CALCULATIONS

Appendix-В EXPERIMENTAL AND CALCULATED DATA

PUBLICATIONS

CERTIFICATE

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This is to certify that the research work incorporated in this Doctoral Thesis entitled “Assessment of the Potential of Methyl ester Production from non-edible oils”, is carried out by Mr. B. Venu Gopal under my guidance for the award of the Degree of ‘Doctor of Philosophy’ in the Faculty of Chemical Engineering and Chemical Technology, Andhra University College of Engineering (A), Visakhapatnam, Andhra Pradesh, India.

(Prof. V. SRIDEVI)

Research Director

Department of Chemical Engineering,
Andhra University,
Visakhapatnam.

DECLARATION

I hereby declare that the work presented in this dissertation entitled “Assessment of the Potential of Methyl ester Production from non-edible oils”, has been carried out by me under the guidance of Prof. V. Sridevi, Department of Chemical Engineering, Andhra University College of Engineering (A), Andhra University, Visakhapatnam. The work embodied in this thesis is original and it has not been submitted in part or in full for any other degree or diploma of this or any other university.

(B. Venu Gopal)

Acknowledgement

I greatly indebted to Andhra University College of Engineering that has provided me with the healthy environment to drive me to achieve my ambition and goal.

With profound respect, I wish to express my deep sense of gratitude to Professor V. Sridevi, Department of Chemical Engineering, and AUCE(A) for allowing me into the field of research, who inspired me with her words filled with dedication and discipline towards work. I am deeply indebted for her valuable guidance and timely suggestions.

I convey my deep and sincere thanks to Professor s. V. Naidu (Head of the Department) and Professor p. Raj endra Prasad Chairman, Board of studies and Professor V. Sujatha, faculty Chairman, Department of Chemical Engineering for extending their support and cooperation in providing access to facilities of the Department.

I am grateful and deeply indebted to Associate Professor P.V.Rao mechanical engineering for his valuable suggestions and guidance during my project and career.

I convey my deep respect to the professors R. Padma Sree, K.V.Ramesh, Pulipati king for their constant encouragement, I thank assistant professor M. Deepa, Dr N. M. Yugandhar, Dr Ch. A. I. Raju and Dr M. Tukaram Bai for their kind cooperation in making my project work a success.

I am grateful to all the faculty members and non- teaching staff for their Co- Operation.

I am thankful for Mechanical engineering laboratory, Andhra University for co-operation in my work.

I affectionately appreciate the help and encouragement received from my friends, research scholars and M.tech Students

I always express my love, affection and heartfelt thanks to my family. So, I want to dedicate all my works to my father B. Jagadeeswar rao gam, my mother B. Lakshmi gam, my sisters Sandhya, Krishna Priya, Sukanya and all family members who encouraged me and supported me in all aspects for accomplishing my works.

(B. Venu Gopal)

ABSTRACT

Biodiesel as an alternative fuel for diesel engines is becoming increasingly important due to diminishing petroleum reserves and the environmental consequences of exhaust gases from petroleum-fueled engines. Biodiesel, which is made from renewable sources, consists of the simple alkyl esters of fatty acids. As a future prospective fuel, biodiesel has to compete economically with petroleum diesel fuels. A two-step transesterification process (Sequential esterification and transesterification process) was used to prepare methyl ester (biodiesel) from high free fatty acid (FFA) content oils. For the yield of high FF A, two-step acid-base catalyzed method has been developed which consists of acid-catalyzed pretreatment/esterification step to reduce the FFA to less than 1% using H2SO4 as an acid catalyst and transesterification of pretreated oil to biodiesel using alkali catalyst. In the present study, the main focus is being placed to explore the non-edible oil resources like Used Cooking Oil (UCO), Cottonseed oil, Jatropha (.Jatropha curcas) oil, Neem(Azadirachta indica) oil as a potential source for biodiesel. Experimental results from enzyme (lipase) catalyzed method for selected oils using influencing parameters such as reaction time and catalyst weight, experimental results from acid-alkaline catalyzed methods using common influencing parameters such as methanol to oil molar ratio, catalyst weight, reaction temperature and reaction time for above-mentioned oils were compared using batch mode. Methyl ester (biodiesel) yield range of 66.20-71.6% was attained for an enzyme-catalyzed method, whereas for acid- alkaline the yield range was 84.4-91.6%. This gives the indication of further refinement in the enzyme-catalyzed transesterification process. However, enzyme-catalyzed biodiesel production has some limitations especially when implemented in industrial scale because of the high cost of enzyme, low reaction rate and enzyme deactivation. As the catalyst, an enzyme is restricted to rigorous reaction condition and the activity loss of lipase. The influencing parameters and absolute results of the analysis give the impression of the superiority of acid-alkaline transesterification method for methyl ester production. In this study, we have selected Used Cooking Oil Methyl Ester (UCOME) and Jatropha Methyl Ester (JME) among the methyl esters of four oils. The main reasons are the Jatropha oil gives the highest yield of methyl ester(91.6%) and UCO demonstrates the high potential of producing economically viable methyl ester(89.5%) from low-cost feedstocks.

The process parameters were optimized using Response Surface Methodology (RSM). The statistical models developed by UCOME and Jatropha ME for predicting yield showed a good agreement between the experimental and calculated values(> 0.9423 & > 0.9323). The value of regression coefficient R[2] for the model from UCOME and Jatropha ME is 0.9711 & 0.9631, indicating the good fitness of the model.

The fatty acid methyl esters content in the reaction mixture were quantified by Gas Chromatography-Mass Spectroscopy(GC-MS) and c H N o s was analyzed using elemental analyzer and are compared with the biodiesel standards (ASTM D6751). The functional groups of the methyl ester were investigated using Fourier Transforms Infrared Spectroscopy (FTIR). Physical and chemical properties of methyl ester are influenced by the structural features of fatty acid, such as with saturated, monounsaturated and polyunsaturated fatty acids and characterized by its density, kinematic viscosity, flash point, molecular weight, cetane number, iodine value, cloud and pour points, calorific/heating value of the biodiesel according to ISO norms and are compared to that of petroleum diesel.

Further, the performance and emission characteristics of Methyl Ester(ME) from uco & Jatropha oil were assessed in an internal combustion engine. Tests were carried out for analyzing various parameters such as the performance of brake thermal efficiency, emissions of CO, HC and ΝΟχ gases in the exhaust. The brake thermal efficiency of both

the oils was lower than diesel. However, CO and HC were found to be lower with UCOME & Jatropha ME as compared to diesel, while NOx emissions on both the oils were higher than diesel. In view of comparable engine performance and reduction in most of the engine emissions, it can be concluded that methyl ester derived from high FFA content UCO & Jatropha oil could be a good substitute to diesel fuel in a diesel engine in the near future as far as decentralized energy production is concerned. The economic feasibility study indicates that the cost of methyl ester derived from UCOME is the cheapest (Rs. 74.8 per litre) compared to the Jatropha ME (Rs. 92.9 per litre), but higher than the diesel cost. (Rs. 69.43 per litre). In conclusion, through appropriate setting of process parameters economically viable methyl ester(biodiesel) could be produced from uco which comes under low-cost feedstocks that would substitute or combine with petroleum-based diesel to meet the ever-increasing demand of fuel oil.

Keywords: High FFA content oils, transesterification, methyl ester, RSM, GC-MS, FTIR, performance, emission characteristics and cost analysis.

LIST OF FIGURES

CHAPTER-1

1.1 Biodiesel bus

1.2 Enzymatic Biodiesel Production by Transesterification with Methyl Acetate

1.3 Transesterification of Triglycerides with a base catalyst

CHAPTER-3

3.1 Schematic diagram of the production of biodiesel by acid- alkali and enzymatic transesterification of high FFA content oils

3.2 Experimental setup for transesterification

3.3 Aspergillus niger

3.4 Preconditioning of oil

3.5 Transesterification reaction

3.6 Glycerin is separated from the methyl ester

3.7 Methyl esters of uco, Cottonseed, Jatropha and Neem

3.8 Agilent 6890 GC, 5973 MSD

3.9 Elemental analyzer

3.10 Redwood Viscometer

3.11 Cloud and pour point apparatus refrigerated

3.12 IC Engine(Kirloskar) and AVE Gas analyzer

CHAPTER-4

4.1 Effect of reaction time(hr) on methyl ester yield at optimum conditions(4:lmethanol to oil molar ratio, temperature 35°C)

4.2 Effect of catalyst weight on methyl ester yield at optimum conditions (4:lmethanol to oil molar ratio, temperature 35°C)

4.3 Effect of Methanol to Oil molar ratio on methyl ester yield

4.4 Effect of catalyst weight on methyl ester yield

4.5 Effect of temperature on methyl ester yield

4.6 Effect of reaction time on methyl ester yield

4.7 Predicted versus actual FAME yield

4.8 Normal probability plot of the residual

4.9(a) A surface plot of methanol oil ratio and catalyst weight against methyl ester yield

4.9(b) A surface plot between methanol oil ratio and time against methyl ester yield

4.9(c) A surface plot between catalyst weight and temperature against methyl ester yield

4.10 Predicted versus actual FAME yield

4.11 Normal probability plot of the residual

4.12(a) A surface plot of catalyst weight and methanol oil molar ratio against methyl ester yield

4.12(b) A surface plot between reaction time and methanol oil molar ratio against methyl ester yield

4.12(c) A surface plot between reaction time and catalyst weight against methyl ester yield

4.13 GC- 5973 N MSD Analysis for methyl ester of uco

4.14 GC- 5973 N MSD Analysis for methyl ester of Jatropha oil

4.15 Infrared Spectra of Used Cooking Oil methyl ester

4.16 Infrared Spectra of Jatropha methyl ester

4.17 Variation of brake thermal efficiency with brake power

4.18 Variation of NOx emissions with brake power

4.19 Variation of CO emissions with brake power

4.20 Variation of HC emissions with brake power

LIST OF TABLES

CHAPTER-1

1.1 Production of BD from edible, non-edible oil and animals fats in different Countries

1.2 The general breakdown of biodiesel production cost

1.3 Properties of crude cottonseed oil

1.4 The fatty acid composition of cottonseed oil

1.5 Properties of crude Jatropha curcas oil

1.6 The fatty acid composition of crude Jatropha curcas oil

1.7 Properties of crude neem oil

1.8 The fatty acid composition of crude neem oil

1.9 Properties of uco (palm oil)

1.10 The fatty acid composition of crude palm oil

CHAPTER-3

3.1 Advantages and disadvantages of Methods of transesterification

3.2 Sources of Feed Stock

3.3 The composition of lipase production medium

3.4 Independent Variables and Levels Used For Response Surface Design (UCO)

3.5 Independent Variables and Levels Used For Response Surface Design (Jatropha oil)

3.6 Saturated Fatty Acids in different oils

3.7 Some Unsaturated Fatty acids in food fats and oils

3.8 Engine specifications

3.9 Technical Specifications of Exhaust Gas Analyzer

CHAPTER-4

4.1 A comparative study of Enzymatic(Lipase) and Acid- alkaline catalyzed transesterification of methyl esters of uco, Cottonseed, Jatropha and Neem oil at optimized parameters

4.2 Optimized parameters of methyl esters

4.3 Experimental set up for 2-level-4-factor response surface design and the experimental and predicted values for biodiesel production from uco

4.4 Analysis of variance(ANOVA) for the fitted quadratic polynomial model

4.5 Experimental set up for 2-level-4-factor response surface design and the experimental and predicted values for biodiesel production from Jatropha

4.6 Analysis of variance(ANOVA) for the fitted quadratic polynomial model

4.7 The fatty acid composition of UCOME

4.8 The fatty acid composition of Jatropha Methyl Ester

4.9 Comparision of fatty acid composition with UCOME and Jatropha methyl ester

4.10 Percentage of saturated (SFA), monounsaturated (MUFA), polyunsaturated (PUFA) and total unsaturated (MUFA+ PUFA) fatty acid of each type of oil

4.11 Comparison of Elemental composition and ‘C/H' Ratio with Petrodiesel and Biodiesel

4.12 Physical and Chemical properties of test fuels in comparison to some ASTM biodiesel standards

4.13 FTIR Studies of Jatropha methyl ester

4.14 FTIR Studies of Used Cooking Oil methyl ester

4.15 Cost analysis of UCOME

4.16 Cost analysis of Jatropha ME

CHAPTER-1 INTRODUCTION

This chapter focused on a brief overview of the production of biodiesel from high free fatty acid content oils, selection of process, selection of alcohol and catalyst used is given here, the motivation of research work, objectives, rationale and significances are presented.

1.1 Introduction

Energy consumption is inevitable in human existence. Man relies immensely on it for various sectors of life like transportation, power generation, industrial processes, and residential consumption. World energy consumption doubled between 1971 and 2001 and the world energy demand will increase 53% by the year 2030. It is estimated that petroleum consumption will rise from 84.4 to 116 million barrels per day in the USA until the year 2030 [1]. Petroleum-based fuels are limited reserves concentrated in certain regions of the world. These sources are on the verge of reaching their peak production. The fossil fuel resources are shortening day by day. At the same time, its consumption rate is pacing at an alarming rate. The world currently faces an energy crisis. The global fossil fuel prices have been increasing dramatically way beyond the imaginations of common men. The scarcity of known petroleum reserves will make renewable energy sources more attractive. Also, the extensive use of fossil fuels has led to various environmental problems including pollution, increase in the amount of C02 and other greenhouse gases in the atmosphere, global warming etc. The depletion of fossil fuel has forced the mankind to find alternate ways of energy generation which is renewable, environmentally friendly and technically suitable for conventional engines without any modifications. Among the various alternatives biofuels especially biodiesel stands out as a promising method. Historically, it is believed that Rudolf Diesel himself started research with respect to the use of vegetable oils as fuel for diesel engines [2]. In the following decades, the studies became more systematic and, nowadays, much is known about its use as fuel. Despite being energetically favourable, the direct use of vegetable oils in fuel engines is problematic. Due to their high viscosity (about 11 to 17 times higher than diesel fuel) and low volatility, they do not burn completely and form deposits in the fuel injector of diesel engines. In Rudolph Diesel's 1893 paper "The Theory and Construction of a Rational Heat Engine," the German inventor described a revolutionary engine in which air would be compressed by a piston to a very high pressure thereby causing a sufficiently high temperature to ignite non-volatile oils. His first working engine could run on various vegetable oils, leading him to envision in 1911 that "the diesel engine can be fed with vegetable oils and will help considerably in the development of the agriculture of the countries which use it” [3]. Since then nearly all research has focused on how to improve the performance of the engine when using biologically based diesel fuel. Biodiesels are produced by the transesterification reaction of long chain fatty acids by alcohols, primarily methanol or ethanol, in presence of catalysts [4]. The direct use of alcohols as fuel causes corrosion of various parts in the engine. The transesterification process solves this problem. Vegetable oils are the primary source of biodiesel. They can be of edible or non-edible nature. Edible oils like coconut oil, soybean oil, sesame oil, palm oil, sunflower oil, rapeseed oil, canola oil can be used. Non-edible oils include neem oil, Pongamia oil, rubber seed oil, Jatropha oil, etc. In addition to these used oils can also be used for biodiesel production which is more economical. Oils of animal origin derived from sheep and beef tallow, fish oil etc also serve as a source of biodiesel. Biodiesel fuels are attracting increasing attention worldwide as a blending component or a direct replacement for diesel fuel in vehicle engines and which can be used in diesel engines after some adjustments and modifications.

1.2 Biofuel

In the recent years, declining reserves of fossil fuels, severe environmental pollution, fluctuating petroleum price and global warming have increased the quest for an alternative fuel. About one, third of the total energy consumption is towards transportation sector and of which 80% is towards road transportation by using liquid fuels such as petrol and diesel. The only way to overcome the quest is to rely on renewable energy resources such as sunshine, wind, thermal, biomass and flowing water.

Biomass can be re-grown seeds or plant parts as long as solar energy, soil nutrients and a source of water exist. For this reason, biomass is recognized as a renewable source of energy. In recent years global interest in renewable energy production has significantly increased due to being eco-friendly and is seen as a means of helping to reduce global warming by displacing the use of fossil fuels[5]. However, to be considered as a sustainable source, the input of energy required or biomass production must not exceed the output or amount of energy that can be extracted from the biomass. Due to its renewable, biodegradable, nontoxic and environmentally beneficial characteristics, biofuel has the potential of reducing dependence on petroleum, improving environmental quality, lowering the number of emissions produced by human activities such as greenhouse gases (GHG), promoting rural development and providing job opportunities.

The search for alternative fuels has triggered many large-scale investors to focus on the development of methods for production of biofuels. Countries like US, South East Asia, Europe, Brazil and India have invested in the production of alternative fuels from corn, soybean, palm, rapeseed, sugarcane and Jatropha. Brazil uses 20 percent of pure ethanol along with fossil fuels for their vehicles whereas the countries such as the United States and Australia use a 10% ethanol blend. National Biodiesel Mission of India has planned to meet 20 percent of the country’s diesel requirements using biodiesel produced from Jatropha oil. The two Indian firms namely Natural bioenergy Limited (NBL) in collaboration with two other firms namely Energea GMBH (Austria) and Fe clean Energy and Southern Online Biotech have planned to produce biodiesel at an estimate of about 300 tonnes/day (90,000 tonnes/year) and 30 tonnes/day respectively in Andhra Pradesh, India. European Union used 2% blended biofuel in 2005 and raised the blending ratio to 5.75% in 2010. Due to short supply of edible vegetable oils, they cannot be used for biofuel production and hence the government of India has decided to use non-edible oil from Jatropha curcas seeds as a biodiesel feedstock.

Biofuel policies and mandates

Biofuel programs have proliferated around the world in recent years, whether motivated by a desire to bolster agricultural industries or achieve energy security or reduce GHG emissions or improve urban air quality. The growth of ethanol output in the US, derived mainly from com (maize), has been driven by fiscal incentives (e.g., tax, subsidies) and regulatory instruments (e.g., biofuel blending mandates). The Energy Policy Act of 2005 established a Renewable Fuel Standard (RFS) program, which increases the biofuel mandate to 36 billion gallons by 2022 from 9 billion gallons in 2008 (EIA, 2009). The Farm Bill of 2008 introduced a tax credit of $1.01 per gallon for cellulosic ethanol starting from 2009 (US DOE, 2008). The pre-existing tax credit for biodiesel of $1.00 was also extended (to the end of 2009).In Brazil, the government mandates 20-25% ethanol blends in all regular gasoline sales and the use of ethanol in government vehicles. It also promotes the sale of flexible-fuel vehicles, which represent 85% of all auto sales in Brazil (REN21, 2008). While ethanol production in Brazil was supported by price guarantees and subsidies, as well as public loans and state-guaranteed private bank loans, during the industry's development, it no longer receives any direct government subsidies. However, it is still supported by policies such as the ban on diesel- powered personal vehicles and one of the highest import tariffs on gasoline in the world. The EU Biofuels Directive of 2003 targets a 5.75% share of biofuels in transport energy by 2010, and 10% by 2020, prompting rapid growth in the production of biofuels. Despite its higher production costs, biodiesel is sold for $0.18 to $0.24 less per litre than conventional diesel in Germany due to the $0.59 tax exemption it enjoys there [6].

1.3 Biodiesel: Economical, Agricultural and Social Development

The major concern of biodiesel production is its economic feasibility. Economic advantages of biodiesel are: reduce country's reliance on crude oil imports and agriculture support by providing new labs or and market opportunities for domestic crops, foreign exchange saving. Investments in a plant increased employment and stable energy supply[7]. As biodiesel industry grow, significant economic opportunities can emerge for small-scale farmers and entrepreneurs as the production, transport, and processing of crop often takes place in rural areas. Rural communities can also derive income from the processing of biodiesel by-product such as pharmaceutical purposes, soap production, fertilization and cattle cakes etc.

Small-scale farmers and entrepreneurs have a role to play in leading the creation of biodiesel market, particularly in rural areas, and providing access to modern energy for local populations that were previously underserved. Biodiesel such as edible and non­edible oils and biodiesel can contribute to small-scale power production in rural areas and be competitive if displacing more expensive petroleum diesel. Ensuring that the economic and social benefits of biodiesel reach small-scale producers, however, will require ongoing efforts to reduce costs also require government support such as incentives for small-scale producers, seed distribution programs, minimum price warranties, an organization of farmers and cooperatives, information exchange and awareness raising, technical assistance and training etc.

1.4 All RTC buses to run on Biodiesel

The transport department has decided to run all State Road Transport Corporation (RTCs) buses on biodiesel. The first batch of 10 buses running on biodiesel was started. The Union Ministry of Petroleum and Natural Gas had issued a gazette notification allowing transporters to run buses(Figure 1.1) on biodiesel from 20 percent blend to 100 percent. The KSRTC has become the first transport company to run buses on biodiesel after the Centre's Order. The operational cost of buses would reduce drastically because of biodiesel costs lesser than regular diesel. The department would save about Rs. 50 crore annually by operating buses on biodiesel, besides it being environmentally friendly.

The step has been taken to cut down mounting fuel expenditure and conserve the environment. Presently, APSRTC consumes 50 crore litres of high-speed diesel per annum and replacing 10 percent of it with biodiesel would save around Rs 30 crore per annum. The State Road Transport Corporation (Telangana and Andhra Pradesh) spent Rs 2,367 crore on high-speed diesel alone during the FY 2013-14 and increasing prices of high-speed diesel have become a heavy burden. The APSRTC had used biodiesel in 19 depots on an experimental basis from 2008 to 2010, but biodiesel manufacturers were not ready to supply it to the APSRTC at economically viable prices due to high prices of raw material and escalation in production costs. However, as the gap between the prices of biodiesel and high-speed oil widened due to the steep increase in the cost high-speed diesel in recent months, biodiesel manufacturers are coming forward to supply it at Rs 6 to Rs 7 lesser per litre than the price of high-speed diesel. Fuel blended with 10 percent biodiesel would reduce pollutants like carbon monoxide, particulate matter and unburnt hydrocarbons to a considerable extent.

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Figure 1.1 Biodiesel bus

Environment Cleaner

In view of environmental considerations, biodiesel is considered “carbon neutral” because all the carbon dioxide released during consumption had been sequestered from the atmosphere for the growth of edible and non-edible oil crops or plants. Biodiesel is used as blends in different portions of petroleum diesel showed significant improvement in terms of greenhouses gases emission. It was observed that on combustion of biodiesel­petroleum diesel blends, the level of carbon monoxide (CO), carbon dioxide (C02), smoke, particulate matter (PM), sulphur dioxide (S02) and polyaromatic hydrocarbons (PAH) were reduced significantly; whereas the amount of oxide of nitrogen (NOx) was increased. Since biodiesel is oxygenated, the engine has complete combustion compare than petrodiesel.

Advantages of biodiesel

Biodiesel is domestically produced, it benefits Indian farmers, Indian businesses and national economy. Job creation, new markets for domestic agriculture product, and keeping our energy dollars domestic are just a few of the many economic benefits gained by using biodiesel instead of imported petroleum diesel. Biodiesel runs in any petroleum diesel engines. No engine modifications are necessary to use biodiesel. Biodiesel has a pleasant aroma in comparison to the toxic smell of petroleum diesel fuel. Engines running on biodiesel run normally and have similar fuel mileage to engines running on petroleum diesel fuel. Auto-ignition, fuel consumption, power output, and engine torque are relatively unaffected by biodiesel. Health problem as a result of emission exposure is also greatly reduced by the cleaner emission of biodiesel. According to the American Lung Association (ALA), biodiesel emissions are 90% less toxic than petroleum diesel and will reduce incidents of health hazards such as asthma, emphysema and lung cancer [8]. Biodiesel dramatically reduces harmful emissions that cause environment problem such as global warming, acid rain, smog. Biodiesel reduces C02 emission by over 78% compared to petroleum diesel. Even blended with petroleum diesel, biodiesel significantly reduces emission. Furthermore, the plants used to make biodiesel feedstock absorb more C02 as they grow than the biodiesel produces when it is burned. Biodiesel has excellent lubricity and can be added into petro-diesel to increase its lubricity.

1.5 Source of biodiesel

In recent years, the several developing countries have gained positive experience with the decentralized and small-scale production and use of oilseed crops and plants. It has been shown by a number of project and organizations. The production and use of biodiesel from local feedstock can make a positive contribution to improving access to sustainable and affordable energy. Cultivation, harvesting and plantation of fuel crops can enhance agricultural productivity and local economic development directly as well as indirectly through crop by-products. In addition, some biofuel emits much less pollutant than petroleum fuels and could significantly reduce negative impacts on public health. Biodiesel production and use can bring about positive gender effect since these are often women and children at the village and household levels who carry the load of agricultural production and fuel collection.

India depends on import of crude oil to satisfy energy demands. As the population and economy continue to grow, the demand will continue to increase. Concurrently, the pressure to reduce the environmental impact and mitigate climate change mounts. There is a possibility, that domestic production of biodiesel will replace some of the petroleum diesel use to reduce dependence on imported petroleum diesel and address environment issue planning commission 2003. Biodiesel has become a matter of global importance because of the need for an alternative energy at a cheaper price and with less pollution.

Table 1.1

Production of Biodiesel from edible, non-edible oil and animals fats in different Countries

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Nowadays, due to limited resources of petroleum fuels, rising crude oil prices and increasing concerns for the environment, there has been the focus on edible, non-edible oils, used cooking oil and animals fats as an alternative to petroleum fuel [8,9]. Biodiesel production from various edible, non-edible oil and animal fats in different countries is given in Table 1.1 [10]. In the Indian context, the bulk of the efforts have been directed toward obtaining biodiesel by chemical transesterification of Jatropha curses oil [11], and many other starting materials. However, it is felt that alternative starting oils also need to be studied [12]. An alternative approach would be one which focuses on multipurpose short duration annual crops that can either simultaneously yield fuel alone with food/Fodder or can be cultivated in rotation with food crops so that even small private farmer can be benefited. Some crops that already commercially known and can be scaled up production for bio-energy.

1.6 Selection of Potential Feedstock

Biodiesel also is known as fatty acid methyl ester (FAME) is derived from renewable lipid feedstock. Atabani et al., 2012; Salvi and Panwar, 2012 [13,14] reported that more than 350 oil-bearing plants have been identified as potential sources for biodiesel production. Different types of fats and oils have been used in different countries as the raw material for biodiesel production, depending on availability, regional climate, geographical location and local soil conditions [15, 16]. These feedstocks are divided into three categories i.e. edible oil, non-edible oil, animal fats. Non-edible vegetable oils which are known as the second generation feedstocks can be considered as promising substitutions for traditional edible food crops for the production of biodiesel. The use of non-edible plant oils is very significant because of the tremendous demand for edible oils as a food source. Moreover, edible oils feedstock costs are far expensive to be used as fuel. Therefore, production of biodiesel from non-edible oils is an effective way to overcome all the associated problems with edible oils. However, the potential of converting non-edible oil into biodiesel must be well examined. The selected non-edible oils are Used Cooking Oil, Cottonseed oil, Jatropha seeds, Neem oil. According to these feedstocks should fulfil two main requirements; low production cost and large production scale. Table 1.2 shows the general breakdown cost for the production of biodiesel [17-22].

Table 1.2

General breakdown cost of biodiesel production [17-22]

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1.6.1 Major tree borne oilseeds

1.6.1.1 Cottonseed oil

Cotton is one of the most important commercial crops in India and is the single largest natural source of fibre. It plays a dominant role in its agrarian and industrial economy as the backbone of the textile industry, which consumes 70% of the country's total fibre produced. Thus, the cotton production plays a vital role in the Indian economy, providing employment for more than one million farmers and employees in the domestic textile industry.

Cottonseed contains hull and kernel. The hull produces fibre and litres. The kernel contains oil, protein, carbohydrate and other constituents such as vitamins, minerals, lecithin, sterols etc. Cottonseed oil is extracted from cottonseed kernel. Cottonseed oil also termed as "Heart Oil" is among the most unsaturated edible oils. It need not be as fully hydrogenated for many cooking purposes as is required in case of some of the more polyunsaturated oils. The cottonseed contains fatty acids, both saturated (C14:0, C16:0, etc.) and unsaturated (C18:1, C18:2, C18:3)· Cottonseed oil has a ratio of 2:1 of polyunsaturated to saturated fatty acids and generally consists of 65-70% unsaturated fatty acids including 18-24% monounsaturated (oleic) and 42-52% polyunsaturated (linoleic) and 26-35% saturated (palmitic and stearic) as shown in Table 1.4 and properties of crude cottonseed oil as shown in Table 1.3.

Figures deleted due to copyright issues

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Table 1.3

Properties of crude cottonseed oil

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Table 1.4

Fatty acid composition of cotton seed oil

1.6.1.2 Jatropha oil

Jatropha (Jatropha Curcas) belonging to the Euphorbiaceae family is a genus comprising 70 species growing in tropical and subtropical countries. Recently Jatropha is being considered as one of the most promising potential oil sources to produce biodiesel in Asia, Europe and Africa. Jatropha can grow under a wide variety of climatic conditions like severe heat, low rainfall, high rainfall and frost. Jatropha is grown in marginal and wastelands with no possibility of land use competing with food production. Jatropha oil content varies depending on the types of species, climatic conditions and mainly on the altitude where it is grown. Various parts of the plant have medicinal values. Apart from supplying oils for diesel replacement, the growing of the tree itself effectively reduces CO2 concentrations in the atmosphere. The flowers only develop terminally (at the end of a stem), so a good ramification (plants presenting many branches) produces the greatest amount of fruits. The plants are self-compatible In developing countries like India it has been identified as the major source of biodiesel. Jatropha, the wonder plant produces seeds with an oil content of around 34%. The Jatropha oil can be used directly as liquid fuel in older diesel engines, in generators and pumps running at a constant speed or in newer engines with small modifications in the fuel system. The properties and fatty acid composition of Jatropha oil have been reported in Table 1.5 & 1.6 [24]. The seed contains toxins, such as phorbol esters, curcin, trypsin inhibitors, lectin and phytates, which render the seeds, oil and seed cake non-edible if not detoxified.

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Jatropha Curcas seeds and oil

Table 1.5

Properties of crude Jatropha oil

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Table 1.6

The fatty acid composition of crude Jatropha oil

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1.6.1.3 Neem oil

Neem (Melia Azadirachta) is of Meliaceae family. The other names of neem are Margosa, Veppam, Vepun, Nimba and Vepa (Telugu) etc. It is one of the two species in the genus Azadirachta, and is native to India and Burma, growing in tropical and semi­tropical regions. Neem is a fast-growing tree and can reach up to a height of 15 - 20 merrily to 35 - 40 m. It bears an ovoid fruit, 2cm by 1cm and each seed contains one kernel. The seed kernels, which weigh 0.2g, constitute some 50-60% of the seed weight and 25% of the fruit. The fat content of the kernels ranges from 33-45%. The fruit yield per tree is 37-55 kg. Neem oil can be used as Soaps, medicinal and insecticide. Neem oil is usually opaque and bitter but it has recently been shown that it can be processed into the non bitter edible oil with 50% oleic acid and 15% linoleum acid. The bitter cake after extraction of oil has no value for animal feeds although it has been reported that after solvent extraction with alcohol and hexane a meal suitable for animals is produced. Neem seeds are usually crushed prior to extraction in ghanis. Whole dried fruits may be directly passed to expeliere. Good quality kernels (50% oil) yield 40% oil in ghanis. In expeliere whole dried fruits, depulped seeds and kernels, yield 4-6%, 12-16% and 30-40% oil respectively. The cakes, which contain 7-12% oil are sold for solvent extraction. The physicochemical analysis and fatty acid composition of neem oil has been reported in Table 1.7 & 1.8

Figures deleted due to copyright issues

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Table 1.7

Properties of Neem Oil (O. O. Awolu et al., 2013)

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Table 1.8

The fatty Acid composition of Neem Oil

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1.6.1.4 Used Cooking Oil (UCO)

The feedstock coming from waste vegetable oils or commonly known as waste cooking oils (Used cooking oils) is one of the alternative sources of other higher grade or refined oils. Used cooking oil is easy to collect from other industries such as domestic usage and restaurant and also cheaper than other oils (refine oils). Hence, by using these oils as the raw material, we can reduce the cost of biodiesel production [25]. The advantages of using waste cooking oils to produce biodiesel are the low cost and prevention of environmental pollution. These oils, need to be a treat before disposing of the environment to prevent pollution. Due to the high cost of disposal, many individuals dispose waste cooking oils directly to the environment, especially in rural area. Encinar et ak, 2006[26] concluded that use of waste cooking oils is an effective way to reduce the cost of biodiesel production. UCO was found to be 2.5 - 3.5 times cheaper than virgin vegetable oils, depending on the sources and availability[27]. The amount of UCO generated each year in every country is quite massive, depending on the use of vegetable oil. The physicochemical analysis and fatty acid composition of UCO (palm oil) has been reported in Table 1.9 & 1.10

The properties of used cooking oil depend highly on the origin and history of the oil. The origin of used cooking oil determines its fatty acid compositions. The history or duration that the oil exposed to water, heat, food, micro-organisms and oxygen during cooking determines its physical and chemical properties such as viscosity, water content, free fatty acid content, and the presence of polymerized and oxidized compounds.

Figures deleted due to copyright issues

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Table 1.9

Properties of UCO (Palm oil)

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Table 1.10

The fatty acid composition of crude palm oil

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1.7 Selection of Alcohol

One of the renewable energy that has been receiving a lot of attention is biodiesel due to its similarity with conventional diesel in terms of chemical structure and energy content. Biodiesel, or also known as fatty acid alkyl esters is derived from triglycerides via transesterification reaction with alcohols such as methanol and ethanol. In the reaction performance is feasible to reach higher conversions with methanol, ethanol using the process is more complex, expensive, requires a higher consumption of energy and time. It requires less reaction time when using methanol rather than ethanol, either in acid or alkaline catalysis, reaching high yields. With the above, the methanol is selected to be used in the biodiesel production due to its lower cost, better performance and less time and energy during the reaction.

1.8 Selection of Catalyst

There are three common kinds of catalysts in the ester reaction: lipase catalysts, acid catalysts, and alkali catalysts. Each catalyst has its own advantages and disadvantages in the whole reaction process. As the catalyst, an enzyme is restricted to rigorous reaction condition and activity lose of lipase etc, it can't be used on the large commercial production until now.

1.8.1 Enzyme (Biocatalyst) catalyzed transesterification

Enzymatic transesterification has drawn researcher’s attention due to the downstream processing problem posed by chemical transesterification(Figure 1.2). A huge amount of wastewater generation and difficulty in glycerol recovery are some of the problems that eventually increase the overall production cost of biodiesel and is not environmentally benign. In contrast, enzyme catalysis occurs without the generation of by-products, easy recovery product, mild reaction condition, insensitive to high FFA oil and catalyst can be reuse [28]. Thus, enzyme-catalyzed biodiesel production has proven to have high potential to be an eco-friendly process and a promising alternative to the chemical process. However, enzyme-catalyzed biodiesel production has some limitations especially when implemented in industrial scale because of the high cost of enzyme, slow reaction rate and enzyme deactivation

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Figure 1.2 Enzymatic Biodiesel Production by Transesterification with Methyl Acetate

1.8.2 Acid-catalyzed esterification

Transesterification reactions can be catalyzed by both homogeneous and heterogeneous catalysts. The homogeneous catalysts include both alkalis and acids. Alkaline catalysts most commonly used are sodium and potassium hydroxides and methoxides; while the preferred acid catalysts include: sulfuric acid; hydrochloric acid. Acid-catalyzed esterification can be used to prepare esters from oil having a high free fatty acid content, The process has not gained as much attention as the base-catalyzed transesterification because of the slower reaction rate and the very high methanol to oil molar ratio requirements. The two-step biodiesel process addressed this issue by using an acid catalyst followed by a normal base-catalyzed transesterification. The first step involved the esterification reaction between the methanol and FFA to produce the corresponding fatty acid methyl ester(FAME) using H2SO4 as a catalyst. The soap formation can be avoided by using an acid catalyst. Liquid acid catalysts such as sulfuric acid are less sensitive to FFAs and can simultaneously conduct esterification and transesterification.

1.8.3 Alkali-catalyzed transesterification

Homogeneous alkaline catalysts are more preferable and commonly used since transesterification reaction using its acid counterpart has a slower rate (Figure 1.3) [28]. The most common basic catalysts are potassium hydroxide (KOH), potassium methoxide (KOCH3), sodium hydroxide (NaOH), and sodium methoxide (NaOCH3). These catalysts are commonly used because of several advantages such as able to catalyze the reaction at low reaction temperature and atmospheric pressure, high conversion in a shorter time, and economically available. Sodium methoxide (NaOCH3) and potassium methoxide (KOCH3) are the better catalyst than sodium hydroxide (NaOH) and potassium hydroxide (KOH) due to the ability to dissociate into CH3O' and Na+ and CH30and K+ respectively when comparing on biodiesel yield. Alkaline catalyst is more commonly used in commercial biodiesel production because it does not form water during transesterification reaction [15]. Potassium based catalysts (KOH and KOCH3) shows a higher biodiesel yield than sodium based catalysts (NaOH and NaOCH3) for longer reaction duration like 120 minutes. For shorter reaction duration like 30 to 60 minutes, sodium-based catalysts (NaOH and NaOCH3) achieved the better biodiesel yield.

Overall reaction:

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Figure 1.3 Transesterification of Triglycerides with a base catalyst

1.9 Motivation of Research Work

The four important issues i.e. economic analysis of current and future sources of energy, selection of a reliable feedstock as a raw material, selection of a suitable process in biodiesel production depending on the source of the feedstock and selection of a suitable catalyst for the biodiesel production should be carefully considered to improve the performance of biodiesel synthesis. The main focus of this research work is to create a green and environmentally benign process for biodiesel production and to reduce the dependency on food supplement materials i.e. vegetable oils as the feedstocks. The study will focus on the usage of allow quality feedstock i.e. uco due to the following reasons: (i) to reduce the production cost of biodiesel, (ii) to avoid the competition between the food and fuel industry, (iii) to have a sustainable green environment by converting waste oil into a useful product i.e. biodiesel and (iv) to increase the awareness among the citizens on the importance of waste recycling. Furthermore, the usage of low-quality feedstocks i.e. non-edible oil, animal fats and used oil has gained more interest in recent years as the physicochemical properties of these feedstocks are found to be compatible with biodiesel production. Although the biodiesel esterification and transesterification reactions using acid and base catalysts are well known and practised on a commercial scale, there is still plenty of scope for improvement, especially on the development of suitable and sustainable catalysts for low-quality biodiesel feedstocks.

1.10 Objectives of the Research Work

- A comparative study of enzymatic(Lipase) and acid-alkaline transesterification of methyl esters of Used Cooking Oil (UCO), Cottonseed, Jatropha and Neem oil at optimized parameters
- Screening of methyl esters of UCO & Jatropha and its optimization using Response Surface Methodology (RSM) and analysis of variance(ANOVA), the significance of the different process parameters and their combined effects on the transesterification efficiency were established through a full factorial Central Composite Design (CCD).
- To develop the analytical technique for the determination of fatty acid methyl ester (FAME) using Gas Chromatography-Mass Spectroscopy (GC-MS). Elemental analysis was analyzed and functional groups of methyl ester were investigated using Fourier Transforms Infrared Spectroscopy (FTIR).
- To characterize the methyl ester via chemical and physical characteristic methods of the biodiesel according to ISO norms and are compared to that of petroleum diesel.
- To study the performance and emission characteristics of C.I engine fuelled with methyl ester.
- To evaluate the cost and benefit of the methyl ester.

1.11 Rationale and Significances

The rationale of this research is to identify the important variables and to propose a suitable approach in scaling up the production of biodiesel from UCO and Jatropha oil using batch transesterification process. With the important variables such as the ratio of methanol to oil, catalyst concentration, reaction temperature, and reaction time used, we can produce high quality of biodiesel which has a high yield and high purity of methyl ester content.

The high energy demand in the industrialized world as well as in the domestic sector had caused pollution problems due to the widespread use of fossil fuels make it increasingly necessary to develop the renewable energy sources of a smaller environmental impact than the fossil fuels such diesel fuels. The alternative fuel must be technically feasible, economically competitive, environmentally acceptable and readily available that is familiar to biodiesel properties. Biodiesel is a non-toxic and biodegradable fuel made from renewable plant oils and animal fats.

This work, therefore, seeks to produce test quantities of a methyl ester of uco and Jatropha oil via transesterification. This work further seeks to characterize the uco and Jatropha biodiesel produced as alternative diesel fuel through a test for viscosity, specific gravity acid value, free fatty acid, saponification value cloud point, pour point and flash point. The results are expected to contribute to baseline data needed for future replacement of petroleum diesel with renewable biodiesel. Specifically, these findings will find useful applications in the energy sector of the Indian economy.

REFERENCES

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[2] . A.s. Abdulkareem, A. Jimoh, J.o. Odigure, D. Patience and A.s. Afolabi, (2012). Production and Characterization of Biofuel from Non-Edible Oils: An Alternative Energy Sources to Petrol Diesel, energy conservation, 171-192.

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[4] . Ajay V. Kolhe, R.E.Shelke and S.S.Khandare, (2014). Performance and Combustion Characteristics of a DI Diesel Engine Fueled with Jatropha Methyl Esters and its Blends, Jordan journal mechanical and industrial engineering, 8(1), 7-12.

[5] . Ewa Klugmann-Radziemska, (2014). Environmental Impacts of Renewable Energy Technologies, Environmental science and technology, 69(21), 104-109.

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[7] .M0jtaba mansourpoor, Ahmad Shariati, (2012). Optimization of biodiesel production from sunflower oil using response surface methodology, chemical engineering and technology, 3(4), 1-5.

[8] . Elisa Marino, Massimo Caruso, Davide Campagna, and Riccardo Polosa(2015). Impact of air quality on lung health: myth or reality, therapeutic advances in chronic disease, 6(5), 286-295.

[9] . K.s. Mehra, M.p. Shah, s. Singh, (2014). Use of Non-Edible Vegetable Oils as Fuel for Diesel Engine: A Review, International Journal for Research in Applied Science and Engineering Technology (URASÉT), 2(8), 6-11.

10]. M.K. Mohanty and s. Mishra, (2013). Biodiesel Production from Different Non­edible oils containing High Free Fatty Acid, International Journal of Scientific & Engineering Research, 4(12), 155-159.

[11] . G. Francis, R. Edinger, K. Becker, (2005). A concept for simultaneous wasteland reclamation, fuel production, and socio-economic development in degraded areas in India: need, potential and perspectives of Jatropha plantation, National Resource Forum, 29(1), 12-24.

[12] . A. Srivastava and R. Prasad, (2000). Triglycerides-based diesel fuels, Renewable and Sustainable Energy Reviews, 4(2), 111-133.

[13] . A.E. Atabani, A.s. Silitonga, I.A. Badruddin, T.M.I. Mahlia, H.H. Masjuki, s. Mekhilef, (2012). A comprehensive review on biodiesel as an alternative energy resource and its characteristics, Renewable and Sustainable Energy Reviews, 16(4), 2070-2093.

[14] . B.L.Salvi and N.L. Panwar, (2012). Biodiesel resources and production technologies- A review, Renewable and Sustainable Energy Reviews, 16(6), 3680-3689.

[15] . Y.C.Sharma and B. Singh, (2008). Development of biodiesel from Karanja, a tree found in rural India, Fuel, 87(8-9), 1740-1742.

[16] . A. Murugesan, c. Umarani, T.R. Chinnusamy, M. Krishnan, R. Subramanian, N. Neduzchezhain, (2009). Production and analysis of bio-diesel from the non-edible oils-A review, Renewable and Sustainable Energy Reviews, 13(4),825-834.

[17] .B. Supple, R. Holward-Hildige, E.Gonzalez-Gomez, J. J. Leahy, (2002).The effect of steam treating waste cooking oil on the yield of methyl ester, Journal of the American Oil Chemists Society, 79(2), 175-178.

[18] .A.V. Tomasevic and s.s. Silver-Marinkovic, (2003). Methanolysis of used frying oil, Fuel Process Technology, 81(1), 1-6.

[19] . M. Canakci and J. Van Gerpen, (2001). Biodiesel production from oils and fats with high free fatty acids, Transactions of the ASAE, 44(6), 1429-1436.

[20] . A.s. Ramadhas, s. Jayaraj, c. Muraleedharan, (2005). Biodiesel production from high FFA rubber seed oil, Fuel, 84(4), 335-340.

[21] . S. Behzadi and M.M. Farid, (2007). Review: examining the use of different feedstock for the production of biodiesel, Asia Pacific Journal Chemical Engineering, 2(5), 480-486.

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[23] . M. G. Kulkami and A. K. Dalai, (2006).Waste Cooking Oils an Economical Source for Biodiesel: A Review, Industrial and engineering chemistry research, 45, 2901-2913.

[24] R. p. s. Katwal and P. L. Soni, (2003). Biofuels: an opportunity for socioeconomic development and a cleaner environment, Indian Forester, 129(8), 939-949.

[25] . M. Canakci and J. Van Gerpen, (2001). Biodiesel production from oils and fats with high free fatty acids, Transactions of the American Society of Advanced Engineering, 44, 1429-1436.

[26] . J.M. Encinar, J.F. Gonzalez, A. Rodríguez-Reinares, (2005). Biodiesel from used frying oil; Variables affecting the yields and characteristics of the biodiesel, Industrial & Engineering Chemistry Research, 44, 5491-5499.

[27] . M. Balat, (2011). Potential alternatives to edible oils for biodiesel production-A review of current work, Energy Conversion & Management, 52(2),1479-1492.

[28] .E. Lotero, Y. Liu, D. E. Lopez, K. Suwannakam, D. А. Втсе, J. G. Goodwin, (2005). Synthesis of Biodiesel via Acid Catalysis, Industrial and engineering chemistry research, 44(14), 5353-5363.

CHAPTER-2
LITERATURE REVIEW

This chapter deals with the review of the literature. It reviews the history, use, advantages and disadvantages of bio fuels and biodiesel in particular, world biodiesel production and the chemistry of biodiesel production. Biodiesel feedstocks (used cooking oil, cotton seed oil, Jatropha oil and neem oil) requirements and characteristics are also discussed in this chapter. The chapter also reviews literature on the significance of the different process parameters and their combined effects on the transesterification efficiency were established through a full factorial central composite design(CCD). The properties, quality control of biodiesel, further the performance, emission characteristics and cost analysis of biodiesel were also emphasized in the literature review.

2.1 Transesterification process:

Sanette Marx, et al.,[l] reviewed the importance of Waste oils as feedstock for the production of fuels and chemicals. However, the high level of impurities in waste oils limits their use in transesterification reactions where methanol is used as acyl acceptor. A second consequence of increased biodiesel production is the oversupply of glycerol into the market that has caused a sharp decrease in glycerol prices. Novel production routes are thus necessary to limit glycerol formation while also allowing the use of crude or contaminated oil as feedstock. The aim of this work is to review the state of glycerol-free biodiesel synthesis routes with emphasis on routes using methyl acetate or dimethyl carbonate (DMC) as acyl acceptors. Dimethyl carbonate is favoured as acyl acceptor when using biocatalysts for synthesis, while methyl acetate is favoured as acyl acceptor in supercritical-assisted transesterification. Both dimethyl carbonate and methyl acetate as acyl acceptors are able to tolerate impurities such as free fatty acids, but methyl acetates has a higher tolerance for water in the feedstock than dimethyl carbonate. The performance of both acyl acceptors in the presence of used motor oils and industrial greases need to be investigated to assess the suitability for industrial application.

Fabiano,et al.,[2] stated that biodiesel is an alternative nonpetroleum based fuel, consisting of alkyl esters obtained either by esterification of free fatty acids with low molecular weight alcohols, or by transesterification of triglycerides. The realization of a biodiesel unit can pose several safety issues and inherent safety application opportunities as the production involves the transport, use and storage of hazardous materials, either flammable or toxic. In the experimental phase, we studied, at laboratory scale, different alkali catalysts and the relevant reaction parameters, considering inherent safety opportunities. An accurate kinetic model of the transesterification process was developed and validated, allowing to provide possible minimization and simplification plant options.

Feng Guo et al.,[3] conducted experiments on stability tests and stated that Solid calcined sodium silicate (CSS) was successfully used to produce biodiesel from vegetable oil, but its transesterification mechanism is still not well-understood. In this work, stability tests confirmed that some active basic species were leached into methanol from CSS. FT-IR spectra and density functional theory were employed to deduce the mechanistic route of transesterification reactions catalyzed with css. It was confirmed that alkaline active species were formed from the ion-exchange between css and CH3OH. Deactivated css can be reused by regenerating the active sites using a simple method found by them.

2.2 Enzymatic catalyzed transesterification

Shinji Hama, et ak,[4] reviewed the increased global demand for biofuels has prompted the search for alternatives to edible oils for biodiesel production. Given the abundance and cost, waste and nonedible oils have been investigated as potential feedstocks. A recent research interest is the conversion of such feedstocks into biodiesel via enzymatic processes, which have considerable advantages over conventional alkali-catalyzed processes. To expand the viability of enzymatic biodiesel production, considerable effort has been directed toward process development in terms of biodiesel productivity, application to wide ranges of contents of water and fatty acids, adding value to glycerol byproducts, and bioreactor design. A cost evaluation suggested that, with the current enzyme prices, the cost of catalysts alone is not competitive against that of alkalis.

However, it can also be expected that further process optimization will lead to a reduced cost in enzyme preparation as well as in downstream processes.

Akhil Bajaj, et al.,[5] stated that recently, with the global shortage of fossil fuels, excessive increase in the price of crude oil and increased environmental concerns have resulted in the rapid growth in biodiesel production. The central reaction in the biodiesel production is the transesterification reaction which could be catalyzed either chemically or enzymatically. Enzymatic transesterification has certain advantages over the chemical catalysis of transesterification, as it is less energy intensive, allows easy recovery of glycerol and the transesterification of glycerides with high free fatty acid contents. Limitations of the enzyme catalyzed reactions include high cost of enzyme, low yield, high reaction time and the amount of water and organic solvents in the reaction mixture. Researchers have been trying to overcome these limitations in the enzyme catalyzed transesterification reaction. This paper is meant to review the latest development in the field of lipase catalyzed transesterification of biologically derived oil to produce biodiesel.

Pattarawadee Kimtun et al., [6] carried out experiments to extract and characterize lipase from oil palm after 0-240 h of harvesting. In addition, the application of lipase as catalyst for biodiesel production was also evaluated. Lipase was extracted and purified by Tris­base buffer (pH 8.0) and the aqueous two phase system (ATPS), respectively. The highest protein at 1.96 mg/gat was obtained from oil palm fruit at 0 h of harvesting. However, the highest lipase activity at 0.98 Units (1.38 Unit/mg protein) was achieved from palm oil after 120 h of harvesting. Afterwards, lipase was collected and purified by ATPS using PEG 1000 under the variation of salts. After purification, lipase activity was increased significantly to 4.76 Unit/mg protein using PEG and NaH2P04. Therefore, purified lipase was utilized as catalyst for biodiesel production using the transesterification method and the partial properties of biodiesel from lipase were also determined. The biodiesel from lipase had an acid value and free fatty acid content at 0.45 mg/g KOH and 0.21%, respectively. The properties of biodiesel were also compared with commercial biodiesel. Interestingly, the acid value and free fatty acid content of biodiesel from lipase were not significantly different from commercial biodiesel and it also passed Thailand’s fuel standards.

Zeynab Amini et al., [7] demonstrated in the present work biodiesel production from Ocimum basilicum (sweet basil) seed oil by lipase-catalyzed transesterification. The increasing global demand for fuel, limited fossil fuel resources, and increasing concern about the upturn in gaseous C02 emissions are the key drivers of research and development into sources of renewable liquid transport fuels, such as biodiesel. Sweet basil seeds contain 22% oil on a dry weight basis. Artificial neural network with genetic algorithm modelling was used to optimize reaction. Temperature, catalyst concentration, time, and methanol to oil molar ratio were the input factors in the optimization study, while fatty acid methyl ester (FAME) yield was the key model output. FAME composition was determined by gas chromatography mass spectrometry. The optimized transesterification process resulted in a 94.58% FAME yield after reaction at 47 c for 68 h in the presence of 6% w/w catalyst and a methanol to oil ratio of 10:1. The viscosity, density, calorific value, pour point, and cloud point of the biodiesel derived from sweet basil seed oil conformed to the EN 14214 and ASTM D6751 standard specifications. The antioxidant stability of the biodiesel did not meet these specifications but could be improved via the addition of antioxidant.

2.3 Alkali catalyzed transesterification

Abdelrahman et ak,[8] Investigated the production of biodiesel from the fat that extracted from beef tallow waste using alkali catalyzed transesterification and also employed Two methods of transesterification including single-step transesterification (SSTE) and two-step transesterification (TSTE). In both methods, KOH or NaOH with methanol was used. The reactions were performed at two temperatures (32 and 60 °C) for a fixed duration that is 1 h. The fuel properties of the produced biodiesel were assessed. The results indicated that, both methods of the transesterification were successful to enhance the fuel properties of the tallow as compared to the direct use of it as a fuel. Besides, the values of the assessed properties met the specified limits according to the ASTM standards. Thin layer chromatography was used for monitoring the transesterification reaction of the optimal biodiesel sample using a silica gel plate.

Furthermore, blending of the optimum biodiesel sample with petro-diesel was made using different volume percentages (10, 20 and 30%). The results disclosed that biodiesel had a slight influences on the assessed properties of petro-diesel.

Madhu Agarwal et ah, [9] stated that Increased industrialization and motorization are the major cause of environmental pollution and diminishing petroleum reserves. Biodiesel being renewable and environment friendly is one of the alternate sustainable energy sources having similar fuel properties as that of petroleum diesel. The objective of this study is to produce biodiesel from cheap raw material (waste cooking oil) and to get optimum reaction conditions for both homogeneous and heterogeneous catalytic transesterification. A comparison is also made to make the transesterification process techno-economically feasible. Potassium hydroxide (KOH) was selected as a homogeneous catalyst and KOH loaded on alumina as a heterogeneous catalyst. A yield of 96.8% fatty acid methyl ester (FAME) was obtained with heterogeneous catalyst at the optimum conditions of reaction temperature 70 8C, reaction time 2 h, catalyst concentration 5%, catalyst loading 15 wt%, and methanol to oil molar ratio 9:1, whereas 98.2% yield was obtained with homogeneous KOH catalyst at the optimum reaction conditions of reaction temperature 70 8C, reaction time 1 h, catalyst concentration 1%, and methanol to oil molar ratio 6:1. The fuel properties were also measured for biodiesel to observe its competitiveness with conventional diesel fuel. Reusability test of KOH loaded on alumina catalyst gave reasonable yield up to 3 cycles.

Le Tu Thanh et al.,[10] stated that more than 10 million tons of biodiesel fuel (BDF) have been produced in the world from the transesterification of vegetable oil with methanol by using acid catalysts (sulfuric acid, H2S04), alkaline catalysts (sodium hydroxide, NaOH or potassium hydroxide, KOH), solid catalysts and enzymes. Unfortunately, the price of BDF is still more expensive than that of petro diesel fuel due to the lack of a suitable raw material oil. Here, we review the best selection of BDF production systems including raw materials, catalysts and production technologies. In addition, glycerol formed as a by­product needs to be converted to useful chemicals to reduce the amount of glycerol waste. With this in mind, we have also reviewed some recent studies on the utilization of glycerol.

[...]

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Title
Assessment of the potential of methyl ester production from non-edible oils
College
Andhra University  (College of engineering)
Grade
A
Author
Year
2017
Pages
236
Catalog Number
V432128
ISBN (eBook)
9783668795754
ISBN (Book)
9783668795761
Language
English
Tags
assessment
Quote paper
Venu Gopal (Author), 2017, Assessment of the potential of methyl ester production from non-edible oils, Munich, GRIN Verlag, https://www.grin.com/document/432128

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