OPTIMIZING BIODIESEL PRODUCTION FROM RUBBER SEED OIL USING

CONVENTIONAL METHOD

SARVIN RAM A/L SERIRAMULU

This report is submitted in partial fulfilment

of the requirements for the award of the degree in

Bachelor of Mechanical Engineering (Thermal-fluid)

Faculty of Mechanical Engineering

University Teknikal Malaysia Melaka

JULY 2015

i

SUPERVISOR DECLARATION

“I hereby declare that I have read this thesis and in my opinion this report is sufficient in

terms of scope and quality for the award of the degree of

Bachelor of Mechanical Engineering (Thermal-Fluid)”

Signature : ………………………….

Supervisor : Pn. Nur Fathiah Binti Mohd Nor

Date : 1st JULY 2015

ii

STUDENT’S DECLARATION

“I hereby declare that the work in this report is my own except for summaries and

quotations which have been duly acknowledged.”

Signature : ………………………..

Author : Sarvin Ram a/l Seriramulu

Date : 1st JULY 2015

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Dedicated to my beloved Father and Mother

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ACKNOWLEDGEMENT

I would like to take this opportunity would like to express my deepest

appreciation and thanks to all who have provided their full support towards my Final

Year Project. This acknowledgement is not just a position of words but also as an

account of indictment. They have been a guiding light and source of inspiration towards

the completion of this report. I am very grateful to my Project Supervisor, Pn. Nur

Fathiah Binti Mohd Nor for her kind and timely help offered to me in execution of this

report. Besides that, I would like to thank my family, and all my friends who with their

valuable suggestions and support, directly or indirectly helped me in the completion of

this report.

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ABSTRACT

The rapid increase in the use of the world’s crude oil reserve and diminishing of

the natural source has accelerated the hunt for renewable energy. Biodiesel has proven to

be able to provide energy as per the requirement of various sectors and will required in a

large scale. This study focuses on the optimization of biodiesel production using rubber

seed oil (RSO) via transesterification process which is proven to be the easiest and most

productive method for biodiesel production in large scale with the aid of cockle as

catalyst. The optimization of analytical procedures has been carried out by using Minitab

software where the chosen multivariate statistic technique is Response Surface

Methodology (RSM) in order to determine the optimum parameters values so that

optimum yield can be achieved. The parameters involved are methanol to oil ratio,

catalyst weight percentage, and reaction time. From the analysis done using Minitab

software, the result obtained for optimum yield is 99.63 % by using parameter values of

18:1 methanol to oil ratio, 5 % catalyst weight percentage, and 2 hours reaction time.

This study proves that production of biodiesel in a large scale is achievable and a step

into a greener future where power generation solely depends on renewable sources.

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ABSTRAK

Peningkatan pesat dalam penggunaan minyak mentah dunia yang diperolehi daripada

sumber semula jadi yang semakin berkurangan telah mempercepatkan pemburuan untuk

tenaga boleh diperbaharui. Biodiesel terbukti dapat membekalkan tenaga kepada

pelbagai sektor dan akan diperlukan dalam skala yang besar. Kajian ini memberi

tumpuan kepada pengoptimuman pengeluaran biodiesel menggunakan minyak daripada

biji getah melalui proses transesterifikasi yang terbukti menjadi kaedah yang paling

mudah dan paling produktif untuk pengeluaran biodiesel dalam skala besar dengan

bantuan kulit kerang sebagai pemangkin. Analisis prosedur pengoptimuman telah

dijalankan dengan menggunakan perisian Minitab di mana teknik statistik multivariat

yang dipilih adalah kaedah ‘Response Surface Methodology’ (RSM) untuk menentukan

nilai parameter optimum yang mampu menghasilkan isi padu biodiesel yang tinggi.

Parameter-parameter yang terlibat adalah nisbah molar metanol terhadap minyak,

peratusan berat pemangkin, dan masa tindak balas. Dari analisis yang dilakukan dengan

menggunakan perisian Minitab, keputusan yang diperolehi untuk penghasilan biodiesel

yang optimum adalah kadar penukaran sebanyak 99.63% dengan menggunakan nilai-

nilai parameter, nisbah metanol terhadap minyak sebanyak 18:1, 5% berat pemangkin,

dan masa tindak balas selama 2 jam. Kajian ini membuktikan bahawa pengeluaran

biodiesel dalam skala yang besar boleh dicapai dan langkah ke masa depan yang lebih

hijau di mana penjanaan kuasa hanya bergantung kepada sumber-sumber yang boleh

diperbaharui.

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TABLE OF CONTENT

CHAPTER CONTENT PAGE

SUPERVISOR DECLARATION i

STUDENT DECLARATION ii

DEDICATION iii

ACKNOWLEDGEMENT iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENTS vii

LIST OF TABLES x

LIST OF FIGURES xi

LIST OF SYMBOLS xiii

LIST OF ABBREVIATIONS xiv

CHAPTER 1 INTRODUCTION 1

1.1 Project Background 1

1.2 Problem Statement 3

1.3 Project Objective 4

1.4 Project Scope 4

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CHAPTER 2 LITERATURE REVIEW 5

2.1 Rubber Seed Oil 5

2.2 Basic Chemical Reactions 6

2.3 Biodiesel Production Processes 7

2.3.1 Raw Material Properties 7

2.3.1.1 Gas Chromatography (GC) 8

2.3.1.2 Acid Value and FFA 9

2.3.1.3 Saponification Number 9

2.3.1.4 Iodine Value (IV) 10

2.3.1.5 Kinematic Viscosity 10

2.3.2 Catalyst and Alcohol 11

2.3.3 Esterification Process 13

2.3.4 Mixing and Neutralization 13

2.3.5 Transesterification and Separation 14

2.4 Conventional Method 15

2.5 Properties of Biodiesel 16

2.6 Optimization of Biodiesel 17

2.6.1 Reaction Time 21

2.6.2 Methanol to Oil Ratio 21

2.6.3 Catalyst Weight Percentage 22

CHAPTER 3 METHODOLOGY 23

3.1 Introduction 23

3.2 Acid Value Experiment 23

3.3 Saponification Number Experiment 25

3.4 Iodine Value (IV) Experiment 25

3.5 Density Measurement 26

3.6 Kinematic Viscosity Experiment 27

3.7 Acid Esterification Process 28

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3.8 Transesterification Process 29

3.9 Flash Point Test 30

3.10 Minitab Software Analysis Process 32

3.11 Biodiesel Production and Optimization Flow

Chart

39

CHAPTER 4 RESULTS AND DISCUSSION 40

4.1 Properties of Rubber Seed Oil 40

4.1.1 Gas Chromatography for Rubber Seed

Oil

42

4.1.2 Average Molecular Weight of RSO 43

4.2 Acid Esterification and Transesterification of

Rubberseed Oil

44

4.3 Properties of Biodiesel from Rubber Seed Oil 45

4.4 Manipulated Parameters and Yield for Biodiesel 46

4.5 Analysis of Minitab Software 47

4.6 Main Effect and Interaction Plot for Yield 50

4.7 Relationship of Parameters and Response 53

4.7.1 Yield vs. Methanol, Catalyst 53

4.7.2 Yield vs. Time, Methanol 55

4.7.3 Yield vs. Time, Catalyst 56

4.8 Response Optimization for Yield 57

CHAPTER 5 CONCLUSION & RECOMMENDATIONS 59

REFERENCE 61

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LIST OF TABLES

NO. TITLE PAGE

2.1 Comparison between the types of catalyst 12

2.2 ASTM D6751 biodiesel standard 17

2.3 Structural Design of CCD for 3 factors 20

3.1 Density value of distilled water based on temperature 27

4.1 Properties of Rubber Seed Oil 40

4.2 Gas Chromatography Result for Rubber Seed Oil 42

4.3 Fatty Acid Molecular Weight 43

4.4 Comparison of Biodiesel Properties with ASTM Standard 45

4.5 Parameter Manipulation during Transesterification Process 46

4.6 Comparison between Experimental Yield and Theoretical

Yield

50

xi

LIST OF FIGURES

NO. TITLE PAGE

2.1 Schematic view of the chemical reaction during

transesterification

7

2.2 Process Flow Chart of a GC Machine 9

2.3 The example points of a Central Composite design with

three factors

18

3.1 Cool titration process 24

3.2 Brookfield Digital Viscometer model DV-II+ 28

3.3 Constant temperature electric heater with magnetic stirrer 30

3.4 Main components of flash point tester 31

3.5 Interface of Minitab Software for Create Response Surface

Design

32

3.6 Parameter Manipulation for Structural Design of CCD 33

3.7 Interface of Minitab Software for Analyze Response Surface

Design

34

3.8 Interface of Minitab Software for Yield Prediction 35

3.9 Interface of Minitab Software for Factorial Plots 36

3.10 Interface of Minitab Software for Graph Generation 37

3.11 Interface of Minitab Software for Response Optimizer 38

3.12 Flow Chart for Biodiesel Production 39

4.1 Separation from acid esterification process 44

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4.2 Separation from transesterification process 44

4.3 Model Summary and Coded Coefficients 48

4.4 Graph for Normal Probability Plot 48

4.5 Regression Equation for Response Surface Model 49

4.6 Graph of Main Effects Plot for Yield 51

4.7 Graph of Interaction Plot for Yield 52

4.8 Surface Plot Graph of Yield vs. Catalyst, Methanol 53

4.9 Contour Plot Graph of Yield vs. Catalyst, Methanol 54

4.10 Surface Plot Graph of Yield vs. Time, Methanol 55

4.11 Contour Plot Graph of Yield vs. Time, Methanol 55

4.12 Surface Plot Graph of Yield vs. Time, Catalyst 56

4.13 Contour Plot Graph of Yield vs. Time, Catalyst 57

4.14 Response Optimization for Yield 58

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LIST OF SYMBOLS

OC = degree Celsius

g = grams

ml = milliliter

N = Normality

cm = centimeter

ρ = density

mg = milligram

g/mol = gram per mol

m2/s = meter squared per second

mm2/s = millimeter squared per second

mgKOH/g = milligram KOH per gram

kg/L = kilogram per liter

g Iodine/100g = gram Iodine per 100 gram

% = percent

mm/s2 = millimeter per second squared

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LIST OF ABBREVIATIONS

FAME = Fatty Acid Methyl Esters

TAG = Triacylglycerol

RSO = Rubber Seed Oil

CaO = Calcium Oxide

FFAs = Free Fatty Acids

wt.% = Weight Percentage

RSM = Response Surface Methodology

AV = Acid Value

GC = Gas Chromatography

N2 = Nitrogen

H2 = Hydrogen

He = Helium

KOH = Potassium Hydroxide

IV = Iodine Value

I2 = Iodine

cST = Centistokes

RCOOR’ = Ester

H2SO4 = Sulphuric Acid

ASTM = American Society and Testing and Material

DMAIC = Define, Measure, Analyze, Improve, and Control

DOE = Design of Application

CCD = Central Composite Design

ATM = Atmospheric

xv

R-sq = Regression squared

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CHAPTER 1

INTRODUCTION

1.1 PROJECT BACKGROUND

The rapid increase in the use of the world’s crude oil reserve and diminishing of

the natural source has accelerated the hunt for renewable energy. Renewable energy is

energy source that use natural resources which have the potential to produce energy with

minimum or zero emissions of both air pollutants and greenhouse gases. The predicted

shortage of the crude oil encouraged the search for substitutes for petroleum derivatives

which lead to an alternative fuel called “biodiesel”. Biodiesel has proven to be able to

provide energy as per the requirement of the sectors such as agriculture, transportation,

commercial and industrial sectors of the economy (Shafiee and Topal. 2009).

Biodiesel consists of long chain of fatty acid methyl esters (FAME) which is

obtained from renewable lipids such as those in vegetable oil. The major element of

vegetable oil is triacylglycerol (TAG) and also known as triglycerides. Edible oils for

example sunflower and corn oil are considered to be used for biodiesel production but

the unstable prices of edible oils and high demands for alimentary needs caused research

opted to non-edible oil as the raw material of choice (Yusup and Khan. 2010). Using

vegetable oil as feedstock for the production of biodiesel causes a major worry over the

struggle in the food supply for the future. So to avoid the issue, biodiesel production

must be done using non-edible oil as raw material and not to mention the reduction of

2

energy required during transesterification process by using catalyst. The non-edible

vegetable oil used in this study is rubberseed oil (RSO)

The RSO has high free fatty acids (FFAs) content, which means that cockle

based heterogeneous catalyst is desirable for usage. Heterogeneous base catalysts have

pluses of being recycled, noncorrosive, have better tolerance to water and FFAs in

feedstock, improve biodiesel yield and purity, a simpler purification process for glycerol

and are easy to separate from the biodiesel product (Kawashima et al. 2008). The cockle

is processed so the calcium oxide (CaO) can be extracted and used as catalyst. The use

of biodiesel replacing the conventional diesel would slow the development of global

warming by reducing the emissions of sulphur, hydrocarbon and carbon oxides. Because

of economic benefits and more power output, biodiesel is often blended with diesel fuel

in ratios of 2, 5 and 20% (Vasudevan and Briggs. 2008). In Malaysia B7 biodiesel was

implemented where 7% of biodiesel is blended with 97% of pure diesel. The carbon

dioxide emission can be minimized by increasing the ratio of biodiesel compared to

diesel (Fukuda et al. 2001).

Optimizing is improvement on the performance of a system, a process, or a

product so that the maximum value from the source can be obtained. The term

optimization has been commonly used in analytical chemistry as a method of finding out

circumstances at which to apply a practice that provides the best possible outcome

(Bezerra et al. 2008). The optimization of analytical procedures has been carried out by

using multivariate statistic technique which is response surface methodology (RSM).

Response surface methodology is a collection of mathematical and statistical methods

that depends on the fit of a polynomial equation to the experimental data, which must

describe the behaviour of a data set with the objective of making statistical previsions.

RSM can be well utilized when a response or a set of responses of interest are inclined

by several variables.

Biodiesel production is gaining more and more relevance due to its

environmental benefits and its ability to blend in with regular diesel and it is produced

3

from renewable and its sustainability. In future, biodiesel will be one of the leading

energy sources for all sectors of the industry.

1.2 PROBLEM STATEMENT

As the usage of innovation such as in diesel engine, power plant etc. grows

rapidly, the demand for diesel has increased. The resource for diesel is from petroleum

and it is not a renewable energy. The real problem lies on the production of the biodiesel

where the yield of biodiesel achieved is low which results in the requirement of more

raw materials which is rubber seed oil and more time. Biodiesel production models that

have been designed previously vary a lot. So to obtain the optimum productivity of

biodiesel, a standardized model with optimized process parameters is a minimum

requirement so that raw material requirement and time consumption can be minimized.

This study is done to optimize the biodiesel production process so that the yield can be

increased. Moreover the existing biodiesel plant is complex, high in price and requires

high work rate. Hence the small capacity biodiesel production is essential, so that the

optimization process of biodiesel can be done effectively. Catalyst preparation is critical

process parameters because catalyst plays an important role in biodiesel production

where different catalyst preparation will result in different effects on biodiesel yield and

alter the physical properties of the end product.

4

1.3 PROJECT OBJECTIVE

This report is obliged according to the title of the project which is Optimizing

Biodiesel Production from Rubberseed Oil using conventional method. Before

conducting the project study, objectives of this study have to be defined clearly and

specifically. This is very essential in order to carry out this study successfully. The

objectives of this study are:

1. To produce biodiesel from rubber seed oil using waste heterogeneous catalyst

(cockle) and conventional method.

2. To statically evaluate and optimize the yield of the biodiesel production using

Response Surface Method (RSM).

3. To study the feedstock characteristics such as FFAs and fatty acid composition

that may influence the final properties of the biodiesel.

1.4 PROJECT SCOPE

The scope of the study is defined so that a specified study can be conducted and

the study does not go off the track of the study. Scope also ensures that the study is

parallel with the objective. The scope of this study is:

1. The raw material used to produce biodiesel is Rubber seed oil.

2. The biodiesel production involves only Acid Esterification and Base Catalysed

Transesterification process.

3. Heating equipment used for Acid Esterification and Base Catalysed

Transesterification process is Constant temperature electric heater with magnetic

stirrer.

4. The type of base catalyst used in Base Catalysed Transesterification process is

Cockle.

5

CHAPTER 2

LITERATURE REVIEW

2.1 RUBBER SEED OIL

Rubber seed is another source that nature has to offer where it can be obtained

from rubber tree. From the rubber seeds, rubber seed oil can be extracted. Rubber seed

doesn’t involve in the latex manufacturing process and usually the rubber seed is not

fully utilized even though the processed oil has the potential that can be utilized in

various applications. In Malaysia, rubber plantation is vast hence it is an abundant

source in our country. According to Association of Natural Rubber Producing Countries,

it is estimated rubber seed production in Malaysia to be 1.2 million metric tons (Ng et al.

2013). The advantages of using rubber seed as the raw material to produce biodiesel is

that the rubber seed is a poisonous seed and the oil produced is non-edible. This means

that the usage of rubber seed for biodiesel production can be large and will no cause

problem such as supply shortage unlike the edible oil. Besides that, by choosing rubber

seed oil as the raw source for biodiesel production, there is no requirement for

cultivation of new rubber plantation because there is large plantation existing in Asia

and Africa due to the demand for latex production. At the same time, the production of

biodiesel will help the farmers to be able to make extra income by collecting and selling

the rubber seed which previously has less function.

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2.2 BASIC CHEMICAL REACTIONS

Vegetable oils are esters. Esters which are called as triglycerides are composed

of unsaturated and saturated monocarboxylic acids with the trihydric alcohol glyceride

(Leung et al. 2010). With the presence of a catalyst these esters are able to act in

response with alcohol. This process is called transesterification. The simplified form of

its chemical reaction is presented in equation where R1, R2, R3 as shown in Figure 2.1

(at the end of section 2.2) are long-chain hydrocarbons, sometimes called fatty acid

chains. A study revealed that rubber seed comprises of 38.9% oil. The oil contains

80.5% unsaturated fatty acids and 18.9% saturated fatty acids. The unsaturated fatty

acids are mainly comprised of three acids which are Linoleic acid with a content of

39.6%, second is Oleic acid with content of 24.6% and finally Linolenic acid with

16.3% of content. As for saturated fatty the major acids are Palmitic acid with 10.2% of

content and Stearic acid with a content of 8.7% (Ramadhas et al. 2005). During

transesterification the triglyceride will breakdown gradually to diglyceride, and then to

monoglyceride, and finally to glycerol where at each breakdown step 1 mol of fatty ester

is released (Hanna and Ma. 1999). The preferable alcohol for producing biodiesel is

methanol due to its low cost. Vegetable oils may contain small amounts of water and

FFAs. The FFAs can react with alcohol to form ester which is the biodiesel by a reaction

called acid-catalysed esterification which very useful for handling oils with high FFAs.

For an alkali-catalysed transesterification, the alkali catalyst that is used which in this

study is methanol (CH3OH) will react with the FFAs to form soap and water.

7

Figure 2.1: Schematic view of the chemical reaction during transesterification

(Ngamcharussrivichai, C. et al., 2010)

2.3. BIODIESEL PRODUCTION PROCESSES

2.3.1 Raw Material properties

The rubber seed oil that will be used for production of biodiesel must be studied

first so that the physical properties and chemical properties of the oil can be found out.

These properties are important because it have influence in the quality of biodiesel that

will be obtained. In this study, the physical properties that studied for the rubber seed oil

are density and kinematic viscosity. As for the chemical properties, acid value (AV),

saponification number, and iodine value is studied. This study also prioritizes the

chemical properties of the rubber seed oil because it plays a larger role in the yield and

8

properties of the produced biodiesel. Section 2.3.1.1 until 2.3.1.5 explains in detail

regarding the chemical properties of the rubber seed oil.

2.3.1.1 Gas Chromatography (GC)

GC is a common analytic method used in many research fields as identification

and quantitation equipment for compounds in a mixture. The reason that GC is more

favourable technique is because the detection of compound with very small quantities is

possible with GC. A small amount sample of the mixture that is being analysed will be

injected into the GC machine via a syringe. The mixture usually brought into the GC

machine in liquid form where at latter stage in the column oven the components of the

mixture are heated and instantly vaporize. Before the mixture is heated, a carrier gas is

injected to the mixture to be tested. The carrier gas only serves a sole purpose which is

to help the gases in mixture to move through the column after heated and vaporized. The

most common carrier gases are nitrogen gas (N2), hydrogen gas (H2), and helium gas

(He). The carrier gases must be chemically inert and has very high purity whereas lack

of the two criteria will result in column bleeding and destroy the column. The column is

made up of thin glass or metal tube where the tube is filled with liquid that has high

boiling point. The column is placed in a column oven that functions as an adjuster to the

column temperature to a determined and reproducible value. The absorption and

separation occurs as the mixture travels through the column where the components

separate out. Each component emerges one by one at the end of the column and passes

an electronic detector. The electronic detector identifies each component and a peak on a

chart is printed for each component resulting in a final chart that has a series of peaks

that represents to every substance that exists in the mixture. The process explained

above is represented by the flow chart in Figure 2.2.