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PRODUCTION OF BIODIESEL FROM CRUDE PALM OIL

(CPO) AND WASTE COOKING OIL (WCO) THROUGH

TRANSESTERI FICATION METHOD

BY:

SITI KARTINA BINTI ABDUL KARIM

NOVEMBER 2010
http://www.pdfcomplete.com/cms/hppl/tabid/108/Default.aspx?r=q8b3uige22


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Tarikh : 1 November 2010

No. Fail Projek : 600-RMI/ST/5/3/Rst (30/2009)

Penolong Naib Canselor (Penyelidikan)

Institut Pengurusan Penyelidikan

Universiti teknologi MARA

40450 Shah Alam

Y. Bhg. Prof.,

LAPORAN AKHIR PENYELIDIKAN PRODUCTION OF BIODIESEL

FROM CRUDE PALM OIL (CPO) AND WASTE COOKING OIL (WCO)

THROUGH TRANESTERIFICATION METHOD

Merujuk kepada perkara di atas, bersama-sama ini disertakan 2 (dua) naskhah

Laporan Akhir Penyelidikan bertajuk Production of Biodiesel from Crude Palm Oil

(CPO) and Waste Cooking Oil (WCO) through Transesterification Method .

Sekian, terima kasih.

Yang benar,


Ketua Projek Penyelidikan


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PROJECT TEAM MEMBER


Team Leader

......................................................................

Signature


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Acknowledgements

The team is indebted to the following groups and individuals who have made this

research project successful. My heartfelt thanks go to:

Prof. Dr. Saifollah Abdullah

Dean, Fac. of Applied Sciences

Dr. Siti Halimah Sarijo

Head of Program (AS 225)

Dr. H.N.M. Ekramul Mahmud

Fac. of Chemical Engineering

and

Academic and non academic staffs of the faculty, who have lent their hands in

helping to complete the research project.


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Table of ContentsList of Tables ..................................................................................................................... vii

List of Abbreviations......................................................................................................... viii

Abstract .............................................................................................................................. ix

Chapter 1............................................................................................................................ 1

1.1 Problem Statement............................................................................................... 1

1.2 Significance of Study........................................................................................... 2

1.3 Objectives of Study.............................................................................................. 3

Chapter 2............................................................................................................................ 4

2.1 Palm Oil.............................................................................................................. 4

2.1.1 Chemical Composition of Palm Oil.............................................................. 4

2.1.2 Physical Properties of Palm Oil.................................................................... 6

2.1.3 Palm Oil as Fuel Substitute.......................................................................... 7

2.2 Transesterification Process................................................................................... 9

2.2.1 Acid-Catalysed Process ...............................................................................10

2.2.2 Base-Catalysed Process ...............................................................................11

2.2.3 Enzyme-Catalysed Process ..........................................................................14

2.3 Biodiesel.............................................................................................................14

2.3.1 Properties of Biodiesel ................................................................................15

2.3.2 Engine Performance Tests ...........................................................................18

Chapter 3 ...........................................................................................................................19

3.1 Materials.............................................................................................................19

3.1.1 Chemicals Used..........................................................................................19

3.1.2 Palm Oil Samples ........................................................................................19

3.2 Experimental Methods ........................................................................................20

3.2.1 Preparation of Palm Oil Samples .................................................................20

3.2.2 Transesterification Process ..........................................................................20

3.4 Product Analysis .................................................................................................21

Chapter 4 ...........................................................................................................................23

4.1 Yield of Biodiesel ...............................................................................................23

4.2 Methyl Ester Composition in Biodiesel ...............................................................25


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List of Tables

Table No. Title Page

2.1 Major Fatty Acids Composition in Palm Oil 5

2.2 Physical Properties of Palm Oil 6

2.3 Standard Specifications for Biodiesel Fuels(B100) Blend Stock for Distillate Fuels (ASTM

D6751)

16

2.4 European Standard for Biodiesel (EN 14214) 17

3.1 Chemicals Used in Transesterification 19

3.2 Conditions for GC 22

4.1 Yield of Biodiesel from CPO and WCO 23

4.2 Compositions of Major Components in Biodiesel 26


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List of Abbreviations

CPO Crude palm oil

FAME Fatty acid methyl ester

FFA Free fatty acid

HHV Higher heating value

RBD Refined, bleached, deodourised

WCO Waste cooking oil


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Abstract

Conversion of palm oil to fuel is one way to add value to waste and also resources of

palm oil. Palm oil can be changed to biofuel through several ways, the simplest and

most widely used is transesterification. Crude palm oil (CPO) and waste cooking oil

(WCO) is chosen to be the feedstock in order to reduce the cost of feedstock used.

The yield and composition of biodiesel produced from these sources are compared to

identify which one is the better source. Three different sources of WCO and one

sample of CPO are used for transesterification. The sources of WCO are CafeKKUiTM, McDonalds (Section 2) and a fried banana stall (Section 2). The results

showed that the yield of CPO (97 wt%) is very similar with the yield of all WCO

samples, which is in the range of 93-98 wt%. However, the methyl ester composition

of biodiesel from CPO has a higher value of C16 and C18 compared to the WCO

samples. Further researches on the physical properties of biodiesel produced, cost

implication of the feedstock and alternative feedstocks are needed in order for these

researches to be viable for industry purposes.


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the new standard for carbon emission from plant-oil based fuels is 35% less

than fossil fuels (Palm Oil HQ Pty Ltd., 2009). Thus, considerable effort still

needs to be done in order to find a suitable feedstock for the conversion of

palm oil to biodiesel which can meet the cost and environmental criteria for

its possible worldwide usage.

1.2 Significance of Study

Biodiesel produced from plant oil can be used as an alternative to fossil fuels

due to its similar characteristics to fossil fuels. The testing done by Malaysian

Palm Oil Board (MPOB) shows that Malaysian palm oil biodiesel had

achieved the standards set by the European Standards for Biodiesel (EN

14214) and American Standards Specifications for Biodiesel Fuel (ASTM

D6751) (Cheng, Choo, Yung, Ma, & Basiron, 2004). Therefore, the potential

use of plant oil-based fuels can reduce the dependency on fossil fuels.

Aside from similar physical properties, plant oil-based fuels do not contribute

to the net increase of carbon dioxide emission in the atmosphere. This is

because if the palm oil trees are replanted after being harvested for production

of fuel, the carbon dioxide is returned back to the cycle of growth. The net

carbon dioxide emission would be equal to zero. Other benefits for the

environment include the reduction in smoke emission and exhaust odour. It


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can also be used as blend to decrease sulfur emission and aromatics (El

Bassam, 1998).

The cost factor that hinders the commercial use of plant oil-based fuels can be

lowered by careful selection of feedstock that has the lowest price and is

available readily. Thus, crude palm oil (CPO) and waste cooking oil (WCO)

is chosen in order to determine their suitability as a cheap feedstock to

produce biodiesel.

1.3 Objectives of Study

The objectives of this research are:

a) To compare the yield of biodiesel produced from crude palm oil (CPO)

and waste cooking oil (WCO)

b) To analyse the methyl esters produced from transesterification of crude

palm oil (CPO) and waste cooking oil (WCO)


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Chapter 2

Literature Review

2.1 Palm Oil

Palm oil is obtained from the mesocarp of the palm fruit. It contains

approximately 50% saturated fat and 50% unsaturated fat. Due to such a

unique charateristic, palm oil may be separated under controlled thermal

conditions into two components, a solid form (palm stearin) and a liquid form

(palm olein). It is this chemical composition that defines the chemical and

physical characteristics of palm oil.

2.1.1 Chemical Composition of Palm Oil

Triglycerides form the major component present in palm oil. The remainder is

composed of less than 0.5% diglycerides, 0.1% free fatty acids (FFA), 0.3%

sterols, 0.1% tocopherols and phospholipids and pigments at ppm level.

Fatty acid is long chain monocarboxylic acid that constitutes of 2 to 30

carbon atoms but C16 and C18 are the most commonly found (Hart, 1987).

Fatty acid can be classified into saturated and unsaturated fatty acid.

Saturated fatty acid is usually straight-chained with even number carbon


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atoms. Unsaturated fatty acid is limited to C16and C18with 1, 2 or 3 double

bonds.

Fatty acids can be present in free form as free fatty acids (FFA) or combined

with other molecules to form ester. Mostly the esters formed are from

glycerols with all the hydrogen in the hydroxyl groups in the glycerol

molecules replaced by fatty acid chain via the acid carboxylic ends (Chong,

1993).

For Malaysian palm oil, the chain lengths of the major fatty acids present in

the triglycerides fall within a very narrow range from 14 to 18 carbons as

shown in Table 2.1.

Table 2.1: Major Fatty Acids Composition in Palm Oil (Basiron, 1996)

Fatty Acid

(Carbon:Double-Bond)

% of Total

Mean Range Observed

Myristic Acid (14:0) 1.09 0.9-1.5

Palmitic Acid (16:0) 44.02 41.8-46.8

Stearic Acid (18:0) 4.54 4.2-5.1

Oleic Acid (18:1) 39.15 37.3-40.8

Linoleic Acid (18:2) 10.12 9.1-11.0


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Apart from triglycerides, other cmponents in palm oil are sterols, tocopherols,

phospholipids and pigments. All these components constituted less than 1%

of oil; nevertheless they play a significant role in the stability and refinability

of the oil. Crude palm oil (CPO) contains tocopherols and tocotrienols, which

are antioxidants and provide some natural oxidative protection to the oil.

2.1.2 Physical Properties of Palm Oil

The physical properties of fatty acid depend on the chain lengths and the

degrees of unsaturation. For saturated fatty acid, melting point increases with

the number of carbon atoms. However, for unsaturated fatty acid the melting

point decreases with the increase of double bonds. Some of the physical

properties for fatty acids are summarised in Table 2.2.


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Table 2.2: Physical Properties of Palm Oil (Perry, Green, & Maloney, 1998;

Weast & Astle, 1985)

Fatty Acid Molecular Weight Melting Point (C) Boiling Point (C)

Myristic 228.38 53.9 250100

Palmitic 256.43 63 350, 267100

Stearic 284.48 71-2 360, 23215

Oleic 282.47 16.3 286100, 228-915

Linoleic 280.45 -5 229-3016

2.1.3 Palm Oil as Fuel Substitute

A number of researches have been done to convert palm oil to liquid fuel.

These researches are mostly centered in Malaysia, which produces the largest

amount of palm oil from the last three decades.

PORIM has done intensive research to convert palm oil to diesel. Ma and his

colleagues (1996) converted palm oil to methyl esters as an alternative to

diesel and tested it in large vehicles. They found that the performance of this

fuel, which is called palm diesel, is very good and the fuel is compatible with

diesel engine.

Comparative studies of palm oil methyl ester using compression ignition

engine have been jointly done by UTM, PORIM and Petronas (Azhar &


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Anuar, 1998). This study also showed that palm diesel could be used directly

in diesel engine and its performance is very similar with diesel fuel.

Production of biodiesel using crude palm oil (CPO) was shown to have

similar properties and more environmentally friendly than petroleum based

diesel. The fuel properties of biodiesel fermented with acetone, butanol and

ethanol are found to be very much like No. 2 Diesel, with higher cetane

numbers and boiling points (Crabbe, Cirilo, Genta, Kenji, & Ayaaki, 2001).

Another work by de Almeida and co-workers (2002) presented several

problems associated with direct use of palm oil as fuel, such as poor

atomisation, carbon deposits, clogging of fuel lines and starting difficulties in

low temperatures. However, they also reported better combustion when using

palm oil at temperature of 100C.

Extensive research using CPO as biodiesel by MPOB showed that the use of

CPO as feedstock to produce biodiesel does not affect engine performance

and no modifications of the engine is needed (Basiron & Choo, 2004). The

conversion of CPO to biodiesel can also be taken as a measure to stabilize the

price of palm oil. Nonetheless, the production of palm oil to fuel uses is still

under consideration due its major uses as edible oil.

Thus, another alternative to convert palm oil to biodiesel is by using palm

fatty acid distillate (PFAD) and waste cooking oil (WCO). PFAD is a by-


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product from production of refined, bleached and deodourised (RBD) palm

oil used as cooking oils, thus will utilize fully products from palm oil. The

main drawback with using both PFAD and WCO is the high content of FFA

in both oils, increasing the production steps because usually two-step process

is needed in order to convert these oils to biodiesel (Chongkong, Tongurai, &

Chetpattananondh, 2009; Yujaroen, Goto, Sasaki, & Shotipruk, 2009). High

FFA content also means that most of the conversion will be done in acidic

environment, which is more corrosive, has no reusable catalyst and high cost

of equipment (Wang, Ou, Liu, Xue, & Tang, 2006).

2.2 Transesterification Process

Transesterification is a chemical reaction involving vegetable oil and alcohol

to yield fatty acid alkyl esters and glycerol. Factors that can affect the yield of

fatty acids in transesterification include the original fatty acid composition,

free fatty acid content of the oil, type of catalyst, type of alcohol and water

content in the oil (Kusdiana & Saka, 2004; Lapuerta, Herreros, Lyons,

Garcia-Contreras, & Briceno, 2008; Banerjee & Chakraborty, 2009;

Freedman, Pryde, & Mounts, 1984). Depending on the fatty acid content and

water content in vegetable oil, the transesterification process can be

performed by using acid-catalysed, base-catalysed or enzyme-catalysed

process.


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2.2.1 Acid-Catalysed Process

The transesterification process is catalysed by Brnsted acids, preferably by

sulfonic or sulfuric acids. This process is necessary for vegetable oils

containing high free fatty acids and water content (Freedman, Pryde, &

Mounts, 1984). However, it is not preferable in industrial setting due to the

very corrosive nature of acid catalysts compared to alkali catalysts and longer

period of reaction (Wang, Ou, Liu, Xue, & Tang, 2006). The acid catalysts

give high yield of ethyl esters, but the reactions are slow and usually

accompanied by medium to high temperature to reach completion. A

comparison of transesterification with methanol, ethanol and butanol using

concentrated sulfuric acid. The reaction time needed to achieve high

conversions to alkyl esters are from 3 hours to 69 hours (Freedman, Pryde, &

Mounts, 1984). It was concluded that reaction time affected the process more

than the type of alcohol. When the reactions were done at similar temperature

(65C), similar conversions were achieved after 69 hours. This result is

supported by another work done on palm oil (Crabbe, Cirilo, Genta, Kenji, &

Ayaaki, 2001). A high yield to ester (99.7%) was found after 9 hours at 95C

while a similar yield was achieved after 24 hours at 80C. The optimised

variables for acid-catalysed transesterification of CPO were 5% (vol/wt)

sulfuric acid, temperature of 95C and 9 hours of reaction time.

The alcohol/vegetable ratio is also one of the main factors affecting acid-

catalysed process. The stoichiometric ratio of alcohol to triglyceride is 3 to 1.


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An excess of alcohol favours the product formation, but it also makes the

recovery of glycerol difficult. Therefore, an ideal alcohol to vegetable oil

molar ratio needs to be established to get the optimum product (Demirbas,

2005). Molar ratio of 6 to 1 is the most commonly reported, but ratio as high

as 40 to 1 under different experimental conditions can also yield esters

(Ramadhas, Jayaraj, & Muraleedharan, 2004; Sahoo, Das, Babu, & Naik,

2007; Crabbe, Cirilo, Genta, Kenji, & Ayaaki, 2001).

2.2.2 Base-Catalysed Process

In a base-catalysed process, the alkaline catalyst, such as KOH or NaOH is

dissolved into a short-chained alcohol. The oil is transferred into a vessel,

then the alcohol/catalyst mixture is added in. The final mixture is usually

stirred for several hours at ambient temperature (Demirbas, 2009a; Demirbas,

2009b; Ghadge & Raheman, 2005). A good transesterification process

produces two separate liquid phases, which are the ester and glycerol.

Base-catalysed transesterification proceeds at a faster rate than the acid-

catalysed process. The methanolysis of four refined vegetable oils were

investigated with 6 to 1 alcohol to glyceride molar ratios, and it was reported

that after 1 hour, all vegetable oils produced conversion between 93 to 98%.

Lower conversions were found at a lower molar ratio (Freedman, Pryde, &

Mounts, 1984). In a base-catalysed transesterification of used frying oil, it


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was found that after 1 hour, with a methanol to oil molar ratio of 4.8 to 1, the

highest yield of methyl ester was obtained (Felizardo, Corriea, Raposo,

Mendes, Berkemeier, & Bordado, 2006).

There are several factors affecting the yield of biodiesel using alkaline

catalyst, namely the molar ratios of alcohol to glyceride and temperature (Ma

& Hanna, 1999). The molar ratio of alcohol to glyceride for base-catalysed

process was usually set at 6 to 1 to achieve optimum ester yield (Freedman,

Pryde, & Mounts, 1984). Higher molar ratios resulted in higher ester

conversion in shorter time (Demirbas, 2009a). Transesterification of waste

cooking oil with methanol and sodium hydroxide with a methanol to oil ratio

of 6 to 1 was reported to yield about 90% conversion (Meng, Chen, & Wang,

2008). A high yield of 98% was obtained from similar molar ratio, to produce

biodiesel from mahua oil (Ghadge & Raheman, 2006).

Transesterification can occur at several different temperatures. Temperature

affected the reaction rate and also the yield of biodiesel (Demirbas, 2002).

Increasing the temperature, notably supercritical temperature has a favourable

effect on biodiesel yield. In transesterification of used frying oil using sodium

methoxide, the reaction temperature is maintained at 65C (Cvengros &

Cvengrosova, 2004). Leung and Guo (2006) studied the effect of reaction

temperature towards yield and reaction time. They found that the optimum

temperature is 60C, with a yield of about 88%. Other study on the effect of


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temperature in transesterification was conducted at 6 to 1 alcohol to oil molar

ratio, 1 wt% sodium hydroxide and a reaction time of 60 minutes. The yield

of biodiesel was found to be at optimum value at 50C (Meng, Chen, &

Wang, 2008). It can be inferred that transesterification can be performed at

various temperatures, from ambient temperature to the boiling point of the

alcohol used or even higher. Temperatures can give positive impact on the

yield of biodiesel and also the reaction rate (Banerjee & Chakraborty, 2009).

To some extent, the type of alkaline catalyst used plays a role in

transesterification. The effect of three different basic catalysts towards

transesterification of used frying oilsnhas been investigated by Leung and

Guo (2006). NaOH, NaOCH3and KOH were used and compared in terms of

the ester content in biodiesel. Although all three catalysts showed similar

trends on the conversion of oil, but sodium hydroxide produced the best

result. Another comparison between NaOH and NaOCH3 for

transesterification of beef tallow showed that these catalysts reached

maximum activity at 0.3% and 0.5% w/w respectively (Ma, Clements, &

Hanna, 1998). Ester conversions for the two catalysts at 6 to 1 molar ratio

were reported to be almost the same after 60 minutes (Freedman, Pryde, &

Mounts, 1984). However, sodium hydroxide was chosen widely in industry

because it is cheaper.


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2.2.3 Enzyme-Catalysed Process

Biodiesel can also be produced from enzyme-catalysed transesterification.

Transesterification of jatropha oil in solvent-free system using three different

lipases (Chromobacterium viscosum, Candida rugosa andPorcine pancreas)

illustrated that only C. Viscosum produced appreciable yield of biodiesel

(Shah, Sharma, & Gupta, 2004). The immobilisation of C. Viscosum

enhances the biodiesel yield to 71% with a process time of 8 hours at 113K.

Although this ttype of process has yet to be commercially developed, more

results on this process has been reported (Dizge, Aydiner, Imer, Bayramoglu,

Tanriseven, & Keskinler, 2009; Li, Du, Liu, Wang, & Li, 2006; Fukuda,

Kondo, & Noda, 2001). Several parameters were usually chosen to be

optimised, such as solvent, temperature, pH and type of microorganism to

determine the suitability to withstand industrial applications. Nonetheless, the

reaction yield and reaction time are still not favourable compared to base-

catalysed process.

2.3 Biodiesel

Biodiesel comes from a Greek word bio, which means life and Diesel,

courtesy of Rudolf Diesel, who tested the first diesel engine. It is defined as a

diesel-equivalent fuel derived from biological sources, such as plant oils


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(Demirbas, 2008). It also refers to a mixture of monoalkyl esters of long

chain fatty acids from renewable lipid feedstock, such as animal fat or

vegetable oil. Biodiesel usually consists of alkyl fatty acids of short chain

alcohol, with chain length of fatty acids between 14 to 22 carbons. The higher

heating values of biodiesels are comparatively high compared to other fuel.

The heating values of biodiesel are in the range of 39 to 41 MJ/kg, slightly

lower than gasoline (46 MJ/kg), petroleum (42 MJ/kg/) but higher than coal

(32-37 MJ/kg) (Demirbas, 1998).

2.3.1 Properties of Biodiesel

Biodiesels can be characterised according to several physical and chemical

properties, such as viscosity, cetane number, distillation range, ash content,

sulfur content, carbon residue, acid value and higher heating value (HHV).

The parameters are all specified through the biodiesel standard, ASTM

D6751 and EN 14214. ASTM D6751 identifies the parameters that a pure

biodiesel must meet before being used as pure fuel or blended with

petroleum-based fuels. EN 14214 is an international standard for minimum

requirements that must be met for biodiesel produced from rapeseed oil.

Tables 2.3 and 2.4 show the properties and specifications of biodiesel as

required by the standards.

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