UNIVERSITI PUTRA MALAYSIA

TEXTURAL, IMAGING AND HEAT TRANSFER STUDIES OF OIL PALM FRUITLETS IN CONTINUOUS STERILSER

SAAD ABDULAMIR ABBAS

FK 2008 48

TEXTURAL, IMAGING AND HEAT TRANSFER STUDIES OF OIL PALM FRUITLETS IN CONTINUOUS STERILSER

By

SAAD ABDULAMIR ABBAS

Thesis Submitted in Fulfillment of the Requirement for the Degree of Doctor Philosophy in the Faculty of Engineering Universiti Putra Malaysia

January 2008

Dedication

To him who give me the patient, wisdom, power and guidance, I thank him, the most merciful, ALLAH (s. w. t.)

I sincerely dedicate the fruits of my effort to my dearest parents who really plant in me

the principal of love, care, and respect. I hope ALLAH will give me the health and welfare to do my duty towards them.

I dedicate also this work to my continuity, lovely children Saif and Farah, who are

worth a lot to me…..

ABSTRACT

Abstract of theses presented to the Senate of Universiti Putra Malaysia in fulfillment of the requirement for the degree of Doctor of Philosophy.

TEXTURAL, IMAGING AND HEAT TRANSFER STUDY OF OIL PALM FRUITLETS IN CONTINUOUS STERILISER

By

SAAD ABDULAMIR ABBAS

January 2008

Chairman: Associate Professor Dr. Thomas S. Y. Choong, PhD

Faculty: Engineering

Commercial palm oil mills in Malaysia are using batch sterilisation process, which had

considerable disadvantages and negative impact on palm oil mill industry. The aim of the

study is to investigate some aspects of continuous steriliser, which may help in reducing

the high operational cost of palm oil mills and provide a possibility of minimizing the oil

lost that escape with effluent in which rendering the yield of oil and impacting

environment. Sterilisation has a direct effect on textural properties of palm oil fruitlets.

The level of sterilisation effect is proportional to the amount of heat applied on the

process. A significant changes of certain parameter was observed and documented during

this work.. Sterilisation causes softening of fruitlets texture and the degree of softening is

proportional to the level of thermal treatment. Intensive work was carried out to

determine textural analysis of the fruits and comparing the result with the sterilised

samples that were collected from commercial mill. Different residence times were

applied to investigate the changes in textural properties. Average values of fracturability,

hardness and adhesiveness of abscission layer of sterilised fruitlets were measured using

laboratory fabricated steriliser. Reading of these parameters are; 9 (gram force), 304

(gram force) and -8 (gram force. second), respectively. Standard values of fracturability,

hardness and adhesiveness of mesocarp of sterilised fruitlets were 11.3 (force gram), 192

(force gram) and -5.7 (gram force. second), respectively. Comparing with fracturability,

hardness and adhesiveness of abscission layer of fresh fruitlets of 23 (gram force), 1113

(gram force) and -15 (gram force. second), respectively. Standard values of hardness and

cohesiveness of palm kernel nut of sterilized fruitlets were found to be 5293 (gram force)

and 0.66 respectively. Compare with hardness and cohesiveness of palm kernel nut of

fresh fruitlets of 15700 (gram force) and 0.94, respectively. It was observed from

monitoring behavior of fruits texture during sterilisation that optimization process of

residence time is fully complies with the objectives of sterilisation. Values of

fracturability of abscission layer obtained from applying residence times of 30, 40, 45, 50

and 55 minutes were 10.7, 10.2, 9.9, 8.1 and 7.6 (gram force), respectively. Hardness

values of abscission layer of 371, 265, 221 and 197 (gram force) were recorded when

applying residence time of 40, 45, 50, and 55 minutes respectively. Values of

adhesiveness of abscission layer of (-16.1), (-16), (-13), (-10.7) and (-8.4) (gram force.

second) of residence times of 30, 40, 45, 50 and 55 minutes respectively were recorded.

Hardness values of mesocarp of 302, 266, 205, and175 (gram force) were recorded with

residence time of 40, 45, 50 and 55 minute respectively. Adhesiveness values of

mesocarp of (-1.6), (-1.1), (-1.1), (-1.1) and (-0.97) (gram force. second) are obtained

from applying residence time of 30, 40, 45, 50 and 55 minutes, respectively. Values of

fracturability for the mesocarp are 11.6, 11, 10.2, 9.4 and 9 (gram force) were obtained

from applying residence times of 30, 40, 45, 50 and 55 minutes respectively. Hardness

and cohesiveness of fresh and sterilised palm kernel nut were investigated also. Hardness

values of palm kernel nut of sterilised fruitlets are 11800, 8330, 7231, 5651, and 4516

(gram force) were obtained when applied the same residence times. Cohesiveness values

of palm kernel nut of sterilised fruitlets are 0.82, 0.73, 0.71, 0.66 and 0.56 were obtained

when applying same residence time also. A correlation between residence time and

textural properties helps in the prediction of process optimization. The fruits normally

reached the mills in different ripeness categories. Oil content and color of fruits are also

not of same categories. Fruit color was observed in this study to be an excellent indicator

on the oil content. Color criteria produced very good correlation on ripeness level.

Intensive experiments were carried throughout in this study to establish a correlation

between oil content and color of fruit. An emphasis was paid on red color band and oil

content exhibits a regression value (R2) of 0.86. Color of fruits was measured in terms of

digital number configuration. To verify the results obtained experimentally, a numerical

and analytical simulation was developed. Models are proposed to solve heat transfer

problems in sterilisation tunnel. Heat transfer model was developed under transient

condition with constant fruit properties and no heat generation and the fruit was

considered of spherical geometry. The model predicts temperature distribution at the

center of fruit and its variation with time. Experimentally it was found that fruit needs to

reside 47 minutes inside the sterilisation tunnel to reach 106 ºC which is the desired

temperature to reach at the surface of palm kernel nut. Whereas residence time of 45 and

49 minutes were found to complete the required thermal treatment cycle using analytical

and numerical simulation, respectively.

ABTRAK

Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai memenuhi keperluan untuk ijazah Doktor Falsafah

KAJIAN TEXTUR, PENGIMEJAN DAN PEMINDAHAN HABA BUAH KELAPA SAWIT DALAM PENSTERIL BERTERUSAN

Oleh

SAAD ABDULAMIR ABBAS

Januari 2008

Pengerusi : Profesor Madya Dr. Thomas S. Y. Choong, PhD

Fakulti : Kejuruteraan

Kilang minyak sawit komercel di Malaysia menggunakan proses pensteril berkelangat,

dimana melibatkan kekurangan dan impak negative dalam industri minyak sawit.

Matlamat penyelidikan ini adalah untuk meskaji dan mengetahui beberapa aspek dalam

perstil berturskan, dimana ia membantu dalam mengurangkan kos perseluaran minyak

sawit dan kemungkinan mengurangkan kehilangan minyak yang dibuang dengan bahan

yang boleh menghasilkan minyak dan kesan terhadap alam sekitar. Eksperimen ini dibuat

menggunakan persteril bertaretan, dengan menjangkakan penambahan mutu minyak

kelapa sawit. Pensteril mempunyai kesan ke atas tekstur buah sawit. Darjah akibat kesan

itu adalah berkadaran dengan jumlah kepanasan yang diberi. Semasa proses steril,

sesetengah tekstur jelas menunjukkan perubahan, steril menyebabkan tekstur buah

menjadi lembut, dimana memerlukan darjah yang berlainan. Darjah untuk melembutkan

adalah berkadaran kepada tahap rawatan terma. Eksperimen yang intensif telah dibuat

untuk menentukan analisis fizikal buah dengan membandingkan keputusan dengan

contoh steril yang diambil dari kilang. Cara yang mengikut garis panduan telah

digunakan untuk menentukan nilai kesegaran dan buah yang di steril sebagai panduan

untuk menjayakan kesinambungan proses steril. Ia dibuat di tempat yang berlainan untuk

memperolehi perubahan dalam tekstur. Nilai yang digariskan dalam kekerasan fraktur

dan adhesiveness of abscission lapisan buah yang disteril adalah 9 gram, 304 gram dan -8

gram. Berbanding dengan nilai pecahan, kasar dan lekatan buah segar dari 11 gram, 2034

gram dan -88 gram saat. Nilai standar pecahan, kasar dan lekatan mesocarp dari buah

yang di steril adalah 11.3 gram, 192 gram dan -5.7 gram saat. Berbanding dengan

pecahan, kasar dan lekatan lapisan buah segar dari 23 gram, 1113 gram dan -15 gram

saat. Nilai standard kasar dan kehalusan isi buah kepala sawit di mana di jumpai menjadi

5293 gram and 0.66 gram. Berbanding dengan kekasaran dan cohesiveness buah kelapa

sawit segar dari 15700 gram dan 0.94. Ini di lihat daripada pemantauan kelakuan tekstur

buah semasa proses steril yang optimakan proses masa ialah sama dengan objektif steril.

Nilai dari proses pecahan lapisan di dapati dari masa yang di ambil iaitu dari 30, 40, 45,

50 dan 55 minit iaitu 10.7,10.2, 9.9, 8.1 dan 7.6 gram. Nilai kasar dari lapisan abscission

dari 371, 265, 221 dan 197 gram di mana di ambil dari masa 40, 45, 50, 55 minit. Nilai

lapisan abscission dari (-16.1), (-16), (-13), (-10.7) dan (-8.4) gram saat dalam masa dari

30, 40, 45, 50, dan 55 minit yang direkodkan. Nilai kasar mesocarp dari 302, 266, 205,

dan 175 gram di rekodkan semasa kutipan masa pada 40, 45, 50 dan 55 minit. Nilai

adhesiveness mesocarp dari (-1.6), (-1.1), (-1.1), (-1.1) dan (-0.97) gram saat diperolehi

daripada masa 30, 40, 45, 50 and 55 minit setiap satunya. Nilai pecahan mesocarp dari

11.6, 11, 10.2, 9.4 dan 9 didapati dari masa 30,40, 45, 50 dan 55 minit. Kasar dan

cohesiveness isi buah kelapa sawit segar dan steril di buat siasatan juga. Nilai kasar isi

buah kelapa sawit steril dari 11800, 8330, 7231, 5651 dan 4516 gram didapati apabila

masa yang di ambil pada 30, 40 ,45, 50 dan 55 minit. Nilai cohesiveness isi buah kelapa

sawit dari 0.82, 0.73, 0.71, 0.66 dan 0.56 didapati apabila masa yang diambil pada 30, 40,

45, 50 dan 55 minit. Korelasi antara masa tinggal dan maklumat tekstur membantu dalam

proses mengoptimumkan hasil. Selalunya buah-buahan akan masak di dalam kategori

kematangan yang tertentu. Kandungan minyak dan warna buah tersebut juga tidak sana

kategori. Kepelbagaian dalam kandungan minyak dan warna buah adalah berkaitan

dengan tahap kematangan buah tersebut. Eksperimen dijalankan di dalam kajian ini untuk

mendapatkan korelasi antara kandungan minyak dan warna sesuatu buah. Hubungan di

antara band warna merah dan kandungan minyak mempunyai nilai pengunduran (R2)

dari 0.86. Warna buah diukur dalam bentuk nombor digital. Untuk mengesahkan

keputusan yang didapati dari eksperimen ini, penjelmaan numeric dan analitikal telah di

bina. Model yang di cadangkan untuk menyelesaikan masalah permindahan haba dalam

terowong steril. Model permindahan haba dibina di bawah keadaan sementara dengan

buah yang tetap dan tiada haba yang terhasil dan mengambil kira geometri buah yang

berbentuk sfera. Model taburan haba mentafsirkan pada tengah buah dan variasi

mengikut masa. Ekperiment ini menjumpai buah perlu di biarkan selama 47 minit dalam

terowong steril sehingga mencecah 106 ºC di mana ia merupakan suhu untuk sampai ke

isi buah sawit. Di mana masa di antara 45 dan 49 minit merupakan masa jangkaan yang

diperlukan untuk menyiapkan pusingan rawatan haba menggunakan simulasi numeric

masing-masing.

ACKNOWLEDGMENTS

I would like to take this opportunity to express my sincere thanks to the chairman of my

supervision committee, Associate Prof. Dr Thomas S. Y. Choong for his continuous help

and support during the period of this study. Sincere thanks are extended to past

committee members: Associate Prof. Dr Fakhrul’-Razi Ahmadun and Mr. Mohd halim

Shah Ismail and to present committee members: Associate Prof. Dr Robiah Yunus and Dr

Salimaton Ali for their support, cooperation and guidance. A sincere thanks also goes to

Associate Prof. Dr Abdul Rashid Mohamed Shariff for his support and useful

contributions.

Special thanks to all staff of texture laboratory in Faculty of Food Science and technology

for their assistance during the construction of texture experimental setup. I wish to

express great thanks to Mrs. Rohaya Halim from Malaysian Palm Oil Board (MPOB) and

to all the staff of Chemical Analysis Laboratory/Department of Engineering and

Technology for their assistance during the construction of images and oil content

experiments, who has been kind enough to provide help and support, all the

encouragement and help thankfully acknowledged.

Great thanks to my dearest friend Prof. Dr Amir Hassan Khadum who really assist me in

accomplishing my work, and who never reserved any effort to support and encourage me

from the beginning until the very last of this work. I ask ALLAH (s.w.t.) to bless him and

his family.

I also wish to acknowledge the experimental and computational faculties provided by the

Faculty of Engineering during the course of work.

I also wish to express my deepest gratitude to the staff of the Graduate School for all

kinds of assistance provided to us, international students that make our life easier.

The present work is funded by MOSTI, Intensified Research Priorities Area (IRPA) (09-

02-04-032-EA001), which is thankfully acknowledge.

DECLRATION

I declare that the thesis is my original work except for quotations and citations, which have been duly acknowledged. I also declare that it has not been previously and is not currently, submitted for any other degree at UPM or any other institution.

SAAD ABDULAMIR ABBAS

Date: April 11th, 2008

This thesis was submitted to the senate of Universiti Putra Malaysia and has been accepted as fulfilment of the requirement for the degree of doctor philosophy. The members of the Supervisory Committee were as follows: Thomas S. Y. Choong, PhD Associate Professor, Faculty: Engineering Universiti Putra Malaysia (Chairman) Robiah Yunus, PhD Associate Professor, Faculty: Engineering Universiti Putra Malaysia (Member) Salimaton Ali, PhD Associate Professor, Faculty: Engineering Universiti Putra Malaysia (Member)

AINI IDERIS, PhD Professor AND Dean School of Graduate Studies Universiti Putra Malaysia Date: 8/5/2008

TABLE OF CONTENT Page DEDICATION ii ABSTRACT iii ABSTRAK vii ACKNOWLEDGEMENTS xi DECLARATION xiii APPROVAL xiv LIST OF TABLES xviii LIST OF FIGURES xix LIST OF ABBREVIATIONS xxi CHAPTER 1 INTRODUCTION 1

1.1 Palm oil mill technology 1 1.2. Sterilization process 2 1.3 Objective of study 6 1.4 Scope of the study 6 1.5 Thesis organization 7

2 LETRETURE REVIEW 8

2.1 Introduction 8

2.2 Palm oil mill processing 8 2.3 Sterilisation process 10

2.3.1 Objective of sterilisation 12 2.3.2 Steam consumption 12 2.3.3 Batch steriliser 16

2.3.4 Sterilisation by continuous system 18

2.4 Chemical changes during Sterilisation process 21 2.4.1 Effect of Sterilisation on Strippability 24

2.4.2 Effect of sterilisation on oil quality 28 2.4.3 Minor components 30 2.5 Effect of sterilisation on fruitlets texture 31

2.5.1 Softening mechanism of palm oil fruitlet’s texture 31 2.6 Imaging technique 32 2.6.1 Implementation of images technique 33

2.6.2 Digital image processing 35 2.6.3 On-line quality control 35

2.7 Previous Studies on Computer Modeling 37 2.8 Summary 38

3 METHODOLOGY EQUIPMENT, MATERIALS AND

PROCEDURES 39

3.1 Introduction 39 3.2 Equipments fabrication 40 3.2.1 System configuration 41 3.2.2 Steam generator 48 3.3 Determination of temperature-time profile of fruitlet’s center 51 3.4 Texture experiments 52

3.4.1 Standardization 52 3.5 Correlation between color and oil content 61

3.5.1 Test materials and sampling 61 3.5.2 Images capturing 62 3.5.3 Images processing 63 3.5.4 Determination of oil content by chemical analysis 65 3.5.5 Correlation between RGB color band and oil content 66

3.6 Optimization of residence time 66 3.6.1 Method 67 3.6.2 Test material and sampling 67 3.6.3 Image capturing and oil content determination 68 3.6.4 Thermal treatment 68 3.6.5 Determination of texture properties 69 3.7 Summary 69

4 RESULTS AND ANALYSIS 71

4.1 Introduction 71 4.2 Fabrication of continuous sterilisation chamber 71 4.3 Steam consumption of continuous steriliser in compare

to batch system 72 4.3.1 Batch steriliser in Dengkil mill 73 4.3.2 Continuous system of laboratory scale steriliser 74 4.3.3 Summary 75

4.4 Effect of Sterilisation on texture properties of palm oil fruitlets 75 4.4.1 Standard results (Obtained from commercial mill) 75

4.4.2 Changes in texture properties during continuous Sterilisation process 81

4.5 Image processing technique 99 4.5.1 Correlation between color and oil content 99 4.5.2 Optimization color band 100 4.5.3 Correlation between residence time and color band 102 4.6 Applications of TPA and image techniques 103 4.6.1 Conceptual of control system for continuous sterilisation

Process 107 4.6.2 Ripeness categorization system 110

5 HEAT TRANSFER AND MODELING 112

5.1 Introduction 112 5.2 Heat transfer equation 114 5.3 Analytical Simulation 122 5.4 Summary 125

6 DISCUSSIONS AND RECOMMENDATIONS 126

6.1 Introduction 126

6.2 Textural properties of fruitlet and TPA technique 127 6.3 Image processing technique 128 6.4 Modeling of heat transfer problem of palm oil fruitlet 129 6.5 Recommendations 130

REFERENCES 134 APPENDIXES 140 BIODATA OF STUDENT 178

LIST OF TABLES

Table Page 2.1 Analysis of Steam Distribution in 25 tone/hr Palm Oil Mill 14 2.2 Effect of bunch size and species on stem consumption 16 2.3 Average performance of Bukit Putri Palm Oil Mill in July 2005 20 2.4 Water loss from ripe fruit bunches during different

sterilisation peak

2.5 FFA content of fresh damaged and undamaged fruits, And sterilized damaged and undamaged fruits. 29

2.6 Carotenes and Tocopherol content of oil from various treated samples. 30 3.1 Typical composition of palm oil fruitlets bunch based on

percentage of weight 54

3.2 Setting of Texture Analyzer (TA-TX2) using 2mm flat ended probe 59

3.3 Setting of Texture Analyzer (TA-TX2) using 75mm platen aluminum probe 60

3.4 Classification of palm oil bunches regarding ripeness condition 67 . 4.1 Textural properties of fresh and sterilised palm oil fruitlets

in batch steriliser 76

4.2 Effect of sterilisation on textural properties of abscission layer 81 4.3 Residence time as an actual and estimated using Equation (4.1) 84 4.4 Summary of sterilisation effect on textural properties of mesocarp 89 4.5 The effects of sterilisation on rheological properties of palm

Kernel nut 95

4.6 Determination of oil content of each ripeness category 102

LIST OF FIGURES Figure Page 1.1 Typical palm oil mill 2 2.1 Typical palm oil mill process 10 2.3 Steam distribution in a typical palm oil mill 13 2.4 Material balance of typical palm oil mill based on

100 tone of FFB 10 2.5 Typical horizontal Steriliser using batch system 17 2.6 Schematic diagram of MPOB continuous sterilisation system 19 2.7 Products element of FFB before sterilisation 22 2.8 Possible products after sterilisation 23 2.9 Palm oil fruitlet 25 2.10 Cross section of palm oil fruit 25 2.11 Diagram represents cross section of palm oil fruit 26 2.12 Hydrolysis of carbohydrate (polysaccharides) 27 2.13 Illustration of the implantation of a machine vision

system on a production line, including process control option 36

3.1 Rotary gate supplied with eight blades 44 3.2 Diagram shows blade edges covered with rubber skirt to

reduce Steam escaping 45 3.3 Introduce steam to sterilisation tunnel using nozzles jets 46 3.4 Picture of continuous steriliser 46 3.5 Schematic diagram of the laboratory scale continuous steriliser 47 3.6 Thermal treatment include sterilisation tunnel and steam generator 49 3.7 Determination of palm kernel nut surface’s temperature using

scanner 51 3.8 Illustration of the structure of the palm oil fruitlet 53 3.9 Fresh fruit bunch (FFB) 54 3.10 Cross section in fresh fruit 54 3.11 2mm flat-ended Needle probe 56 3.12 75mm compression platen 56 3.13 The location points where the penetration force applied

to fresh and sterilised palm oil fruitlets 57 3.14 Relationship between textural properties of fruitlets and

objectives of sterilisation process 58 3.15 Images capturing system 63

4.1 Effect of using rubber skirt on the performance of rotary gates of continuous sterilisation process in an empty load operation 72

4.2 Schematic diagram of maximum allowable volume for fruitlets 74 4.3 Rheological properties of fresh abscission layer 77 4.4 Rheological properties of abscission layer of batch system 77 4.5 Rheological properties of Fresh mesocarp 77 4.6 Rheological properties of mesocarp of batch system 77 4.7 Rheological properties of fresh palm kernel nut 80 4.8 Rheological properties of commercial sterilised palm kernel nut 80 4.9 Effect of Sterilisation on fracturability of abscission layer 83 4.10 Effect of Sterilisation on hardness of abscission layer 86 4.11 Effect of Sterilisation on adhesiveness of abscission layer 88 4.12 Effect of Sterilisation on fracturability of mesocarp 90 4.13 Effect of Sterilisation in hardness of mesocarp 92 4.14 Shows the effect of Sterilisation on adhesiveness of mesocarp 93 4.15 Effect of sterilisation in hardness of palm kernel nut 96 4.16 Effect of sterilisation in cohesiveness of palm kernel nut 97 4.17 Correlation between color bands in digital number

and oil content of palm oil mesocarp 100 4.18 Correlation between residence time and digital number 104 4.19 Correlation between oil content and residence time 106 4.20 A block diagram of continuous steriliser provided with color

verification to regulate residence time for optimum sterilisation of palm oil mill using images technique 109

4.20 Diagram shows utilization of texture and image technique to optimize and control continuous sterilization process 111

5.1 Interior node of unsteady state heat transient conduction of palm oil fruitlet 113

5.2 The flow chart of palm oil fruitlet heat transfer simulation 119 5.3 Computer program for palm oil fruitlet heat transfer simulation

using Visual basic 121 5.4 Analytical and numerical simulation for temperature-time

profile on the center of palm oil fruitlet (Diameter taken as 40mm) 125

BBREVIATIONS

Symbol meaning Unites

A Area m2

Ad Adhesiveness gram seconds

Av Average Unit less

Co Cohesiveness Unit less

pC Thermal heat capacity kJ/kg. K

CPO Crud palm oil -

DN Digital number Unit less

EFB Empty fruit bunch -

EWL Equivalent Water Loss %

FFB Fresh Fruit bunch -

FFA Free fatty acid %

FAC Fatty acid compositions -

Fr Fracturability gram

FS Fresh fruitlets sample -

H Hardness gram

MC Relative oil content %

K Thermal conductivity W/m. K

PKO Palm kernel oil %

r radius m

SS Standard sterilized fruitlets -

SD Standard deviation unit less

T Temperature °K

t Time Minutes

ρ Density kg/m3

α Heat transfer coefficient W/m2 .k

CHAPTER 1

INTRODUCTION

1.1 Palm Oil Milling Technology

The spectacular growth of the palm oil industry in Malaysia since the 1960s has led to

refinement in palm oil milling technology that have facilitated simplified operation and

easy maintenance, larger-scale operation, lower operating and maintenance costs and

lower product losses (Sivasothy et al., 1997).

Currently there are about 330 palm oil mills operating in Malaysia. Even though the

milling technology can be somewhat different but they are similar in nature. Figure 1.1

shows the typical process flow diagram in a mill (Sivasothy et al., 1992b). There has

been no fundamental change in the milling process itself since the Mongana research in

1955. About 10% of the palm oil and palm kernels are currently lost during processing.

Fine-tuning the conventional processes, using techniques such as two-stage stripping

and pressing, can reduce the losses. Most of the losses, however, cannot be avoided

using conventional mechanical extraction techniques, thereby making it necessary to

investigate the use of new extraction processes. In the past, there has been a general

lack of interest in completely different processing techniques. The design of mills was

also largely based on rule-of-thumb (Sivasothy et al., 1993).

1

Figure 1.1: Typical Palm oil mill (Adopted from PORIM, 1989)

2