NUT CRACKING EFFICIENCY IN RIPPLE MILL

By:

ABDUL RAZAK BIN AB HALIM

(Matrix no. : 111509)

Supervisor:

Associate Professor Dr. Roslan b. Ahmad

Industrial Supervisor:

Mr Shahrizan bin Sulaiman (Mill Manager)

June 2015

(Academic Year 2014/2015)

This dissertation is submitted to

Universiti Sains Malaysia

As partial fulfillment of the requirement to graduate with honors degrees in

BARCHELOR OF ENGINEERING (MECHANICAL ENGINEERING)

School of Mechanical Engineering

Engineering Campus

Universiti Sains Malaysia

2

DECLARATION

This works have not previously been accepted in substance for any degree and is not

being concurrently submitted in candidature for any degree .

Signed ………………………….. (Abdul Razak bin Ab.Halim)

Date …………………………..

STATEMENT 1

This thesis is the result of my own investigations, except where otherwise stated. Other

sources are acknowledged by giving explicit references. Bibliography/ references are

appended.

Signed ………………………….. (Abdul Razak bin Ab.Halim)

Date …………………………...

STATEMENT 2

I hereby give consent for my thesis, if accepted, to be available for photocopying and for

interlibrary loan, and for the title and summary to be made available to outside

organizations.

Signed ………………………….. (Abdul Razak bin Ab.Halim)

Date …………………………..

3

ACKOWLEDGEMENTS

In the name of Allah, the Most Gracious, the Most Merciful. Praise to Him the

Almighty that in His Will and given strength, I had managed to complete the Final Year

Project (FYP). First and foremost, I would like to express my sincere gratitude to my

project supervisors, Prof. Madya Dr. Roslan Ahmad and Mr. Shahrizan Sulaiman for their

valuable guidance and supervision and countless hours spent in sharing their insightful

understanding, profound knowledge and valuable experiences throughout the project.

This research could not have been completed without them who not only served as my

supervisor, but also encouraged and challenged me through the research process.

I am grateful to the Final Year Project (FYP) coordinator, Dr. Yusof bin Idroas

who had dedicatedly provided me with additional support and encouragement throughout

the project. Besides, I would also like to thank the authority of Universiti Sains Malaysia

(USM) and Kilang Miyak Sawit Kamunting Sdn.Bhd for providing me with all the

necessary facilities for the completion of this project. Last but not least, I would like to

pay high regards to all personel who have directly or indirectly support and contribute for

the success of this project. Thank you.

4

Contents

LIST OF TABLES ........................................................................................................................... 6

ABSTRACT ................................................................................................................................. 10

CHAPTER 1................................................................................................................................ 11

INTRODUCTION ................................................................................................................... 11

1.1 Research Background ................................................................................................ 11

1.2 Problem statement ................................................................................................... 15

1.3 Objectives .................................................................................................................. 16

1.4 Scope of Work ........................................................................................................... 16

1.5 Thesis Outline ............................................................................................................ 17

CHAPTER 2 ............................................................................................................................ 19

LITERATURE REVIEW ........................................................................................................ 19

2.1 Introduction .............................................................................................................. 19

2.2 Type of Nut Kernel and effect of Free Fatty Acid (FFA) ............................................ 21

2.3 Process of Kernel Palm Oil ........................................................................................ 23

2.4 Types and performance of cracker ........................................................................... 24

CHAPTER 3................................................................................................................................ 26

Materials and Methodology .................................................................................................... 26

3.1 Mechanical Testing ................................................................................................... 26

3.2 Microstructural Observation ..................................................................................... 28

3.3 Simulation (Solid work) ............................................................................................. 29

3.4 Data measurement on Ripple Mill ............................................................................ 33

5

CHAPTER 4................................................................................................................................ 35

Result and Discussion ............................................................................................................... 35

4.1Percantage of carbon in the rod ...................................................................................... 35

4.2 Maximum Load of Palm Oil Nut ...................................................................................... 36

4.3 Deformation of the Rod in Rotor .................................................................................... 39

4.3.1 Stress (Von Misses Stress) ....................................................................................... 39

4.3.2 Displacement of Deflection ..................................................................................... 41

Figure 4.10 New Distance of Baffle plate ............................................................................. 42

4.4 Nut Cracking Efficiency in Ripple Mill: ............................................................................ 43

4.4.1Cracking efficiency based on variable frequncy(Hz) speed of rotor ........................ 43

4.4.2 Cracking Efficiency based on variable of Spacing between rotor and ripple plate:

.......................................................................................................................................... 45

CHAPTER 5................................................................................................................................ 47

CONCLUSION ......................................................................................................................... 47

Appendices ............................................................................................................................... 49

Appendix 1: ........................................................................................................................... 49

Appendix 2: ........................................................................................................................... 51

Appendix 3: ........................................................................................................................... 54

6

LIST OF TABLES

Tables Pages

Table 4.1 Result Compressive horizontal testing for nut palm oil 40

Table 4.2 Result Compressive vertical testing for nut palm oil 42

Table 4.3 : Average Percentage Cracking Efficiency of Nut 51

Table 4.4 : Average Percentage Cracking Efficiency of Nut 53

7

LIST OF FIGURES

Figures Pages

Figure 1.1 Schematic Diagram of Ripple Mill 11

Figure 1.2 Rotor of Ripple Mill 13

Figure 1.3 Ripple Plate of Ripple Mill 13

Figure 2.1 Cross Section of Oil Palm Fruit 19

Figure 3.1 (a) Horizontal (b) Vertical 25

Figure 3.2 UTM Machine(Compress) 25

Figure 3.3 Nut Fruit Palm cracked 26

Figure 3.4 Desplay result 26

Figure 3.5 Rod Carbon Steel 27

Figure 3.6 Rod Fractured 27

Figure 3.7 Fractured of Rod 28

Figure 3.8 Measure the gage length 28

Figure 3.9 Scanning Electron Machine 29

Figure 3.10 Cross Section Of Carbon Steel 30

Figure 3.11 Ripple Mil 37

Figure 3.12 Inverter 37

Figure 3.13 Uncracked Nut 38

Figure 3.14 Weighter 38

8

NOMECLATURE

LIST OF SYMBOLS

English Symbols

E Young Modulus Pa

A Area

L Length m

D Diameter m

Greek Symbols

Ϭ Stress Pa

ɛ Strain -

9

ABSTRAK

Kajian kes yang dilakukan di Kilang Minyak Sawit Kamunting Sdn.Bhd,

Taiping bertujuan untuk meningkatkan penghasilan minyak sawit dengan melakukan

penambahbaikan pada mesin ‘ripple mill’. Mesin ‘ripple mill’ merupakan sebahagian

dari alatan dalam kilang sawit bertujuan untuk memisahkan tempurung dan isirong

biji sawit. Skop kajian adalah untuk mengkaji peratus kecekapan tempurong dan

isirong yang hancur. Peratus kecekapan ini dapat ditingkatkan dengan melakukan

penambahbaikan pada mesin sedia ada. Mengikut rekabentuk mesin ‘ripple mill’ sedia

ada, jangka hayat ‘ripple rod’ didapati pendek disebabkan perledingan. Antara

parameter yang dijangka memberi kesan pada peratus kecekapan tempurung dan

isirong sawit yang hancur dan peledingan ialah kelajuan optimum pemutar, jarak

sesuai antara pemutar dan plat ‘ripple’, kekuatan bahan rod dan jarak antara plat

‘baffle’. Kajian parametrik berdasarkan eksperimen dan simulasi dilakukan bagi

menentukan kecekapan peratusan tempurung dan isirong yang pecah dalam mesin

‘ripple’. Pemerhatian mikrostuktur menggunakan SEM dan ujian tegangan

menggunakan mesin UTM dilakukan ke atas bahan untuk masing-masing menentukan

kandungan dan kekuatan rod. Ujian mampatan ke atas buah sawit dilakukan untuk

anggaran beban yang ditindaki pada rod. Data dari esperimen dimasukkan dalam

kajian simulasi menggunakan SOLIDWORKS. Kajian kes yang dilakukan mendapati

faktor kelajuan optimum pemutar, jarak sesuai antara pemutar dan plat ‘ripple’,

kekuatan bahan rod dan jarak antara plat ‘baffle’ memberi kesan pada peratus

kecekapan tempurong dan isirong yang hancur.

10

ABSTRACT

The case study was carried out at Kilang Minyak Sawit Kamunting Sdn.Bhd,

Taiping aiming towards increasing the production of palm oil. This could be achieved

by improving the ripple mill machine. The ripple mill machine is part of the palm oil

factory and is used to separate the palm kernel and its shell. The scope of the study is

to investigate the efficiency of palm kernels and shell breakage. The efficiency could

be increased by improving the existing machine. Based on the design of the existing

ripple mill machine, the ripple rod has shorter shelf life due to bending of the rod.

Among the parameters that is expected to affect the efficiency of the palm kernels and

shell breakage and bending of the rods are the optimum speed of the rotor, the

distance between the rotor and the ripple plate, the strength of the rod material and the

spacing between the baffle plates. Parametric study based on the experimental and

simulation was done to determine the efficiency of the palm kernels and shell

breakage in the ripple mill machine. Microstural observation using SEM and tensile

test by using UTM were performed to determine the constituent of the material and

the strength of the rod respectively. Compression test on palm fruits is carried out to

obtain the estimated load being subjected to the rod. Data from the experimental work

is inputed in the simulation study using SOLIDWORKS software. The case study that

was carried out indicate that the optimum speed of the rotor, the distance between the

rotor and the ripple plate, the strength of the rod material and the spacing between the

baffle plates have some effect on the efficiency of the palm kernels and shell

breakage.

11

CHAPTER 1

INTRODUCTION

1.1 Research Background

In general, a palm oil mill produces crude palm oil and kernels as primary

products and biomass as secondary product1. Processes in palm oil mill includes six

parts which is palm bunches receiving, sterilizer, threshing, mashing and pressing,

crude oil clarifying and palm oil kernel recovery 2.The overview of the process is

shown in Figure 1.1.

Figure 1.1 : Palm oil mill process flow diagram

1 http://lipidlibrary.aocs.org/processing/palmoil/index.htm

2 http://www.palmoilextractionmachine.com/product/palm_oil_refinery_process/palm-oil- mill-

85.html

Ripple

Mill

12

The process is started with fruits receiving which is collecting the ripe fresh

cluster from the orchard. Then, the palm fresh fruit bunch (FFB) are airtight sterilized

in sterilizer, injecting direct steam. Sterlization or fruit cooking weakens the pulp

structure, softening it and making it easier to detach the fibrous material and its

contents during the digestion process. The high heat is enough to partially disrupt the

oil-containing cells in the mesocarp and permits oil to be released more readily. After

that the fruits are sent to the thresher. The purpose of threshing is to separate the palm

fruit from the FFB. Palm oil mill process of mashing and pressing will separate the

pulp and nut and crush the palm pulp2. The steam heater is also installed in the

masher. Palm oil mill process of oil clarifying machine-pressed crude oil first diluted

with water washing, through settlement and filtration. At this stage, the fiber material

will be removed from the oil, and then carry out continuous settlement. The whole

outcome is divided into two parts which is oil and sediment to process more. Last but

not least, palm kernel recovery press cake broken by breaking screw conveyor and

transported into the fiber separation air net and fiber polishing roller for fiber

separating2.

13

In addition, nut kernels are produced in this station where the press cake

from the digester is fed to a vertical column (depericarper) where air is channeled to

lift the fibre, thus separating the fibre from the nuts. The nuts are passed to a polishing

drum at the bottom of the depericarper, where pieces of stalks are removed. A

nutcracker cracks the nuts after the conditioning and drying process. A ripple mill is

also used instead of nut cracker. The mixture of cracked nuts and shells are separated

via a winnowing system, followed by a hydrocyclone or a clay bath.2

Palm kernel is a very important part of oil palm produce which is obtained

by cracking of palm nuts and separation of the kernels from the shell (Ajewole, 2014).

In order to produce nut cracking eficiency, a machine has to be used by cracking of

palm nut named as ripple mill (Figure 1.2). In general, the component of ripple mill

consist of the outher disc, ripple mill plate, rod bar and rotor disc3.

Figure 1.2 : Schematic Diagram of Ripple Mill

3 Refer ; http://agrindo.co.id/sparepart-ripple-mill.html

14

The ripple mill machine is placed in kernel plant station. This machine is

used to break the palm nut that regardless of the shell. The process starting with the

nuts enter the top of the mill and are impact several times between stationary plates

and the turning rotor as in Figure 1.1. The rotor imparts the velocity and the impact

forces crack the nut of palm. Besides, other functions of the ripple mill are used for

the pre-grinding of coal, plastics and chemicals prior to micro-fine grinding, coarse

animal feed grinding and other shelling or hulling applications.

To enhance the percentage palm nut cracking effficincy, the impinging

velocity that gives maximum cracking efficiency of a vertical shaft centrifugal palm

nut cracking machine are used. A nut cracking energy instrument which consists of a

hammering mass falling vertically on palm nuts placed on a base was used to

determine potential energy required to crack the nuts (Ajewole, 2014). Besides, static

impact method is another method in order to investigate into the energy demand for

cracking of palm nuts (Esua et.al, 2015) .

In this project, the focus is to determine the suitable rod material and the

spacing of the baffle plate used in the rotor of ripple mill in order to increase the shelf

life of the rod from bending and damages. In addition, parametric studies on the

optimum centrifugal speed of ripple mill and spacing or distance between the rotor

and the ripple plate will be investigated. These parameters are suspected to affect the

percentage cracking efficiency of the ripple mill machine.

15

1.2 Problem statement

The case study was carried out at Kilang Minyak Sawit Kamunting Sdn.Bhd,

Taiping. One of the main problem that affect the productivity of the palm oil is the

quality of palm kernels and shell breakage or the nut cracking efficiency. This

problem is associated with the ripple mill machine. In relation to that, the field work

found that shorter shelf life of rotor rods due to bending and damages (Figure 1.3).

Probably the bending of rotor rods might be due to the materials itself or the spacing

between the baffle plates. Other factors that might affect the quality of the palm

kernels and shell breakage are the speed of the ripple rotor and the spacing of the rotor

and the ripple plate (Figure 1.2). This assumption needs to be investigated and

verified. Hence, observation on the existing operation of the machine at the field and

getting some data for the basis of the study is necessary.

Figure 1.3 :Rotor of Ripple Mill

rod bar

Distance/ spacing

of baffle

16

1.3 Objectives

The main objective of the research is to increase the quality of palm kernels

and shell breakage or the efficiency of the nut cracking in ripple mill. This can be

accomplish through the following objectives.

1. To determine the suitable rod material and baffle spacing for use in

the rotor of ripple mill in order to increase the shelf life of the rod.

2. To assess the operation of ripple mill through parametric study which

is the speed of the rotor and the distance of the rotor and the ripple

plate.

1.4 Scope of Work

The field work is carried out at Kilang Minyak Sawit Kamunting Sdn.Bhd,

Taiping. The area of focus is on ripple mill under the Kernel Plant Station in Palm Oil

Mill. The scope of the case study is on the nut cracking efficiency to obtain data of

parametric study in ripple mill and material of rotor used in ripple mill. The

observation and data collection is done in the field whereas material testing is

performed at USM. Experimental and simulation works are carried out for validation

and comparison.

17

1.5 Thesis Outline

Basically there are five chapters in this thesis which consisted of

introduction, literature review, methodology, results and discussion, and conclusion.

Each chapter plays an important role in assisting the readers to have better

understanding about research which is carried out.

The general outline of the palm oil mill processes, the problem statement

and the objectives of the work is covered in the introduction. The percentage nut

cracking efficiency of kernel palm oil is futher elaborated in the literature review. In

addition, it will further clarify about the type of palm oil nuts and types of other

cracker used.

For methodology section it will discuss about the data collection and testing

done which include the compression load of palm oil nuts, tensile test on the rotor rod

by Universal Testing Machine(UTM). Besides that, it will also discuss about the

procedure to run simulation on the bending of rotor rod by SOLIDWORKS sofware.

Lastly, the procedure to run experiment in palm oil mill on ripple mill in Kilang Sawit

Kamunting Sdn.Bhd.

18

In the section of results and discussion, it shows all the results obtained from

the experimental works and data collection in the field. Results from silmulation

works will be validated and compared. The graph percentage of nut cracking-speed of

rotor ripple mill will be analysed and discussed. The experimental investigation and

anlysis will be concluded and evaluated in the last chapter by mapping it to the

objectives of the thesis.

19

CHAPTER 2

LITERATURE REVIEW

2.1 Introduction

Today, 4.49 million hectares of land in Malaysia is under oil palm

cultivation; producing 17.73 million tonnes of palm oil and 2.13 tonnes of palm

kernel oil. Malaysia is one the largest producers and exporters of palm oil in the

world, accounting for 11% of the world's oils & fats production and 27% of export

trade of oils & fats. The industry provides employment to more than half a million

people and livelihood to an estimated one million people.

Oil palm is the most efficient oilseed crop in the world. One hectare of oil

palm plantation is able to produce up to ten times more oil than other leading oilseed

crops. (Figure 2.1). Indonesia and Malaysia produce about 85% of the world’s palm

oil. Other producer countries include Thailand, Columbia, Nigeria, Papua New

Guinea and Ecuador.

20

Figure 2.1 : Oil Palm Efficiency vs Other Major Oil Crops

(Source: Oil World 2013) (http://www.simedarby.com/upload/Palm_Oil_Facts_and_Figures.pdf)

Nowdays, oil palm is a great economic asset (Elaeis guineensis Jacq.). It is

acclaimed to be the richest vegetable oil plant because many products can be derived

from the oil palm; this includes palm oil, palm kernel oil, palm kernel cake, fibre,

palm wine, fatty alcohol, broom,and wood plank.(Ndukwu & Asoegwu, 2010).

In additiom, palm kernel oil widely use which is the kernels are usually

processed in to obtain oil and cake. The oil is used for making soap, cosmetics,

glycerol, margarine, explosives, refined edible vegetable oil, etc (Esua et al., 2015).

21

In general, a reliable energy-related data and a new approach for the

effective design of palm kernel nut cracking machine is therefore not only necessary

but also important to revitalize the production of palm kernel in other to meet up with

ever increasing industrial demand of its oil.(Esua et al., 2015). So that, the optimal

performance of the cracker is based on cracker efficiency and kernel breakage factor.

It is a compromise between high cracking efficiency and low kernel breakage factor

or ratio.(Ndukwu & Asoegwu, 2010).

2.2 Type of Nut Kernel and effect of Free Fatty Acid (FFA)

The oil palm has many species, as stated in journal and in literature,

classified into two major species widely being cultivated; dura and pisifera. Dura is

thick shelled with thin mesocarp whereas the pisifera species is thin shelled with

thicker mesocarp (Esua et al., 2015). Eventually, in other journal stated three varieties

of oil palm namely dura, tenera and pisifera (Figure 2.2).

Figure 2.2: Type of oil palm fruits.

22

Dura is characterized by thin mesocarp, thick endocarp (shell) with generally

large kernel. The duratype is genetically homozygous and dominant for shell. It is

denoted by DD. Tenerapossesses thin mesocarp, thin endocarp with large kernel. This

is a dual-purpose palm for the production of mesocarp oil and kernel.

In addition, palm kernel contains 46% – 54% oil with a Free Fatty Acid

(FFA) of about 4% and this oil is more stable than palm oil. Cracking palm nuts to

release the kernels is a critical step that affects the quality of palm kernel oil. The

level of free fatty acids (FFA) is higher in broken kernels than in whole kernels,

therefore breakage of kernels should be kept as low as possible according to Poku,

2002.

Due to the global demand of palm kernel and its by-products, efforts have

been geared towards an improved method of palm kernel extraction. Locally made

palm kernel nut crackers are characterized by high incidence of kernel splitting. Split

kernels readily grow mould and develop high free fatty acid content which

compromises the oil quality (Esua et al., 2015).

23

2.3 Process of Kernel Palm Oil

The palm fruit is drupe oval in shape and contains kernel which is the seed

(nut). The kernel is surrounded by the fruit wall made up of hard shell (endocarp),

fibrous fruit pulp or oil bearing tissue (mesocarp) and the skin as shown in Figure 2.3

(Hamdan et al, 2000). The nuts of oil palm is dried and cracked into palm kernel and

shell, and the kernel is separated into palm kernel oil (PKO), palm kernel meal

(PKM), and water (Esua et al., 2015).

Figure 2.3 : Cross Section of Oil Palm Fruit

In addition, harvested palm bunches undergo processing stages of

sterilization, stripping, digestion, and palm oil extraction. Palm nuts and fibres are left

as residues. The nuts are dried and cracked into palm kernel and shell. It is separated

into palm kernel oil (PKO), palm kernel meal (PKM), and water (Ndukwu &

Asoegwu, 2010).

24

Last but not least, the nuts were subjected to cracking using the equipment

developed and visual observation was used to assess the level of cracking as follows;

completely cracked (CC), completely cracked with slight damage (CCD), cracked

without nut separation (CWS), unable to crack (UC) and smashed (SM) (Esua et al.,

2015).

2.4 Types and performance of cracker

Actually there many types of cracker and the oldest method of cracking is

done by placing the nut on top of the stone and striking it with another stone with an

impact force, causing the shell to split along the line of impact and the nut is

handpicked. This method of cracking is labour-intensive and less productive though

the hand-cracked kernels attract high costs due to the high grade quality oil recovered

since the level of kernel breakage is low. It also exposes the operator to the danger of

flying shells which can injured the eye or any part of the body (Ndukwu & Asoegwu,

2010).

However, the modern crackers are of two types, the hammer-impact and the

centrifugal-impact types. The hammer-impact type breaks or cracks the nut by impact

when the hammer fail on the nut, while the centrifugal-impact nut cracker uses

centrifugal action to crack the nut (Ndukwu & Asoegwu, 2010).

25

In addition, the impinging velocity that gives that maximum cracking

efficiency of a vertical shaft centrifugal palm nut cracking machine was determined in

this study. A nut cracking energy instrument which consists of a hammering mass

falling vertically on palm nuts placed on a base was used to determine potential

energy required to crack the nuts (Ajewole, 2014).

Eventually, a mathematical model for predicting the cracking efficiency of

vertical-shaft palm nut cracker was presented using dimensional analysis based on the

Buckingham’s π theorem (Ndukwu & Asoegwu, 2011). Some researchers

(Degrimencioglu, Srivastava 1996; Shefii et al. 1996; Mohammed 2002; Ndirika

2006) used the dimensional analysis based on the Buckingham’s π theorem as

veritable instrument in establishing a prediction equation of various systems.

Therefore the present study is under-taken to establish a mathematical model for

predicting the cracking efficiency of vertical-shaft centrifugal palm nut cracker using

the dimensional analysis (Ndukwu & Asoegwu, 2011).

In conclusion, the optimal performance of the cracker is based on cracker

efficiency and kernel breakage factor. It is a compromise between high cracking

efficiency and low kernel breakage factor or ratio (Ndukwu & Asoegwu, 2010).

Cracking efficiency this is the ratio of completely cracked nuts to the total nuts fed

into the hopper (Ndukwu & Asoegwu 2010). Palm kernel is an important part of oil

palm produce, which is obtained by cracking of palm nuts and separation of the

kernels from the shell.(Ajewole, 2014)

26

CHAPTER 3

Materials and Methodology

3.1 Mechanical Testing

Mechanical testing was carried by using a Universal Testing Machine

(UTM) to determine the force needed to break the nut kernel and also to determine the

properties of a rotor rod.

3.1.1 Compression test on kernel nuts

The kernal nuts were tested with horizontal and vertical position as in Figure

3.1 to obtain the maximum breakage force. Each position were tested five times to

obtain repeatability and maximum force.

Figure 3.1: Horizontal and vertical position of kernal nuts

27

Figure 3.2: Compression of kernal nut using UTM

The cracking of the kernel nut was quasi-statically compressed until the nut

breaks and cracks as shown in figure 3.3. A load displacement curves is automatically

displayed as in Figure 3.4.

Figure 3.3: Nut kernel cracked Figure 3.4: Results display from UTM

28

3.2 Microstructural Observation

Microstructural observation is carried out using SEM (Figure 3.9) to

determine the percentage of carbon in carbon steel. The specimen needs to ungergone

material preparation such as cleaning and polishing and also handling procedure.

Cross-section and the prepared sample is shown in Figure 3.10.

Figure 3.9: Scanning Electron Microscope

Figure 3.10 Cross Section Of Carbon Steel

29

3.3 Simulation (Solid work)

A linear simulation is performed using SOLIDWORKS software. The

purpose of the simulation is to understand the behavior of the rotor rod when

subjected to loading due to crushing of the kernels nut. The procedure of the

preprocessing is discussed as follows:

(i) Draw the rotor rod with diameter 250mm

D = diameter

D = 250mm

30

(ii) Select the Solidworks SimulationXpress. Then, set the system unit as

SI unit.

(iii) Apply the fixtures at the both end of the rod ie. the boundary condition

and then apply the loading or force which is the maximum force resisted by

the kernel nut ie. 1391.1 N

Select SI

unit

1391.1

31

(iv) Apply the material properties

(v) After that the simulation is run as instructed in the software.

32

(vi) After pre-processing, the simulation will undergone post-processing

where the rod is subjected to static bending.

(vii) The meshing of the rotor rod is ortogonal.

33

3.4 Data measurement on Ripple Mill

The kernel nut will passed through a ripple mill machine (Figure 3.11) with

a capacity of 9 ton/hour. The purpose is to split the kernel and shell. The speed of the

rotor is controlled by the inverter (in Hz) as shown in Figure 3.12.

Figure 3.11 Ripple Mil

Figure 3.11: The ripple mill machine. Figure 3.12: Speed inverter.

I. Firstly measure the uncracked nut kenel figure 12 below.

Figure 3.13 Uncracked Nut

34

II. Then get the percentage of cracking efficiency as below:

When runned 60Hz of ripple mill:

The mass of uncracked was measured 4.159g by using measurement (figure 13)

below:

Figure 3.14 Weighter

The percentage of uncracked nut kernel

So that the percentage of nut Cracking efficiency = 100% - 0.832%

= 99.17

35

CHAPTER 4

Result and Discussion

4.1Percantage of carbon in the rod

Figure 4.1 Shows the image of micro structure of carbon steel obtained from

scanning electron microscope. Details the material constituent is given in

appendix 3. The content of carbon in the rod is measured to be between 3.82% to

8.02%. Since the content of carbon is higher than 1.5% , the result indicate that

materials is consudered to be harden carbon steel.

Figure 4.1 micro structure of the rod carbon steel

36

4.2 Maximum Load of Palm Oil Nut

The palm oil nut is placed in horizontal and vertical position and subjected to

compression load by using UTM. The results of horizontal position the palm oil nut is

give in table 4.1.

Table 4.1 Result Compressive horizontal testing for nut palm oil

The load displacement curve for all the nut in horizontal position

superimposed together is shown in figure 4.2. About minimize load measured is about

308N and maximum load is 478N. The varietion migth be due to age of that nuts.

Figure 4.2 Result Compressive horizontal testing for nut palm oil

37

The results of compression test on palm oil nut placed in vertical

position is give in table 4.2. The displacement response is shown in figure

4.3 below.

Table 4.2 Result Compressive vertical testing for nut palm oil

Data in table 4.2 above shown that the vertical testing for nut palm oil which

is the minimum compressive load is 598.26721N. But, the vertical testing for nut

palm oil which was the maximum compressive load is 1391.10242N (appendix 2).

38

Figure 4.3 Result Compressive Vertical Testing For Nut Palm Oil

From the both test, the results indicate that the vertical position gave highest

compressive load compared to horizontal position. Hence, the maximum load of

1391N is taken to be input in SOLIDWORKS for simulation proposes.

39

4.3 Deformation of the Rod in Rotor

4.3.1 Stress (Von Misses Stress)

Figure 4.4 shows the stress contour(figure 4.4) of the rod subjected to

distributed load. Initially, the simulationis carried out for the rotor and position

147mm , between the baffle plate(figure 4.5).

Figure 4.4 Stress Contour

The result of the simulation is shows that the maximum stress is 22.585MPa affected

at both end of the rod (figure 4.4). Meanwhile the minimum stress is 0.13Mpa

observed at the middle of the rod.

Figure 4.5 Distance between baffle plate

Distance of

baffle plate

441mm

40

When the baffle distance is adjusted to 110.25mm between them the maximum

stress force to be 18.33MPa occurs at both end of the rod and for minimum stress is

0.171MPa at the middle of the rod (figure 4.7). Effect of changed the distance of the

baffle plate is the reduction in the stresses at the both end of the rod. The percentage

reduction in stress is 18.83%.

Figure 4.7 Stress Contour

41

4.3.2 Displacement of Deflection

Figure 4.8 shows the displacement contour of the rotor rod when the baffle plate is

147mm between them. The results shows that the maximum displacement or bending

of the rod 0.008598mm occurs at the middle of the rod..

Figure 4.8 Displacement Contour

However, when it was compared with distance of baffle plate 110.25mm

(figure 4.9) and with same force 1391.1N was applied on the rod. So that, the

maximum displacement is 0.003968mm occurs at the middle of the rod. As a result, it

shown that new design was decreased of the maximum of the displacement changed

from 0.008598mm decreased to 0.003968mm. The percentage is decreased 53.8% the

displacement of the new rod.

42

Figure 4.9 Displacement Contour

Figure 4.10 New Distance of Baffle plate

In conclusion, the distance between baffle plate has an effect on the stress and

displacement of the rotor rod. When the distance of the plate is reduce from the actual

distance of 147mm to 110.25mm the results were indicated reduction in stress and

displacement. It can be suggested that improvement on the ripple mill can be done by

adjusting the baffle plate.

441mm

110.25mm 110.25mm 110.25mm 110.25mm

Distance of

baffle plate

43

4.4 Nut Cracking Efficiency in Ripple Mill:

4.4.1Cracking efficiency based on variable frequncy(Hz) speed of rotor

Figure 4.11 shows the percentage cracking efficiency versus

frequency(speed) of the rotor. The experiments were carried out at different speed

between 40hz to 60hz. The present frequency used is 50Hz for mill(table 4.3)

throughput 9 Ton/Hour. Five data were measured at each frequency and an average

data of cracking efficiency is taken (Appendix 3).The characteristic in figure 4.11

shows that the presentspeed resulted percentage efficiency of the nut about 98.59%.

Swhen the rotor run at lower speed of 45Hz percentage of cracking efficiency is

97.48%. In addition, when the speed is furthered reduced to 40hz the percentage

cracking efficiency dropped to 94.75% .

Figure 4.11 Cracking Efficiency Versus Frequency

92

93

94

95

96

97

98

99

100

40 45 50 55 60

Percentage Cracking Efficiency(%) Versus Frequency of rotor(Hz)

current value

50hz

Frequency (Hz)

Cra

ckin

g Ef

fici

ency

(%

)

44

The results also indicate that when the speed increased to( Table 4.3) 55hz the

percentage cracking efficiency increased to 98.88% . The maximum speed 60hz of

rotor got highest percentage of nut cracking efficiency is 99.3%. From the figure 4.11

we can be conclude that the relationship between effect of the percentage cracking

efficiency with speed where was increase the value of frequency.

Table 4.3 : Average Percentage Cracking Efficiency of Nut

Frequency(Hz) Percentage Cracking Efficiency (%) Note

60 99.30 Testing 2

55 98.88 Testing 1

50 98.59 Current

45 97.48 Testing 3

40 94.75 Testing 4

The percentage cracking efficiency increased with increasing the speed of rotor.

The limitation of the inverter speed only 60Hz. Hence, the ripple mill can be allowed

to run at 60Hz to produce higher percentage of cracking efficiency.

45

4.4.2 Cracking Efficiency based on variable of Spacing between rotor and ripple plate:

The figure 4.12 shown the percentage cracking efficiency versus gap

between rotor and the ripple plate. The result in figure 4.12 is for average feed

rate of 9tan/hr and the rotor speed of 60hz. Five data were taken for each set

up experiment was run started from 0 inch as at present gap which resulted

the average cracking efficiency of 99.3% (Appendix 3). The average cracking

efficiency was 93.29% when the gap between ripple plate increased to 0.5inch.

The result shown a decreased in average cracking efficiency to 89.13% the gap

between rotor and ripple plate was adjusted to 1 inch (table 4.4).

Figure 4.12 : Percentage Cracking Efficiency(%) Versus The Gap of Ripple

plate

84

86

88

90

92

94

96

98

100

102

0 0.5 1

Percentage Cracking Efficiency(%) Versus Gap (Inch)

Gap (Inch)

Cra

ckin

g Ef

fici

ency

(%

)

46

Table 4.4 : Average Percentage Cracking Efficiency of Nut

Gap(Inch) Percentage Cracking Efficiency (%) Note

0.0 99.30 Testing 2

0.5 93.29 Testing 1

1.0 89.13 Current

It can be concluded that the gap of the rotor and the ripple plate has an effect on

the cracking efficiency. Its the gap increased, the percentage cracking efficiency

decreased. Hence, the present set up of the gap between rotor and ripple plate

resulted the appropriate percentage cracking efficiency.

47

CHAPTER 5

CONCLUSION

In conclusion, the objectives of this project are achieved:

1. The material of the rotor rod was identified as harden carbon steel of

between 3% to 8% carbon. Threatment could be done to increase the

strength of the rotor rod.

2. The suitable distance baffle plate was determined for use at the rotor of

ripple mill in order to increase the shelf life of the rod. To reduce the

bending of the rotor rod, the baffle plate can be increased from two to

three.

3. The speed of ripple mill and spacing between rotor and ripple plate after

the percentage cracking efficiency. By increasing the speed of the rotor

from 40Hz to 60Hz, the percentage cracking efficiency increased. When

the gap of the rotor and the ripple plate increased, the percentage cracking

efficiency decreased.

4. It suggested that, the optimum speed of the rotor is 60Hz and the number

of baffle plate is three.

48

References:

[1] http://lipidlibrary.aocs.org/processing/palmoil/index.htm

[2] http://www.palmoilextractionmachine.com/product/palm_oil_refinery_process/

palm-oil- mill-85.html

[3]

http://www.palmoilextractionmachine.com/product/palm_oil_refinery_process

/palm-oil- mill-85.html

[4] Ajewole, P. O. (2014). Experimental Determination of the Rotor Speed of a

Vertical Shaft Centrifugal Nut Cracking Machine, 2(5), 506–510.0

[5] Esua, O. J., Onwe, D. N., Etuk, V. E., & Okoko, J. U. (2015). Investigation

into the Energy Demand for Palm Nut Cracking Using the Static Impact

Method, 3(1), 7–14.

[6] Ndukwu, M. C., & Asoegwu, S. N. (2010). Functional performance of a

vertical-shaft centrifugal palm nut cracker, 56(2), 77–83.

[7] Ndukwu, M. C., & Asoegwu, S. N. (2011). A mathematical model for predicting

the cracking efficiency of vertical-shaft centrifugal palm nut cracker, 57(3), 110–

115.

49

Appendices

Appendix 1: 1. The horizontal strength of the nut kernel by Universal Testing

Machine(UTM):

50

2. The vertical strength of the nut kernel by using Universal Testing

Machine(UTM):

51

Appendix 2: Percentage of carbon in rod carbon steel:

Result 1:

EDAX TEAM EDS Page

s-3400 Author:

Creation: 2/27/2015

Sample Name: New Sample

Area 1

EDS1 kV: 15 Mag: 2005 Takeoff: 35.5 Live Time: 30 Amp Time: 6.4 Resolution: 125.5

Element Weight % Atomic

%

Net Int. Net Int. Error

C K 3.82 15.16 8.64 0.09

F K 1.63 4.09 24.93 0.1

MnK 0.89 0.77 5.8 0.46

FeK 92.33 78.9 448.55 0.01

CoK 1.34 1.08 5 0.63

52

Result 2:

EDAX TEAM EDS Page 1

s-3400 Author:

Creation: 2/27/2015

Sample Name: New Sample

Area 2

EDS1 kV: 15 Mag: 2001 Takeoff: 35.5 Live Time: 30 Amp Time: 6.4 Resolution: 125.5

Element Weight % Atomic

%

Net Int. Net Int. Error

C K 4.75 17.68 11.84 0.08

F K 3.9 9.18 66.77 0.05

FeK 89.83 71.98 474.82 0.01

CoK 1.53 1.16 6.23 0.45

53

Result 3:

EDAX TEAM EDS

s-3400 Author:

Creation: 2/27/2015

Sample Name: New Sample

Area 3

EDS1 kV: 15 Mag: 2000 Takeoff: 35.7 Live Time: 30 Amp Time: 6.4 Resolution: 125.5

Element Weight % Atomic

%

Net Int. Net Int. Error

C K 8.02 27.17 22.12 0.05

F K 4.12 8.82 73.18 0.04

FeK 86.66 63.17 491.19 0.01

CoK 1.21 0.83 5.28 0.64

54

Appendix 3: 1. Cracking Efficiency based on variable of frequncy(Hz):

(Fixed Variable : gap = 0 inch , throughput = 9ton/hr)

Frequency(Hz) Sample Cracking efficiency(%)

60 1 99.17

2 99.17

3 99.4

4 99.4

5 99.37

average 99.30%

55 1 98.47

2 98.81

3 99.64

4 98.86

5 98.6

average 98.88

50 1 97.87

2 97.66

3 99.38

4 98.73

5 99.33

average 98.59

45 1 97.47

2 96.96

3 97.22

4 97.84

5 97.89

average 97.48

40 1 94.75

2 94.5

3 95.75

4 93.44

5 95.3

average 94.75

55

2. Cracking Efficiency based on variable of Spacing between rotor and ripple

plate: (Fixed Variable : Speed = 60 hz , throughput = 9ton/hr)

Gap (Inch)

Sample Cracking efficiency(%)

0

1 99.17

2 99.17

3 99.4

4 99.4

5 99.37

average 99.30%

Gap(inch)

Sample Cracking efficiency(%)

0.5

1 93.3

2 94.25

3 93.56

4 92.84

5 92.49

average 93.29%

Gap(inch)

Sample Cracking efficiency(%)

1

1 85.34

2 89.84

3 90.76

4 88.94

5 90.76

average 89.13%