modification of a coconut oil extractor hassan, moshood abiola

MODIFICATION OF A
COCONUT OIL EXTRACTOR
SUBMITTED BY
HASSAN, MOSHOOD ABIOLA
MATRIC NO: 2006/0692
TO
DEPARTMENT OF AGRICULTURAL ENGINEERING
COLLEGE OF ENGINEERING
UNIVERSITY OF AGRICULTURE ABEOKUTA
OGUN STATE, NIGERIA
IN PARTIAL FULFILMENT OF THE
REQUIREMENT OF THE AWARD OF THE DEGREE OF
BACHELOR OF ENGINEERING
AUGUST, 2011
1

CERTIFICATION
We certify that this project work was carried out by HASSAN MOSHOOD ABIOLA, in the
Department of Agricultural Engineering, College of Engineering, University of Agriculture
Abeokuta, Ogun State.
........................................................ .............................................................
Supervisor
Head of Department
ENGR. DR. T.M.A OLAYANJU
ENGR. PROF. B.A. ADEWUNMI
(Associate Professor; MNSE, MNIAE, MNIFST)
(FNSE, FNIAE, MNIFST)
2

DEDICATION
This project is dedicated to the Almighty Allah who has seen me through for period of my course
and my late brother Mr. Adebowale Muideen Hassan. Though you have gone, but your virtues
live with us.
3

ACKNOWLEDGEMENT
In the name of Allah, the most beneficient, the most merciful.
My sincere gratitude goes to the Almighty Allah the Reckoner, the source of peace, the
Guardian of faith, the protector, the creator of heaven and earth, the most exalted, the selfsubsisting,
the first and last, the giver of live, the light of the heaven and earth and ever lasting
one, who has been seeing me through over the year.
My thanks go to my supervisor Engr. Dr. T.M.A. Olayanju who has help me through in
supervising, check thouroughly, for their constructive criticism, suggestions and advice. He
make a great difference in the success of this project.
Also thanks go to my Head of Department Engr. Prof. B.A. Adewunmi, all my lecturer,
Dr. Adewunmi, Engr. Aderinlewo, Engr. Sobowale, Dr. Dairo, Engr. Ola, Engr. Dada, Engr.
Adeosun, Prof. Ajayi, Prof. Ohu, for there support, effort and their contribution in my study
throughout my staying in this school may the Almighty Allah blessed you all (Amen).
My special thanks go to all members of Alhaji Hassan Shatoke family, my parent Alhaji
and Alhaja Hassan Shatoke may the Almighty Allah let you reap the ripe fruits of your, joy
(Amen), my brothers, Mr. Musiliu Hassan, Mr. Monsuru Hassan, Monsurat Hassan, Mrs.
Morufat Adeola, Mr. Saheed Adeola, Nureni Hassan and to all my cousin and all my friends.
I simply love you all. And may the Almighty Allah bless you all (Amen). Finally, I
surrender all glory to the Almighty Allah for his provison and inspiration bestowed upon me.
Thanks
4

ABSTRACT
A prototype of hydraulically operated coconut oil extractor was designed and fabricated.
The machine can be used for other oil-bearing seeds such as groundnut and palm kernel. The
machine is made up of a plunger, ram disc, expression chamber, and electric heater. The
extractor can process 10kg coconut per hour.
An efficiency of 15% was obtained from the coconut cake of 2.9kg (wet basis). While
for the dry basis 40% of oil was obtained from coconut cake of 2.5kg.
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TABLE OF CONTENT
TITLE PAGE.............................................................................................................................i
CERTIFICATION.....................................................................................................................ii
DEDICATION..........................................................................................................................iii
ACKNOWLEDGEMENT........................................................................................................iv
ABSTRACT..............................................................................................................................v
TABLE OC CONTENTS.........................................................................................................vi
CHAPTER ONE
1.0 Introduction....................................................................................................................1
1.1 Background.....................................................................................................................1-3
1.2 Objectives of Work..........................................................................................................3
1.3 Justification......................................................................................................................3
CHAPTER TWO
2.0 Literature Review............................................................................................................4
2.1 General............................................................................................................................4-5
2.2 Coconut Oil....................................................................................................................5-6
2.3 Coconut Oil Characteristics and Uses...........................................................................6-8
2.4 Coconut Oil Processing Technology.............................................................................8-16
CHAPTER THREE
3.0 Design Features and Analyses......................................................................................17
3.1 The Improved Coconut Oil Extractor...........................................................................17
3.2 Design Features.............................................................................................................17
3.3 Design Conception........................................................................................................17
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3.4 Design Assumption......................................................................................................17-18
3.5 Design Analysis...........................................................................................................18-24
CHAPTER FOUR
4.0 The Extractor: Description and Modification Details.................................................25
4.1 Description of An Existing Extractor..........................................................................25
4.2 Description/Modification Procedures.........................................................................25-35
4.3 Assembly of the Machine...........................................................................................36-37
4.4 Machine Maintenance.................................................................................................38
4.5 Cost Estimated on the Developed Extractor..............................................................38-39
CHAPTER FIVE
5.0 Machine Testing and Performance.............................................................................40
5.1 Testing and Performance............................................................................................40-46
5.2 Discussion...................................................................................................................46
CHAPTER SIX
6.0 Conclusion and Recommandations.............................................................................47
6.1 Conclusion..................................................................................................................47
6.2 Recommandations........................................................................................................47
REFERENCE.......................................................................................................................48-49
APPENDIX...........................................................................................................................50-57
T
7

CHAPTER ONE
1.0 INTRODUCTION
1.1 Background Information
The coconut (Cocos nucifera) is a member of the family Arecaceae (palm family) and is
one of the nature’s gifts to mankind (William, 1997).
It is the only accepted species in the genus Cocos, and is a large palm, growing up to
30m tall, with pinnate leaves 4–6 m long, and pinnae 60–90 cm long; old leaves break away
cleanly, leaving the trunk smooth and the term coconut can refer to the entire coconut palm, the
seed, or the fruit, which is not a botanical nut (World Wildlife Fund, 2010).
Coconut has been part of peoples’ diet and livelihoods in the tropical countries of Asia,
the Pacific, South and Central America and Africa for thousands of years. In these areas, native
meals are cooked with either coconut milk or coconut oil. The coconut palm is grown throughout
the tropics for decoration, as well as for its many culinary and non-culinary uses; virtually every
part of the coconut palm can be utilized by humans in some manner. However, the extent of
cultivation in the tropics is threatening a number of habitats such as mangroves; an example of
such damage to an ecoregion is in the Petenes mangroves of the Yucatan (Foale,2003).
Coconut palms are believed to be largely cross-pollinated, although some dwarf varieties
are self-pollinating. The meat of the coconut is the edible endosperm, located on the inner
surface of the shell. Inside the endosperm layer, coconuts contain an edible clear liquid that is
sweet, salty, or both (Fife, 2005).
Although coconut meat contains less fat than many oilseeds and nuts such as almonds, it
is noted for its high amount of medium-chain saturated fat and about 90% of the fat found in
coconut meat is saturated, a proportion exceeding that of foods such as lard, butter, and tallow.
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There has been some debate as to whether or not the saturated fat in coconuts is less unhealthy
than other forms of saturated fat (see coconut oil). Like most nut meats, coconut meat contains
less sugar and more protein than popular fruits such as bananas, apples and oranges. It is
relatively high in minerals such as iron, phosphorus and zinc (Nutritiondata.com).
Coconut oil is extracted from the kernel or meat of matured coconut harvested from the
coconut palm (Cocos nucifera). Throughout the tropical world it has provided the primary source
of fat in the diets of millions of people for generations. It has various applications in food,
medicine, and industry. Coconut oil is very heat stable so it makes an excellent cooking and
frying oil. It has a smoke point of about 360°F (180°C). Because of its stability it is slow to
oxidize and thus resistant to rancidity, lasting up to two years due to high saturated fat content.
In the wet process, coconut milk is made first and then the oil is extracted from the milk (Fife
2005).
Coconut kernel is shredded and mixed with water. Then it is pressed and the oil is
extracted. The resulting oil/water mixture is left to sit and it separates into two layers, watery on
the bottom, creamy on top. The thicker cream is decanted off the top and the original method of
separation involved heating or fermenting the milk to separate the oil. This traditional method
made a very unstable oil with a short shelf life meant for quick daily use. Due to its miscible
nature coconut oil is cannot be separated naturally from the cream (Ohler,1984).
All high volume modern methods incorporate heating, fermentation, and or centrifugal
force to separate the oil from the water. Some minor heating is generally done afterwards (often
in a low temperature vacuum chamber) to drive off excess moisture and produce a more purified
product and to extend shelf life. Proper harvesting of the coconut (the age of a coconut can be 2
to 20 months when picked; the time of harvesting makes a significant difference in the effiacy of
9

the oil making process) and the use of a centrifuge process make the best final extracted product
(Woodruff,1970).
1.2 Objective of the work
The main objective of this project is to design and fabricate a coconut oil extractor that
will be suitable for cottage scale oil production.
The specific objectives are to:
• To modify the existing design of a coconut oil extractor.
• Evaluate the performance of the extractor.
1.3 Justification
Traditionally, virgin coconut oil is produced by fermentation method, where coconut
milk expelled from freshly harvested coconuts is fermented for 24-36 hr, and during this period,
the oil phase gets separated from aqueous phase. Further, the resulting wet oil is slightly heated
for a short time to remove the moisture and finally filtered. The main disadvantages of this
process are low oil recovery and fermented odour, which masks the characteristic coconut
flavor of the oil.
The construction of a coconut oil extractor will help in alleviating the suffering experienced by
the use of traditional oil extraction method thereby improving the quality and quantity obtained
and this will also bring about the production of high grade oil
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CHAPTER TWO
2.0 LITERATURE REVIEW
2.1 General
Philippines, Indonesia, India, Sri Lanka, Mexico, West Malaysia, and Papua & New
Guinea are the 7 countries which produce major quantities of coconut in the world. Coconut is
available in two forms viz., wet and dry materials commonly known as wet coconut and dry
coconut or copra. The oil can be extracted from both these raw materials. However, in India and
Srilanka, it is a general practice to use only copra for oil extraction and the oil is used for food
and cosmetic purposes. In Phillippines, the oil is extracted from wet coconut also and is known
as virgin coconut oil. In some countries solvent extraction of the dry coconut followed by
refining, bleaching and deodorization is carried out to get the refined bleached and deodorized
coconut oil. The technology for the production of coconut oil through expellers is well developed
and many medium scale industries in India produce oil by this method. However, some small
scale industries produce the oil by processing fresh coconut also using local expeller press.
Problems of sediments and rancidity persist in these oils (Cornelius, 1973).
In the Cook Islands in the South Pacific, particularly Rarotonga Island, slices of fresh,
mature coconut kernel are served with fruits every after meal. In India, the use of coconut for
food and its applications in the Ayurvedic medicine, were documented in Sanskrit 4000 years
ago (Kabara, 2000).
Records show that in the United States, coconut oil was one of the major sources of
dietary fats, aside from dairy and animal fats, prior to the advent of the American edible oil
(soybean and corn) industry in the mid 1940s (Dayrit, 2005). Dayrit has reviewed the long
history of usage and the diverse studies done to characterise and define the composition of the
11

various components of the coconut tree, its fruit and the related products derived from it,
established the coconut’s uniqueness and superiority among agricultural crops and every part of
the coconut tree and its fruit can be either consumed by humans or animals or converted into
other valuable products. If properly utilised, the coconut has the highest economic value among
the palm family. This is why the coconut is normally referred to as the Tree of Life, Man’s Most
Useful Tree, King of the Tropical Flora, Tree of Abundance.
2.2 Coconut Oil
Oil obtained from the fresh, mature kernel (meat) of the coconut by mechanical or natural
means, with or without the use of heat, without undergoing chemical refining, bleaching or dedourising,
and which does not lead to the alteration of the nature of the oil. Virgin coconut oil is
suitable for human consumption without the need for further processing (Fife, 2005).
Virgin coconut oil consists mainly of medium-chain triglycerides, which are resistant to
peroxidation. The saturated fatty acids in virgin coconut oil are distinct from animal fats, the
latter constisting mainly of long-chain saturated fatty acids (Furman).
The Philippine National Standard for Virgin Coconut Oil (PNS/BAFPS 22:2004/ ICS
67.2000.10) officially defines Virgin Coconut Oil as: the purest form of coconut oil, essentially
water clear or colourless. It contains natural Vitamin E and has not undergone any hydrolytic and
atmospheric oxidation asdemonstrated by its very low, free fatty acid (FFA) content (even
without refining) and low peroxide value. It has a fresh coconut aroma that can be mild to intense
depending on the oil extraction process used. Virgin coconut oil differs greatly from traditionally
produced, copraderived coconut oil, which must undergo chemical refining, bleaching and deodourisation
processes to make it suitable for human consumption. RBD (Refined, Bleached and
12

Deodourised) coconut oil made from copra, is yellow in colour, odourless, tasteless and does not
contain natural Vitamin E, since this is removed when the oil is subjected to high temperature
and various chemical processes.
2.3 Coconut Oil Characteristics and Uses
The degree of saturation and length of the carbon chain of the fatty acids comprising a
particular fat or oil determines its properties, corresponding uses and its effects on human health.
The more saturated the fat and the longer the chain, the harder the fat and the higher the melting
point (Fife, 2001).
Coconut oil is unique amid fats and oils, as it contains the highest percentage of mediumchain
fatty acids (MCFA) with a carbon-chain length of 8 to 12 carbon atoms. VCO behaves and
metabolises differently in the human body to other saturated and unsaturated fats or oils. MCFA
in coconut oil is about 64%, with lauric fatty acid (C12) as the highest ranging from 47 to 53%
depending on the coconut variety (Babayan, 1968).
Babayan has reviewed that the most significant physical property of coconut oil is that
unlike most fats, it does not exhibit gradual softening with increasing temperature, but passes
rather abruptly from a brittle solid to a liquid within a narrow temperature range. In this respect,
it resembles cocoa butter (Spectrum of Coconut Products, Philippine Coconut Authority,
undated). Coconut oil is liquid at about 27°C or higher and solidifies at about 22°C when it has
the consistency of butter in temperate countries.
Copra-derived coconut oil has been produced and used commercially for almost a century
as such, its use for edible and inedible applications has already been well established (Banzon,
1990). For edible purposes, coconut oil is generally used as (Banzon, 1990):
13

• A frying and cooking oil because of its excellent resistance to rancidity development.
• It is also used as a substitute for expensive butter fat in filled milk, filled cheese and ice
cream making these products cheaper without changing their palatability.
• When hydrogenated, coconut oil is used as margarine, shortening and baking fat.
Other edible applications of coconut oil are (Banzon, 1990):
• As a source of fat in infant formulas and baby foods because of its easy digestibility and
absorbability;
• As a spray oil for crackers, cookies and cereals to enhance flavour, increase shelf-life and
impart a glossy appearance;
• As an ingredient in confectionaries such as candy bars, toffee, caramels, etc.
The Spectrum of Coconut Products states that in food preparations and in diet, coconut
oil performs the following functions (Enig, 2001).
• It serves as an important source of energy in the diet.
• It supplies specific nutritional requirements.
• It provides a lubricating action in dressings or leavening effect in baked items.
• It acts as carrier and protective agent for fat-soluble vitamins.
• It enhances the flavour of food.
The major inedible use of coconut oil is as a raw material in the manufacture of laundry
and bath soaps; as coconut chemicals for production of biodegradable detergents, shampoos,
shower gels and other cleaning agents; for cosmetics and toiletries; for foam boosting of noncoconut
oil based soaps; for the production of synthetic resins and plasticisers for plastic etc
(Pattra, 2004).
14

In Thailand, coconut oil is mixed with 10 to 20% kerosene, settled to remove free fats,
filtered and used as a diesel fuel substitute. In Vanuatu and other Pacific Islands, coconut oil
isused directly as a substitute for diesel (Bawalan, 2005).
The current emerging major uses of virgin coconut oil (Fife,2004) are as:
• A hair and skin conditioner;
• An oil base for various cosmetic and skin care products;
• A carrier oil for aromatherapy and massage oils;
• A nutraceutical and functional food.
2.4 Coconut Oil Processing Technology and Equipment
Virgin coconut oil can be produced directly from the fresh comminuted (grated, chopped,
granulated) coconut meat, or from coconut milk, or from coconut milk residue. The choice of the
technology to be adopted, depends to a great extent on the scale of operation, the degree of
mechanisation desired, the amount of investment available and the demands of the prospective
buyer. The scale of operation to be implemented is significantly dependant on the available
coconut supply base (Weiss, 1999).
Oil can be extracted manually by pressing softer oilseeds and nuts, such as roundnuts and
shea nuts, whereas harder, more fibrous materials such as copra and sunflower seed can be
processed using Ghanis. Pulped or ground material is loaded into a manual or hydraulic press to
squeeze out the oil-water emulsion. This is more efficient at removing oil than traditional hand
squeezing, allowing higher production rates. Fresh coconut meat is removed from the shell using
a manual or (Weiss, 1999) motorised grater (Fig. 2.1).
15

Fig. 2.1: A manual coconut grater
Adapted from UNIFEM (1986)
16

UNIFEM (1987) classified expression devices in three categories viz: plate presses,
ghanis and expellers. Oil plate presses are of two types: screw press and hydraulic press.
Presses have a number of different designs, commonly based on a bridge press. In all
types, a batch of raw material is placed in a heavy-duty perforated metal ‘cage’ and pressed by
the movement of a plunger. The amount of material in the cage varies from 5-30 kg with an
average of 20 kg. Layer plates can be used in larger cages to provide a constant pressure through
the bulk of material and speed up removal of oil. The pressure should be increased slowly to
allow time for the oil to escape. Screw types are more reliable than hydraulic types but are
slower and produce less pressure. Except where a lorry jack is used (Fig. 2.2), hydraulic types
are more expensive, need more maintenance, and risk contaminating oil with poisonous
hydraulic fluid (Potts, 1993).
In a screw press, steamed beniseed is pressed slowly and with pressure by a plunger force
down by screw and into a cylinder with large number of small holes (Plate 2.1). Capacities of
screw presses depend upon the size of the cage, an average being about 1.5 kg per batch
(Potts, 1993). Potts also reviewed that in an hydraulic press, pressure is exerted by an hydraulic
device such as a lorry jack. It requires a heavy - rigid framed structure . Hydraulic presses
generate greater pressure than plate presses. However, the hydraulic fluid should be prevented
from coming in contact with the oilseed.
Ram press is a long pivoted lever moves a piston backwards and forwards inside a
cylindrical cage constructed from metal bars spaced to allow the passage of oil. At one end of
the piston's stroke, it opens an entry port from the seed hopper so that seed enters the press
cage(plate 2.1).When the piston is moved forward, the entry port is closed and the oilseed is
compressed in the cage. As a result, oil is expelled from the oilseed and emerges through the
17

Fig. 2.2: Oil press with a hydraulic jack
Adapted from Kickstart (1993)
18

Pla
te 2.1: Ram press
Adapted from kickstart (1993)
19

gaps in the cage, compressed seed is pushed out through a circular gap at the end of the cage.
The width of this gap, which can be varied using an adjustable pressure cone, controls the
operating pressure of the press. The design of the press is such that it can achieve operating
pressures in excess of those obtained in most manually operated cage presses and as high as
those in small expellers. The ram press has a low seed throughput but has the advantage of
continuous operation. The ram press was developed in Tanzania specifically for processing a
thin shelled high oil content variety of sunflower seed. The technique can also be used for copra,
groundnuts and sesame (Weiss, 1999).
Ghanis are widely used in Asia but less so in other areas. A heavy wooden or metal pestle
is driven inside a large metal or wooden mortar (Fig. 2.3a). The batch of raw material is ground
and pressed and the oil drains out. They have relatively high capital and maintenance costs and
need skilled operators to achieve high oil yields. The ghani (mechanised extraction) consists of a
large mortar and pestle, the mortar being fixed in the ground and the pestle being moved within
the mortar by animal traction (donkey or mule) or (more commonly) a motor. Oilseeds are
placed in the mortar and the pestle grinds the material to remove the oil. The oil runs out of a
hole in the bottom of the mortar and the cake is scooped out by hand. This method is slow and
requires two animals, replacing the tired one with another after about 3-4 hours of work.
Motorised ghanis (Fig. 2.3b) are faster than manual or animal types but are more expensive and
their higher capital and operating costs will require a larger scale of production for profitability
(Ghani, 1993).
20

(a)
(b)
Fig. 2.3 (a) Animal powered extraction (b) Motorise extraction
Adapted from FAO (1993)
21

An expeller consist of a helical thread (worm assembly) which revolves concentrically
within pertorated cylinder (the cage or barrel). The barrel is usually formed by a series of axiallyplaced
lining bars contained within a robust frame. Heated oilseeds enter one end of the barrel
through the feed inlet and are conveyed by the rotating worm assembly to the discharge end.
With any power-driven equipment, it is important to consider how the equipment will be
repaired as it becomes worn (Plate 2.2). Local refurbishment is normally cheaper than importing
spare parts (Fellow and Hampton, 2002).
22

Plate 2.2: Rosedowns Maxoil press.
(Fellow and Hampton, 2002).
23

CHAPTER THREE
3.0 DESIGN FEATURES AND ANALYSES
3.1 The improved coconut oil extractor
The coconut oil extractors are capital intensive and of complex design and construction.
Although these are of high production capacities and are appropriate for the producer on small
scale with limited supply of coconut.
A functional, manually hydraulic operated oil extractor containing a finely perforated
cylinder which carries an internal pressure plate that can be moved upwards and downwards
within the cylinder was modified.
3.2 Design features
The following points are considered:
i. The design should be simple and the construction should be at minimum cost.
ii.
Power requirement to operate the equipment should be minimal. This is to be
achieved by providing means for efficient power utilization.
iii.
The component parts should be easily replaceable in case of any damage.
3.3 Design conception
Base on the above, the following specifications were conceived:
• The extractor is a cage/screw press type. It is to consist plunger (shaft) with an expression
chamber. The plunger (constitute hub and shaft) is to be bolted at the top of the frame.
• The input capacity of the extractor is to be 10kg per batch.
3.4 Design assumption
For simplicity of design, the following assumptions are made;
24

• A grown up man of average power of 0.05kw can conveniently apply a hand force of
210N at a speed of 60rpm for a time duration depending on the material being
compressed (Sanders and McCormick, 1987).
• In one revolution of the screw shaft, discharge of coconut oil is advanc e by one pitch of
the hydraulic pump.
3.5 Design analyses
The coconut oil extractor made up of the following components:
• Hydraulic pump
• Plunger/ram (constitute hub and shaft)
• Ram disc
• Expressing chamber
• Electric heater
The design of each components is described as follows:
3.5.1 Hydraulic pump
3.5.2 Power requirement
A
F
X
At point end A of the plumger (shaft), a force F is applied at distance x from the axis of
the ram disc attached to the bottom of expression chamber where the coconut materials being
compressed. The turning moment transmitted by the shaft is, T = Fx.
25

From section 3.4, a force of 210N can be applied by a man at a speed of 60rpm and at a distance
0.2m from the axis and tangential to the shaft.
i.e T = 210 x 0.2
= 42Nm ....................................................................(3.1)
The pressure required required from the pump to express the coconut oil from the
coconut base on the maximum applicable load is given as:
Presssure, P = F / A .....................................................................3.2
P = pressure required from the pump
F = 210N
A = πd 2 / 4
where d = diameter of the expression chamber which is 240mm
A = 3.142 x 0.24 2 / 4
=0.0452m 2
P= 210 / 0.0452 ............................................................................................................3.3
P= 4.6KN/ m 2
Therefore, the pressure required from the pump to extract oil from the coconut cake is 4.6KN/m 2
The power requirement to pump the hydraulic through the handle and eventually express
the coconut oil from the coconut based on the maximum applicable load is given as;
Px = 2πNT...................................................................................................................3.4
Where;
26

N = Speed of rotation = 60rpm (section 3.4)
T = Torque on the shaft = 105Nm
:- Px = 2 x 3.142 x 60 / 60 x 42
= 263.9watts
= 0.263Kw ................................................................................................3.5
3.5.3. Design of Shaft
The extractor shaft is to be designed on the basis of torsional load only. This involve
analyses based on strength and rigidity.
3.5.4. Strength criterion
The required diameter for a solid shaft having torsional load only is obtained from ASME
code equation (Hall, et al., 1980) as follow:
D 3 = 16T / S ................................................................................3.6
Where,
S = allowable stress = 55Mpa (for shaft without keyway)
T = Torque
D 3 = 16 x 42 / 55x10
6
= 1.22 x10 -5
D = (1.22 x10 -5 ) 1/3
D = 0.023m
:- D = 23mm (says 25mm)................................................................................3.7
27

3.5.5 Torsional deflection
The design of shaft for torsional rigidity is based on the permissible angle of twist. The
permissible angle of twist for steel is 3deg/m (Surrender, 1979).
For limiting the twisting to the given limit, the angle of twist (radian)
θ = TL / GJ .......................................................................................................3.8
where,
T = Torque (Nm) = 42Nm (3.5.2.1)
L = Length of shaft (m) = 0.6m (assumed)
J = Polar moment of inertia for the shaft section = πD 4 / 32 (for circular shaft)
G = Modulus of rigidity of the shaft material = 80GN/m 2
From the above equation, the polar moment of inertial will be equal to:
J = TL / Gθ
πD 4 / 32 = 42 x 0.6 x 180 / 80x10
9
x 3 = 1.9x10 -8
D 4
= 32 x1.9x10-8 / π
D 4 = 1.92 x 10 -8
D = 0.021m = 21mm.......................................................................................3.9
For both stress and the twist to be within permissible limit, a steel shaft (plunger) of 25mm
diameter is choosen.
3.5.5 Weight of Shaft
28

The weight of the shaft are expressed below:
W s = S 8 V 8 g ................................................................................................................3.10
S 8 = density of shaft = 7800kg/m 3 for steel
V 8 = Volume of shaft = πD 2 L/ 4
W s = π (0.025) 2 x 0.6/ 4
= 2.9 x10 -4
g = acceleration due to gravity = 9.81m/s 2
W s = 7800 x2.9 x10 -4 x 9.91
= 22.4N ...............................................................................................................3.10
3.5.6. Ram disc
The ram disc (working like a piston) is expected to compress the material fed into the
expressing chamber as a result of the axial pressure form the hydraulic pump, the material being
extracted at the same time exert a pressure equal but opposite on the point face.
This force and pressure consideratioins necessitate the choice of a rigid and strong
material for the point. A stainless steel of 240mm in diameter and 40mm long is choosen.
The weight of the piston,
W p = S p V p g .......................................................................................................3.11
S p = density of ram disc material = 7800kg/m 3
V p = volume of piston = π (0.24)2 x 0.04 / 4
= 1.81 x 10 -3 m 3
29

Therefore, W p = 7800 x 1.81 x 10 -3 x 9.81
= 137.7N .........................................................................................3.12
3.5.7 The expressing chamber
The chamber is to to be designed on the basis of internal pressure only. If the housing is
treated as a thin walled cylinder, then using the standard stress (stiffness) analysis applied to thin
walled pressure vessels (Surrender, 1979), the maximum shear stress,
σ = Pr/ 4t .........................................................................................3.13
where;
σ = The maximum stress the cylinder will be subjected to at failure by yield. For steel, the
ultimate or yield sstress is 140MN/m 2 the stress using a factor of safety of 2 is 70MN/m 2 .
P = Internal pressure which equal to 35MN/ m 2
r = internal radius of the cylinder = 0.120m
t = thickness of the cylinder
70 x10 6 = 35x 10 6 x 0.120/ 4t
t = 35x 10 6 x 0.120
/ 70 x10
6
x4
= 0.15m (15mm) .............................................................................3.14
From the design, expression chamber of 15mm thickness is require to widstand the pressure
which will be too costly for stainless steel and therefore stainless steel cylinder of 5mm was
selected and mild steel plate of 10mm thinkness were cut and place at the bottom of expression
30

chamber (i.e. expression chamber sit on the mild steel plate which resist the pressure as the
materials being compressed).
3.5.8. Torsional Springs/Returning spring
Helical spring made up of circular diameter was selected based on the following equation.
T = W ( D / 2 ) { Khurmi, Guputa (1979)} ...........................................3.15
Where T = Torque (N.m)
D = Mean Diameter of the spring coil
W = Axial load on the spring
From the design T = 42Nm, W= 210N
D = 42x 2 /210
= 0.4m
31

CHAPTER FOUR
4.0 THE EXTRACTOR: DESCRIPTION AND MODIFICATION DETAILS
4.1 Features of An Existing Extractor
The existing extractor consists of four integral parts namely: the expression chamber, the
plunger, the compression plate, and the frame. The major problem facing the existing extractor
are listed below.
• Instability of plunger
• Leakages of hydraulic oil
• Light thinkness of expressing chamber which can cause damages of the chamber
during compression.
• Irregularity in shape of compression plate or ram press
• No electic heater was supplied with design
4.2 Description/Modification Procedure
A prototype hand operated hydraulic of an existing (Plate 4.1a) oil extractor was
modified (Plate 4.1b) using available materials. Appendix 3 shows the orthographic and
isometric views of the extractor.
The modified extractor consist of five integral parts namely: The frame, The power
transmission shaft or plunger, expression chamber, compression plate (ram press) and electric
heater devices. The procedure of these components is described below to show the sequence of
operation performed on each.
32

(a)
(b)
Plate 4.1(a) An existing coconut oil extractor (b) Modified coconut oil extractor
33

4.2.1 The Frame
The frame was fabricated with 4inches channel (50mm x 100mm x 50mm in dimension).
The frame is rectangular in shape having length and breadth of 1036mm and 600mm
respectively. Most of the joints were fastened together by bolt and nut and other joint by electric
arc welding.
4.2.2 The Power Transmission Shaft
From the design, plunger of 25mm shaft was selected which used to transmitted force
needed to compressed coconut cake from the hydraulic pump. The ends of the plunger was hang
at the top of the frame and fastened with bolt and nut (25mm), due to instablity of the plunger of
an existing oil extractor (Plate 4.2a), flat bar of 8mm thickness was fabricated and fastened to the
upper end of the plunger/ram by 10mm bolt and nut, finally fastened to the frame (Plate 4.2.b)
34

(a)
(b)
Plate 4.2(a) An existing coconut oil extractor (b) Modified coconut oil extractor
35

4.2.3 The Expression Chamber
The expression chamber comprises of two cylinder (This expression chamber was
modified (Plate 4.4) by reducing the size of the existing one), the first cylinder of existing oil
extractor (Plate 4.3) was fabricated with perforated materials (mesh) made of 240mm in
diameter, 300mm long and 2mm thick which now reduced to 178mm long having the same
diameter and thickness. The second expression chamber of existing oil extractor are non
perforated cylinder with 260mm in diameter, 300mm long and 3mm thick which also reduced to
165mm long having the same diameter and thickness. Gate valve ( 1 / 2 inches) was welded to the
bottom end of the second expression chamber (non perforated cylinder). This gate valve (which
can be opened or closed) function as the outlet for collecting the coconut oil at the end of each
extraction process.
36

D
Plate 4.3: An Existing Coconut Oil Extractor
D = expression chamber
37

D
Plate 4.4: Modified Coconut Oil Extractor
D = expression chamber
38

4.2.4 Compression plate/Ram plate
The compression plate of the existing extractor (Plate 4.5a) was not perfectly sphere (i.e.
irregular shape) which will caused escaping of coconut cake during compression which will
reduced the efficiency of the extractor. Due to this, compression/ram plate was redesign and
fabricated. Stainless steel of 8mm thickness and 240mm diameter used for the fabrication of the
compression plate or ram disc (Plate 4.5b) and this was achieved by cutting 240mm diameter
from materials using cutting disc. Stainless pipe of 8mm thickness and 30mm long was weld at
the centre of the compression plate which aids easy attachment to the plunger by 10mm by
25mm bolt and nut through the hole drilled on the pipe and shaft(plunger).
39

B
B = Compression/ ram plate
(a)
B
(b)
Plate 4.5(a) An existing coconut oil extractor (b) Modified coconut oil extractor
40

4.2.5 Electric heater
The existing oil extractor have no electric heater therefore, electric heater (Plate 4.6) of
1500watts capacity was attached to the modified oil extractor having thermostat for controlling
temperature needed for the extraction of the coconut oil. Electric heater space was created below
the compression stand (expression chamber sit on this stand) and the compression stands used in
wisthand pressure from the hydraulic pump.
41

Electric heater
Plate 4.6: Electric heater
42

4.3 Assembly of the Machine
The following procedure should followed in order to assemble the machine (Plate 4.6):
• Bolt the plunger at the top of the frame with 20mm bolt
• Attached the ram press/disc to the plunger ends by fastened it with 20mm bolt and nut
• Attached the returning spring to the hangs provided on the ram disc and the frame.
• Set the perforated cylinder into the cylinder and set it on the compression stand.
• Put the electric heated into it space provided under the compression stand.
43

Plate 4.7: Assembly of the Extractor
44

4.4 Machine Maintenance
• The major maintenance of oil extrator required thorough cleaning of the expression
chamber, compression/ram disc at the end of each day work.
• When the machine is no more compressing as before, check and refilled the oil in the
hydraulic pump.
4.5 Cost Estimation of the Developed Extractor
The cost of construction of the coconut oil extractor was computed by considering the
individual component parts, and the expenses due to machining, welding and painting operation.
The cost are shown in the table 4.5 below:
45

Table 4.5: Bill of Materials for the Construction of the Coconut Oil Extractor
QTY DESCRIPTION RATE (N) AMOUNT (N)
1 Hydrualic ram 12,000 12,000
1 50x50x50 (4inch)U Channel 7,200 7,200
1 Perforated cylinder (240mm in diameter) 6,200 6,200
1 Cylinder (260mm in diameter) 6,100 6,100
1 50x50 (4inch) Angle iron 3,000 3,000
1 Electric heater with thermostart 5,500 5,500
1 Gate valve ( 1 / 2 Inch) 400 400
2 Torsional Spring 500 500
12 20mm bolt and nut 30 360
12 16mm bolt and nut 20 240
½ Mild Steel plate (3mm thick) 3,000 3,000
12 12mm bolt and nut 20 240
1 Packet of stainless electrode (Gauge 12) 4,500 4,500
Painting 2,500 2,500
20ft 4inch Angle iron 2,200 2,200
Transportation 3,000 3,000
TOTAL 54,000
46

CHAPTER FIVE
5.0 MACHINE TESTING AND PERFORMANCE
5.1 Testing and Performance
Coconut nut were obtained from the Kuto market in Abeokuta. These coconuts were
weighed. An uncracked coconut weighs about 1.4kg. Since the coconuts were of different sizes,
their weight varies between 0.9 - 1.4kg and grated manually. The testing were carried out for
both wet and copra coconut and the colour of the sample was notice at different temperature as
shown in fig. 5.1 and fig 5.2 below until golden colour was observed.
For wet basis, the uncracked coconut was weighed to be 3.4kg and after cracked (splitted)
and grated it weighed 2.9kg. The grated coconut meat was then compressed in the expression
chamber and heat was applied for the extraction of the coconut oil.
The following procedure was carried out during the testing of the machine for dry
coconut meat (copra):
• Fully matured nuts (Plate 5.1) was selected and weighed.
• It was split (Plate 5.2) and grated (Plate 5.3, Plate 5.4) manually and weighed to be 8kg
• Grated coconut meat was heated to a moisture content of 10 – 12% at a temperature of
70– 75°C (Anzaldo, F.E. et al, 1985) by using an indirect type of hot air dryer (copra
weigh 2.5kg).
• Oil extraction was extracted by using hydraulic operated coconut oil extractor (plate
5.5).
• Oil extraction was done when the moisture content of the material is relatively high, oil
is then heated by applying heat through the electric heater to ensure that all residual
moisture is removed to prolong the shelf-life of the coconut oil.
47

• The oil is left for a maximum of 6 hours to allow sufficient time for the trapped foots to
settle (Plate 5.6).
• Filtration of the oil is done using a three-layered filter cloth bag.
• The extracted oil was then package and stored.
FRESH DE-HUSKED NUT
SPLITING
GRATING
DRYING (10to 12 Moisture content)
PRESSING
OIL DRYING
FILTRATION
Chart showing the extraction process
48

Plate 5.1 Plate 5.2
Plate 5.3 Plate 5.4
Plate 5.5
49

Plate 5.6
50

5.1.1 Result obtained from the wet basis
Wet coconut weigh 2.9kg
Mixture of coconut milk and oil after extraction= 1.5kg
Table 5.1
Showing the result of the test for wet basis
WEIGHT TEMP. COLOUR WEIGHT OF WEIGHT OF QTY OF OIL
OF ( 0 C) OBSERVED COCONUT CAKE MIXTURE OF OBTAINED
CAKE DURING LEFT AFTER AND OIL BEFORE AFTER
EXTRACTION EXTRACTION FILTRATION FILTRATION
(Kg) (Kg) (Kg) (Kg)
2.9 25-60 White (milky solution) 1.28 1.6 0.04
2.9 61-100 White (milky solution) 1.37 1.5 0.09
2.9 101-114 White and Golden 1.27 1.6 0.1
2.9 115 Golden 1.35 1.5 0.4
From the table above it show that hightest percentage of oil was obtained at 115 0 C which
is 0.4 Kg (it was extracted for 25min) and above this tempetrature the coconut cake burnt and no
oil was obtained. The table above also show that the coconut oil will be best extracted at 115 0 C
for wet basis. The oil was obtained after settling of misture of cococonut milk and oil for about
an hours and filtrated, 0.8kg of coconut oil was obtained.
Efficiency of extraction obtained during the wet basis
Efficiency = weight of the oil obtained
Weight of the wet coconut
= 0.4 x 100
2.9
51

= 15%
5.1.2 Result obtained from the copra (Dry basis)
Wet cocotnut weigh = 8.5kg
After drying (copra) = 2kg
Mixture of coconut milk and oil = 1.5kg
Oil obtained after settling and filtration =0.8kg
Table 5.2
Showing the result of the test for dry basis (copra)
WEIGHT TEMP. COLOUR WEIGHT OF WEIGHT OF QTY OF OIL
OF ( 0 C) OBSERVED COCONUT CAKE MIXTURE OF OBTAINED
CAKE DURING LEFT AFTER AND OIL BEFORE AFTER
EXTRACTION EXTRACTION FILTRATION FILTRATION
(Kg) (Kg) (Kg) (Kg)
2 25-40 White (milky solution) 1.09 0.9 0.06
2 41-54 White (milky solution) 1.08 0.9 0.1
2 55-64 White and Golden 1.16 0.8 0.3
2 65-75 Golden 0.95 1.0 0.8
From the table above it show that hightest percentage of oil was obtained at 65-75 0 C which is
0.8 Kg (it was extracted for 20min) and above this tempetrature the coconut cake burnt and no
oil was obtained. The table above also show that the coconut oil will be best extracted at 65-75 0 C
for dry basis.
The oil was obtained after settling of misture of cococonut milk and oil for about an hours and
filtrated, 0.8kg of coconut oil was obtained.
Efficiency of extraction obtained during the wet basis
52

Efficiency = weight of the oil obtained
Weight of the wet coconut
Efficiency = 0.8 x 100
= 40%
2
5.2 DISCUSSION
An efficiency of 15% was obtained from the coconut cake of 2.9kg (wet basis) while for the dry
basis, 40% of oil was obtained from coconut cake of 2.5kg.
Therefore, it show that the extractor can perform better when the coconut meat is dry in
an oven to certain moisture content (10-12% moisture content) before extraction.
53

CHAPTER SIX
6.0 CONCLUSION AND RECOMMENDATIONS
6.1 CONCLUSION
The following conclusions can be drawn based on the test carried out in the modiffication of
design and fabrication.
1. Properly grated coconut will be extracted easily.
2. High quantity and quality of oil was extracted with the uses of this extractor.
3. It reduces stress undergone during the traditional method
4. The extractor can be developed for industrial used.
6.2 RECOMMENDATION
In order to achieve a better operation and more efficient oil extraction, the following
recommendations are made.
• Powering of the machine by using electric motor should be looked into, so as to increase
the efficiency of the machine.
• All equipment, where fresh coconut meat is being handled/processed, must be cleaned
after every four hours of use. Equipment must not be left un-cleaned at the end of a
production day. Cleaned equipment should be free of grease and adhering product
particles, detergent residue, brush bristles, etc.
• Grating machine should be look into in order to make a grating process faster.
• Filtration method should include for large scale production but small scale or domestic
used filtration method may ignore.
54

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