ABSTRACT
This work focused on the production and testing of biodegradable grease from Balanites aegyptiaca seed kernel oil. This was carried out by extracting the oil from the seeds using solvent n-Hexane extraction and reacting a given quantity of the extracted oil with a lithium soap to produce a lithium based biogrease. Consistency tests, drop point as well as gear wear tests were conducted on the developed biogrease samples and the results compared against that of a commercially available petroleum-based lithium grease -OANDO Crown grease EP2. The results showed that the oil combines with lithium stearate on a percentage weight basis of between 70% to 80%. Worked penetration values of the grease samples indicated a grease of consistency classification NLGI „0‟. Dropping point values for the biogrease ranged from 65⁰C to 161⁰C with increasing dropping point value as percentage concentration of base oil increases, peaking at 161⁰C for 80% base oil. The cost of productionfor the bio grease was also calculated. The developed biogrease also showed good antiwear characteristics comparable to commercially available mineral grease.
TABLE OF CONTENTS
Contents ………………………………………………………………………………………….page
COVER PAGE…………………………………………………………………………………………………………………………….. i
TITLE PAGE …………………………………………………………………………………………………………………………….. iii
DECLARATION ……………………………………………………………………………………………………………………….. iv
DEDICATION …………………………………………………………………………………………………………………………… vi
ACKNOWLEDGEMENT ………………………………………………………………………………………………………….. vii
ABSTRACT …………………………………………………………………………………………………………………………….. viii
TABLE OF CONTENTS …………………………………………………………………………………………………………….. ix
LIST OF FIGURES …………………………………………………………………………………………………………………… xiv
LIST OF TABLES …………………………………………………………………………………………………………………….. xv
LIST OF PLATES …………………………………………………………………………………………………………………….. xvi
NOMENCLATURE …………………………………………………………………………………………………………………. xvii
CHAPTER ONE …………………………………………………………………………………………………………………………. 1
1.0 INTRODUCTION …………………………………………………………………………………………………………………. 1
1.1 Background to the Study ………………………………………………………………………………………………… 1
1.2 Statement of Research Problem ………………………………………………………………………………………. 3
1.3 The Present Research ……………………………………………………………………………………………………. 5
1.4 Aim and Objectives ……………………………………………………………………………………………………….. 5
1.4.1 The specific objectives ………………………………………………………………………………………………….. 5
1.5 Scope of The Study ……………………………………………………………………………………………………….. 6
1.6 Significance of The Research …………………………………………………………………………………………. 6
1.7 Limitations ………………………………………………………………………………………………………………….. 7
CHAPTER TWO ………………………………………………………………………………………………………………………… 8
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2.0 LITERATURE REVIEW ……………………………………………………………………………………………………….. 8
2.1 Types of Grease and Their Chemical Composition ……………………………………………………………. 8
2.2 Classification of Greases ………………………………………………………………………………………………. 11
2.2.1 Sodium soap grease ………………………………………………………………………………………………. 11
2.2.2 Calcium soap grease……………………………………………………………………………………………… 11
2.2.3 Lithium soap grease ……………………………………………………………………………………………… 12
2.2.4 Barium soap grease ………………………………………………………………………………………………. 13
2.2.5 Aluminium soap grease …………………………………………………………………………………………. 13
2.2.6 Other greases ……………………………………………………………………………………………………….. 13
2.2.7 Clay based grease …………………………………………………………………………………………………. 14
2.2.8 Polyurea Greases ………………………………………………………………………………………………….. 14
2.3 Uses of Grease ……………………………………………………………………………………………………………. 15
2.3.1 Applications Suitable for Grease ……………………………………………………………………………. 15
2.3.2 Functional Properties of Grease ……………………………………………………………………………… 15
2.3.3 Characteristics of grease ……………………………………………………………………………………….. 16
2.4 Manufacture of Lubricating Greases ………………………………………………………………………………. 19
2.4.1 Basic Process for Manufacturing Lithium Grease …………………………………………………….. 19
2.5 Standard Tests for Grease Performance ………………………………………………………………………….. 20
2.5.1 Hardness/Consistency tests ……………………………………………………………………………………. 21
2.5.1.1 Cone Penetration ………………………………………………………………………………………………….. 21
2.5.1.2 Mechanical Stability ……………………………………………………………………………………………. 21
2.5.1.3 Drop Point Procedure …………………………………………………………………………………………… 22
2.5.1.4 Oxidation Stability ………………………………………………………………………………………………. 23
2.5.1.5 Roll Stability ………………………………………………………………………………………………………. 23
2.5.1.6 Oil Separation (during storage) ……………………………………………………………………………… 24
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2.5.1.7 Water washout test ………………………………………………………………………………………………. 25
2.5.1.8 Water spray off test ……………………………………………………………………………………………… 26
2.5.1.9 Behaviour in the presence of water ………………………………………………………………………… 26
2.5.1.10 Grease life in ball bearings at elevated temperature high speed and load:FAG FE 9 ….. 27
2.5.1.11 Grease life in ball bearings at elevated temperature ………………………………………………. 28
2.5.1.12 Copper Corrosion ……………………………………………………………………………………………… 28
2.5.1.13 Dynamic Rust Test (EMCOR test) ……………………………………………………………………… 29
2.5.2 Extreme Pressure Tests ………………………………………………………………………………………… 30
2.5.2.1 Four (4) Ball Weld Test ……………………………………………………………………………………….. 30
2.5.3 Wear Prevention Tests …………………………………………………………………………………………. 32
2.5.3.1 Four (4) Ball Wear Test ……………………………………………………………………………………….. 32
2.5.3.2 Four (4) Ball Wear Test ……………………………………………………………………………………….. 33
2.5.4 Other physical and performance tests for grease ………………………………………………………. 33
2.5.4.1 Low Temperature Flow Pressure …………………………………………………………………………… 33
2.5.4.2 Penetration at Low Temperature ……………………………………………………………………………. 34
2.5.4.3 Apparent Viscosity (SOD) ……………………………………………………………………………………. 34
2.5.4.4 Low Temperature Torque …………………………………………………………………………………….. 34
2.5.4.5 Low Temperature ………………………………………………………………………………………………… 35
2.6 Previous Research Work ………………………………………………………………………………………………. 35
2.6.1 Review of Related Works ……………………………………………………………………………………… 36
2.6.2 Research Gap ………………………………………………………………………………………………………. 38
2.6.3 Desert date – Balanites aegyptiaca (Aduwa) ……………………………………………………………. 38
CHAPTER THREE …………………………………………………………………………………………………………………… 41
3.0 MATERIALS AND METHODS ……………………………………………………………………………………………. 41
3.1 Introduction …………………………………………………………………………………………………………………………. 41
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3.2 Seed Preparation …………………………………………………………………………………………………………. 41
3.2.1 Materials …………………………………………………………………………………………………………….. 41
3.2.2 Equipment …………………………………………………………………………………………………………… 41
3.2.3 Procedure For Seed Preparation ……………………………………………………………………………… 42
3.3 Oil Extraction ……………………………………………………………………………………………………………… 42
3.3.1 Materials ………………………………………………………………………………………………………………… 42
3.3.2 Equipment ………………………………………………………………………………………………………………. 43
3.3.3 Procedure for Extraction Of Base Oil ……………………………………………………………………… 43
3.4 Viscosity Measurement ………………………………………………………………………………………………… 45
3.4.1 Materials …………………………………………………………………………………………………………….. 45
3.4.2 Equipment …………………………………………………………………………………………………………… 45
3.4.3 Procedure for Determination of Viscosity ……………………………………………………………….. 46
3.5 Grease Formulation ……………………………………………………………………………………………………… 47
3.5.1 Materials …………………………………………………………………………………………………………….. 47
3.5.2 Equipment …………………………………………………………………………………………………………… 47
3.5.3 Procedure for Grease Production ……………………………………………………………………………. 48
3.6 Grease Testing ……………………………………………………………………………………………………………. 51
3.6.1 Materials …………………………………………………………………………………………………………….. 51
3.6.2 Equipment and Instrumentation ……………………………………………………………………………… 51
3.6.3………………………………………………………………………………………………………………………………….. 54
3.7 ……………………………………………………………………………………………………………………………………….. 55
3.7.1………………………………………………………………………………………………………………………………….. 55
3.7.2………………………………………………………………………………………………………………………………….. 55
3.7.3 Procedure for Dropping Point ………………………………………………………………………………… 56
3.8 Gear Wear Test …………………………………………………………………………………………………………… 56
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3.8.1 Materials …………………………………………………………………………………………………………….. 56
3.8.2 Equipment …………………………………………………………………………………………………………… 57
3.8.3 Procedure for Gear Wear Determination …………………………………………………………………. 59
CHAPTER FOUR ……………………………………………………………………………………………………………………… 60
4.0 RESULTS AND DISCUSSION …………………………………………………………………………………………….. 60
4.1 Viscosity Determination For Balanites aegyptiaca Seed Oil ……………………………………………… 60
4.2 Grease Formulation ……………………………………………………………………………………………………… 61
4.3 Consistency Tests ………………………………………………………………………………………………………… 62
4.3.1 Worked and Unworked Penetration Tests ………………………………………………………………… 62
4.3.2 Dropping Point Tests ……………………………………………………………………………………………. 64
4.3.3 Gear Wear Test ……………………………………………………………………………………………………. 65
4.4 Costs ………………………………………………………………………………………………………………………….. 67
CHAPTER FIVE ………………………………………………………………………………………………………………………. 70
5.0 CONCLUSION AND RECOMMENDATIONS ………………………………………………………………………. 70
5.1 Conclusions ………………………………………………………………………………………………………………… 70
5.2 Recommendations ………………………………………………………………………………………………………. 70
REFERENCES …………………………………………………………………………………………………………………………. 72
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CHAPTER ONE
1.0 INTRODUCTION
1.1 Background to the Study
Olive oil was used as a lubricant as far back as 1650 BC. Various oils obtained from olive, rapeseed, castor beans, palm oil, and the fats from sperm whale, animal lard, and wool grease were used from around AD 50 until the early 19th century Sharma et al, (2006). The proliferation of machinery and machine components was unprecedented during the industrial revolution of the late 18th century – 19th century. This gave rise to a need to prolong the life of machine parts by reducing metal to metal contact, hence increasing useful working life of machine components. Lubrication was therefore not unknown, but its necessity was simply amplified during this period. A lot of substances and materials were therefore used as lubricants during this period with oils and fats from natural sources topping the list Haycock et al, (2004). These natural oils had limited stability. Serious efforts were initiated in the 1930s to develop synthetic lubricants for operation over wide temperature ranges (Sharma et al, 2006). However, the discovery of Crude oil changed that, soon after, almost all lubricants were made from petroleum products.
A lubricant is a substance designed to separate moving parts thereby minimizing friction and reducing wear. Greases are lubricating fluids that have been thickened with a gelling agent. A functioning grease should remain in contact with, and lubricate, the moving surfaces. It should not leak out under gravity or centrifugal action, or be squeezed out under applied pressure. Greases are the most versatile lubricant and are usually the first choice in lubricant selection due to their ease of application, lower maintenance requirements, fewer sealing requirements, greater effectiveness in stop and start conditions, and overall lower cost (Sharma et al, 2006).
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The use of petroleum products as lubricants presents its own problems. First is the issue of exhaustibility. It is estimated that world oil reserves will dwindle and by the turn of the next century, there would not be enough reserves for the world demand at that time. Also since the 1970‟s Oil prices have steadily increased and coupled with dwindling reserves and rising demand, crude oil prices would reach uneconomical levels for common use. Secondly, there is the problem of environmental pollution. Mineral Oils (from petroleum) used as base oil for lubricants are not easily assimilated by the environment (Biodegradability) Aluyor et al ,2009).. They present serious pollution problems when dumped into the ecosystem. There is therefore, a growing need to produce lubricants that are renewable, environmentally friendly and cheap. This is an integral part of the emerging “green” culture which stipulates the use of resources in a manner that is efficient, sustainable, renewable with less negative impact to the environment (Nosonovski and Bhanat, 2010).
Biogrease is part of the lubricant market and will likely grow substantially due to economic, environmental and legislative factors (Sharma et al, 2006). Biodegradable grease or biogrease can be produced either from natural oils or from chemical synthesis. These synthetic chemicals, even though they have superior performance characteristics to vegetable oils when used as base oils, they are often very expensive to produce. This need for cheap, environmentally friendly and renewable lubricants has given rise to a renewed research interest and today, vegetable oils are drawing attention as biodegradable alternatives for synthetic esters as they are less expensive and are available from renewable sources (Stefanescu et al 2011).
Machinery use in applications that require intimate contact with the natural environment, such as agriculture, forestry and some earth moving equipment or the food processing industry all require that a safe (non toxic) substance be used as lubricant Barriga et al, (2006). Also a
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significant percentage of all used lubricants find their way into the environment. The use of biogrease will neutralize the effect of improper disposal or discharge of this into the environment.
The use of vegetable oils as energy sources or as feedstock for biodegradable lubricants presents its own dangers. Fear is being expressed by experts over the impact of cultivation of energy crops and its competition with food cultivation. These fears, have necessitated a shift towards natural but inedible or non food oils. There is abundance of some of these natural oils derived mostly from wild sources or from tree borne oil seeds (TBO). Countries like India have already commenced the identification and determination of TBO and their potential as feedstock for energy and other uses (Nosonovsky and Bhanat, 2010).
It is thus clear, that the use of vegetable oils as base stocks for the production of biodegradable lubricants and greases would witness a rise in importance especially with the recent call for efficient and sustainable use of bioresources. In laying the foundations for green tribology, Nosonovsky and Bhanat (2010), listed the use of biodegradable lubricants as one of the pillars of the discipline.
1.2 Statement of Research Problem
Nigeria is the most populous country on the African continent and coupled with its abundant oil reserves, it has become a home to millions of vehicles WHO, (2013). This is apart from, motorcycles, industrial, agricultural and general purpose machinery of all sorts. These machinery require lubrication and presently, the bulk of lubricants are manufactured from mineral (petroleum) based oils. It is estimated that petroleum greases accounted for 98% of all greases
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sold in the United States in 2004 (Landsdown, 2004 as in Sharma, 2006). It is also known that a significant portion of lubricants used are released into the environment.
There is no survey on the estimated quantity of grease consumed locally in Nigeria, but the number of vehicles would give a good idea on the quantity of multipurpose grease estimated to be consumed locally in Nigeria. This quantity certainly presents a genuine concern about its disposal because a very significant percentage of that would go to total loss, dry lubrication systems such as those found in earth moving equipment.
Environmental concern continues to increase due to pollution from excessive lubricant use and disposal, especially total loss lubricants. Over 60% of the lubricants used in the United States are lost to the environment (Erhan et al., 2006 as in Othman, 2009). A study in India, also estimated that 40% of all lubricants are released into the environment (Adhvaryu et al. 2005 as in Sharma (2006). It can thus, be safely assumed that a reasonable portion of lubricants consumed in this country is released into the ecosystem one way or another, since there is no organized disposal system for such.
The renewed interest in developing cheap, environmentally friendly and renewable lubricants world over has caused many countries to explore resources commonly available to them with a view to reap the benefits. Hence, lots of research has been undertaken in the US for instance on the suitability of using Rapeseed oil, canola oil, sunflower oil and castor oil while in India and some countries in SE Asia, Coconut oil, Rice bran oil, soybean oil, Palm Oil, Groundnut/Peanut oils have all been studied as possible alternative base oils for the production of bio lubricants (Nagendramma and Kaul, 2012). Vegetable oils even though a promising alternative present a veritable challenge since they are a source of food. The danger of using edible oils as base oils is an area of concern since it would mean instead of growing these oilseeds for their food value,
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they would be grown solely for the exploitation of their oil for energy and other uses. This obvious conflict has necessitated a shift in strategy towards the exploitation of non-edible oils and tree borne oilseeds (TBO‟s) which are not used as food especially those that occur in the wild. A study in India, identified over a 100 species of tree borne non-edible oilseeds and their source potential as feedstock for energy and other uses has been reported by Subbarao, (2006) as in Chauhan and Chhiber (2013).
1.3 The Present Research
This research focused on the extraction and use of desert date seed oil as a feedstock for Lithium biogrease. The desert date seed oil was extracted and the oil used as a base oil to produce a simple lithium grease. The Consistency, Drop point and wear characteristics values of this grease was evaluated and compared with a simple, mineral oil based grease. This served to show the viability of B.aegyptiaca seed oil as base oil for the production of Lithium grease which can be used safely in agricultural machinery, forestry, mining, food processing and other areas in which the application of environmentally friendly grease is desirable.
1.4 Aim and Objectives
The aim of this research is to investigate the suitability of Desert Date seed oil as base oil with metal (Lithium) soap as thickener for production of biogrease.
1.4.1 The specific objectives
The specific objectives of this work are:
i. To extract the crude oil from the Desert Date seed
ii. To formulate and develop biodegradable Lithium grease from the extracted Desert Date seed oil.
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iii. To conduct cone penetration, dropping point and wear characteristics tests on the developed grease.
iv. To carry out comparative analysis of the developed grease with petroleum based Lithium grease in order to determine its suitability as a complement for petroleum based grease.
1.5 Scope of The Study
This research work looked at the suitability or otherwise of using Balanites aegyptiaca (Desert date seed oil) to produce biodegradable Lithium grease, by varying the amount of base oil from 70% through 80% by weight to produce a set of biogrease samples and also the addition of the antioxidant, Diphenylamine (DPA) to produce four samples of the bio grease. The resulting biogrease samples were then subjected to consistency tests for worked and unworked penetration (ASTM D217), drop point tests (ASTM D566) and gear wear test (ASTM D4048). A sample of commercially available Multipurpose (Petroleum) Lithium grease (OANDO Crown EP2) (control) was then subjected to the same tests as the biogrease and the results were compared.
1.6 Significance of The Research
The current trend all around the world is towards environmentally friendly lubricants from renewable sources that are envisaged to eventually replace toxic, non renewable mineral oils. Vegetable oils offer a promising alternative but they present a veritable challenge since they are a source of food. This obvious conflict has necessitated a shift in strategy towards the exploitation of non-edible oils and tree borne oilseeds (TBO‟s) which are not used as food especially those that occur in the wild. Balanites Aegyptiaca or desert date seed is a wild growing TBO. It is quite cheap and is easily locally sourced especially in the Sahel belt of the
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country where it is in plentiful supply. Its oil has been characterized as a viable feedstock for biodiesel production. There is therefore a need to exploit this resource in the quest for a cheap, renewable and environmentally friendly feed stock for biogrease as an alternative grease to petroleum based grease in case of high cost and scarcity of petroleum. Finally, to obtain a biodegradable grease.
1.7 Limitations
In the course of this research, only three tests were considered namely penetration values, dropping point and wear characteristics, initially copper corrosion test was proposed but due to the high cost it was abandoned. Presently, only Petroleum Training Institute, Effurun, Delta State carries out copper corrosion test.
Even the wear test was improvised as there is no facility in the country to conduct the standard wear tests. Other tests also, need to be carried out to provide a better picture of the characteristics and performance of the developed biogrease from Balanites aegyptiaca with Lithium stearate as thickener.
Other thickeners like Sodium, Calcium, Magnesium and Aluminium soaps have not been utilized.
Also most of the chemical additives proposed were unobtainable in the country. Proposal for imports required huge quantities not suitable for laboratory scale work.
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