SYNTHESIS OF BIOLUBRICANT FROM VEGETABLE OILS

ABSTRACT

This thesis aimed at the production of biolubricant from vegetable oils. The first stage produced methyl ester of the oil and in the second stage; the methyl ester was transesterified with Trimethylolpropane (TMP) in a ratio of 3.5:1 at 150⁰C to produce the biolubricant. The pour points biolubricant and its blend were significantly improved when compared to that of raw oils. The pour point for Jatropha oil improved from 6.5 to -8 to -13, Moringa oil from 6 to -8 to -15, Castor oil from 5 to -4 to -30 and Cotton seed oil from 4°C to -6°C to -16°C respectively. Similarly the viscosity index of Jatropha oil reduced from 220.70 to 216, Moringa oil from 224.70 to 197.75, Castor oil from 96.42 to 88.32, and Cotton seed oil from 213.12 to 198.57 respectively. As the temperature increased from 30⁰C to 100 the viscosity reduces by 37.97, 53.46, 69.58 and 39.32 cSt. The GC-MS result shows that the oils contained more of unsaturated ricinoleic, and linoleic acid than saturated fatty acid of caproic, capric, palmitic and stearic acid. It was found that the biolubricant produced was comparable to the ISO VG-32 and VG-46 commercial standards for light and industrial gears applications respectively.

CHAPTER ONE

INTRODUCTION

1.1 PREAMBLE

The environmental threats posed by the fossil fuels are currently a major global concern. Fossil fuels are increasingly associated with the emissions of greenhouse gases, majorly CO₂, leading to climate change, emergence of drought, spread of diseases and variation in population sizes of both plant and animal species (Lashof and Ahuja, 1990). The depletion of the world’s crude oil reserve, increasing crude oil prices, and issues related to conservation have brought about renewed interest in the use of bio-based materials. Fossil fuels such as petroleum, coal and natural gas, which have been used to meet the energy needs of man, are associated with negative environmental impacts such as global warming (Munack et al., 2001; Saravanan et al., 2007). Supply of these non-renewable energy sources is threatening to run out in a foreseeable future (Sambo, 1981; Munack et al., 2001). It has been widely reported that not less than ten major oil fields from the 20 largest world oil producers are already experiencing decline in oil reserves.

The contact pressures between devices in close proximity and moving relative to each other are usually sufficient to cause surface wearing, frictions and generation of excessive heat without protector (Hassan et al. 2006). These friction, wear and excessive heat have to be controlled by a process or technique called lubrication. Lubrication is the process or technique employed in reducing wear or tear of one or both surfaces in close proximity and moving relative to each other by interposing a substance called lubricant between the surfaces to carry    the load between     the opposing surfaces (Hassan et al. 2006; Parsons, 2007).

Synthetic biolubricant based on renewable resources are important in developing environmentally acceptable lubricating oils. Currently, lubricant-based petroleum worldwide end up in the environment via total loss applications, spills, or major accidents. A fact remains that about 3million tonnes are lost in the European environment every year originating from loss of high-risk lubricants mostly based on mineral oil. Modern approaches have been adopted to solve the problems associated with application of vegetable oils in biolubricants, and some of them used for chemical modification and additive treatment (Erhan, 2005).

Emphasis on the development of renewable, biodegradable, and environmentally friendly industrial fluids, such as diesel, lubricants and other fuels has resulted in the widespread use of natural oils and fats for non-edible purposes. A lubricant is a substance (often a liquid) introduced between two moving surfaces to reduce the friction between them, improving efficiency and reducing wear. Biodegradable lubricants have been formulated from crude plant oil to chemically modified plant oil with properties better than mineral oil lubricants (Ghazi et al., 2010). These ecological friendly lubricants are obtained from either edible or non-edible plant among which are castor, moringa, cotton and Jatropha curcas.

Many studies have confirmed that the monounsaturated fatty acids in plants oils, such as oleic and palmitic, are considered as the best candidates for lubricants and hydraulic oils (Rudnick, 2006). Any plant oils with a high concentration of saturated linear fatty acids are not desirable for lubricant production because they generally appear as solid form at room temperature. Oleic acid has been proved by many studies as the most ideal mono-saturated fatty acid for biolubricant application. Many studies have also confirmed that the plant oils extracted from the crops with a high concentration of oleic acid, such as canola/rapeseed and castor seeds, are the most desirable plants oils for biolubricant production (Rudnick, 2006). Jatropha is a non-edible plant that was recently discovered to have great potential as feedstock for biodiesel and biolubricant (Banerji, 1985). The oil is considered non-edible oil due to the presence of toxic esters (Shah et al., 2004). Thus, it provide an alternative of sufficient supplies of low cost feedstock for fuel oil and its derivatives with no competition with food uses (Ghazi et al., 2010).Cottonseed oil like any other vegetable oil such as sunflower oil, palm oil could be used as an alternative to mineral lubricant but no record has been found on it lubricant properties to critically exploit it for this purpose. Castor is a nonedible plant that was recently discovered to have great potential as feedstock for biodiesel and also biolubricant (Banerji, 1985). Eckey (1954) reported that the moringa oil is unusually resistant to the development of rancidity and recommended it as suitable for effleurage and as a lubricant.

The present work sought into production of biolubricant from vegetable oils source (Jatropha, Moringa, Castor, and Cotton seed oil) with improved physico-chemical properties such as pour point, viscosity index, and temperature stability.

1.2 RESEARCH PROBLEM

Lubricants derived from petroleum base are widely used in almost all applications. However its non-biodegradable properties have made a serious problem in terms of environmental pollution. This aroused the need to develop lubricants from non-fossil sources. Low-temperature studies have shown that most vegetable oils undergo cloudiness, poor flow, and solidification at cold temperatures.

1.3 RESEARCH AIM

This research is aimed at the production of bio-lubricant from Jatropha, Moringa, Castor and Cotton seed oil using two stage transesterification reaction.

1.4 RESEARCH OBJECTIVES

The aim will be realized through the following objectives:

1. To produce the biolubricants.
2. To determine the physico-chemical properties of the synthesized biolubricant and compare with ISO VG requirement.
3. To study the fatty acid composition of the synthesized biolubricant produced and infrared spectrum of the trimethylolpropane (TMP) used for the polyol ester synthesis.
4. To investigate the effect of temperature on viscosity of the synthesized biolubricant blend with mineral base oil.

1.5 JUSTIFICATION

Lubricant with higher viscosity index tends to exhibit less viscosity change with temperature. Less emission due to higher boiling temperatures ranges of esters. Biodegradability and high cleanliness at the working place with higher wetting tendency of polar esters which lead to friction reduction.

1.6 SCOPE OF THE RESEARCH

The scope of this research work covered collection of materials, production of biolubricants, physic-chemical determination and chemical modification in order to enhance their suitability for ISO viscosity grades requirement by adopting the following;

1. Esterification reaction
2. Methyl ester and polyol ester synthesis
3. Characterization of the raw oils, synthesized biolubricant and trimethylolpropane (TMP) using
4. Qualitative measurement
5. Fourier Transform Infrared Spectrum (FTIR)
6. Gas Chromatography – Mass Spectrometry (GC-MS)
7. Effect of temperature on viscosity

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