HOMOGENOUS FUEL BLEND AND

METHOD OF PREPARING THE BLEND

INTRODUCTION

This invention relates to a blended homogenous fuel product comprising a fossil fuel component, preferably petrol, and an alcohol component, preferably ethanol, more preferably bioethanol. The invention further relates to a method of preparing the fuel product.

BACKGROUND

As a result of the ever increasing concern over fossil fuel usage and its contribution to the Greenhouse Effect, growing concerns over climate change, and increasingly stringent air quality regulations, renewable energy has become of growing importance. Furthermore, there exists an opportunity and favourable economic conditions for the increased production and application of alternative fuels such as ethanol, in particular bioethanol. An ethanol-petrol fuel blend is more practical than ethanol alone, could improve engine performance, and decreases exhaust emissions.

It is well known that the addition of oxygenates to petrol can be used to overcome the problem of increasing the octane number of petrol to the required level. The spectrum of oxygenates currently used is broad, including: ethers such as methyl tert-butyl, methyl tert-amyl, ethyl tert-butyl, and diisopropyl, and alcohols such as methanol, ethanol, and certain higher alcohols.

The use of alcohols, including methanol and ethanol, as oxygenates is desirable because alcohol-petrol blends have engine properties that compares favourably to those of traditional petroleum based fuels. Despite its high blending octane number, the use of methanol is limited, and in many countries prohibited, due to its high toxicity, volatility, and hygroscopicity.

Rasskazchikova et al. (2004) has stated that ethanol was previously relegated to "the second tier" because of its relatively high cost. However, recently ethanol has again become more competitive as a result of new continuous fermentation manufacturing processes instead of the old cyclic processes, together with the gradual and continuous increase in the price of petrol.

Compared to methanol, ethanol is less hygroscopic, has a higher heat of combustion and lower evaporation, and is less toxic. It is well known that ethanol, and ethanol blended fuels, can assist in the reduction of air polluting emissions from internal combustion engines including carbon monoxide, unburned hydrocarbons, nitrogen oxides, and particulate material, whilst at the same time, maintaining and perhaps even improving engine performance in modern vehicles. In addition, there is growing interest in the increased use of ethanol in fuel blends due to the possibility of producing it from renewable plant stock. The aforementioned advantages have all contributed to the increased use of, and interest in, ethanol in fuel blends.

During the late 1970's, the phasing out of leaded petrol began. Methyl tert- butyl ether (MTBE) and ethanol were then added to petrol to improve the octane rating and to reduce emissions. However, ethanol recently surpassed MTBE as the additive of choice, becoming the most attractive oxygenate due to the environmental and health concerns associated with MTBE including its high solubility in water, toxicity, and degradation products. Ethanol is an oxygenated hydrocarbon with a high octane rating. It may be blended with petrol in various proportions. A volume fraction of 5 to 10% of ethanol can achieve the maximal Reid Vapor Pressure (RVP), facilitating cold- start. Ethanol also has a higher octane number than petrol, thus by increasing engine compression ratio, both the efficiency and power can be increased. Further, it has been shown that the addition of ethanol to petrol results not only in the increase of the RVP of the blended fuel, but it also changes its fuel distillation curve and composition. Depending on the circumstances and the desired fuel, ethanol can be blended with petrol at any ratio, including E5, E10, E20, E25, E70, E85, E95 and E100, which contain 5, 10, 20, 25, 70, 85, 95 and 100% ethanol respectively.

However, there are certain disadvantages associated with the addition of ethanol to petrol. These include the potential increase (or decrease) of the RVP, the alteration of distillation properties, and critically the prevention of transportation in pipelines due to the risk of water-induced phase separation.

Generally, ethanol-petrol fuel blends are sensitive to moisture and have a tendency to separate into two layers when exposed to relatively small volumes of water. On exposure to water, the ethanol-petrol fuel blend will first absorb water until a point at which the quantity of water added is greater than its solubility in that blend. A separate layer then forms.

The main concern associated with phase separation in ethanol-petrol fuel blends is that ethanol preferentially partitions into the aqueous layer, resulting in an ethanol-rich aqueous layer and ethanol-deficient petrol layer. This ethanol-deficient petrol layer then has a reduced octane rating and may not function satisfactorily as a fuel.

The issue of phase separation of ethanol-petrol blends could be addressed by an appropriate fuel formulation containing a surfactant additive; however, this results in an increased cost for the final fuel blend. Therefore, and in order for it to be commercially usable in fuel blends, it is desirable that water be removed from bioethanol. Most of the water can removed by distillation, but the purity that can be attained is limited due to the formation of a low-boiling water-ethanol azeotrope.

After traditional distillation, about 5% of water remains in ethanol. In azeotropic distillation, a third chemical, called an entrainer, is added into solution. In the case of ethanol, benzene or cyclohexane is typically chosen as an entrainer. An entrainer has a strong chemical interaction with the chemical to be separated. Thus, when an entrainer is introduced into solution, three phases appear. In the case of ethanol and water, one layer is almost pure water, another is pure ethanol, and the other is the mix of three compounds. However, the use of an entrainer could contaminate the desired compound, and there are potential safety issues associated with this method, such as flammability and toxicity.

Another method of dehydrating bioethanol is through the use of molecular sieves. The sieves have many pores, and while the entrances to these pores are small, the inner cavities of the pores are relatively large. The pore size of the molecular sieves used for ethanol dehydration is generally around 3 Angstroms. This is considered ideal due to the relative size of the ethanol and water molecules respectively. Thus, this pore can adsorb water molecules and reject ethanol molecules. While molecular sieves have more advantages than azeotropic distillation, some problems remain. It requires significant energy input to regenerate the used sieves, and high pressured ethanol is extremely flammable.

There have therefore been challenges in the production of acceptably pure bioethanol, most notably the production cost associated which the process of water removal. Known production methods of high purity bioethanol require a large consumption of energy, or the use of expensive purification agents.

There is therefore a need for a blended fuel product comprising fossil fuel and an ethanol that will not phase separate as a result of the presence of water. SUMMARY OF THE INVENTION

According to a first aspect to the present invention there is provided a method of preparing a blended homogenous fuel product, the method comprising providing a fossil fuel component and an alcohol component, and mixing the components through ultrasonic energy, wherein the homogenous fuel product comprises from about 1 to about 45 v/v% water by volume of the alcohol component.

Preferably, the homogenous fuel product comprises from about 5 to about 40 v/v% water by volume of the alcohol component.

More preferably, the homogenous fuel product comprises from about 10 to about 40 v/v% water by volume of the alcohol component.

Even more preferably, the homogenous fuel product comprises from about 25 to about 35 v/v% water by volume of the ethanol component.

The fossil fuel component is preferably petrol.

In a particularly preferred embodiment, the homogenous fuel product comprises substantially no surfactant.

The alcohol component may be ethanol, preferably the alcohol component is bioethanol.

The ultrasonic energy may be provided by at least one ultrasonic horn.

Preferably, the ultrasonic energy has a frequency of from about 15 kHz to about 500 kHz, more preferably from about 15 kHz to about 50 kHz, most preferably the ultrasonic energy has a frequency of about 24 kHz.

According to a second aspect to the present invention there is provided a blended homogenous fuel product comprising a fossil fuel component and an alcohol component, wherein the fuel product is mixed through ultrasonic energy, and wherein the homogenous fuel product comprises from about 1 to about 45 v/v% water by volume of the alcohol component.

Preferably, the homogenous fuel product comprises from about 5 to about 40 v/v% by volume of the alcohol component.

More preferably the homogenous fuel product comprises from about 10 to about 40 v/v% by volume of the alcohol component.

Even more preferably, the homogenous fuel product comprises from about 25 to about 35 v/v% by volume of the alcohol component.

The fossil fuel component is preferably petrol.

In a particularly preferred embodiment, the homogenous fuel product comprises substantially no surfactant.

The alcohol component may be ethanol, preferably the alcohol component is bioethanol.

The ultrasonic energy may provided by at least one ultrasonic horn.

Preferably, the ultrasonic energy has a frequency of from about 15 kHz to about 500 kHz, more preferably from about 15 kHz to about 50 kHz, most preferably the ultrasonic energy has a frequency of about 24 kHz.

According to a third aspect to the present invention there is provided a fuel product prepared according to the method of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail with reference to the following non-limiting embodiments and Figures in which: Figure 1 shows a schematic representation of the sonochemical reactor setup as used in the method of the present invention;

Figure 2 shows a graph of the ethanol concentration as a function of the distance from the ultrasonic horn of the ultrasonicator;

Figure 3 shows a diagram of binodal curves for fuel blend mixtures prepared as described; and

Figure 4 shows a diagram comparing the binodal curves of ethanol- petrol-water fuel blends before and after separation due to sonication.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

The present invention will now be described more fully hereinafter with reference to the accompanying figures, in which some of the embodiments of the invention are shown.

The invention as described hereinafter should not be construed to be limited to the specific embodiments disclosed, with slight modifications and other embodiments intended to be included within the scope of the invention. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

As used throughout this specification and in the claims which follow, the singular forms "a", "an" and "the" include the plural form, unless the context clearly indicates otherwise.

The terminology and phraseology used herein is for the purpose of description and should not be regarded as limiting. The use of the terms "comprising", "containing", "having", "including", and variations thereof used herein, are meant to encompass the items listed thereafter and equivalents thereof as well as additional items. As used throughout this specification and in the claims which follow, unless the context indicates otherwise, the term:

"Fossil fuel" refers to a range of liquid hydrocarbon fuels produced from nonrenewable sources such as coal, petroleum, and natural gas.

"Petrol" or "gasoline" is used interchangeably and refers to the petroleum derived oil mainly used as a fuel for combustion engines. It comprises mostly organic compounds obtained by the fractional distillation of petroleum.

"Ultrasonication" means the process of mixing components or particles using ultrasonic energy. Ultrasonication involves cavitation (bubble formation and collapse) and intense mixing of the liquid.

"Sonochemical reactor" means a device that is capable of generating power ultrasound from mechanical or electrical energy.

"Ultrasonic horn" means an immersion type of transducer where very high intensities (pressures of the order of thousands of atmospheres) are observed close to the horn. This intensity decreases at an exponential rate as the distance from the horn increases until the intensity disappears altogether. Ultrasonic horns are the most frequently used reactor designs in sonochemical reactors.

"Cavitation" refers to formation, growth, and rapid implosive collapse of vapour filled micro bubbles. Acoustic cavitation is the effect which takes place when a sufficiently high-amplitude ultrasonic signal is propagating in a liquid.

"Homogenous blend" refers to a blend that is essentially uniform in character, and as used in this specification refers in particular to liquid blends that consist essentially of a single phase.

"Surfactant" refers to a compound that contains both hydrophobic and hydrophilic groups thereby increasing the solubility of one solvent in another. The present invention relates to a blended homogenous fuel product comprising a fossil fuel component, which is preferably petrol, and an alcohol component. The alcohol component is preferably ethanol, more preferably bioethanol. The invention further relates to a method of preparing the fuel product.

A batch reactor (10), as is schematically shown in Figure 1, with marked off radii ranging from 1 cm to 4 cm was set up to conduct the below described fuel blending experiments. Thermometers (not shown) were placed and secured at the 1cm, 3cm and 4cm points. The ultrasonic horn (11) was placed in the centre of the reactor vessel (12). The container (12) further comprised an inlet (13) and an outlet (14). The ultrasonic horn (11) operated at a frequency of 24 KHz. The batch reactor was irradiated using a single ultrasonic horn kept towards the bottom of the reactor. The inner cross- section of the batch reactor has dimensions of 5 cm (diameter) x 33 cm (height) with a total holding capacity of 0.65L. In the batch reactor, cavitation or cavitational energy, created by ultrasonic horn, was used to mix the fuel components.

The mixing time 9 is calculated from equation (a) below, and depends on the fuel mixing ratio, the ultrasonic horn position, the velocity of the horn and the fluid viscosity and density.

v _h = 24xl0 ³ A (b)

In this equation, d is a distance between horn tip and bottom of reactor, Vh is the velocity of horn (V _h = (A) amplitude of oscillation in m * frequency in Hz), μ is viscosity of the mixed fuel (N s/m ² ) and pi is the bulk density of the mixed fuel (kg/m ³ ).

Table 1 : Dimensions and operating parameters for the batch reactor

Frequency of ultrasonic horn 24 KHz

Volume capacity 600ml

Diameter 5cm

Height 33cm Petrol and ethanol were blended in various proportions ranging from 5 to 25 v/v% ethanol, increasing in increments of 5%. The fuel blends were prepared according to the data tabulated in Table 2 below:

Table 2: Experimental blends of petrol and ethanol

For each experiment number (1 - 5), the volume of petrol under investigation was first poured into the batch reactor. The ultrasonic horn was then lowered to approximately 2cm below the surface of the petrol before being switched on. The temperature of the petrol was then monitored until it reached 40 deg C, at which point the appropriate volume of ethanol was added to the petrol at a constant rate. After 60s, the ultrasonicator was switched off and 1.5ml samples were collected from each marked off point using a micropipette. The samples were stored in glass vials and sealed. The corresponding temperature readings were also recorded. The batch reactor was then drained and the above process repeated, with run times of 120s, 240s, 300s, 360s and 420s respectively. The samples were analysed for ethanol concentration using an Abbe refractometer.

Figure 2 shows a plot of the ethanol concentration as a function of the distance from the ultrasonic horn of the ultrasonicator. The results presented in Figure 2 are results obtained after a blending time of 60s for the different ethanol-petrol blends 1 - 5 in Table 2.

As can be seen from Figure 2, the change in concentration of ethanol resembles a wave function. Without thereby wishing to be bound by the confines of theory, it is believed that the ethanol concentration wave function is a result of the waves created by the ultrasonic horn. Also, it is believed that, due to the relatively small volume of the reactor, the waves propagate through the ethanol-petrol blend and are reflected back as they reach the end of the reactor vessel.

Furthermore, the results indicate that there is cavitation occurring during the blending of petrol with ethanol when using the ultrasonicator. The troughs and crests of the wave are an indication of contraction and expansion of the cavitation bubble respectively. The amplitude of the wave is not the constant; this is because the intensity of the wave decreases as distance from the ultrasonic horn increases. The trend observed for a blending time of 60s was consistent with the alcohol concentration results obtained by blending times of 120s, 240s, 300s, 360s and 420s.

Further, from Figure 2 it is evident that there is slight decrease in concentration from a distance of 1cm to 4cm. This is believed to be due to the diffusion of ethanol, occurring as a result of a difference in concentration gradients.

For each of experiment number 1 - 5 in Table 2, after a run time of 420s, 5 ml of water was added to the ethanol-petrol fuel blend. The fuel blend was then allowed to stand for 10 minutes and investigated for phase separation, i.e. indicated by the blend initially being cloudy, followed by a gradual formation of two separate liquid layers: a lower ethanol-water layer and an upper ethanol- petrol layer.

In this specification the mixing efficiency of the method is defined as a measure of the homogeneity of the ethanol-petrol fuel blends. A homogenous mixture is one where the components which are mixed cannot be physically identified. Concentration gradients were thus used to measure how well ethanol and petrol mixtures were blended. The various ratios of ethanol and petrol were blended for 420s using the experimental set up of Figure 1. The concentration gradient results for each blend are provided in Table 3 below. From the results shown in Table 3, it appears that the 0% ethanol-petrol fuel blend had the lowest concentration gradient (2.63 vol%/cm), and thus that it was the most homogenous of the fuel blends prepared.

Table 3: Concentration gradients for various ethanol-petrol fuel blends after a blending time of 420s

The various ethanol-petrol fuel blends showed no evidence of phase separation after a standing time of 10 minutes following the addition of 5mL of water to the ethanol-petrol fuel blends. The results are presented in Table 4 below.

Table 4: Physical phase separation data for various ethanol-petrol fuel blends

Further experiments were conducted to investigate the differences in conventional blending and ultrasonication using an ultrasonic horn. As stated above, when fuel containing even small amounts of ethanol comes in contact with water, either in the form of liquid or in the form of humidity; the ethanol will absorb some or all of that water. When it reaches a saturation point the ethanol and water will phase separate, coming out of solution and forming two or three distinct layers. Phase separation is also temperature dependent. The blending techniques were evaluated to investigate if the two components can be mixed when the ethanol contains water. Table 5 and 6 below summarise the experimental findings.

Table 5: Mixing ethanol and petrol using magnetic stirrer at 27 deg C

(5 % ethanoi and 95 % petrol)

Table 6: Mixing ethanol and petrol using a sonication horn at 27 deg C

(5 % ethanol and 95 % petrol)

Water content in Storage for 1 Storage at 0

Observations

volume % week deg C

0.1 Homogenous homogenous homogenous

0.2 Homogenous homogenous homogenous

0.3 Homogenous homogenous homogenous

0.4 Homogenous homogenous homogenous

0.5 Homogenous homogenous homogenous

0.6 Homogenous homogenous homogenous

0.7 Homogenous homogenous homogenous

0.8 heterogeneous heterogeneous heterogeneous

0.9 heterogeneous heterogeneous heterogeneous 4

Further experiments were conducted to observe the effect of ultrasonic energy on petrol-ethanol-water blends by observing what happens to the blends that lie on the existing binodal curve of the ternary mixture diagram as well as the mixtures that lie below and the above this curve at ca. 25 deg C.

Usually traditional mixing methods are employed industrially to form a mixture of these components, and there is currently no known use of an alternative, ultrasonic, method of mixing petrol-ethanol-water fuel blends. The mixtures that represented by the points on the binodal curve were prepared as well as the mixtures that represented the points below this curve.

One way in which to study ternary mixtures is by the use of triangular diagrams. The ternary diagram essentially contains sloping straight lines, which are referred to as tie lines, and the curved line, known as the binodal curve. The points on this line and above this line represent a single phase that does not separate into two immiscible phases, whereas the area that lies beneath this curve represents the formation of two phases that are at equilibrium with each other.

As water dissolves in petrol, the maximum amount of water that petrol is capable of absorbing is reached and an equilibrium is reached. At this point any excess water will not dissolve, resulting in the formation of two separate phases comprising different concentrations of ethanol. Generally, the amount of water that petrol is capable of absorbing depends on the temperature as well on pressure of the system.

The samples were prepared using three separate beakers and three separate syringes. The syringes were used to transfer the mixture components into a separate beaker to form the mixtures shown in Table 7. The mixtures were then sonicated for about 5 minutes using an ultrasonicator. The binodal curves for the mixtures after sonication are shown in Figure 3 (homogenous and heterogeneous). Table 7: Proportion in class of the mixture

Sample Sample Sample

Proportion in class (%) Proportion in class (%) Proportion in class (%) No No No

ethanol water petrol ethanol water petrol ethanol water petrol

Curve 1 Curve 5 cont. Curve 9

1 0 0 100 93 29.0 11.0 60.0 181 0.0 0.0 100.0

2 10 1.75 88.25 94 33.0 12.0 55.0 182 2.5 2.5 95.0

3 17 3 80 95 36.6 13.4 50.0 183 5.5 4.5 90.0

4 20 3.5 76.5 96 40.0 15.0 45.0 184 12.0 8.0 80.0

5 30 5 65 97 43.5 16.5 40.0 185 18.0 12.0 70.0

6 40 7 53 98 46.6 18.4 35.0 186 25.0 15.0 60.0

7 50 11 39 99 49.5 20.5 30.0 187 27.5 17.5 55.0

8 60.0 16.5 23.5 100 52.0 23.0 25.0 188 31.2 18.8 50.0

9 62.0 18.0 20.0 101 53.0 24.5 22.5 189 34.0 21.0 45.0

10 63.0 24.0 13.0 102 54.0 26.0 20.0 190 38.0 22.0 40.0

11 62.0 28.0 10.0 103 53.8 28.7 17.5 191 41.0 24.0 35.0

12 60.0 32.5 7.5 104 53.0 32.0 15.0 192 43.0 27.0 30.0

13 55.0 40.0 5.0 105 51.0 36.5 12.5 193 46.0 29.0 25.0

14 50.0 47.0 3.0 106 47.8 42.2 10.0 194 46.5 31.0 22.5

15 40.0 57.5 2.5 107 43.0 49.5 7.5 195 46.0 34.0 20.0

16 30.0 68.2 1.8 108 37.0 58.0 5.0 196 44.0 38.5 17.5

17 20.0 79.0 1.0 109 27.5 70.0 2.5 197 41.0 44.0 15.0

18 10.0 89.5 0.5 110 0.0 100.0 0.0 198 37.5, 50.0 12.5

19 0.0 100.0 0.0 199 32.5 57.5 10.0

200 28.0 64.5 7.5

Curve 2 Curve 6 201 22.0 73.0 5.0

20 0.0 0.0 100.0 111 0.0 0.0 100.0 202 13.0 84.5 2.5

21 7.6 2.4 90.0 112 3.4 1.6 95.0 203 0.0 100.0 0.0

22 16.3 3.7 80.0 113 6.9 3.1 90.0

23 25.0 5.0 70.0 114 14.0 6.0 80.0

24 32.7 7.3 60.0 115 21.0 9.0 70.0 Curve 10

25 37.0 8.0 55.0 116 28.0 12.0 60.0 204 0 0.0 100.0 41.0 9.0 50.0 117 31.0 14.0 55.0 205 2.5 2.5 95.0

44.5 10.5 45.0 118 35.0 15.0 50.0 206 5 5.0 90.0

48.0 12.0 40.0 119 38.5 16.5 45.0 207 11 9.0 80.0

52.0 13.0 35.0 120 42.5 17.5 40.0 208 17 13.0 70.0

55.5 14.5 30.0 121 45.7 19.3 35.0 209 24 16.0 60.0

57.7 17.3 25.0 122 48.0 22.0 30.0 210 27 18.0 55.0

59.0 18.5 22.5 123 50.7 24.3 25.0 211 30 20.0 50.0

60.0 20.0 20.0 124 52.0 25.5 22.5 212 32.3 22.7 45.0

60.5 22.0 17.5 125 52.5 27.5 20.0 213 36 24.0 40.0

61.0 24.0 15.0 126 52.0 30.5 17.5 214 38 27.0 35.0

60.5 27.0 12.5 127 50.7 34.3 15.0 215 41 29.0 30.0

60.0 30.0 10.0 128 48.0 39.5 12.5 216 42.5 32.5 25.0

57.5 35.0 7.5 129 45.0 45.0 10.0 217 42 35.5 22.5

52.0 43.0 5.0 130 40.0 52.5 7.5 218 41.5 38.5 20.0

43.5 54.0 2.5 131 33.0 62.0 5.0 219 39 43.5 17.5

0.0 100.0 0.0 132 24.0 73.5 2.5 220 37 48.0 15.0

133 0.0 100.0 0.0 221 33 54.5 12.5

Curve 3 222 30 60.0 10.0

0.0 0.0 100.0 223 24.5 68.0 7.5

3.6 1.4 95.0 224 20 75.0 5.0

7.4 2.6 90.0 Curve 7 225 15 82.5 2.5

16.1 3.9 80.0 134 0.0 0.0 100.0 226 0 100.0 0.0

24.0 6.0 70.0 135 3.1 1.9 95.0

32.0 8.0 60.0 136 6.0 4.0 90.0

36.0 9.0 55.0 138 13.0 7.0 80.0 Curve 11

40.0 10.0 50.0 139 20.0 10.0 70.0 227 0 0.0 100.0

43.0 12.0 45.0 140 27.0 13.0 60.0 228 2 3.0 95.0

47.0 13.0 40.0 141 30.0 15.0 55.0 229 4.9 5.1 90.0

50.2 14.8 35.0 142 33.0 17.0 50.0 230 10 10.0 80.0

53.2 16.8 30.0 143 37.0 18.0 45.0 231 16 14.0 70.0

56.6 18.4 25.0 144 40.0 20.0 40.0 232 21.5 18.5 60.0

57.5 20.0 22.5 145 43.0 22.0 35.0 233 25 20.0 55.0

58.1 21.9 20.0 146 47.0 23.0 30.0 234 27.5 22.5 50.0 58.4 24.1 17.5 147 49.0 26.0 25.0 235 30 25.0 45.0

58.4 26.6 15.0 148 49.9 27.6 22.5 236 33 27.0 40.0

58.3 29.2 12.5 149 50.0 30.0 20.0 237 36 29.0 35.0

56.4 33.6 10.0 150 49.0 33.5 17.5 238 38 32.0 30.0

52.5 40.0 7.5 151 47.5 37.5 15.0 239 39 36.0 25.0

47.2 47.8 5.0 152 45.0 42.5 12.5 240 38 39.5 22.5

35.0 62.5 2.5 153 41.5 48.5 10.0 241 37 43.0 20.0

0.0 100.0 0.0 154 36.5 56.0 7.5 242 35 47.5 17.5

155 30.0 65.0 5.0 243 32.5 52.5 15.0

156 21.5 76.0 2.5 244 29 58.5 12.5

Curve 4 157 0.0 100.0 0.0 245 26 64.0 10.0

0.0 0.0 100.0 246 22.5 70.0 7.5

3.5 1.5 95.0 247 18 77.0 5.0

7.3 2.8 90.0 248 12 85.5 2.5

15.7 4.3 80.0 Curve 8 249 0 100.0 0.0

22.8 7.2 70.0 158 0.0 0.0 100.0

30.5 9.5 60.0 159 3.0 2.0 95.0

34.5 10.5 55.0 160 5.8 4.2 90.0 Curve 12

37.7 12.3 50.0 161 12.5 7.5 80.0 250 0 0.0 100.0

41.7 13.3 45.0 162 19.0 11.0 70.0 251 2 3.0 95.0

45.5 14.5 40.0 163 26.0 14.0 60.0 252 4.5 5.5 90.0

48.0 17.0 35.0 164 29.0 16.0 55.0 253 9.4 10.6 80.0

51.5 18.5 30.0 165 32.3 17.7 50.0 254 15 15.0 70.0

54.0 21.0 25.0 166 35.0 20.0 45.0 255 20 20.0 60.0

55.0 22.5 22.5 167 39.0 21.0 40.0 256 22.5 22.5 55.0

56.5 23.5 20.0 168 42.4 22.6 35.0 257 25.5 24.5 50.0

56.7 25.8 17.5 169 45.5 24.5 30.0 258 27.5 27.5 45.0

56.0 29.0 15.0 170 48.0 27.0 25.0 259 30 30.0 40.0

54.0 33.5 12.5 171 48.5 29.0 22.5 260 32 33.0 35.0

51.5 38.5 10.0 172 48.0 32.0 20.0 261 33.5 36.5 30.0

47.3 45.3 7.5 173 47.7 34.8 17.5 262 34 41.0 25.0

41.0 54.0 5.0 174 45.0 40.0 15.0 263 33.5 44.0 22.5

31.0 66.5 2.5 175 42.5 45.0 12.5 264 32 48.0 20.0 87 0.0 100.0 0.0 176 37.5 52.5 10.0 265 30.5 52.0 17.5

177 33.0 59.5 7.5 266 28 57.0 15.0

178 26.5 68.5 5.0 267 27 60.5 12.5

Curve 5 179 18.0 79.5 2.5 268 23 67.0 10.0

88 0.0 0.0 100.0 180 0.0 100.0 0.0 269 20 72.5 7.5

89 3.5 1.5 95.0 270 16 79.0 5.0

90 7.0 3.0 90.0 271 10 87.5 2.5

91 15.0 5.0 80.0 272 0 100.0 0.0

92 22.3 7.7 70.0

The mixtures were then transferred into closed containers and stored at 25 deg C for a period of two weeks. After two weeks the samples were investigated to observe the effect of the applied ultrasonic energy. Samples of prepared fuel blends were analysed for phase separation, and the proportions of homogenous mixtures that fit the binodal curve for sonicated and non- sonicated are given in below Table 8.

Table 8: Proportion of homogenous mixtures that fit the

binodal curve for sonicated and non-sonicated

Proportion in class

Sample No Proportion in class (%) Sample No

(%)

ethanol water petrol ethanol water petrol

Non-sonicated binodal curve Sonicated binodal curve

1 0 0 100 20 0.0 0.0 100.0

2 10 1.75 88.25 21 3.5 1.5 95.0

3 17 3 80 22 7.3 2.8 90.0

4 20 3.5 76.5 23 15.7 4.3 80.0

5 30 5 65 24 22.8 7.2 70.0

6 40 7 53 25 30.5 9.5 60.0

7 50 11 39 26 34.5 10.5 55.0

8 60.0 16.5 23.5 27 37.7 12.3 50.0

9 62.0 18.0 20.0 28 41.7 13.3 45.0

10 63.0 24.0 13.0 29 45.5 14.5 40.0 11 62.0 28.0 10.0 30 48.0 17.0 35.0

12 60.0 32.5 7.5 31 51.5 18.5 30.0

13 55.0 40.0 5.0 32 54.0 21.0 25.0

14 51.5 47.0 1.5 33 55.5 23.0 21.5

15 41.5 57.5 1.0 34 58.5 22.0 19.5

16 31.0 68.2 0.8 35 59.0 24.0 17.0

17 20.4 79.0 0.6 36 58.4 26.6 15.0

18 10.1 89.5 0.4 37 54.0 33.5 12.5

19 0.0 100.0 0.0 38 51.5 41.0 7.5

39 47.5 48.5 4.0

40 41.0 57.8 1.2

41 31.0 68.1 0.9

42 0.0 100.0 0.0

Figure 4 shows the binodal curves for a non-sonicated sample prepared by conventional mixing (top line) and homogenous sonicated fuel blend of ethanol, water and petrol at ca. 25 deg C (bottom line).

As can be seen from Figure 4, the ultrasonic energy blending process resulted in a shift of the points that were originally on the binodal curve of the triangular diagram, thus indicating that ultrasonic energy has an effect on the phase separation of the three components of the fuel blend.

The results obtained from this experiment clearly indicate that an ultrasonic energy blending process could be used in preparing homogenous ethanol- petrol fuel blends which contains previously unacceptable concentrations of water.