NL8006041A - DIESEL FUEL MATERIALS AND METHOD FOR PREPARING THEREOF. - Google Patents

Description

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Diesel fuel materials and method for their preparation.

The invention relates to new diesel fuel materials and to a process for their preparation. More particularly, the invention relates to water-in-oil emulsions containing a diesel fuel, an alcohol, water and an emulsifying agent.

The use of replacement fuels to reduce crude oil consumption has become of significant importance in recent years. More specifically, research in this field is directed to gasoline or spark plug ignition engines. A more attractive solution consists of using mixtures of gasoline and alcohols; methanol and ethanol can be mixed with gasoline in all proportions and they have a large octane number (about 87 to 90).

However, the inclusion of alcohols in diesel fuels gives rise to some difficulties. It is known that trouble-free running of diesel engines (or spontaneous ignition engines) requires the use of 20 fuels with a cetane number of at least 26. But the cetane numbers of methanol and ethanol are small (resp.

3 and 8) and the cetane number of a diesel fuel, more particularly gas oil and light fuel oil is between 34 and 55. Therefore, the range of mixtures containing a diesel fuel and alcohol and showing a suitable cetane number is relatively small. In addition, methanol and ethanol are practically immiscible with the diesel fuel and mixtures of these components cannot be prepared in advance. The only solution that has been proposed is to use a bimodal feeding system. Such a system requires mechanical modifications, i.e. two tanks, an alcohol warning device, etc.

It is an object of the present invention to provide diesel fuel materials that overcome these drawbacks. Another object is to provide stable replacement fuels with a suitable cetane number.

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Yet another object is to provide water-in-oil emulsions containing a diesel fuel and an alcohol. It is also an object of the invention to provide a method for preparing these emulsions.

The flammable water-in-oil emulsions of the present invention include: 97 to 90 vol. % of a mixture containing a major part of a diesel fuel which is gas oil and / or light fuel oil, and a smaller amount of an aqueous solution of methanol and / or ethanol, and 3 to 10 vol. % of an emulsifying mixture containing sorbitan monooleate and a water-soluble, nonionic, ethoxylated surfactant.

In accordance with an embodiment of this invention, in which gas oil is used as the diesel fuel, the emulsion contains 55 to 92 vol. % gas oil, 5 to 35 vol. % of an aqueous solution of alcohol, the volume percentage of water in the solution being between 43 + 0.20 S and 74, where S represents the volume percentage of ethanol, based on the total volume of alcohol, and 3 to 10 vol. % emulsifying mixture.

In another embodiment, using light fuel oil as the diesel fuel, the emulsion comprises 45 to 92 vol. % light fuel oil, 5 to 45 25 vol. % of an aqueous solution of alcohol, where the volume percentage of water in the solution is between 45.7 + 0.229 S and 74.3, where S represents the volume percentage of ethanol, based on the total volume of alcohol, and 3 to 10 vol ..% emulsifying mixture.

The alcohol is preferably methanol or ethanol or mixtures thereof. These alcohols may contain a small amount of another low molecular weight aliphatic alcohol or a denaturing agent such as methyl ethyl ketone. Therefore, denatured alcohols, generally containing up to 3% denaturant, can be used in the materials of the invention.

These new materials are stable water-in-oil emulsions, which have a low viscosity and a suitable cetane number. Therefore, they can be used as replacement 40 fuels for diesel engines and for heating purposes 8 0 06 0 4 1 Ψ t - 3 -. In addition, they are stable and do not give rise to unraveling and settling of water at the bottom of the tanks; settling of water is a serious drawback if the water is first injected into the motor or the burner and would disable it. The term "stable emulsion" means that practically no segregation occurs during a period of at least 72 hours; however, a ring of diesel fuel may appear to the extent that the amount of segregated fuel does not exceed 10 3 vol. % of the fuel present in the emulsion.

In the case of demixing, the emulsion is easily restored by stirring.

The stability of the emulsions of this invention depends on many factors such as the type of diesel fuel, nature and amount of emulsifier, HLB (hydrophilic-lipophilic equilibrium) of the emulsifier mixture, the respective amounts of alcohol and water, type of alcohol, method of preparation .

When the emulsion is used to power diesel engines, the upper amount of aqueous solution of alcohol in the emulsion is determined by considering the cetane number. Amounts of aqueous solution of up to 45 vol. % can be used, but in general are emulsions, which are not more than 40 vol. % 25 aqueous solution of alcohol, more suitable when the diesel fuel is light fuel oil. When the emulsion is prepared from gas oil, the amount of aqueous alcohol solution is generally 35 vol. % not to be exceeded. When the emulsions are used for heating purposes, the calorific value is the main limiting factor and emulsions which are at most 45 vol. % aqueous solution of alcohol can be used. On the other hand, emulsions with an aqueous alcohol content are less than 35 vol. % not very attractive, because the fuel cleaning is negligible.

The HLB of the emulsifying mixture also plays a role with regard to the emulsion stability. Preferably, the HLB of the emulsifying mixture is at least 5, 40 but generally does not exceed the value of 8 0 06 0 4 1 - 4 - about 7 when the fuel to be emulsified is light fuel oil, and not even the value of 6.5 in the case of gas oil. (Gasoil). The type of emulsifying mixture is further also a factor and the mixture preferably contains sorbitan 5-oleate together with a water-soluble nonionic ethoxylated surfactant. Illustrative surfactants include ethoxylated sorbitan monooleate containing up to 20 to 40 moles of ethylene oxide (or EO); ethoxylated sorbitan monolaurate with 11-40 E 0; ethoxy-10-taught nonylphenol with 8-50 EO; ethoxylated alcohols of fats, with 6-50 EO; monooleate of polyethylene glycol. with a mole wt. between about 480 and 1200. The choice of the surfactant depends on some factors such as availability, price and effectiveness. The emulsion stability also depends on the type of fuel to be emulsified; for example, emulsions prepared from gas oil are more stable than similar emulsions prepared from light fuel oil when ethoxylated fat alcohols are used as surfactants.

The required HLB can be achieved by varying the respective amounts of sorbitan monooleate and surfactant. The amounts to be used will be readily determined by one skilled in the art.

The emulsion stability also depends on the percentage of water in the aqueous alcohol solution. This percentage varies according to the type of alcohol (methanol, ethanol or mixtures thereof) and the type of fuel to be emulsified. For the preparation of light fuel oil emulsions, the volume percentage of water in the aqueous solution is generally between 45.7 + 0.229 S and 74.3, where S represents the volume percentage of ethanol based on total volume of alcohol. For gas oil-based emulsions, the percentage by volume of water in the aqueous solution is generally between 43 + 0.20 S and 74. Aqueous solutions of alcohol containing amounts of water outside these limits are generally less suitable for preparing 40 stable emulsions.

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It has been found that the method used for preparing the emulsions according to the invention exerts an influence on the emulsion stability. According to another embodiment of the present invention, the emulsions are prepared using a method in which i) a first mixture of diesel fuel and emulsifier mixture is prepared; ii) prepare an aqueous solution of alcohol; and iii) adding the aqueous solution to the first mixture while stirring.

Other methods of preparation present some difficulties. For example, the addition of the first mixture to the aqueous alcohol solution results in less stable emulsions. The addition of separate streams of water and alcohol to the first mixture requires the use of a high shear agitator, which induces an A increase in the temperature of the mixture and some evaporation of the alcohol.

In order to more fully illustrate the invention, the following nonlimiting examples are shown.

EXAMPLE I

Different emulsions were prepared by adding an aqueous solution containing 15 cm 3 of methanol 3 3 and 20 cm of water to a mixture containing 61 cm of light fuel oil and 4 cm of emulsifying mixture.

The emulsifying mixtures were as follows: A) sorbitan monooleate + ethoxylated sorbitan monooleate 30 (20 EO) B) sorbitan monooleate + ethoxylated sorbitan monolaurate (20 EO) C) sorbitan monooleate + monooleate of polyethylene glycol (600) ethylphenol + ethylphenol + ethylphenol + ethylphenol ).

The HLB of these mixtures were between 4.3 and 8.5.

These different HLB. were obtained by varying the respective amounts of the components of these mixtures.

The stability of the obtained mixtures was determined 8 0 06 0 4 1 - 6 - 96 hours after preparation thereof. The results are shown in Table A below.

TABLE A

5 SngÜef '4'3 5 5'5 6 6'5 7 7'5 8 8'5 A + ++ ++ ++ ++ Ή- + - - B +++++++++++ + - C + ++++++++++ + - D +++++++++++ + - 10 (++: stable? +: Partial demixing; -: total demixing) For comparison, the following emulsifying mixtures were used: X: Monooleate of polyethylene glycol (mol wt. 200) + Monooleate of polyethylene glycol (mol wt. 600) Y: ethoxylated alcohol of fat (2 E 0) 15 + ethoxylated alcohol of fat (5 E 0) .

Different mixtures in which the respective amounts of surfactants were adjusted to cover a wide range of HLB were prepared. Emulsions were prepared using these mixtures, but they were not stable.

EXAMPLE II

The procedure described in Example I was repeated to prepare emulsions with different levels of emulsifying mixtures and different HLB.

O

The total volume of each 100 cm emulsion and materials were as follows: 3 methanol: 15 cm 3 water: 20 cm emulsifying mixture: 1 to 10 cmJ (mixture A of Example I) light.

fuel oil: 55 to 64 cm.

The results of the stability tests were as follows: (Table B) 8 0 06 0 4 1

f I

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TABLE B

HLB emulsifying mixture (% by volume) 1 234567 8 5 - - ++++++ ++ ++ ++ 5 5/5 - - ++++++ ++ ++ ++ 6 - - ++ ++ ++ ++ ++ ++ 6,5 - - ++ ++ ++ ++ ++ ++ 7 - - ++ ++ ++ ++ ++ ++ 10 (++: stable after 96 hours; -: segregation).

The same results were obtained using the emulsifiers B and C described in Example I.

EXAMPLE III

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To a stirred mixture of 61 cm light fuel oil and 4 cm emulsifying mixture A (HLB = 6), an aqueous 3 solution containing 15 cm methanol and 20 cm water was added.

The resulting emulsion was stable after 96 hours.

Another portion of this emulsion was cooled at -20 ° C for 96 hours; it remained stable.

By comparison, the same amounts of components were used, but other procedures were followed: a) Separate streams of methanol and water were added to the stirred mixture / fuel and emulsifying mixture: total separation after 72 hours.

b) a mixture of fuel and emulsifier was added to the stirred aqueous solution of methanol: total separation after 24 hours.

EXAMPLE IV

Different emulsions were prepared with different amounts of methanol and water, but the total volume of methanol + water was the same in each emulsion.

The emulsifying mixture (mixture A of example I) had an HLB of 6.

The materials (in vol.%) Of the emulsions and the 8 0 06 0 4 1 - 8 results of the stability test are shown in Table C.

TABLE C

light fuel oil 61 61 61 61 61 61 61 61 57 5 emulsifying mixture 444444448 methanol 7 8 9 16 17 18 19 20 20 water 28 27 26 19 18 17 16 15 15 stability - - ++ ++ ++ ++ ++ - -

EXAMPLE V

Different emulsions were prepared with different amounts of light fuel oil. For each emulsion, the amount of water in the aqueous solution of methanol was 57.1 vol. %.

The emulsifying mixture (mixture A of example I) had an HLB of 6.

The materials (in vol.%) Of the emulsions and the results of the stability tests are shown in Table D.

TABLE D

20 light fuel oil 91 81 71 51 emulsifying mixture 4444 methanol + water 5 15 25 45 stability ++ ++ ++ ++

EXAMPLE VI

Different mixtures were prepared from 61 cm 3 of light fuel oil and 4 cm from each of the emulsifying mixtures A to D, as described in Example I. The HLB of these mixtures ranged from 4.3 to 8.5.

An aqueous solution of ethanol was prepared from 25 vol. % water and 10 vol. % ethanol.

The method described in Example I was used to prepare the emulsions; the total volume 3 of each emulsion was 100 cm.

The results of the stability tests (after 96 hours) 35 are shown in Table E.

8006041 Γ * - 9 - TABLE Ε _ _

Zglef '4'3 5 5'5 6 6'5 7 7'5 3 8'5 A - ++++++++++ --- 5 Β - ++++++++++ - - C - ++++++++++ --- D - ++++++++++ --- ---

EXAMPLE VII

Different emulsions were prepared from light fuel oil, emulsifying mixture A from example I (HLB: from 5 to 7), water and ethanol. The total volume of j3 each emulsion was 100 cm. The emulsions contain 25 cm 3 of water, 10 cm of ethanol, 1 to 10 cm of emulsifier and 3 resp. 54 to 64 cm of fuel.

The results relative to stability are shown in Table F.

TABLE F

HLB emulsifying mixture (vol.%) 1 2 3 4 5 6 8 10 20 5 - - ++ ++ ++ ++ ++ ++ 5.5 - ++ ++++++++ ++ 6 ~ “ ++ ++ ++ ++ ++ ++ 7 - ++ ++++++ ++ ++

EXAMPLE VIII

Different emulsions were prepared from light fuel oil, emulsifying mixture A from example I (HLB = 7) and an aqueous solution of ethanol (vol% water: 73.4).

The materials (vol.%) And stability test results are shown in Table G.

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TABLE G

light fuel oil 91 81 71 51 emulsifying mixture 4444 aqueous solution of 5 ethanol 5 15 25 45 stability ++ ++ ++ ++

EXAMPLE IX

Different emulsions were prepared using aqueous solutions containing methanol and ethanol.

The respective volumes of the components and the results of the stability tests are shown in Table H.

TABLE H

Experiment 12345678 15 dust oil ^^ "61 51 61 61 61 61 61 61 emulsifying mixture A 44444444 (HLB = 7) 20 methanol 16.6 14.0 14.0 10.5 7 1.75 1.75 3.5 ethanol 0, 9 1.75 3.5 1.75 3.5 7 8.75 10.5 water 17.5 19.25 17.5 22.75 24.5 26.25 24.5 21 stability ++ ++ - ++ ++ ++ ++

Experiments 3 and 8 are comparison experiments. The amount of water is less than the required minimum amount. In experiment 3, the amount of water in the aqueous alcohol solution is 50% and the minimum should be 45.7 + (0.229 x 20) or 50.28%. In experiment 8, the amount of water in the aqueous solution of alcohols is 60% and the minimum should be 45.7 + (0.229 x 75) or 62.87%.

EXAMPLE X

Different emulsions were prepared. For each 3 3 emulsion, a mixture of 36 cm methanol and 16 cm 40 water was added with stirring to a mixture containing 64 cm 8 0 06 0 4 1 2 1 3-11 gas oil and 4 cm emulsifying mixture.

The emulsifying mixtures used were Mixture A to D of Example I and Mixture E, which contained sorbitan monooleate and ethoxylated fat alcohol (9E0). The HLB 5 of these mixtures (from 5 to 12) were obtained by varying respective amounts of components.

The results are shown in Table J.

TABLE J

emulsifying HLB

10 mixture 5 5.5 6 6.5 7 8 10 12 A ++ ++ ++ ++ + - - - B +++++++++ - - C ++ ++ ++ ++ + - - - D +++++++++ - - 15 E ++ ++ ++ ++ + - - - (++: stable after 96 hours; +: partial separation; -: total separation)

By way of comparison, the following emulsifying mixtures were used to prepare similar emulsions.

F; sorbitan monooleate + polyethylene glycol monooleate (mole wt: 300) (insoluble in water) G; sorbitan monooleate + ethoxylated nonylphenol (4 E 0) (insoluble) 25 H; sorbitan monooleate + ethoxylated alcohol from fat (3 E 0) (insoluble) I; sorbitan monolaurate + ethoxylated sorbitan monolaurate (20 E 0) (soluble) J: monooleate of polyethylene glycol (mol wt. 200) + 30 monooleate of polyethylene glycol (mol wt. 600) (soluble) K ethoxylated nonylphenol (4 E 0) + ethoxylated nonylphenol (15 E 0) L: ethoxylated fat alcohol (3 E 0) + ethoxylated fat alcohol (9 E 0).

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The emulsions prepared using these emulsifying mixtures were not stable.

EXAMPLE XI

An emulsion was prepared from gas oil (64% by volume), emulsifying mixture A of Example I (4% by volume), methanol (16% by volume) and water (16% by volume).

The cetane number of the emulsion was 26.

The emulsion was used to power a diesel engine.

A road test (80 km) was performed and the emulsion consumption was 48.3 liters or a gas oil consumption of 30.9 liters. The same test was performed but powered by the diesel engine with gas oil: consumption was 39.3 liters.

EXAMPLE XII

Emulsion containing various amounts of emulsifying mixture (mixture A; HLB ranging from 5.5 to 6.5) was prepared.

3

Each emulsion had a total volume of 100 cm.

3 ·? Hi} contained 22.5 cm of water and 12.5 cm 3 of ethanol. The amount of emulsifier varied between 1 and 10 cm and the amount of gas oil varied between 55 and 64 cm.

The results of the stability tests are shown in Table K.

25 TABLE K

! hlB emulsifying mixture (% by volume) 1 234568 10 5.5 - - ++++++++++ ++ 6 - ++++++ ++ ++ ++ 30 6.5 - - + + ++ ++ ++ ++ ++ - conclusions - 8 0 06 0 4 1

Claims (8)

Water-in-oil type diesel fuel emulsions, characterized by: 97 to 90 vol. % of a mixture containing a predominant amount of conventional diesel fuel and a minority amount of at least 5 vol. %, based on the volume of the emulsion, of an aqueous solution of methanol and / or ethanol, and 3 to 10 vol. % of an emulsifying mixture of sorbitan monooleate and water-soluble ethoxylated nonionic surfactant. Diesel fuel emulsions according to claim 1, characterized by 55 to 92 vol. % gas oil, 5 to 35 vol. % aqueous solution of methanol and / or ethanol, the volume percentage of water in the solution being between 43 + 0.20 S and 74, where S represents the 15 volume percentage of ethanol, based on the total volume of alcohol, and 3 to 10 full. % emulsifying mixture with an HLB between 5 and 6.5. Diesel fuel emulsions according to claim 2, characterized in that the surfactant 20 is an ethoxylated sorbitan monooleate with 20-40 moles ethylene oxide, an ethoxylated sorbitan monolaurate with 11-40 moles ethylene oxide, an ethoxylated nonyl phenol with 8-50 moles ethylene oxide, and ethoxylated alcohol of fat with 6-50 moles of ethylene oxide and / or monooleate of polyethylene glycol with a mole wt. between 480 and 1200. Diesel fuel emulsions according to claim 1, characterized by 45 to 92 vol. % light fuel oil, 5 to 45 vol. % aqueous solution of methanol and / or ethanol, the volume percentage in the solution being between 45.7 + 0.229 S and 74.3, where S represents the volume percentage of ethanol, based on the total volume of alcohol and 3 to 10 vol . % emulsifier mixture with an HLB between 5 and 7. 8 0 06 0 4 1 - 14 - Diesel fuel emulsions according to claim 4, characterized in that the surfactant is an ethoxylated sorbitan monooleate with 20-40 moles ethylene oxide, an ethoxylated sorbitan monolaurate 5 with 11-40 moles ethylene oxide, an ethoxylated nonyl phenol with 8-50 moles ethylene oxide and / or a monooleate of polyethylene glycol with a mole wt. is between 480 and 1200. 6. Process for preparing emulsions according to one or more of claims 1 to 4, characterized in that the aqueous solution of alcohol is added with stirring to a mixture of fuel and emulsifying mixture. 7. Method and materials, as described or contained in the description and / or the examples. 8 0 06 0 4 1