LU82566A1 - FUEL COMPOSITIONS AND PROCESS FOR PREPARING THE SAME - Google Patents

Description

i i- DESCRIPTIVE MEMORY filed in support of a

PATENT INVENTION APPLICATION

formed by the so-called Company: LAB0F1NA S.A.

for FUEL COMPOSITIONS AND PROCESS FOR PREPARING THEM Inventor: Monsieur André Lepain.

The present invention relates to a new fuel based on% light fuel oil intended for use in diesel engines or in heating boilers. In particular, the present invention relates to an emulsion of the water in oil type comprising in addition to light fuel oil, a lower alcohol, water and an emulsifying agent.

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For several years, a great deal of research has been carried out with a view to reducing oil consumption by using alternative fuels. This research was first directed to gasoline engines, or spark ignition engines, to find new types of fuels. They have shown that the most acceptable solution at present is mixtures of alcohol and petrol, since methanol or ethanol are miscible with petrol of certain proportions, and that the octane number of these alcohols is relatively high, around 87 to 90. However, in the presence of traces of water, a demixing of the alcohol-petrol mixture is observed if the volume of alcohol represents less than 10% of the mixture. This research has also shown that it is easy to envisage replacing petrol with an alcohol-petrol mixture; on the other hand, they revealed that it was not the same for the fuels fueling diesel engines. Indeed, it is well known that fuels for diesel engines must have a cetane number, that is to say their ability to self-ignite, of at least 26, to allow proper operation of the diesel engine. . The methanol cetane number is

• S

of 3 and that of ethanol of 8, whereas that of a light fuel generally varies between 34 and 55, which leaves only a small margin for preparing light fuel-alcohol mixtures, having a valid cetane number . However, in the case where the fuel based on light fuel oil is used to supply boilers, this cetane number no longer has any influence and therefore the proportion of alcohol can be increased in these mixtures. On the other hand, as methanol or ethanol is essentially immiscible with light fuel, this excludes the possibility of preparing light fuel-alcohol mixtures in advance. The only solution that has been suggested so far is a bimodal diesel engine power system, which requires mechanical modifications. These modifications * however have various significant drawbacks, such as the need to provide two separate tanks, a double supply circuit and an alcohol metering system.

The object of the present invention is to avoid all these drawbacks.

It has fed a new fuel. nnnr Di asp motor! nti nonr ebatiflière.

- 3 - based on light fuel oil, alcohol, water and an emulsifier which is in the form of a stable water-in-oil emulsion.

The fuel composition for a diesel engine or for a boiler consisting of a water-in-oil type emulsion is characterized in that it comprises from 45 to 92% by volume of light fuel, from 5 to 45% by volume of a aqueous alcohol solution chosen from the group comprising methyl alcohol, ethyl alcohol and their mixtures, the percentage by volume of water in this solution 'being between 45.7 + 0.229 S and 74.3, where S is the percentage by volume of ethyl alcohol used, based on the total volume of alcohol, and from 3 to 10% by volume of an emulsifier chosen from the group comprising the mixtures of emulsifiers sorbitan monooleate-emulsifier non-ionic ethoxylated soluble in water, the HLB of the resulting emulsifier being between 5 and 7.

Indeed, the Applicant has now found a fuel composition for a diesel engine or for a boiler which comprises from 5 to 45% by volume of a mixture of alcohol and water.

Alcohol is understood to mean lower alcohols immiscible with light fuel, such as methanol and ethanol or their mixtures. Denatured alcohols containing up to 3% denaturant such as methyl ethyl ketone can also be used.

This new composition is in the form of a stable emulsion of the water in oil type, having a viscosity low enough to be used as fuel in diesel engines or in boilers.

To be able to use an emulsion of light fuel oil, alcohol and water as fuel for a diesel engine, it is not only necessary that this emulsion has a sufficient cetane index, although this can be remedied by adding an accelerator. such as isopropyl nitrate and the like, but above all x this emulsion must be extremely stable, so as to avoid demixing, in which case the water would end up in the bottom of the tank and risk being pumped out. first, which would have the effect of irreparably blocking the engine. When used as a boiler fuel only the last condition - 4 - is important.

By the term "stable emulsion" is meant an emulsion in which the water practically does not decant, for a period of at least 72 hours, but for which a ring of light fuel is allowed, provided that the light fuel decanted does not represent more than 3% by volume of light fuel oil present in the emulsio

The Applicant has now found that the stability of light fuel-alcohol-water emulsions depends on many factors, in particular the type and quantity of emulsifier, the HLB of the emulsifier, the respective proportions of alcohol and water. , the type of alcohol and the method of preparation of the emulsion.

In the case of use as a diesel engine fuel, the maximum amount of alcohol-water mixture is fixed for the sake of maintaining a sufficient cetane number. Although it is possible to use quantities of alcohol-water mixture * up to 45% by volume, it is however not advisable in this specific case to introduce more than 40% by volume. On the other hand, in the case of use as a fuel for a boiler, compositions containing 45% by volume of alcohol-water mixture can be used, the limiting factor here being the calorific value. On the other hand, for compositions containing less than 5% by volume of this mixture, the saving in fuel of the light fuel type is negligible and therefore such compositions are hardly of interest.

For emulsions containing at most 45% by volume of alcohol-water mixture, the Applicant has found that the emulsion formed is stable if the HLB of the emulsifier is between 5 and 7 and this regardless of the type of emulsifier 'used.

The type of emulsifier also plays a large role in the stability of the emulsion, and it is advantageous to choose it from the group comprising the sorbitan monooleate systems - non-ionic emulsifying agent, water-soluble ethoxylate.

As suitable examples of such emulsifier systems, mention may in particular be made of sorbitan monoleate - ethoxylated sorbitan monooleate having from 14 to 40 moles of ethylene oxide; sorbitan monooleate-sorbitan monolaurate i ............ - 5 - ethoxylated having from 11 to 40 moles of ethylene oxide; sorbitan monooleate - polyethylene glycol monooleate of molecular weight between 480 and 1200; sorbitan monooleate ethoxylated nonylphenol having 8 to 50 moles of ethylene oxide.

The other systems, not containing sorbitan monooleate, do not lead to stable emulsions, regardless of the HLB of the emulsifier used.

The desired HLB is obtained by varying the respective amounts of sorbitan monoleate and ethoxylated nonionic emulsifier. The different quantities to be used to obtain the desired HLB will be easily determined by those skilled in the art.

The stability of the emulsion also depends on the amount of emulsifier: This amount is at least 3% by volume, based on the volume of the emulsion. Amounts of emulsifier greater than 10% by volume do not bring a significant improvement in the stability of the emulsion.

Another important factor influencing the stability of the emulsion is the relative proportion of water in the alcohol-water mixture. We have found that the amount of water to be introduced into the alcohol-water mixture to obtain a stable emulsion depends on the type of alcohol used. Thus the Applicant has determined that in methanol-water mixtures, the amount of water must be between 45.7 and 74.3% by volume of the mixture, while in ethanol-water mixtures, this amount must be between 68.6 and 74.3% by volume of the mixture. Alcohol-water mixtures containing quantities of water outside the ranges defined above respectively for methanol-water and ethanol-water mixtures, do not make it possible to obtain stable emulsions, even if the quantity of emulsifier is considerably increased .

In the case of methanol-ethanol-water mixtures, it has been found that only certain mixtures make it possible to obtain a stable emulsion. When we represent such ternary mixtures on a triangular methanol, ethanol, water diagram, we notice that the appropriate ternary mixtures are located in a defined area Dar au auadrilaire ABCD whose noints A. B. C and D represent - 6 -

A simple way to determine the minimum and maximum quantities of water to form the emulsion when determining the quantities of alcohols to be used, is given by the following equation:

45.7 + 0.229 S

in which S represents the percentage by volume of ethanol calculated on the volume of total alcohol. The maximum quantity being in all cases 74.3% by volume.

On the other hand, the Applicant has also unexpectedly found that the mode of preparation of the emulsion has a preponderant influence on the stability of the latter.

The process for preparing the emulsion of the present invention consists in first preparing in a suitable container a mixture of light fuel oil and emulsifier, then in another container preparing the alcohol-water mixture and adding while stirring using a conventional agitator, the alcohol-water mixture in the light fuel mixture ~ emulsifier. Other preparation methods lead either to the formation of unstable emulsions, such as for example if the light fuel-emulsifier mixture is added to the alcohol-water mixture, or to the use of high energy agitator of the type ultraturax to obtain a stable emulsion, for example if water and alcohol are added separately to the light fuel-emulsifier mixture.

The use of such stirrers is very delicate, because the temperature increases very strongly during mixing, which can influence the stability of the emulsifier but also cause the evaporation of part of the alcohol.

The following examples are given to better illustrate the present invention, but without limiting its scope.

Example 1 * The following emulsions were prepared by mixing in a container 61 cc of light fuel oil and 4 cc of different emulsifiers each covering a range of HLBs ranging from 4.3 to 8.5. On the other hand, a mixture was prepared containing 15 cc of methanol and 20 cc of water.

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Then, with stirring, the methanol-water mixture was introduced into the light fuel-emulsifier mixture. The emulsion differences obtained from the stability point of view were tested.

The emulsifier mixtures used were as follows: A: Sorbitan monooleate - Ethoxylated sorbitan monooleate (20 moles of ethylene oxide) B: Sorbitan monooleate - Ethoxylated sorbitan monolaurate (20 moles of ethylene oxide) G: Sorbitan monooleate - polyethylene glycol monooleate (PM 600) D: Sorbitan monooleate - ethoxylated nonylphenol (15 moles of ethylene oxide).

The different HLBs were obtained by varying the amount of water-soluble ethoxylated nonionic emulsifier.

The results are shown in Table 1.

Stability was measured 96 hours after preparing the emulsion. TABLE 1

Emulsifier / HLB 4.3 5 5.5 6 6.5 7 7.5 8 8.5 A + ++ ++ ++ ++ ++ + ”“ B + ++ ++ ++ ++ ++ + - - C +++++++++++++ - D + ++ ++ ++ ++ ++ + - - ++: stable +: partial demixion - î total demixion For comparison, we tested the following mixtures of emulsifiers under the same conditions: E: Polyethylene glycol monooleate (PM200) - Polyethylene glycol monooleate (PM600) F; Ethoxylated fatty alcohol (2 moles of ethylene oxide) - Ethoxylated fatty alcohol (5 moles of ethylene oxide)

With none of these emulsifiers was it possible to obtain an emulsion i - 8 -

Example 2

Several emulsions having different emulsifier contents were prepared according to the method described in Example 1. These emulsions were tested from the stability point of view, in a restricted range of HLBs between 5 and 7.

The total volume of each emulsion was 100 cc and each of them contained 15 cc of methanol and 20 cc of water. The volume of the emulsifier varied between 1 and 10 cc and the volume of light fuel oil varied between 55 and 64 cc.

The emulsion prepared with the emulsifier A described in Example 1 had the following properties indicated in Table 2.

TABLE 2 HLB /% Emulsifier 1 2 3 4 5 6 8 10 5 "++ ++ ++ ++ ++ ++ 5.5 - - ++ ++ ++ ++ ++ ++ 6 6" * ++ ++ ++ ++ ++ ++ 6.5 - ++++++++++ ++ ++ 7 - ++++++++ ++ ++ ++: stable after 96 hours - î demixion before 96 hours

The emulsions prepared with the emulsifiers B and C described in Example 1 have the same characteristics.

Example 3

An emulsion of light fuel-methanol ~ water was prepared by first mixing in a container 61 cc of light fuel and 4 cc of the mixture of emulsifiers sorbitan monooleate - ethoxylated sorbitan monooleate (20 moles of ethylene oxide ).

In another container, 15 cc of methanol and 20 cc of water were mixed. This latter mixture was then poured, while stirring with a conventional agitator, into the container containing the light fuel-emulsifier mixture, to form an emulsion in which the emulsifier has an HLB of 6. This emulsion was still stable after 96 hours.

- 9 - adding, while stirring with the same stirrer, successively the methanol and the water to the light fuel-emulsifier mixture.

After 48 hours, we observed a partial demixion and after 72 hours! a total demixion.

However, we have managed to obtain a stable emulsion by successively adding methanol and water, but using a high energy stirrer of the ultraturax type, but limiting the temperature increase during mixing by stopping the agitation as soon as the emulsion begins to form.

The emulsion described above was also prepared by adding the light fuel-emulsifier mixture to the methanol-water mixture. Less than 24 hours later, there was complete separation.

i; Example 4!

The following emulsions were prepared according to the method described in Example 1.

61 cc of light fuel oil were thus mixed with 4 cc of the sorbitan monooleate-ethoxylated sorbitan monooleate mixture (20 moles of ethylene oxide) and mixtures containing 15 cc of methanol and 20 cc of water were added to it. of different hardness. ''

The HLB of the different emulsions was 6.

The stability of the emulsions obtained is indicated in Table 3.

TABLE 3

Hardness: 0 French Water 5 ° 10 ° 15 ° 20 ° 25 ° 40 ° distilled

Stability ++ ++ ++ ++ ++ ++ ++ ++: stable after 96 hours Example 5

The stability of different emulsions having variable volumes of methanol and of water was tested, for the same total volume of the methanol-water mixture, the HLB of the various emulsions which were prepared was 6.

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The volumes of the various components of the emulsions as well as their stability are indicated in Table 4. The volumes are expressed in ec.

TABLE 4 light fuel 61 61 61 61 61 61 61 61 57

Emulsifier A

described in example 1444444448 Methanol 7 8 9 16 17 18 19 20 20

Water 28 27 26 19 18 17 16 15 15

Stability - - ++ ++ ++ ++ ++ - -

Stability: ++: stable after 96 hours -: separation before 96 hours

Example 6

An emulsion was prepared according to the method described in Example 1 from 61 cc of light fuel, 4 cc of the emulsifier A described in Example 1, 15 cc of methanol and 20 cc of water.

The HLB of the emulsion obtained was 6.

This emulsion was placed in a refrigerated enclosure at a temperature of -20 ° C.

After 96 hours, the emulsion was still very stable.

Example 7

Emulsions were prepared according to the method described in Example 1, but using different proportions of light fuel oil and methanol-water mixture. The amount of water in the methanol-water mixture was 57.1% by volume.

The stability of these emulsions was tested and the results are shown in Table 5.

> - 11 - TABLE 5

Light fuel 91 81 71 51

Emulsifier A described in example 1 4444 Aanol / water mixture 5 15 25 45 HLB 6 6 6 6

Stability ++ ++ ++ ++

Stability: ++: stable after 96 hours Example 8

The following emulsions were prepared by mixing in a container 61 cc of light fuel and 4 cc of different emulsifier systems each covering a range of HLB from 4.3 to 8.5. On the other hand, a mixture * was prepared containing 25 cc of water and 10 cc of ethanol.

The ethanol-water mixture was then introduced, with stirring, into the light fuel-emulsifier mixture. The different emulsions obtained were tested from the stability point of view.

The mixtures of emulsifiers used are the mixtures A to D described in Example 1.

The results obtained are shown in Table 6.

Stability was measured 96 hours after preparing the emulsion. TABLE 6

Emulsifier / HLB 4.3 5 5.5 6 6.5 7 7.5 8 8.5 A - ++ ++ ++ ++ ++ - - - B - ++ ++ ++ ++ ++ - - - C - ++++++++++ --- D - ++ ++ ++ ++ ++ - - -. ": demixing before 96 hours ++: stable after 96 hours.

By way of comparison, emulsions were prepared with the mixtures of emulsifiers E and F.

Example 9 - 12 -

Several emulsions having different emulsifier contents were prepared according to the method described in Example 8. These emulsions were tested from the stability point of view, in a restricted range of HLBs between 5 and 7.

The total volume of each emulsion was 100 cc and each of them contained 25 cc of water and 10 cc of ethanol. The volume of the emulsifier varied between 1 and 10 cc and the volume of light fuel oil varied between 55 and 64 cc.

The emulsion prepared with the emulsifier A described in Example 1 had the following properties indicated in Table 7.

TABLE 7 HLB /% emulsifier 1% 2% 3% 4% 5% 6% 8% 10% * 5.0 - - ++ ++ ++ ++ ++ ++ 5.5 - - ++ ++ + + ++ ++ ++ 6 - - ++ ++ ++ ++ ++ ++ 7 - ++++++ ++ ++ ++ ++; stable after 96 hours -: total demixing before 96 hours

Example 10

The stability of different emulsions having variable volumes of ethanol and water was tested for the same total volume of the ethanol-water mixture. The HLB of the emulsifier used was 7.

The volumes of the various components of the emulsions as well as the stability of the latter are indicated in Table 8. The volumes are expressed in cc.

TABLE 8 • Light fuel 61 61 61 61 61 61 61 61 57 57

Emulsifier A

described in example 14444444488 Ethanol 5 6 7 8 9 10 11 12 13 13

Water 30 29 28 27 26 25 24 23 22 22

Example 11 - 13 -

Emulsions were prepared according to the method described in Example 8, but using different proportions of light fuel oil and ethanol-water mixture.

The amount of water in the ethanol-water mixture was 71% by volume.

The stability of these emulsions was tested and the results are shown in Table 9.

TABLE 9

Light fuel 91 81 71 51

Emulsifier A described in example 1 4 4 4 4 Ethanol-water mixture 5 15 25 45 HLB 7 7 7 7 *

Stability ++ ++ ++ ++

Stability: ++: stable after 96 hours.

Example 12

The stability of different emulsions prepared with ternary methanol-ethanol-water mixtures was tested.

Among the emulsions thus tested, several were prepared from methanol-ethanol-water ternary mixtures whose representative point on a triangular diagram is outside the quadrilateral ABCD formed by connecting the representative points of binary mixtures having the minimum and maximum contents in water. The volumes of the various components of the emulsions as well as the stability of the latter are indicated in Table 10. The volumes are expressed in cc.

Claims (3)

1. Fuel composition for diesel engine or for solid boiler | y in an emulsion of the water in oil type, characterized in that it comprises ί from 45 to 92% by volume of light fuel oil, from 5 to 45% by volume of an aqueous solution ί alcohol chosen in the group comprising methyl alcohol, ethyl alcohol and mixtures thereof, the percentage by volume of water in this solution> being between 45.7 + 0.229 S and 74.3, where S is the percentage by volume of ethyl alcohol used, based on the total volume of alcohol, and from 3 to 10% by volume of an emulsifier, chosen from the group comprising mixtures of emulsifiers sorbitan monooleate-soluble non-ionic ethoxylated emulsifier I - '"- 15 - 2. Composition according to claim 1, characterized in that the water-soluble ethoxylated nonionic emulsifier is chosen from the group preferably comprising the ethoxylated sorbitan monooleate having from 14 to 40 moles of ethylene oxide, the monolaurate of ethoxylated sorbitan having from 11 to 40 moles of ethylene oxide, the polyethylene glycol monooleate having a molecular weight of between 480 and 1200, the ethoxylated nonylphenol having from 8 to 50 moles of ethylene oxide. 3. A method of preparing a fuel composition for a diesel engine or for a boiler described in claims 1 and 2, characterized in that the light fuel and the emulsifier are mixed in a suitable container, and mixed in another container of alcohol and water, and which is introduced while stirring with a usual agitator the alcohol-water mixture in the light fuel% emulsifier mixture. i! "