LU81921A1 - FUEL COMPOSITIONS FOR A DIESEL ENGINE AND PROCESS FOR PREPARING THE SAME - Google Patents

Description

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^ DESCRIPTIVE MEMORY

filed in support of a

PATENT INVENTION APPLICATION

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

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

The present invention relates to a new diesel-based fuel for vehicles with a diesel engine. In particular, the present * ", invention relates to an emulsion of the water-in-oil type comprising, in addition to gas oil, an alcohol, water and an emulsifying agent.

For several years, a great deal of research has been done to reduce the consumption of petroleum 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 in certain proportions, and that the octane number of these alcohols is relatively high, around 87 to 90. However, the incorporation of alcohol into the fuels fueling diesel engines presents many problems. Indeed, it is well known that fuels for diesel engines must have a cetane number, that is to say their ability to self-declare, of at least 26, to allow proper operation of the diesel engine. However, the methanol cetane index -v> is 3 and that of ethanol 8, whereas that of a diesel generally varies between 34 and 55, which leaves only a small margin for preparing mixtures. diesel-alcohol with a valid cetane number. In addition, methanol or ethanol is essentially immiscible with diesel, which excludes the possibility of preparing diesel-alcohol mixtures in advance. The only solution that has been suggested so far is a bimodal engine power system, which requires mechanical modifications. However, these modifications have various non-negligible drawbacks, such as the need to provide two separate tanks, a double supply circuit, a methanol metering system.

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

It relates to a new diesel engine fuel based on diesel, alcohol, water and an emulsifier mixture which is in the form of a stable emulsion of the water in oil type.

* * The fuel composition for a diesel engine consisting of a water-in-oil type emulsion is characterized in that it comprises from 55 to 92% by volume of diesel, from 5 to 35% by volume of an aqueous solution of alcohol chosen from the group comprising methyl alcohol. ethyl alcohol and their '- 3 - 43 + 0.20 S and 74 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 a mixture emulsifier of sorbitan monol ^ a and non-ionic ethoxylated water-soluble emulsifier, the hydrophilic-lipophilic index of the emulsifier mixture being between 5 and 6.5.

The fuel composition for diesel engine of the invention comprises from 5 to 35% by volume of a mixture of alcohol and water. Alcohol is understood to mean lower aliphatic alcohols immiscible with diesel, such as methanol and ethanol or their mixtures.

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. In order to be able to use a diesel, alcohol and water emulsion as a fuel for a diesel engine, this emulsion must not only have a sufficient cetane number, although this can be remedied by adding an accelerator. ignition like isopropyl nitrate and the like, but above all this emulsion must be stable, so as to avoid demixing, in which case the water would end up in the bottom of the tank and risk being pumped first, which would have the effect of irreparably blocking the engine. 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 gas oil is allowed, provided that the decanted gas oil does not represent not more than 3% by volume of the diesel oil present in the emulsion,

The Applicant has found that the stability of diesel-alcohol-water emulsions depends on many factors, such as in particular the type and quantity of emulsifier, of the hydrophilic-lipophilic index, hereinafter called HLB, of the emulsifier, respective proportions of alcohol and water, type of alcohol and method of preparation of the emulsion.

The maximum quantity of alcohol-water mixture is fixed for the sake of ”. - 4 - recommended to use emulsions containing more than 35% by volume of the alcohol-water mixture. In addition, for compositions containing less than 5% by volume of this mixture, IV fuel economy of the diesel type is negligible and therefore such compositions are of little interest.

For emulsions containing at most 35% by volume of alcohol-water mixture, the Applicant has found that the emulsion formed is stable if the HLB of the emulsifier mixture is between 5 and 6.5.

The type of emulsifier plays a large role in the stability of the emulsion, and it is advantageous to choose it from the group comprising mixtures of sorbitan monoleate and of non-ionic emulsifying agent ethoxylated soluble in water. suitable examples of such emulsifier mixtures that may be mentioned include: sorbitan monooleate and ethoxylated sorbitan monooleate having from 14 to 40 moles of ethylene oxide; sorbitan monooleate and ethoxylated sorbitan monolaurate having 11 to 40 moles of ethylene dioxide; sorbitan monooleate and polyethylene glycol monooleate of molecular weight between 480 and 1200; sorbitan monoleate and ethoxylated nonylphenol having 8 to 50 moles of ethylene oxide; sorbitan monooleate and ethoxylated fatty alcohol having from 6 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, water-soluble nonionic emulsifying agent. The different quantities to be used to obtain the HLB

%, desired will be readily determined by those skilled in the art.

The stability of the emulsion also depends on the amount of emulsifier. This quantity is at least 3% by volume, based on the volume of the emulsifier. Quantities of emulsifier greater than 10% by volume do not provide any improvement.

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 43 and 74% by volume of the mixture, while in ethanol-water mixtures, this amount must be between 63 and 74% 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 an area defined by the quadrilateral ABCD whose points A and B, on the one hand, G and D on the other hand, represent respectively the binary mixtures methanol-water and ethanol-water usable, with the minimum and maximum water contents. We therefore see that, in the ternary methanol-ethanol-water mixtures, the amount of water is between 43 + 0.2 S and 74, where S represents the percentage by volume of ethanol calculated on the volume of total alcohol .

On the other hand, the Applicant has also unexpectedly found that the method of preparation of the emulsion has a preponderant influence on the stability thereof, * A process for the preparation of the emulsion of the present invention consists in first preparing in a suitable container a mixture of diesel and emulsifier, then in another container preparing the alcohol-water mixture .1- h simιΐ · Λν ** λιι * · an aorîf-iinf à 1 * a-iAa d * iin ao-i t'ai * enr usual. the alcohol-water-emulsifier mixture in the alcohol-water mixture, an unstable emulsion is obtained. On the other hand, if water and alcohol are added separately to the diesel-emulsifier mixture, obtaining a stable emulsion requires the use of a high energy agitator of the ultraturax type. The use of such stirrers is very delicate, since the temperature increases sharply during mixing, which can influence the stability of the emulsion, but also cause the evaporation of part of the alcohol. Although this latter process makes it possible to obtain stable emulsions, the preferred method of preparation of the emulsion of the invention is the first described since it only requires the use of a conventional agitator.

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 64 cc of gas oil and 4 cc of different emulsifier mixes each covering a range of HLB from 5 to 15. On the other hand, a mixture containing 16 cc of methanol and 16 cc of water.

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

The mixtures of emulsifiers 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).

C: Sorbitan monooleate - polyethylene glycol monooleate (P.M. 600).

* D; Sorbitan monooleate - ethoxylated nonylphenol (15 moles ethylene oxide).

E: Sorbitan monooleate - oxyethylenated fatty alcohol (9 moles of ethylene oxide).

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

- 7 -

Stability was measured 96 hours after preparing the emulsion. Table 1% ________ _______ _ -------- J ï!

, Emulgator, HLB J Index

! j 5 5.5 6 6.5 7 8 10 12 15 j; a! +++++++++ - - - -; i B! ++++++ -H- + - - - - î! ! ! C +++++++++ - - - -.

• “·! D! -H- -H- ++ -H- + - -! ! ! !

I E d -H * ++ -H * -H · + - - - I

j _! _! _ ++: stable +; partial demixion: total demixion For comparison, the following emulsifier mixtures were tested under the same conditions: F: Sorbitan monooleate - polyethylene glycol monooleate (P.H. 300) (insoluble in water).

G: Sorbitan monooleate - nonylphenolethoxylated (4 moles ethylene oxide) (insoluble in water).

H; Sorbitan monooleate - ethoxylated fatty alcohol (3 moles ethylene oxide) (insoluble in water).

I: Sorbitan monolaurate - ethoxylated sorbitan monolaurate (20 moles ethylene oxide) (soluble in water).

J; Polyethylene glycol monooleate (P.M. 200) - polyethylene glycol monooleate (P.M. 600) (soluble in water).

‘K: Ethoxylated nonylphenol (4 moles ethylene oxide) - ethoxylated nonylphenol (15 moles ethylene oxide).

L; Ethoxylated fatty alcohol (3 moles ethylene oxide) - ethoxylated fatty alcohol (9 moles ethylene oxide).

- 8 -

With none of these emulsifiers, we managed to obtain a stable emulsion, whatever the HLB.

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 5.5 and 7.

The total volume of each emulsion was 100 cc and each of them contained 16 cc of methanol and 16 cc of water. The volume of emulsifier varied between 1 and 10 cc and the volume of diesel varied between 58 and 67 cc.

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

Table 2 j f 1 ", HLB * Mixing emulsifier (% by volume) j! r Ll Ll Ll 4 5% 6% 8% 10% j «· ·! 5.5! -H- -H- -H- -H- ++ 4+! 1! »J 6, - ++ ++ ++ ++ ++ ++ d! 6.5! 4+ ++ ++ -H- -h- -h-! (i t i 7 î ........; j_J_i -H-; stable after 96 hours ": total 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 diesel-methanol-water was prepared by mixing k • first in a container 64 cc of diesel and 4 cc of the emulsifier mixture of sorbitan monooleate and ethoxylated sorbitan monooleate (20 moles of ethylene oxide) .

In another container, 16 cc of methanol and 16 cc - 9 - were mixed.

of water. This latter mixture was then poured, with stirring with a usual agitator, into the container containing the gasoil-emulsifier mixture, to form an emulsion whose "emulsifier has an HLB of 6. This emulsion was still stable after 96 hours.

By way of comparison, the emulsion described above was prepared by adding, while stirring with the same stirrer, successively the methanol and the water to the gasoil-emulsifier mixture.

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

However, we managed to obtain a stable emulsion by successively adding methanol and water, but using a high-energy agitator of the ultraturax type, but limiting the temperature increase during mixing, stopping the agitation as soon as possible. that the emulsion is formed.

The emulsion described above was also prepared by adding the diesel-emulsifier mixture to the metharrbl-water mixture. Less than 24 hours later, there was complete demixing.

Example 4

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

64 cc of diesel fuel were thus mixed with 4 cc of the emulsifier mixture of sorbitan monooleate and ethoxylated sorbitan monooleate (20 moles of ethylene oxide) and mixtures containing 16 cc of methanol and 16 cc were added to it. of water of different hardness.

The HLB of the different emulsifier mixtures was 6.

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

Hardness (° French) Water 5 ° 10 ° 15 ° 20 ° 25 ° 40 ”distilled

Stability Ή * -H * ++ ++ 4+ ++ ++ - 10 -

Example 5 *

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

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

Table 4 123456789 10 11 12

Diesel 61 61 * 61 59 57 61 61 59 57 57 57 57

Emulsifier A4446844688 8 8 described in Example 1 Methanol 17.5 20 22.5 22.5 22.5 15 12.5 12.5 12.5 10 9 8 ". Water 17.5 15 12.5 12.5 12.5 20 22.5 22.5 22.5 25 26 27

Stability ++ -H- * # * * # -H * *** -H- -H- -H- -H- +

Stability: ++: stable after 96 hours * î 34% separation after 24 hours **: 30% separation after 24 hours ***: 14% separation after 24 hours +: 19% separation after 96 hours

In addition, the cetane numbers of compositions (2) and (11) were determined: they were 27 and 25 respectively.

Example 6

An emulsion was prepared according to the method described in Example 1 from 64 cc of diesel, 4 cc of the emulsifier A described in Example 1, 16 cc of methanol and 16 cc of water.

The HLB of the emulsifier used 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

An emulsion was prepared according to the method described in Example 1. It contained 64% by volume of gas oil, 4% by volume of the emulsifier A described in Example 1, 16% by volume of methanol and 16% by volume of water.

The cetane number of this emulsion was 26.

This emulsion was tested in a Diesel engine during a road test on an 80 km course. The emulsion consumption was 48.3 liters, that is a diesel consumption of 30.9 liters. We did the same course but by fueling the Diesel engine with diesel only. Consumption in this case was 39.3 liters.

Example 8

The following emulsions were prepared by mixing in a container 61 cc of diesel and 4 cc of different mixtures of emulsifiers each covering a range of HLB from 5 to 13. On the other hand, a mixture containing 22.5 was prepared cc of water and 12.5 cc of ethanol.

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

The emulsifier mixtures used are the mixtures A to F described in Example 1.

The results obtained are shown in Table 5.

Stability was measured 96 hours after preparing the emulsion. Table 5

* Emulsifier J HLB Index J

! ; 5 5.5 6 6.5 7 8 10 12 15! ! AT ! Ή *. ++ ++ ++ + - - - -!

| B | * H * -H · ++ -H · + - ~ J

1! * JC J -H · ++ Ή "-H- + - - - -! I t!; D; ++++++++++ - - - -, II 1 4 · +; EJ -H- + ++++++ - - - -! - 12 τ For comparison »emulsions were prepared with mixtures of emulsifiers F to L.

“No stable emulsion could be obtained.

Example 9

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 5.5 and 7.

The total volume of each emulsion was 100 cc and each of them contained 22.5 cc of water and 12.5 cc of ethanol. The volume of emulsifier varied between 1 and 10 cc and the volume of diesel varied between 55 and 64 cc.

The emulsion prepared with the emulsifier A described in Example 1 had the following properties indicated in Table 6.

Table 6 | HLB * (Emulsifier mixture (% by volume);; i% 2% 3% 4% 5% β% 8% io%; * * #! 5,5 î - - 44 44 44 44 44 44!!!! I I 6 f ”” ++ 44 44 -H- ++ 44 d 1

6.5 i - 4+ 44 44 +4 44 44 J

♦ f f (? J “" "“ "-“ “f 44; stable after 96 hours -: total demixion 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 to prepare the different emulsions was 6.

The volumes of the various components of the emulsions as well as the stability of the latter are shown in Table 7. The volumes - 13 τ

Table 7 123456789 10 11 12

Diesel 61 '61 61 57 61 61 61 61 61 57 57 57

Emulsifier A444844444 8 8 8 described in Example 1

Ethanol 17.5 20 15 15 14 13 12.5 11 10.5 10 9 8

Water 17.5 15 20 20 21 22 22.5 24 24.5 25 26 27

Stability - ## * ### +++++++ ++ ++ **** • H *: stable after 96 hours *: we have 30% separation after 24 hours * H *: we have 27 % separation after 24 hours t H · # *. there is 25% separation after 48 hours +: there is 12% separation after 48 hours iMHHf ·; we have 7% separation after 96 hours

In addition, the ket indexes of compositions (6) and (11) were determined and they were 28 and 26 respectively,

Example 11

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 Tahleau 8. The volumes are expressed in cc.

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Claims (4)

1. Fuel composition for a diesel engine consisting of an emulsion of the water-in-oil type, characterized in that it comprises from 55 to 92% by volume of diesel oil, from 5 to 35% by volume of an aqueous solution of alcohol chosen from the group comprising methyl alcohol, ethyl alcohol and their mixtures, the percentage by volume of water in this solution being between 43 + 0.20 S and 74, where S is the percentage in 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 sorbitan mono-oleate emulsifiers ethoxylated nonionic emulsifier soluble in l water, the HLB of the resulting emulsifier being between 5 and 6.5. 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 raonolaurate ethoxylated sorbitan having 11 to 40 moles of ethylene oxide, polyethylene glycol monooleate having a molecular weight Λ of between 480 and 1200, ethoxylated nonylphenol having 8 to 50 moles of ethylene oxide, an alcohol ethoxylated fat having 6 to 50 moles of ethylene oxide. 3. Composition according to claim 1 characterized in that its cetane number - 16 r 4. Process for the preparation of a fuel composition for a diesel engine, described in claims 1 to 3, characterized in that the diesel oil and the emulsifier are mixed in a suitable container, and the following are mixed in another container: alcohol and water, and that is introduced while stirring with a conventional agitator the alcohol-water mixture in the diesel-emulsifier mixture. r Λ