EP0171440B1 - Motor fuel - Google Patents

Description

The invention relates to an engine fuel and a method for its production, which consists of a base fuel of hydrocarbons or predominantly hydrocarbons and contains additives of alcohols and optionally additives of ethers and / or ketones and / or aromatics and optionally additives and compounds of lead .

The use of methanol and ethanol as an additive to conventional fuels has long been known. The addition of mixtures of methanol and tert-butanol is also known (Oil and Gas Journal, Dec. 31 (1979) p.48).

However, the problems associated with the practical use of such fuels have only been partially solved, so that it cannot yet be introduced into general driving practice. On the other hand, alternative fuels are becoming increasingly important in numerous countries for economic reasons.

In particular, problems still exist with regard to the phase separation into an alcohol / water and hydrocarbon phase, especially at low temperatures and humid climates, although progress has been made in this case in the addition of methanol to conventional fuel by the simultaneous use of tert-butanol. However, butanols are only available to a limited extent because they are obtained from C ₄ cuts from ethylene plants and are only obtained there if naphtha or medium oil is used as feed, and also at relatively high costs. The availability of an alternative fuel is therefore only available to a limited extent in the event of a relatively large need to add butanols.

It is known to avoid phase separation by adding surface-active compounds. For example, according to EP-A-0 049 921, 0.1-15% of surface-active substances are added, which consist of a mixture of anionogenic and nonionic compounds.

Other problems are still the optimal carburetor setting, ignitability, compression and gas bubble formation at high temperatures. Although the use of pure ethanol for conventional fuels leads to fewer problems compared to methanol, it has not yet been possible to provide fuels with ethanol additions for the usual driving practice that can be used safely by the driver and, in addition, the existing fuel Meet standards (DIN standard 51600 in the Federal Republic). In particular, until today this has not been possible with the use of non-absolute ethanol, which contains approx.4.4% by weight of water as a result of the azeotrope formation during the distillative work-up, and even less possible with water contents which are higher than that of the ethanol / water -Azeotrope at normal pressure.

It is known to the person skilled in the art that when ethanol / water mixtures are distilled at normal pressure in a rectification column at the minimum boiling point of 78.15 ° C. an azeotrope is obtained consisting of 95.57% by weight of ethanol and 4.43% by weight. % Water.

In the fermentation industry, in which so-called bioethanol is obtained from natural products such as fruit, cereals, potatoes, natural products containing sugar, but also cellulose or sulfite waste liquor, the mash obtained from fermentation, which is often very dilute with respect to ethanol, is driven off by an ethanol that does even more Contains water than the azeotrope given above. The stripping devices, which are also referred to as burners, can work discontinuously or continuously. They often have so-called reinforcing columns at the top of the bladder. Depending on the design, the rectifying effect of these attachments results in ethanol qualities with water components of up to 25% by volume.

A fuel containing ethanol with more water than the ethanol / water azeotrope is disclosed in EP-A-0 121 089.

Economically, it is of great interest to be able to add ethanol and especially non-absolute ethanol to conventional fuels and to have an easily accessible alternative fuel based on renewable raw materials that meets all requirements.

Attempts to use pure ethanol without other components, or non-absolute ethanol without other components, as fuel, have not yet led to a usable fuel, especially in European countries, because relatively high costs have to be taken into account and the corresponding distribution system is missing and is also not to be expected in the near future. In addition, the cold start problems, safety-related problems, such as the relatively large explosion area in the gas phase of the fuel tanks or the problem of gas bubbles forming during driving at higher temperatures must be taken into account. Furthermore, ethanol can only be supplied in limited quantities in European countries.

The object of the present invention was therefore to provide a fuel which avoids the specified technical problems, meets all the requirements of the fuel standards, takes into account the availability of the additional components and can be offered to the motorist in the existing gas station distribution network without any problems.

The object was achieved by an engine fuel made from basic fuel consisting of hydrocarbons or predominantly hydrocarbons with alcoholic additives, if appropriate additions of ethers, ketones, aromatics, additives and compounds of lead, characterized in that the same> 0-10% by volume of ethanol and / or non-absolute ethanol and / or technical grade ethanol, where the ethanol or ethanol mixture used can contain water up to and including an amount that corresponds to the ethanol / water azeotrope,> 0 to 10 vol.% butanol and> 0 to 5 vol .-% contains methanol.

Through a variety of laboratory and motor examinations it was found that the The power stop according to the invention is outstandingly suitable for conventional motor vehicle engines, can be mixed as desired with fuels already on the market, changes to the carburettors and engines and other parts which come into contact with the fuel are not required, all requirements of the fuel standards are met and in particular the drop in road octane number (SOZ), which is known to the person skilled in the art when ethanol is added to gasoline and leads to engine damage, is decisively reduced and, moreover, the fuel can be made available to the driver in the existing filling stations.

The fuel according to the invention contains> 0-10% by volume of ethanol, the ethanol being able to contain water in an amount which corresponds to the ethanol / water azeotrope. As ethanol, according to the invention, pure ethanol, non-absolute ethanol, technical ethanol such as. B. synthetic, azeotropic ethanol can be used.

According to the invention, the ethanol used can contain water up to and including an amount which corresponds to the ethanol / water azeotrope, it being possible for the total amount of water to be contained in a certain ethanol used above, or it can be introduced by mixing ethanol types with different water contents.

As a further alcohol component,> 0-10% by volume of butanol is used. Mixtures of n-1- and 2-butanol, isobutanol and tert. -Butanol are used, as well as the individual butanols, the addition of tert-butanol or predominantly tert. -Butanol is preferred.

The third alcohol component according to the invention is methanol, which may contain> 0 to 5% by volume of methanol. The methanol according to the invention can be pure, distilled methanol, so-called pure methanol, as well as technical undistilled methanol, so-called raw methanol or a topped but undistilled methanol from which only a few low boilers have been removed, and mixtures thereof.

To a certain extent, the fuel of the invention may also contain other components, such as. B. aromatics levels that go beyond the aromatics in the base fuel, or certain ethers such. B. methyl tert-butyl ether or methyl tert-amyl ether in amounts up to 20 vol .-%. Furthermore, conventional additives such. B. corrosion inhibitors u. a. or optionally lead in the form of the compounds normally used in fuels.

High-octane gasoline or normal gasoline or mixtures thereof which correspond to the fuel standards are preferably used as base fuels, super-gasoline super-quality, extra-quality or other qualities differently named in different countries being used. The base fuels are preferably fuels which are not less than 10 units in the research octane number (RON) and not less than 9 units in the engine octane number (MOZ), preferably not less than 6 units in the RON and preferably not in the MOZ lower than 5 units and particularly preferably in the RON not lower than 4 units and in the MOZ particularly preferably not lower than 3 units below the octane number of a fuel according to the invention which meets the octane number standard according to any fuel standard. Here, a base fuel can preferably be used which consists of 50 - <100 vol .-% of a high-octane fuel currently on the market and> 0 - 50 vol .-% of a normal fuel currently on the market and> 0 - 25 Vol.- % of the mixture components according to the invention consists of or 50 - <100% by volume of the high-octane fuel and> 0 - 25% by volume of the mixture components according to the invention.

According to the invention, the base fuel can already contain> 0-5% by volume of methanol and / or> 0 to 10% by volume of butanol (s) before the further components are added to it individually or as a mixture. According to the process claimed in accordance with the invention, a mixture which contains 50-100% by volume of ethanol and / or is accordingly added to a base fuel which already contains> 0 to 5% by volume of methanol and / or> 0 to 10% by volume of butanol contains non-absolute ethanol and / or technical grade ethanol, where the ethanol or ethanol mixture used can contain water up to and including an amount that corresponds to the ethanol / water azeotrope and 0 to 50 vol.% butanol and 0 to 50 vol.% Methanol and optionally additives in an amount of 0.01-0.5 g based on 1 L mixture component and optionally a proportion of lead in the form of its compounds from 0 to 0.3 g based on 1 L mixture component.

The investigations have shown that a particularly effective and economical mixing of the components is possible in this way and that fuels already on the market which already contain methanol and / or butanol (s) can also be used to produce the fuel according to the invention.

The fuel according to the invention can also be produced by mixing base fuel, which does not contain methanol and / or butanol (s), with the components according to the invention, the oxygen-containing additives and optionally aromatics being premixed, or by mixing from 50 to <100% by volume of the high-octane fuel and> 0 to 50% by volume of normal fuel with> 0 to 25% by volume of the mixture component or by mixing 50 to <100% by volume of high-octane fuel with> 0 to 25% by volume of the mixture component , where appropriate, additives and lead are additionally admixed in the form of its compounds.

However, these methods according to the invention are not to be regarded as limiting, rather the fuel according to the invention can also be produced by other mixing methods or mixing sequences.

However, numerous additives or additive packages, such as are available on the market, can also be used as additives. Furthermore, lead can be in the form of its Compounds commonly used in fuels are added.

In addition, other alcohols, such as. B. C ₃ - and higher alcohols may be included, as well as ethers such as dimethyl ether, diethyl ether or aromatics such as benzene, toluene and xylenes in amounts that go beyond those already contained in the base fuel.

Mixtures according to the invention are e.g. B. the following (although these examples are not to be considered limiting):

example 1

91% by volume of a high octane fuel was mixed with:

Example 2

90% by volume of a base fuel was mixed with:

Example 3

5 Vol.-% dieses Gemisches wurden zu 95 Vol.-% eines Grundkraftstoffs zugegeben, der bereits 3 Vol.-% Methanol und 2 Vol.-% tert.- Butanol enthielt.A mixture of the following como ducks was made:

5% by volume of this mixture was added to 95% by volume of a base fuel which already contained 3% by volume of methanol and 2% by volume of tert-butanol.

Example 4

94% by volume of a base fuel with an RON of 98.3 and an MOZ of 87.5 was mixed with:

The fuel obtained by mixing had an RON of 99.5 and an MOZ of 88.7.

Example 5

84 vol.% Of a base fuel consisting of 75 vol.% Of a high-octane fuel and 25 vol.% Of a normal fuel were mixed with:

Example 6

A mixture was made from:

Another analogous mixture was prepared in which methyl tert-butyl ether was replaced by acetone.

10% by volume of these mixtures were added to 90% by volume of a high-octane fuel.

Example 7

Der nach Mischen erhaltene Kraftstoff hatte eine ROZ von 96,7 und eine MOZ von 86,9. Ein erfindungsgemäßer Kraftstoff (Beispiel 1) hat folgende Daten:

A base fuel with an RON of 94.8 and an MOZ of 85.3 was mixed with:

The fuel obtained after mixing had an RON of 96.7 and an MOZ of 86.9. A fuel according to the invention (example 1) has the following data:

It has surprisingly been found for the person skilled in the art that the carbon monoxide emission can be significantly reduced with the fuels according to the invention compared to the conventional standard fuels. At the same time it was found that in the lower and middle speed range there is an improved pulling power with a smoother engine running.

The fuels according to the invention lead to a further result that is surprising for the person skilled in the art with regard to the number of road octanes (SOZ) which is very important for the life of engines.

The SOZ of fuels according to the invention are compared with fuels that contain only 2 alcohol components. The SOZ was measured with a 1.6 L Ford Escort engine over a speed range of 2,500 - 4,500 rpm. The figures given represent the decrease in the SCO between 2,500 and 4,500 rpm.

Large decreases in the speed range mentioned mean poor fuel behavior in the engine. Motors have a specific octane number requirement, which must not be undercut even with high load ranges. If this is the case, however, so-called high-speed knocking occurs, which is to be regarded as particularly dangerous because it is not heard by the driver of the motor vehicle.

• ROZ 94,5
• MOZ 85,3
• d₁₅ 0,7414 g/ccm

In the following comparison tests, an unleaded petrol was used as the base fuel with the following data:

• RON 94.5
• MOZ 85.3
• d ₁₅ 0.7414 g / ccm

In the comparative experiments, the following were measured: RON, MOZ and SOZ (road octane number).

The results are summarized in the following table:

A stabilizer was not used in any of the experiments because tert-butyl alcohol has an adequate stabilizer function.

It is known to the person skilled in the art that ethanol additions to gasoline bring about very significant decreases in SOZ in high load ranges. Accordingly, this can be seen from experiments 1a and 4a with decreases of 4 and 3 units respectively, it also being known to the person skilled in the art that tert-butanol itself causes practically no SOZ waste.

However, methanol works differently, which, like ethanol, leads to a significant drop in SOZ.

Comparing the 2-component mixture 1a with the 3-component mixture 1b according to the invention, it is found that only 0.5% by volume of methanol brings with it a surprising disproportionate increase in the RON as well as a reduction in the SOC Decrease that decreases rather than - as would be expected - increases.

Experiments 2a and 2b show that when 2% by volume of ethanol is added, the RON increases compared to 2a and there is only a very slight increase in the decrease in SOZ, it should be noted that in example 4a 2% by volume of ethanol is a Effect SOZ of -3. Analogous results are obtained at 3a / 3b. In comparative experiments 4a / 4b, the SOZ decrease decreases from -3 to -2 units despite the addition of 0.5% by volume of methanol.

The experiments make it clear that synergistic effects occur in the fuel according to the invention, which lead to a significant improvement in the engine behavior in high speed ranges and at the same time, by a slight increase in the proportion of alcohol components, disproportionate increases in the RON occur with already high RON values of the two-component mixtures . Improvements also occur in the MOZ values.

According to the invention, new fuels are now made available to the driver with the properties of conformity to standards, environmental friendliness, availability of the components, usability of the existing distributor system, usability in conventional engines and motor vehicles, technically problem-free production and mixing of the fuel according to the invention, admixture with all those available on the market Standard-compliant fuels and perfect miscibility without the risk of phase separation.

Furthermore, the present invention shows that technical ethanol grades can also be used without impairing the advantages mentioned.

The present invention is undoubtedly of great importance with regard to the dependence on fossil raw materials, in particular on oil.

Claims (13)

1. Motor-fuel based on a hydrocarbon-motor-fuel or based on a motor-fuel consisting predominantly of hydrocarbons, which additionally comprises alcohols and optionally ethers, cetones, aromatics, additives and lead compound(s), characterized in that the motor-fuel comprises > 0 - 10 Vol.-% of ethanol and/or non-dehydrated ethanol and/or technical ethanol, whereby the water content of the ethanol or ethanol-mixture in the motor-fuel may amount up to a quantity, which corresponds to the water content of the ethanol-water azeotropic mixture and comprises > 0 - 10 Vol.-% of butanol and > 0 - 5 Vol.-% of methanol.

2. Motor-fuel according to claim 1, characterized in that the base motor fuel has a research octane number (ROZ), which is not lower than 10 units, and a motor octane number (MOZ) which is not lower than 9 units, preferably a ROZ which is not lower than 6 units and a MOZ, which is not lower than 5 units and particularly preferable a ROZ, which is not lower than 4 units and a MOZ, which is not lower than 3 units below the octane number of an inventive motor fuel, which meets the standard (norm) octane number of any standard (norm) motor-fuel.

3. Motor-fuel according to claims 1 and 2, characterized in that the base motor fuel consists of a motor-fuel with a high octane number like for example Super, Extra and others, and/or of a regular motor-fuel and/or of mixtures of the same.

4. Motor-fuel according to claims 1 to 3, characterized in that it consists of a base motor fuel, which already contains > 0 to 5 Vol.-% of methanol and/or > 0 to 10 Vol.-% of butanol and which is blended with additional oxygen containing components respectively their mixtures and optionally with additional additives and lead compounds respectively their mixtures.

5. Motor-fuel according to claims 1 - 4, characterized in that it consists of 50 - < 100 Vol.-% of the high octane base motor-fuel, > 0 - 50 Vol.-% of the regular base motor-fuel and > 0 - 25 Vol.-% of the additional components.

6. Motor-fuel according to claims 1 - 5, characterized in that ist consists of 75 - < 100 Vol.-% of the high octane base motor-fuel and > 0 - 25 Vol.-% of the additional components.

7. Motor-fuel according to claims 1 - 6, characterized in that it contains non-dehydrated ethanol as ethanol component.

8. Motor-fuel according to claims 1 - 7, characterized in that it contains tert.-butanol as butanol component.

9. Motor-fuel according to claims 1 - 8, characterized in that the methanol component is technical, non-distilled methanol and/or technical, non-distilled, topped methanol or a mixture of the same with pure methanol.

10. Motor-fuel according to claims 1 - 9, characterized in that it contains in addition > 0 - 20 Vol.-% of methyltert.-butylether and/or > 0 - 20 Vol.-% of acetone.

11. Process for the production of motor-fuel according to claims 1 - 10, characterized in that base motor-fuel, which already contains > 0 - 5 Vol.-% of methanol and/or > 0 - 10 Vol.-% of butanol is blended with a blending component, which many contain 50 - 100 Vol.-% of ethanol and/or non-dehydrated ethanol and/or technical ethanol, whereby the water content of the ethanol or ethanol mixture in the motor-fuel may amount up to a quantity, which corresponds to the water content of the ethanol-water azeotropic mixture, and which may contain 0 - 50 Vol.-% of butanol and 0 - 50 Vol.-% of methanol, and optionally additives in a quantity of 0,01 - 0,5 g based on 1 I of blending component and optionally lead as lead compound(s) in a quantity of 0 - 0,3 g based on 1 of blending component.

12. Process for the production of motor-fuel according to claims 1 - 11, characterized in that the oxygen containing components and optionally aromatics are premixed and subsequently added to the base motor-fuel.

13. Process for the production of motor-fuel according to claims 1 - 12, characterized in that 50 - < 100 Vol.- % of the high octane motor-fuel and 0 - 50 Vol.-% of the regular motor-fuel are blended with > 0 - 25 Vol.-% of the blending component or that 75 - < 100 Vol.-% of the high octane motor-fuel are blended with > 0 - 25 Vol.- % of the blending component and that optionally additives and lead as lead compound(s) are added.