FR2846003A1 - Low-lead gasoline fuel, e.g. useful in engines for aircraft or racing vehicles, comprises defined amounts of isoparaffins with 4 or 5 carbon atoms and isoparaffins with 6-9 carbon atoms - Google Patents

Abstract

Fuel with a lead content of 0.56 g/l or less comprises isoparaffins (I) with 4 or 5 carbon atoms, isoparaffins (II) with 6-9 carbon atoms and optionally alkylaromatic hydrocarbons (III) with 6-11 carbon atoms. The fuel contains 45-85 vol.% of (II) and has a (I)/(II) volume ratio of 0.1-0.6. An Independent claim is also included for producing a high-octane fuel with a low lead content by mixing (I), (II) and optionally (III) in amounts such that the fuel contains 45-85 vol.% of (II) and has a (I)/(II) volume ratio of 0.1-0.6.

Description

NEW FUEL WITH HIGH OCTANE INDEX AND LOW LEAD CONTENT

  The present invention relates to novel formulations of

  fuels having a high octane number and lowered levels of organic lead compounds, which can be used to supply internal combustion engines with spark ignition, in particular those fitted to aircraft, or engines 10 with a high compression ratio .

  It is known that prior to their being placed on the market, the fuels intended to supply internal combustion engines with spark ignition must satisfy precise physicochemical characteristics, in order to guarantee to the consumer a high level of mechanical performance and, at the same time , minimize the sources of pollution, whether these are generated by the exhaust gases, or by the product itself during handling or storage. These characteristics, which can vary substantially from one fuel to another, must remain in a field defined by official specifications grouped together and published by qualified organizations, such as AFNOR in France or ASTM in the United States. Among these specifications, that relating to the octane number, that is to say the index measuring the anti-detonation value of a fuel in comparison with a so-called reference gasoline, is an essential characteristic, since it the combustion performance of the fuel in the engine cylinders and, in particular, its knock resistance, that is, its resistance to

  uncontrolled mass autoignition

  Thus, two types of octane numbers are distinguished in the art for gasolines intended to supply engines used in motor vehicles, the RON (Research Octane Number). Research) and the MON (Motor Octane Number, in French, Number of Motor Octane),

  respectively referred to in the profession as Fl and F2.

  In the field of aviation and, more specifically, for aircraft equipped with positive-ignition engines, the fuels offered on the market must be developed with care and, in particular, have a very good resistance to knocking. \ 21700 \ 21726 doc 21 October 2003 - 1/25 obvious reasons of reliability and operational safety at altitude, and especially in view of the severe and particular conditions of use of these engines, which operate at full load during the take-off phase . Two specific octane numbers 5 have therefore been defined and incorporated into the gasoline specifications for aircraft, namely: - the MON or engine octane number (which replaces the former index, formerly known as F3 in the profession ), aiming at appreciating a correct operation of the entire engine in normal operation, that is to say at altitude with stabilized speed; and the supercharge octane number, also called F4 or performance index, reflecting the performance requirements of

combustion of the engine at takeoff.

  Thus, a fuel, commonly referred to as "AVGAS 100 LL", is a piston engine gasoline and spark ignition gasoline, which MON must be, according to ASTM D910-01. (Standard Specification for Aviation Gasolines), or the equivalent standard in Britain DEF STAN (Defense Standard) 91-90 of May 8, 1996, greater than or equal to 99.5; and the F4 greater than or equal to 130. The abbreviation "LL" means "Low Lead", that is to say that the lead content of the fuel, generally coming from alkyl-lead compounds. , must be, according to this standard in force today,

  less than or equal to 0.56 grams per liter of gasoline.

  It is known that gasolines produced directly by distillation of crude oil do not have the required characteristics, in particular of octane, for their direct placement on the aviation market. The refiner must, at the stage of their manufacture, proceed to a mixture of various hydrocarbon bases, in order to obtain products which, with the possible addition of additives, will comply with the different specifications required for their marketing. These bases may consist, for example and without limitation: light distillation fractions containing essentially paraffins containing 4 or 5 carbon atoms; - hydrocarbons derived from the alkylation of gases containing 1 to 4 carbon atoms, free of aromatic or olefinic molecules R \ Patents \ 21700 \ 21726 doc - 21 October 2003 - 2/25 light spirits from direct distillation crude oil, whether it is isomerized or non-isomerized; - and hydrocarbons containing mainly compounds

  aromatic compounds which, by their nature, have high octane numbers.

  However, the fuel octane requirements for aircraft engines are so high that it is generally not possible to economically achieve such fuels, to the required specifications, without resorting to the massive addition of additives. Therefore, the refiner commonly adds an organic lead compound to ensure the specifications of the MON and the

  F4 type 10OLL gasoline, in accordance with ASTM D91001. This compound is generally tetraethyl lead (C8H2OPb), abbreviated "PTE">, whose content in the fuel must comply with the standard and not exceed 0.56 grams of lead per liter of gasoline.

  However, it is known that the use of lead in fuels, because of its harmful nature for health, has been abolished since 1 January 2000 in Europe, and since 1 January 1996 in the United States, for motor spirit, but not for fuels for spark ignition aircraft engines, by special derogation from the Environmental Protection Agency (EPA). Therefore, it is recognized today that gasoline aircraft remains an important source of pollution for the atmosphere. The problem of reducing the lead content in certain gasolines for aircraft engines, and in particular avgaslOOLL, or even its elimination, is therefore particularly acute and will have to be solved in the short or medium term. However, alternative replacements have already been proposed, such as for example the use of: - an unleaded gasoline for aircraft of the type 82UL (specified by ASTM D6227-00) or for an automobile, but these present insufficient anti-rattling characteristics to power the entire existing fleet; a composition of lead-free aviation gasoline, but with additions of oxygenated compounds such as MTBE or ETBE, as described in the patent W002 / 22766; A lead-free gasoline formulated with, among other known hydrocarbon bases, an alkyl terbutyl ether, an aromatic amine and optionally a manganese compound, as claimed in WO97 / 44413; s - an airplane gasoline formulation made from conventional bases with the addition of toluene and an aromatic amine for the

  F4, in accordance with the disclosure of WO94 / 25545;

  - unleaded gasoline manufactured with the addition of MethylcyclopentadienylManganese-Tricarbonyl (abbreviated MMT) 1o in accordance with the teaching of patents EP0540297, EP0609089 and WO94 / 17158, or again; a lead-free composition for gasoline aircraft, manufactured with addition of triptane, as described in the patent

W098 / 22556.

  All the gasoline compositions proposed today pose technical difficulties in formulation to refiners, while generating additional costs by the use of many additives, or specific hydrocarbon bases, made necessary to compensate for the absence or decrease of lead , ie the lack of octane, and therefore to reach the targets

  specified MON and F4. In addition, the environmental compatibilities of the various additives currently used have not yet been fully demonstrated; thus all aromatic amines are classified as toxic, in case of absorption by inhalation or ingestion, and especially for the skin.

  MMT is indexed by the EPA as an air pollutant,

  which may present potential hazards to humans.

  In order to manufacture 10OLL-type gasolines economically and with less risk for the environment, the refiner is therefore confronted with the following alternative: either formulate fuels from the bases currently available in the refinery, but in which the organic lead compounds have been replaced by additions of different additives, or specific hydrocarbon bases, so as to obtain a MON and F4 in accordance with the specification in force. These additions therefore generating a premium for the refiner and possible inconveniences for the environment; R \ Brevcts \ 2 1700 \ 21726 doc 21 October 2003 - 4/25 - to undergo expensive treatments on different bases

  hydrocarbon compounds used in the composition of fuels, to increase their octane number and thus reduce or even eliminate lead, but these different treatments however require complex processes also generating a significant surtax for the refiner.

  The research carried out by the Applicant in the field of the manufacture of fuels has now made it possible to establish, surprisingly, that the precise and rigorous formulation of aviation gasolines, from certain hydrocarbon bases generally available in a refinery of oil, gives them a sufficiently high octane number F4, at least 130, and a MON of at least 99.5 while substantially reducing the organic lead content and, in particular, in PTE, without having recourse to

  octane-providing substitution additives.

  It is therefore an object of the invention to provide novel fuel formulations for internal combustion and spark ignition engines made from a mixture of hydrocarbon bases available in a petroleum refinery and containing a significantly reduced amount of compounds. lead, compared to the prior art formulations, which give these fuels an octane number and

  characteristics in accordance with the standards in force.

  For this purpose, the subject of the invention is a fuel having a lead content less than or equal to 0.56 gram per liter of fuel, containing at least a first hydrocarbon base (B 1) consisting essentially of isoparaffins comprising 4 or 5 carbon atoms, as well as at least one second hydrocarbon base (B2) consisting essentially of isoparaffins comprising 6 to 9 carbon atoms, and optionally at least one complement (B3) consisting essentially of alkylaromatic hydrocarbons; comprising 6 to 11 carbon atoms, in which: - the content of the base B2 in the fuel is between% and 85% by volume and preferably between 50% and 82% by volume, and in that R: \ Patents \ 21700 \ 21726 doc - 21 October 2003 - 5/25 - the ratio of quantities in% volume Bi / B2 is included

  between 0.10 and 0.60 and preferably between 0.15 and 0.45.

  For this purpose, the subject of the invention is also a fuel having a lead content of less than or equal to 0.56 gram per liter of fuel, containing at least a first portion of isoparaffins comprising 4 or 5 carbon atoms, and at least one second part of isoparaffins comprising 6 to 9 carbon atoms, and optionally at least one complementary part of hydrocarbons of alkylaromatic type comprising 6 to 11 carbon atoms, in which: the content of the isoparaffins comprising from 6 to 9 carbon atoms in the fuel is from 45% to 85% by volume and preferably from 50% to 82% by volume, and in that the ratio of the isoparaffin% volume amounts comprising 4 or 5 carbon atoms / isoparaffins comprising 6 to 9 carbon atoms is between 0.10 and 0.60 and preferably

between 0.15 and 0.45.

  In the present specification: "essentially consisting of" means the presence of a large amount, preferably greater than 70% by volume, of the compounds mentioned in the corresponding hydrocarbon base; the lead contents are cited by reference to the methods for measuring the lead contents, described in ASTM D334 1 (iodine monochloride method) or ASTM D5059 (X-ray spectrometry method); - MON and F4, are measured respectively in agreement with

ASTM D2700 and ASTM D909.

  According to the invention, the ratio of the amounts in% by volume B3 / B2 is between 0.00 and 0.60, and preferably between 0.00 and 0.55; alternatively, the ratio of the amounts in volume hydrocarbons of alkylaromatic type comprising 6 to 11 carbon atoms / isoparaffins comprising 6 to 9 carbon atoms is

  between 0.00 and 0.60 and preferably between 0.00 and 0.55.

  The use of at least two cuts (B 1), (B2) as well as, preferably, with at least the cut (B 3), and their incorporation into the abovementioned relative amounts, allows the refiner to formulate fuels simultaneously having a high octane number and R: \ Patents \ 21700 \ 21726 doc - 21 October 2003 - 6/25

  a lowered lead content of less than or equal to 0.56 grams per liter, preferably less than or equal to 0.42 grams per liter, even more preferably less than or equal to 0.35 grams per liter, totally preferred less than or equal to 0.28 gram per liter and ideally equal to 0.14 gram per liter of fuel.

  Indeed, the fuels according to the invention can be manufactured from hydrocarbon bases available in a conventional refinery, and reach high octane numbers, which comply with the most stringent standards such as the ASTM D910-01 standard, while

  with a lead content of up to 0.27 g / l or less. Thus, with severely processed bases, it is possible to formulate aircraft fuels with a lead content of only 0.14 g / l. The refiner therefore adds less lead derivative than it did before.

  In the present description, reference is made mainly to

  fuels for aircraft engines, but the fuels according to the invention can be used in fields other than aviation, and in particular to supply, alone or in mixture, the 20 spark ignition engines of all types of vehicles, including aircraft. The use of the fuel according to the invention is particularly advantageous for supplying the engines of competition vehicles or the like, that is to say for engines with a high compression ratio, requiring fuels with a very high octane number. The fuel object of the present invention can also be used to feed, alone or in mixture, very different types of systems, for example, a fuel treatment unit, such as a reformer, coupled to a fuel cell. The first hydrocarbon base (B 1) used for the manufacture of the fuels according to the invention belongs to the family of paraffinic hydrocarbons and can be, for example, a light base containing at least 80% by volume, and preferably at least 80% by volume. less than 90% by volume of isoparaffinic molecules comprising between 4 or 5 carbon atoms and preferably 5 carbon atoms. Even more preferably, the 5-carbon molecules consist of at least 90% by volume of isopentane. R \ Brevers \ 2 1700 \ 21726 - 21 October 2003 - 7/25 This light paraffinic base may be derived, for example, from a fractionation of the lightest fraction of the distillate produced by the atmospheric distillation of crude oil or from a unit

isomerization of alkanes.

  Advantageously, this hydrocarbon fraction can contain up to 10% by volume of isoparaffins with 4 carbon atoms; the latter being constituted by at least 5% by volume of isobutane, when it is necessary to increase the vaporization of the fuel for

  the ignition of the spark ignition engine.

  The second base used (B2) typically contains at least

  % by volume, and preferably at least 90% by volume, isoparaffins containing between 6 and 9 carbon atoms, and preferably 8 carbon atoms. These isoparaffinic hydrocarbons having 8 carbon atoms are at least 70% by volume, and preferably at least 75% by volume of isooctanes.

  Such a hydrocarbon base can come from different crude oil processing processes, generally present in an oil refinery. In particular, this isooctane-rich hydrocarbon cut, also called "alkylate" in the art, can be produced, for example, by the alkylation process of isobutane.

by light olefins.

  An alternative is to replace part of this isoparaffinic cut, and at the same time reduce the proportion of alkylate, which is a petroleum base with a relatively high manufacturing cost, by cutting hydrocarbons from a isomerization unit of light species, the latter being

  from the distillation of crude oil.

  The complement used (B3) is a hydrocarbon fraction containing from 6 to 11 atoms, the content of aromatic compounds containing 6 to 9 carbon atoms being typically higher or

  equal to 80% by volume, and preferably greater than or equal to 85% by volume. Even more preferably, these aromatic compounds contain 7 carbon atoms and are toluene, whose content in the balance (B3) is greater than or equal to 45% by volume, and preferably greater than or equal to 50% by volume. .

  This hydrocarbon base used in the formulation of gasolines for aircraft engines, generally comes from a process of manufacture, known as "reforming" of gasolines, available in patent pending. In particular, in an oil refinery. This process makes it possible, by means of a set of chemical reactions carried out at high temperature and under high pressure, necessarily in the presence of an appropriate catalyst, to transform straight or cyclic chain molecules contained in the heavier species by example produced by direct distillation of crude oil, branched hydrocarbons and more stable aromatic cyclic. These aromatic hydrocarbons are generally called "reformates" in the

  profession and have a high octane number.

  In addition to the bases (B1), (B2) and (B3), the fuel according to the invention can contain many other bases. These can be chosen in particular from all the bases likely to enter the composition of the essences. These bases may be derived from conventional refining operations (for example, but not limited to, distillation of crude oil, catalytic cracking, hydrocracking, reforming processes, isomerization, alkylation, and the like. ...), but also include synthetic hydrocarbons such as those obtained by oligomerization

  of olefins or by Fischer-Tropsch synthesis.

  Preferably, these additional bases are chosen from those having a distillation range of between 250 ° C. and 1750 ° C. (determined according to ASTM D 86) and even more preferably between 750 ° C. and 135 ° C. Those skilled in the art will readily be able to determine the nature and the quantities of additional bases that may be incorporated in the fuel according to the invention, given the application for which this is intended.

  fuel and bases available in the refinery.

  Each base used in the composition of the fuel according to the invention, that is to say (BI), (B2), (B3), as well as any additional base, may advantageously have undergone all or part of a desulfurization treatment and and / or denunciation and, possibly, dearomatization, at any stage of its elaboration. For example, bases which have been hydrotreated under more or less severe conditions (including hydrodesulphurization and / or saturation of aromatic compounds may be used.

  and olefinic and / or hydrodenitrogenation).

  The fuel according to the invention advantageously has a sulfur content (determined according to the standards ASTM D 1266 or ASTM R \ Patents 21700 \ 21726 doc - 21 October 2003 - 9/25 D2622) less than or equal to 500 ppm by weight, preferably less than or equal to 100 ppm by weight, even more preferably, a

  in sulfur less than or equal to 50 ppm by weight, or even 10 ppm by weight.

  The fuel according to the invention may contain one or more additives, which the person skilled in the art will readily be able to choose from among the many additives conventionally employed for fuels. The choice of these additives depends essentially on the application for which the fuel is intended. These include, but are not limited to, corrosion inhibitor, anti-freeze or antistatic additives, cold properties additives, additives

  tracers or detergent additives, and mixtures thereof.

  For example, when the fuel is intended for use

  in aviation, it can inter alia contain at least one antioxidant agent chosen from sterically hindered phenols (such as, for example, 2,6-di-t-butyl-4-methylphenol (BHT), 2,6-di t-butylphenol, and 2,4-di-methyl-6-t-butylphenol).

  The determination of the contents of the fuel in any other usual hydrocarbons and additives, with a view to bringing it into conformity with the regulations in force in the art or with particular characteristics, falls within the competence of the skilled person.

  profession and does not pose any particular technical problem.

  The invention also relates to a process for preparing the low lead and high octane fuel in which the mixture is mixed, by means known in the art, with at least one first hydrocarbon base (B 1). consisting essentially of isoparaffins comprising 4 or 5 carbon atoms, and at least one second hydrocarbon base (B2) consisting essentially of isoparaffins comprising 6 to 9 carbon atoms, and preferably at least one complement (B3 ) consisting essentially of hydrocarbons of alkylaromatic type comprising 6 to 11 carbon atoms and, if appropriate, additives customary for this type of fuel, in such quantities that: the content of the base B2 in the fuel is between % and 85% by volume, and preferably between 50% and 82% by volume, and in that - the ratio of the quantities in% by volume B1 / B2 is included

  between 0.10 and 0.60 and preferably between 0.15 and 0.45.

  The invention finally relates to the use of such a fuel for the purposes of the present invention.

  to reduce the polluting emissions of a spark-ignition engine.

  Indeed, in addition to the reduction of pollution due to the lowering of the lead content in the fuel, the latter also leads to a decrease in the methyl bromide content, produced during the combustion of the IOOLL avgas. This methyl bromide, having recognized destructive effects on the ozone layer of the atmosphere, comes from the dibromoethane which is added (in English and in the profession: "scavenger") during the manufacture of the 10OLL gasoline of 10 way to trap the lead in the engine cylinders, and allow

  its elimination by volatility after the combustion cycle.

  According to one embodiment, the lead content is lower than

  at 0.56 grams per liter of fuel.

  According to one embodiment, the content of the B2 base is between 55 and 75% by volume.

  According to one embodiment, the content of the base B 1 is

between 12 and 30% by volume.

  According to one embodiment, the fuel comprises less than% by volume of cycloparaffins comprising 5 to 8 carbon atoms. According to one embodiment, the ratio of the amounts in% by volume B3 / B2 is between 0.1 and 0.60 and preferably between

0.2 and 0.45.

  In one embodiment, the lead content is less than or equal to 0.26, preferably less than 0.14 grams per liter of fuel. According to another embodiment, the lead content is between 0.10 and 0.28, preferably between 0.14 and 0.26 gram.

per liter of fuel.

  According to one embodiment, the lower heating value (determined according to ASTM D4529) is between 39.1 MJ / Kg and 43.5 MJ / Kg, preferably between 39.1 MJ / Kg and 43 MJ / Kg, advantageously between 39.1 MJ / Kg and 42.2 MJ / Kg, more

  advantageously between 39.1 MJ / Kg and 41.3 MJ / Kg.

  The lowering of the lead content in the fuel according to the invention is particularly advantageous for the following reasons, alone or in combination: R: \ Patents \ 21700 \ 21726 doc - 21 October 2003 - 11/25 - it complies with the existing specifications and does not have the disadvantages for the environment of conventional fuels for the same applications, for a significantly lower manufacturing cost thereof; - it does not incorporate octane-providing additives other than a reduced quantity of organic lead compounds; - its environmental qualities are more adapted to the current requirements; its lower lead content makes it possible to lower the scavenger content; and - it is compatible with all other fuels for

spark ignition engines.

  Other features and advantages of the invention

  will appear in the detailed examples which follow, which are not limiting in nature.

EXAMPLES

Example 1

  From the hydrocarbon bases B1, B2 and B3 which are generally found in a petroleum refinery and whose compositions are shown in Table 1 below, the Applicant has formulated 4 fuels (labeled Cl to C4) in accordance with to the invention, and 4 other mixtures outside the scope of the invention (identified

C5 to C8).

  TABLE 1 / Composition of the 3 bases B 1, B2 and B3 B1 Isoparaffins in C5: 95.47% by weight Paraffins in C5 and C4: 3.34% by mass C4 and C5 olefins: 1.19% mass B2 C8 isoparaffins: 82.87% mass C6, C7 and C9 isoparaffins: 10.02% mass C5, C10 and C11 isoparaffins: 5.75% mass C4 paraffins and Cl: 1.29% by weight C9 olefins: 0.02% by weight C 11 aromatics: 0.05% by mass B3 C7 aromatics: 51.72% by C8 aromatics: 26.36% by C9 aromatics 9,84% Aromatic mass in C6, C10 and C11: 1,74% mass Paraffins in C4 to C11: 2,54% mass Isoparaffins in C4 to C9: 5,99% mass Others: 1,81% mass For each fuel thus manufactured, the main physicochemical characteristics (see Table 2) were measured in accordance with ASTM D910-01. Table 2 / Main Features of 10OLL Aircraft Gasoline and Related Analysis Methods _ Specifications ASTM D-910-01 min. 130.0 F4

ASTM D909 MON

  ASTM D2700 PCI MJ / Kg ASTM D4529 TV (38 C, KPa) ASTM D5191 10% evaporated C

ASTM D86

% evaporated C

ASTM D86

  % evaporated. C ASTM D86 Final Point ASTM D86 Pb g / l

ASTM D2392

  min. 99.5 min. 43.5 min. 38.0 max 49.0 max. 75 max. 105 max. 135 max. 170 max. 0.56 PCI: Lower Heat, in English "Net Heat of Combustion N 10 TV: Steam Voltage, in English" Vapor Pressure "R \ Patents \ 21700 \ 21726 doc - October 21, 2003 - 13/25 The results of the measurements are shown in Table 3 Table 3 / Fuel Manufacture and Characteristics thereof according to ASTM D910-01 Mixtures C1 C2 C3 C4 C5 C6 C7 C8 B1 (% v) 21.2 21.1 12.0 17, 3 37.5 7.0 61.5 19.8 B2 (% v) 50.8 57.9 68.7 57.5 40.0 91.2 20.8 31.2 B3 (% v) 28.0 21.0 19.3 25, 2 22.5 1.8 17.7 49.0

  B1 / B2 0.42 0.36 0.17 0.30 0.94 0.07 2.96 0.63

  B3 / B2 [0.55 0.36 0.28 0.44 [0.56 0.02 0.85 1.57

F4

  ASTM 150.0 130.0 131.8 130.0 130.9 130.8 105.7 132.3

D909 MON

  ASTM 105.6 102.0 102.0 101.4 102.8 103.2 100.8 99.8

  ASTM 43.5 43.8 43.8 43.6 43.7 44.5 44.0 42.6

  D4529 TV (38 C, KPa) 48.0 49.0 38.0 43.6 69.3 34.5 100.0 42.9

ASTM D5191 10%

  evaporated. C 62.2 61.6 72.0 66.4 42.8 76.1 14.6 65.9 ASTM D86% evaporated. C 103.7 101.9 105.0 104.5 95.9 102.3 85.23 109.8 ASTM D86% evaporated. C 122.7 118.9 118.2 121.3 119.2 108.8 115.9 134.2 ASTM D86 Final Point

   C 157.2 152.8 151.9 155.6 153.4 140.9 149.9 170.6

ASTM D86

Pb g / l

  ASTM 0.54 0.30 0.28 0.27 0.38 0.30 0.27 0.23

  D2392 Specifications ASTM D-910-01 I Min. 130.0 Min. 99, 5 Min. 43.5 Min. 38.0 Max 49.0 Max. 75 Max. 105 Max. 135 Max. 170 Max. 0.56 Table 3 shows that the fuels formulated according to the present invention (C 1 to C 4) satisfy for the 100LL avgas. A main features of the ASTM D910-01 contrario, when the B2 content in fuels (C5 to C8) is not between 45% and 85% by volume, or the ratio B 1 / B2 is not not within the 0.10-0.60 range, the specifications are not met. This table also teaches that it is possible R- \ Brevets \ 21700 \ 21726 doc - 21 octobre 2003 - 14/25

  to formulate a fuel, with a lead content equal to 0.27gram per liter of fuel while respecting the standard in force (C4).

Example 2

  This example is identical to Example 1, but the C9 to C16 fuels were formulated from purified bases B1, B2 and B3, whose new respective compositions are indicated in the following Table 4. Table 4 / Composition of the 3 bases B1 Isoparaffins in C5: 100.00% mass B2 Isoparaffins in C8: 99.97% mass Isoparaffins in C7: 0.03% mass B3 Aromatics in C7: 99.95% Aromatic mass in C5 and C8: 0.05% mass The results of the measurements are given in Table 5 R. \ Patents \ 21700 \ 21726 doc - 21 October 2003 - 15/25 Table 5 / Manufacture of fuels according to ASTM D9 10-01 and characteristics of these Mixtures C9 C10 C11 C12 C13 C14 C15 C16 B1 (% v) 26.1 16.2 17.2 19.3 29.5 38.5 7.5 20.8 B2 (% v) 47.9 83.6 68.1 54.8 28.8 43.2 89.2 30.7 B3 (% v) 26.0 0.2 14.7 25.9 41.7 25.3 3.3 48.5

  B1 / B2 0.54 0.19 0.25 0.35 1.02 0.89 0.08 0.68

  B3 / B2 0.54 0.01 0.21 0.47 [1.44 0.58 0.03 1.58

F4

  ASTM D909 155.0 134.9 130.1 130.0 130.4 132.2 130.5 142.0

MY

  ASTM 107.9 105.4 102.7 101.2 99.6 104.4 103.3 99.7

D2700

  ASTM 43.5 44.7 44.0 43.5 42.8 46.7 44.6 42.4

  D4529 TV (38 C, KPa) 48.9 38.0 38.0 39.6 52.1 67.0 25.6 39.6 ASTM D5191% evaporated.'C 61.6 73.6 73.1 70, 8 57.8 51.4 85.7 70.1 ASTM D86% evaporated.TC 98.6 95.4 98.5 100.4 101.2 101.9 98.6 105.2 ASTM D86% evaporated.c 102 , 1 95.6 99.1 101.8 106.0 109.1 96.0 107.3 ASTM D86 Final Point oC 111.9 103, 3 108.2 111.9 117.1 118.7 104.5 119 5

ASTM D86 0

Pb g / i

  ASTM 0.54 0.28 0.18 0.14 0.14 0.23 0.17 0.14

  D2392 Specifications ASTM D-910-01 Min. 130.0 Min. 99, 5 Min. 43.5 Min. 38.0 Max 49.0 Max. 75 Max. 105 Max. 135 Max. 170 Max. 0.56 As in accordance with

Example

  1, the fuels formulated in the present invention (C9 to C12) satisfy the

  main features of the ASTM D910-01 for the 100LL avgas.

  In addition, with the use of purified bases, the content of 0.14 grams of lead per liter of fuel can be achieved (C12), while ensuring the specifications of 100 LL gasoline. On the other hand, when the content of the B2 base in the fuels (C13 to C16) is not between 45% and 85% by volume, and the ratio B 1 / B2 is not within the 0.10-0.60 range, the specifications do not

are not reached.

  R \ Patents \ 21700 \ 21726.doc - 21 October 2003 - 16/25

Example 3

  Given that the "CRC-unleaded Aviation Gasoline Development Group" has considered in its preliminary report of November 18, 1999, a possible relaxation of the specification of the 5 lower calorific value of gasoline 1 OOLL, up to several percents of the nominal value, the Applicant has established the fields of formulations for fuels meeting the specifications of ASTM D910-01, for different levels in plumb, and several values of minimum PCi, ranging from 43.5 to 10 39, 1 MJ / Kg, when these fuels are made with bases

  industrial oil refinery type, or purified products.

  The results are shown in Tables 6 and 7

1 / Industrial bases.

  The bases B 1, B2 and B 3 have the physico-chemical characteristics according to Table 1 above.

  Table 6 / Fields of 100LL gasoline formulations from industrial bases, for different lead levels and several

minimum PCi values.

  PCi (ASTM D4529 ≥43.5 ≥43.0 ≥ 42.6 ≥ 42.2 ≥ 41.3 ≥ 39.1% deconstructed 0 -1% -2% -3% -5% -10% Pb content ( 9g / I of fuel)

0,00 DO DO DO DO DO DO

0.08 OD DO DO OD OD OD

0.09 DO DO DO DO DO DO

0.10 DO DO DO DO DO DO

0.10 1 DO DO DO DO DO DO

0.11 DO DO DO DO DO DO

0.123. DO DO DO DO DO DO

0.14 DO DO DO DO DO DO

0.15 DO DO DO DO DO DO

0.16 DO DO DO DO DO

0.17 DO DO DO DO DO DO

0.18 DO DO DO DO DO DO

0.24 DO DO DO DO DO DO

0.25 i DO DO DO D D D

0.26 DO DO DO DO DO DO

0.27 i D1 D4 D7 D9 D12 D13

0.28? D2 D5 D8 D10 D14

  D means that there is no possible field of formulation of a 100LL gasoline which respects the main characteristics of the product. the

ASTM D910-01.

  It can be seen from Table 6 that with petroleum hydrocarbon bases or cups, generally available in a petroleum refinery, as defined in Table 1, the lowest lead content permissible for making a fuel of the current standard is 0.27g / 1 (D1), regardless of the value of the minimum PCi between 43.5 and 39.1 MJ / Kg (D4, D7, 10 D9, D12 and D13).

  2 / Purified bases The physico-chemical characteristics of the bases B1, B2 and B3 are indicated in Table 4 above. Table 7 / Fields of Formulations of 100LL Gasoline from Purified Bases, for Different Levels of Lead and More

minimum PCi values.

  | - a, D> * - i 8si PCi (ASTM D4529 ≥ 43.5 ≥ 43.0 ≥ 42.6 ≥ 42.2 ≥ 41.3 ≥ 39.1% deconstructed l 0 -1% -2% -3 % -% -10% A 30 Pb content (cj / l of fuel)

0,00 DO

0.08 OD

0.09 DO

0.10 OD

0.11 DO

0.12 DO

0.13 OD

0.14 Dl 0.15

0.16 D3

0.17 D4

0.18 D5

0.28 D6

0.56 -> 'R-' uvRUs -0v

DO DO DO DO DO

DO DO DO DO DO

DO D19 D26 D38 D39

D8 D20 D27 D40

D9 D21 D28 D41

D10 D22 D29 D42

D23 D23 D30 D43

D12 D24 D31 D44

D13 D25 D32 D45

D14 D33 D46

D15 D34 D47

D16 D35 D48

D17 D36 D49

D18 D37 D50

  DO means that there is no possibility of formulating a essence

  LL respecting the main characteristics of ASTM 35 D91001.

  It can be seen from Table 7 that with purified products, as defined in Table 4 above, it is possible to formulate a gasoline airplane containing 0.14 g / l of lead (D1), while respecting R Patents \ 21700 \ 21726 doc - 21 October 2003 - 18/25 the characteristics defined in the current standard of petrol 100LL aircraft. In addition, this minimum lead content reaches 0.10 g / l (D8) when the minimum PCi value is decreased to 43.0 MJ / kg (1% deconstructed), it is 0.09 g / l ( D19) for a minimum PCI value of 42.6 MJ / Kg (2% less stress) and less, up to 39.1 MJ / Kg (10% deconstraint). Characterizing the minimum PCi at 1% below the value of the current standard reduces the lead content by approximately 28%, this decrease is 36%.

  % when the minimum PCi is deconstructed by 2% or more.

  The fuels thus produced, in accordance with the invention, have various advantages, alone or in combination: they have a high octane number, thus meeting the specification in octane numbers F4 and MON of the 100LL gasoline plane, without the need for additional additions of octane feed additives; - they are environmentally friendly because they contain fewer organic compounds of lead and scavenger; - they are cheaper to manufacture; they make it possible to reduce the impact of lead pollution on the health of living beings; - Finally, they are compatible with other equivalent hydrocarbons. R '\ Patents \ 2 1700 \ 21726 doc - 21 October 2003 - 19/25

Claims (28)

  1.- A fuel having a lead content of 0.56 g / l or less of fuel, containing at least a first hydrocarbon base (B 1) consisting essentially of isoparaffins comprising 4 or 5 carbon atoms, and at least one second hydrocarbon base (B2) consisting essentially of isoparaffins comprising 6 to 9 carbon atoms, and optionally at least one complement (B3) consisting essentially of alkylaromatic hydrocarbons comprising 6 to 11 carbon atoms; in which: the content of the base B2 in the fuel is between% and 85% by volume and preferably between 50% and 82% by volume, and in that the ratio of the quantities in% by volume B1 / B2 is understood   between 0.10 and 0.60 and preferably between 0.15 and 0.45.   2. Fuel according to claim 1, characterized in that the lead content is less than 0.56 grams per liter of fuel. 3.Fuel according to claim 1 or 2, characterized in that   that the content of the base B2 is between 55 and 75% by volume.   4. Fuel according to claim 1, 2 or 3, characterized in that the content of the base B 1 is between 12 and 30% by volume.   5. Fuel according to one of claims 1 to 4, characterized   in that it comprises less than 5% by volume of cycloparaffins comprising 5 to 8 carbon atoms. 30   6. Fuel according to one of claims 1 to 5, characterized   in that the first base (B1) comprises at least 80% by volume, and preferably at least 90% by volume, of isoparaffins with 5 atoms of carbon.   7. Fuel according to one of claims 1 to 6, characterized   in that the isoparaffins with 5 carbon atoms are constituted   at least 90% by volume of isopentane.   R: \ Patents \ 21700 \ 21726.doc - 21 October 2003 - 20/25   8. Fuel according to claims 1 to 7, characterized in that   that the content of isoparaffins with 4 carbon atoms in the base   (B1) is less than or equal to 10% by volume.   9. Fuel according to any one of the claims   preceding, characterized in that the second base (B2) comprises at least 80% by volume, and preferably at least 90% by volume, isoparaffins with 8 carbon atoms. 10. Fuel according to claim 9, characterized in that the isoparaffins containing 8 carbon atoms consist of at least 70% by volume, and preferably at least 75% by volume of isooctanes.   11. Fuel according to any one of the claims   preceding, characterized in that the complement (B3) comprises at least 80% by volume, and preferably at least 85% by volume of aromatic compounds containing 6 to 9 carbon atoms. 12. Fuel according to claim 11, characterized in that the aromatic hydrocarbons consist of at least 45% by weight.   volume, and preferably at least 50% by volume of toluene.   13. Fuel according to one of the preceding claims,   characterized in that the ratio of the amounts in% volume B3 / B2 is   between 0.00 and 0.60 and preferably between 0.00 and 0.55.   14. Fuel according to one of the preceding claims, characterized in that the ratio of the amounts in% volume B3 / B2 is   between 0.1 and 0.60 and preferably between 0.2 and 0.45.   15.- A fuel having a lead content less than or equal to 0.56 grams per liter of fuel, containing at least a first part of isoparaffins comprising 4 or 5 carbon atoms, and at least a second part of isoparaffins comprising 6 to 9 carbon atoms, and optionally at least one complementary part of hydrocarbons of alkylaromatic type comprising 6 to 11 carbon atoms, in which: ## STR1 ## the content of the isoparaffins comprising 6 to 9 carbon atoms in the fuel is between 45% and 85% by volume and preferably between 50% and 82% by volume, and in that - the ratio of isoparaffins in volume% quantities comprising 4 or 5 carbon atoms / isoparaffins comprising 6 to 9 carbon atoms is between 0.10 and 0.60 and preferably between 0.15 and 0.45.   16. Fuel according to claim 15, characterized in that the lead content is less than 0.56 gram per liter of fuel. 17.Fuel according to claim 15 or 16, characterized in that the content of the isoparaffins comprising 6 to 9 carbon atoms.   carbon in the fuel is between 55 and 75% by volume.   18. Fuel according to claim 15, 16 or 17, characterized in that the content of the isoparaffins comprising 4 or 5 carbon atoms.   carbon in the fuel is between 12 and 30% by volume.   19. Fuel according to one of claims 15 to 18,   characterized in that it comprises less than 5% by volume of cycloparaffins comprising 5 to 8 carbon atoms.   20. Fuel according to one of claims 15 to 19,   characterized in that the ratio of the amounts in volume hydrocarbons of alkylaromatic type comprising 6 to 11 carbon atoms / isoparaffins comprising 6 to 9 carbon atoms is   between 0.00 and 0.60 and preferably between 0.00 and 0.55.   21. Fuel according to one of claims 15 to 20,   characterized in that the ratio of hydrocarbons of the alkylaromatic type comprising 6 to 11 carbon atoms / isoparaffins comprising 6 to 9 carbon atoms is   between 0.1 and 0.60 and preferably between 0.2 and 0.45.   R '\ Patents \ 21700 \ 21726 doc - 21 October 2003 - 22/25   22.- Fuel according to one of the preceding claims,   characterized in that its lead content is less than or equal to 0.42 grams per liter of fuel, preferably 0.28 grams per liter of fuel.   23.- Fuel according to one of claims 1 to 22,   characterized in that its lead content is less than or equal to   0.26, preferably less than 0.14 grams per liter of fuel.   24.- Fuel according to one of claims 1 to 22,   characterized in that its lead content is between 0.10 and 0.28, preferably between 0.14 and 0.26 grams per liter of fuel.   25.- Fuel according to one of the preceding claims, characterized in that its octane number F4 is equal to or greater than 130.   26.- Fuel according to any one of claims 1 to   characterized in that its lower heating value (determined according to ASTM D4529) is greater than or equal to 39.1 MJ / Kg, and   preferably greater than or equal to 43.5 MJ / Kg.   27.- Fuel according to any one of claims 1 to   characterized in that its lower heating value (determined according to ASTM D4529) is between 39.1 MJ / Kg and 43.5 MJ / Kg, preferably between 39.1 MJ / Kg and 43 MJ / Kg, advantageously between 39.1 MJ / Kg and 42.2 MJ / Kg, more   advantageously between 39.1 MJ / Kg and 41.3 MJ / Kg.   28. A method for preparing a low-lead and high-octane fuel in which is mixed at least a first hydrocarbon base (B 1) consisting essentially of isoparaffins comprising 4 or 5 carbon atoms. carbon, and at least one second hydrocarbon base (B2) consisting essentially of isoparaffins comprising 6 to 9 carbon atoms, and optionally a complement (B3) consisting essentially of hydrocarbons of alkylaromatic type comprising 6 to 11 carbon atoms in amounts such that: the content of the B2 base in the fuel is between% and 85% by volume and preferably between 50% and 82% by volume, and in that - the ratio of the quantities in volume% B 1 / B2 is between 0.10 and 0.60 and preferably between 0.15 and 0.45. 29. The process according to claim 28 for the preparation of a   fuel according to one of claims 1 to 27.   30.- Use of the fuel according to one of claims 1 to   27 for feeding, alone or in mixture, an ignition engine controlled aircraft.   31.- Use of the fuel according to one of claims 1 to 15 27 for feeding, alone or in mixture, an ignition engine   controlled competition vehicle or similar.   32.- Use of the fuel according to one of claims 1 to   27 for feeding, alone or in mixture, a fuel treatment unit, such as a reformer, coupled to a fuel cell.   33.- Use of the fuel according to one of claims 1 to   27 to reduce the polluting emissions of a spark ignition engine. R: \ Patents \ 21700 \ 21726.doc - 21 October 2003 - 24/25