US 2011 011 4536A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2011/0114536A1 Demoment (43) Pub. Date: May 19, 2011
(54) AVIATION GASOLINE FOR AIRCRAFT (30) Foreign Application Priority Data PISTON ENGINES, PREPARATION PROCESS THEREOF Jun. 30, 2008 (FR) ...... O8 O3654 (75) Inventor: Pascale Demoment, Le Havre (FR) Publication Classification (51) Int. Cl. (73) Assignee: Total Raffinage Marketing, CIOL L/04 (2006.01) Puteaux (FR) (52) U.S. Cl...... 208/16 (21) Appl. No.: 13/001,932 (57) ABSTRACT The Subject of the present disclosure is an aviation gasoline (22) PCT Filed: Jun. 29, 2009 composition that is lead-free and free of oxygenated com pounds meeting the specifications of the ASTM standard (86). PCT No.: PCT/B2O09/OO6114 comprising isopentane, isooctane, and (alkyl)aromatics. The aviation gasoline composition according to the disclosure S371 (c)(1), may be obtained simply and economically from a mixture of (2), (4) Date: Dec. 29, 2010 hydrocarbon bases usually available in a refinery.
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AVIATION GASOLINE FOR AIRCRAFT reliability and safety of operation during the taking-off phase PISTON ENGINES, PREPARATION PROCESS and in altitude, it is not obvious to use these additives for THEREOF aviation gasoline, for which the constraints are much stricter than those required for automotive gasolines. FIELD OF THE INVENTION 0011. As regards aviation gasoline, in order to replace the lead additives, solutions have been proposed in the literature, 0001. The present invention relates to a lead-free aviation Such as by adding other additives or components, such as gasoline composition (AVGAS) and free of an oxygenated aromatic amines, for example aniline, alkylaniline, methyl compound, intended for aircraft with piston or reciprocating cyclopentadienyl manganese tricarbonyl (MMT). engines. In particular, the object of the present invention is (0012 EP 540297 and EP 609089 propose adding meth lead-free aviation gasoline with an octane number MON ylcyclopentadienyl manganese tricarbonyl (MMT) to avia (Motor Octane Number) F2 greater than or equal to 91 and tion gasoline as a Substitute for lead. having very good combustion characteristics. (0013. In EP 609 089 lead-free aviation gasolines are described, based on alkylates, in which an ether is added. Such TECHNOLOGICAL BACKGROUND as ETBE or MTBE, as well 0.4 to 0.5 g/gallon of manganese 0002 Aviation gasoline is a product which is elaborated in the form of the cyclopentadienyl manganese tricarbonyl with care and Subject to severe regulations, which go hand compound. The problem of the invention was not discussed in-hand with any aeronautical application. Thus, the prepara since the described gasoline is notabase of the AVGAS type: tion in a refinery of aviation gasoline is carried out with bases it comprises alkylates, but does not comprise reformates, or characterized by both a narrow distillation interval and high isomerates. octane numbers. These bases generally consist of alkylates, (0014. In EP 697 033, a lead-free aviation gasoline is reformates and/or isopentane cuts, the latter being used in a described consisting of isopentane, alkylate, toluene, with a low concentration because of their high volatility. MON comprised between 90 and 93, additived with 4 to 20% 0003. But prior to their marketing, aviation gasoline of an aromatic amine in order to obtain a gasoline with an should satisfy other specific physico-chemical characteris MON greater than or equal to 98. tics, defined by international specifications. Thus aviation 00.15 EP 910 617 describes a mixture of aromatic amine gasolines should have and alkyltertiobutyl ether, and optionally of a manganese 0004 a low vapor pressure (less than 490 mbars) in compound which is added to the alkylate with a wide boiling order to avoid vaporization problems (vapor lock) or range, forming aviation gasoline. risks oficing increased by the low temperatures encoun (0016. In WO 02/22766 a lead-free aviation gasoline is tered in altitude; described, comprising a hydrocarbon compound which may 0005 a final distillation point of less 170° C., in order to be triptane associated with at least one liquid, Saturated, ali limit formations of deposits and their harmful conse phatic hydrocarbon compound (4 to 10°C.) and further com quences (power losses, deteriorated cooling); prising an alkyl ether (the thereby obtained base is not an 0006 good cold strength (absence of crystals down to AVGAS base). -58 C.) in order to prevent any blocking of the filters 0017 Even if these additives lead to an increase in the and conduits in altitude; octane number, this increase sometimes remains insufficient. 0007 a low sulfur content, presently limited to 0.05% Further, addition of these additives does not always meet the by weight, all these characteristics being grouped in the other requirements specific to aviation gasoline, such as heat ASTM D910-07 standard in effect at the filing date of ing value, vapor pressure and distillation range. the present application. 0018 Moreover, these different additives are not always 0008 Aviation gasolines are used on engines having good compatible with being respectful to the environment. For performances and frequently operating under a high load, i.e. example, aromatic amines widely used for improving the under conditions close to pinking. It is therefore required that octane number are all classified as toxic Substances, in the this type of fuel have very good resistance to self-ignition. case of absorption by inhalation or ingestion and especially 0009 For aviation gasoline, the motor octane number or on the skin. Methycyclopentadienyl manganese tricarbonyl MON is determined relatively to the operation with a slightly (MMT) is as for it indexed by EPA as an air pollutant, which lean mixture (cruising speed). With the purpose of guarantee may represent potential risks for humans. Oxygenated com ing this high octane requirement, the refiner generally pro pounds are presently not allowed in aviation gasoline com ceeds at the stage of the making of aviation gasoline, with the positions. addition of a organolead compound, and more particularly 0019. This is why other additive-free technical solutions tetraethyl lead (TEL). Now, like for gasolines for land have been proposed: vehicles, government authorities tend to lower the lead con 0020 EP 948 584 proposes an aviation gasoline with a tent, or even to Suppress this additive, because of its noxious MON above 98 which contains at least 30% by volume of character for the environment and health. Thus, firstly, reduc triptane and/or of 2.2,3-trimethylpentane. tion and then elimination of lead from the composition of (0021 EP 1359 207 describes a lead-free automotive gaso aviation gasoline become a goal to be attained in the short and line composition with an MON between 80 and 98 containing then in the medium term. from 5 to 25% by volume of triptane and/or of 2,2,3-trimeth 0010. The use of additives as a replacement for lead com ylpentane, from 5 to 15% of olefins, from 15 to 35% of pounds in order to improve the octane number, is well-known aromatics and 40 to 65% of C-C paraffins. for land vehicle gasolines, such as in patents EP 474342, GB 0022 EP 1 224 247 describes a lead-free gasoline which 2,114,596, U.S. Pat. No. 5,032,144 or U.S. Pat. No. 4,647, may notably be used as an aviation gasoline with an MON of 292. Insofar aviation gasoline is Subject to much more severe at least 80, with a RON comprised between 90 and 115 regulations than gasoline for land vehicles, for reasons of containing a C-C alkane with at least 4 methyl and/or ethyl US 2011/01 14536A1 May 19, 2011 branches. Preferably, the preferred gasoline further com 0036 a HV greater than or equal to 43.4, preferably prises triptane and/or 2.2,3-trimethylpentane. greater than or equal to 43.5, and advantageously greater than 0023 Now the addition in a significant amount of com or equal to 43.53 MJ/kg. pounds such as triptane and/or 2.2,3-trimethylpentane or 0037 a vapor pressure at 37.8°C. preferably varying from alkanes with at least 4 branches which are a very Small minor between 38 and 49 kPa preferably between 38.6 and 48.4 ity in usual oil bases stemming from refineries, and not only kPa. requires costly separation and purification processes for Syn thesizing these compounds but also generates for the refiner DETAILED DESCRIPTION OF THE INVENTION additional technical difficulties for storage and logistics for 0038. The first object of the invention is a lead-free avia these compounds generating costs above those generally tion gasoline composition without any oxygenated com obtained for formulating conventional aviation gasoline from pound, which comprises a mixture of hydrocarbon bases usually available in refineries. 0039 from 10 to 22% by volume of isopentane (2-methyl 0024 WO 04/044106 describes lead-free aviation gases butane), compositions with an MON ranging from 92 to 98 and con 0040 from 30 to 44% by volume of isooctane (2,2,4- taining from 10 to 90% by volume of at least one trimethyl trimethylpentane), pentane and at least one C-C paraffin. An example of a 0041 from 1.8 to 20% by volume of aromatics including 1 gasoline composition according to the invention with an to 10% by volume of toluene, MON of 95 comprises 59% isooctane, 8% toluene, 16% 0042 and containing not more than 1% by volume of isopentane, 24% by volume of alkylate and 16% of alkylate triptane (2,2,3-trimethylbutane) and not more than 4% by fraction other than isooctane. volume of 2.2,3-trimethylpentane. 0025 DE 19744 109 describes a lead-free gasoline com position for 2- and 4-stroke engines comprising 70-85% by 0043. This composition has volume of Cs isoparaffins, 17-19% by volume of Cs isopar 0044) an MON greater than or equal to 91, preferably affins, 2-4% of C isoparaffins and preferably not more than greater than or equal to 92, and less than or equal to 95. 0.5% of aromatics and 0.1% of benzene. This reference does 0045 an RON greater than or equal to 95, preferably not specify whether this gasoline is suitable as an aviation greater than or equal to 96, advantageously greater than or gasoline. equal to 98, and less than or equal to 100, 0046 an HV greater than or equal to 43.4, preferably greater than or equal to 43.5 and advantageously greater than SUMMARY OF THE INVENTION or equal to 43.53 MJ/kg, 0026. In order to meet these needs for a lead-free aviation 0047 a vapor pressure at 37.8°C. preferably varying from gasoline of the AVGAS type and without any oxygenated between 38 and 49 kPa preferably between 38.6 and 48.4 compound, the invention therefore aims at a novel lead-free kPa. aviation gasoline composition, intended for aircraft with pis 0048. In the sense of the present invention, by gasoline ton or reciprocating engines, made from hydrocarbon bases without any oxygenated compound is meant aviation gaso generally available in an oil refinery, having a high octane line not containing any oxygenated compound of the alcohol, number. The invention is notably directed to aviation gaso ester or ether type, except for isopropanol which may be used lines for which the LHV (low heating value) characteristics, as an anti-icing agent in an amountless than or equal to 1% of vapor pressure (VP) and distillation cut characteristics, the total Volume of the gases. observe the specifications retained for aviation gasoline 0049 Preferably, the aviation gasoline composition grades as described in the ASTM D910-07 standard, except according to the invention comprises for the lead content and the engine performances. 0050 from 14 to 22% by volume of isopentane, 0027. For this purpose, the object of the invention is a 0051 from 30 to 40% by volume of isooctane, lead-free aviation gasoline composition without any oxygen 0052 from 8 to 20% by volume of aromatics, ated compound, comprising 0053 including preferably from 4 to 9% by volume of 0028 from 10 to 22% by volume of isopentane, toluene. 0054 More advantageously, the aviation gasoline compo 0029 from 30 to 44% by volume of isooctane, sition according to the invention comprises 0030 from 1.8 to 20% by volume of aromatics including 1 0055 from 20 to 22% by volume of isopentane, to 10% by volume of toluene, 0056 from 30 to 32% by volume of isooctane, preferably 0031 and not containing more than 1% by volume of from 31 to 32%, triptane, not more than 4% by volume of 2,2,3-trimethylpen 0057 from 15 to 18% by volume of aromatics, preferably tane. including from 7 to 9% by volume of toluene. 0032. The aviation gasoline composition according to the 0058. The object of the invention is also a method for invention may be obtained in a simple and economical way preparing the composition defined earlier. from a mixture of hydrocarbon bases usually available in 0059. The method according to the invention consists of refineries. mixing at least one isopentane cut B1, at least one base of the 0033. This composition has the following features: aviation alkylate type B2 and at least one base of the aviation 0034 an MON greater than or equal to 91, preferably reformate type B3. greater than or equal to 92, and less than or equal to 95. 0060. The isopentane cuts and the aviation alkylate, avia 0035 an RON (research octane number) greater than or tion reformate bases are hydrocarbon bases easily available in equal to 95, preferably greater than or equal to 96, advanta refineries. geously greater than or equal to 98, and less than or equal to 0061 The method according to the invention consists of 100, mixing. US 2011/01 14536A1 May 19, 2011
0062 10 to 20% by volume of at least one isopentane refining operations (for example, distillation of crude oil, cut B1, which is a light base belonging to the family of catalytic cracking, hydrocracking, reforming, isomerization, the paraffinic hydrocarbons essentially consisting of Ca alkylation methods, ...) and/or synthetic hydrocarbons such and/or Cs isoparaffins and preferably comprising at least as notably those obtained by oligomerization of olefins, by 80% by volume, advantageously at least 90% by volume Fisher-Tropsch synthesis, by methods of the BTL (biomass to of C and/or Cs isoparaffins. According to a preferred liquid), CTL (gas to liquid) and/or GTL (gas to liquid) type embodiment, the base B1 comprises at least 90% by from materials of natural and/or synthetic origin, of animal Volume ofisopentane, and advantageously at least 95%; and/or plant and/or fossil origin. the isopentane bases B1 generally do not contain more 0068. Each base or cut entering the gasoline composition than 1% by volume of olefins; these light paraffinic according to the invention, i.e. the bases B1 to B3 as well as bases may for example stem from the lightest factions of any optional additional base, may have totally or partly been distillate produced by atmospheric distillation of crude Subject to a desulfurization and/or denitration treatment and oil and/or from alkane isomerization units: optionally to a dearomatization treatment at any stage of its 0063 62 to 88% by volume of at least one aviation elaboration. For example, bases may be used which have been alkylate base B2 essentially consisting of isoparaffins hydrotreated under more or less severe conditions (compris comprising 6 to 9 carbon atoms and preferably at least ing hydrodesulfurization and/or saturation of the aromatic 90% by volume ofisoparaffins comprising 6 to 9 carbon and olefinic compounds and/or hydrodenitration). atoms; aviation alkylates generally comprise at least 0069 Aviation gasoline according to the invention advan 95%, preferably at least 98.5% by volume of isoparaf tageously has a Sulfur content (measured according to ASTM fins, including at least 65%, preferably at least 70%, and D1266 or ASTM D2622) of less than or equal to 500 ppm, advantageously at least 80% by volume of Cs isoparaf preferably less than or equal to 100 ppm, or even less than or fins; according to a preferred embodiment, the alkylate equal to 50 ppm, et still even more advantageously less than bases B2 comprise at least 45%, preferably at least 48% or equal to 10 ppm. by Volume of isooctane, and advantageously at least 0070. In order to meet the characteristics for example set 30%, preferably at least 34% by volume of the other Cs by the ASTM D 910-07 standard, the aviation gasoline isoparaffins; these aviation alkylate bases may stem according to the invention may contain one or more additives, from different processes for treating crude oil, generally which one skilled in the art will easily be able to select from present in refineries; the bases B2 generally stem from the numerous additives conventionally used for aviation the process for alkylation of isobutane with light olefins; gasolines. Let us notably mention, but not in a limiting way, 0064. 1 to 22% by volume of at least one base of the additives such as antioxidants, anti-icing agents, antistatic aviation reformate type B3 essentially consisting of additives, corrosion inhibitors/lubricating power enhancers, (alkyl)aromatics (or simply aromatics); the reformate agents enhancing cold properties, tracer additives, coloring bases generally stem from the reforming of direct distil agents, detergents and mixtures thereof. lation gasoline and isopentane; aviation reformates gen 0071. These additives are generally incorporated into the erally consist of a hydrocarbon cut containing at least gasoline in amounts of less than 1,000 ppm. In the sense of the 70%, preferably at least 85%, by volume of aromatics present invention, if one or more of the applied additives and comprising toluene (generally from 35 to 75%, prefer incorporated into the gasoline contain one or more oxygen ably 45 to 70% by volume), of Cs alkylaromatics (gen atoms, the gasoline will be considered as 3. The aviation gasoline composition according to claim 1, TABLE I-continued compr1S1ng C-C7 n-paraffins O.8 from 20 to 22% by volume of isopentane: Aromatics from 30 to 32% by volume of isooctane; and B3 Aromatics 94.1 Benzene O.O6 from 15 to 18% by volume of aromatics. Toluene 49 4. The aviation gasoline composition according to claim 1, Xylenes 29.2 the Sulphur content of which measured according to the C1-C3 iso- and n-paraffins 4.6 ASTM D1266 or ASTMD2622° standard is less than or equal Cs isoparaffins O.6 to 500 ppm. 5. The aviation gasoline composition according to claim 1, 0074 5 mixtures of the bases B1 to B3 described earlier further comprising at least one additive selected from: Such as are made and the MON, RON. HV. VP parameters are mea antioxidants, anti-icing agents, antistatic additives, corrosion sured for the 5 mixtures noted as A to E. inhibitors/lubricating power enhancer, agents enhancing cold 0075. The results are grouped in Table 2 below. properties, tracer additives, coloring agents, detergents and mixtures thereof. TABLE 2 6. A method for preparing a gasoline composition compris A. B C D E ing mixing of: 10 to 20% by volume of at least one isopentane cut B1; B1 (volume %) 17 10 12 2O 18 B2 (volume %) 64 88 70 62 76 62 to 88% by volume of at least one aviation alkylate base B3 (volume %) 19 2 18 18 6 B2 essentially consisting ofisoparaffins comprising 6 to Isooctane (volume %) 31.5 43.4 34.5 30.6 37.4 9 carbon atoms; and MON-ASTM D2700 92 92.9 92.6 92.1 92.4 RON 98.3 95.6 98.5 97.9 96.3 1 to 22% by volume of at least one base of the aviation HV(MJ/kg)-ASTM D4529 43.47 44.41 43.53 43.56 44.17 reformate type B3 essentially consisting of one of alky VP (kPa) 46.3 43.8 38.9 48.1 48 laromatics and aromatic. 7. The method according to claim 6, further comprising in 1. A lead-free aviation gasoline (AVGAZ) without any addition to bases B1 to B3, at least one other bases or cuts are oxygenated compound comprising: added Stemming from at least one of Standard refining opera from 10 to 22% by volume of isopentane (2-methyl-bu tions and synthetic hydrocarbons, such as those obtained by at tane); least one of oligomerization of olefins, by Fisher-Tropsch from 30 to 44% by volume of isooctane (2,2,4-trimethyl synthesis, by methods of the BTL (biomass to liquid), CTL pentane); (gas to liquid) and GTL (gas to liquid) type from materials of from 1.8 to 20% by volume of aromatics including 1 to at least one of natural and synthetic origin, of animal and 10% by volume of toluene; and plant and fossil origin. containing not more than 1% of triptane (2.2,3-trimethyl 8. The method according to claim 6, further comprising at butane) and not more than 4% of 2.2,3-trimethyl-pen least one of toluene, isooctane and isopentane, added to the tane. mixture of bases B1, B2 and B3, and to the optional other 2. The aviation gasoline composition according to claim 1, bases. comprising 9. The aviation gasoline composition according to claim 1, from 14 to 22% by volume of isopentane: wherein the gasoline is an aircraft piston engine fuel. from 30 to 40% by volume of isooctane; and from 8 to 20% by volume of aromatics. c c c c c