US2211732A - Motor fuel - Google Patents

Description

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' 5.0 Such mixtures j are Patented Aug. 13, 1940 UNITED STATES PATENT OFFICE Moron FUEL Alexander N. Sachanen and Alfred. W. Francis, Woodbury, N. J.. assignors to Socony-Vacuum Oil Company, Incorporated, New York, N. Y., a corporation of New York Application February 1o, 1939, serial N0.`255,so2

3 Claims. (Cl. 44--9) This invention is directed to the production of motorfuel for high compression internal combustion engines, particularly aviation fuels. It is particularly directed to the provision of 5 motor fuels `combining the properties of high inherent anti-knock, quality, high susceptibility` vto `improvement of anti-knock quality'by the addition of tetra-ethyl lead," and having balanced 'distillation characteristics suitablel for proper vl0 utilization in 'high efficiency engines.

high 'temperatures without catalyst, with or without high pressure, or Yunder slightly flower temperatures in the presence of catalysts such as adsorptive contact masses, to give mixtures of y alkyla'ted benzenes. Where the process is one of treatment of a mixture of gasoline and benzene, the resultingproduct is a mixture of 'gaso line and. various alkyl benzenes not capable of separation by distillation. In this mixture there are .present not only `all of the higher boiling `fra`ctions jof the gasoline but also the various alkyl `benzenesv which boil in the same boilingA range as the higher 4boiling fractions of the gasoline. Asfwill be pointed out later, such mixtures areundesirable. When the process is con- 40 'ducted solely for-the production of alkyl benzenes as inthe later examples noted above, there is produced` a mixture of alkyl benzenes boiling in the same boiling range as the higher boiling .4 constituent of gasoline. When thel products of there are present in thenal mixtureboth the 1.', higher .boiling constituents of gasoline andthe Qalkyl benzenes whichboil in the same range of temperature.

not desirable forA several reasons. For onething, to insure proper car-- buretion and combustion of motor fuel, it is well known that the distribution of products in this boiling range should be uniform. A pr epon ler' v f ance vof'either light or heavy material leads to such processes are mixed withordi'nary gasoline,

uneven carburetion and to uneven burning. This 1s recognized by users and therequirernent is reflected in specifications which requirereasonable distribution of material across the entire boiling range of the fuel. This'is usually arrived 5 at by specifying that some given ,percent yof distillate shall be recovered at not more than .FJ for several points in the boiling range. Atypical distillation specificationk for a gasoline for aviation engine use is as follows: 'l0

Distizzation' 'characteristics Percent recovered in receiver F. maximum 311. Percent recovered.. 96% minimum. Percent loss Percent residue..

2% maximum.

This is the distillation range vspecification adopted 4for a number of fuels of varying octane number by American Airlines, as shown by 25 Table I-Domestic (U. S.) Aircraft Fuel Specifcationsin Aircraft-Fuel Specifications, Pres,- entand Future by Hubner,'Egloi and Murphy, National Petroleum NeWs,.July 28, 1937.

vThe realrequirement of'such specifications an may be noted by reference .to the drawing attached to this specification, wherein curve l showssuch a specification and 'curves 23, 5 show variousfuels later described. The important feature of the specification, as shown by,.curve 35 l is the relativeamountsof low boiling Yand high boiling constituents, as'shown by its gradual rise or slope. `This specification is typical only and other fuels may vary from thisin 'degree or slightly in kind. For example, a lighter fuel 40 of gthe same ykind would be shownby-displacing. curve I downwardly without changexof slope, or

' a heavier o ne by displacing curve l upwardly.

To specify fuels somewhat higher in light constituents,`as` may be preferred by some foravi- 45 ation' purposes, the ycurve I could 'be changed somewhat inf-slope, falling Va little llower at the low boiling end and rising a little higher on the high 'boiling end, yet without material increase in end point. 50'

' In contrast with curve i, curve 2 shows an exceedingly poor fuel. This' 'fuel `is entirelyy too high in -boiling range and not suiciently rich Yin low boilingfmaterial. This curve represents the' distillation range of a mixture of alkyl 65 2% maximum. 20

benzenes such as may be produced by the processes hereinbefore described.

Curve 3 shows an equally poor fuel, entirely too rich in light material, although some of its heavy material is relatively high boiling. 'I'his is a commercial casinghead gasoline of 320 F. end point.

Curve 4 shows what may be achieved by a blend of equal proportions of the fuel of curve 2 and the fuel of curve 3. The resulting blend, although it possesses a low initial boiling point, is entirely deficient because it has too much high boiling point material resulting from the simultaneous presence of the heavy constituents of both fuels. Blending in various proportions other than 50-50 will not serve to remedy this. The fuel may be highly antiknock, but will be carbureted so poorly and unevenly that this property cannot be made use of. Fuels arising from the simultaneous production of gasoline and alkyl benzenes will have similar characteristics for the same reasons.

However, if we take from the fuel of curve 2 only those portions of boiling range Within that of the desired fuel, discarding the remainder, and

. take from the fuel of curve 3 only those portions of boiling range below the selected portion of the fuel of curve 2, discarding the remainder, we may blend the two selected fractions to give a fuel having proper boiling characteristics. For example, curve 5 shows a blend of 50 per cent of casinghead gasoline comprising that fraction of the fuel of curve 3 boiling below 210 F., and 50 per cent of alkyl benzenes which are the portion of the fuel of curve 2 boiling up to 300 F. Note that the curve 5 is regular in form, and that because there is substantially no overlap in the boiling range of the constituents, it can be shifted in slope by changes in proportion of those constituents.

Of particular interest are some other properties of blends made of fuel constituents of selected properties as disclosed herein.

Acid heat test Specification Shall be not more than 20 F. Fuel of curve 5 7 F.

'Ihe acid heat test is based on the heat generated by shaking a specied amount of fuel with C. P. sulphuric acid of 1.83/1.84 specific gravity and is a measure of undesirable and unstable (unsaturated), material present.

Lead susceptibility Motor method octane number Fuel of curve 5, 85,1; fucl-I-B cc. lead, 96.8; increase, 11.7 The novel blend is thus seen to retain a high lead susceptibility, a. feature which has not heretofore been thought possible for high octane number aromatic blends containing as much as 50% aromatic hydrocarbons.

Within the limits herein taught, this disclosure may be applied to the blending of alkyl benzenes with gasoline of any origin, be it casingbead, straight run, or cracked. The method is particularly valuable when utilized for the production of aviation gasoline of unusually high quality from vapor phase catalytically cracked gasoline. With a material of this type, particularly with a material such as that produced by the so-called Houdry process, wherein gas oil is catalytically cracked at temperatures of about 875 F. in the presence of a granular catalyst composed essentially of alumina and silica, aviation gasolnes may be produced having nearly octane value by the motor method, by the addition of a comparatively small amount of lead uid to a properly produced blend of cracked gasoline and alkyl benzenes.

Particularly desirable aviation fuels may be made by taking the portion of such catalytically cracked gasoline boiling below about 220 F. and blending with it a mixture of alkyl benzenes having an end point somewhat lower than that of the desired aviation gasoline, for example about 300 F.

We claim:

l. A motor fuel having distillation characteristics of an aviation gasoline and a smooth boiling range comprising a mixture of alkyl benzenes boiling above about 220 F. and a gasoline fraction boiling below about 220 F.

2. An aviation motor fuel characterized by high anti-knock value, high lead susceptibility, and balanced distillation range characteristics comprising a blend of two ingredients, one of which is a mixture of alkylated benzenes, the other of which is a low boiling material of petroleum origin' substantially all of which has a boiling range below that of the alkylated benzene mixture.

3. A motor fuel characterized by high inherent anti-knock value, balanced distillation range and high lead susceptibility comprising a blend of two ingredients, one of which is a mixture of alkylated benzenes having a boiling range terminating at approximately the end point of an aviation fuel, the remainder being the portion boiling below about 220 F. of a cracked gasoline produced by subjecting gas oil to catalytic cracking at a temperature of about 875 F. in the presence of a catalytic contact mass composed essentially of alumina and silica.

ALEXANDER N. SACHANEN. ALFRED W. FRANCIS.

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