Aviation Fuel

 

AVIATION FUEL

Mega Suci Lestari (151411017) Listya Ra!aya"ti (151411015)

 

I"tr#$ucti#"  The term aviation fuel, as used in this text, is a collective term that includes aviation gasoline and aviation gas turbine fuel as well as various types of jet fuel. Aviation fuels consist of hydrocarbons, and sulfurcontaining as well as oxygen-containing oxygen-containing impurities are limited strictly by specication. Composition specications usually state that aviation fuel must consist entirely of hydrocarbons except for trace amounts of approved additives.

 

 The two basic types of jet fuels in general use are based on erosene !erosene-type jet fuel" and gasoline !naphtha" !gasolinetype jet fuel". #erosene-type jet fuel is a modied development of the illuminating originally used range in gas and turbine engines. $asoline-type jeterosene fuel has a wider boiling includes some gasoline fractions. %n addition, a number of speciali&ed fuel grades are re'uired for use in high-performance military aircraft

 

%RO&U'TION AN& %RO%ER %RO%ERTIES TIES  Aviation gasoline, for aviation piston engines, is produced from  petroleum distillation fractions containing lower-boiling hydrocarbons that are usually found in straight-run naphtha.  Aviation turbine fuels are manufacture manufactured d predominan predominantly tly from straight-run erosene or erosene-naphtha blends in the case of wide-cut fuels that are produced from the atmospheric distillation of crude oil. (traight-run erosene from low-sulfur !sweet" crude oil will meet all the re'uirements of the jet fuel specication without further renery processing, but for the majority of feedstocs, the erosene fraction will contain trace constituents that must be removed by hydrotreating !hydroning" or by a chemical sweetening process

 

TEST METO&S (pecications covering the various grades have drawn up by a number of bodies, and these have reissued from time to time as engine re'uirements changed. )o signicant changes have now occurred in

been been have these

specications for a number of years, except for the gradual reduction in the number of grades covered.  The re'uirem re'uirements ents for jet fuels stress a di*ere di*erent nt combination of properties and tests than those re'uired for aviation gasoline !A(T+ -//". The same basic controls are needed for such properties as storage stability and corrosivity, but the gasoline antinoc tests are replaced by tests directly and indirectly controlling characteristics.

energy

content

and

combustion

 

1 Aci$ity Acidity is a property usually found in lubricating oil !A(T+ 0,A(T+ -120, A(T+ -3331, A(T+ -/224, %5 31, %5 22, %5 03"6 acidic compounds can also be present in aviation turbine fuels either because of the acid treatm treatment. ent. %n the test method for the determination of the acidity in an aviation turbine fuel !A(T+ -3707, %5 3/0", a sample is dissolved in a solvent mixture !toluene plus isopropyl alcohol and a small amount of water" and under a stream of nitrogen is titrated with standard alcoholic potassium hydroxide to the color change from orange in acid to green in base via added indicator  pnaphtholbenzein naphtholbenz ein solution.

 

* A$$iti+es  The various appro approved ved additives for jet fuels include oxida oxidation tion inhibitors to improve storage stability, copper deactivators to neutrali&e the nown adverse e*ect of copper on fuel stability, and corrosion inhibitors intended for the protection of storage tans and pipelines. Additives may be included for a variety of reasons, but in every case the specications dene the re'uirements as follows8 . +andatory8 must be present between minimum and maximum limits. 7. 5ermitted8 may be added up to a maximum limit. 3. 9ptional8 may be added only within specied limits. 0. )ot allowed8 additives not listed l isted in the specications.

 

, 'a-#ri.c Va-ue (eat #/ '#!usti#")

 The heat of combustion !A(T+ -704, A(T+ -04/" is a direct measure of fuel energy content and is determined as the 'uantity of with heatoxygen liberated the combustion of a unit 'uantity of fuel in aby standard bomb calorimeter.  This fuel pro property perty a*ects the economics of engine performance, and the specied minimum value is a compromise between the and con:icting re'uirements of maximum fuel availability good fuel consumption characteristics.

 

4 '#!#siti#"  This method is applied applied to data related related to the volume percent saturates, olens, and aromatics in materials that boil below 3/;C !44;or volume basis. ?ariation in density is controlled within broad limits to ensure engine control. @oth fuel specic gravity and caloric value vary somewhat according to crude source, paranic fuels having a slightly lower specic gravity but higher gravimetric caloric value than those from naphthenic naphthenic oils. ensity used in fuel calculations, because weight crude or volume fuel is limitations !orload both" may be necessary according to the type of aircraft and :ight pattern involved.

 

3 F-as %#i"t

 The :ash point point test is a guide to the re ha&ard ha&ard associated associated with the use of the fuel6 the :ash point can be determined by several test methods, and the results are not always strictly comparable.  The minimum :ash :ash point is usually dened dened by the Abel Abel method !%5 24", except for high-:ash erosene, where the 5ensyB+artens method !A(T+ -13, %5 30" is specied. The TA$ method !A(T+ /" is used for both the minimum and maximum limits, whereas certain military specications also give minimum limits by the 5ensyB+artens method !A(T+ -13, %5 30". The Abel method !%5 24" can give results up to 7B3;C !3B/;min while continuously being illuminated by a light source

 

 6"#c a"$ A"ti"#c  

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 The various fuel grades are classied classied by their antinoc 'uality charactercharacteristics as determined in single-cylinder laboratory engines. #noc, or deto-nation, in an engine is a form of abnormal combustion where the air>fuel charge in the cylinder ignites spontaneously in a locali&ed area instead of being consumed progressively by the spar-initiated :ame front.  The antinoc ratings of aviation gasoline are determined in standard laboratory engines by matching their performance against reference reference blends of pure iso-octane and n-heptane.  The higher grades fuel ar e thus classied by their specied antinoc ratings under both of sets ofare test conditions.

 

8 %#ur %#i"t 

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 The pour point of a petroleum petroleum product is an index index of the lowest tempera-ture at which the product will :ow under specied conditions. %n the original !and still widely w idely used" test for pour point !A(T+ -12, %5 /", a sample cooled at a specied rate and examined at intervals of 3;C !/.0;