history & development

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CHAPTER No . 2

HISTORY AND DEVELOPMENT

2.1 HISTORY AND DEVELOPMENT OF AVIATION GASOLINE:

The history of aviation gasoline, is as old as the history of powered flight. The earliest gasoline powered engines for air craft were essentially identical to those used in automobiles or motor cycles.
In the early days of aviation from 1903 to 1917 – 1918 almost any thing was used in an aeroplane engine that would enable it to operate. During this period the quality of Aviation Fuel was almost the same as that of regular motor gasoline for automobiles and in many cases inferior to it. No generally excepted specification were established for Aviation gasoline a such.
The some what expanded use of aeroplane in the first world war caused a definite interest in aviation fuel. After the loose of a no of them, believed to have being causted by motor failure due to improper fuel. The next important phase in the evolution of aviation fuel was the recognition of antiknock value and the development of suitable rating method to determine it. This took place in Thirties (30s), and during that period fuels of 87, 92 and finally 100 octane number were introduce and adopted for general use. It is expected that the antiknock values will be extended far above the present standard of 100 with resulting increases in power and operating efficiency.
Manufacturing methods have change radically owing to the increase quality of aviation fuel. With the development of hydrocarbon conversion processes for the production of high octane compounds the production of aviation fuel has become an industry with in an industry.
2.1.1 AVIATION FUEL BEFORE AND DURING FIRST WORLD WAR: Until the year 1916, aviation fuel or motor fuel, since the same type of material was used in both automobile and aeroplane engine, was a material of widely varying characteristics. The principle specification was that of gravity, and the gravity of the fuel was supposed to indicate its quality.
In a paper by Dean, the requirements for motor gasoline at that time were given below.

The gasoline should contain enough volatile material to ensure easy starting but not enough to cause excessive evaporation losses and danger in handling and storage.

It should not contain heavy material that would not vaporize and burn.

It should not form a residue in the engine.

It should be free from corrosive substances.

It should not have and its combustion products should not have a disagreeable odour.

It should be three of non combustible material such as water and acid.

In certain type of aeroplane, motor gasoline gave just as satisfactory performance result. In others the fliers reported hot running motor with the use of this type of fuel. An experimental gasoline composed of cyclohexane 70%, and benzene 30% seemed to be the most satisfactory for use in fighting aeroplanes. This fuel evidenced suitable operating characteristics in motors having a compression ratio as high as 7:5:1, and in some cases , this allowed a 10% power increase and a 1000 feet increase in ceiling. Other fuel distilled from selected crude oils were also satisfactory.
During the war manufacture of aviation fuel consisted of the following methods.

Distilling a straight run gasoline from a suitable crude oil source and adjusting the distillation range to the loosely specified limits.

Distilling a straight run gasoline and adding to it "casing head" or natural gasoline (adding natural gasoline to kerosene distillate).
Blending cracked gasoline to straight run gasoline with or without the addition of natural gasoline.
Blending straight run gasoline with benzol and alcohol.
Through close fractionation of a naphtha cut from selected crude oils, securing a 10^o boiling range fraction to be used un blended as a fuel.
Manufacturing cyclohexane synthetically and blending with it benzene.

The last three methods were in an experimental state at the end of the war and were use extensively.

It is interesting to note that cyclo hexane (octane no 83r, blending octane no. 99R) alcohol (octane no. Around 100) natural gasoline (octane no. 65 to 80) and straight run gasoline from napthenic and aeromatic crude oils were found for experience to give satisfactory performance.

2.1.2 AVIATION GASOLINE (1918 – 1930)

After the war, interest in the manufacture of aviation fuel from such materials as cyclo hexane ceased. This probably was due to the economic factor involved in the manufacture of such compounds. Also the demand was not sufficient to warrant extensive development at the time. The interest turned again to motor fuel and its quality, while aviation gasoline was left to shift for it self.

1920, Hill and Ean reported on the quality of gasoline marketed in the United States and compared the results of 1917 of survey with those of the 1919 the amount of cracked gasoline utilized almost doubled. Also the use of natural gasoline increased greatly owing to the widening of the volatility range of motor gasoline.

Refining companies, particularly the large ones, had begun to include in their shipping specification, colour, odour, un-saturation (% soluble in sulphuric acid), Doctor test gravity and distillation range. Under boiling point 20% point, 50% point, 90%, end point, and average boiling point.

In 1927 Government specification on two grades of aviation gasoline and one type of motor gasoline were published. In this set of specification the quality control were colour, corrosiveness, mercaptane sulphur content, volatility, stability and suspended matter. The appearance of copper dish residue test and the un-saturation test indicated that some importance was being given to the effect of gum formation by the fuel consumers. The volatility range of the aviation gasoline, both fighting and domestic grades, was narrower than that of the motor gasoline. The volatility of the fighting grade was greater than that of the domestic grade.

2.1.3 DEVELOPMENT OF AVIATION GASOLINE (1930 – 1942 )

Upto 1930, aviation was in its initial stages of its development. It was during this time that popular interest in aviation began and private flying become some what common. In the same manner the fuel requirements began to be sufficiently large to merit more than a cursery interest of the refining industry and attention was turned to aviation gasoline as a special product.

The principle difficulty in specifying a definite antiknock rating for aviation fuels was the lack of suitable test method. A great amount of experimentation was conducted on this subject and Edgar in 1927 advocated the use of normal heptane and Iso-octane as tentative reference fuel standards. The standard designation for knocking characteristics of the fuels for a time during that period was the HUCR or HUCP (The highest useful compression ratio or highest useful compression pressure).

The years of world war II also saw aviation gasoline reach its peak of development. Many grades of increasingly higher octane were formulated. World war II also saw the development of gas turbine engine (Jet engine) for use in aircraft. The advent of these Jet engine froze the further development of aviation gasoline. While large amounts are and will be consumed, further development of the fuel is unlikely. Aviation gasoline is one of the most complex, rigidly controlled products produced by oil refiners. A great number of physical and chemical properties must be control in order to produce a very consistent fuel. While specifications were quiet detailed they also contain a suitability requirement. This eliminates the possibility that some product that meets the "specs " but not adequate for use in aircraft could be marketed. Refiners are forced to consider where their product actually meets the intent of the specification not just the test results. Specification for aviation gasoline are by necessity quiet tight. Unlike other forms of transportation occupant safety in aviation is directly related to continuous power production. Thus, the fuel is a safety critical item in demands care and attention in its manufacture, distribution and storage. The various specifications have produce excellent quality fuels that perform well in a wide range of environment and applications.

2.2 HISTORY AND DEVELOPMENT OF JET FUEL:

The history and development of Jet fuel start from world war II with the development of Jet engine. The advent of these jet engines froze the further development of aviation gasoline.

The development of Jet and turbine air craft engines caused a rapid increase in jet fuel manufacture so that that the middle distillate portion of petroleum was in great demand for distillates, diesel fuel, jet fuel and rocket fuel. Although a kerosene like material (JP – 1 grade) was first used and a similar high boiling fuel (JP – 5 ) is still supplied in limited quantities. The main current fuels (JP – 3 and JP – 4 ) are wide boiling range materials which extends through gasoline and kerosene.

Production has been almost totally straight run material but there are indications that small amounts of cracked material and heavy alkylates or reformats can be incorporated in the event of war, such materials will have to be tolerated. The low freezing point of –76^oF is a difficulty in meeting specifications, and if certain naphthenic or aeromatic crude oils are processed the gravity requirements becomes limited.

Through out the world specification DERD-2482, which is an eastern hemisphere kerosene, is used almost exclusively (1956), but some air-lines require a freeze point of –50^oF rather than –40^oF.

The properties and characteristics of jet fuels, 1952 – 1956 are given below in the table 2.1.

The JP – 8 is like Jet – A1 with a full additive package. The USAF plans conversion to this product by the year 2000.

Table 2.1

Fuel	No of samples	API gravity	Dist. Temp. ^oF 10% 50% 90% evap. evap evap			Reid vapor pressure	Sulfur wt%	Aromatics vol.%	Gum existent steam-jet
Avg. Grade JP-1: 1952…	3	42.3	338	368	421	…..	0.057	14.3
Avg. Grade JP-3: 1952… 1954… 1956…	6 4 3	52.5 56.5 55.6	166 160 157	316 265 272	433 421 430	6.0 5.7 5.6	0.081 0.089 0.063	14.7 10.3 9.3	1.5 1.1
Avg. Grade JP-4: 1952… 1954… 1956…	24 23 31	50.5 51.5 52.4	222 216 217	332 319 317	430 425 409	2.6 2.6 2.6	0.075 0.080 0.054	11.9 11.3 10.5	0.6 0.8
Avg. Grade JP-5: 1953… 1955… 1956… 1956…	1 3 1 1	37.3 39.8 37.7 39.3	397 392 389 386	432 428 418 422	491 485 468 472	0.5 …. …. 0	0.46 0.167 0.26 0.18	8.3 12.0 10.0 12.8	2.0 0.9 1.0 0.5

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