Aviation Fuels

 

Hydrocarbons

 

olefins

naphthenes

paraffins

isoparaffins

aromatics

 

Any petroleum product is composed of a large number of different hydrocarbon compounds, and each of them has individual properties and characteristics. Almost all hydrocarbons present in fuels may be classified into five groups: the olefins, naphthenes, раrаffins, isoparaffins and aromatics. Compounds, within the same group have similar chemical, physical and combustion characteristics.

Olefins. Olefins are unsaturated hydrocarbon compounds. The general formula for the members of this group is CnH2n. Olefins are formed principally in the refining process called cracking. The olefins are the cause of much gum formation in gasoline; however, they possess very good combustion characteristics.

Naphthenes. Naphthenes are saturated, stable compounds even though the general chemical formula is CnH2n, the same as for the unsaturated olefins.

Paraffins. Normal paraffins are stable saturated compounds ha­ving the general chemical formula CnH2n+2. A large portion of any hydrocarbon fuel is composed of normal paraffins.

Isoparaffins. Isoparaffins are compounds possessing the same number of carbon and hydrogen atoms as a normal paraffin, but arranged in a different manner. The physical properties of this group are similar to those of normal paraffins.

Aromatics. The aromatics are unsaturated, but stable compounds. Benzene, C6H6, is the most characteristic member of the group, and all aromatics consist of some variation of the benzene ring. The general chemical formula for this group is CnH2n-6. This group has very desirable combustion characteristics for use in spark-ignition engines. Members of the group are often added to gazoline to produce high-octane fuels.

 

Exercise 2. Read the following chemical formulas:

C; H; O; CnH2n; C6H6; CnH2n-6; CnH2n+2; C8H6.1; C11.6H23.2

 

Exercise 3. Pick out the corresponding verbal definitions to the chemical signs and formulas. Translate them.

С – hydrogen

H – oxygen

S – carbon

O – sulfur

CnH2n – general chemical formula for aromatics

C6H6 – general chemical formula for paraffins

CnH2n-6 – general chemical formula for naphthenes

CnH2n+2 – chemical formula for benzene

 

Exercise 4. Give derivatives of the following verbs.

To saturate, to add, to ignite, to desire, to spark, to form, to refine, to combine, to compose, to process, to combust, to arrange.

 

Exercise 5. Pick out Ukrainian equivalents to following English words and word combinations.

Petroleum product частка

to be composed of такий самий як

hydrocarbon compounds смолоутворення

properties нафтопродукт

aromatics високооктанове паливо

saturated додавати

unsaturated бензол

stable бензин

refining process хочь

cause елемент

gum formation складатися з

gazoline властивості

to possess процес очищення

though необхідні характеристики

the same as різним чином

portion насичений

in a different manner не насичений

benzene стійкий

member двигун з іскровим запаленням

desirable characteristics причина

spark-ignition engines вуглеводневі сполуки

to add ароматики

high-octane fuel володіти, мати

 

Exercise 6. Complete the sentences. Translate them.

1. Basically, all aviation fuels are (продукти нафти).

2. Any petroleum product is composed of a large number of (вуглеводневі сполуки).

3. The olefins possess very good (характеристика згоряння).

4. A large portion of any hydrocarbon fuel is composed of (стійкі, насичені сполуки, що називаються парафінами).

5. Olefins are formed in (процес очистки, що називається крекінгом).

6. Compounds within the same group have similar (хімічні та фізичні характеристики).

7. Benzene is the most characteristic member of (групи ароматичних вуглеводнів).

8. Aromatics are often added to gasoline (для виробництва високооктанового палива).

9. The physical properties of isoparaffins are (такі самі як і у нормальних парафінів).

10. Aromatics have very desirable combustion characteristics (для використання в поршневих двигунах).

 

Exercise 7. Answer the questions to the text.

1. What are aviation fuels made of?

2. What is any petroleum product composed of?

3. How are all hydrocarbons present in fuels classified?

4. What are olefins?

5. What is the general formula for the olefins?

6. What formations in gazolines are though to be caused by olefins?

7. What group of hydrocarbons has the same general formula as olefins?

8. What group of hydrocarbons has the general chemical formula CnH2n+2?

9. What is the difference between the groups of normal paraffins and isoparaffins?

10. What do these two groups of hydrocarbons have in common?

11. What aromatic is the most characteristic member of the group of aromatics?

12. What is the general chemical formula for the aromatics?

13. What characteristics has the group of aromatics?

14. What representative of the group of aromatics has its chemi­cal formula C6H6?

 

Exercise 8. Read and translate the text.