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PHYSICAL PROPERTIES OF PETROLEUM





 

The colour of petroleum varies from light yellow to red, while some very dark grades are opaque. The higher the specific gravity, the darker the oil.

The nature and composition of crude oil usually determines its odour. Unsaturated hydrocarbons, sulphur and certain nitrogen compounds are responsible for disagreeable odours. Crude petroleum from Russia, Rumania and California has an aromatic odour. Pennsylvania petroleum has an agreeable gasoline-like odour. Other oils vary in odour depending on the quantity of light hydrocarbons present in the oil, and of the impurities present. The petroleum from South Texas and Mexico has a strong disagreeable odour, due to hydrogen sulphide and other sulphur compounds. Petroleum is lighter than water. The specific gravity is influenced by physical factors and by the chemical composition of the crude oil. It varies from 0.7684 to 0.992.

The viscosity, or the measure of the resistance to flow, is an important factor with lubricating oils. It is usually stated in terms of the time¹ necessary for a definite volume of oil at a definite temperature to flow through a small opening. The actual work is carried out in an instrument known as a viscosimeter, of which there are several standard makes in use at the present time. Crude oils are quite different in viscosity. Some are very mobile, while others, like Mexican crude, are quite viscid. Oils composed of hydrocarbons belonging to the series CnHn2-2 and CnHn2-4 are viscous. Heavy petroleum in general is composed to a large extent of these hydrocarbons. The viscosity increases with the density.² The viscosities of oils of the same specific gravity but from different sources, are not always the same. This is due to the difference in chemical composition.

Notes

¹ It is usually stated in terms of the time – она обычно определяется промежутком времени

² increases with the density – увеличивается с увеличением плотности



 

PETROLEUM

Colour, odour, specific gravity, and viscosity are the main physical properties of petroleum. Another important determination made in connection with petroleum products is that of the flash and burning points. The flash point may be defined as the temperature at which the vapours arising from the heated oil will ignite with a flash of very short duration, when a small flame is passed over the surface. This is of the utmost importance, as it indicates the temperature at which oil will ignite. The specific heat of the hydrocarbons in each series decreases with increase in molecular weight. The heat of vaporization decreases with increase in molecular weight.

Crude oils differ markedly in their boiling points and in the amount of distillate which is obtainable at definite temperatures. The boiling point of the crude oil will depend largely on the hydrocarbons. Petroleum of low specific gravity will usually contain a larger proportion of the more volatile hydrocarbons, whereas in a crude oil of high specific gravity, high boiling hydrocarbons generally predominate.

 

CRACKING

 

The pyrogenic decomposition of petroleum with the consequent breaking up of the molecules and the production of both lighter and heavier hydrocarbons is termed “cracking”. In the terminology of the industry “cracking processes” are those designed to utilize the above decomposition for the conversion of heavier oils into the more valuable gasolines and naphthas.

All petroleum hydrocarbons have a characteristic temperature above which the cracking reaction takes place. This temperature varies for the different cuts from a given crude oil and for similar cuts from different crude oils.

Historically, cracking dates back to the early years of the nineteenth century when the formation of volatile compounds by cracking animal oils was discovered. These early discoveries were regarded merely as scientific phenomena of no commercial value. In the early days of the petroleum industry attention was paid to increasing the yields of illuminating oils, then the most valuable constituent of the crude. Since these early days the demand for gasoline has resulted in many different processes.



The systems in commercial use may be broadly classified as cracking in the vapour phase and cracking in the liquid phase. Cracking in the vapour phase consists in vapouring the oil and then producing the reaction by the addition of heat, or of heat and pressure together. High gas loss and difficulty with apparatus tended to retard the development of this type of process. Consequently, the liquid phase processes received a tremendous impetus, and the great majority of commercial installations are of this type.

Lesson Four

NATURAL GAS

I. Words and expressions to be remembered:

1. stream - поток

2. volume - объем

3. quantity - количество

4. inversely proportional - обратно пропорциональный

5. to exert upon - оказывать (давление)

6. constant - постоянный

7. inflammable - горючий

8. to define – определять

9. to occupy – занимать

10. directly proportional – прямо пропорциональный

11. to exist – существовать

12. to occur - встречаться

13. marsh – болото

14. amount - количество

15. vapour - пар

16. methane – метан

17. ethane - этан

18. propane - пропан

19. butane - бутан

20. water vapour - водяной пар

21. сarbon dioxide - двуокись углерода

22. hydrogen sulphide - сероводород

23. helium - гелий

24. carbon disulphide - сероуглерод

 

II. Read and translate the following word combinations:

natural gas, inflammable gas, solid gas, atmospheric conditions, weather conditions, hard conditions, pressure, absolute pressure, atmospheric pressure.

 

III. Translate the words of the same root:

nature – natural, industry - industrial, gas - gaseous, differ – different - difference, exist - existence, define - definition.

 

IV. Translate into Russian paying attention to the Complex Subject with the Infinitive construction:

1. This element is said to occur in the earth’s crust.

2. Natural gas is considered to be inflammable.

3. The volume is assumed to be inversely proportional to its absolute pressure.

4. Natural gas is consideredto be a valuable raw material.

5. It is likely to contain one or more of the following components.

 



V. Read and translate the text:

Natural Gas

 

Natural gas is a complex mixture of hydrocarbons and nonhydrocarbons that exists as a gas at atmospheric conditions. It is inflammable and occurs in the earth's crust with or near accumulations of crude oil. Its principle component is methane. This is a compound which is often found in nature in marshy places, so it is sometimes called “marsh gas”. There are also smaller amounts of ethane, propane, butane in natural gas.

Any sample of natura1 gas is likely to contain one or more of the following components: water vapour, nitrogen, carbon dioxide, hy­drogen sulphide, helium, carbon disulphide.

The volume occupied by a quantity of natural gas is inversely proportional to the absolute pressure exerted upon it, if temperature is held constant.

The volume is directly proportional to its absolute temperature if the pressure is held constant. Accurately to define a volume of gas it is necessary to define the conditions of pressure and tempera­ture at which it is measured.

Natural gas is a valuable raw material. It is also widely used as fuel for domestic and industrial needs.

 

VI. Answer the questions to the text:

1 .What is natural gas?

2. Where does it occur?

3. What components does it contain?

4. What does the accurate definition of the gas volume depend on?

5. What is the main use of natural gas?

 

VII. Translate into English:

сложная смесь, существовать, находиться, горючий, условие, содержать, объем, занимать, оказывать давление, необходимый, постоянный, измерять, ценный.

 

VIII. Use the proper words and word combinations:

1. Natural gas exists as gas at ... (atmospheric pressure, high temperature, atmospheric conditions).

2. It occurs in the … (earth's crust, atmosphere, cosmic space).

3. Natural gas contains the following components: water vapour, nitrogen, carbon dioxide, … (iron, copper, helium), etc.

4. It's main use is for… (lighting, heating, cooling).

 

IX. Translate into English:

1. Природный газ - ценное углеводородное сырье.

2. Его используют не только как топливо, но и как сырье для нефтеперерабатывающей промышленности.

3. Основные компоненты природного газа: метан, пропан, бутан, этан.

4. В его состав также входят водяной пар, азот, двуокись углеводорода, гелий и т.д.

5. Чтобы определить объем газа, необходимо знать давление и температуру.

 

X. Speak on:

1. Natural gas composition.

2. The proper definition of its volume.

3. Application of natural gas.

 

 

Lesson Five

 

SOLID GAS

 

I. Words and expressions to be remembered:

1. source - источник

2. deposit - залежь

3. state - состояние

4. to exceed - превышать

5. regular natural gas - обычный природный газ

6. to resemble – напоминать, быть похожим

7. non-transparent - непрозрачный

8. sedimentary – осадочный

9. mantle - мантия

10. sub-zero - ниже нуля

11. volume - объем

12. although - хотя

13. to dissolve - растворять

14. to infer - выводить, подразумевать

15. to estimate – исчислять, оценивать

16. agreement - соглашение

17. to convert - превращать

18. to achieve - достигать

19. spirit solution - спиртовой раствор

20. to supply - поставлять, снабжать

21. possible - возможный

22. reserve – запас, месторождение

23. visually - визуально

24. the Earth’s crust – земная кора

25. according to – в соответствии

26. salt solution – соляной раствор

27. site – место, площадь (зд. месторождения)

28. introduction – введение

29. to raise – повышать

30. antihydrate – антигидратный

31. to exist – существовать

32. scale - масштаб

 

II. Read аnd translаtе word combinations:

а 1аrgе deposit, a large source, free state, solid state, liquid state, sub-zero, over-zero, slightly over-zero, large volume, inferred deposits, according tо scientific calculations, practical realization, principle agreement, to convert into other states, large area, large scale, industrial scale.

 

III. Translate the words of the same root:

agree – agreement – agreeable - disagreeable; free - freely - freedom; realize - realization, exploit - exploitation - exploiting; use - usage; science - scientist - scientific; exist - existence; main - mainly; achieve - achievement; important - importance; calculate - calculation - calculated.

 

 

IV. Find the synonyms:

deposit, slightly, utilization, to resemble, to calculate, reserve, usage, a little, large, huge, to look like, estimate.

 

V. Translate into Russian paying attention to the underlined predicates:

1. Natural gas exists not only in a gaseous but in a solid state as well.

2. One volume of hydrate may contain up to 200 volumes of gas.

3. The scientists have come to the conclusion.

4. Soviet geologists have established huge deposits of natural gas.

5. Solid gas should be converted into free state.

6. They form in the Earth’s crust.

7. Only one deposit is being exploited.

8. It has been supplying gas to Norilsk.

 

VI. Translate the follоwing words:

источник, месторождение, возможный, объем, напоминать, состояние, растворять, превращать, достигать, поставлять, снабжать, превышать.

 

VII. Read and translate the text and answer the questions:

 

Solid Gas

 

Gas hydrates, or solid gas are a new large source of heat energy and chemical raw material on our planet.

In our country they have already started the exploitation of these deposits and it is possible that in the near future they will become an important source of hydrоcаrbon raw material.

The hydrосаrbon reserves in the state of gas hydrates exceed several times the summary reserves of coal, oil, regular natural gas on our planet.

Visually they resemble non-transparent ice. They form in the Earth's crust in its upper sedimentary mantle, when ethane, butane, propane and other gases combine with water under pressure of 0 to 250 atmospheres and under sub-zero or slightly above-zero temperatures (up to 20 degrees Centigrade). One volume of hydrate may contain up to 200 volumes of gas, although under normal conditions it is difficult to dissolve more than 4 cubic meters of natural gas in a cubic meter of water.

According to scientific calculations, the inferred reserves of solid gas in the sea and ocean can be estimated at 1018 с.m.

The most difficult part in the practical realization of the huge perspectives for the usage of solid gas is the exploitation of hydrate deposits. The scientists have come to the main principle agreement — gas should be converted into its free state at site. This can be achieved by reducing the pressure, by raising the temperature or through introduction of antihydrate liquids - salt or spirit solutions. Soviet geologists have discovered nearly 30 areas where solid gas could exist, but only one of them is being exploited in the North of Krasnoyarsk Territory.

For many years it has been supplying gas to Norilsk.

During the next years we maу speak about exploiting gas hydrate deposits on the industrial scale.

 

VIII. Answer the questions:

1. What is a new large source of heat energy?

2. What country has already started the exploitation of these deposits?

3. Ноw large are gas hydrates reserves on our planet?

4. What do they look like?

5. Under what conditions do they form?

6. What is the most difficult part in the practical realization for the usage of solid gas?

7. What conclusions have the scientists come to?

8. How many areas rich in gas hydrates have the Soviet geologists established?

9. How many of them are being exploited now?

 

IX. Translate into English:

1. Твердый газ - не только новый источник энергии, но и ценное сырье.

2. Внешне он напоминает непрозрачный лед,

3. Один объем гидрата может содержать до 200 объемов газа.

4. Советские геологи открыли более 30 месторождений твердого газа.

5. Наша страна начала эксплуатацию месторождений твердого газа.

6. Самое трудное в использовании твердого газа - эксплуатация его месторождений.

 

X. Translate into Russian:

1. Gas hydrates were discovered by H. Davy in 1811 and the early classical contribution to our knowledge of gas hydrates was made by Fагаdау, Rooseboom and others.

2. Russian scientists have detected about 30 pools that could contain natural gas hydrates.

3. Тhе maximum depth of hydrate formations ranges from about 500 meters near the southern end of Yamal Peninsula to over 1200m. in the Viluy basin and over 1600 meters towards the lower reaches of the Lena River.

 

XI. Speak on:

1. The conditions under which solid gas has been found.

2. The exploitation of hydrate deposits.

 

 

Lesson Six

 

 








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