The composition of crude oil
The composition and the physical properties of crude oil differ widely to where it was produced. It is characterized and classified by the chemical constitution of its main components and by its physical properties. It consists of paraffins, naphthenes, and aromatics (ароматические соединения) in various proportions. It also contains many impurities, sulphur and oxygen compounds.
The compounds composed of hydrogen and .carbon are called hydrocarbons.
Hydrocarbons at normal temperatures and pressures may be gaseous, liquid or solid according to the complexity of their molecules. The natural deposits are correspondingly gaseous, liquid or solid depending on the relative proportion of the various hydrocarbons present in the mixture.
The physical operations of refining, such as vaporization, fractionation, and cooling depend on the properties of the hydrocarbons because they constitute the bulk of the oil, but the chemical operations, such as treating and filtering depend on the presence of sulfur, oxygen and nitrogen compounds and, to some extent, on the small amounts of reactive hydrocarbons that may be present. The oxygen is often combined in the form of naphthenic acids. Nitrogen is most often found in naphthene-base oils. Sulfur may be present too. Some of sulfur compounds are not found in crude oil, but they are produced from other compounds during distillation and refining. Sulfur compounds are particularly troublesome because they are usually foul- smelling and some of them are corrosive. They are to be removed.
Most crude oils, although liquid as such, contain gaseous and solid hydrocarbons in solution. The gases come out of solution either on the release of pressure as the crude oil is produced or during the first stage of refining, and contribute to the total natural gas production.
2. Ask 10 questions оn the text (составьте 10 различных вопросов по содержанию текста): General (общий) — 2, Special (специальный) — 3, Alternative (альтернативный) — 3, Disjunctive (разделительный) — 2:
3. Determine the tense form of the verbs and translate the sentences into Russian (определите время глагола-сказуемого и переведите предложения):
a. New construction materials have been used while building this bridge.
b. Why are you using such figures in your report?
c. I was warned about the meeting two weeks ago.
4. Переведите предложения на русский язык, принимая во внимание место предлога при бессоюзном подчинении:
a. The place she described in her letter appeared really beautiful.
b. The year he was born in was a leap year.
c. The law I am speaking about applies to gases.
5. Translate the sentences into Russian. Mind the difference in the translation of the Objective Infinitive Construction and the Subjective Infinitive Construction (переведите предложения на русский язык, учитывая разницу в переводе инфинитивных конструкций):
a. Economists consider natural resources to be the third factor of production.
b. We want our daughter to enter the Economy College.
c. This Institute is known to train good specialists.
d. Victor is said to graduate from the institute and work in a good firm.
6. Translate the sentences into Russian (переведите предложения на русский язык):
a. If he had known about the exam earlier he would have prepared better.
b. You should better buy a present for your wife’s birthday beforehand.
c. If I were you I should visit him immediately.
Наталья
Московский Энергетический Институт
Работу выполнила очень быстро, отзывчивый исполнитель! Огромное спасибо
Юлия
РОСИ
Огромное спасибо за работу! Всё выполнено в срок, учтены все пожелания. После проверки пре...
Маргарита
БГИ
Спасибо большое Екатерине за выполненный досрочно заказ в полном объёме, а главное такое ...
Ирина
МГПУ
Заказываю работы не первый раз у Екатерины и все работы сданы на отлично. Спасибо вам?