III. Find words that mean the following.
1. one of the portions of fractional distillation having a restricted boiling range
2. middle-distillate petroleum fraction with a boiling range of about 350°-750° F, usually includes diesel fuel, kerosene, heating oil, and light fuel oil
3. a process for thermally converting and upgrading heavy residual into lighter products and by-product petroleum coke
4. the chemical addition of hydrogen to a material in the presence of a catalyst
5. a process used to convert heavier feedstock into lower-boiling, higher-value products.
6. an upgraded naphtha resulting from catalytic or thermal reforming.
7. a reaction that catalytically converts straight-chain hydrocarbon molecules into branched-chain molecules of higher octane number.
8. a family of unsaturated hydrocarbons with one carbon-carbon double bond and the general formula CnH2n.
F
igure
4. Two-stage hydrocracking
Figure
5. Polymerization process
.
IV. Translate the following sentences into English.
1. Нефтеперерабатывающие заводы могут выбирать тот или иной тип переработки нефти, однако главная цель большинства этих типов состоит в устранении нежелательных сернистых соединений.
2. Очистка нефтепродуктов может быть выполнена либо на промежуточной стадии нефтепереработки, либо непосредственно перед отправлением конечного продукта на хранение.
3. Крекинг – процесс переработки тяжёлых нефтяных фракций с целью получения более ценных продуктов, таких как бензин, дизельное топливо и газойль.
4. Использование катализатора позволяет увеличить выход более качественных продуктов в гораздо менее жестких условиях, чем при использовании термического крекинга.
5. В качестве катализаторов используются, как правило, твердые вещества (цеолиты, алюмосиликаты, бентонитовые глины, фуллерова земля, бокситы и др.).
6. Водород, важный промежуточный продукт, выделяется из нефтяной фракции для повторной переработки и использования в других процессах.
7. Изомеризация имеет сходство с риформингом, поскольку здесь также присутствует перегруппировка молекул углево-дорода. Однако, в отличие от риформинга, изомеризация на-правлена лишь на преобразование парафинов в изопарафины.
8. Полимеризация может протекать термически или в присут-ствии катализатора при более низких температурах.
9. Алкилирование подразумевает объединение изкомолекуляр-ных олефинов с изобутеном в присутствии катализатора (серной или фтористоводородной кислоты).
10. Октановое число алкилата зависит, главным образом, от используемых олефинов и технологических условий.
Text 7 Natural Gas Processing
Figure 6
A
lthough
the processing of natural gas is in many respects less complicated
than the processing and refining of crude oil, it is equally as
necessary before its use by end users.
The natural gas used by consumers is composed almost entirely of methane. However, natural gas found at the wellhead, although still composed primarily of methane, is by no means pure. Raw natural gas comes from three types of wells: oil wells, gas wells, and condensate wells. Natural gas that comes from oil wells is typically termed 'associated gas'. This gas can exist separate from oil in the formation (free gas), or dissolved in the crude oil (dissolved gas). Natural gas from gas and condensate wells, in which there is little or no crude oil, is termed 'nonassociated gas'. Gas wells typically produce raw natural gas by itself, while condensate wells produce free natural gas along with a semi-liquid hydrocarbon condensate. Whatever the source of the natural gas, once separated from crude oil (if present) it commonly exists in mixtures with other hydrocarbons; principally ethane, propane, butane, and pentanes. In addition, raw natural gas contains water vapor, hydrogen sulfide (H2S), carbon dioxide, helium, nitrogen, and other compounds.
Natural gas processing consists of separating all of the various hydrocarbons and fluids from the pure natural gas, to produce what is known as 'pipeline quality' dry natural gas.
While the ethane, propane, butane, and pentanes must be removed from natural gas, this does not mean that they are all 'waste products'.
In fact, associated hydrocarbons, known as 'natural gas liquids' (NGLs) can be very valuable by-products of natural gas processing. NGLs include ethane, propane, butane, isobutane, and natural gasoline. These NGLs are sold separately and have a variety of different uses; including enhancing oil recovery in oil wells, providing raw materials for oil refineries or petrochemical plants, and as sources of energy.
While some of the needed processing can be accomplished at or near the wellhead (field processing), the complete processing of natural gas takes place at a processing plant, usually located in a natural gas producing region. The extracted natural gas is transported to these processing plants through a network of gathering pipelines, which are small-diameter, low-pressure pipes.
In addition to processing done at the wellhead and at centralized processing plants, some final processing is also sometimes accomplished at 'straddle extraction plants'. These plants are located on major pipeline systems. Although the natural gas that arrives at these straddle extraction plants is already of pipeline quality, in certain instances there still exist small quantities of NGLs, which are extracted at the straddle plants.
The actual practice of processing natural gas to pipeline dry gas quality levels can be quite complex, but usually involves four main processes to remove the various impurities:
Oil and Condensate Removal
Water Removal
Separation of Natural Gas Liquids
Sulfur and Carbon Dioxide Removal
In addition to the four processes above, heaters and scrubbers are installed, usually at or near the wellhead. The scrubbers serve primarily to remove sand and other large-particle impurities. The heaters ensure that the temperature of the gas does not drop too low. With natural gas that contains even low quantities of water, natural gas hydrates have a tendency to form when temperatures drop. These hydrates are solid or semi-solid compounds, resembling ice like crystals. Should these hydrates accumulate, they can impede the passage of natural gas through valves and gathering systems. To reduce the occurrence of hydrates, small natural gas-fired heating units are typically installed along the gathering pipe wherever it is likely that hydrates may form.
I. Choose the best answer according to the text.
1. The processing of natural gas is …..
a. as complicated as the processing and refining of crude oil
b. less complicated than the processing and refining of crude oil
c. less necessary than the processing and refining of crude oil
d. more necessary than the processing and refining of crude oil
2. The natural gas used by consumers is composed almost entirely of …..
a. ethane
b. propane
c. butane
d. methane
3. The gas that can exist separate from oil in the formation is termed ……
a. free gas
b. associated gas
c. dissolved gas
d. nonassociated gas
4. What do gas wells typically produce?
a. free natural gas along with a semi-liquid hydrocarbon condensate
b. crude oil
c. raw natural gas
d. 'pipeline quality' dry natural gas
5. What can’t be called 'waste products'?
a. sulfur and carbon dioxide
b. hydrates
c. large-particle impurities
d. 'natural gas liquids' (NGLs)
II. Find the English equivalents for the following Russian words and word combinations.
сложный; потребитель; полностью; устье скважины; совсем не; газ из добывающей скважины, попутный газ; газ, добываемый без нефти, непопутный газ; углеводородный конденсат, водяной пар, серoводород, углекислый газ, сухой природный газ, газоконденсатные жидкости.
III. Translate the following sentences into English.
1. Природный газ в том виде, в каком он доходит до потребителя, состоит преимущественно из метана.
2. Газ может находиться в залежи отдельно от нефти (свободный газ) или быть растворённым в нефти.
3. Добытый природный газ транспортируется на газоперерабатывающие заводы по межпромысловым трубопроводам.
4. Главная задача скрубберов – очистка от песка и других крупнозернистых примесей.
5. При скоплении гидратов последние могут препятствовать прохождению природного газа по газосборной трубопроводной системе.
UNIT 2
OIL AND NATURAL GAS
TRANSPORTATION AND STORAGE
Text 1