UNIT 8 WHAT IS NATURAL GAS?

8.1. Remember the meaning of the following words and word combinations:

combustible – горючий

fossil fuels – ископаемые виды топлива

to emit = to give off - выделять, испускать

harmful byproducts - вредные побочные продукты

primarily – в основном, главным образом

chart - таблица

composition - состав

carbon dioxide - углекислый газ

hydrogen sulfide - сероводород

trace - след

to deliver - доставлять

commonly – обычно

associated with - (зд.) сопровождающие, попутные

to remove - удалять

reservoir - коллектор

deposit - месторождение

to search for - искать

once - как только

to refine - очищать

impurities - примеси

compound - соединение

to exist - существовать

to measure - измерять

in a number of different ways – по-разному, различными способами

volume - объем

cubic feet - кубические футы

British thermal unit (Btu) - британская тепловая единица

pound - фунт (0,453 кг)

gas utility - газовая коммунальная служба

billing - выписка счета

8.2. Before reading the text check the pronunciation of the following words:

Carbon, hydrogen, hydrocarbons, sulfur, oxygen, nitrogen, carbon dioxide,

hydrogen sulfide, methane, ethane, propane, butane, argon, neon, helium, xenon

8.3. Read and translate the text using a dictionary.

What is Natural Gas?

Natural gas, in itself, might be considered a very uninteresting gas - it is colorless, shapeless, and odorless in its pure form. Quite uninteresting - except that natural gas is combustible, and when burned it gives off a great deal of energy. Unlike other fossil fuels, however, natural gas is clean burning and emits lower levels of potentially harmful byproducts into the air. We require energy constantly, to heat our homes, cook our food, and generate our electricity. It is this need for energy that has elevated natural gas to such a level of importance in our society, and in our lives.

Natural gas is a combustible mixture of hydrocarbon gases. While natural gas is formed primarily of methane, it can also include ethane, propane, butane and pentane. The composition of natural gas can vary widely, but below is a chart outlining the typical makeup of natural gas before it is refined.

Typical composition of natural gas

Methane (CH4) - 70-90%

Ethane (C2H6) - 0-20%

Propane (C3H8) - 0 - 5%

Butane (C4H10) - 0 - 5%

Carbon dioxide (CO2) - 0 - 8%

Oxygen (O2) - 0-0.2%

Nitrogen (N2) - 0 - 5%

Hydrogen sulfide (H2S) - 0 - 5%

Rare gases Ar, He, Ne, Xe trace

In its purest form, such as the natural gas that is delivered to your home, it is almost pure methane. Methane is a molecule made up of one carbon atom and four hydrogen atoms, and is referred to as CH4.

Ethane, propane, and the other hydrocarbons commonly associated with natural gas have slightly different chemical formulas, which can be seen here.

Natural gas is considered ‘dry’ when it is almost pure methane, having had most of the other commonly associated hydrocarbons removed. When other hydrocarbons are present, the natural gas is 'wet'.

Natural gas has many uses, residentially, commercially, and industrially. Found in reservoirs underneath the earth, natural gas is commonly associated with oil deposits. Production companies search for evidence of these reservoirs by using sophisticated technology that helps to find the location of the natural gas, and drill wells in the earth where it is likely to be found. Once brought from underground, the natural gas is refined to remove impurities like water, other gases, sand, and other compounds. Some hydrocarbons are removed and sold separately, including propane and butane. Other impurities are also removed, like hydrogen sulfide (the refining of which can produce sulfur, which is then also sold separately). After refining, the clean natural gas is transmitted through a network of pipelines, thousands of miles of which exist in the United States alone. From these pipelines, natural gas is delivered to its point of use.

Natural gas can he measured in a number of different ways. As a gas, it can be measured by the volume it takes up at normal temperatures and pressures, commonly expressed in cubic feet. Production and distribution companies commonly measure natural gas in thousands of cubic feet (Mcf), millions of cubic feet (MMcf), or trillions of cubic feet (Tcf). While measuring by volume is useful, natural gas can also be measured as a source of energy. Like other forms of energy, natural gas is commonly measured and expressed in British thermal units (Btu). One Btu is the amount of natural gas that will produce enough energy to heat one pound of water by one degree at normal pressure. To give an idea, one cubic foot of natural gas contains about 1,027 Btus. When natural gas is delivered to a residence, it is measured by the gas utility in 'therms' for billing purposes. A therm is equivalent to 100,000 Btu's, or just over 97 cubic feet, of natural gas.

8.4. Answer the questions on the text:

1) In what way is natural gas an uninteresting gas? 2) How does natural gas differ from other fossil fuels? 3) Where do we use it? 4) What is natural gas? 5) What is the composition of the typical natural gas? 6) What is the difference between the ‘dry’ and ‘wet’ natural gas? 7) Why is natural gas refined? 8) What happens to natural gas after refining? 9) What happens to impurities like propane, butane and sulfur? 10) How do production and distribution companies measure the volume of natural gas? 11) How is natural gas measured as a source of energy? 12) What is one Btu? 13) How does the gas utility measure natural gas?

8.5. Give English equivalents to the following word-combinations from the text:

бесцветный, бесформенный и без запаха; в чистом виде, обычный

состав (2), редкие газы, называться, считаться ‘сухим’, почти чистый метан,

признаки (наличия) коллектора, сложная технология, удалять примеси, отдельно, после очистки, перекачивать по сети трубопроводов, доставлять до места использования; компании, занимающиеся добычей и распределением, источник энергии, нагреть один фунт воды на один градус

8.6. Match the words in list A with their equivalents in list B and translate them:

List A

1) combustible 2) to give off 3) makeup 4) commonly 5) to transmit

6) a great deal of 7) to elevate 8) to search for 9) to refine 10) odorless

List B

a) usually b) much/many c) to remove impurities d) inflammable e) to raise

f) without smell g) to emit h) to move i) composition j) to look for

8.7. Choose the only correct variant to fill in the gaps:

1) Natural gas is ………………….. in its pure form.

a) not combustible b) separate c) without odor d) useless

2) The main component of natural gas is ……………..

a) propane b) methane c) butane d) ethane

3) Methane is a molecule made up of ……. carbon atom and ……. hydrogen

atoms.

a) one, six b) two, six c) four, ten d) one, four

4) When natural gas consists of almost pure methane it is called …………….

a) ‘wet’ b) ‘clean’ c) ‘dirty’ d) ‘dry’

5) Natural gas is produced from …………… under the earth.

a) reservoirs b) impurities c) refineries d) pipelines

6) Water, other gases, sand and other compounds that are removed from natural

gas are called …………..

a) reservoirs b) impurities c) mixtures d) fluids

7) The measurement of natural gas by the volume is expressed in …………….

a) liters b) thermal units c) cubic feet d) tons

8) The measurement of natural gas as a form of energy is expressed in ………...

a) British thermal units b) tons c) cubic feet d) liters

8.8. Give the summary of the text about natural gas using the following word

combinations:

in its pure form, combustible mixture of hydrocarbon gases, typical composition, ‘wet’, ‘dry’, many uses, to remove impurities, to transmit through pipelines, to measure by the volume, in cubic feet, be measured as a source of energy, British thermal units, one Btu

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