What is LNG?

Gorgon Project
What is LNG?
What is Natural Gas?
What is LNG?
Lique? ed
natural gas
Natural gas comes from reservoirs beneath the earth’s
Lique? ed natural gas (LNG) is natural gas that has
surface. Sometimes it occurs naturally and is produced
been cooled to the point that it condenses to a liquid,
(LNG) is natural
by itself (non-associated gas), sometimes it comes to the
which occurs at a temperature of approximately -256°F
surface with crude oil (associated gas), and sometimes
(-161°C) and at atmospheric pressure. Liquefaction
gas that has
it is produced constantly such as in land? ll gas. Natural
reduces the volume by approximately 600 times, making
been cooled to
gas is a fossil fuel, meaning that it is derived from
it more economical to transport between continents
organic material deposited and buried in the earth
in specially designed ocean vessels. LNG technology
the point that it
millions of years ago. Other fossil fuels are coal and
makes natural gas available throughout the world.
crude oil. Together crude oil and gas constitute a type
condenses to a
of fossil fuel known as “hydrocarbons” because the
To make LNG available for use, energy companies must
liquid.
molecules in these fuels are combinations of hydrogen
invest in a number of different operations that are
and carbon atoms. The main component of natural gas is
highly linked and dependent upon one another. The
methane. Methane is composed of one carbon and four
major stages of the LNG value chain, excluding pipeline
hydrogen atoms (CH ). When natural gas is produced
operations between the stages, consist of the following.
4
from the earth, it includes many other molecules, like
• Exploration to ? nd natural gas in the earth’s crust and
ethane (used for manufacturing), propane (which we
production of the gas for delivery to gas users. Most
commonly use for bbq’s) and butane (used in lighters).
of the time natural gas is discovered during the search
for oil.
We can ? nd natural gas around the world by exploring
for it in the earth’s crust and then drilling wells to
• Liquefaction to convert natural gas into a liquid state
produce it. Natural gas can be transported over long
so that it can be transported in ships.
distances in pipelines or as LNG transported in ships
across oceans. Natural gas can be stored until needed
• Shipping the LNG in special purpose vessels.
in underground caverns and reservoirs or as LNG in
• Storage and Regasi? cation, to convert the LNG
atmospheric tanks.F
stored in specially made storage tanks, from the
lique? ed phase to the gaseous phase, ready to be
moved to the ? nal destination through the natural gas
pipeline system
Operated by Chevron Australia
in joint venture with

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The LNG is
Composition of Natural Gas and LNG
LNG is a cryogenic liquid. The term “cryogenic” means
low temperature, generally below -100°F. LNG is clear
stored in double-
Natural gas is composed primarily of methane,
liquid, with a density of about 45 percent the density
but may also contain ethane, propane and heavier
of water.
walled tanks at
hydrocarbons. Small quantities of nitrogen, oxygen,
atmospheric
carbon dioxide, sulfur compounds, and water may also
The LNG is stored in double-walled tanks at
be found in natural gas. The ? gure above provides
atmospheric pressure. The storage tank is really a tank
pressure. The
a typical natural gas composition. The liquefaction
within a tank that is ? lled with insulation. The inner
process requires the removal of some of the non-
tank, in contact with the LNG, is made of materials
storage tank
methane components such as water and carbon dioxide
suitable for cryogenic service and structural loading
is really a tank
from the produced natural gas to prevent them from
of LNG. These materials include 9 percent nickel steel,
forming solids when the gas is cooled to about LNG
aluminum and pre-stressed concrete. The outer tank
within a tank
temperature (-256°F). As a result, LNG is typically
is generally made of carbon steel or pre-stressed
made up mostly of methane.
concrete.
that is ? lled with
insulation.
LNG is odorless, colorless, non-corrosive, and non-
toxic. However, as with any gaseous material besides
air and oxygen, the natural gas vaporized from LNG can
cause asphyxiation in an unventilated con? nement.
LNG Liquefaction
Feed gas to the liquefaction plant comes from
the production ? eld. The contaminants found in
produced natural gas are removed to avoid freezing
and damaging equipment when the gas is cooled
to LNG temperature (-256°F) and to meet pipeline
speci? cations at the delivery point. The liquefaction
process can be designed to purify the LNG to almost
100 percent methane.
The liquefaction process entails cooling the clean
feed gas by using refrigerants. The liquefaction plant
may consist of several parallel units (“trains”). The
natural gas is lique? ed for shipping at a temperature of
approximately -256°F. By liquefying the gas, its volume
is reduced by a factor of 600, which means that LNG
at -256°F uses 1/600th of the space required for a
comparable amount of gas at room temperature and
atmospheric pressure.
For more information about the Gorgon Project contact
Email: gorgon.info@chevron.com
www.gorgon.com.au

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