The LNG Chain

Natural gas is located beneath the earth’s surface from which it is extracted through a drilling process. Qatar, in the Arabian Gulf, north-east of the coast, hosts the major gas field in the world not associated with oil, the North Field.
Discovered in the early 70’s, its recoverable reserves are estimated around 25,000 billion cubic meters (900,000 billion cubic feet), equal to about 10% of all the world’s known reserves. This makes Qatar the number three country in the world for gas reserves, after Russia and Iran. From the North Field, gas is transported – with its own pressure and uncompressed – to the industrial town of Ras Laffan, where it is treated.

The liquefaction process makes it possible to transport large volumes of LNG to consumer countries.
The gas extracted from the North Field reaches – via pipeline – the industrial plants in the town of of Ras Laffan. Here it is treated to remove impurities and cooled off to –162°C to convert it to the liquid state.
The liquefaction plants work as enormous refrigeration installations and are organized in parallel processing units, called “trains,” each of which treats one portion of gas to be liquefied.
Natural gas is typically composed of over 90% of methane but also contains small quantities of other substances.
In the liquefaction trains, pure gas is first treated to remove water, propane, heavier hydrocarbons, nitrogen and other impurities that could cause malfunctions in the liquefaction plant or that could solidify at the low temperatures necessary for storage.
At the end of the liquefaction process, the original gas volume is reduced by about 600 times. LNG therefore occupies an area 600 times smaller than natural gas at ambient temperature and atmospheric pressure. At this point LNG may be placed in storage tanks before being loaded onto special tanker ships.

Liquefied natural gas travels at a constant temperature and at atmospheric pressure, on special tankers, designed and built in accordance with strict safety standards. The LNG industry has linked some of the largest deposits of gas in the world – often remote and hard to reach – to countries requiring new supply sources.

Regasification is a relatively simple process of heating LNG to the point at which it returns to its original gaseous state. The key element of this phase is the regasification terminal. When the LNG carriers reach terminal Adriatic LNG, the liquefied natural gas is unloaded and stored at the temperature of –162°C, at atmospheric pressure, in special tanks. It is then sent to the regasification plant where it is converted to gaseous state through a controlled heating process.
After the regasification process the gas is injected into the national network through the pipeline.