How does LNG work?

Doha, Tuesady, 2nd February 2016.  

An educational review by QGN as Qatar is the the world’s biggest producer of liquefied natural gas and it cut exports of the fuel for the first time since at least 2006 as Australia and the U.S. prepare to erode the Middle Eastern nation’s dominant position. The Qatari volumes dropped 2.1 percent from a year earlier in 2014 after at least eight years of gains. The nation’s share of global LNG imports shrank to 31.9 percent from a peak of 32.9 percent in 2013. The industry is waiting for the wave of new exports from the U.S. and from Australia, who will likely top the producers’ list by 2020. Qatar, whose North Field is part of the world’s biggest gas reservoir, dominates the market with output from its 14 LNG plants, known as trains. The nation has capacity to produce 77 million metric tons a year of the fuel, or 26 percent of the world’s total. That is being challenged by Australia and the U.S., which are building a total of 99 million tons of annual capacity.

How does LNG work?

Liquefied natural gas (LNG) is natural gas (predominantly methane, CH4) that has been converted to liquid form for ease of storage or transport. It takes up about 1/600th the volume of natural gas in the gaseous state.

What’s LNG? …LNG is natural gas that is cooled into liquid form at -160 degrees Centigrade, reducing it to one-six-hundredth of its original size. It is stored and transported in insulated tankers which minimize vaporization resulting from heat ingress. The LNG is transported by tankers to different destinations. On arrival, it is converted back into a gaseous form for delivery to users such as power stations, industries, commercial buildings and domestic. LNG is composed of a mixture of hydrocarbon gases that occur with petroleum deposits, principally methane together with varying quantities of ethane, propane, butane, and other gases, and is used as fuel and in the manufacture of organic compounds.” Liquefied natural gas or LNG is natural gas (predominantly methane, CH4) that has been converted temporarily to liquid form for ease of storage or transport. Liquefied natural gas takes up about 1/600th the volume of natural gas in the gaseous state. It is odorless, colorless, non-toxic and non-corrosive. Hazards include flammability, freezing and asphyxia.

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 The Energy Process – LNG Vaule Chain

A typical LNG process …The gas is first extracted and transported to a processing plant where it is purified by removing any condensates such as water, oil, mud, as well as other gases like CO2 and H2S and sometimes solids as mercury. The gas is then cooled down in stages until it is liquefied. LNG is finally stored in storage tanks and can be loaded and shipped. The liquefication process involves removal of certain components, such as dust, acid gases, helium, water, and heavy hydrocarbons, which could cause difficulty downstream. The natural gas is then condensed into a liquid at close to atmospheric pressure (maximum transport pressure set at around 25 kPa/3.6 psi) by cooling it to approximately −162 °C (−260 °F). The reduction in volume makes it much more cost efficient to transport over long distances where pipelines do not exist. Where moving natural gas by pipelines is not possible or economical, it can be transported by specially designed cryogenic sea vessels (LNG carriers) or cryogenic road tankers. The energy density of LNG is 60% of that of diesel fuel. A typical LNG process The gas is first extracted and transported to a processing plant where it is purified by removing any condensates such as water, oil, mud, as well as other gases like CO2 and H2S and sometimes solids as mercury. The gas is then cooled down in stages until it is liquefied. LNG is finally stored in storage tanks and can be loaded and shipped.

 LNG Transportation …An LNG carrier is a tank ship designed for transporting liquefied natural gas (LNG). As the LNG market grows rapidly, the fleet of LNG carriers continues to experience tremendous growth.

 LNG Storage …A liquefied natural gas storage tank or LNG storage tank is a specialized type of storage tank used for the storage of Liquefied Natural Gas. LNG storage tanks can be found in ground, above ground or in LNG carriers. The common characteristic of LNG Storage tanks is the ability to store LNG at the very low temperature of -162 °C (-260 °F). LNG storage tanks have double containers, where the inner contains LNG and the outer container contains insulation materials. The most common tank type is the full containment tank. Tanks are roughly 55 m (180 ft) high and 75 m (250 ft) in diameter (=250 000 m³). In LNG storage tanks if LNG vapours are not released, the pressure and temperature within the tank will continue to rise. LNG is a cryogen, and is kept in its liquid state at very low temperatures. The temperature within the tank will remain constant if the pressure is kept constant by allowing the boil off gas to escape from the tank. This is known as auto-refrigeration.

 LNG Regasification Terminal …LNG regasification terminals are the keys to unlocking markets. In regasification terminals, the ultimate destination of LNG carriers, the liquefied natural gas is returned to its initial, gaseous state, then fed into transmission and distribution networks.

 OnShore …Regasification terminal– Land facility for receiving, unloading, storing and re-gasifying LNG, usually including breakwaters, tanker berthing and other marine facilities.

OffShore …Regasification terminal – Offshore facility for receiving, unloading, storing and re-gasifying LNG.

The Benefits of LNG as Opposed to Gas Transported by Pipelines …The biggest advantage of having access to the LNG market and being able to import it, is the proof of the existence of alternative sources of LNG supply, which is necessary both for the safety of the total company supply so as to meet the needs of its clients, as well as for the correction of the Load Factor of its consumers-clients for whom the imported LNG is intended for. Furthermore, the supply and import of LNG also contributes to the overall security of gas supply of SE Europe, since the supply of LNG is not affected by geopolitical or other financially problems that may occasionally occur in transit countries from which the gas supply pipelines go through. In terms of price, changing conditions in the world natural gas market in the last 3 years have affirmed LNG as being a much more competitive commodity to pipeline gas, due to the collapse of prices on the world’s largest market, the U.S., brought on by the development of indigenous shale gas (nonconventional gas).

Sources: https://kindle.amazon.com/search/books?keywords=dr.+theodore+theodoropoulos&start=1

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