Natural Gas Liquefaction

Natural gas liquefies when cooled to around -160°C, a temperature that varies slightly according to the properties of the gas. The gas is transported by gas pipelinePipeline used to transport gas over a long distance, either on land or on the seabed. from the production site to a nearby liquefactionConversion of a gas to a liquid. In industrial applications, gas is liquefied by cooling and/or pressurization... plant, where it undergoes several processes :¹

• Processing: The extracted gas is purified to remove substances such as water and mercury in order to comply with natural gas marketing specifications and prepare for the liquefaction step. Certain substances can corrode or damage the equipment and cause deposits to form during liquefaction at very low temperature.

• Cooling: After the initial cooling stage, the gas is distilled to separate out preservation (hydrocarbons)The final phase in petroleum system formation, after a deposit has accumulated... such as propane and butane, which are liquefied petroleum gases (LPGAutogas refers to liquefied petroleum gas, or LPG (see definition), used as a fuel for cars... ) that can be used as automotive fuelFuel is any solid, liquid or gaseous substance or material that can be combined with an oxidant... . The gas is then pumped through several heatIn the field of statistical thermodynamics today, heat refers to the transfer of the thermal agitation of the particles making up matter... exchangers, where it cools down in stages before liquefying at -160°C. Chilling takes place in a closed loop using one or several hydrocarbonOrganic compound consisting of carbon and hydrogen. Hydrocarbons are the principal constituents of crude oil, natural gas and petroleum products. fluids as a coolant. The facility is called a liquefaction trainA series of heat exchangers that gradually reduce the temperature of natural gas to -160°C... . A liquefaction plant can comprise several trains.

• Storage: At ambient conditions, liquefied natural gas (lng)LNG is composed almost entirely of methane. Liquefying the gas reduces its initial volume by a factor of around 600... takes up roughly 600 times less space than in its gaseous state, while retaining the same properties: it is colorless, non-toxic and nonflammable in the absence of oxygen. LNG is stored in large tanks at atmospheric pressure and then loaded onto an LNG carrier (See Close-Up: "Transportation by LNG Carrier and Regasification").  

Liquefaction plants are located as near as possible to production sites. Natural gas produced from offshoreRefers to sea-based oil exploration and production operations, as in "offshore license" or "offshore drilling". reservoirs is often piped back to land, but research has recently been focused on developing floating LNG plants. A number of projects are currently being examined.²  For oil exporting countries with offshore deposits, floating LNG solutions open up new prospects for making challenging offshore deposits commercially viable.

Sources: 

 (1) Total

(2)  Shell