An LNG port or LNG terminal is a facility that allows the regasification of the LNG (LIQUEFIE NATURAL GAS), transported by the seaway from the production zones. How does this installation work? What are the LNG terminals in Africa? And what are the safety measures that must be taken into account in the transport of LNG per LNG tanker?
A LNG terminal: How does it work?
LNG terminal has four functions; the first is the receipt of ships and the unloading of cargo. After the LNG ship is docked at the unloading dock at the terminal level, an articulated arm with a pipeline (which allows unloading of the cargo and the carriage of LNG to the reservoirs) plugs into the isothermal vats of the LNG tanker and route it to the reservoir. This operation lasts less than 12 hours. The second function is the storage of LNG, which is stored in cryogenic reservoirs capable of withstanding a temperature of -160 ° C to keep the LNG liquid. The outer envelope of the tanks is made of prestressed reinforced concrete or steel. Their isolation helps to limit evaporations. But despite the quality of the insulation, there is low heat inputs in the equipment containing LNG, and because of these external heats, a small part of the LNG are converted into evaporation gas. This part is recovered and reincorporated through evaporation gas compressors and condensers.
The third stage is the regasification of LNG; it is put under pressure and heated with heat exchangers to transform it from a liquefied to a gas. Indeed, each tank is equipped with submerged pumps that ensure the transfer of LNG to high pressure pumps. The LNG pressurized at approximately 80 times the atmospheric pressure is vaporized in the regasifers.
The fourth stage is the emission on the national transport network but before this phase the LNG underwent several treatments. Natural gas that is odorless is artificially odorized. This is a safety measure to detect gas leaks. LNG can also be transported by tanker trucks for non-connected industrialists. In this case the LNG is transferred from the terminal reservoir to the discharge station and then connected to the LNG circuit of the terminal. LNG transits through flexible pipes to the tank of the truck. The latter is weighed upon arrival and exit of the terminal on a rocking bridge to count the loaded LNG.
LNG terminals in Africa
There are four African countries that have LNG terminals. In Algeria there are GL1K Sonatrach in Skikda, GL1Z, GL2Z and GL3Z Sonatrach in Bethouia, GL4Z ex CAMEL in Arzew. In Egypt there are segas Damietta LNG and ELNG IDCO LNG. In Angola there is a terminal at Soyo. In Nigeria there is Nigeria LNG in Bonny.
Security at the LNG terminal
To reduce the risk of LNG transport by tankers, security measures are required: temperature controls, pressure, oxygen absence check, vat inspection etc. Nevertheless, there is a risk of fire. If the LNG escapes from a hull and meets the spark, a fire may occur, although the risk of explosion is nonexistent. For this reason, tankers have a double hull, reducing the risk of LNG escaping.
The LNG tanks are also designed to limit the risk of accidents by including a gas nitrogen barrier, which avoids any natural gas (LNG) react with oxygen from the air. Many countries include specific safety regulations regarding the access of tankers to channel. When a tanker is engaged in a channel, this last access is forbidden to other opposite vessels (to avoid crossing in the channel between the tanker and the other vessel).
LNG terminals are facilities available in all natural gas-consuming countries. They are constructed for the purpose of receiving liquefied natural gas (LNG) transported by ship, for regasification and injecting it into the natural gas transmission system as the demand is made.