Underground operations are more advantageous to LNG storage.
Liquefied natural gas (LNG) contains mostly methane and represents a converted form of natural gas. This conversion facilitates the gases' easy transportation and storage. Being a flammable asphixiant, LNG causes suffocation when inhaled. It is also odorless and nearly impossible to detect its infiltration into the air. The benefits of underground storage include its cost-effectiveness, environmental friendliness and better assurances of safety and security. The Energy Economics Research at the Bureau of Economic Geology at the University of Texas released pertinent information concerning LNG's underground safety issues. In addition, the U.S. Department of Energy and the Federal Energy Regulatory Commission (FERC) outlined LNG storage safety regulations based on the Energy Policy Act and the Natural Gas Act of 2005.
Safety Zones
Subterranean LNG storage tanks must be sunk at a great depth and covered securely with concrete caps. This inconspicuous design allows LNG tanks to blend seamlessly into the environment. LNG also enforces mandatory separation distances so that public utilities and community residences are not negatively affected by gaseous releases into the atmosphere or underground water systems. These safety zones are required under regulations.
Containment
Underground LNG containers are multi-layered to keep enclosed the inside elements. Frozen rock, steel and concrete barriers assist in containing liquids and gases such as hydrocarbons. Also, an installed water drainage system has to be set up to prevent unwanted entrance into the storage tanks. Insulated walls on the inner and outer shells of tanks promote restraint of movement of substances within and without.
Monitoring
Monitoring and control systems including alarm systems, back-up safety and emergency shutdown systems help to identify leakages and limit LNG vapor. These safeguard systems kick in whenever equipment fails to function properly or in changed environmental conditions.
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