LNG VALUE CHAIN AND SHIPPING OF OIL
WHAT IS THE LNG VALUE CHAIN ? •
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The LNG value chain represents $7 to $14 billion dollars of investment , further minimization of the cost with long term contract It begins with natural gas extracted from underground reservoirs and is sent through a pipeline to a liquefaction facility. At the liquefaction facility, impurities are removed from the gas, and it is sent through three cooling processes until it reaches a final temperature of minus 260 degrees Fahrenheit. The chilled gas, now LNG, is then loaded onto specially designed tanker ships, which may last anywhere from four to thirty days, depending on the destination port.
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Once the ship arrives at a re-gasification terminal, the LNG is offloaded into large storage tanks, built with full-containment walls and systems to keep the LNG cold until it is turned back into a gaseous state. When the LNG has been warmed back to its natural state, the gas is moved into pipelines which will deliver the natural gas to consumers, power plants and industrial customers across the country. The largest component of the total cost of the LNG value chain is usually the liquefaction plant, while the production, shipping, and regasification components account for nearly equal portions of the remainder
LIQUEFACTION •
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Total capacity of 170MTPA is available , 91 MTPA is under construction and further 285 MTPA is planned During the process , impurities are removed and the gas is cooled up to ( -256 F ) , the process can be designed to get upto 100% methane
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By the process its volume is reduced to 1/600
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Stored in a two walled tank , separated by insulation.
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The material includes nickel , aluminum and pressed concrete.
LNG Liquiefaction Process
SHIPPING Its shipped in a double hulled tanker , designed and insulated to prevent accidents There are three types of cargo containment for LNG , Moss ( spherical design ) Membrane design Structural prismatic A carrier can transport upto 125000 – 138000 m3 of LNG , which would provide 2.6-2.8 Bcf of natural gas A typical carrier measure 900ft in length and 140 ft in width, 36ft in water draft costing $160 million •
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SHIPPING International trade in LNG centers on two geographic regions The Atlantic Basin, involving trade in Europe, northern and western Africa, and the U.S. Eastern and Gulf coasts. The Asia/Pacific Basin, involving trade in South Asia, India, Russia, and Alaska. The carriers are less polluting than other vessels since they burn natural gas along with fuel oil for propulsion •
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SHIPPING
STORAGE •
At final destinations, LNG may be used in various ways,
Used as a transportation fuel for truck and bus fleets
Used electric power generation stations, allowing use of the cryogenic properties
Back to natural form
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On arrival at the receiving terminal in its liquid state, LNG is pumped at atmospheric pressure first to a doublewalled storage tank US stands tall in storage facility , mainly because of their demand
TYPES OF STORAGE •
There are three different types of storage ,
Above ground – most
widely used
Below ground – entirely submerged in land ,
with a cap in the surface . Provides environmental safety In ground – partial
submergence
STORAGE TANK
CONCRETE
INSULATION INNER TANK ( 9% NICKELSTEEL ALLOY ) BLOCKS
STAINLESS STEEL FOAM GLASS HEATING DUCTS TO PREVENT GROUND FREEZING
SINGLE CONTAINMENT TANK
Conceptual Design of Storage Tanks:
UNDERGROUND LNG TANK
REGASIFICATION
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The previous picture represents the process of taking liquefied natural gas (LNG) off of the ship, moving it into cold storage tanks and then re-gasifying it back into natural gas to send to market. The gray lines represent natural gas, and the yellow lines represent LNG. Naturally, there is a small amount of LNG which vaporizes through contact with warmer air in the top of the ship containers and in the LNG storage tanks. This natural gas is siphoned out of the tanks and moved into the pipeline.
ENERGY BRIDGE REGASSIFICATION VESSEL Used in case of off shore plant , where the LNG is taken up by the vessel and regassified in it and sent through downstream pipeline
JETTY
LNG IN INDIA •
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Existing LNG terminals at Dahej , Kochi , Hazira ( Shell ) and Dabhol Two LNG terminals planned , one at a Ennore and another at Mangalore , with a provision to capacity to 5 MMTPA each.
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Southern Gas Grid - 85 MMSCMD
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Imports from Oman , Iran and Qatar
LNG - A SAFE FUEL •
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Safety in LNG industry employs four main elements which would ensure safety of both the workers and the communities surrounding the LNG facility Primary containment – usage of appropriate material and a well designed engineering storage system Secondary containment - incase of leaks , ability to contain it and isolate from public Safeguard system - ESD system Separation distance maintaining safe distances with storage area LNG trucks have to maintain safe distance from other vehicles Transportation of LNG carriers via separate route Physical and chemical properties
POSSIBLE HAZARDS •
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Explosion – an explosion occurs when a substance rapidly changes from its chemical state or uncontrollable released from pressurized container , since LNG is stored at atmospheric pressure it will not create immediate explosion Vapour cloud – LNG forms a vapour cloud when released and it may ignite if it encounters an ignition source Freezing liquid Rapid phase transition – An RPT can occur , if there is a mix of water and LNG. RPT range from small pops to a blast
