Liquefied natural gas

LiquefiednaturalgasFromWikipedia,thefreeencyclopediaJumpto:navigation,searchNottobeconfusedwithNaturalgasprocessingorLiquefiedpetroleumgas.Thisarticleneedsadditionalcitationsforverification.Pleasehelpimprovethisarticlebyaddingreliablereferences.Unsourcedmaterialmaybechallengedandremoved.(February2008)LiquefiednaturalgasorLNGisnaturalgas(predominantlymethane,CH4)thathasbeenconvertedtemporarilytoliquidformforeaseofstorageortransport.Liquefiednaturalgastakesupabout1/600ththevolumeofnaturalgasinthegaseousstate.Itisodorless,colorless,non-toxicandnon-corrosive.Hazardsincludeflammability,freezingandasphyxia.AtypicalLNGprocess.Thegasisfirstextractedandtransportedtoaprocessingplantwhereitispurifiedbyremovinganycondensatessuchaswater,oil,mud,aswellasothergaseslikeCO2andH2Sandsometimessolidsasmercury.Thegasisthencooleddowninstagesuntilitisliquefied.LNGisfinallystoredinstoragetanksandcanbeloadedandshipped.Theliqueficationprocessinvolvesremovalofcertaincomponents,suchasdust,acidgases,helium,water,andheavyhydrocarbons,whichcouldcausedifficultydownstream.Thenaturalgasisthencondensedintoaliquidatclosetoatmosphericpressure(maximumtransportpressuresetataround25kPa/3.6psi)bycoolingittoapproximately−162°C(−260°F).Thereductioninvolumemakesitmuchmorecostefficienttotransportoverlongdistanceswherepipelinesdonotexist.Wheremovingnaturalgasbypipelinesisnotpossibleoreconomical,itcanbetransportedbyspeciallydesignedcryogenicseavessels(LNGcarriers)orcryogenicroadtankers.TheenergydensityofLNGis60%ofthatofdieselfuel.[1]Contents[hide]1Basicfacts2Production3Imports4Commercialaspects5Trade6LNGpricingo6.1Oilparityo6.2S-Curve6.2.1JCCandICP6.2.2Brentandotherenergycarriers7Pricereview8Cargodiversion9QualityofLNG10CostofLNGplantso10.1SmallScaleLiquefactionPlants11Liquefactiontechnology12Environmentalconcerns13Safetyandaccidents14Storage15Transportationo15.1Terminals16Refrigeration17Seealso18References19Externallinks20Othersources[edit]BasicfactsLNGisprincipallyusedfortransportingnaturalgastomarkets,whereitisregasifiedanddistributedaspipelinenaturalgas.Itcanbeusedinnaturalgasvehicles,althoughitismorecommontodesignvehiclestousecompressednaturalgas.Itsrelativelyhighcostofproductionandtheneedtostoreitinexpensivecryogenictankshavepreventeditswidespreaduseincommercialapplications.ThedensityofLNGisroughly0.41kg/Lto0.5kg/L,dependingontemperature,pressureandcomposition,comparedtowaterat1.0kg/L.Theheatvaluedependsonthesourceofgasthatisusedandtheprocessthatisusedtoliquefythegas.ThehigherheatingvalueofLNGisestimatedtobe24MJ/L.ThelowerheatingvalueofLNGis21MJ/Lor635BTU/ft3.ForthepurposeofcomparisonofdifferentfuelstheheatingvalueisalsoknownastheenergydensityexpressedinMJ/LorthegasolinegallonequivalentexpressedinBTU/ft3.TheenergydensityofLNGis2.4timesgreaterthanthatofCNGwhichmakesiteconomicaltotransportnaturalgasintheformofLNGbyship.TheenergydensityofLNGiscomparabletopropaneandethanolbutisonly60%thatofdieseland70%thatofgasoline[2].[edit]ProductionThenaturalgasfedintotheLNGplantwillbetreatedtoremovewater,hydrogensulfide,carbondioxideandothercomponentsthatwillfreeze(e.g.,benzene)underthelowtemperaturesneededforstorageorbedestructivetotheliquefactionfacility.LNGtypicallycontainsmorethan90%methane.Italsocontainssmallamountsofethane,propane,butaneandsomeheavieralkanes.Thepurificationprocesscanbedesignedtogivealmost100%methane.OneoftheveryrarerisksofLNGisrapidphasetransition(RPT),whichoccurswhencoldLNGcomesintocontactwithwater[3].ThemostimportantinfrastructureneededforLNGproductionandtransportationisanLNGplantconsistingofoneormoreLNGtrains,eachofwhichisanindependentunitforgasliquefaction.ThelargestLNGtrainnowinoperationisinQatar.UntilrecentlyitwastheTrain4ofAtlanticLNGinTrinidadandTobagowithaproductioncapacityof5.2millionmetrictonperannum(mmtpa),[4]followedbytheSEGASLNGplantinEgyptwithacapacityof5mmtpa.TheQatargasIIplanthasaproductioncapacityof7.8mmtpaforeachofitstwotrains.LNGisloadedontoshipsanddeliveredtoaregasificationterminal,wheretheLNGisreheatedandturnedintogas.Regasificationterminalsareusuallyconnectedtoastorageandpipelinedistributionnetworktodistributenaturalgastolocaldistributioncompanies(LDCs)orindependentpowerplants(IPPs).InformationforthefollowingtableisderivedinpartfrompublicationbytheUSEnergyInformationAdministration.[5]PlantNameLocationCountryStartupDateCapacity(mmtpa)CorporationQatargasIIRasLaffanQatar20097.8ArzewGL4ZAlgeria19640.9ArzewGL1ZAlgeria1978upgradedArzewGL1ZupgradeAlgeria19977.9SkikdaGL1KAlgeria1972upgradedSkikdaGL1KUgradeIAlgeria1981upgradedSkikdaGL1KUgradeIIAlgeria19996.0Lumut1Brunei19727.2BontangA-BIndonesia1977expandedBontangA-DIndonesia1986expandedBontangA-EIndonesia1989expandedBontangA-FIndonesia1993expandedBontangA-GIndonesia1998expandedBontangA-HIndonesia199922.6PointFortinTrinidadandTobago1999expandedAtlanticLNGPointFortinexpansionTrinidadandTobago20039.9AtlanticLNGDamiettaEgypt20045.5SegasLNGIdkuEgypt20057.2BintuluMLNG1Malaysia19837.6BintuluMLNG2Malaysia19947.8BintuluMLNG3Malaysia20033.4BonnyIslandNigeria1999exp