FLAT BOTTOM OR VACUUM INSULATED TANKS - GasEner

FEROXFLAT BOTTOM ORVACUUM INSULATEDTANKS?VACLAV CHRZ, JIRI KRIVAN,PETR ZARUBA, JIRI ZEMANChart-Ferox, a.s.vaclav.chrz@chart-ferox.com

Dilemma ofLiquefied Cryogenic GasStorage Projects There is no doubt, that for storage ofquantities less than 250 m3, vacuuminsulated tanks are the best option There is no doubt, that for storage ofquantities larger than 50 000 m3 flatbottom tanks are the best option What about the intermediate region?

Design of a Flat Bottom TankOuter vesselInner vesselPerlite insulation18500Sand layer147801400016000800Foamglass bricks950Concrete platformApprox. 3000Concrete collumnsContainmentConcrete fundamentAnchoring

Flat bottom tanks during construction

1800 m32200 m3

Vacuum insulated tank designinner vesselouter vesselperlite-vacuuminner suportsouter supports

Vertical tank foundation with acontainment (in process)

Erection ofa verticalVacuumInsulatedtank(212 m3 LNG,Statoil,Norway

Large Vacuum Insulated tanksHT500 (LNG, Norway, 3 pieces in 2003)volume: 500 000 litersweight: 130 000 kgø5m36 m

Naturgas Vest, Sunndalsora, NorwayStorage capacity 1500 m3 of LNG, Vaporization 3000 Nm3/h

Comparison of Flat Bottom andVacuum Insulated tanks(Qualitative) Project lay-outManufacturing and ConstructionProcess designPressure dynamicsRisk with catastrophic accidents

Project lay-outFlat bottomNumber of unitsContainment volume neededGround area neededDesign of concrete foundationsand containmentoneVacuum insulatedmorethe whole single tank volumestorage volumevertical:smallmarginally largerhorizontal: muchlargerexpensivelower cost

Manufacturing andConstructionFlat bottomVacuum insulatedMethod of manufacturingon site with shop shop manufacturedpreparationLead time of shop workLead time of on site constructionPossibility of sequential building-upand commissioning (two or threestages, e.g.)Easy to move in case of change ofmarket environmentseveral weeksseveral monthsnoseveral weeksseveral daysyesnoyes

Process designFlat bottomVacuum insulatedTypical max. pressure (bar)0,058Need of discharge pumpyesnoNet daily evaporation rate due toheat leak0.1 to 0.2%/day 0.06 to 0.08%/dayOperators’ access for inspection anddifficulteasymaintenance(all on the roof) (ground level)

Pressure dynamicsFlat bottomNeed of pressure control according to atmosphericpressureDanger of roll over(spontaneous shrug down of stratified liquidwith risky vapor generation and pressure growth)Maximum boil-off generation at roll-overNeed of boil-off compressors (sized to maximum)Consequent need of temperatureand concentration profile continuous controlVacuum insulatedyesnoyes0.04 to0.24%/houryesnoneyesnono

Risk with catastrophicaccidentsFlat bottomResistance to earthquake –measures neededCatastrophic events –war, terrorism, airplane fall,industrial catastrophyPossibility of partial operationafter a case of failure or accidentVacuuminsulateddifficulteasyrisk of totaldamagesingle orseveraltanksnoyes

Economic ComparisonPrice per m 3 [non-currency]Storage technology price (example)100FB?Multiple VI500 m3VI101000*VI or FB10000Volume [m3]FB only100000

Conclusion Progress in manufacturing of largeVacuum Insulated tanks makes possibledesign of sizes 500 m3 and larger. Multiple use of these tanks is a realisticalternative to Flat Bottom tanks. This alternative should be always takeninto account when projecting storageswith total volume up to 15 000 m3.

Vacuum Insulated tanks makes possible design of sizes 500 m3 and larger. Multiple use of these tanks is a realistic alternative to Flat Bottom tanks. This alternative should be always taken into account when projecting storages with total volume up to 15 000 m3.