Cryogenic storage

Tanks with contents at lower than atmospheric temperature may require insulation to minimize heat absorption. The insulation must have a vapor barrier at the outside to prevent condensation of atmospheric moisture from reducing its effectiveness. An insulation not damaged by moisture is preferable. The insulation techniques presently used for refrigerated systems can be apphed (see subsection Fow-Temperature and Cryogenic Storage ). 

Underground chambers are also constructed in frozen earth (see subsection Xow-Temperature and Cryogenic Storage ). Underground tunnel or tank storage is often the most practical way of storing hazardous or radioactive materials. A cover of 30 m (100 ft) of rock or dense earth can exert a pressure of about 690 kPa (100 Ibf in"). 

Prior to entry into large tanks containing inert medium, ensure that pipes to the tank from cryogen storage are blanked off or positively closed off purge with air and check oxygen levels. 

At Qatar, the liquid came out with such force that it spilled over the dike wall. Conventional dike walls also have the disadvantage that a large area of liquid is exposed to the atmosphere if a leak occurs. For these reasons it is now usual to surround cryogenic storage tanks with a concrete wall, about 1 m from the tank and the full height of the tank. If the tank is not made from crack-resistant material, then the concrete wall should be designed to withstand the effects of a sudden release of liquid. 

N. J. Cupurus, Cryogenic Storage Facilities for LNG and NGL, Proceedings of the Tenth World Petroleum Congress, Heyden, London, 1979, p. 119 (Panel Discussion 17, Paper 3). 

N. J. Cupurus, Developments in Cryogenic Storage Tanks, Paper presented at 6th International Conference on Liquefied Natural Gas, Kyoto, Japan, 1980. 

Monitoring the purge gas from cold boxes and double walled insulated cryogenic storage tanks. 

The cost of salt dome construction is cheaper than mined-cavern storage, which in turn is a lot cheaper, per pound of ethylene, than cryogenic storage and pressure storage. 

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