Cooldown of a Large Tank

For methane at 300 K, S is about 430 m/s hence v is less than the order of 0.4 m/s, reducing significantly as the liquid front progresses down the pipeline. 

It should therefore not be surprising that it can take a long time to pre-cool a long pipeline before liquid can be transferred. Increasing the inlet pressure will not increase the mass flow rate or speed up the rate of cooldown the exit shock will just get stronger. 

It follows from these points that all transfer lines should be as short as possible. 

9 Cooldown of a Tank with Minimum Loss of Liquid 

To cool a tank down to liquid temperature efficiently, full use should be made of the cold in the cryogen, including both the latent heat of evaporation and the sensible heat of the vapour between boiling point and ambient temperature to cool the system from the bottom upwards. This can only be achieved if  

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