Experimental evidence of enhanced boil-off in isobaric mobile cryogenic vessels

Abstract

It has been postulated in the literature pertaining to the storage and transportation of cryogenic liquids that sloshing could intensify the boil-off of such liquids. However, there has been no experimental evidence in support of such postulations. Therefore, we undertook an experimental study to verify the postulation in an isobaric storage vessel subjected to an oscillatory motion. Such storage systems are in practice for the transportation of cryogenic liquids like LNG. Our study clearly showed a significant enhancement in the liquid boil-off due to the imposed motion on the storage vessel. To the best of the authors’ knowledge, the results of this study are the first ever proof that sloshing adds to the thermal energy over-and-above the heat inleak from the ambient, thereby causing a deterioration in the storability of the cryogenic liquids in mobile carriers. We found that the sloshing may have to attain a threshold frequency before its effect on boil-off becomes significant; and above this frequency, the boil-off increases with an increase in the sloshing frequency. These findings would greatly help in bettering the design of vessels used for the storage and transport of cryogenic liquids; thus, reducing the loss of precious cryogenic liquid as well as the deleterious impact on the environment.