Study and analysis of various factors affecting evaporation loss of liquid nitrogen storage vessels and detailing of standard procedure for measurement of such loss rate

Abstract

Loss rate of Cryogenic fluid storage vessels depends on many factors like type of insulation, vacuum level of annular space, ambient temperature, degradation of MLI/absorbers/getters used in the annular space etc. It also depends on volume and pressure of the cryogenic fluid inside the container. This paper describes in detail the possible heat leak paths in a typical cryogenic fluid storage vessels, contribution of pressure, volume of the cryogenic fluid and ambient temperature in these losses, practical methods to find evaporation loss and its accuracy, causes for the deterioration of performance of these vessels, identification and detection of leak to the annular space between inner vessel and outer vessel and remedial actions to trim down the loss rate of cryogenic fluid storage vessel. It also details a model test procedure to establish standard evaporation loss rate considering all the factors.