The liquid nitrogen storage tank has a high evaporation rate
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Recently, it was found that the company’s liquid nitrogen storage tank (with a capacity of 50 KL and a design pressure of 1.0 MPa) has a high evaporation rate, with 20 NM3 of gaseous nitrogen being produced per hour; this translates to an evaporation rate of over 1 KL of liquid nitrogen per day. Check that there is no obvious condensation on the exterior of the liquid nitrogen tank. I would appreciate it if experts could help analyze the reasons. Please also let me know what level of vacuum should be maintained in the vacuum interlayer How much daily evaporation is considered normal for a liquid nitrogen storage tank like this? Thank you very much
Please check the vacuum level; according to Table 5 of GB18442, for vacuum powder insulation, it should be kept at ≤3 Pa. Other standards can also be used as a reference!
The safety valve of a normal liquid nitrogen storage tank should not activate. Check whether the vacuum level is within the required range, and also examine the insulation of the liquid nitrogen outlet pipeline. Poor insulation of this pipeline can easily lead to the evaporation of the liquid nitrogen stored inside it, thereby increasing the pressure within the storage tank.
Thank you to both friends for their help. Does anyone know what amount of evaporation per day is considered normal for a liquid nitrogen tank of that capacity and pressure level?
Follow procedure 18442 – your evaporation rate does not meet the requirements; check the vacuum level