Does anyone know what the evaporation rate of LNG storage tanks is?
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What is the normal daily evaporation rate for a 100m3 storage tank? What is the relationship with vacuum level and storage liquid level? What level of internal pressure is appropriate?
The manufacturers of LNG storage tanks usually specify a value of 0.3 percent; the daily evaporation rate is related to pressure and liquid temperature. It’s necessary to ask the manufacturer whether they have specific test data on this. Control the internal pressure by considering upper and lower limits: it shall not exceed the rated pressure of the tank’s pressure relief valve and safety valve ； It will not be lower than the rated pressure of the pressure boosting control valve or the inlet pressure of the regulator; the specific pressure range needs to be determined based on the actual operating conditions.
The theoretical value is 0.3 per thousand, but the evaporation rate is proportional to the nitrogen content
The evaporation rate of storage tanks is generally provided by the manufacturers who design those tanks; tanks designed by different manufacturers have different evaporation rates. The evaporation rate specified in our factory’s designs is 0.08%, but in reality it is slightly higher than this value. The evaporation rate is also related to the operating pressure of the storage tank; if the tank pressure is kept too low, the gas space increases and as a result the evaporation rate rises. It is appropriate to keep the pressure in the storage tank at the design value; too high a pressure poses a risk of overpressure.