Characterization and monitoring of vacuum pressure of tank containers with multilayer insulation for cryogenic clean fuels storage and transportation

Liquid natural gas and liquid hydrogen are promising and economical clean energy sources for reducing CO2 emissions and slowing global warming. Characterization and monitoring of the vacuum pressure inside tank containers with multilayer insulation (MLI) are essential for the safe storage and convenient transportation of these cryogenic fuels. Herein, a new method for characterizing the vacuum pressure of tank containers with MLI is proposed. A theoretical analysis revealed that the temperature of the outer surface of the MLI material (T-0) is a good indicator of the vacuum pressure inside the tanks. Experimental verification was conducted using an MLI performance-testing apparatus, T-0 was measured under 10 different vacuum pressures. The results showed that when the vacuum pressure was <10(-1) Pa, T(0 )kept almost. However, when the vacuum pressure was >1 Pa, T-0 decreased sharply with the increase of vacuum pressure. The mechanism of the proposed method was also discussed based on the thermal analysis of the experimental system at different vacuum pressures. This study provides a simple and reliable method for vacuum pressure monitoring of tank containers with MLI, which allows the large-scale and safe utilization of clean energy with a low boiling temperature.

Automated summary

A new method for characterizing the vacuum pressure of tank containers with MLI is proposed, showing that the temperature of the outer surface of the MLI material is a good indicator of the vacuum pressure inside the tanks. Experimental verification and theoretical analysis confirmed the relationship between temperature and vacuum pressure.