Experimental investigation on hydrogen adsorption performance of composite adsorbent in the tank with high vacuum multilayer insulation

Abstract

Hydrogen is one of the main residual gases in the high vacuum multilayer insulated tank. H 2 adsorption performance of the composite adsorbent was investigated by using a test bench, an X-ray diffraction and a scanning electron microscopy. The composite adsorbent is composed of molecular sieve 5A and getter that includes the different proportion of PdO and Ag 2O. The getter shall is laid as flat as possible when fed into the tank. Leakage and outgassing rate can be decreased by 64% after placing getter. The crystal phase structure of PdO and Ag 2O in getter is unchanged by adsorption performance. Experimental results showed that the H 2 adsorption rate is high at the initial stage, and then it starts to become slow during a relatively long period. The type IV isotherms were obtained with these samples, and the H 2 adsorption principle is also discussed. The optimum percentage content of Ag 2O in the getter is 22%. Under the allowed highest pressure, the composite adsorbent that includes 15% Ag 2O, 85% PdO and molecular sieve 5A is preferentially used in the tank interlayer. The experimental results and performance analyses can be used in the design of the high vacuum multilayer insulated tank.