Effect of nitrogen on hydrogen absorption in titanium particle beds

In order to develop a method for the separation of hydrogen and nitrogen as impurities in inert gas, a study was performed using titanium particle beds. Experiment was focused on effects of nitrogen on the amount and the rate of hydrogen absorption in case of both pre-exposure and co-flow conditions. Although nitrogen in case of the pre-exposure decreased only hydrogen capacities, co-flow nitrogen affected mainly hydrogenating rates. Variations of nitrogen toxicity with temperature and the concentrations of hydrogen and nitrogen were correlated by using an overall mass-transfer capacity coefficient. A qualitative explanation for the differences in the nitrogen toxicity was given based on the formation of a nitride film on the surfaces. In addition, removal rates of nitrogen were quantitatively evaluated. It was desirable to operate the titanium bed at 600°C for hydrogen recovery and at above 900°C for nitrogen removal.