Advancing the analysis of impurities in hydrogen by use of a novel tracer enrichment method

Abstract

A novel tracer enrichment method for concentrating the impurities in hydrogen has been developed and validated. The method calculates the enrichment factor by spiking the gas mixture with krypton and measuring the change in amount fraction before and after enrichment. This method was compared against an existing non-ideal gas law enrichment method which calculates the enrichment factor by measuring the change in pressure and temperature of the hydrogen gas mixture. The comparison was achieved by performing tests where both methods were successfully used to calculate the amount fractions of nitrogen, carbon monoxide and methane in a mixture of hydrogen with a known composition. An uncertainty budget for both methods was also developed showing that the new tracer enrichment method gives a lower uncertainty of measurement compared to the non-ideal gas law enrichment method. An additional benefit to using the tracer enrichment method is that accurate measurements can be performed even during an air leak or membrane failure. It was concluded that a combination of both of the two enrichment techniques would form the ideal measurement tool for performing accurate measurement of impurities while being able to detect leaks and monitor the enrichment factor.