Batch methods for enriching trace impurities in hydrogen gas for their further analysis

摘要

Provided herein are batch methods and devices for enriching trace quantities of impurities in gaseous mixtures, such as hydrogen fuel. The methods and devices rely on concentrating impurities using hydrogen transport membranes wherein the time period for concentrating the sample is calculated on the basis of optimized membrane characteristics, comprising its thickness and permeance, with optimization of temperature, and wherein the enrichment of trace impurities is proportional to the pressure ratio Phi/Plo and the volume ratio V1/V2, with following detection of the impurities using commonly-available detection methods.

主权项

1. A batch method for enriching trace impurities in a first sample of a hydrogen gas for their further analysis, the method comprising:
(a) sequestering the sample in an analytical chamber having a first volume V1 at an initial pressure Phi between 1000 to 12000 psig wherein the first sample contains hydrogen gas and an unknown quantity of trace impurities; (b) transferring the sample to a second chamber having a second volume V2, the second chamber containing a hydrogen transport membrane; (c) increasing concentration of trace impurities in the second chamber relative to the hydrogen gas by removing primarily hydrogen from the second chamber through the transport membrane, thus reducing the pressure in the analytical chamber from the initial to a second pressure Plo which ranges from about 10 to 1000 psig, to form a raffinate stream containing hydrogen gas with a higher concentration of trace impurities, during a time period; wherein the time period for concentrating the sample is calculated on the basis of optimized membrane characteristics, comprising its thickness and permeance, with optimization of temperature within a temperature range of above 150° C. and below 350° C., and wherein the enrichment of trace impurities is proportional to the pressure ratio Phi/Plo and the volume ratio V1/V2; (d) injecting the raffinate stream from the second chamber into an analytical device to reproducibly measure the concentration of the trace impurities, the steps a-d defining a cycle; and (e) purging the chamber after each cycle with a second sample of hydrogen gas at ambient temperature to remove any remaining trace impurities from the chamber.