Online monitoring of energy content and impurities in hydrogen using a micro gas chromatograph

Hydrogen is increasingly considered as a clean alternative to natural gas, creating a need for reliable online measurements of its energy content and impurity concentrations. This study evaluates the performance of the DynamiQ-X micro gas chromatograph (GC) for monitoring factory-grade hydrogen. Helium and hydrogen were used as carrier gases in a two-unit configuration, measuring in parallel. Gas mixtures were prepared according to frequently cited impurity limits, and the system’s repeatability, accuracy and detection limits were evaluated. The measured calorific value and Wobbe index met market requirements, while the component repeatabilities were high and primarily determined by the concentration. The limits of detection (LOD) and quantification (LOQ) were low for all components, with minimal differences between both carrier gases. Notably, an oxygen LOQ below 1 ppm was achieved when hydrogen was used as the carrier gas. The results demonstrate that the equipment is suitable for online monitoring of factory-grade hydrogen and can achieve consistent and reliable analyses.