Engineering technologies for fluid chemical hydrogen storage system

•A light-weight and compact gas–liquid-separator with a low profile, as required for light-duty automotive applications, was designed and tested.•Small droplets that entrain into the gas phase can form an oil film from which larger droplets can form.•The vapor pressure of liquid hydrogen carriers needs to be considered carefully in order to meet hydrogen quality guidelines. An efficient gas/liquid separator (GLS) was developed for separating hydrogen gas from spent liquid organic and inorganic hydrogen carriers onboard light-duty vehicles. The results show that the capacity of the GLS is sufficient for an 80kWe PEM fuel cell, as used in light-duty vehicle applications. A discrepancy was observed between the calculated droplet size distribution at the outlet of the GLS and the experimental results. This was explained by film formation and breakup inside the vortex finder when the GLS was operated at flow rates that exceeded its critical gas velocity.