Enrichment of Hydrogen from a Hydrogen/Propylene Gas Mixture Using ZIF-8/Water-Glycol Slurry

In this work, zeolitic imidazolate framework-8 (ZIF-8), a subclass of metal organic frameworks (MOFs), was dispersed in a water-glycol solution to form a porous slurry. Using this porous slurry, a tail gas mixture containing hydrogen/propylene was separated. Experiments were performed to investigate the effects of using only the solid ZIF-8 material, a ZIF-8/water slurry, a ZIF-8/glycol slurry, or a ZIF-8/water-glycol slurry on the selectivity of the separation. The experimental results show that the slurry made from ZIF-8/water-glycol (20%) achieves good gas separation. The respective influences of the solid content, initial pressure, and temperature on the separation performance were also investigated in detail. We found that lower temperature, a ZIF-8 mass fraction of 20 wt %, and a higher operation pressure are suitable for the recovering of hydrogen from a H-2/C3H6 mixture. The selectivity of C3H6 over H-2 reaches 128 at 680 kPa initial pressure. The slurries were completely reusable for at least three cycles. The structure of the ZIF-8 material was not altered after repeated separation, meaning the material can likely be reused more than three times on an industrial scale.