Efficient scale-up synthesis and hydrogen separation of hollow fiber DD3R zeolite membranes

Efficient hydrogen (H2) separation is highly desired from the cracked tail gas of ethylene plant. In this work, DD3R zeolite membranes have been evaluated for potential application in H2 separation under harsh conditions. We developed an efficient scale-up synthesis of hollow fiber DD3R zeolite membranes. The alkalinity of synthesis solution was optimized to endow the good reproducibility of high-quality membranes. 17 pieces of separate membranes, total 406 cm2, were synthesized in one autoclave using the industrial grade agents. Typically, the 25 cm long membrane showed CO2/CH4 selectivity of 447 and CO2 permeance of 1.55x10-7 mol m- 2 s- 1 Pa- 1. The single component permeance of H2 is 1.8 x 10-8 mol m- 2 s- 1 Pa- 1 at 303 K and feed pressure of 0.4 MPa, leading to the ideal selectivity of 124 for H2/CH4, 242 for H2/C2H4 and 424 for H2/C2H6. For the simulated cracked gas, H2 permeance and H2/CH4 separation selectivity was 1.25 x 10-8 mol m- 2 s- 1 Pa- 1 and 128, respectively. More importantly, the DD3R zeolite membrane was stable for more than 1000 h in the simulated cracked gas containing 100 ppm H2S. Together with the linear increase of H2 flux and H2/CH4 separation selectivity of 50 at high pressure of 2.1 MPa, DD3R zeolite membranes pave the way to H2 separation from ethylene industry.

Automated summary

Efficient hydrogen separation is crucial from the cracked tail gas of ethylene plant. DD3R zeolite membranes were developed for this purpose, showing high selectivity and stability under harsh conditions. The efficient scale-up synthesis method led to the production of high-quality membranes suitable for industrial applications.