Silica-zirconia membrane supported on modified alumina for hydrogen production in steam methane reforming unit. (21st June 2019)

• Record Type: Journal Article
• Authors: Akbari, Azam; Omidkhah, Mohammadreza
• Is Part Of: International journal of hydrogen energy. Volume 44:Number 31(2019)
• Page Start: 16698
• Page End: 16706
• Publication Date: 2019-06-21
• Subjects: Membrane -- Silica-zirconia -- Hydrogen production -- Hydrogen selective -- Hydrothermally stable -- CVD; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2019.04.196
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: A hydrogen-selective and hydrothermally stable membrane composed of silica-zirconia layer deposited on a modified alumina sub layer was successfully prepared. The composite membrane was used for hydrogen purification from synthesis gas in steam methane reforming process. Silica-zirconia layer was synthesized using the CVD method at 923K and atmospheric pressure while the alumina base layer was prepared via sol-gel procedure. DLS, XRD, SEM/EDX, and BET characterization techniques were used to prove that γ-alumina base and silica-zirconia layer are fabricated successfully. Using the composite membrane, hydrogen selectivity toward other gases has improved significantly. Moreover, H2 /CH4, H2 /CO, and H2 /CO2 selectivity have been increased from 700, 350 and 70 in 5 h CVD synthesized membrane to 1600, 750 and 570 for 12 h CVD synthesized membrane respectively. The synthesized Silica-Zirconia membrane successfully altered gases permeability tendency order from H2 > CH4 > CO2 > CO to H2 > CO2 > CO > CH4 which leads to better separation of the product from methane feed. Finally, hydrothermal stability test demonstrated that permeability loss in silica-zirconia CVD coated membrane for H2 is 45.7% after 48 h, while for silica CVD coated on the modified alumina approaches 92.5%. Highlights: A hydrogen selective and hydrothermally stable silica-zirconia membrane is prepared. Silica-zirconia membrane is hydrothermally more stable than silica CVD coated alumina. Humidity causes H2 permeability loss for silica-zirconia as 45.7% and silica-alumina 92.5%. Gases permeability changes from H2 > CH4 > CO2 > CO to H2 > CO2 > CO > CH4 favoring SMR process. With this new membrane a high H2 permeability of 2.3 × 10 − 7 mol/m 2 .s.Pa is achieved.