(531h) Up-Scaled Tubular High-Silica CHA-Type Zeolite Membranes for Industrial Purposes

Zeolite membranes have been a topic of much research in recent years, as a possible mean of performing efficient and low cost separations of organic molecules and gases.  NaA (LTA)-type zeolite membrane has been commercialized for dehydration of neutral solvents such as alcohols.  However, the utilization of the LTA-type zeolite membrane for dehydration has been limited to lower water concentration region (within 10wt.%), because the instability of LTA-zeolite under water rich condition.  Zeolite membrane with high stability under various conditions is required for industrial purposes such as petrochemical plants.  We developed 1m long tubular (16Φ) high-silica CHA-type zeolite membranes for industrial applications of dehydration under water-rich (over 10wt.%) and acidic feed conditions in which the LTA-type zeolite membranes cannot be utilized due to their instability. 

   The high-silica CHA-type zeolite membranes were synthesized hydrothermally using a template of adamantium hydroxide at 160 degrees centigrade for 12 - 48 hours by a secondary-growth method on the surface of tubular porous alumina supports up to 1m long.  The membranes were calcined to remove the template [1]. 

   Pervaporatiopn (PV) and vapor permeation (VP) performances of the high-silica CHA-type membranes were investigated by using hydrous feed solvents such as N-methylpyrrolidone (NMP), tetrahydrofuran (THF) and 2-propanol (IPA).  Pure water flux of PV 120°C is 32 kg/m2h and shows long-term stability.  As an example, permeation flux and separation factor in PV 130°C at feed composition of water (30wt.%)/THF (70wt.%) are 33.0 kg/m2h and 520, respectively.  This result shows the higher water permeation flux and practical separation ability for the industrial purposes.

   This study was financially supported in part by the New Energy and Industrial Technology Development Organization’s (NEDO), Japan.

[1] K. Sato et al., J. Membr. Sci. 2012, 409-410, 82-95.