Pilot-scale fabrication, separation performance and field test of tubular SSZ-13 membranes for efficient CO₂ separation

Large-area SSZ-13 membranes were reproducibly prepared on 50-cm-long commercial and alumina tubes by secondary growth. Separation performance of the long membranes were higher than that of most small-area membranes. The effects of operation parameters such as pressure, temperature, feed flow rate and CO₂ concentration on the separation performance of membranes were investigated. A mathematic model for concentration polarization index was established to evaluate the extent of concentration polarization in the single-tube and the muti-module test. A separation system with four single-tube modules connected in series was applied to field test of real biogas. The biogas could be purified to pipeline-grade natural gas (>98 mol%) by this small system at feed flow rate of 12 standard liter per minute at 1.4 MPa pressure drop. The membrane displayed long-term stability in the wet and dry biogas. This work has made an important progress toward the industrialization of zeolite membranes for gas separation.