Experimental investigation and simulation of hollow fiber membrane process for SF₆ recovery from GIS

In this present study, polyethersulfone hollow fiber membrane was used to recover sulfur hexafluoride (SF₆) from gas-insulated switchgear (GIS). SF₆, N₂ pure gas and mixed gas (12.5 vol.% of SF₆) experiment was initiated to observe permeation behavior according to temperature and pressure difference and retentate flow rate. Scanning electron microscopy was used to investigate the morphological characteristics and the structure of asymmetric hollow fibers. The permeation rates of SF₆ and N₂ were measured by the variable pressure method. As a result, permeance of N₂ was 9.5-16.3 GPU, and selectivity of N₂/SF₆ was 10.5-13.3. Moreover, the concentration of SF₆ in the retentate stream reached to 99.2% by the control of the operating condition. Based on the experimental results, tree-stage membrane process was designed using simulation program. As a result, demanded membrane area reduced about 74% according to operating condition difference.