Membrane permeation is a separation process involving the selective transport of gas molecules through a permeable polymeric film. Unlike many other separation processes used in the chemical engineering industry which are governed by phase equilibrium relations (e.g., distillation), membrane separation is based on the relative rates of mass transfer. A significant benefit of membrane separation is the reduction of energy requirements because a phase change is not required in the separation process.

The parameters that can be varied are:

• air pressure
   
• permeant flow rate
   
• configuration
   

• determination of separation factors
   
• effectiveness of flow configurations
   
• effects of membrane area, pressure ratio and stage separation
   

Available in the laboratory is a Permea™ Prism separation system. The unit consists of two, hollow fiber tube bundles through which gas can be permeated in any number of flow configurations. A variety of gas mixtures can be separated. Oxygen content in each stream is determined using an Oxan oxygen analyzer.

• O2 sensors can be found in the refrigerator.
   
• An instruction manual for the permeation apparatus is available.
   

2. General recommendations

References