Separation with solvent/sorbents
Separation by cryogenic distillation
Separation with membranes
Separation with Solvent/Sorbents
Separation by Cryogenic Distillation
It is a widely used technique for streams that already have a high concentration of desired gas (typically >90 %), but it is not very appropriate for more dilute gas streams.
The main advantage of the cryogenic gas separation is that it enables direct production of liquid gas, which is often very useful for certain transport options, such as transport by ship.
A major disadvantage is connected with the high amount of energy required for the refrigeration especially for dilute gas streams.
Separation with Membranes
Separation of gases with membranes relies on the different affinities of one or more gases toward the membrane material, causing one gas to permeate faster (or slower) than others. It is one of the fastest growing field for gas separation techniques, especially due to the high variety of materials which the membrane could be composed of, including microporous organic polymers, zeolites, ceramic, and metal-containing materials (for a more in-depth reading, see Yampolskii and Freeman (Yampolskii et al. 2010)).
The use of membranes for gas separation offers several benefits, probably the most valuable is the high cost efficiency (both for the mechanical simplicity of the system and for low-energy regeneration). In fact, they do not require thermal regeneration, a phase change, or active moving parts in their operation.
- Yampolskii Y, Freeman B (eds) (2010) Membrane gas separation. Wiley, Chichester, UK, 370 ppGoogle Scholar