Gas separation can refer to any of a number of techniques used to separate gases, either to give multiple products or to purify a single product.
Pressure swing adsorption (PSA) pressurizes and depressurizes a multicomponent gas around an adsorbent medium to selectively adsorb some components of a gas while leaving other components free-flowing.
[2] PSA and VSA techniques may be combined and are called "vacuum pressure swing adsorption" (VPSA) in this case.
Temperature swing adsorption (TSA) is similar to other swing adsorption techniques but cycles the temperature of the adsorbent bed-gas system instead of the gas pressure to achieve separation.
[2] Cryogenic distillation is typically only used for very high volumes because of its nonlinear cost-scale relationship, which makes the process more economical at larger scales.