Pressure Swing Adsorption
- Biogas enters.
- An adsorbing material, usually carbon molecular sieve or zeolite, preferentially adsorbs carbon dioxide and other highly adsorbed compounds at pressure (~100 psig) to upgrade the biogas.
- Systems often have multiple tanks for separation, with only one in service at a time.
- High quality biogas (renewable natural gas) exits.
![](https://americanbiogascouncil.org/wp-content/uploads/2019/03/psa_diagram.jpg)
![](https://americanbiogascouncil.org/wp-content/uploads/2019/03/psa_facility.jpg)