What is PSA?
swing adsorption (PSA) is a technology used to separate some gas
species from a mixture of gases under pressure according to the species'
molecular characteristics and affinity for an adsorbent material. It
operates at near-ambient temperatures and differs significantly from
cryogenic distillation techniques of gas separation. Specific adsorptive
materials (e.g., zeolites, activated carbon, molecular sieves, etc.)
are used as a trap, preferentially adsorbing the target gas species at
high pressure. The process then swings to low pressure to desorb the
adsorbed material. Nowadays the PSA technology is mainly used in CANGAS
oxygen & nitrogen generators.
Applications of PSA technology
Hypoxic air fire prevention systems to produce air with a low oxygen content.
On purpose propylene plants via propane dehydrogenation. They consist of a selective medium for the preferred adsorption of methane and ethane over hydrogen.
Industrial Nitrogen generator units which employ the
PSA technique produce high purity nitrogen gas (up to 99.9995%) from a
supply of compressed air. But such PSA are more fitted to supply
intermediate ranges of purity and flows.
Capacities of such units are given in Nm³/h, normal cubic meters per hour, one Nm³/h being equivalent to 1000 liters per hour under any of several standard conditions of temperature, pressure, and humidity.
For CANGAS PSA nitrogen generator : from 0.1 Nm³/h at 95% purity, to 10000 Nm³/h at 99.9995% purity.
For CANGAS PSA oxygen generator: up to 50000 Nm³/h with a purity between 90% and 99%.
Research is currently underway for PSA to capture CO2 in large quantities from coal-fired power plants prior to geosequestration, in order to reduce greenhouse gas production from these plants.
PSA has been discussed as a future alternative to the non-regenerable sorbent technology used in space suit Primary Life Support Systems, in order to save weight and extend the operating time of the suit.