The PSA package uses Pressure Swing Adsorption. Impurities are adsorbed at high pressure and then desorbed at low pressure. The hydrogen PSA unit purifies hydrogen-rich feed gas and product high purity hydrogen (up to 99.999%) and a purge stream containing the impurities. The capacity and hydrogen recovery of the unit depend on the type and composition of the feed gas.

The package includes adsorber vessels (from 2 to more than 10 beds) as well as piping and instrumentation to purify Hydrogen and supply tail gas for compression unit. In the main mode of operation, there is always some adsorber vessels in adsorption, while the others are in depressurization, regeneration or re-pressurization.

During adsorption, feed gas enters the bottom of the adsorber, while pure hydrogen leaves from the top. At the end of adsorption, the adsorber is loaded with impurities, concentrated at the bottom and desorbtion is needed to prepare the bed for next adsorbtion. Internally this is a batch-type process. However, battery limit flows, feed, product, and off-gas are continuous.

The key part of PSA design is adsorption efficiency and lifetime which is followed by AAC in the own PSA projects by considering the highest adsorber technology like UOP.