Process swing adsorption

30 Years of PSA Technology for Hydrogen Purification
J. Stöcker and M. Whysall
UOP
Antwerp, Belgium and G.Q. Miller
UOP
Des Plaines, Illinois

Timetable of PSA Technology Development
This paper presents an overview of UOP’s PSA development work and also addresses the key role of the
PSA technology for hydrogen purification. The main development steps have been the extension of four adsorber units into systems with 10 and more adsorbers for unlimited plant capacity, the development of high-performance adsorbents to achieve the highest hydrogen recoveries, and the development of the fully automatic operation of PSA units for unattended operation.
The main PSA application has been recovery of hydrogen from a wide range of gas streams. Since its commercialisation in 1966, more than 530 PSA units have been installed worldwide. Between 1966 and
1976, the plant capacities did not exceed hydrogen product rates greater than 20,000 Nm3/h generally provided by four-bed PSA systems. The hydrogen was mainly used in chemical and petrochemical plants.
The major breakthrough of the PSA technology was achieved in 1976 with the commercialisation of
POLYBED™ PSA units. Hydrogen recoveries exceeding 90%, and the possibility of designing POLYBED
PSA units for capacities of 100,000 Nm3/h met the increasing hydrogen demand of refineries. The inherent capability of POLYBED PSA units to maintain design capacity with a reduced number of adsorbers in operation provided the on-stream reliability required for the downstream process units.
In the late 1980s, UOP added two important patented control features to the POLYBED PSA units: improved repressurisation control and automatic purity control. The improved repressurisation control allows the PSA units to be designed for “zero downtime operation.” The automatic purity control completely removes any need for operator attention. The latest control development features self-tuning of the most-critical components. Important progress has been made