Gas Treatment & Generation · Engineered by SorbiTech

Cryogenic ASU Pre Purification Package

Name: Cryogenic ASU Pre Purification Package
Brand: SorbiTech

Front end TSA pre purification package for cryogenic air separation units removing water, carbon dioxide, and trace hydrocarbons before the cold box.

Capacity / Flow 5,000–500,000 Nm³/h air

Design Standards ASME VIII Div.1 · PED · ATEX

Inlet Conditions 5–10 barg air · ambient temperature

Outlet Specification H₂O < 0.1 ppmv · CO₂ < 1.0 ppmv · trace HC removed

Operating Pressure (bar) 5–10

Quick Answer

A Cryogenic ASU Pre Purification Package removes water, carbon dioxide, and trace hydrocarbons from the air feed to a cryogenic air separation unit. Twin or triple TSA adsorbers charged with 13X molecular sieve hold outlet water below 0.1 ppmv and outlet carbon dioxide below 1.0 ppmv to protect the cold box main exchanger and the distillation column.

Cold Box Protection on a Graded Adsorbent Bed

The SorbiTech Cryogenic ASU Pre Purification Package sits at the front end of every cryogenic air separation plant, removing the contaminants that would freeze and accumulate in the cold box. Without effective pre purification, the cold box main heat exchanger blocks within months and the operator faces a costly defrost campaign. The package uses a graded bed: an inlet layer of activated alumina drying grade for bulk water removal at near isothermal conditions, then the main bed of SorbiTech 13X molecular sieve for residual water, carbon dioxide, and trace hydrocarbon capture.

TSA Cycle With Waste Nitrogen Regeneration

The standard cycle is temperature swing with regeneration on dry waste nitrogen returned from the cold box. The waste nitrogen is heated to 180 to 250 °C, passed through the off line vessel in counter flow, and vented after recovering the captured water and carbon dioxide. The integration with the ASU heat recovery loop makes the parasitic energy of the pre purification a fraction of the total plant energy.

Scope of Supply

The complete package includes:

Twin or triple adsorber vessels to ASME VIII or PED
Layered charge: alumina inlet (SorbiTech drying grade) plus 13X main bed (SorbiTech 13X)
Regeneration gas heater integrated with the cold box waste nitrogen loop
Switching valve manifold rated for the ASU cycle frequency
PLC or DCS sequence control with full cold box integration
ATEX or IECEx zone certification per project

Defrost Interval and Operator Economics

A correctly sized pre purification bed extends the campaign between defrosts from 1 to 3 years (typical for a poorly engineered front end) to 4 to 7 years (typical for a well engineered SorbiTech package). The reduction in defrost frequency is the single largest operating saving available to an ASU owner, recovering several hundred thousand euros per year on a mid scale plant. SorbiTech sizes the bed for the operator target defrost interval and the contracted cold box specification.

Delivery

Delivered turnkey by SorbiTech or fabricated to client drawings under SorbiTech scope, with full integration with the ASU process licensor (Air Liquide, Linde, Air Products, Praxair design standards). Sector coverage is industrial gas and air separation.