The primary use of mass transfer equipment in the ammonia industry occurs in the CO2 absorption and solvent regeneration columns.  The prevalent solvents are MDEA-based solvents, but hot carbonate systems and DEPG systems are also still in use.

CO2 absorber
Because packing has more capacity than trays in foaming systems, and packing dependably absorbs CO2 below 300 ppm, many of the CO2 absorbers in amine units were converted to random packing in the late 1980s and 1990s.

IMTP® provides low pressure drop and high capacity.

Koch-Glitsch often supplied IMTP® packing of 40-50 ft [12-15 m] in single beds of 40 ft [12 m] or two beds of 20-25 ft [6-7.6 m] each. 
INTALOX® ULTRA packing can be used to increase the capacity of absorbers currently packed with IMTP™ packing without loss of efficiency.  A few designs with single beds have worked well. INTALOX® ULTRA random packing provides the lowest pressure drop and highest capacity and efficiency.

FLEXIPAC® HC® high capacity structured packing combines excellent capacity and efficiency characteristics with a lower pressure drop per theoretical stage.

In absorbers with reasonable liquid rates, a few designs with structured packing, e.g. FLEXIPAC® HC® structured packing, worked well too. Customers typically select type 304 SS as the material of construction for this packing.

Solvent regeneration columns

Amine regenerators are usually trayed columns with FLEXITRAY® valve trays.

Customers typically select type 304 SS as the material of construction.

The versatile and cost effective FLEXITRAY® valve tray offers uniform vapor distribution and a wide operating range.

In hot carbonate systems, both the absorber and the desorber are frequently packed columns.

FLEXIRING® random packing is an economical and versatile industry standard with well-known performance characteristics.

Many columns use multiple tall beds of slotted ring packing, such as FLEXIRING® and HY-PAK® random packing with older style liquid distributors. 

Higher capacity packing, such as INTALOX® ULTRA, IMTP®, and CASCADE MINI-RINGS® random packings can be used to circulate more solvent.

INTALOX® high performance liquid distributors can reduce the CO2 slip.

Customers typically select type 304 SS for use in corrosive zones of these columns, but carbon steel is also used to save costs on the large volumes needed.

CASCADE MINI-RINGS® random packing achieves high capacity and low pressure drop.
DEPG systems also use large columns with multiple deep packed beds, which often use IMTP® packing. The high solvent viscosity affects the mass transfer rate and requires large equipment. Customers often select carbon steel as the material of construction to reduce costs in these large units.