Acid Gas Sweetening Process Description


Acid gas removal processes utilize amines or specialty solvents to remove acid gases such as H₂S and/or CO₂ from sour natural gas in order to meet the gas quality specifications. The sour gas is contacted with lean amine in the contactor tower. An acid-base reaction occurs, binding the acid gases to the amine with a weak bond. The rich amine then flows to a regenerator, where heat breaks the weak bond between the amine and the acid gas, releasing the acid gas and regenerating the amine for re-use. The acid gases exit the top of the regenerator for further treatment while the lean amine is recirculated back to the contactor in a recirculating loop.


Amine Gas Sweetening Plant Needs


  • Achieve or exceed natural gas production quotas via reliable treatment of acid gases
  • Maintain process reliability for production consistency and minimization of downtime
  • Provide consistent sales gas specification quality for H₂S and CO₂ levels
  • Minimize offgas emissions through effective acid contaminant removal from the sour gas
  • Minimize operating and maintenance costs for fouling and corrosion control



Amine Gas Sweetening Challenges Pall’s Acid Gas Sweetening Solution
  • Foaming and reduced production rates due to hydrocarbon liquid and particulate ingression into the amine loop.
  • Foaming, process efficiency loss and increased maintenance due to fouling of the contactor, lean-rich exchanger, regenerator and reboiler due to dirty amine (green, brown, or black in color)
  • Rapid cleanup need

Improve your sour gas sweetening productivity and reliability via effective liquid and solid removal upstream of the contactor to protect the amine loop.


  • KO pots, mesh pads, cyclonic devices and conventional filter-separators may not effectively remove aerosol-sized liquid hydrocarbon droplets or fine solids.
  • High efficiency SepraSol™ Plus liquid/gas coalescers and Medallion™ HP liquid/gas coalescers provide 99.999% removal at 0.3 microns per the DOP test and 1 ppb downstream per the modified ANSI/CAGI-400-1999 test. Both provide excellent foaming and fouling protection.


Reduce the gaps in productivity, reliability and maintenance cost through effective solids control in the amine loop.


  • Solid contaminants in amine systems are mostly very fine corrosion products that may not be adequately removed by filters that exhibit unloading, media migration, channeling or poor sealing.
  • A range of absolute and nominal rated filter elements is available to reduce suspended solids to <5 ppmw, keep the amine clear or pale yellow in color, and reduce related foaming and fouling issues.
  • For enhanced solids control, add filtration to the rich side. Total sour gas worker exposure will typically be lowered due to the reduced system maintenance on the rich side.


  • Apply mobile filter or liquid/liquid coalescer skids.




Amine Gas Sweetening Process Flow Diagram 

Key Application/Filter Recommendations (other applications not shown)


Application Pall Product Customer Benefits

Contactor inlet coalescer

Productivity, reliability, freedom from slug upsets
Contactor outlet coalescer Amine-free sales gas, amine cost control
Amine filter (Add rich side for enhanced performance) Productivity, reliability, maintenance cost control
Liquid hydrocarbon removal from amine Reduce upsets in downstream sulphur plant 
Depollution/cleanup filter Rapid recovery from upsets, return to productivity, reliability, cost control



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