Gasabsorber

A gas absorber is a device used to remove one or more gaseous components from a gas stream by contacting it with a liquid absorbent. Gas absorbers are employed in natural gas processing to remove acid gases, in refining to treat process gas streams, and in environmental control to scrub emissions. They can also be used to recover valuable volatile components.

The operation relies on gas-liquid mass transfer and, in many cases, chemical reaction within the liquid. The selected absorbent is circulated and contacted with the incoming gas in a tower or column, where the gas dissolves or chemically reacts with the liquid. The cleaned gas exits at the top, while a rich liquid is drawn off for regeneration or disposal.

Common configurations include packed towers, where random packing provides large surface area for transfer, and tray or plate columns, where liquid and gas contact across discrete stages. Units may be countercurrent, where the gas and liquid flow in opposite directions to maximize transfer, and can be operated at various temperatures and pressures depending on the system.

Absorbents range from water for humidity and simple scrubbing to specialized solvents for acid gases, such as amines (MEA, DEA, MDEA), potassium carbonate, or other proprietary solvents. After absorption, the rich solvent is typically regenerated by heating in a stripper or regeneration column to release the absorbed gas for reuse or disposal, and the lean solvent is recycled.

Key design and operating considerations include solvent selection, mass-transfer performance, solvent stability, foaming and corrosion control, entrainment, energy consumption for regeneration, and environmental emissions. Gas absorbers are critical in refining, gas processing, petrochemicals, and pollution control.