Glycol
Dehydration Unit
Technology
Liquid absorption with glycol is one of the most common method for natural gas dehydration. The process consist in contacting the high pressure wet gas counter current with liquid desiccant (normally Tri-Ethylene-Glycol TEG) in an absorber. The column internal can be either bubble cap trays, random packed or with structured packing. The lean TEG solution (lean in water) absorbs the water. The dry gas exits at the absorber top while the rich TEG solution (rich in water) is regenerated in the glycol regeneration section.
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Different system can be used depending on the TEG concentration to be achieved. Usually the regeneration of spent glycol is obtained by reboiling the solution at atmospheric pressure. The highest reboiling temperature is limited by thermal degradation of glycol. Glycol purity that can be achieved is approximately 98.8%. When higher glycol purity is required it is necessary to operate under vacuum or adding stripping gas in order to reduce the water partial pressure.
Applications
- Gas Treatment