Method of separating a mixture of gases by absorption

A method of separating a mixture of gases which comprises:

• a) absorbing a gas fraction from the mixture of gases with a solvent in an absorption zone and obtaining a resultant charged solvent;
• b) expanding the charged solvent from step a) in an expansion means to vaporize a portion of the absorbed gases and cool the solvent;
• c) passing the cooled solvent and vaporized absorbed gases from step b) into a desorption column comprising a reboiling zone heated by an external heat source and a desorbing zone, extending from above the reboiling zone along substantially the whole height of the desorption column,incorporating an internal heat exchange zone, said internal heat exchange zone extending along substantially the whole height of the desorbing zone and being above and distinct from the reboiling zone, countercurrently contacting in the desorption column the solvent from step b) with a gas fraction desorbed from the solvent and collecting a regenerated solvent from the reboiling zone;
• d) passing the regenerated solvent from the reboiling zone of the desorption column into and through the internal heat exchange zone of the desorption column and subjecting the solvent in the absorbing zone of step c) to indirect countercurrent heat exchange with the regenerated solvent;
• and
• e) recycling the regenerated solvent from the internal heat exchange zone to the absorption zone of step a).