Regeneration gas desorbs molecular sieve beds chromatographically in the reverse order of the adsorption bed. For example, adsorbed methane and ethane would be desorbed first, then propane and heavier hydrocarbons, then carbon dioxide. This is followed by any hydrogen sulfide that might have been in the inlet gas and, lastly, by the water. The effect of the concentration of these impurities in the regeneration gas stream may be significant when regeneration gas is 10-15% of the net inlet gas.

Other Application Gas Mixture