Process for the separation of mixtures of oxygen and of nitrogen employing an adsorbent with improved porosity
AssigneeL'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude
InventorsSerge Moreau, Christian Barbe
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Abstract
The invention relates to a process for the separation of a mixture of oxygen and nitrogen into each of its constituents, including bringing the mixture to be separated, in an adsorption zone, into contact with a selective adsorbent for nitrogen, the adsorbent being an agglomerated zeolite exhibiting an Si/Al ratio lower than 5, a porosity of between 0.38 and 0.60 and a parameter a.sub.k of at least 0.5 s.sup.-1, the parameter a.sub.k characterizing the kinetics of adsorption of nitrogen on the adsorbent in the adsorption zone in accordance with the Linear Driving Force model, it being understood that when the adsorbent is a zeolite containing lithium its porosity can vary between 0.25 and 0.60.
Claims19
Process for the separation of a mixture of oxygen and nitrogen into each of its constituents, which comprises:
- bringing the mixture, in an adsorption zone, into contact with a selective adsorbent for nitrogen, said adsorbent being an agglomerated zeolite exhibiting an Si/Al ratio lower than 5, a porosity of between 0.38 and 0.60, and a parameter a.sub.k of at least 0.5 s.sup.-1, said parameter a.sub.k characterizing the kinetics of adsorption of nitrogen on said adsorbent in said adsorption zone in accordance with a Linear Driving Force model, wherein when the adsorbent is a zeolite containing lithium, the porosity ranges between 0.25 and 0.60.
Process for the separation of a gaseous effluent containing a mixture of nitrogen and oxygen, in a treatment cycle which comprises the following stages:
- a) passing the gaseous effluent into an absorption zone including a selective adsorbent for nitrogen, said adsorbent being an agglomerated zeolite exhibiting an Si/Al ratio lower than 5, a porosity of between 0.38 and 0.60, and a parameter a.sub.k, characterizing the kinetics of adsorption of nitrogen on said adsorbent in said adsorption zone in accordance with a Linear Driving Force model, of at least 0.5 s.sup.-1, wherein when the adsorbent is a zeolite containing lithium, the porosity ranges between 0.25 and 0.60 whereby the mixture of nitrogen and oxygen is brought into contact with the zeolite, a gaseous effluent enriched in oxygen is recovered at the exit of the adsorption zone, with the nitrogen selectively adsorbed on said adsorbent;
- b) desorbing the nitrogen adsorbed on the adsorbent present in the adsorption zone by lowering the partial pressure of nitrogen within the adsorption zone;
- and
- c) restoring the adsorption zone to pressure by the introduction of a stream of oxygen or air.
Dependencies are inferred from the claim text.