초록 ▼

The present invention is a nitrogen pressure swing adsorption process for separating gas mixtures containing nitrogen and oxygen, such as air, using a unique gas transfer process step, continuous feed gas introduction and an appropriate isolation step with continued product purge/repressurization to

The present invention is a nitrogen pressure swing adsorption process for separating gas mixtures containing nitrogen and oxygen, such as air, using a unique gas transfer process step, continuous feed gas introduction and an appropriate isolation step with continued product purge/repressurization to achieve high purity nitrogen product of 99.9% or greater by volume nitrogen, preferably 99.99% or greater by volume of nitrogen.

대표청구항 ▼

A process for separating a nitrogen-enriched gas from a feed gas mixture containing at least nitrogen and oxygen using a plurality of beds of adsorbent that preferentially adsorb oxygen more readily than nitrogen, comprising the steps of: (a) introducing said feed gas mixture into a feed end of a fi

A process for separating a nitrogen-enriched gas from a feed gas mixture containing at least nitrogen and oxygen using a plurality of beds of adsorbent that preferentially adsorb oxygen more readily than nitrogen, comprising the steps of: (a) introducing said feed gas mixture into a feed end of a first bed of said plurality of beds of adsorbent at an elevated feed pressure and adsorbing oxygen while removing unadsorbed nitrogen-enriched gas as a product from a product end of said first bed; (b) discontinuing the introduction of said feed gas mixture into said first bed and connecting the product end of said first bed to the product end of a second bed of said plurality of beds which is at lower pressure and transferring gas from the product end of said first bed to the product end of said second bed short of equalizing the pressure in the two beds; (c) connecting the feed end of said first bed to the feed end of said second bed, during a latter portion of the transfer of gas from the product ends of said beds in step (b), to transfer gas from the feed end of said first bed to the feed end of said second bed short of equalizing the pressure in the two beds; (d) countercurrently depressurizing said first bed at a main rate of depressurization to a lowest pressure; (e) passing nitrogen-enriched gas countercurrently through said first bed to purge oxygen from said bed; (f) isolating said first bed for a predetermined period of time while supplying nitrogen-enriched gas to said first bed at a reduced flow rate compared to step (e); (g) connecting the product end of said first bed to the product end of an other bed of said plurality of beds which is at elevated feed pressure and transferring gas from the product end of said other bed to the product end of said first bed short of equalizing the pressure in the two beds; (h) connecting the feed end of said first bed to the feed end of said other bed, during a latter portion of the transfer of gas from the product ends of said beds in step (g), to transfer gas from the feed end of said other bed to the feed end of said first bed short of equalizing the pressure in the two beds; (i) further repressurizing said first bed by the introduction of product gas at the product end of said first bed; and (j) repeating these process steps in each of said plurality of beds.