Hybrid Air Separation Method with Noncryogenic Preliminary Enrichment and Cryogenic Purification Based on a Single Component Gas or Liquid Generator

Abstract

Large quantities of high purity and high pressure nitrogen or oxygen gas are produced using a portable system. A PSA, VSA, TSA, or permeable membrane system cleans the air of water and carbon dioxide, as normally required by the cryogenic distillation cycle, but additionally, a significant amount of the oxygen or nitrogen is also removed, depending on the desired produced gas. The removal of the oxygen or nitrogen before the cryogenic process permits the distillation column to be significantly shorter than would otherwise be required. This in turn reduces the size of the equipment such that it can easily be transported and setup. Additionally, a high pressure liquid pump is used to boost the pressure of the nitrogen or oxygen immediately before it goes through the last pass of the cryogenic heat exchanger where the liquid is vaporized and the incoming gas is cooled.

1 . A height-optimized apparatus for high purity extraction of nitrogen from air comprising:
 a source of compressed air;   a non-cryogenic separation module coupled to the source of compressed air to preferentially extract a portion of the oxygen to produce an air mixture enriched in nitrogen; and   a cryogenic fractional distillation module coupled to the non-cryogenic separation module for liquefying the air mixture enriched in nitrogen and further separating the nitrogen from the air mixture enriched in nitrogen to provide high purity liquid phase extraction of the nitrogen.   
     
     
         2 .- 4 . (canceled) 
     
     
         5 . The apparatus of  claim 1  further comprising a heat exchanger coupled to the cryogenic fractional distillation module for vaporizing the high purity liquid nitrogen into a nitrogen gas. 
     
     
         6 . The apparatus of  claim 5  further comprising a pump coupled between the cryogenic fractional distillation module and the heat exchanger for pressurizing the produced high purity liquid nitrogen wherein the heat exchanger is a cryogenic fractional distillation module is pumped at high pressure by the pump through the high pressure heat exchanger to deliver high pressure nitrogen gas from the high pressure heat exchanger. 
     
     
         7 . The apparatus of  claim 1  further comprising a multiple stage feed air preparation unit coupled between the source of air and the non-cryogenic separation module to clean the air for delivery to the non-cryogenic separation module. 
     
     
         8 . The apparatus of  claim 1  where the non-cryogenic separation module is a molecular sieve type selected for its ability to remove oxygen, water, and carbon dioxide from the air. 
     
     
         9 . The apparatus of  claim 1  where the non-cryogenic separation module is a permeable membrane array selected for its ability to remove oxygen, water, and carbon dioxide from the air. 
     
     
         10 .- 13 . (canceled) 
     
     
         14 . A method for generating high purity nitrogen to an application comprising:
 providing a flow of air;   removing carbon dioxide and water to provide a cleaned flow of air;   removing a portion of the oxygen from the cleaned flow of air to form a nitrogen rich gas;   liquefying the nitrogen rich gas; and   separating the remaining oxygen from the nitrogen rich liquid in a fractional distillation column to produce a high purity liquid nitrogen.   
     
     
         15 . The method of  claim 14  further comprising vaporizing the high purity liquid nitrogen in a heat exchanger to produce a high purity low pressure nitrogen gas. 
     
     
         16 . The method of  claim 15  further comprising pressurizing of the high purity liquid nitrogen and vaporizing the high purity high pressure liquid nitrogen in a high pressure heat exchanger to produce a high purity high pressure nitrogen gas. 
     
     
         17 . The method of  claim 14  further comprising cleaning the air prior to removing carbon dioxide, water, and a portion of the oxygen from the flow of air. 
     
     
         18 .- 26 . (canceled)