Apparatus for separating oxygen from ambient air

Abstract

An apparatus for separation of gases from ambient air that has at least one separation column containing an adsorbent with an inlet at a first end and an outlet at a second end, a buffer column containing an adsorbent and having a single inlet at a first end, a vacuum pump, and a valve system that connects the vacuum pump to the outlet at the first end of the separation column, and that connects the outlet at the second end of the separation column to the single inlet at the first end of the buffer column.

1 . An apparatus for separation of gases from ambient air, the apparatus comprising:
 at least one separation column containing an adsorbent, the separation column containing an inlet at a first end and an outlet at a second end;   a buffer column containing an adsorbent and having a single inlet at a first end;   a vacuum pump;   a valve system that connects the vacuum pump to the inlet at the first end of the separation column, and that connects the outlet at the second end of separation column to the single inlet at the first end of the buffer column.   
     
     
         2 . The apparatus of  claim 1 , wherein the at least one separation column and the buffer column contain an adsorbent having a high capacity for nitrogen adsorption. 
     
     
         3 . The apparatus of  claim 1 , wherein the at least one separation column and the buffer column contain an adsorbent having a total combined volume of less than 500 cc. 
     
     
         4 . The apparatus of  claim 1 , wherein the vacuum pump operates at a pressure of about 0.08 atm to about 1.0 atm. 
     
     
         5 . The apparatus of  claim 1 , further comprising:
 a battery pack connected to the separator for providing power to operate the separator and valve system.   
     
     
         6 . The apparatus of  claim 1 , further comprising:
 a plurality of separations columns, each of the columns containing an inlet at a first end and an outlet at a second end, and wherein the valve system connects the vacuum pump to the inlet at the first end of each of the plurality of separation columns, and that connects the outlet at the second end of each of the plurality of separation column to the single inlet at the first end of the buffer column.   
     
     
         7 . The apparatus of  claim 1 , wherein the adsorbent comprises an isotherm defining the nitrogen capacity as a function of nitrogen partial pressure resulting in a substantially curved line starting with a steep slope at 0 atm that greatly decreases as pressure increases to about 3 atm. 
     
     
         8 . A method of using a gas separator to separate ambient air to obtain a stream of gas containing at least 86% oxygen, the method comprising the steps:
 1) feeding adjacent ambient air at about 1 atm into a first end of a separation column filled with an adsorbent;   2) drawing oxygen rich gas from a second end of the column;   3) evacuating waste gas from the first end of the column through a vacuum pump to a pressure of less than 1 atm;   4) repeating steps 1 through 3;   wherein the separator contains less than 500 cc of the adsorbent with an isotherm defining its nitrogen capacity as a function of nitrogen partial pressure to selectively remove nitrogen from ambient air that results in oxygen rich air being produced.   
     
     
         9 . The method of  claim 8 , wherein the method is performed by a portable gas separator that is battery operated. 
     
     
         10 . The method of  claim 8 , further wherein step  3  results in a pressure of about 0.08 atm at the end of the evacuation of the waste gas. 
     
     
         11 . The method of  claim 8 , wherein as the pressure reaches about 0.3 atm during the evacuating waste gas step, the column is pressurized with oxygen rich gas through the second end to about 0.6 atm, followed by a pressurization of the column with ambient air through the first end to obtain a column pressure of about 1 atm. 
     
     
         12 . The method of  claim 11 , wherein the separation column is pressurized with oxygen rich gas that is flowing from the second end of the column during the feeding step. 
     
     
         13 . The method of  claim 11 , wherein the column is pressurized with oxygen rich gas after the oxygen purity of the oxygen rich gas has been ordered in the column such that the more pure oxygen rich gas from the second end is the last fluid to enter the column during pressurization of the column during the feed step, and the less pure oxygen rich gas from the second end of the column is the first to enter the column during pressurization. 
     
     
         14 . The method of  claim 13 , wherein the ordering of the oxygen rich gas is performed by utilizing a buffer column filled with an adsorbent having a high nitrogen capacity, the buffer column containing an inlet port on a first end of the column for controlling flow in and out of the buffer column, and thus functioning as a last in/first out (LIFO) buffer for the purity of a separated gas flowing in and out of the inlet port. 
     
     
         15 . A method of separating ambient air to obtain a stream of oxygen rich gas, the method comprising the steps:
 1) evacuating a separation column to a first pressure through a feed end of the separation column, wherein the separation column contains an adsorbent;   2) metering a flow of gas from a last in/first out (LIFO) buffer column into a product end of the separation column while continuing to evacuate the separation column to a second pressure, wherein the LIFO buffer column contains an adsorbent;   3) stopping evacuation of the separation column while continuing the flow of gas from the LIFO buffer column at a second flow rate until a third pressure is reached in the separation column;   4) pressurizing the separation column with ambient air through the feed end to a pressure of about 1 atm; and   5) feeding air into the feed end of the separation column while drawing oxygen rich gas from the product end of the separation column; and   6) repeating steps 1 through 5.   
     
     
         16 . The method of  claim 15 , wherein step 5 further comprises:
 transferring some of the oxygen rich gas to the LIFO buffer column until the LIFO buffer column is pressurized to about 1 atm.   
     
     
         17 . The method of  claim 16 , further comprising:
 feeding air into the separation column while collecting the oxygen rich gas from the product end of the separation column.   
     
     
         18 . The method of  claim 15 , wherein the first, second, and third pressures are all less than 1 atm. 
     
     
         19 . The method of  claim 15 , wherein the second pressure is 0.5 atm or less. 
     
     
         20 . The method of  claim 15 , wherein the separation column and the LIFO buffer column contain an adsorbent having a high capacity for nitrogen adsorption.