High-purity oxygen production apparatus

Abstract

An apparatus for producing high-purity oxygen includes a heat exchanger for cooling feed air, a first rectification column, and a second rectification column. The first column reduces high-boiling-point impurities from the cooled air to produce an oxygen-containing liquid from a discharge portion. This liquid is then transferred to the second column, which reduces low-boiling-point impurities to yield the final high-purity oxygen product. A dedicated piping system connects the columns and features a branch. First piping, controlled by a first valve, directs the oxygen-containing liquid to the second column to regulate its flow rate. Second piping, controlled by a second valve, branches from the first. This arrangement allows for diversion of the liquid, enabling precise control over the properties of the feed to the second column. This control scheme ensures consistent product quality without reliance on expensive, real-time analytical instruments.

1 . A high-purity oxygen production apparatus comprising:
 a heat exchanger configured to cool a feed air;   a first rectification column comprising an introduction portion configured to introduce the feed air following cooling in the heat exchanger and a discharge portion configured to discharge an oxygen-containing liquid, the first rectification column causing a reduction in a concentration of high-boiling-point impurities having a higher boiling point than oxygen in the oxygen-containing liquid, as compared to the concentration of high-boiling-point impurities in the feed air;   a vessel comprising a nitrogen condenser located in an upper portion inside the first rectification column;   a second rectification column comprising an introduction portion configured to introduce the oxygen-containing liquid and a discharge portion configured to discharge high-purity oxygen, the second rectification column configured to cause a reduction in a concentration of low-boiling-point impurities having a lower boiling point than oxygen in the high-purity oxygen, as compared to the concentration of low-boiling-point impurities in the oxygen-containing liquid;   a first piping configured to introduce, into the second rectification column, the oxygen-containing liquid discharged by the first rectification column, the first piping comprising a first valve;   a second piping which branches from the first piping and comprises a second valve; and   an extraction piping configured to extract an oxygen-rich liquid from a bottom of the first rectification column and introduce the oxygen-rich liquid into the vessel comprising the nitrogen condenser,   wherein the first valve adjusts a flow rate of the oxygen-containing liquid introduced into the second rectification column,   wherein the second piping is in fluid communication with the extraction piping.   
     
     
         2 . The high-purity oxygen production apparatus according to  claim 1 , wherein the second piping merges with the extraction piping and supplies the oxygen-containing liquid to the extraction piping. 
     
     
         3 . The high-purity oxygen production apparatus according to  claim 1 , wherein the second piping supplies the oxygen-containing liquid to the vessel comprising the nitrogen condenser. 
     
     
         4 . The high-purity oxygen production apparatus according to  claim 1 , further comprising a flowmeter configured to measure the flow rate of the oxygen-containing liquid introduced into the second rectification column through the first piping, wherein
 a degree of opening of the first valve is increased when the flow rate of the oxygen-containing liquid measured by the flowmeter is lower than a predetermined flow rate, and the degree of opening of the first valve is reduced when the flow rate of the oxygen-containing liquid measured by the flowmeter is higher than the predetermined flow rate.   
     
     
         5 . The high-purity oxygen production apparatus according to  claim 4 , wherein the predetermined flow rate is 1-30% of the flow rate of the feed air. 
     
     
         6 . The high-purity oxygen production apparatus according to  claim 4 , wherein the flowmeter is provided in the first piping between the branch portion of the first piping and the introduction portion of the second rectification column. 
     
     
         7 . The high-purity oxygen production apparatus according to  claim 1 , further comprising an oxygen concentration meter configured to measure an oxygen concentration of the oxygen-containing liquid, or an oxygen concentration of vapour at the discharge portion of the first rectification column, wherein a degree of opening of the second valve is increased when the oxygen concentration of the oxygen-containing liquid measured by the oxygen concentration meter is lower than a predetermined concentration, and the degree of opening of the second valve is reduced when the oxygen concentration of the oxygen-containing liquid measured by the oxygen concentration meter is higher than the predetermined concentration. 
     
     
         8 . The high-purity oxygen production apparatus according to  claim 7 , wherein the predetermined concentration is in a range of 1-50%. 
     
     
         9 . The high-purity oxygen production apparatus according to  claim 7 , wherein the oxygen concentration meter is provided in the first piping between the discharge portion of the first rectification column and the branch portion of the first piping, or is provided at the discharge portion of the first rectification column. 
     
     
         10 . The high-purity oxygen production apparatus according to  claim 1 , wherein at least one additional vessel comprising a nitrogen condenser is located below the vessel comprising the nitrogen condenser located in the upper portion inside the first rectification column. 
     
     
         11 . A method for producing high-purity oxygen in the high-purity oxygen production apparatus according to  claim 1 , the method comprising the steps of:
 providing the apparatus according to  claim 1 ; and   controlling the content of impurities in produced high-purity oxygen by adjusting the oxygen concentration of the oxygen-containing liquid introduced into the second rectification column.