Method and apparatus for argon recovery in a cryogenic air separation unit integrated with a pressure swing adsorption system

An apparatus for producing a purified argon product comprising:

• a cryogenic air separation unit having a higher pressure column and a lower pressure column, and an argon rectification column arrangement disposed within the lower pressure column, the cryogenic air separation unit configured to produce an impure argon stream having between about and 4% and 25% of oxygen impurities from an oxygen-argon containing stream introduced from the lower pressure column to the argon rectification column arrangement;
• an argon recovery heat exchanger configured to warm the impure argon stream to a temperature between about 200K and 300K against a stream of the purified argon stream from the pressure swing adsorption system, a waste gas stream from the pressure swing adsorption system, and a balancing air stream of purified, compressed air of the cryogenic air separation unit;
• an argon compressor or pump configured for pressurizing the impure argon stream;
• a pressure swing adsorption system configured for purifying the pressurized impure argon stream, the pressure swing adsorption system comprising an adsorbent bed having an adsorbent configured for adsorbing the oxygen impurities to produce the purified argon stream and the waste gas stream.

A method of producing a purified argon product stream in a cryogenic air separation unit, the method comprising the steps of:

• separating argon from an oxygen-argon containing stream within a lower pressure column of the cryogenic air separation unit using an argon rectification column arrangement disposed within the lower pressure column, the separation of the argon from the oxygen-argon containing stream producing an impure argon stream having between about and 4% and 25% of oxygen impurities;
• warming the impure argon stream against the purified argon product stream and against a balancing air stream of purified, compressed air;
• pressurizing the warm impure argon stream;
• and
• purifying the warm, pressurized, impure argon stream by introducing the warm, pressurized impure argon stream into a pressure swing adsorption system to produce the purified argon product stream and a waste gas stream
• wherein the balancing air stream is returned to a location upstream of a lower column turbine system of the cryogenic air separation unit after warming the impure argon stream.

An apparatus for producing a purified argon product comprising:

• a cryogenic air separation unit having a higher pressure column and a lower pressure column, and an argon rectification column arrangement disposed within the lower pressure column, the cryogenic air separation unit configured to produce an impure argon stream having between about and 4% and 25% of oxygen impurities from an oxygen-argon containing stream introduced from the lower pressure column to the argon rectification column arrangement;
• an argon condensing assembly disposed within the lower pressure column at a location above the argon rectification column arrangement and wherein the impure argon stream is an impure liquid argon stream diverted from the argon condensing assembly or a location downstream of the argon condensing assembly;
• a pump for pumping the impure liquid argon stream;
• an argon recovery heat exchanger configured to warm the pumped impure liquid argon stream to a temperature between about 200K and 300K against a purified argon stream and a balancing air stream from an incoming air purification and compression train of the cryogenic air separation unit;
• a pressure swing adsorption system configured for purifying the impure liquid argon stream, the pressure swing adsorption system comprising an adsorbent bed having an adsorbent configured for adsorbing the oxygen impurities to produce the purified argon stream and a waste gas stream;
• an air balancing circuit configured to supply the balancing air stream from a location upstream of a lower column turbine system of the cryogenic air separation unit to the argon recovery heat exchanger where it warms the impure liquid argon stream and the air balancing circuit is further configured to return the balancing air stream as a liquid air stream to the higher pressure column.

An apparatus for producing a purified argon product comprising:

• a cryogenic air separation unit having a higher pressure column and a lower pressure column, and an argon rectification column arrangement disposed within the lower pressure column, the cryogenic air separation unit configured to produce an impure argon stream having between about and 4% and 25% of oxygen impurities from an oxygen-argon containing stream introduced from the lower pressure column to the argon rectification column arrangement;
• an argon recovery heat exchanger configured to warm the impure argon stream to a temperature between about 200K and 300K against a purified argon stream and a balancing air stream from an incoming air purification and compression train of the cryogenic air separation unit;
• an argon compressor or pump configured for pressurizing the impure argon stream;
• a pressure swing adsorption system configured for purifying the impure argon stream, the pressure swing adsorption system comprising an adsorbent bed having an adsorbent configured for adsorbing the oxygen impurities to produce the purified argon stream and a waste gas stream;
• and
• a recycle conduit disposed between the pressure swing adsorption system and the argon rectification column arrangement and configured for recycling the waste gas stream from the pressure swing adsorption system and combining the recycled waste gas with the impure argon stream upstream of the pressure swing adsorption system.

An apparatus for producing a purified argon product comprising:

• a cryogenic air separation unit having a higher pressure column and a lower pressure column, and an argon rectification column arrangement disposed within the lower pressure column, the cryogenic air separation unit configured to produce an impure argon stream having between about and 4% and 25% of oxygen impurities from an oxygen-argon containing stream introduced from the lower pressure column to the argon rectification column arrangement;
• wherein the impure argon stream is an impure gaseous argon stream diverted from an upper location of the argon rectification column arrangement or upstream of an argon condensing assembly;
• an argon compressor or pump configured for pressurizing the impure argon stream;
• an argon recovery heat exchanger configured to warm the impure argon stream to a temperature between about 200K and 300K against a purified argon stream and a balancing air stream from an incoming air purification and compression train of the cryogenic air separation unit;
• a pressure swing adsorption system configured for purifying the warmed, pressurized impure argon stream, the pressure swing adsorption system comprising an adsorbent bed having an adsorbent configured for adsorbing the oxygen impurities to produce the purified argon stream and a waste gas stream;
• and
• a warm air balancing circuit configured to supply the balancing air stream from the incoming air purification and compression train of the cryogenic air separation unit to the argon recovery heat exchanger where it warms the impure argon stream and the air balancing circuit is further configured to return the balancing air stream to a location upstream of a lower column turbine system of the cryogenic air separation unit.