ADSORPTION AIR SEPARATION UNIT WITH PURGE RECOVERY TANK
A single bed reversing blower vacuum swing adsorption air separation unit includes a purge recovery tank. This purge recovery tank is joined to an O 2 supply line downstream of the adsorber vessel or directly to the adsorber vessel opposite an inlet thereof. The purge recovery tank collects a purging charge of mostly O 2 gas towards the end of a production phase for the air separation unit. This purging charge is held by the purge recovery tank while the reversing blower reverses and the material within the adsorber vessel is recharged. Around the time that the reversible blower is re-reversed to return to a production phase, the purge recovery tank is opened to allow mostly O 2 gas from the purge tank to quickly flow back into the adsorber vessel which has a vacuum drawn thereon, to allow the air separation unit to quickly return to its production phase.
1 : An air separation unit for O 2 recovery and supply, comprising in combination:
an adsorption bed containing an adsorption material which preferentially adsorbs N 2 over O 2 ;
an intake for entry of air into the unit;
a reversible blower between said intake and said adsorption bed, said reversible blower reversible to drive gas into said adsorption bed or pull gas out of said adsorption bed;
an O 2 supply line on a side of said adsorption bed opposite said reversible blower and leading to an O 2 supply;
at least one valve on said O 2 supply line to substantially prevent back flow into said supply line from said O 2 supply and toward said adsorption bed;
a tank off of said O 2 supply line with an entrance joined to said O 2 supply line; and
a valve between said tank and said O 2 supply line.
2 : The air separation unit of claim 1 wherein said at least one valve on said O 2 supply line includes a check valve which allows flow from said O 2 supply line to said O 2 supply, but substantially prevents flow from said O 2 supply back into said O 2 supply line.
3 : The air separation unit of claim 2 wherein said O 2 supply includes an O 2 process tank with an inlet opposite an outlet, and with said inlet coupled to said O 2 supply line through said check valve and said outlet delivering O 2 from said air separation unit.
4 : The air separation unit of claim 1 wherein said valve between said tank and said O 2 supply line is a control valve.
5 : The air separation unit of claim 4 wherein said entrance of said tank is joined to said O 2 supply line at a junction in said O 2 supply line with said O 2 supply extending away from said junction in a first direction and said adsorption bed extending from said junction in a second direction spaced from said first direction.
6 : The air separation unit of claim 1 wherein a compressor is provided on said O 2 supply line downstream of said adsorption bed, said compressor increasing a pressure of oxygen within said oxygen supply line.
7 : The air separation unit of claim 6 wherein a check valve is interposed between said compressor and said adsorption bed, said check valve substantially preventing flow out of said compressor and toward said adsorption bed.
8 : A process for O 2 recovery from air, including the steps of:
operating an air separation unit having an adsorption bed containing an adsorption material which preferentially adsorbs N 2 over O 2 , an intake for entry of air into the unit, a reversible blower between the intake and the adsorption bed, the reversible blower reversible to drive gas into the adsorption bed or pull gas out of said adsorption bed, an O 2 supply line on a side of said adsorption bed opposite said reversible blower and leading to an O 2 supply, at least one valve on said O 2 supply line to substantially prevent back flow into said supply line from said O 2 supply and toward said adsorption bed, a tank off of said O 2 supply line with an entrance joined to said O 2 supply line and a valve between said tank and said O 2 supply line, the operating step causing the reversible blower to drive air through the adsorption bed and into the O 2 supply line;
opening the valve between the tank and the O 2 supply line to fill the tank with gas;
reversing the reversible blower to drive gas from the adsorption bed to the intake;
closing the valve between the tank and the O 2 supply line to hold the gas in the tank;
re-opening the valve between the tank and the O 2 supply line after a vacuum has been drawn on the adsorption bed to release the gas from the tank and back into the adsorption bed;
re-reversing the reversible blower to again drive air through the adsorption bed and into the O 2 supply line; and
re-closing the valve between the tank and the O 2 supply line.
9 : The process of claim 8 wherein said opening step occurs before said reversing step.
10 : The process of claim 8 wherein said opening step occurs no earlier than said reversing step.
11 : The process of claim 8 wherein said closing step occurs before said reversing step.
12 : The process of claim 8 wherein said closing step occurs no earlier than said reversing step.
13 : The process of claim 8 wherein said re-opening step occurs before said re-reversing step.
14 : The process of claim 8 wherein said re-opening step occurs no earlier than said re-reversing step.
15 : The process of claim 8 wherein said re-closing step occurs before said re-reversing step.
16 : The process of claim 8 wherein said re-closing step occurs no earlier than said re-reversing step.
17 : An air separation unit for O 2 recovery and supply, comprising in combination:
an adsorption bed containing an adsorption material which preferentially adsorbs N 2 over O 2 ;
an intake for entry of air into the unit;
a reversible blower between said intake and said adsorption bed, said reversible blower reversible to drive gas into said adsorption bed or pull gas out of said adsorption bed;
an O 2 supply line on a side of said adsorption bed opposite said reversible blower and leading to an O 2 supply;
at least one valve on said O 2 supply line to substantially prevent back flow into said supply line from said O 2 supply and toward said adsorption bed;
a tank with an entrance joined at least indirectly to said adsorption bed; and
a valve between said tank and said adsorption bed.
18 : The air separation unit of claim 17 wherein said at least one valve on said O 2 supply line includes a check valve which allows flow from said O 2 supply line to said O 2 supply, but substantially prevents flow from said O 2 supply back into said O 2 supply line.
19 : The air separation unit of claim 18 wherein said O 2 supply includes an O 2 process tank with an inlet opposite an outlet, and with said inlet coupled to said O 2 supply line through said check valve and said outlet delivering O 2 from said air separation unit.
20 : The air separation unit of claim 17 wherein said valve between said tank and said adsorption tank is a control valve.