Port separation for rotary bed PSA
Disclosed herein is a stator plate for a rotary bed PSA apparatus that has an exhaust slot that has first and second sections for receiving blowdown and purge exhaust gas streams, the sections being separated by a flow restriction that restricts but does not full prevent gas flow between the sections, or that has separate exhaust slots for separately receiving the blowdown and purge exhaust gas streams. Also disclosed is pressure swing adsorption (PSA) apparatus including such a stator plate, and a rotary bed PSA process using such an apparatus.
1. A rotary bed pressure swing adsorption (PSA) apparatus comprising a rotor assembly and first and second stator assemblies, wherein:
the rotor assembly is positioned between the first and second stator assemblies and comprises a plurality of adsorption beds each bed having a rotor port at either end of the bed via which gas enters or exits said bed,
the first stator assembly comprises at least one feed port, at least one exhaust port and a first stator plate having at least one feed slot for directing at least one feed gas stream from the feed port(s) into any of the rotor ports that are in alignment with the slot and at least one exhaust slot for directing flow of exhaust gas streams from any of the rotor ports that are in alignment with the slot to the exhaust port(s), and
the second stator assembly comprises at least one product port and a second stator plate having at least one product slot for directing flow of at least one product gas stream between the product port(s) and any of the rotor ports that are in alignment with the slot and at least one purge slot for directing flow of at least one purge gas stream into any of the rotor ports that are in alignment with the slot,
the rotor assembly being rotatable relative to the first and second stator assemblies so as to change the operating modes of individual adsorption beds by changing which rotor ports are in alignment with which slots in the first and second stator plates, wherein when the rotor ports of a bed are in alignment with a feed slot and/or a product slot that bed is in re-pressurization mode or feed mode, when the rotor ports of a bed are in alignment with an exhaust slot and a purge slot that bed is in purge mode, and when the rotor ports of a bed are in alignment with an exhaust slot and are not in alignment with a purge slot that bed is in blowdown mode, and
wherein either:
a) the at least one exhaust slot in the first stator plate comprises an exhaust slot that has a first section that is configured to receive a purge exhaust gas stream from at least one adsorption bed in purge mode and a second section that is configured to receive simultaneously a blowdown exhaust gas stream from at least one other adsorption bed in blowdown mode, said first section having an outlet for discharging the purge exhaust gas stream from the stator plate and said second section having a separate outlet for separately discharging the blowdown exhaust gas stream from the stator plate, the first and second sections being separated by a flow restriction that is configured to restrict but not fully prevent gas flow between the sections; or
b) the at least one exhaust slot in the first stator plate comprises a first exhaust slot that is configured to receive a purge exhaust gas stream from at least one adsorption bed in purge mode, and a separate second exhaust slot that is configured to receive simultaneously a blowdown exhaust gas stream from at least one other adsorption bed in blowdown mode, the first exhaust slot having an outlet for discharging the purge exhaust gas stream from the stator plate and the second exhaust slot having a separate outlet for separately discharging the blowdown exhaust gas stream from the stator plate.
2. The rotary bed PSA apparatus of claim 1 , wherein the at least one exhaust slot in the first stator plate comprises an exhaust slot that has a first section that is configured to receive a purge exhaust gas stream from at least one adsorption bed in purge mode and a second section that is configured to receive simultaneously a blowdown exhaust gas stream from at least one other adsorption bed in blowdown mode, said first section having an outlet for discharging the purge exhaust gas stream from the stator plate and said second section having a separate outlet for separately discharging the blowdown exhaust gas stream from the stator plate, the first and second sections being separated by a flow restriction that is configured to restrict but not fully prevent gas flow between the sections.
3. The rotary bed PSA apparatus of claim 2 , wherein said flow restriction separating the first and second sections of the exhaust slot comprises at least one physical barrier disposed within the slot that reduces the open cross sectional area of the slot at the location of the physical barrier through which gas can flow.
4. The rotary bed PSA apparatus of claim 3 , wherein said at least one physical barrier comprises a barrier disposed within the slot that extends across the full width of the slot and from the floor of the slot to a height that is less than the full height of the slot.
5. The rotary bed PSA apparatus of claim 3 , wherein the open cross sectional area of the slot at the location of the physical barrier is from 1% to 50% of the maximum cross sectional area of the slot at any other location.
6. The rotary bed PSA apparatus of claim 3 , wherein the open cross sectional area of the slot at the location of the physical barrier is from 1% to 20% of the maximum cross sectional area of the slot at any other location.
7. The rotary bed PSA apparatus of claim 3 , wherein the width of the physical barrier, in the circumferential direction of the plate, is at its narrowest point less than the diameter of the rotor ports.
8. The rotary bed PSA apparatus of claim 1 , wherein the at least one exhaust slot in the first stator plate comprises a first exhaust slot that is configured to receive a purge exhaust gas stream from at least one adsorption bed in purge mode, and a separate second exhaust slot that is configured to receive simultaneously a blowdown exhaust gas stream from at least one other adsorption bed in blowdown mode, the first exhaust slot having an outlet for discharging the purge exhaust gas stream from the stator plate and the second exhaust slot having a separate outlet for separately discharging the blowdown exhaust gas stream from the stator plate.
9. The rotary bed PSA apparatus of claim 8 , wherein the first exhaust slot is configured to receive a plurality of purge exhaust gas streams from a plurality of adsorption beds in purge mode, and/or the second exhaust slot is configured to receive a plurality of blowdown exhaust gas streams from a plurality of other adsorption beds in blowdown mode.
10. The rotary bed PSA apparatus of claim 8 , wherein the section of the stator plate separating the first and second exhaust slots has a width, in the circumferential direction of the plate, that at its narrowest point is less than the diameter of the rotor ports.
11. The rotary bed PSA apparatus of claim 1 , wherein said two separate outlets from said first and second sections of the exhaust slot or from said first and second exhaust slots are in fluid communication with the same exhaust port of the first stator assembly, said separate outlets being connected to the exhaust port via an exhaust manifold that receives both exhaust gas streams from both outlets, wherein the cross-sectional area of the exhaust manifold is greater than the cross section area of the exhaust slot or slots.
12. The rotary bed PSA apparatus of claim 1 , wherein either:
a) the at least one feed slot in the first stator plate comprises a feed slot that has a first section that is configured to direct a first feed gas stream to at least one adsorption bed in re-pressurization or feed mode and a second section that is configured to direct a second feed gas stream to at least one other adsorption bed in feed mode, said first section having an inlet for receiving the first feed gas stream and said second section having a separate inlet for separately receiving the second feed gas stream, the first and second sections being separated by flow restriction that is configured to restrict but not fully prevent gas flow between the sections; or
b) the at least one feed slot in the first stator plate comprises a first feed slot that is configured to direct a first feed gas stream to at least one adsorption bed in re-pressurization or feed mode, and a separate second feed slot that is configured to direct a second feed gas stream to at least one other adsorption bed in feed mode, the first feed slot having an inlet for receiving the first feed gas stream and the second feed slot having a separate inlet for separately receiving the second feed gas stream.
13. The rotary bed PSA apparatus of claim 1 , wherein either:
a) the at least one product slot in the second stator plate comprises a product slot that has a first section that is configured to direct a first product gas stream to at least one adsorption bed in re-pressurization mode or receive a first product gas stream from at least one adsorption bed in feed mode and a second section that is configured to receive a second product gas stream from at least one other adsorption bed in feed mode, said first section having an inlet for receiving or outlet for discharging the first product gas stream and said second section having a separate outlet for separately discharging the second product gas stream, the first and second sections being separated by flow restriction that is configured to restrict but not fully prevent gas flow between the sections; or
b) the at least one product slot in the first stator plate comprises a first product feed slot that is configured to direct a first product gas stream to at least one adsorption bed in re-pressurization mode or receive a first product gas stream from at least one adsorption bed in feed mode, and a separate second product slot that is configured to receive a second product gas stream from at least one other adsorption bed in feed mode, the first product slot having an inlet for receiving or outlet for discharging the first product gas stream and the second product slot having a separate outlet for separately discharging the second product gas stream.
14. A stator plate for a rotary bed pressure swing adsorption (PSA) apparatus, wherein the stator plate has at least one feed slot configured to be capable of directing at least one feed gas stream to at least one adsorption bed of the rotary bed PSA apparatus that is in re-pressurization or feed mode, and wherein either:
a) the stator plate further has an exhaust slot that has a first section that is configured to be capable of receiving a purge exhaust gas stream from at least one adsorption bed of the rotary bed PSA apparatus that is in purge mode and a second section that is configured to be capable of receiving simultaneously a blowdown exhaust gas stream from at least one other adsorption bed of the rotary bed PSA apparatus that is in blowdown mode, said first section having an outlet for discharging the purge exhaust gas stream from the stator plate and said second section having a separate outlet for separately discharging the blowdown exhaust gas stream from the stator plate, the first and second sections of the slot being separated by a flow restriction that is configured to restrict but not fully prevent gas flow between the sections; or
b) the stator plate further has a first exhaust slot that is configured to be capable of receiving a purge exhaust gas stream from at least one adsorption bed of the rotary bed PSA apparatus that is in purge mode, and has a separate second exhaust slot that is configured to be capable of receiving simultaneously a blowdown exhaust gas stream from at least one other adsorption bed of the rotary bed PSA apparatus that is in blowdown mode, the first exhaust slot having an outlet for discharging the purge exhaust gas stream from the stator plate and the second exhaust slot having a separate outlet for separately discharging the blowdown exhaust gas stream from the stator plate.
15. A rotary bed pressure swing adsorption (PSA) process comprising subjecting each of a plurality of adsorption beds to a PSA cycle comprising a feed step during which the adsorption bed is in feed mode, a blowdown step during which the adsorption bed is in blowdown mode, a purge step during which the adsorption bed is in purge mode, an a re-pressurization step during which the adsorption bed is in re-pressurization mode, wherein:
the adsorption beds are located in a rotor assembly that is positioned between the first and second stator assemblies, each bed having a rotor port at either end of the bed via which gas enters or exits said bed,
the first stator assembly comprises at least one feed port, at least one exhaust port and a first stator plate having at least one feed slot for directing at least one feed gas stream from the feed port(s) into any of the rotor ports that are in alignment with the slot and at least one exhaust slot for directing flow of exhaust gas streams from any of the rotor ports that are in alignment with the slot to the exhaust port(s),
the second stator assembly comprises at least one product port and a second stator plate having at least one product slot for directing flow of at least one product gas stream between the product port(s) and any of the rotor ports that are in alignment with the slot at least one purge slot for directing flow of at least one purge gas stream into any of the rotor ports that are in alignment with the slot,
the rotor assembly being rotated relative to the first and second stator assemblies so as to change the operating modes of individual adsorption beds by changing which rotor ports are in alignment with which slots in the first and second stator plates, wherein when the rotor ports of a bed are in alignment with a feed slot and/or a product slot that bed is in re-pressurization or feed mode, when the rotor ports of a bed are in alignment with an exhaust slot and a purge slot that bed is in purge mode, and when the rotor ports of a bed are in alignment with an exhaust slot and are not in alignment with a purge slot that bed is in blowdown mode, and
wherein either:
a) the at least one exhaust slot in the first stator plate comprises an exhaust slot that has a first section that receives a purge exhaust gas stream from at least one adsorption bed in purge mode and a second section that receives simultaneously a blowdown exhaust gas stream from at least one other adsorption bed in blowdown mode, said first section having an outlet for discharging the purge exhaust gas stream from the stator plate and said second section having a separate outlet for separately discharging the blowdown exhaust gas stream from the stator plate, the first and second sections of the slot being separated by a flow restriction that restricts but does not fully prevent gas flow between the sections; or
b) the at least one exhaust slot in the first stator plate comprises a first exhaust slot that receives a purge exhaust gas stream from at least one adsorption bed in purge mode, and a separate second exhaust slot that receives simultaneously a blowdown exhaust gas stream from at least one other adsorption bed in blowdown mode, the first exhaust slot having an outlet for discharging the purge exhaust gas stream from the stator plate and the second exhaust slot having a separate outlet for separately discharging the blowdown exhaust gas stream from the stator plate.
16. The rotary bed PSA process of claim 15 , wherein the at least one exhaust slot in the first stator plate comprises an exhaust slot that has a first section that receives a purge exhaust gas stream from at least one adsorption bed in purge mode and a second section that receives simultaneously a blowdown exhaust gas stream from at least one other adsorption bed in blowdown mode, said first section having an outlet for discharging the purge exhaust gas stream from the stator plate and said second section having a separate outlet for separately discharging the blowdown exhaust gas stream from the stator plate, the first and second sections of the slot being separated by a flow restriction that restricts but does not fully prevent gas flow between the sections.
17. The rotary bed PSA process of claim 16 , wherein said flow restriction separating the first and second sections of the exhaust slot comprises at least one physical barrier disposed within the slot that reduces the open cross sectional area of the slot at the location of the physical barrier through which gas can flow.
18. The rotary bed PSA process of claim 17 , wherein said at least one physical barrier comprises a barrier disposed within the slot that extends across the full width of the slot and from the floor of the slot to a height that is less than the full height of the slot.
19. The rotary bed PSA process of claim 17 , wherein the open cross sectional area of the slot at the location of the physical barrier is from 1% to 50% of the maximum cross sectional area of the slot at any other location.
20. The rotary bed PSA process of claim 17 , wherein the open cross sectional area of the slot at the location of the physical barrier is from 1% to 20% of the maximum cross sectional area of the slot at any other location.
21. The rotary bed PSA process of claim 17 , wherein the width of the physical barrier, in the circumferential direction of the plate, is at its narrowest point less than the diameter of the rotor ports.
22. The rotary bed PSA process of claim 15 , wherein the at least one exhaust slot in the first stator plate comprises a first exhaust slot that receives a purge exhaust gas stream from at least one adsorption bed in purge mode, and a separate second exhaust slot that receives simultaneously a blowdown exhaust gas stream from at least one other adsorption bed in blowdown mode, the first exhaust slot having an outlet for discharging the purge exhaust gas stream from the stator plate and the second exhaust slot having a separate outlet for separately discharging the blowdown exhaust gas stream from the stator plate.
23. The rotary bed PSA process of claim 22 , wherein the first exhaust slot receives a plurality of purge exhaust gas streams from a plurality of adsorption beds in purge mode, and/or the second exhaust slot receives a plurality of blowdown exhaust gas streams from a plurality of other adsorption beds in blowdown mode.
24. The rotary bed PSA process of claim 22 , wherein the section of the stator plate separating the first and second exhaust slots has a width, in the circumferential direction of the plate, that at its narrowest point is less than the diameter of the rotor ports.
25. The rotary bed PSA process of claim 15 , wherein said two separate outlets from said exhaust slot or said first and second exhaust slots direct the exhaust gas streams to the same exhaust port of the first stator assembly, said separate outlets being connected to the exhaust port via an exhaust manifold that receives both exhaust gas streams from both outlets, wherein the cross-sectional area of the exhaust manifold is greater than the cross section area of the exhaust slot or slots.
26. The rotary bed PSA process of claim 15 , wherein either:
a) the at least one feed slot in the first stator plate comprises a feed slot that has a first section that directs a first feed gas stream to at least one adsorption bed in re-pressurization or feed mode and a second section that directs a second feed gas stream to at least one other adsorption bed in feed mode, said first section having an inlet for receiving the first feed gas stream and said second section having a separate inlet for separately receiving the second feed gas stream, the first and second sections being separated by flow restriction that restricts but not fully prevent gas flow between the sections; or
b) the at least one feed slot in the first stator plate comprises a first feed slot that directs a first feed gas stream to at least one adsorption bed in re-pressurization or feed mode, and a separate second feed slot that directs a second feed gas stream to at least one other adsorption bed in feed mode, the first feed slot having an inlet for receiving the first feed gas stream and the second feed slot having a separate inlet for separately receiving the second feed gas stream.
27. The rotary bed PSA process of claim 15 , wherein either:
a) the at least one product slot in the second stator plate comprises a product slot that has a first section that directs a first product gas stream to at least one adsorption bed in re-pressurization mode or receives a first product gas stream from at least one adsorption bed in feed mode and a second section that receives a second product gas stream from at least one other adsorption bed in feed mode, said first section having an inlet for receiving or outlet for discharging the first product gas stream and said second section having a separate outlet for separately discharging the second product gas stream, the first and second sections being separated by flow restriction that restricts but not fully prevent gas flow between the sections; or
b) the at least one product slot in the first stator plate comprises a first product slot that directs a first product gas stream to at least one adsorption bed in re-pressurization mode or receives a first product gas stream from at least one adsorption bed in feed mode, and a separate second product slot that receives a second product gas stream from at least one other adsorption bed in feed mode, the first product slot having an inlet for receiving or outlet for discharging the first product gas stream and the second product slot having a separate outlet for separately discharging the second product gas stream.