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EP-4735149-A1 - 2X7 ROTARY VALVE

EP4735149A1EP 4735149 A1EP4735149 A1EP 4735149A1EP-4735149-A1

Abstract

Disclosed herein are rotary valve assemblies, comprising a single rotor, for use in adsorption based separation processes. Also disclosed are adsorption based separation apparatuses including said rotary valve assemblies, and adsorption based separation processes using said adsorption based separation apparatuses.

Inventors

  • Kiffer, Micah S.
  • JONAS, Gordon
  • Whitley, Roger D.
  • BHADRA, SHUBHRA JYOTI

Assignees

  • Air Products and Chemicals, Inc.

Dates

Publication Date
20260506
Application Date
20240611

Claims (20)

  1. 1. A rotary valve assembly for use in an adsorption based separation process, the rotary valve assembly comprising: a housing having a feed port for introduction of a feed stream, a product port for withdrawal of a product stream, and a plurality of pairs of bed ports, each pair of bed ports being for connection in fluid flow communication to an adsorbent bed and consisting of a feed end bed port for sending fluid to or receiving fluid from a feed end of the adsorbent bed and a product end bed port for sending fluid to or receiving fluid from a product end of the adsorbent bed; and a rotor rotatably mounted within the housing, the rotor comprising a component having a first end surface, a side surface and a second end surface and containing a plurality of channels that are separate from each other and comprise at least a feed channel and a product channel, said component being a unitary component or a component formed of two or more parts that are rigidly attached to each other; wherein the first and second end surfaces of the rotor form flat sealing surfaces with the housing, the feed channel has a first opening in the first end surface that is in fluid flow communication with the feed port, the product channel has a first opening in the second end surface that is in fluid flow communication with the product port, and the feed channel has a second opening in the first end surface that can, via rotation of the rotor within the housing, be brought into and out of alignment and hence fluid flow communication with each feed end bed port, and the product channel has a second opening in the second end surface that can, via rotation of the rotor within the housing, be brought into and out of alignment and hence fluid flow communication with each product end bed port, such that via rotation of the rotor within the housing the second openings of the feed and product channels can be brought into and out of fluid flow communication with each pair of bed ports.
  2. 2. A rotary valve assembly as claimed in claim 1 , wherein the first opening of the feed channel is positioned at the center of the first end surface of the rotor at least substantially coaxially with the axis of rotation of the rotor, and wherein the first opening of the product channel is positioned at the center of the second end surface of the rotor at least substantially coaxially with the axis of rotation of the rotor.
  3. 3. A rotary valve assembly as claimed in claim 1 , wherein the rotary valve assembly further comprises a hollow drive shaft connected to the rotor for rotating the rotor within the housing and that forms either: a conduit between the feed port and the first opening of the feed channel for transfer of the feed stream from the feed port to the first opening of the feed channel; or a conduit between the product port and the first opening of the product channel for transfer of the product stream from the first opening of the product channel to the product port.
  4. 4. A rotary valve assembly as claimed in claim 1 , wherein: the feed end bed ports are angled outwards away from the axis of rotation of the rotor; and/or the product end bed ports are angled outwards away from the axis of rotation of the rotor.
  5. 5. A rotary valve assembly as claimed in claim 1 , wherein the second opening of the feed channel in the first end surface and the second opening of the product channel in the second end surface are positioned at the same or substantially the same circumferential and radial location of the rotor.
  6. 6. A rotary valve assembly as claimed in claim 1 , wherein the feed channel has a third opening in the first end surface that can, via rotation of the rotor within the housing, be brought into and out of alignment and hence fluid flow communication with each feed end bed port, and the product channel has a third opening in the second end surface that can, via rotation of the rotor within the housing, be brought into and out of alignment and hence fluid flow communication with each product end bed port, such that via rotation of the rotor within the housing the third openings of the feed and product channels can be brought into and out of fluid flow communication with each pair of bed ports.
  7. 7. A rotary valve assembly as claimed in claim 6, wherein the third opening of the feed channel in the first end surface and the third opening of the product channel in the second end surface are positioned at a the same or substantially the same circumferential and radial location of the rotor.
  8. 8. A rotary valve assembly as claimed in claim 1 , wherein the housing further comprises a blowdown port for withdrawal of a blowdown stream, and the plurality of channels of the rotor further comprise a first blowdown channel, the first blowdown channel having a first opening that is in fluid flow communication with the blowdown port and a second opening in the first end surface that can, via rotation of the rotor within the housing, be brought into and out of alignment and hence fluid flow communication with each feed end bed port.
  9. 9. A rotary valve assembly as claimed in claim 8, wherein the first opening of the first blowdown channel is in the side surface of the rotor, the side surface of the rotor being spaced from the housing so as to form with the housing a channel around the rotor for transfer of the blowdown stream from the first opening of the first blowdown channel to the blowdown port.
  10. 10. A rotary valve assembly as claimed in claim 8, wherein the housing further comprises a purge inlet port for introduction of a purge stream, and the plurality of channels of the rotor further comprise a purge channel separate, the purge channel having a first opening that is in fluid flow communication with the purge inlet port and a second opening in the second end surface that can, via rotation of the rotor within the housing, be brought into and out of alignment and hence fluid flow communication with each product end bed port, such that via rotation of the rotor within the housing the second openings of the purge and first blowdown channels can be brought into and out of fluid flow communication with each pair of bed ports.
  11. 11. A rotary valve assembly as claimed in claim 10, wherein the first opening of the purge channel is in the second end surface and is in the form of an annular opening that encircles, but is separate from, the first opening of the product channel.
  12. 12. A rotary valve assembly as claimed in claim 10, wherein the plurality of channels of the rotor further comprise a second blowdown channel, the second blowdown channel having a first opening that is in fluid flow communication with the blowdown port and a second opening in the first end surface that can, via rotation of the rotor within the housing, be brought into and out of alignment and hence fluid flow communication with each feed end bed port.
  13. 13. A rotary valve assembly as claimed in claim 12, wherein: the second opening of the second blowdown channel has the shape of an arcuate slot of non-uniform width, whereby the slot has a section near the leading edge of the slot where the width the slot narrows at the leading end of the section and then gradually widens towards the lagging end of the section; and/or the second opening of the first blowdown channel has the shape of an arcuate slot of non-uniform width, whereby the slot has a section near the leading edge of the slot where the width the slot narrows at the leading end of the section and then gradually widens towards the lagging end of the section.
  14. 14. A rotary valve assembly as claimed in claim 1 , wherein the plurality of channels of the rotor further comprise one or more pressure equalization channels, each pressure equalization channel having either: a first opening in the second end surface that can, via rotation of the rotor within the housing, be brought into and out of alignment and hence fluid flow communication with each product end bed port, and a second opening in the second end surface that can, via rotation of the rotor within the housing, be brought into and out of alignment and hence fluid flow communication with each product end bed port, wherein the first and second openings of the pressure equalization channel are positioned such that when first opening is in fluid flow communication with one of the product end bed ports the second opening is in fluid flow communication with another one of the product end bed ports; or a first opening in the first end surface that can, via rotation of the rotor within the housing, be brought into and out of alignment and hence fluid flow communication with each feed end bed port, and a second opening in the first end surface that can, via rotation of the rotor within the housing, be brought into and out of alignment and hence fluid flow communication with each feed end bed port, wherein the first and second openings of the pressure equalization channel are positioned such that when first opening is in fluid flow communication with one of the feed end bed ports the second opening is in fluid flow communication with another one of the feed end bed ports.
  15. 15. A rotary valve assembly as claimed in claim 1 , wherein: the feed end bed ports have circular openings facing the rotor and one or more of openings in the first end surface selected from the second opening of the feed channel, the third opening of the feed channel, the second opening of the first blowdown channel, the second opening of the second blowdown channel, and the first and/or second openings of one or more of the pressure equalization channels has an inverse circle shaped leading edge and/or lagging edge; and/or the product end bed ports have circular openings facing the rotor and one or more of the openings in the second end surface selected from the second opening of the product channel, the third opening of the product channel, the second opening of the purge channel, and the first and/or second openings of one or more of the pressure equalization channels has an inverse circle shaped leading edge and/or lagging edge.
  16. 16. A rotary valve assembly as claimed in claim 1 , wherein one or more of the channels in the rotor are fitted with a removable fitting for restricting the flow rate of fluid through the channel between two of the channel’s openings.
  17. 17. A rotary valve assembly as claimed in claim 16, wherein the removable fitting is a threaded flow control orifice inserted into the channel via an opening in the side surface of the rotor.
  18. 18. An adsorption based separation apparatus comprising: a plurality of adsorbent beds, each of the adsorbent beds having a feed end and a product end; a rotary valve assembly as claimed in claim 1 , each of the adsorbent beds being connected in fluid flow communication to a different one of the pairs of bed ports of the housing of the rotary valve assembly; and a motor for driving rotation of the rotor of the rotary valve assembly.
  19. 19. An adsorption based separation process, wherein the process uses the adsorption based separation apparatus of claim 18 and comprises: introducing a feed stream into the feed port of the rotary valve assembly, the feed stream comprising two or more components; operating the motor so as to rotate the rotor of the rotary valve assembly so as to cyclically bring each adsorbent bed into and out of fluid flow communication with the feed and product channels of the rotor; for each adsorbent bed, when the adsorbent bed is in fluid flow communication with the feed and product channels of the rotor, delivering the feed stream from the feed channel to the adsorbent bed, adsorbing one or more components of the feed stream preferentially to one or more other components of the feed stream so as to produce a product stream enriched in said one or more other components of the feed stream, and withdrawing the product stream from the adsorbent bed into the product channel; withdrawing the product stream from the product port of the rotary valve assembly; and for each adsorbent bed, during a period of time when the adsorbent bed is not in fluid flow communication with the feed and product channels of the rotor, desorbing adsorbed components of the feed gas stream from the adsorbent bed and withdrawing a blowdown stream from the adsorbent bed comprising said desorbed components.
  20. 20. An adsorption based separation process as claimed in claim 19, wherein the adsorption based separation process is a pressure swing adsorption based process, wherein: the feed stream is introduced into the feed port of the rotary valve assembly at a first pressure; and the step of desorbing adsorbed components of the feed gas stream from the adsorbent bed and withdrawing a blowdown stream from the adsorbent bed comprising said desorbed components comprises reducing the pressure in the adsorbent bed from the first pressure to a second pressure by withdrawing as a first part of the blowdown stream a blowdown gas comprising said desorbed components, and introducing a purge gas into the adsorbent bed and withdrawing as a second part of the blowdown stream and at the second pressure a blowdown gas comprising the purge gas and said desorbed components.

Description

2x7 ROTARY VALVE CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority to U.S. Non-Provisional Application 18/215,856 which was filed June 29, 2023 and is incorporated herein by reference. TECHNICAL FIELD [0002] This disclosure relates to rotary valve assemblies for use in adsorption based separation processes, to adsorption based separation apparatuses including said rotary valve assemblies, and to adsorption based separation processes using said adsorption based separation apparatuses. BACKGROUND [0003] Adsorption based separation process are processes in which one or more components of a feed stream (typically a gaseous feed stream) are separated from one or more other components of the feed stream by passing the feed stream through one or more adsorbent beds. The adsorbent (or adsorbents) present in said bed(s) is (or are) absorbent(s) of a type that preferentially adsorbs one or more components of the feed steam in comparison to one or more other components of the feed stream, such that the resulting product stream exiting the bed(s) is depleted in said preferentially adsorbed components and enriched in said components that are not preferentially adsorbed. Once the adsorbent bed(s) reach or near a point of saturation with the adsorbed component(s), either the bed(s) have to be replaced, or the bed(s) have to be regenerated by desorbing and removing the adsorbed component(s) from the bed(s). [0004] Various types of adsorption based separation processes are known in the art, including pressure swing adsorption (PSA) based process and temperature swing adsorption (TSA) based processes. In pressure swing adsorption based processes the adsorbent bed(s) are regenerated by reducing the pressure in the bed(s) to desorb the adsorbed component(s) from the bed(s), while in temperature swing adsorption based processes the adsorbent bed(s) are regenerated by increasing the temperature in the bed(s) (typically by passing a heated purge gas through the bed(s)) to desorb the adsorbed component(s) from the bed(s). Also known in the art are pressure and temperature swing adsorption (PTSA) processes, in which the adsorbent bed(s) are regenerated by both reducing the pressure and elevating the temperature in the bed(s). Exemplary pressure swing adsorption based process that are known in the art include: pressure swing adsorption (PSA) processes, in which the feed stream is introduced into the adsorbent bed(s) at elevated (above atmospheric) pressures to adsorb one or more components from the feed stream and then the pressure in the bed(s) is reduced (for example to atmospheric pressure) to regenerate the bed(s); vacuum swing adsorption (VSA) processes in which the feed stream is introduced into the adsorbent bed(s) at atmospheric pressure to adsorb one or more components from the feed stream and then the pressure in the bed(s) is reduced to sub-atmospheric pressures to regenerate the bed(s); and pressure/vacuum swing adsorption (PVSA) processes in which the feed stream is introduced into the adsorbent bed(s) at elevated (above atmospheric) pressures to adsorb one or more components from the feed stream and then the pressure in the bed(s) is reduced to sub- atmospheric pressures to regenerate the bed(s). [0005] It is typical in all such processes to use multiple beds of adsorbent and for each bed to undergo an adsorption/regeneration cycle comprising a plurality of steps, at least one which will be a feed step (during which the feed stream is introduced into the bed to adsorb component(s) of the feed stream and produce a product stream depleted in these component(s) that is withdrawn from the bed), and at least one of which will be a regeneration step (during which adsorbed component(s) are desorbed and removed from the bed), with the cycles in the beds being staggered so that different beds are on different steps of the cycle at the same time. [0006] For example, in a typical PSA based process, each bed undergoes an adsorption/regeneration cycle comprising a feed step, a blowdown step (in which the gas is evacuated from the bed reducing the pressure in the bed and desorbing adsorbed components), and a re-pressurization step (in which the pressure in the bed is increased back up to the feed pressure, typically by introducing the feed and/or some of the product into the bed). Typically, the cycle will also include a purge step, after the blowdown step and prior to the re-pressurization step, during which a purge gas (for example some of the product) is passed through the bed to assist with desorption and removal of the adsorbed component(s). Depending on the number of beds being used, the cycle may also include equalization steps, in which one bed that has completed its feed step is placed in fluid flow communication with another bed that has completed its purge step so as to equalize the pressure between the two beds, thereby partly depressurizing the bed that has completed its feed step and par