ROTARY FLUID PROCESSING SYSTEMS AND ASSOCIATED METHODS
Rotary fluid processing systems and associated methods are disclosed. A purification system in accordance with the particular embodiment includes a rotatable adsorbent-containing heat/mass transfer element that is generally symmetric about a rotation axis, and includes multiple radial flow paths oriented transverse to the rotation axis and multiple axial flow paths oriented transverse to the radial flow paths. The axial flow paths and radial flow paths are in thermal communication with each other, and are generally isolated from fluid communication with each other at the heat transfer element. Particular embodiments can further include a housing arrangement having multiple manifolds with individual manifolds having an entry port and an exit port, and with individual manifolds having different circumferential locations relative to the rotation axis. Still further embodiments can include a seal arrangement positioned between the heat transfer element and the housing arrangement to expose the radial flow paths, but not the axial flow paths, to the entry and exit ports of one of the manifolds, and expose the axial flow paths, but not the radial flow paths, to the entry and exit ports of another of the manifolds.
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The present disclosure is directed generally to rotary fluid processing systems and associated methods, including rotary systems for removing impurities from methane-containing mixtures in a continuous flow process that employs limited valving.
BACKGROUNDSecure domestic energy supply, global warming and climate change are presently receiving significant scientific, business, regulatory, political, and media attention. According to increasing numbers of independent scientific reports, greenhouse gases impact the ozone layer and the complex atmospheric processes that re-radiate thermal energy into space, which in turn leads to global warming on Earth. Warmer temperatures in turn affect the entire ecosystem via numerous complex interactions that are not always well understood. Greenhouse gases include carbon dioxide, but also include other gases such as methane, which is about 23 times more potent than carbon dioxide as a greenhouse gas, and nitrous oxide, which is over 300 times more potent than carbon dioxide as a greenhouse gas.
In addition to the foregoing greenhouse gas concerns, there are significant concerns about secure domestic energy supplies, concerns that the United States imports over 60% of the crude oil it consumes from a few unstable regions of the globe, and concerns about the rate at which global oil reserves are being depleted. Accordingly, there is an increasing focus on finding alternative sources of energy, including renewable, less expensive, and domestic energy sources that are cleaner to produce and use. These sources include coal seam methane, coal mine gas, non-conventional gas from shale deposits, and stranded well gas. These energy sources also include the organic fractions of municipal solid waste, food processing wastes, animal wastes, restaurant wastes, agricultural wastes, and waste water treatment plant sludge.
Many of the foregoing organic waste streams can be converted to biogas via anaerobic bacteria to produce mixtures of methane. Examples include covered landfills where the landfill gas contains approximately 48% methane, 38% carbon dioxide, 12% nitrogen and oxygen, water vapor, and small amounts of numerous other compounds. Biogas from anaerobic digestion of organic waste streams consists of approximately 65% methane, 33% carbon dioxide, water vapor and small amounts of other compounds. Coal mine gas contains approximately 64% methane, 32% nitrogen, 3% carbon dioxide, water, and small amounts of other compounds. Non-conventional or shale gas contains approximately 90% methane, 8% ethane and propane, 2% carbon dioxide, water, and small amounts of other compounds. Stranded well gas has a wide range of compositions depending on the location but typically contains approximately 80% methane, 13% nitrogen, several percent ethane and propane, plus water and 2% carbon dioxide. These stranded or waste sources of methane are widely geographically distributed rather than in large, localized sources like a large gas field. With enhanced technology these distributed methane sources are being converted to liquid natural gas (LNG) for effective storage, transport, and distribution to industrial end users for more economical use of process heat fuel and transportation end users for economical and low emissions vehicle fuel for light and heavy duty vehicles.
The processes associated with producing both LNG and compressed natural gas from LNG (LCNG) include purifying the incoming methane gas stream to remove constituents such as those that freeze out in or otherwise degrade LNG process equipment. Among the well known purification techniques is selective adsorption of certain impurities on different adsorbents such as activated alumina or zeolites. In such adsorption techniques certain impurities in a process stream flowing within a vessel containing the adsorbent are physi-adsorbed onto the surface of the adsorbent thus removing the impurities from the process stream. This purification continues until the adsorbent is saturated. To continue purification of the process stream, the process stream must be switched to another identical vessel containing clean, cool adsorbent. This transfer between vessels is normally accomplished by opening and/or closing a combination of several valves to accomplish a semi-continuous purification of the process stream. In one type of adsorption purifier, the saturated adsorbent is heated by several hundred degrees Fahrenheit, e.g., to ˜500° F., to substantially decrease the selective absorptivity of the adsorbent. This heating thereby releases the impurities from the adsorbent so they can be purged from the vessel into a discharge stream before the clean adsorbent is cooled and prepared for another purification step. The heating, purging, and cooling steps accomplish regeneration of the adsorbent. This common type of adsorption purification is called temperature swing adsorption. It commonly involves two or more vessels in parallel which are interconnected by a complex set of control valves on the inlets and outlets of each vessel. The four stages of a temperature swing adsorption purification cycle are sequentially executed in each vessel nominally over a minimum period of several hours, e.g., 12 hours. One good application of temperature swing adsorption purification is to remove the carbon dioxide present in the methane mixtures from most of the distributed waste or stranded sources. The carbon dioxide must be efficiently removed to a concentration of about 100 parts per million to avoid freezing out in the cryogenic heat exchanger, a core component of a plant that produces LNG. The small, distributed nature of methane mixtures from many stranded gas wells, biomass waste streams or landfills makes the capital and operating costs associated with such unmonetized gas-to-LNG plants a key contribution to the delivered price of industrial process LNG fuel or LNG or LCNG vehicle fuel. Accordingly, there is a need for better purifier technology that simplifies the purification steps, provides continuous purification with fewer components such as valves, and thereby reduces capital and operating costs of such LNG plants and results in a less expensive methane fuel.
Several aspects of the present disclosure are directed to rotary systems and associated methods for processing methane and other gases. Well-known characteristics often associated with certain features of these systems and methods have not been shown or described in detail to avoid unnecessarily obscuring the description of the various embodiments. Those of ordinary skill in the relevant art will understand that additional embodiments may be practiced without several of the details described below, and/or may include aspects in addition to those described below.
Several of the systems described below include a generally toroidal or donut-shaped heat/mass transfer element (e.g., a adsorbent processing medium) that rotates within a housing (e.g., a hermetic housing). As the heat/mass transfer element rotates, it sequentially exposes internal process fluid and heat transfer fluid flow passages within an associated processing medium (e.g., the adsorbent) to multiple manifolds. The multiple manifolds can (a) continuously supply a process fluid (e.g., methane gas mixture) to the processing medium which treats the process fluid (e.g., by removing impurities from the methane gas), and (b) continuously restore, replenish, regenerate or rejuvenate the processing medium before it processes additional fluid. This arrangement can be used to produce a continuous flow of processed fluid, with a reduced number of cyclic valves compared to similarly-functioning batch-mode purifying devices, or even zero valves (e.g., a valveless system), and other associated benefits that will be described in further detail below.
The heat/mass transfer element 130 includes both axial flow passages 131 and radial flow passages 132 that provide excellent thermal communication between the fluids they convey and an adsorbent processing medium 141, e.g., a adsorbent processing medium. However, the axial flow passages 131 are isolated from fluid communication with the radial flow passage 132. In the simplified schematic shown in
Continuing to refer to
In an embodiment shown in
As the heat/mass transfer element 130 rotates through the first manifold 111a, the processing medium 141 can become gradually saturated with impurities or depleted or otherwise experience a reduction in its ability to remove impurities. For example, an adsorbent processing medium 141 can become saturated with the impurities removed from the input process fluid 102. Accordingly, the processing medium 141 can be regenerated to remove the adsorbed impurities at the third region 112c. In a particular embodiment, the adsorbent processing medium 141 is regenerated by heating it to temperatures high enough to reduce the absorptivity of impurities on the adsorbent to a negligible value thereby releasing the adsorbed impurities. Accordingly, the system 100 includes a heat transfer fluid flow path and heat exchanger arrangement 170 configured to heat the adsorbent processing medium 141 with a heat transfer fluid at the third region 112c. In a particular embodiment, the heat exchanger arrangement 170 can include a heater 171 that directs a heated heat transfer fluid (e.g., a regeneration gas) into the third manifold 111c through an entry port 113c, and then through the axial flow passages 131 of the heat/mass transfer element 130 in an axial direction (e.g., perpendicular to the plane of
As the heat/mass transfer element 130 continues to rotate, the adsorbent processing medium 141 is exposed to a hot purge gas at the second region 112b. In particular, hot purge gas from a hot purge fluid supply 175 passes into the second manifold 111b via an entry port 113b, and travels radially inwardly through the radial flow passages 132, as indicated by arrows R2. The purge fluid removes the impurities released from the adsorbent processing medium 141 in the third region 112c.
As the heat/mass transfer element 130 rotates further, the adsorbent processing medium 141 is exposed to the fourth manifold 111d at the fourth region 112d. In the fourth manifold 111d, the hot, clean heat/mass transfer element 130 is cooled, to prepare the adsorbent processing medium 141 to adsorb additional impurities by the time it rotates into the first manifold 111a. Accordingly, the heat exchanger arrangement 170 can include a cooler 172 that directs a cooled or cold heat transfer fluid into the fourth manifold 111d via an entry port 113d and through the axial flow passages 131 of the heat/mass transfer element 130, as indicated by arrows A2, to cool the heat/mass transfer element 130. The heat transfer fluid exits the third manifold 111c via a corresponding exit port 114d. As the heat/mass transfer element 130 continues to rotate, the cooled portion of the adsorbent processing medium 141 is again exposed to input process fluid 102 at the first region 112a. Accordingly, each portion of the adsorbent processing medium 141 is sequentially exposed to the process fluid, put into good thermal contact with a hot regeneration fluid, exposed to a hot purging fluid, and put into good thermal contact with a cold regeneration fluid.
In most cases, it is expected that the heat exchanger 170 will operate in a closed loop fashion (as discussed later with reference to
In a simplified closed-loop embodiment, illustrated in dashed lines in
In a particular embodiment, both the hermetic housing 110 and the heat/mass transfer element 130 have generally toroidal shapes, but the inner surface of the housing 110 is circular while the outer surface of the heat/mass transfer element 130 is rectangular or, in particular embodiments, square. Accordingly, the seal arrangement 150 includes seals that are shaped to fit within the gap between these surfaces, while allowing the heat/mass transfer element 130 to rotate relative to the housing 110, and while preventing or at least significantly restricting circumferential flow between the axial flow passages 131 on the one hand and the radial flow passages 132 on the other. At the full seal 151, which is located between adjacent regions 112 (
The system 300 includes a heat/mass transfer element 330 and associated processing medium 341 that rotate within a housing 310 having four manifolds 311a-311d positioned at four corresponding circumferential regions 312a-312d. Each manifold 311a-311d has a corresponding entry port 313a-313d and exit port 314a-314d. At the first manifold 311a, the input process fluid 102 is directed through the adsorbent processing medium 341 to produce an output process fluid 103 in a manner generally similar to that described above. At the third manifold 311c, the adsorbent processing medium 341 is regenerated via heating, and at the fourth manifold 311d, the adsorbent processing medium 341 is cooled, both in a manner generally similar to that described above. A heat exchanger arrangement 370 shown in
The second manifold 311b is positioned opposite the first manifold 311a, between the third manifold 311c and the fourth manifold 311d to purge desorbed contaminants from the heat/mass transfer element 330. Accordingly, the second manifold 311b receives clean hot purge fluid (e.g., clean methane) from a heated purge fluid supply 375 and directs the hot purge fluid through the radial flow passages 332, as indicated by arrows R2. As the clean hot purge fluid passes through the radial flow passages 332 of the heat/mass transfer element 330, it carries out desorbed contaminants (e.g., carbon dioxide) from the adsorbent processing medium 341. Because the heat/mass transfer element 330 and adsorbent processing medium 341 have been heated (e.g., to about 500° F.) at the third region 312c, the purge fluid is heated to the same hot temperature before passing through the adsorbent processing medium 341 in the second region 312b. The hot purge fluid can accordingly be used to preheat the heat transfer fluid at the regeneration fluid heat exchanger 377 and trim heater 377a before the heat transfer fluid enters the third region 312c. The used and still hot purge fluid can also pass through a purge fluid heat exchanger 374 where it preheats the clean incoming purge fluid before the incoming purge fluid enters the second manifold 311b. After passing through the purge fluid heat exchanger 374, the cooled used purge fluid can be used as fuel for a power generator for the system or otherwise beneficially disposed of. In a particular embodiment, the purge fluid is received from a purge fluid supply 373 that is drawn off the output process fluid 103. Accordingly, the purge fluid can include purified methane. After passing through the purge fluid heat exchanger 374, the purge fluid can pass through a trim heater 374a to reach a suitably high temperature before entering the second region 312b. Even after mixing with the desorbed contaminants at the second region 312b, the used purge fluid can still be burned to produce power, for example, at a genset 307 or other device.
One feature of the arrangement shown in
The system 300 can include other pressure equalization paths that operate in a generally similar manner to equalize pressures at other points around the circumference of the housing 310. For example, the heat/mass transfer element 330 will cool and the pressure of the residual gas in the adsorbent and radial flow segments 332 will decrease at the fourth region 312d. To reduce or prevent pressure differences between the wheel segments of the heat/mass transfer element 330, the system 300 can include a second pressure equalization path 315b and one-way valve 316 connected between the exit port 314a of the first manifold 311a, and the radial flow passages 332 within the fourth manifold 311d. This arrangement will allow an adequate amount of purified process fluid to enter the adsorbent in the radial flow passages 332 at the fourth manifold 311d, thus continuously equalizing the pressure between these two regions during cooling in the regeneration.
An advantage of the foregoing arrangement is that the entire system 300 can be operated at a single generally uniform internal pressure. For example, the internal pressure of the hermetic housing 310 can have a value of from about 80 psia to about 150 psia, and in a particular embodiment about 120 psia. In other embodiments, the internal pressure can be higher than 150 psia (e.g., 300-350 psia) provided the housing 310 and associated fluid paths and systems are designed to withstand such loads. By equalizing the internal pressure among the regions 312a-312d, the structural stresses on the system components and in particular, the demands placed on the seals, can be reduced or eliminated. Accordingly, it is expected that this arrangement will be more cost effective over the life of the system 300.
Another advantage of the foregoing arrangement is that the system 300 can operate in a continuous flow manner. In particular, input process fluid can be continuously supplied to the system 300 as the heat/mass transfer element 330 rotates, and the heat exchanger arrangement 370 can continuously operate to thermally regenerate the adsorbent processing medium 341. To facilitate a continuous operation, the sizes of the processing regions 312a-312d can be determined in a manner that enhances (e.g., optimizes) the overall efficiency of the system 300. For example, the adsorbent processing medium 341 may require less time to undergo the purge operation in the second region 312b than it requires to perform the contaminant removal adsorption process in the first region 312a. Accordingly, because the heat/mass transfer element 330 is expected to rotate continuously at a constant rate, the circumferential extent of the second region 312b can be less than the circumferential extent of the first region 312a, and is typically the smallest of the four regions. The adsorbent processing medium 341 may require more time at the third region 312c for heating and desorption, than at the fourth region 312d for cooling. Depending on factors that include specific flow rates and heat transfer coefficients, the circumferential extents of the third region 312c and the fourth region 312d can be greater or lesser than that of the first region 312a.
As described above, the housing 310 can have a ring shape and in particular embodiments, a toroidal or donut shape. The housing 310 can be manufactured using a variety of techniques, a representative one of which is shown in
Beginning with
In
One feature of the arrangements described above with reference to
From the foregoing, it will be appreciated that specific embodiments of the disclosure have been described herein for purposes of illustration, but that various modifications may be made without deviating from the disclosure. For example, several aspects of the disclosure were described in the context of processing methane to remove carbon dioxide. In other embodiments, similar systems and methods can be used to process other gases. In addition, the processes undergone by those gases need not be limited to absorption or impurity removal processes. For example, the adsorbent processing medium described above can be replaced with a processing medium having a catalyst that initiates a reaction in the process gas. One such reaction can include the combination of methane with oxygen to form carbon dioxide and water. In still further embodiments, additional heat transfer aspects can be added to the system, for example, to further cool the adsorbent processing medium (and increase its adsorptivity) before it passes into the first region described above. In particular embodiments, the radial and/or axial flow passages or paths are distributed uniformly around the heat transfer elements, and in other embodiments, the axial and/or radial flow passages/paths can be distributed non-uniformly.
In still further embodiments, the system need not include an adsorbent processing medium at all, and can instead perform processes entirely on the basis of heat transfer. For example, the heat/mass transfer element can be replaced with a heat transfer element that is cooled to cryogenic temperatures at the fourth region, and that can remove carbon dioxide from a methane gas stream by causing the carbon dioxide to precipitate and freeze on the walls of the radial (or axial) flow passages. At the third region, the carbon dioxide can be driven (e.g., sublimated) from the heat transfer element by heating the heat transfer element as discussed above. In particular embodiments, the radial and/or axial flow passages or paths are distributed uniformly around the heat transfer element, and in other embodiments, the axial and/or radial flow passages/paths can be distributed non-uniformly. More generally, the heat/mass transfer element can be replaced with an element that performs either heat transfer or mass transfer but not necessarily both.
Certain aspects of the disclosure described in the context of particular embodiments may be combined or eliminated in other embodiments. For example, certain embodiments need not include a closed loop heat exchanger arrangement, and/or need not include a purge zone. Several embodiments were described above in the context of process fluids and heat transfer fluids that include gases. In other embodiments, the process fluids and/or the heat transfer fluids can include liquids. Further, while advantages associated with certain embodiments have been described in the context of those embodiments, other embodiments may also exhibit such advantages. Not all embodiments needs necessarily exhibit such advantages to fall within the scope of the present disclosure. Accordingly, the disclosure and associated technology can encompass other embodiments not expressly described or shown herein.
Claims
1. A gas processing system, comprising:
- a housing arrangement having multiple manifolds, with individual manifolds having an entry port and an exit port, and with individual manifolds having different circumferential locations relative to a rotation axis;
- a heat/mass transfer element containing an adsorbent, positioned within the housing arrangement and rotatable relative to the housing arrangement about the rotation axis, the heat/mass transfer element including: multiple radial flow paths oriented transverse to the rotation axis; and multiple axial flow paths oriented transverse to the radial flow paths, the axial flow paths being in thermal communication with the radial flow paths, the axial flow paths being generally isolated from fluid communication with the radial flow paths at the heat/mass transfer element; and
- a seal arrangement positioned between the heat/mass transfer element and the housing arrangement to expose the radial flow paths but not the axial flow paths to the entry and exit ports of one of the manifolds, and expose the axial flow paths but not the radial flow paths to the entry and exit ports of another of the manifolds.
2. The system of claim 1 wherein the housing arrangement includes a first manifold, a second manifold, a third manifold and a fourth manifold, and wherein the seal arrangement is positioned between the heat/mass transfer element and the housing arrangement to expose the radial flow paths but not the axial flow paths to the first and second manifolds as the heat/mass transfer element rotates, and expose the axial flow paths but not the radial flow paths to the third and fourth manifolds as the heat/mass transfer element rotates.
3. The system of claim 2 wherein the third manifold is positioned between the first and second manifolds, and wherein the fourth manifold is positioned between the first and second manifolds opposite the second manifold, and wherein a point on the heat/mass transfer element is sequentially exposed to the first, third, second and fourth manifolds as the heat/mass transfer element rotates about the rotation axis.
4. The system of claim 2, further comprising a first fluid channel connected between the second and third manifolds to equalize a pressure between the second and third manifolds, and a second fluid channel connected between the first and fourth manifolds to equalize a pressure between the first and fourth manifolds.
5. The system of claim 1 wherein the heat/mass transfer element includes an adsorbent processing medium positioned along the axial flow paths or the radial flow paths, and wherein the processing medium includes zeolite.
6. The system of claim 1 wherein the heat/mass transfer element includes an adsorbent material positioned along the axial flow paths or the radial flow paths.
7. The system of claim 6 wherein the axial flow paths include axially extending tubes, and wherein the adsorbent material is positioned on outer surfaces of the tubes.
8. The system of claim 1 wherein the housing arrangement includes a housing having a generally torroidal shape with a circular cross-section.
9. The system of claim 1 wherein the housing arrangement includes a continuous circular element disposed around the rotation axis.
10. The system of claim 1, further comprising a fluid channel connected between the individual manifolds to equalize a pressure between the individual manifolds.
11. The system of claim 1 wherein the heat/mass transfer element has a generally torroidal shape with a rectangular or square cross-section.
12. The system of claim 11 wherein the heat/mass transfer element includes a first ring-shaped side at a first radial distance from the rotation axis, a second ring shaped side generally parallel to the first side and located at a second radial distance from the rotation axis, a third ring-shaped side oriented transverse to the first and second sides at a first axial location, and a fourth ring-shaped side oriented transverse to the first and second sides at a second axial location spaced apart from the first axial location, and wherein the radial flow paths extend from the first surface to the second surface, and wherein the axial flow paths extend from the third surface to the fourth surface.
13. The system of claim 1 wherein the radial flow paths are distributed in a generally uniform, continuous manner around the rotation axis.
14. The system of claim 1 wherein the axial flow paths are distributed in a generally uniform, continuous manner around the rotation axis.
15. The system of claim 1 wherein individual manifolds are in fluid communication with the heat/mass transfer element over unequal circumferential extents.
16. The system of claim 1, further comprising a driver coupled to the heat/mass transfer element to rotate the heat/mass transfer element about the rotation axis.
17. The system of claim 16 wherein the heat/mass transfer element includes a rack, and wherein the driver is coupled to a pinion that is rotatably meshed with the rack.
18. The system of claim 1, further comprising a heat transfer loop coupled between one manifold and another manifold, the heat transfer loop being positioned to direct a heat transfer fluid through the heat/mass transfer element at the one manifold and direct the heat transfer fluid exiting the one manifold to the other manifold and through the heat/mass transfer element at the other manifold.
19. The system of claim 18 wherein the heat transfer loop is positioned to direct the heat transfer fluid through the axial flow paths but not the radial flow paths.
20. A gas purification system, comprising:
- a torroidal housing having a first manifold, a second manifold opposite the first manifold, a third manifold between the first and second manifolds, and a fourth manifold opposite the third manifold, each manifold having an entry port and an exit port;
- a torroidal heat/mass transfer ring positioned within the housing and rotatable relative to the housing about a rotation axis, the heat/mass transfer ring including: multiple radial flow paths oriented along radii extending outwardly from the rotation axis; multiple axial flow paths oriented generally parallel to the rotation axis, the axial flow paths being in thermal communication with the radial flow paths, the axial flow paths being generally isolated from fluid communication with the radial flow paths at the heat/mass transfer ring; and an adsorbent material positioned within or along the radial flow paths;
- a seal arrangement positioned between the heat/mass transfer ring and the housing to expose the radial flow paths but not the axial flow paths to the entry and exit ports of the first and second manifolds as the heat/mass transfer ring rotates, and expose the axial flow paths but not the radial flow paths to the entry and exit ports of the third and fourth manifolds as the heat/mass transfer ring rotates;
- a driver operatively coupled to the heat/mass transfer ring to rotate the heat/mass transfer ring relative to the housing about the rotation axis;
- a process gas supply coupled to the entry port of the first manifold to direct process gas through the adsorbent;
- a purge gas supply coupled to the entry port of the second manifold to direct purge gas through the adsorbent; and
- a heat transfer loop coupled between the third and fourth manifolds to heat the adsorbent at the third manifold as the adsorbent rotates from the first manifold to the second manifold, and cool the adsorbent at the fourth manifold as the adsorbent rotates from the second manifold to the first manifold.
21. The system of claim 20, further comprising:
- a heater positioned in the heat transfer loop to heat fluid entering the third manifold; and;
- a cooler positioned in the heat transfer loop to cool fluid entering the fourth manifold.
22. The system of claim 20 wherein the heat/mass transfer ring includes a rack, and wherein the driver includes a motor coupled to a pinion that is rotatably meshed with the rack.
23-27. (canceled)
28. A method for processing a gas, comprising:
- at a first region, directing a process gas through an adsorbent processing medium along one of a radial axis and an axial axis;
- rotating the adsorbent processing medium about a rotation axis from the first region to a third region and directing a heat transfer fluid along the other of the radial axis and the axial axis to be in thermal contact with the adsorbent processing medium at the third region;
- rotating the adsorbent processing medium about the rotation axis from the third region to a second region and directing a purge fluid through the adsorbent processing medium along the one of the radial axis and the axial axis at the second region;
- rotating the adsorbent processing medium about the rotation axis from the second region to a fourth region and directing the heat transfer fluid along the other of the radial axis and the axial axis to be in thermal contact with the adsorbent processing medium at the fourth region; and
- rotating the adsorbent processing medium about the rotation axis from the fourth region to the first.
29. The method of claim 28 wherein rotating the adsorbent processing medium includes rotating the adsorbent processing medium in a generally continuous manner.
30. The method of claim 28 wherein directing a heat transfer fluid includes directing a heat transfer fluid that includes the process gas as a constituent.
31. The method of claim 28, further comprising simultaneously maintaining portions of the adsorbent processing medium at the first, second, third and fourth regions at approximately the same pressure.
32. The method of claim 31 wherein the pressure is from about 80 psi to about 150 psi.
33. The method of claim 28, further comprising equalizing a pressure difference between the third and second regions, caused by different temperatures in the third and second regions, by allowing a controlled amount of fluid to pass between the third and second regions.
34. The method of claim 28, further comprising equalizing a pressure difference between the first and fourth regions, caused by different temperatures in the first and fourth regions, by allowing a controlled amount of fluid to pass between the first and fourth regions.
35. The method of claim 28 wherein directing the process gas through the adsorbent processing medium includes directing a methane-containing process gas through the adsorbent processing medium to remove impurities from the methane.
36. The method of claim 28 further comprising exposing the adsorbent processing medium to environments in individual ones of the regions for different periods of time, while rotating the adsorbent processing medium at a generally constant rate.
37-48. (canceled)
Type: Application
Filed: Dec 16, 2010
Publication Date: Jun 21, 2012
Applicant: Prometheus Technologies, LLC (Redmond, WA)
Inventors: John A. Barclay (Redmond, WA), Tadeusz Szymanski (Lynnwood, WA), Lenard J. Stoltman (North Bend, WA), Kathryn Oseen-Senda (Seattle, WA), Hunter A. Chumbley (Bonney Lake, WA)
Application Number: 12/970,865
International Classification: B01D 53/08 (20060101);