POROUS SHEET IMMOBILIZED AMINE REACTOR FOR AN INTEGRATED HEAT AND MASS EXCHANGER

BACKGROUND

[0001] The present disclosure relates to heat exchangers and, more particularly, to an integrated heat and mass exchanger with a porous sheet immobilized amine reactor.

[0002] Life support systems are an important part of manned space missions and the continued use of manned satellites in orbit. Carbon dioxide and humidity scrubbing in space suits, spacecraft and enclosed habitable environments are necessary components of such life support systems. The operability and utility of carbon dioxide and humidity scrubbing systems for space suits, spacecraft and enclosed habitable environments are at least partially based on their ability to be relatively low weight and to occupy relatively low volume.

BRIEF DESCRIPTION

[0003] According to an aspect of the disclosure, a heat and mass exchanger is provided and includes a parting sheet, a first bed disposed on a first side of the parting sheet and including an amine immobilized in sheet form and a second bed disposed on a second side of the parting sheet opposite the first side and including an amine immobilized in sheet form.

[0004] In accordance with additional and/or alternative embodiments, the first and second beds each include a flat porous sheet into which the amine is immobilized and the parting sheet includes a non-permeable parting sheet against which the flat porous sheet of each of the first and second beds is pressed.

[0005] In accordance with additional and/or alternative embodiments, the flat porous sheet of each of the first and second beds includes carbon paper and the non-permeable parting sheet includes at least one or more of aluminum and Mylar ™.

[0006] In accordance with additional and/or alternative embodiments, scrim material is interposed between the flat porous sheet of each of the first and second beds and the non-permeable parting sheet.

[0007] In accordance with additional and/or alternative embodiments, the heat and mass exchanger further includes first and second end sheets and first and second closure bars coupled with the first and second end sheets to define an enclosure. Multiple sets of the parting sheet, the first bed and the second bed are arrayed in the enclosure between the first and second end sheets and the heat and mass exchanger further includes flow passage screens interposed between neighboring ones of the multiple sets.

[0008] In accordance with additional and/or alternative embodiments, the parting sheet of each of the multiple sets and each flow passage screen are supported on the first and second closure bars.

[0009] In accordance with additional and/or alternative embodiments, fin material forms open airflow passages between neighboring ones of the multiple sets.

[0010] According to an aspect of the disclosure, a heat and mass exchanger is provided and includes a parting sheet, a first bed disposed on a first side of the parting sheet and including a porous layer with an amine embedded therein and a second bed disposed on a second side of the parting sheet opposite the first side and including a porous layer with an amine embedded therein.

[0011] In accordance with additional and/or alternative embodiments, the parting sheet is coated with the porous layer in each of the first and second beds.

[0012] In accordance with additional and/or alternative embodiments, the porous layer includes a hydrophilic coating layer.

[0013] In accordance with additional and/or alternative embodiments, the heat and mass exchanger further includes first and second end sheets and first and second closure bars coupled with the first and second end sheets to define an enclosure. Multiple sets of the parting sheet, the first bed and the second bed are arrayed in the enclosure between the first and second end sheets and the heat and mass exchanger further includes flow passage screens interposed between neighboring ones of the multiple sets.

[0014] In accordance with additional and/or alternative embodiments, the parting sheet of each of the multiple sets and each flow passage screen are supported on the first and second closure bars.

[0015] In accordance with additional and/or alternative embodiments, fin material forms open airflow passages between neighboring ones of the multiple sets.

[0016] According to an aspect of the disclosure, a heat and mass exchanger system is provided and includes a supply air conduit, a free gas conduit, a lean air conduit, a rich air conduit, a heat and mass exchanger including first beds and second beds, each of which includes immobilized amine, and a switching system. The switching system is configured to place the heat and mass exchanger in one of a first arrangement in which the first beds are disposed between the supply air conduit and the lean air conduit with the second beds disposed between the free gas conduit and the rich air conduit and a second arrangement in which the second beds are disposed between the supply air conduit and the lean air conduit with the first beds disposed between the free gas conduit and the rich air conduit.

[0017] In accordance with additional and/or alternative embodiments, the immobilized amine includes amine immobilized in sheet form.

[0018] In accordance with additional and/or alternative embodiments, the amine is immobilized in a flat porous sheet pressed against a non-permeable parting sheet and the flat porous sheet includes carbon paper and the non-permeable parting sheet includes at least one or more of aluminum and Mylar ™.

[0019] In accordance with additional and/or alternative embodiments, the immobilized amine includes amine embedded in a porous layer.

[0020] In accordance with additional and/or alternative embodiments, the amine is embedded in a porous layer coating a parting sheet and the porous layer includes a hydrophilic coating layer.

[0021] In accordance with additional and/or alternative embodiments, the heat and mass exchanger includes a first unit including the first beds and first fluid layers, a second unit including the second beds and second fluid layers, a cold fluid system configured to supply cold fluid to one of the first and second fluid layers in accordance with the heat and mass exchanger being placed in the one of the first and second arrangements and a warm fluid system configured to supply warm fluid to one of the second and first fluid layers in accordance with the heat and mass exchanger being placed in the one of the first and second arrangements.

[0022] In accordance with additional and/or alternative embodiments, the cold fluid system supplies the cold fluid to the first fluid layers and the warm fluid system supplies the warm fluid to the second fluid layers in accordance with the heat and mass exchanger being placed in the first arrangement and the cold fluid system supplies the cold fluid to the second fluid layers and the warm fluid system supplies the warm fluid to the first fluid layers in accordance with the heat and mass exchanger being placed in the second arrangement.

[0023] Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed technical concept. For a better understanding of the disclosure with the advantages and the features, refer to the description and to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] For a more complete understanding of this disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts:

[0025]FIG. 1 is a perspective view of a heat and mass exchanger in accordance with embodiments;

[0026]FIG. 2 is an exploded perspective view of a heat and mass exchanger assembly of the heat and mass exchanger of FIG. 1;

[0027]FIG. 3 is a side schematic view of a heat and mass exchanger functional unit including an immobilized amine in sheet form in accordance with embodiments;

[0028]FIG. 4 is a side schematic view of a heat and mass exchanger functional unit with amine embedded into porous layers in accordance with embodiments;

[0029]FIG. 5 is a schematic diagram of a heat and mass exchanger system in which a heat and mass exchanger is disposed between various rich and lean air conduits in accordance with embodiments; and

[0030]FIG. 6 is a schematic diagram of the heat and mass exchanger system of FIG. 5 with first and second units in accordance with embodiments.

DETAILED DESCRIPTION

[0031] Carbon dioxide and humidity scrubbing in space suits and spacecraft life support systems are necessary for manned missions. Carbon dioxide and humidity scrubbing can also be important in enclosed habitable environments, such as commercial aircraft where scrubbing can improve overall aircraft performance. Present systems typically use a swing bed mechanism and solid amine. In these cases, carbon dioxide and humidity are adsorbed onto beads that are embedded in a brazed heat and mass exchanger. Heat of adsorption is drawn away to adjacent desorbing beds using aluminum foam. System performance tends to be limited, however, by the heat conduction path to the desorbing beads which can be inefficient in certain ways. More efficient thermal coupling could improve performance of the heat and mass exchanger and offer opportunities for mass and volume reductions. When systems are provided with improved thermal coupling and applied to aircraft, the mass and volume reductions can lead to less trade-offs of increased fuel consumption.

[0032] Thus, as will be described below, an immobilized amine is provided in sheet form or immobilized directly onto parting sheets for use in a compact heat and mass exchanger configuration. Layers of the heat and mass exchanger would alternate between bed A (adsorbing from a vent loop process stream) and bed B (desorbing to vacuum or low carbon dioxide (CO2) sweep gas). By closely coupling the amine to either side of the heat and mass exchanger parting sheets, it is possible to attain very high thermal conductivity between the adsorbing amine and the desorbing amine.

[0033] In some cases, a mass exchanger system with two separate units can be provided. Both units would have amine immobilized in bed A while bed B would have liquid pumped through it. The adsorbing mass exchanger would receive CO2-laden process air on one side and chilled coolant on the other side to pull away the heat of adsorption. The desorbing bed would be exposed to vacuum or a sweep gas on one side and warmed fluid on the other side.

[0034] Amine can be immobilized in at least two or more ways. In a first example, heat and mass exchanger passages are coated with a porous coating, such as a hydrophilic coating for condensing heat exchangers, and amine is embedded into the porous coating. In a second example, amine is immobilized into flat sheets of material, such as carbon paper or other suitable porous sheet material including, but not limited to, polymers such as polystyrene, polytetrafluoroethylene, polyacrylonitrile, polymethylmethacrylate and polyetheretherketone as well as alumina, silica gel, activated carbon, other similar materials and/or combinations thereof. The flat sheets are pressed against non-permeable parting sheets such as aluminum, Mylar ™ or other suitable materials, using a scrim material or fin materials that also creates open airflow passages between the layers.

[0035] With reference to FIGS. 1 and 2, a heat and mass exchanger 101 is provided and includes a housing 102, a heat and mass exchanger assembly 103, which is housed in the housing 102 and a controllable switching system 104. As shown in FIG. 2, the heat and mass exchanger assembly 103 includes end walls 201 and 202, heat exchange elements 203 disposed between the end walls 201 and 202 to define hot fluid and cold fluid pathways and gaskets 204 disposed at each heat exchange element 203 to maintain separation between adsorbing and desorbing beds. During operations, as hot fluid and cold fluid are directed through the heat and mass exchanger assembly 103, the adsorbing side warms while the desorbing side cools with the adsorbing side and the desorbing side thermally coupled with one another. The switching system 104 is disposed and configured to direct the hot fluid and the cold fluid into each of the hot and cold fluid pathways and to periodically switch those pathways whereupon the adsorbing side becomes the desorbing side and the desorbing side becomes the adsorbing side.

[0036] With reference to FIG. 3, an integrated heat and mass exchanger functional unit 301 is provided for use as the heat and mass exchanger assembly 103 in the heat and mass exchanger 101 of FIG. 1. The integrated heat and mass exchanger functional unit 301 includes an immobilized amine in sheet form to provide for a compact heat and mass exchanger configuration. Layers of the heat and mass exchanger alternate between bed A (adsorbing from a vent loop process stream) and bed B (desorbing to vacuum or low CO2 sweep gas). By closely coupling the amine to either side of heat and mass exchanger parting sheets, it is possible to attain very high thermal conductivity between the adsorbing amine and the desorbing amine.

[0037] As shown in FIG. 3, the integrated heat and mass exchanger functional unit 301 includes a parting sheet 310, a first bed (i.e., bed A) 320 that is disposed on a first side of the parting sheet 310 and which includes an amine 321 immobilized in sheet form and a second bed (i.e., bed B) 330 that is disposed on a second side of the parting sheet 310 opposite the first side and which includes an amine 332 immobilized in sheet form. Each of the first and second beds 320 and 330 include a flat porous sheet 322 and 332 into which the amine is immobilized, the parting sheet 310 includes a non-permeable parting sheet against which the flat porous sheet 322 and 332 of each of the first and second beds 320 and 330 is pressed. In accordance with embodiments, the flat porous sheet 322 and 332 of each of the first and second beds 320 and 330 can include carbon paper or another similar type of sheet material and/or combinations thereof and the non-permeable parting sheet 310 can include at least one or more of aluminum, Mylar ™ other similar materials and/or combinations thereof. Scrim material 340 can be interposed between the flat porous sheet 310 of each of the first and second beds 320 and 330 and the parting sheet 310.

[0038] In accordance with further embodiments, the integrated heat and mass exchanger functional unit 301 can include first and second end sheets 351, 352 and first and second closure bars 361, 362 coupled with the first and second end sheets 351, 352 to define an enclosure 370. Multiple sets of the parting sheet 310, the first bed 320 and the second bed 330 can be arrayed as layers in the enclosure 370 between the first and second end sheets 351, 352. The scrim material 340 can be provided as flow passage screens interposed between neighboring ones of the multiple sets and the parting sheet 310 of each of the multiple sets and each flow passage screen (i.e., scrim material 340) can be supported on the first and second closure bars 361, 362. The scrim material 340 can also or alternatively be provided as fin material forming open airflow passages 380 between neighboring ones of the multiple sets.

[0039] With reference to FIG. 4, an integrated heat and mass exchanger functional unit 401 is provided for use as the heat and mass exchanger assembly 103 in the heat and mass exchanger 101 of FIG. 1. The integrated heat and mass exchanger functional unit 401 includes an amine that is immobilized directly onto parting sheets to provide for a compact heat and mass exchanger configuration. Layers of the heat and mass exchanger alternate between bed A (adsorbing from a vent loop process stream) and bed B (desorbing to vacuum or low CO2 sweep gas). By closely coupling the amine to the parting sheets at each of the sides thereof, it is possible to attain very high thermal conductivity between the adsorbing amine and the desorbing amine.

[0040] As shown in FIG. 4, the integrated heat and mass exchanger functional unit 401 includes a parting sheet 410, a first bed (i.e., bed A) 420 that is disposed on a first side of the parting sheet 410 and which includes a porous layer 421 with an amine 422 embedded in the porous layer 421 and a second bed (i.e., bed B) 430 that is disposed on a second side of the parting sheet 410 opposite the first side and which includes a porous layer 431 with an amine 432 embedded in the porous layer 431. In each of the first and second beds 420 and 430, the parting sheet 410 can be coated with the porous layer 422 and 432 and the porous layer 422 and 432 can include a hydrophilic coating layer.

[0041] As will be apparent to a person of ordinary skill, the integrated heat and mass exchanger functional unit 401 can be generally configured in a similar manner as the integrated heat and mass exchanger functional unit 301 and need not be described further.

[0042] With reference to FIG. 5, a heat and mass exchanger system 501 is provided with thermally-linked beds in an exemplary amine sheet reactor configuration. The heat and mass exchanger system 501 includes a supply air conduit 510, a free gas conduit 520, a lean air conduit 530, a rich air conduit 540, an integrated heat and mass exchanger 550 and a switching system 560. The heat and mass exchanger 550 includes first beds 551 and second beds 522, each of which comprises immobilized amine generally as described above with reference to integrated heat and mass exchanger functional unit 301 of FIG. 3 and the integrated heat and mass exchanger functional unit 401 of FIG. 4. The switching system 560 is coupled with the integrated heat and mass exchanger 550 and is configured to place the integrated heat and mass exchanger 550 in one of a first arrangement and a second arrangement. In the first arrangement, the first beds 551 are disposed between the supply air conduit 510 and the lean air conduit 530 with the second beds 552 disposed between the free gas conduit 520 and the rich air conduit 540. In the second arrangement, the second beds 552 are disposed between the supply air conduit 510 and the lean air conduit 530 with the first beds 551 disposed between the free gas conduit 520 and the rich air conduit 540.

[0043] The heat and mass exchanger system 501 can use an immobilized amine in sheet form as described above with reference to FIG. 3 or an amine that is immobilized directly onto parting sheets as described above with reference to FIG. 4 to provide the heat and mass exchanger system 501 with a compact heat and mass exchanger configuration. In each of the first and second arrangements, the layers of the integrated heat and mass exchanger 550 alternate between bed A, in which the corresponding layers are responsible for adsorbing from the vent loop process stream of the supply air conduit 510 and the lean air conduit 530, and bed B, in which the corresponding layers are responsible for desorbing to vacuum or low CO2 sweep gas of the free gas conduit 520 and the rich air conduit 540. The integrated heat and mass exchanger 550 is capable of very high thermal conductivity between the adsorbing amine and the desorbing amine of the bed A layers and the bed B layers.

[0044] With reference to FIG. 6, the heat and mass exchanger system 501’ is provided with separate beds with thermal regeneration in an exemplary amine sheet reactor configuration. The heat and mass exchanger system 501’ can further include a first unit 610, which includes the first beds 551 and first fluid layers 611, a second unit 620, which includes the second beds 552 and second fluid layers 621, a cold fluid system 630 and a warm fluid system 640. The cold fluid system 630 is configured to supply cold fluid to one of the first fluid layers 611 and the second fluid layers 621 in accordance with the integrated heat and mass exchanger 550 being placed in the one of the first and second arrangements. The warm fluid system 640 is configured to supply warm fluid to one of the second fluid layers 621 and the first fluid layers 611 in accordance with the integrated heat and mass exchanger 550 being placed in the one of the first and second arrangements. That is, the cold fluid system 630 supplies the cold fluid to the first fluid 611 layers and the warm fluid system 640 supplies the warm fluid to the second fluid layers 621 in accordance with the integrated heat and mass exchanger 550 being placed in the first arrangement and the cold fluid system 630 supplies the cold fluid to the second fluid layers 621 and the warm fluid system 640 supplies the warm fluid to the first fluid layers 611 in accordance with the integrated heat and mass exchanger 550 being placed in the second arrangement.

[0045] Thus, in the heat and mass exchanger system 501’ of FIG. 6, the first unit 610 and the second unit 620 can each have amine immobilized in, for example, bed A while bed B has liquid pumped through it. The adsorbing mass exchanger would receive CO2-laden process air on one side via the supply air conduit 510 and chilled coolant on the other side to pull away the heat of adsorption. The desorbing bed would be exposed to vacuum or a sweep gas on one side via the free gas conduit 520 and warmed fluid on the other side.

[0046] Technical effects and benefits of the present disclosure are the provision of a heat and mass exchanger with immobilized amine that exhibits several advantages. In terms of pressure drop, the heat and mass exchanger requires fewer 90° bends than conventional configurations and has more open flow passages without retaining screens or bed filters compared to conventional configurations. In terms of mass reductions, an amine bed can use low density parting sheet materials since the heat and mass exchanger does not rely on high thermal conductivity of the parting sheets. In terms of cycle times, cycle times for the heat and mass exchanger can be increased due to better conductance from the adsorbing to the desorbing amine, which in turn allows the unit to be smaller. In addition, costs can be reduced due to easier manufacturing methods.

[0047] The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the technical concepts in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. The embodiments were chosen and described in order to best explain the principles of the disclosure and the practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated.

[0048] While the preferred embodiments to the disclosure have been described, it will be understood that those skilled in the art, both now and in the future, may make various improvements and enhancements which fall within the scope of the claims which follow. These claims should be construed to maintain the proper protection for the disclosure first described.