COUNTERFLOW AIR CONTACTOR FOR MASS TRANSFER

Abstract

A device and method for removing pollutants from the air including a reaction unit containing a reaction fluid dispersion medium such as film fill, a reaction fluid distribution system for distributing an aqueous reaction solution over the reaction fluid dispersion medium, and an air mover, located above the reaction fluid distribution system and reaction fluid dispersion medium, for drawing or forcing air into the reaction unit to contact the sodium or potassium hydroxide. The pollutant in the air reacts with the aqueous reaction solution to form an aqueous reaction product thus removing the pollutant from the air. The device may include humidifiers to humidify the ambient air before it contacts the reaction fluid.

Claims

1. An air contactor configured for large-scale and continuous removal of a pollutant from ambient air comprising: a tower frame located above a reaction fluid basin, a reaction fluid dispersion medium supported in said tower frame; a reaction fluid distribution system located in said tower frame and above said reaction fluid dispersion medium and configured to distribute a reaction fluid over said reaction fluid dispersion medium; a fan supported by said tower frame and configured to draw or force ambient air through said reaction fluid dispersion medium as said reaction fluid distribution system is distributing said reaction fluid over said reaction fluid dispersion medium; said reaction fluid basin located beneath said tower frame and configured to catch a reaction product from a reaction between said reaction fluid and the pollutant in said ambient air as well as unreacted reaction fluid wherein said reaction fluid distribution system and said reaction fluid dispersion medium are located beneath said fan.

2. An air contactor according to claim 1, wherein said tower frame defines a plenum beneath a diameter of said fan, said air contactor further comprising two humidifier sections of said tower frame flanking said plenum, said two humidifier sections each comprising water dispersion media supported in said frame and a water distribution system located over said water dispersion media.

3. An air contactor according to claim 1, wherein said reaction fluid distribution system comprises a reaction fluid header connected to reaction fluid distribution pipes having spray nozzles connected thereto.

4. An air contactor according to claim 1, wherein the pollutant is carbon dioxide.

5. An air contactor according to claim 1, wherein the reaction fluid is selected from the group consisting of sodium hydroxide and potassium hydroxide.

6. An air contactor according to claim 1, wherein the tower frame and fan are fiberglass and the basins are hydroxide and carbonate corrosion resistant material.

7. An air contactor according to claim 1 wherein said reaction fluid dispersion medium is film fill.

8. An air contactor according to claim 2 wherein said water dispersion medium is splash fill.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 is a cross-sectional side view of an air contactor according to a first embodiment of the invention.

[0028] FIG. 2 is a cross-sectional front view of an air contactor according to the embodiment shown in FIG. 1.

[0029] FIG. 3 is a schematic plan view of an air contactor according to a second embodiment of the invention.

[0030] FIG. 4 is a cross-section elevation view of an air contactor according to the embodiment of FIG. 3.

[0031] FIG. 5 is an endwall elevation view of an air contactor according to the embodiment of FIGS. 3 and 4.

[0032] FIG. 6 is a cross-section elevation view of an air contactor according to a third embodiment of the invention.

[0033] Features in the attached drawings are numbered with the following reference numerals:

TABLE-US-00001 1 Air contactor module 3 Reaction unit 4 Air inlet 5 Water humidifiers 7 Air mover/fan 9 Inlet louvers 11 Plenum 13 Splash Fill 15 Water distribution system 17 Water header 19 Water spray nozzles 21 Water basin 23 Water circulation pumps 25 K/Na Hydroxide distribution system 27 Riser 29 Feed pipe 31 K/Na Hydroxide Header 33 K/Na Hydroxide spray nozzles 35 K/Na Carbonate basin 37 Film Fill 39 Drift Eliminators 43 Water supply pipe 47 Fan shroud 49 Fan deck 51 Safety railing 53 Corrugated sheathing/casing 55 Stairway

DETAILED DESCRIPTION

[0034] A first exemplary embodiment of the invention is shown in FIGS. 1 and 2. Air contactor 1 of this embodiment features a reaction unit 3 centrally located and flanked by humidifiers 5. A fan 7 or other air mover is situated atop the reaction unit 3 to draw air through air inlets 4 in the side of the humidifiers 5 via air inlet louvers 9 and into the plenum 11.

[0035] The humidifiers 5 are provided with splash fill 13, and a water distribution system 15 is located above the splash fill 13. The water distribution system 15 includes water header 17 and water spray nozzles 19, although any type of distribution system may be used. The bottom of the humidifiers 5 features a water collection basin 21 where the water distributed by the water distribution system 15 collects and is then pumped back to the water distribution system with water pump 23.

[0036] The reaction unit 3 includes plenum 11, which is laterally adjacent to the flanking humidifiers 5, over top of which is situated a section of film fill 37. A reaction fluid distribution system 25 is located above the section of film fill 37 for distributing a reaction fluid over the fill. While various pollutants may be removed from the air using appropriate reaction fluids according to known reactions, the invention will be described with reference to non-limiting example of removing of carbon dioxide from air using sodium or potassium hydroxide. The reaction fluid distribution system 25 includes header 31 and spray nozzles 33. The reaction fluid distribution system is fed by riser 27 from feed pipe 29 (See, e.g., FIG. 4).

[0037] The fan 7 draws air through the splash fill 13 in the humidifier sections 5 as the fill is wetted by the water distribution system 15; the air drawn by the fan then passes into the plenum 11 and up through the film fill 37 that is wetted by the reaction fluid distribution system 25 and out the top of the device. When the ambient air, humidified by the humidifiers 5, contacts the reaction fluid in the film fill section of the reaction unit 3, a chemical reaction causes a mass transfer of carbon dioxide in the air to bond with the potassium or sodium to form potassium carbonate or sodium carbonate and water. The resulting potassium carbonate or sodium carbonate and unreacted reaction fluid fall into the central basin 35 for further processing or disposal. Optional drift eliminators 39 may be situated between the splash fill 13 of the humidifiers 5 and the plenum 11 and/or above the reaction fluid distribution system 25.

[0038] The device shown in FIGS. 1 and 2 is an individual module or “cell” containing a single reaction unit, which may be used standalone, or together with a plurality of other cells, as shown in FIGS. 3 through 5. According to the embodiment of FIGS. 3 through 5, the water basins 21 and the reaction fluid basin 35 each run the length of a plurality of cells. Additionally, a water supply pipe 43 runs along the top of each humidifier section providing water to the water distribution systems 15 of each cell. A reaction fluid supply pipe 29 is buried beneath the longitudinal axis of the center basin 35, and feeds reaction fluid to the reaction fluid distribution system 25 via riser 27. As shown in FIG. 5, the fan 7 is enclosed by a fan cylinder or shroud 47, the fan deck 49 is enclosed with a safety railing 51; the outside of the unit is clad in corrugated casing 51, and a stairway 55 may be provided to permit service access to the top of the unit.

[0039] FIG. 6 shows an embodiment of the invention for use in locations where humidifiers are not necessary due to the normal humidity of the ambient air or where humidifiers are not economical due to a lack of water. According to this embodiment, no humidifiers are provided. The fan 7 draws ambient air directly into the plenum 11 of the reaction unit 3 up through a section of film fill 37 and out the top of the unit. Reaction fluid distribution system 25 distributes the reaction fluid over the fill 37 and the resulting carbonate and unreacted reaction fluid and water fall into the reaction fluid basin 35. Louvers 9 are provided at air inlets 4 to the plenum 11, and cladding or other sheathing is provided around the exterior of the fill section and the fluid distribution section.