Laminar scrubber apparatus for capturing carbon dioxide from air and methods of use

Abstract

The present invention is directed to methods for carbon dioxide from air, which comprises exposing solvent covered surfaces to air streams where the airflow is kept laminar, or close to the laminar regime. The invention also provides for an apparatus, which is a laminar scrubber, comprising solvent covered surfaces situated such that they can be exposed to air streams such that the airflow is kept laminar.

1 . A method for capturing carbon dioxide from air, which comprises exposing solvent covered surfaces to air streams where the air streams have a flow that is kept laminar, or close to a laminar regime.  
   
   
       2 . The method of  claim 1 , wherein the surfaces comprise smooth parallel plates.  
   
   
       3 . The method of  claim 1 , wherein the surfaces are not entirely flat, and follow straight parallel lines in the direction of the airflow.  
   
   
       4 . The method of  claim 1 , wherein the surfaces comprise corrugations, pipes, tubes, angular shapes akin to harmonica covers, or any combination thereof.  
   
   
       5 . The method of  claim 1 ,  2 ,  3  or  4 , wherein the surfaces are roughened with grooves, dimples, bumps or other small structures that are smaller than the surface spacing, and wherein the surface structures remain well within the laminar boundary of the air flow.  
   
   
       6 . The method of  claim 5 , wherein the Reynolds number of the flow around these dimples or surface structures is small, in an optimum it is between 0 and 100.  
   
   
       7 . The method of any one of claims  1 - 5 , wherein the surface is roughened through sand blasting or other similar means.  
   
   
       8 . The method of any one of claims  1 - 5 , wherein the surface is roughened through etching or other similar means.  
   
   
       9 . The method of any one of claims  1 - 8 , wherein the surfaces are on plates made from steel or other hydroxide resistant metals.  
   
   
       10 . The method of any one of claims  1 - 9 , wherein the surfaces are on plates are made from glass.  
   
   
       11 . The method of any one of claims  1 - 10 , wherein the surfaces are on plates made from plastics, including but not limited to polypropylene.  
   
   
       12 . The method of any one of claims  1 - 9 , wherein the surfaces are foils or other thin films that are held taught by wires and supported by taught wire or wire netting.  
   
   
       13 . The method of  claim 12 , wherein all but a supporting wire in the front and the back run parallel to the wind flow direction  
   
   
       14 . The method of  claim 12 , wherein the foil or film is supported on a rigid structure that could be a solid plate, a honeycomb, or lattice work that can lend structural rigidity to the films.  
   
   
       15 . The method of  claim 12 , wherein the films are made from plastic foils.  
   
   
       16 . The method of  claim 15 , wherein the plastic foil has been surface treated to increase the hydrophilicity of the surface.  
   
   
       17 . The method of any one of claims  12 - 16 , wherein the surfaces have been coated or treated to increase hydrophilicity of the plates.  
   
   
       18 . The method of any one of claims  1 - 17 , wherein the direction of the air flow is horizontal.  
   
   
       19 . The method of any one of claims  1 - 18 , wherein the surfaces—or the line of symmetry of the surfaces—is vertical.  
   
   
       20 . The method of any one of claims  1 - 18 , wherein the liquid solvent flow is at about a right angle to the airflow.  
   
   
       21 . The method of any one of claims  1 - 18 , wherein the surface spacing is from about 0.3 cm to about 3 cm.  
   
   
       22 . The method of any one of claims  1 - 18 , wherein the surface length is at about a right angle to the airflow direction, which is from about 0.30 m to about 10 m.  
   
   
       23 . The method of any one of claims  1 - 22 , wherein the airflow speed is from about 0.1 m/s to about 10 m/s.  
   
   
       24 . The method of any one of claims  1 - 23 , wherein the distance of airflow between the surfaces is from about 0.10 m to about 2 m.  
   
   
       25 . The method of any one of claims  1 - 22 , wherein liquid solvent is applied by means of spraying a flow onto the upper edge of the surface.  
   
   
       26 . The method of any one of claims  1 - 22 , wherein the solvent is applied to both sides of the plates  
   
   
       27 . The method of any one of claims  1 - 22 , wherein the solvent is applied in a pulsed manner  
   
   
       28 . The method of any one of claims  1 - 22 , wherein the liquid solvent is collected at the bottom of the surfaces or plates in a catch tray.  
   
   
       29 . The method of  claim 28 , wherein the collected fluid is immediately passed on to a recovery unit.  
   
   
       30 . The method of  claim 28 , wherein the collected fluid is recycled to the top of the scrubbing unit for additional CO 2  collection.  
   
   
       31 . An apparatus or method of any one of claims  1 - 22 , wherein the apparatus further comprises and is equipped with air flow straighteners to minimize losses from misalignment between the surfaces and the instantaneous wind field.  
   
   
       32 . An apparatus or method of any one of claims  1 - 22 , wherein the apparatus further comprises and is equipped with mechanisms that either passively or actively steer the surfaces so that they point into the wind.  
   
   
       33 . A laminar wind scrubber that utilizes pressure drops created by natural air flows comprising: 
 a. wind stagnation in front of the scrubber;    b. a pressure drop created by flows parallel to the entrance and/or exit into the scrubbers; or    c. a pressure drop created by thermal convection.    
   
   
       34 . A scrubber of  claim 33 , wherein the pressure drop is created in a cooling tower or by thermal convection along a hill side.  
   
   
       35 . The method of  claim 1 , wherein the surfaces are rotating disks where wetting is helped by the rotary motion of the disks and the air is moving at right angle to the axis.  
   
   
       36 . The method of  claim 35 , wherein the axis is approximately horizontal and the disks dip into the solvent at their rim and the circular motion promotes distribution of the fluid on the disks.  
   
   
       37 . The method of  claim 35 , wherein the liquid is sprayed onto the disk as it move by a radially aligned injector.  
   
   
       38 . The method of  claim 35 , wherein the liquid is extruded onto the disk near the axis  
   
   
       39 . The method of  claim 1 , wherein the surfaces are concentric tubes of circular or other cross-section shape with the air flowing in the direction of the tube asix.  
   
   
       40 . The method of  claim 39 , wherein the tubes rotate around the center axis.  
   
   
       41 . The method of  claim 39 , wherein the tube axis is oriented approximately vertically and solvent is applied in a manner that it flows downward on the surfaces of the tube  
   
   
       42 . The method of  claim 41 , wherein the axis is at some angle to the vertical and the solvent is inserted at a single point at the upper opening and flows downward in a spiral motion covering the entire surface.  
   
   
       43 . The method of any one of claims  1 - 42 , wherein the solvent is a hydroxide solution.  
   
   
       44 . The method of  claim 43 , wherein the hydroxide concentration is between 0.1 and 20 molar.  
   
   
       45 . The method of  claim 43 , wherein the hydroxide concentration is between 1 and 3 molar.  
   
   
       46 . The method of  claim 43 , wherein the concentration of the solution exceeds 3 molar  
   
   
       47 . The method of  claim 43 , wherein the concentration of the solution has been adjusted to minimize water losses or water gains.  
   
   
       48 . The method of  claim 43 , wherein where the concentration of the solution is allowed to adjust itself until its vapor pressure matches that of the ambient air.  
   
   
       49 . The method of  claim 43 , wherein the hydroxide is sodium hydroxide  
   
   
       50 . The method of  claim 43 , wherein where the hydroxide is potassium hydroxide  
   
   
       51 . The method of any one of claims  1 - 50 , wherein the solvent is a hydroxide solution where additives or surfactants have been added.  
   
   
       52 . The method of  claim 51 , wherein the additives or surfactants increase the reaction kinetics of CO 2  with the solution.  
   
   
       53 . The method of  claim 52 , wherein the additives reduce the water vapor pressure over the solution.  
   
   
       54 . The method of  claim 52 , wherein the additives or surfactants change the viscosity or other rheological properties of the solvent.  
   
   
       55 . The method of any one of claims  51 - 54 , wherein the additives or surfactants improve the absorption properties of the solvent to scrub gases other than CO 2  from the air.  
   
   
       56 . The method of  claim 55 , wherein additives are combined to create all or part of the properties recited in claims  52 - 55 .