Electrochemical cells utilizing taylor vortex flows

1. An electrochemical cell ( 12 ) used to convert chemical energy into electrical energy and containing first and second cylinder-like electrodes ( 34 , 36 ) separated by a fluid electrolyte gap (d, 40 ) between the electrodes ( 34 and 36 ), comprising:

a. means ( 34 , 36 ) for creating Taylor Vortex Flows ( 50 ) in electrolyte in the gap; and

b. means ( 50 ) for extracting unwanted contaminants ( 64 ) from the electrolyte.

2. An electrochemical cell ( 10 ) used for converting chemical energy into electrical energy comprising:

a. a first electrode ( 36 ) that is—

i. reactive with a first chemical entering its pores from its first surface ( 44 ) to produce a first ion at its second surface layer( 36 ′);

b. a second electrode ( 34 ) that is—

i. reactive with a second chemical entering its pores from its first surface ( 32 ) to produce a second ion at its second surface ( 34 ) having a charge different from that of the first ion, and

ii. within the first electrode ( 36 ) so that a chamber ( 40 ) is created between the second surface layers ( 36 ′ and 34 ′) of the two electrodes ( 36 and 34 );

c. a fluid electrolyte in the chamber ( 40 ); and

d. means for moving one electrode ( 36 or 34 ) with respect to the other

electrode ( 34 or 36 ) to create flows ( 50 ) in the fluid electrolyte so as to generate a voltage across the electrodes ( 36 , 34 ) that are adapted to be connected to an external electrical circuit.

3. The electrochemical cell ( 10 ) of claim 2 wherein:

Taylor Vortex Flows ( 50 ) are created in the fluid electrolyte.

4. The electrochemical cell ( 10 ) of claim 2 wherein:

Circular Couette Flows ( 58 ) are created in the fluid electrolyte.

5. The electrochemical cell ( 10 ) of claim 2 wherein:

a. the first electrode ( 36 ) is cylinder-like and its second surface layer is its inner surface layer ( 36 ′); and

b. the second electrode ( 34 ) is cylinder-like and its second surface layer is its outer surface layer ( 34 ′) that is located substantially parallel to and within the first cylinder-like electrode ( 36 ) so as to create the chamber ( 40 ) for the electrolyte between the electrodes ( 36 and 34 ).

6. The electrochemical cell ( 10 ) of claim 2 comprising in addition:

means for controlling entry of a chemical into pores of an electrode layer ( 34 ′ or 36 ′) so that reaction-time:residence-time (t a ,/t r ,) ≦1/10.

7. The electrochemical cell ( 10 ) of claim 2 wherein:

one chemical is a reductant and the other chemical is an oxidizer.

8. The electrochemical cell ( 10 ) of claim 4 wherein one of the electrodes ( 34 , 36 ):

a. a catalytic surface layer ( 34 ′, 36 ′), and

b. protuberances ( 60 ) that extend from the surface layer ( 34 ′, 36 ′) into the Circular Couette Flows ( 58 ).

9. The electrochemical cell ( 10 ) of claim 8 wherein one of the electrode catalytic surface layers ( 34 ′, 36 ′) comprises:

nanoporous metal foam( 90 ).

10. The electrochemical cell ( 10 ) of claim 9 wherein the nanoporous metal foam ( 90 ) comprises:

pores ( 92 ) surrounded by scaffold struts ( 94 ).

11. The electrochemical cell ( 10 ) of claim 10 wherein the nanoporous metal foam ( 90 ) comprises:

organic catalyst particles that decorate the scaffold struts ( 94 ).

12. The electrochemical cell ( 10 ) of claim 10 wherein the nanoporous metal foam ( 90 ) comprises:

metal catalyst particles that decorate the scaffold struts ( 94 ).

13. The electrochemical cell ( 10 ) of claim 9 wherein the metal is selected from the:

Platinum Metals Group.

14. The electrochemical cell ( 10 ) of claim 13 wherein the metal comprises:

an alloy selected from the Platinum Metals Group.

15. The electrochemical cell ( 10 ) of claim 14 wherein the alloy comprises:

platinum.

16. The electrochemical cell ( 10 ) of claim 14 wherein the alloy comprises:

ruthenium.

17. The electrochemical cell ( 10 ) of claim 5 comprising in addition:

a fuel reformer ( 14 ) located with the second electrode ( 34 ) that generates hydrogen gas, which enters into fuel cell ( 12 ) by penetrating the second electrode ( 34 ).

18. A process for operating an electrochemical cell ( 10 ) to produce electricity for transmission to an external load comprising:

a. pumping a reductant through anode electrode ( 34 ) of the cell ( 10 );

b. pumping an oxidizer through cathode electrode ( 36 ) of the cell ( 10 );

c. pumping electrolyte into electrolyte chamber ( 40 ) of the cell ( 10 ) that is located between the electrodes ( 34 and 36 ); and

d. rotating one electrode ( 34 or 36 ) with respect to the other electrode ( 36 or 34 ) at a rate sufficient to cause Taylor Vortex Flows ( 50 ) in the electrolyte chamber ( 40 ).

19. The process of claim 18 wherein:

the rotation of one electrode ( 34 or 36 ) with respect to the other electrode ( 34 or 36 ) is at a rate sufficient to cause electrolyte Circular Couette Flows in the electrolyte chamber ( 40 ).

20. The process of claim 19 wherein the reductant is:

hydrogen.

21. The process of claim 18 in which the cell ( 10 ) contains a fuel reformer chamber ( 26 ) between a fixed catalytic surface ( 18 ) and a rotating catalytic surface ( 24 ) and the process comprises an additional step of:

a. Pumping a fuel containing hydrogen atoms into the fuel reformer chamber ( 26 ); and

b. Rotating the reformer rotating catalytic surface ( 24 ) at a speed sufficient to cause—

i. fuel reformer Taylor Vortex Flows ( 28 ) in reformer chamber ( 26 ),

ii. fuel cell Taylor Vortex Flows ( 50 ) in the fuel cell electrolyte chamber ( 40 ), and

iii. H 2 from the fuel to penetrate through anode electrode ( 34 ) to creates H + ions that pass into the electrolyte chamber ( 40 ).

22. The process of claim 21 wherein:

Rotation of one electrode ( 34 or 36 ) with respect to the other electrode ( 36 or 34 ) is at a rate sufficient to cause Circular Couette Flows ( 58 ) in the electrolyte chamber ( 40 ).

23. A system for enhancing catalyzed reaction rates at porous catalytic surfaces ( 34 ′, 36 ′) of an electrochemical cell ( 10 ) used to convert chemical energy into electrical energy, the system comprising:

a. a first electrode ( 34 ) having a first porous catalytic surface layer ( 34 ′);

b. a second electrode ( 36 ) having a second porous catalytic surface layer ( 36 ′);

c. the first electrode ( 34 ) and the second electrode ( 36 ) defining an electrolyte chamber ( 40 ) between the first porous catalytic surface layer ( 34 ′) of the first electrode ( 34 ) and the second porous catalytic surface layer ( 36 ′) of the second electrode ( 36 ), the electrolyte chamber ( 40 ) including an electrolyte input tube ( 42 ) configured so that a liquid electrolyte passing through the electrolyte chamber ( 40 ) from the electrolyte input tube ( 42 ) passes adjacent the first and second electrodes ( 34 , 36 ); and,

d. the electrolyte chamber ( 40 ) being dimensioned, and at least one of the first electrode ( 34 ) or the second electrode ( 36 ) being configured to rotate relative to the other of the first electrode ( 34 ) or the second electrode ( 36 ) at a rate of rotation adequate to produce Taylor Vortex Flows ( 50 ) within the liquid electrolyte flowing from the electrolyte input tube ( 42 ) through the electrolyte chamber ( 40 ).

24. The system of claim 23 , wherein the electrochemical cell ( 10 ) comprises:

a fuel reformer ( 14 ) located within the first electrode ( 34 ) and having a fuel reformer chamber ( 26 ) on the side of the first electrode ( 34 ) that is opposite that of the electrolyte chamber ( 40 )

wherein fuel from the reformer chamber ( 26 ) penetrates the first electrode ( 34 ).

25. The system of claim 24 wherein:

the first electrode ( 34 ) is rotated a rate of rotation adequate to produce Taylor Vortex Flows ( 28 ) within the fuel reformer chamber ( 26 ).

26. The system of claim 25 wherein:

the first electrode ( 34 ) is rotated at a rate of rotation adequate to produce Circular Couette Flows ( 28 , 50 ) in the fuel reformer ( 26 ) and the fuel cell ( 12 ) electrolyte chamber ( 40 ).

27. The system of claim 23 wherein the electrodes ( 34 , 36 ) are separated by an electrolyte chamber ( 40 ) to permit one electrode ( 34 ) to rotate within the other electrode ( 36 ) and the electrolyte chamber ( 40 ) has a gap distance d, and gap length L, and further comprising:

a. means for rotating one electrode ( 36 , 34 ) with respect to the other electrode ( 34 , 36 ) at Ω radians per second;

b. means for pumping electrolyte into and out of the chamber ( 40 ) at a total volumetric exchange rate of {dot over (U)}/U where U is the volume of electrolyte in the chamber and {dot over (U)} is the volumetric rate of flow into and out of the chamber ( 40 ); and

c. means for regulating the volumetric exchange rate of axial flow and Taylor Number T c of vortex flow in the electrolyte so that—

T c =2 r 2 Ω 2 d 3 /v 2 (1+{ r 1 /r 2 })>1,715( f{R a }), and;

R c ={Ωr 1 d/v}≦ 10 4

where:

1. f{R a }=1.0+(0.297)(log 10 R a ) 4.04342 for R a ≧1.0

f{R a }=1.0 for 0≦R a ≦1.0

2. r 1 =the largest radius of the first electrode,

3. r 2 =the smallest radius of the second electrode,

4. v=kinematic viscosity of electrolyte=μ(poise)/ρ(grams/cc.),

5. R a =(dL/v)({dot over (U)}/U), and

6. {dot over (U)}/U≧0.

28. The system of claim 23 wherein the electrochemical cell ( 10 ) wherein a chemical reactant passing through the cell ( 10 ) has a reaction time (t a ) within the first or second electrode ( 36 , 34 ) and comprising in addition:

means for causing the chemical reactant to pass through a reaction zone of the first or second electrode ( 36 , 34 ) zone in a length of time (t r ) that is at least 10 times a chemical conversion reaction time (t a ) for the chemical reactant within the first or second electrode ( 36 , 34 ).

29. An electrochemical cell ( 10 ) used to convert chemical energy into electrical energy and comprising:

a. a first surface ( 34 ′) that contains a catalyst,

b. a second surface,

c. a fluid between the surfaces ( 34 ′ 36 ′), and

d. means ( 34 , 36 ) for generating Taylor Vortex Flows ( 50 ) in

the fluid that is enveloped by a laminar shear boundary ( 58 ) adjacent to one of the surfaces ( 34 ′, 36 ′).

30. An electrochemical cell ( 12 ) used to convert chemical energy into electrical energy and comprising:

a. a cathode electrode ( 36 , 36 ′),

b. an anode electrode ( 34 , 34 ′),

c. a fluid electrolyte between the electrodes ( 36 , 36 ′ 34 , 34 ′), and

d. means ( 34 , 36 ) for generating a Taylor Vortex Flows ( 50 ) in the electrolyte that is enveloped by a laminar shear boundary ( 58 ) adjacent one of the electrodes ( 36 , 36 ′ 34 , 34 ′).

31. In an electrochemical cell ( 10 ) used to convert chemical energy into electrical energy and containing a fluid, an improvement comprising:

means ( 18 , 24 , 34 , 36 ) for creating Taylor Vortex Flows ( 28 , 50 ) in the fluid.

32. In the electrochemical cell ( 10 ) of claim 31 , a further improvement comprising:

means ( 18 , 24 , 34 , 36 ) for creating Circular Couette Flows ( 28 , 50 ) in the fluid.

33. In the electrochemical cell ( 10 ) of claim 32 , a further improvement comprising:

one cylinder-like electrode ( 34 ) rotating relative to and separated by a fluid chamber ( 40 ) from another cylinder-like electrode ( 36 ).

34. In the electrochemical cell ( 10 ) of claim 33 , a further improvement comprising:

a fluid that is an electrolyte.

35. In the electrochemical cell ( 10 ) of claim 33 , a further improvement comprising:

protuberances ( 60 ) that extend from a surface layer ( 34 ′, 36 ′) of an electrode ( 34 , 36 ) into the Circular Couette Flows ( 58 ).

36. In the electrochemical cell ( 10 ) of claim 31 in which the means ( 34 , 36 ) for creating Taylor Vortex Flows ( 50 ) includes a first cylindrical-like electrode ( 36 ) enclosing a second cylindrical-like electrode ( 34 ) separated from the first by an electrolyte chamber ( 40 ) of gap distance d and length L and means for rotating one electrode with respect to the other at Ω radians per second, the improvement further comprising:

a. means for pumping electrolyte into and out of the chamber ( 40 ) at a total volumetric exchange rate of {dot over (U)}/U where U is the volume of electrolyte in the chamber and {dot over (U)} is the volumetric rate of flow into and out of the chamber; and

b. means for regulating the volumetric exchange rate of axial flow and Taylor Number T c , of vortex flow ( 50 ) in the electrolyte so that—

i. T c =2r 2 Ω 2 d 3 /v 2 (1+{r 1 /r 2 })>1,715(f{R a }), and;

ii. R c ={Ωr 1 d/v}≦10 4

where:

1. f{R a }=1.0+(0.297)(log 10 R a ) 4.04342 for R a ≧1.0

f{R a }=1.0 for 0≦R a ≦1.0,

2. r 1 =radius of the first electrode ( 36 ),

3. r 2 =radius of the second electrode ( 34 ),

4. d=r 1 −r 2 ,

5. v=kinematic viscosity of electrolyte=μ(poise)/ρ(grams/cc.),

6. R a =(dL/v)({dot over (U)}/U), and

7. {dot over (U)}/U≧0.

37. In the electrochemical cell ( 12 ) of claim 36 wherein RPM =30 Ω/π, coordinates of d and RPM are within a Zone of Operable Parameters ( 70 ).

38. In the electrochemical cell ( 12 ) of claim 33 in which the improvement further comprises:

a. the first electrode ( 36 ) is reactive with a first chemical entering its pores from its first surface ( 44 ) to produce a first ion at its second surface layer ( 36 ′); and

b. the second electrode ( 34 ) is reactive with a second chemical entering its pores from its first surface ( 32 ) to produce a second ion at its second surface layer ( 34 ′) having a charge different from that of the first ion.

39. In the electrochemical cell ( 12 ) of claim 38 , the improvement further comprises:

means for controlling entry of a chemical into pores of an electrode surface layer ( 34 ′ or 36 ′) so that reaction-time:residence-time (t a /t r ,) <1/10.