Abstract:
A method of producing active ingredients of the sodium initiator and calcium moderator of a consumable electrode as a flocculant mixture in a single process operation extending from the point of their reduction during electrolysis to their molten state and subsequent atomization and mixture with talc and depolarizer agents and their application in electrode construction. The consumable electrode is used in the electrolytic gas generator reaction chamber of a second-generation fuel cell.

Description:
CROSS REFERENCES  
       [0001]    The present invention relates to my copending application Ser. No. 10/072,166 placed on file Feb. 11, 2002. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    A sodium-calcium mixture is produced as a micron size flocculant by the atomization of the molten metals produced at the cathode of an electrolysis bath. In its flocculant form the sodium-calcium mixture comprises the active ingredients of a consumable electrode used in hydrolysis within an electrolytic generator described in my copending patent of Ref.  1 . The sodium component of the mixture is termed the initiator because it reacts exothermally during hydrolysis liberating hydrogen and generating sufficient heat at the intimate contacting surface interface with the calcium metal, termed the moderator causing it to likewise hydrolize and produce hydrogen.  
           [0003]    Two equivalent weights of the sodium initiator are required to produce hydrogen in its diatomic molecular form with the generation of 2 electrons. 
           2Na+2H 2 O→2NaOH+H 2 ↑+heat+2 electrons 
           [0004]    Therefore one equivalent weight of sodium initiator produces 1 electron and a positively charged proton. The charged proton attaches to a water molecule to form a hydronium molecule (H 3 O). The hydronium molecules are discharged at the cathode releasing the hydrogen protons. Each pair of protons that are discharged at the cathode are joined together by sharing an electron to form a diatomic molecule of gaseous hydrogen H 2 ↑.  
           [0005]    The calcium metal moderator within the atomized flocculant mixture reacts with water to produce hydrogen but with greater difficulty requiring the application of heat. The necessary heat is supplied by the exothermic reaction of the sodium initiator which is in intimate contact with the calcium during hydrolysis. 
           Ca+2H 2 O+initiator heat→Ca(OH) 2 +H 2 ↑+2 electrons 
           [0006]    In this latter instance 1 equivalent weight of the calcium moderator produces 2 electrons, thus doubling the electron discharge to the electrolyte solution surrounding the cathode.  
           [0007]    Because the process of electrolysis is reversible in hydrolysis, a 50/50 mixture of initiator and moderator produces at the cathode and anode of an electrolytic generator of the general type described in Ref.  1 , the sum of their fractional electrochemical equivalents, which in this instance is 567.7 amp-hours per pound of sodium-calcium flocculant within the consumable electrode.  
           [0008]    The melting point of sodium chloride is 804° C. (1479° F.) but when calcium chloride is added to the electrolysis bath the melting point is lowered to approximately 600° C. (1112° F.). This significantly reduces the costs of the reduction of the metal and extends the life of the atomization nozzle in the flocculation process when operating below 700° C. (1292° F.). The sodium-calcium mixture of the molten metal are the same as those active ingredients of Ref  1 , but in the latter application their formulation is by dispersion in a heavy mineral oil or silica based oil at room temperature. In the present invention the mixing of the sodium-calcium mixture is carried out in the molten state. In the process, the beginning charge within the cell bath is typically 58% calcium chloride and 42% sodium chloride by weight. At the elevated temperature of 600° C. the chlorine of each component is driven off and the calcium metal becomes soluble in the molten sodium metal as a mixture deposited at the cathode. The molten mixture is decanted into a heated processing chamber where it is forced under pressure through an atomizing nozzle orifice exiting as a thin stream that is broken up, and cooled below its freezing point, by a jet of compressed inert gas (nitrogen) into a micron size flocculant. The particulate size of the flocculant mixture depends upon the atomizing temperature and impinging angle and jet pressure.  
           [0009]    In Ref.  1  silica powder and diatomaceous earth as well as magnesium powders are separately added in measured quantities to an alkali metal dispersion as drying agents and to also promote capillary action and surface adsorption in the migration of water into the electrode when emersed in the electrolyte. In the present invention the silica and magnesium are combined in mineral complex form as dehydrated talc which is mixed with the sodium-calcium flocculant in the presence of a depolorization agent. The capillary wicking action in the present invention is enhanced by enclosing the active ingredients of the initiator and moderator within a fibrous paper membrane. When the electrode is not to be used in a single continuous operation, but in an interrupted fashion, the paper cylinder is flattened by calendering and segmented, and separately sealed as discreet quantum&#39;s of stored energy placed in separate compartment cells configured within the lower carrier insulation and sealed by an over-lying aluminized conductor tape. Segmenting the tape in this manner prevents capillary migration of water into the unused portion of the tape during periods of inactivity or storage.  
           [0010]    In the larger designs where current flow and operating temperatures are higher aluminium wire is embedded along the tape edge to assure tensile integrity and electrical continuity.  
         SUMMARY OF THE INVENTION  
         [0011]    The invention is a consumable electrode comprising an alkali metal initiator and an alkaline earth moderator each of which when hydrolyzed reverses the electronic process of their cathodic reactions during their formative period of electrolysis to release within an electrolytic generator, as described in Ref.  1 , an electrochemical equivalent current of equal quantity.  
           [0012]    The primary objective of the invention is to provide a method by which the consumable electrode comprising a sodium initiator and calcium moderator which are produced simultaneously as a flocculant mixture in a single process operation at the electrolysis bath station eliminating the procedural operating steps of calcium freezing point separation and sodium decanting and filtering processes and their subsequent particulate recombination at room temperatures during the electrode manufacture as described in my co-pending patent of Ref.  1 . Producing the sodium-calcium flocculant mixture at the point of their joint electrolysis significantly lowers the production costs of the electrode.  
           [0013]    It is yet another object of the invention to eliminate the mineral oil or silica based dispersion medium of Ref.  1  to lower the carbon content of the component elements comprising the formulation of the consumable electrode and thus decrease the level of contaminant carbonate material found in the generator electrolyte and the amount of carbon dioxide in the cathode and anode liberated hydrogen and oxygen gas streams respectively which poison the down-stream fuel cell operating in tandem with the generator.  
           [0014]    And still it is yet another object of the invention to bring the initiator and moderator into intimate contact in a manner that produces an increased surface interface between these two components such that the hydrolysis and subsequent oxidation of the calcium component at the induced initiator higher exothermic temperature is more easily and efficiently attained facilitating the electron release of the calcium and increasing the electrochemical equivalent generating capacity of the electrode.  
           [0015]    Another object of the invention is to provide alternative system wicking and thermal ballast material in the form of fibrous roving and paper and mineral talc compositions respectively which may replace or supplement and otherwise enhance electrolyte capillary action and thus improve the uniformity of electrolyte diffusion within the electrode.  
           [0016]    Still another object of the invention is to improve the tensile integrity of the cathode carrier insulation and increase the assurance of its electrical conductance at higher electrode current flow and operating temperature by embedding metal wire within the said carrier insulation. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]    Drawings are presented which show the method of manufacture of the active ingredients of the consumable electrode and the manner of their assembly between the electrode carrier insulation and conductor cover tape.  
         [0018]    [0018]FIG. 1 Is a diagrammatic cross-section of an electrolysis bath connected in series flow with an atomizing chamber for the production of a sodium-calcium flocculent.  
         [0019]    [0019]FIG. 2 Is a drawing of a length of carrier insulation and aluminized conductor tape showing the general features of their construction and the intervening segmented active ingredients of the sodium initiator and calcium moderator calendered upon a paper or glass roving wick material creating a wicking element.  
         [0020]    [0020]FIG. 3 Is a drawing of a cross-section of the consumable electrode.  
         [0021]    [0021]FIG. 4 is a cross-section of the consumable electrode showing an imbedded wire conductor at each edge. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0022]    The invention is a consumable cathode electrode that is to be used for the splitting of hydrogen protons from water with the simultaneous generation of a corresponding electrochemical equivalent current flow within a caustic electrolyte solution of a sodium hydrogen generator.  
         [0023]    [0023]FIG. 1 is a flow schematic, shown principally in cross-section, of an electrolysis bath  1  in series circuit with a heated process chamber  2 , a pressure pump  3 , an atomizing nozzle  4 , an inert gas blast nozzle  5 , an atomization chamber  6 , a sodium-calcium flocculant product bin  7 , holding the flocculant  8  and the screw conveyer  9  that moves the flocculent to a rotating tumbler where it is thoroughly mixed with a dehydrated talc and trace amounts of a depolarizer agent. The electrolysis bath  1  of FIG. 1 is comprised of a charging gate  10  for charging the bath with 58% by weight of calcium chloride and 42% sodium chloride comprising the charge mix  11 . The temperature of the sodium chloride and calcium chloride salt mix  11  are raised to the melting point of the mixture (600° C.) by passing current through the charge mix  11  between the graphite anode  12  and iron ring cathode  13  in which the said anode  12  and cathode  13  are separated by a circular iron screen  14  which permits migration of ions but prevents direct contact of the reduced metal components of mix  11  that are gathered about cathode  13 , with the chlorine gas produced at the anode. The chlorine gas is directed upward from the molten mix  11  under hood  15  and exits from bath  1  through conduit  16  to storage for recombination and future reuse.  
         [0024]    At the elevated bath  1  temperature the calcium metal formed at the cathode  13  is soluble with the sodium metal at said cathode  13  and the molten sodium-calcium mixture exits bath  1  through conduit  17  and flows into heated process chamber  2  where it is admitted into pressure pump  3  through valve  18 . The said pressure pump  3  forces the molten mixture through atomizing nozzle  4  which comprises a tungsten tip for longer wear. The molten sodium-calcium mixture is forced at high velocity from atomizing nozzle  4  at high velocity into a atomizing chamber  6  where it passes through a blast of high pressure nitrogen gas, or other inert gases, from blast nozzle  5  and is torn apart and instantaneously solidified as a mixture of micron size coherent mass of sodium-calcium flocculant  8  which is directed into product bin  7 . The flocculant  8  is transferred from the said product bin  7  by screw conveyer  9  to a revolving tumbler chamber where it is thoroughly mixed with a dehydrated talc and with trace amounts of a depolarizer agent, such as oleic acid. The finished formulation of flocculant  8 , talc, and depolarizer, hereinafter called the consumable cathode active ingredients, are then transferred by screw conveyer to a product manufacturing bin for insertion into the said consumable electrode.  
         [0025]    The proposed process of maintaining the calcium dissolved in the molten sodium instead of freezing it out and filtering off as the case of the generally followed process of sodium production, and by atomizing the molten mixture into flocculant  8  in a single heating and in a singular flowing operation at the electrolysis bath station greatly accelerates the production of the active ingredients and reduces the cost of the manufacture and formulation of the active ingredients of the consumable electrode.  
         [0026]    Turning now to FIG. 2 of the drawings. FIG. 2 shows the three major structural elements of the consumable electrode comprising aluminized conductor tape  19 , segmented fuel wicking element  20  and configured carrier insulation  21 .  
         [0027]    The said aluminized conductor tape has two longitudinal rib protrusions  22  at each edge. The said protrusions fit within and interlock with grooves  23  running longitudinally at each edge of the said carrier insulation  21 . The said segmented fuel wicking elements  20  fit within the compartments  24  of the said carrier insulation  21 .  
         [0028]    The segmented wicking elements  20  are comprised of the structural elements of glass roving or fibrous paper in which the active ingredients within the sodium - calcium flocculant  8  and the dehydrated talc and depolarizer additives have been calendered into their surfaces to the required thickness of compartments  24  of the carrier insulation  21 . When the conductor tape  19  and carrier insulation  21  are brought together enclosing the wicking elements  20  in their respective compartments the said conductor tape  19  and said carrier insulation  21  are heat sealed cross-wise on each end of the compartments  24  at seal point  25  indicated by the broken line.  
         [0029]    [0029]FIG. 3 is an assembled cross-section of the consumable electrode elements shown in FIG. 2. In FIG. 3 the conductor tape  19  is laser sealed to carrier insulation  21  at their interface  27 , or they may be sealed by other means.  
         [0030]    [0030]FIG. 4 is an assembled cross-section of the consumable electrode having the same elements of the cross-section of FIG. 3 and include the additional feature of a conducting wire  28  imbeded in grove  23  of carrier insulation  21 . The wire  28  increases the tape tensile integrity and assurance of good electrical conductivity at generator higher operating temperatures.