Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
  • H01M8/04276—Arrangements for managing the electrolyte stream, e.g. heat exchange
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/08—Fuel cells with aqueous electrolytes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/14—Fuel cells with fused electrolytes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
  • H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
  • H01M8/04089—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants
  • H01M8/04097—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants with recycling of the reactants
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/22—Fuel cells in which the fuel is based on materials comprising carbon or oxygen or hydrogen and other elements; Fuel cells in which the fuel is based on materials comprising only elements other than carbon, oxygen or hydrogen
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/30—Hydrogen technology
  • Y02E60/50—Fuel cells

Definitions

• This invention relates to electrical fuel cells.
• US Patent 5,569,370 and Australian Patent No. 654774 concern a metal recovery process which involve a concept of connecting the solutions in an anode section and in a cathode section with a set of independent electrodes immersed in the anode and in the cathode sections and joined externally by an electrical conductor.
• This process avoids the use of a diaphragm between the anode and cathode sections which results in faster reaction rates favourable for commercial applications.
• a chemical reaction occurs in the solution when a potential is impressed between the anode and the cathode.
• a fuel cell is the opposite of an electrochemical cell; chemical reactions occur in the solution in the fuel cell and the electrons participating in the reactions are collected to form an electrical current.
• One early form of the fuel cell is a diaphragm separating the anode and cathode electrodes which are immersed in the electrolyte.
• Fuel such as hydrogen gas is fed into the anode section where dissolved hydrogen is adsorbed on the anode electrode forming hydrogen ions and releasing electrons in acid electrolytes as follows:
• MCFC fuel cells have the capability to accept carbon fuels but polarisation and corrosion of the nickel electrodes is a problem.
• the latest in fuel cell development is the Solid Oxide Fuel Cell or SOFC (reference: S. Baldwal and K. Folger, Ceramic International, 22, (1996) 257- 265).
• the cell operates at about 1000 C and features a Y2O3 doped Zr ⁇ 3 solid electrolyte which is an oxygen ion conductor located between the lanthanum-manganite cathode and Ni/Zr ⁇ 2-cermet anode.
• the oxygen molecule is adsorbed at the cathode and reduced to oxygen ion and the requirement for four electrons.
• the oxygen ion migrates through the electrolyte to the anode where it reacts with the fuel forming water and carbon dioxide and producing electrons.
• SOFC can handle hydrocarbon fuels but the high temperature required creates problems of stability of the materials used.
• the invention is said to reside in a fuel cell comprising a separate anode cell and a separate cathode cell, the separate anode cell including an anode tank for containing an electrolyte and having an anode electrode immersed therein, means to supply electrolyte to the anode tank and means to supply fuel to the anode tank, the separate cathode cell including a cathode tank for containing the electrolyte and having a cathode electrode immersed therein, means to supply electrolyte to the cathode tank and means to supply an oxidant to the cathode tank, means to withdraw reacted electrolyte from the anode tank and to supply it to the cathode tank, means to withdraw reacted electrolyte from the cathode tank and to supply it to the anode tank, a first electrode immersed in the electrolyte in the anode tank adjacent but not in contact with the anode electrode, a second electrode immersed in the catho
• the fuel may be selected from the group comprising hydrogen, natural and refined hydrocarbons such as methanol, ethanol and other alcohols and natural and manufactured carbohydrates.
• the oxidant may be selected from the group comprising air, oxygen, oxygen- nitrogen mixtures, oxygen-carbon dioxide mixtures and hydrogen peroxide.
• the first electrode and the second electrode together may form a common conductive wall between the anode tank and the cathode tank which completes the electrical circuit.
• first electrode and the second electrode together may be a diaphragm or membrane which forms a common conductive wall between the anode tank and the cathode tank which completes the electrical circuit.
• the anode electrode, the cathode electrode, and the first and the second electrodes may be made from a material selected from the group solid, porous, fibre, gauze, or woven cloth of metal, carbon, conducting plastics material, or a slurry comprising catalyst or fine particles coated with catalyst fluidised in the respective tanks.
• the anode electrode and the cathode electrode may be electroplated or coated with catalyst selected from platinum, nickel, cobalt, lithium, lanthanum, strontium, palladium, yttrium, or any mixture of these.
• the electrolyte may be selected from the group acidic electrolytes including sulphuric acid, phosphoric acid, methane sulphonic acid, other organic and inorganic acids, alkaline electrolytes including sodium hydroxide and potassium hydroxide, molten electrolytes including lithium-potassium carbonate and dispersions of fine solids in a liquid, the fine solids or a coating on the fine solids being a catalyst for the anode reaction or the cathode reaction.
• acidic electrolytes including sulphuric acid, phosphoric acid, methane sulphonic acid, other organic and inorganic acids
• alkaline electrolytes including sodium hydroxide and potassium hydroxide
• molten electrolytes including lithium-potassium carbonate and dispersions of fine solids in a liquid, the fine solids or a coating on the fine solids being a catalyst for the anode reaction or the cathode reaction.
• the invention may be said to reside in a fuel cell consisting of a separate anode cell and a separate cathode cell and a reaction vessel, wherein: the anode cell comprises an anode tank, the cathode cell comprises a cathode tank, the anode tank has an anode electrode immersed therein, means to supply electrolyte to the anode tank from the cathode tank or from the reaction vessel, means to supply fuel in the form of gas, or liquid, or solid, mixed with the electrolyte, the cathode tank has a cathode electrode immersed therein, means to supply electrolyte to the cathode tank from the anode tank or from the reaction vessel, means to supply air, oxygen-nitrogen mixtures or other oxidant to the cathode tank mixed with the electrolyte, means to withdraw reacted electrolyte from the anode tank to the cathode tank or to the reaction vessel, and means to withdraw reacted electrolyte from the
• the invention may also comprise a battery of fuel cells comprising a plurality of fuel cells as described above wherein the anode electrodes and cathode electrodes are electrically connected in series or in parallel.
• the invention is said to reside in a continuous process for producing electric power and heat in a fuel cell from reacting a fuel in a anode tank and an oxidant in a cathode tank, the fuel cell having a first electrode immersed in an electrolyte in the anode tank adjacent but not in contact with an anode, a second electrode immersed in the electrolyte in the cathode tank adjacent to but not in contact with the cathode, and an external electrical connection between the first electrode and the second electrode, the process comprising the steps of; introducing the fuel with the electrolyte in the anode tank wherein a catalyst on the anode in the anode tank causes a chemical reaction or ionises the fuel which produces electrons, transferring the electrons through an external electrical circuit through an electrical load and to the cathode in the cathode tank, introducing the oxidant with the electrolyte into the cathode tank wherein a catalyst on the cathode causes a chemical reaction or
• the ions produced at the anode required for the reaction at the cathode may be delivered continuously through the electrolyte and the ions produced at the cathode required for the reaction at the anode may be delivered continuously through the electrolyte. There may be further included the step of recycling excess fuel exiting the anode tank to a feed of the anode tank.
• the anode tank and cathode tank may be heated and pressurised.
• Heat produced from the reaction may be recovered for co-generation, industrial heating and domestic heating.
• the fuel may travel co-current or counter-current to the electrolyte in the anode tank and the oxidant may travel co-current or counter-current to the electrolyte in the cathode tank.
• the first electrode and the second electrode together may form a common electrically conductive wall between the anode tank and the cathode tank and the step of completing the electronic circuit may include the step of completing the electronic circuit through the common conductive wall.
• the first electrode and the second electrode together may be a diaphragm which forms a common electrically conductive wall between the anode tank and the cathode tank and the step of completing the electronic circuit may include the step of completing the electronic circuit through the diaphragm.
• this invention is a chemico-electrical process to collect the electrical power and heat from the reaction of fuel and an oxidant.
• the process is carried out in a separate anode cell where fuel and electrolyte are introduced and a separate cathode cell where the oxidant and electrolyte is introduced.
• a complete electrical circuit is established between the anode and the cathode cells by an independent set of electrodes immersed in the anode electrolyte and in the cathode electrolyte and these independent set of electrodes are connected externally by an electrical conductor. Ion transport within the fuel cell is accomplished by circulating the fluid electrolyte containing the ions between the anode and cathode.
• FIG 1 shows a voltage time curve for a conventional prior art fuel cell
• FIG 2 shows a voltage time curve for a fuel cell according to one embodiment of the present invention
• FIG 3 shows a voltage time curve for a fuel cell according to the embodiment of FIG 2 with a load connected
• FIG 4 shows a schematic block diagram of a fuel cell according to one embodiment of the present invention
• FIG 5 shows a schematic block diagram of a fuel cell according to an alternative embodiment of the present invention
• FIG 6 shows a schematic block diagram of a fuel cell according to a further embodiment of the present invention
• FIG 7 shows a schematic block diagram of a fuel cell according to a further embodiment of the present invention.
• FIG 8 shows a schematic block diagram of a fuel cell according to a further embodiment of the present invention.
• FIG 9 shows a schematic block diagram of a fuel cell according to a further embodiment of the present invention.
• the diaphragm type cell measured about 240 mm x 60 mm x 25 mm (inside dimensions) with a polypropylene cloth diaphragm between the anode and cathode section.
• the electrodes were made of Hastelloy-C and measured 40 mm x 160 mm with 140 mm, painted with platinum black held with an organic/PTFE binder.
• the binder of the commercially purchased electrodes appear to be insufficiently cured and this may be the reason for the lower voltage attained in these experiments than might be expected for a fuel cell.
• FIG 4 is typical of a fuel cell using an acid electrolyte such as phosphoric acid.
• Figure 7 shows the application of this process where the fuel and oxidant are catalysed independently and the ions produced are reacted in a reaction vessel.
• This configuration may avoid the poisoning of the catalyst in either the anode or cathode. It may also segregate the heat produced from the process to provide convenient co-generation applications.
• the reacted electrolyte outlet 7 from the anode tank 1 is first separated from excess fuel in vacuum separator 8 and is then passed to reaction vessel 15.
• the reacted electrolyte outlet 16 from the cathode tank 1 is passed to reaction vessel 15.
• the hydrogen ions from the anode tank and the oxygen ions from the cathode tank are reacted to produce water.
• the water is removed and discarded through line 17.
• the purified electrolyte is then returned to both the anode tank through inlet 6 and the cathode tank 2 through inlet 23.
• the electrochemical reaction in the anode tank is;
• FIG 8 shows an alternative embodiment of a fuel cell .
• the fuel cell comprises an anode tank 60 and a cathode tank 61 which are joined by a common wall 62 which is a porous diaphragm or a solid conducting diaphragm.
• the cathode tank 61 there is a cathode 75 and the solution electrode is the diaphragm 62.
• the cathode tank has an electrolyte inlet 73 and oxidising gas inlet 74 and a reacted electrolyte, reaction product and excess oxidising gas outlet 76.
• the reaction product and excess oxidising gas is extracted from the reacted electrolyte in the vacuum vessel 77 with reaction product and excess oxidising gas being discarded through line 78 and the electrolyte being returned in line 79 to the to the inlet 66 of the anode tank.
• the electronic circuit passes through the anode 65, to the electrical load 79, to the cathode 75, across the cathode electrolyte to the diaphragm 62, through the external conductor connection which is in effect the thickness of the diaphragm 62 across the anode electrolyte, and to the anode 65.
• the electronic circuit passes through the anode 65, to the electrical load 79, to the cathode 75, across the cathode electrolyte to the diaphragm 62, through the external conductor connection which is in effect the thickness of the diaphragm 62 across the anode electrolyte, and to the anode 65.
• the fuel cell of this embodiment may be an acid or alkali type electrolyte cell.

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• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Sustainable Development (AREA)
• Sustainable Energy (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Fuel Cell (AREA)

Priority Applications (4)

Applications Claiming Priority (4)

Publications (1)

Family

ID=25645237

Family Applications (1)

Country Status (4)

Cited By (4)

Citations (6)

• 1997
  • 1997-08-04 GB GB9902329A patent/GB2342495B/en not_active Expired - Fee Related
  • 1997-08-04 WO PCT/AU1997/000488 patent/WO1998006145A1/en active Application Filing
  • 1997-08-04 JP JP10507392A patent/JP2000516017A/ja active Pending
  • 1997-08-04 DE DE19781911T patent/DE19781911T1/de not_active Withdrawn

Patent Citations (6)

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