WO2008044083A2 - Convertisseur électrochimique thermiquement régénéré et procédé de conversion d'énergie thermique en énergie électrique par ce convertisseur - Google Patents

Convertisseur électrochimique thermiquement régénéré et procédé de conversion d'énergie thermique en énergie électrique par ce convertisseur Download PDF

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Publication number
WO2008044083A2
WO2008044083A2 PCT/HU2007/000093 HU2007000093W WO2008044083A2 WO 2008044083 A2 WO2008044083 A2 WO 2008044083A2 HU 2007000093 W HU2007000093 W HU 2007000093W WO 2008044083 A2 WO2008044083 A2 WO 2008044083A2
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WIPO (PCT)
Prior art keywords
working medium
hydride
temperature
ancillary substance
metal
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PCT/HU2007/000093
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English (en)
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WO2008044083A3 (fr
Inventor
Attila HALÁCSY
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E Konverzió Innovációs Kft
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Publication of WO2008044083A2 publication Critical patent/WO2008044083A2/fr
Publication of WO2008044083A3 publication Critical patent/WO2008044083A3/fr

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    • 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
    • H01M8/18—Regenerative fuel cells, e.g. redox flow batteries or secondary fuel cells
    • H01M8/182—Regeneration by thermal means
    • 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

  • the present invention relates to a thermally regenerated electrochemical converter, as well as a method for converting thermal energy into electrical en- ergy by making use of said converter.
  • Thermally regenerated fuel cells and/or electrochemical converters are well-known. Processes for generating electrical energy from thermal energy by means of chemical energy are also known. Such means/systems and/or processes are disclosed e.g. in U.S. Pat. Nos. 4,818,638 and 4,692,390, respec- tively, wherein molten lithium hydride (LiH) or sodium hydride (NaH) is used as the working medium and also as the electrolyte of a thermally regenerated cell for converting thermal energy into electrical energy.
  • LiH lithium hydride
  • NaH sodium hydride
  • the metal hydride applied as the working medium is decomposed at a suitable first temperature to metal and hy- drogen in a decomposition vessel. Then hydrogen is directed to a first electrode of a conveniently constructed electrochemical cell.
  • the molten metal is simultaneously fed into a heat exchanger where it is cooled to a second temperature; said second temperature is significantly lower than said first one. At said lower second temperature, the molten metal thus cooled down is directed to a second electrode of the electrochemical cell.
  • the second electrode is physically separated from the first electrode of the cell. Outside of the cell, the electrodes of the cell are coupled via electrically conducting elements.
  • Inert hydrogen atoms fed to the first electrode of the cell transform into negatively charged hydrogen ions by receiving electrons from the first electrode, and then migrate to the second elec- trade of the cell through an electrolyte located between the electrodes.
  • the negatively charged hydrogen ions lose their charges, react with the molten metal fed to the second electrode and thereby combine into metal hydride at said lower temperature. All this means that an electric current flows within a circuit being electrically closed through the elec- trades and the electrolyte.
  • the metal hydride formed at the second electrode is then pumped back into the decomposition vessel, wherein due to the input thermal energy it decomposes again. That is, by means of decomposing the metal hydride acting as the working medium/electrolyte into components and then combining said components, the input thermal energy is converted into electrical energy with a given efficiency.
  • the value of the second temperature is chosen so as to increase the volt- age of the electrochemical cell to a value as high as possible. To this end, a decrease in second temperature is required.
  • the efficiency is basically determined by the difference of the first temperature (the so-called regeneration temperature) and the second temperature (i.e. the operation temperature of the cell) being lower than the first temperature; the greater the difference of the two values is, the larger is the power spent on cooling of the molten metal which arises as loss, that is, the lower is the efficiency of the conversion.
  • the temperature difference at issue is typically 500 to 600 degrees centigrade and 200 to 400 degrees centigrade for LiH and NaH electrolytes, respectively.
  • the second temperature cannot be decreased arbitrarily; to assure pum- pability of the working medium/electrolyte and hence sustainability of the cyclical process, the second temperature should be kept continuously above the point of solidification of the metal hydride used. Accordingly, the working medium/electrolyte of such a converting system is usually provided in the form of various eutectics, that on the one hand have a cost-increasing effect and on the other hand spoil the efficiency of the energy conversion.
  • U.S. Patent No. 5,139,895 teaches a possible further way of decreasing further said second temperature, that is the operation temperature of the cell.
  • the LiH electrolyte of the cell comprises a mixture of lithium (Li) and sodium (Na) of a given ratio.
  • the operating pressure and pressure difference being necessary for the migration of hydrogen ions within the system (i.e. for the operation of the cell) are provided on the one hand.
  • a shift of the solidification point of the electrolyte formed by the applied metal hydride mixture to lower temperatures is realized, and hence the op- eration of the cell at a higher voltage is achieved.
  • the decomposition temperature of the applied electrolyte will increase which is disadvantageous in respect of the conversion efficiency in view of the above, because of e.g. the necessity of cooling to a larger extent.
  • the beneficial effect of the usage of the Li/Na mixture on the operation temperature of the cell can be explained by the mutual dissolution of the two metals to a significant extent.
  • application of the Li/Na mixture and/or mixtures of similar type in a thermally regenerated electrochemical converter according to U.S. Patent No. 5,139,895 results in a decrease in the conversion efficiency, and hence cannot be eventually considered as advantageous.
  • an object of the present invention is to provide a thermally regenerated electrochemical converter and also a method for convert- ing thermal energy into electrical energy by means of said converter, wherein the difference between the regeneration and operation temperatures of an electrochemical cell made use of as part of the converter is significantly smaller than the same difference used in the case of traditional converters based on thermal regeneration.
  • a further object of the present invention is to develop a thermally regenerated electrochemical converter of an enhanced conversion efficiency by means of decreasing the difference of the regeneration and operation temperatures of the electrochemical cell used and also a conversion method exploiting the converter for producing electric energy.
  • a yet further object of the present invention is to ensure/facilitate an increase of the conversion efficiency of a regenerated electrochemical cell and a conversion method by suitably choosing the electrolyte/working medium of the electrochemical cell used.
  • the above specified objects are accomplished by adding a metallic ancillary substance to the metal hydride used as the working medium/electrolyte of the thermally regenerated electrochemical converter according to the present invention, wherein said ancillary substance (i) has an electro- negativity being more positive than that of the metal component of the metal hydride, (ii) does not blend or blends up to only a negligible extent with the metal component of the metal hydride at the operation temperature of the cell, and (iii) forms a hydride which is unstable at the operation temperature of the cell and decomposes at a temperature that is significantly lower than the operation tem- perature of the cell; it decomposes preferably at most at 250 degrees centigrade, more preferably at most at 200 degrees centigrade.
  • LiH As the electrolyte, preferentially LiH, NaH, magnesium hydride (MgH 2 ) or calcium hydride (CaH 2 ) is used in the thermally regenerated electrochemical converter according to the invention. Amongst these, LiH is the most preferred.
  • metallic ancillary substance preferably potassium (K), rubidium (Rb), cesium (Cs) or a blend of arbitrary ratio thereof is used in the thermally regenerated electrochemical converter according to the invention.
  • K potassium
  • Rb rubidium
  • Cs cesium
  • An application of the metals enlisted here in combination with LiH electrolyte is extremely preferred, as lithium hardly blends with these metals and can easily be separated/purified from them due to its high boiling point (which is about 1330 degrees centigrade).
  • the difference between the regeneration and the operation temperatures — O ⁇ of the electrochemical cell used as part of the thermally regenerated electrochemical converter according to the invention also decreases significantly, which results in an increase in the conversion efficiency due to the decrease in the cooling losses.
  • the catalytic effect is exerted by the appropriate ancillary substance through modifying the mobility of negatively charged hydrogen ions (H " -ions, from now on) in the molten metal hydride.
  • H " -ions negatively charged hydrogen ions
  • LiH is a stable non- decomposing compound at its melting point (688 degrees centigrade) under standard pressure (1 atmosphere). If, however, potassium is added to the LiH under standard pressure and then is heated together with it, a portion of the hydrogen content of the LiH (about a half of it) can be released at the temperature of 688 degrees centigrade (that is, at the melting point of the LiH), as is proven by the experiments performed in this respect.
  • LiH + Me Li + Me + 1 / 2 H 2 , wherein, according to our studies, Me stands for one of K, R, Cs or any blends thereof.
  • the released hydrogen (H 2 ) can be separated from the vapour of the an- ciliary substance added to the metal hydride by means of hydrogen permeable membranes made of metals constituting the iron-group of the periodic table of the chemical elements (preferably of e.g. nickel). Said separation is of fundamental importance when making use of a blend of said metal hydride/ancillary substance as the electrolyte of the electrochemical cell. In lack of separation, the ancillary substance would accumulate within the electrochemical cell and prohibit sooner or later the operation of the cell. The separation is based on the property that the above listed metallic ancillary substances cannot be alloyed with metals from the iron-group at all and/or the vapours thereof cannot diffuse through membranes made of such metals.
  • the separated hydrogen can then be directed to an electrode of an electrochemical cell that forms part of a converter according to the invention.
  • Lithium can also be separated from the metallic ancillary substances by suitable additional pieces of equipment. Lithium obtained in this way can be directed to the other electrode of the cell.
  • the sepa- rated metallic ancillary substance can be used for decomposing further amounts of lithium hydride.
  • the difference between the regeneration and the operation temperatures of the cell can be decreased to a very small value by adding the ancillary substance, cooling is required barely or none at all.
  • a recuperation of a certain portion of the electric energy obtained by conversion is required merely to operate pumps as well as to cover natural losses of heat. Consequently, the efficiency of the conversion method according to the invention is significantly higher than that of known thermally regenerated cells or other known thermoelectric processes.
  • FIG. 1 is a schematic skeleton diagram of a possible exemplary embodiment of an energy conversion system based on a thermally regenerated electrochemi- cal converter in accordance with the invention
  • FIG. 2 is a sectional view of a possible exemplary embodiment of the energy conversion system according to the invention in the uncharged state, that is, without a working medium/electrolyte;
  • FIG. 3 shows the energy conversion system of Figure 2 in its charged opera- tion state
  • - Figure 4 illustrates the phase diagram of a potassium/lithium (K/Li) system which shows that molten metallic potassium and lithium mutually blend only at very high temperatures (i.e. at least at or above about 1500 degrees centigrade); and - Figure 5 is a plot of the hydrogen pressure (given in units of Torr's) within the closed volume portion above Li as a function of the dissolved/retained hydrogen content for various temperatures.
  • K/Li potassium/lithium
  • the thermally regenerated electrochemical converter according to the invention and the conversion method achieved on the basis thereof will be discussed for an energy conversion system that makes use of lithium hydride as the electrolyte/working medium and potassium as ancillary substance, with no limitation on the scope of claims sought.
  • the converter to be detailed can also be made use of other metal hydrides and/or vari- ous ancillary substances; the modifications needed therefor are apparent to a person skilled in the relevant art, and hence, are not discussed here in more detail.
  • the energy conversion system based on a ther- mally regenerated electrochemical converter according to the invention converts the input thermal energy through given steps into electrical energy. Any process can serve as a source of thermal energy. In this respect, processes leading to a release of extremely large amounts of energy, e.g. heat producing processes concomitant with various nuclear reactions (nuclear fission, nuclear fusion, spal- lation, transmutation, etc.) are highly preferred. It is also clear from Figure 1 that, in the exemplary embodiment of the energy conversion system to be discussed here, said steps take place basically in five sub-units connected to each other by means of suitable tubings, as well as valves and pumps installed into the tubings.
  • an embodiment of the energy conversion system based on a converter according to the invention is comprised of a sub-unit provided as the combination of a recovery unit 2 that is equipped with a heat exchanger and a melt separator 5; a vacuum distiller 19; a galvanic cell 12 for producing electric currents; a gas separator 18; a heat pump 28; as well as pressure tubes (illustrated only schematically in Figure 1) providing connections of said units with each other, and valves and pumps inserted into the tubes at the required locations.
  • the recovery unit 2 of the energy conversion system 1 is provided in the form of a closed vessel with an inlet 51 being in fluid communication with a return tube 9 being recirculated from the galvanic cell 12, an outlet 7 and a recirculating means 6.
  • the outlet 7 is in fluid communication with an inlet 52 of the melt sepa- rator 5, said inlet 52 being formed preferably in the upper region of the melt separator 5.
  • the recirculating means 6 is in fluid communication with an outlet 53 of the melt separator 5, said outlet 53 locating preferably in the lower region of the melt separator 5.
  • a controlled pump 31 is arranged for transporting the melt from the melt separator 5 to the recovery unit 2.
  • a heat exchanger 3 is arranged, said heat exchanger 3 having a gas inlet 24 at one end thereof and an other end which opens into a return tube 55 that exits from the in- ner volume of the recovery unit 2 through the wall thereof.
  • the heat exchanger 3 has got an outer surface 23 spreading within the inner volume of the recovery unit 2.
  • a gas off-take line 39 falls into the heat exchanger 3 at a location situated between the two ends of the heat exchanger 3 and preferably closer to the end which empties into the return tube 55.
  • the other end of the gas off-take line 39, that also exits from the vessel of the recovery unit 2 is connected to an inlet 61 of the gas separator 18.
  • the heat exchanger 3 is mounted into the inner volume of the recovery unit 2 in such a way that a significant portion of its outer surface 23 locate in the vicinity of the inlet 51.
  • the points where the gas off-take line 39 and the return tube 55 exit from the recovery unit 2 are sealed hermetically.
  • the end of the return tube 55 being within the inner volume of the recovery unit 2 is equipped with a controlled melt pump 4 for transporting the melt.
  • the gas separator 18 is formed as a closed and hermetically sealed ves- sel provided with the inlet 61 , as well as a first outlet 62 and a second outlet 63.
  • a hydrogen permeable membrane 25 is arranged that divides the inner volume of the gas separator 18 into a first region 66 and a second region 67 being separated from one another.
  • the regions 66, 67 are preferably equal in size, although this is not necessary.
  • the membrane 25 of po- rous structure is made of a material (for example of nickel) which is capable of transmitting exclusively gaseous hydrogen (H 2 ) from one side thereof to another.
  • the membrane 25 is arranged within the gas separator 18 in such a way that the inlet 61 and the second outlet 63 open into one and the same of the regions 66, 67 defined by the membrane 25, while the first outlet 62 opens into the remaining other region.
  • a controlled gas pump 30 is installed into the gas off-take line 39 in the vicinity of the inlet 61 for transporting gaseous substance.
  • the return tube 55 exiting the recovery unit 2 is connected to the second outlet 63 of the gas separator 18.
  • the vacuum distiller 19 is formed as a closed and hermetically sealed vessel made of a pressure-tight material and provided with an inlet 71 , a first outlet 72, a second outlet 73 and a third outlet 74.
  • the inlet 71 is preferably in fluid communication with an outlet 54 formed in the upper region of the melt separator 5.
  • the first 72 outlet of the vacuum distiller 19 is connected via a suitable tubing (not referred to in the drawings) into a section of the return tube 55 located outside of the recovery unit 2, while the third outlet 74 of the vacuum distiller 19 is connected via a suitable tubing (not referred to either) into the return tube 9 being recirculated from the galvanic cell 12.
  • a controlled one-way transfer valve 32 is installed in between the outlet 54 of the melt separator 5 and the inlet 71 of the vacuum distiller 19, a controlled one-way transfer valve 32 is installed.
  • the opening/closing of the third outlet 74 of the vacuum distiller 19 is performed by a controlled return valve 33 arranged in the outlet 74.
  • a control of the opening/closing of the first outlet 72 of the vacuum distiller 19 is accomplished by a gas pump 20 for transporting gaseous substance from the vacuum distiller 19, said gas pump 20 being inserted into a tubing section that connects the outlet 72 into the return tube 55.
  • the galvanic cell 12 is provided in the form of an electrochemical cell built into a hermetically closed vessel, said cell comprising a cylindrical first electrode 13 closed from the bottom and a cylindrical second electrode opened from the bottom, wherein said first and second electrodes 13, 14 are apart from one another and arranged within the inner volume of said electrochemical cell.
  • the first and second electrodes 13, 14 can also be prepared with a shape differing from the cylindrical one.
  • the first electrode 13 is preferably a hy- drogen gas membrane, while the second electrode is provided by a lithium electrode.
  • the electrode 14 possesses first and second surfaces 41 , 42, respective chemical reactions take place over these surfaces 41 , 42.
  • the electrode 14 is preferably located within a volume portion that is surrounded by the electrode 13 and closed by the vessel of the galvanic cell 12 from the open direction (that is, from the above).
  • the region contained within the electrode 13 is less than the volume of the vessel, preferentially to such an extent that surfaces 41 , 42 of suitable size be available for the taking place of the chemical reactions.
  • an electrolyte preferably molten Nth- ium
  • the metal hydride applied in the energy conversion system 1 preferably molten lithium hydride
  • the electrode 13 is preferably provided with a spillway 26 in its upper region, the function of which will be- come apparent on the basis of a detailed discussion of the operation of the energy conversion system 1.
  • the vessel containing the electrochemical cell is provided with an outlet
  • the outlet 81 is located preferably in the lower region of the vessel, more preferably at the bottom thereof, and is con- nected to the inlet 51 of the recovery unit 2 via the return tube 9.
  • the gas inlet is located preferably in the lower region of the vessel, more preferably at the bottom thereof, and is con- nected to the inlet 51 of the recovery unit 2 via the return tube 9.
  • a controlled melt pump 36 is installed into the feed tubing 16. Furthermore, a controlled return pump 33' is arranged in the outlet 81.
  • the electrodes 13, 14 are mounted into the vessel of the galvanic cell 12 by means of electrically insulating members 27.
  • the electrodes 13 and 14 are connected electrically to a positive electrode 34 and a negative electrode 35, respectively, which electrodes 34, 35 are both arranged outside the galvanic cell 12.
  • Electrical energy produced from thermal energy fed into the recovery unit 2 during operation of the energy conversion system 1 appears as a potential difference between the positive and negative electrodes 34, 35; when electrically closing the two electrodes 34, 35 outside the energy conversion system 1 , as a consequence of an electrical closing through the galvanic cell 12 a direct current will flow in the closed circuit due to said potential difference, which current can be used arbitrarily.
  • the heat pump 28 providing a heat exchange of the feed tubing 16 and the return tube 9 and/or the media flowing therein also constitutes a part of the energy conversion system 1.
  • the energy conversion system 1 namely the region between the electrodes 13, 14 of the galvanic cell 12, the return tube 9 and the lower zone of the vacuum distiller 19 are filled up with the molten metal hydride, here with lithium hydride 45, which functions as the electrolyte of the galvanic cell 12 and, simultaneously, as the working medium of the energy conversion system 1.
  • the filling-up can be done through the galvanic cell 12 or through a filling-up opening (not shown in the drawings) formed in the energy conversion system 1 at a suitable other location.
  • the recovery unit 2 is filled up to a level which corresponds to the position of the heat exchanger 3 with the molten ancillary substance, in this embodiment with potassium 37, through a filling-up opening (not shown in the drawings either) formed in the recovery unit 2 specifically for this purpose.
  • a filling-up opening (not shown in the drawings either) formed in the recovery unit 2 specifically for this purpose.
  • respective sub-units of the energy conversion system 1 are filled up with the pure molten metallic component of the metal hydride applied.
  • metallic lithium is fed into the recovery unit 12 above the heat exchanger 3 and the potassium 37, as well as through the melt separator 5 above the lithium hydride 45 introduced into the vacuum distiller 19 earlier, and by operating the melt pump 36, through the feed tubing 16 and the feed entry 83 into the region defined by the electrode 14 of the galvanic cell 12 above the lithium hydride 45 already present in said re- gion. Due to evaporation of the media, vapours and/or blends of vapours of the media introduced into the system 1 will also appear in the energy conversion system 1. It is noted that the circulation of media present within the energy conversion system 1 that forms a closed system is achieved by means of the pumps being installed into the system 1.
  • the thermal energy to be converted into electrical energy is fed into the system 1 through the heat exchanger 3 of the recovery unit 2.
  • the source for thermal energy can be the coolant of a conventional nuclear reactor at critical state, a spallation reactor, a transmuting reactor (such as lead, bismuth, potassium or sodium) or the heat accumulator of a fusion reactor or any other source of thermal energy of high temperature.
  • a condition should be met; namely, the input of thermal energy should be performed along with a heat transfer coefficient and a temperature difference in order that the thermal energy input could exactly cover the required decomposition heat of lithium hydride 45 entering the recovery unit 2.
  • the thermal energy input should be completed so as to retain the temperature of the recovery unit 2 constant throughout the input. If the recovery unit 2 cools down, the decomposition process of lithium hydride 45 falls off and the metal hydride applied might even solidify. If, however, the rate of input of thermal energy is higher than what is considered to be optimal, the temperature within the recovery unit 2, and hence, also the temperatures of the media leaving it get increased. This, eventually, induces an increase in the temperature of the galvanic cell 12, as a result of which the voltage of the cell 12 decreases.
  • the present disadvan- tageous process can be compensated for by external cooling, however, when that is applied, a portion of the electrical energy obtained by conversion is used for the cooling, and hence, conversion efficiency of the energy conversion system 1 gets diminished.
  • Lithium hydride 45 fed into the recovery unit 2 reacts with the ancillary substance, here potassium 37, over the surface 23 of the heat exchanger 3 and during blending, and gaseous hydrogen 22 containing potassium vapour and lithium/potassium blend 38 (in the form of an emulsion) are produced along with the removal of the combination heat, as well as of the evaporation heat of the al- kali vapour.
  • the removed combination heat is covered partially by the thermal energy input coming from the outside and partially by the pressure-volume work performed within the system (by consuming a portion of the electrical energy produced by conversion).
  • the removed evaporation heat is covered on the one hand by the condensation of the alkali content of the gaseous hydrogen 22 containing potassium vapour that flows into the heat exchanger 3 through the gas inlet 24 due to the pressure conditions prevailing within the energy conversion system 1.
  • the removed evaporation heat is covered by the condensation of alkali vapour due to the compression between the melt pump 4 and the gas pump 30.
  • Potassium vapour condensing within the heat exchanger 3 flows to the melt pump 4 through a melt plug 29 of molten potassium that forms in the heat exchanger 3. Then, when molten potassium 37 overruns the melt pump 4, the potassium 37 containing no molten lithium flows back to the recovery unit 2 from here.
  • Gaseous hydrogen 22 containing potassium vapour flows from the heat exchanger 3 through the gas off-take line 39 and the gas pump 30 into the first region 66 of the gas separator 18, and then its hydrogen content leaves for the second region 67 of the gas separator 18 by diffusing through the hydrogen permeable membrane 25. In this way, the separation of the potassium vapour and the gaseous hydrogen takes place. Simultaneously, the lithium/potassium blend (emulsion) 38 exits through the outlet 7 of the recovery unit 2 into the melt separator 5.
  • the gas separator 18 attends to the separation of potassium vapour and gaseous hydrogen and/or to the continuous feeding in through a tubing 40 into the galvanic cell 12 of gaseous hydrogen 44 diffused into the region 67 through the membrane 25.
  • the increase of pressure needed for the condensation at the melt pump 4 is realized by the gas pump 30.
  • Potassium 37 separated from lithium/potassium blend 38 in this way is recycled from the melt separator 5 to the lower zone of the recovery unit 2 through the outlet 53 by the controlled pump 31 at the required flow rate.
  • Liquid lithium 46 containing a slight amount of potassium dissolved therein, as well as lithium hydride and dissolved hydrogen also present accidentally therein are allowed to exit into the vacuum distiller 19 through the outlet 54 of the melt sepa- rator 5 via the transfer valve 32.
  • Lithium hydride retained incidentally in lithium 46 does not disturb the electrochemical reactions taking place between the electrodes 13, 14 within the galvanic cell 12.
  • the ancillary substance (in this case potassium) fed into the energy conversion system 1 should be separated from lithium 46 to the highest possible extent, as an incidental accumulation of the alkali metal within the galvanic cell 12 might lead to a decline of conversion efficiency, and eventually to an interrupt in the operation of the cell.
  • Lithium hydride 45 obtained by separation is discharged from the vacuum distiller 19 into the return tube 9 by means of a return valve 33; said return tube 9 recycles lithium hydride 45 to the recovery unit 2 in order that it could take part in further thermal decomposition cycles.
  • Lithium 46 purified from potassium (which, optionally, can also contain a slight amount LiH) is transferred from the vacuum distiller 19 into the galvanic cell 12 by means of the melt pump 36.
  • a portion of the thermal energy to be converted can be used to heat the vacuum distiller 19.
  • the task of the heat pump 28 is to ensure that the galvanic cell 12 constituting a part of the energy conversion system 1 based on a thermally regener- ated electrochemical converter according to the invention could operate at the least possible temperature, namely at the melting point of LiH (that is, at 688 degrees centigrade), as the electrical potential of the cell after all will be the highest under this condition.
  • the optimal operating temperature increases due to the heat released. This can be prevented by pre- cooling lithium 46 fed into the galvanic cell 12.
  • Pre-cooling involves solidification of a portion of lithium hydride 45 used as the electrolyte; the system of a two- phase solid/molten lithium hydride at issue, however, maintains the galvanic cell 12 at the melting point of lithium hydride, and hence, no external cooling is re- quired.
  • the heat pump 28 cools lithium 46 flowing therethrough towards the galvanic cell 12 in a heat exchanger 21 and transfers the heat obtained from lithium 46 in a heat exchanger 11 to lithium hydride 45 transported by the return pump 33' from the galvanic cell 12 into the recovery unit 2. In this way, the heat released in the galvanic cell 12 is partially used as a supply for the decomposition heat needed in the recovery unit 2.
  • Lithium 46 pre-cooled by the heat pump 28 is directed into the galvanic cell 12, wherein it takes part in electrochemical reactions needed for the commencement of the electrical current.
  • a proper operation of the galvanic cell 12 requires a periodical filling-up of the galvanic cell 12 with lithium.
  • Pre-cooled lithium 46 enters the galvanic cell 12 at the feed entry 83. If more than one cells are applied, the galvanic cells 12 are filled up intermittently with metallic lithium 46 and during the filling-up the gal- vanic cell 12 being just filled is switched off from the production of electricity. Thereby, grounding by molten metal of the other galvanic cells 12 connected optionally in series with the one being just filled is avoided.
  • the electrical energy produced from the input thermal energy by means of the energy conversion system 1 can be withdrawn from the system through the external electrodes 34, 35.
  • the process of Li Li + + e " takes place, which is accompanied by a loss of electron.
  • the energy conversion system 1 based on a thermally regenerated elec- trochemical cell according to the invention can be constructed and operated besides the working medium/electrolyte of LiH with further electrolytes, such as NaH, MgH 2 or CaH 2 , and besides the ancillary substance of K with Rb and/or Cs (or an arbitrary blend thereof), as it was discussed earlier. Modifications/changes of the energy conversion system 1 needed for this, however, fall within the com- mon general knowledge of a person skilled in the relevant art.

Abstract

La présente invention concerne un convertisseur électrochimique thermiquement régénéré et un procédé permettant de convertir de l'énergie thermique en énergie électrique. Le convertisseur de l'invention comprend un milieu de travail se présentant sous la forme d'un hydrure métallique, une cellule galvanique (12) comprenant une première et une seconde électrode solide espacées (13, 14) et un électrolyte agencé au moins partiellement entre ces électrodes (13, 14), cet électrolyte étant choisi de façon à sélectivement laisser passer les ions d'hydrogène de charge électrique négative et fournis par une partie du milieu de travail. Ce convertisseur comprend aussi un moyen permettant de décomposer le milieu de travail en hydrogène gazeux (17) et en un métal (46) à l'état fondu à une première température par une décomposition thermique, un moyen permettant d'alimenter l'hydrogène gazeux (17) vers la première électrode (13) et un moyen permettant d'alimenter le métal fondu (46) vers la seconde électrode (14). Ce métal fondu (46) se recombine dans le milieu de travail par une réaction avec l'hydrogène gazeux (17) au niveau de la seconde électrode (14) de la cellule galvanique (12) à une seconde température inférieure la première température, tandis que les ions d'hydrogène (17) passés de la première électrode (13) à la seconde électrode (14) induisent une différence de potentiel électrique entre ces électrodes (13, 14). Un additif est ajouté au milieu de travail, cet additif entraînant la première température nécessaire à la décomposition du milieu de travail à une température proche de la seconde nécessaire à la recombinaison qui prend place dans la cellule galvanique (12). Ce convertisseur comprend aussi un moyen permettant d'empêcher l'additif ajouté au milieu de travail d'entrer dans la cellule galvanique (12).
PCT/HU2007/000093 2006-10-11 2007-10-11 Convertisseur électrochimique thermiquement régénéré et procédé de conversion d'énergie thermique en énergie électrique par ce convertisseur WO2008044083A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
HUP0600774 2006-10-11
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023057383A1 (fr) 2021-10-07 2023-04-13 Sangle Ferriere Bruno Système de pile à combustible

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3031518A (en) * 1958-08-12 1962-04-24 Mine Safety Appliances Co Fuel cells
US3119723A (en) * 1961-10-30 1964-01-28 Carl E Crouthamel Apparatus for converting heat into electricity
DE3939852A1 (de) * 1989-12-01 1991-06-06 Flachglas Solartechnik Gmbh Brennstoffzelle
US5139895A (en) * 1991-07-19 1992-08-18 General Electric Company Hydrogen thermal electrochemical converter

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3031518A (en) * 1958-08-12 1962-04-24 Mine Safety Appliances Co Fuel cells
US3119723A (en) * 1961-10-30 1964-01-28 Carl E Crouthamel Apparatus for converting heat into electricity
DE3939852A1 (de) * 1989-12-01 1991-06-06 Flachglas Solartechnik Gmbh Brennstoffzelle
US5139895A (en) * 1991-07-19 1992-08-18 General Electric Company Hydrogen thermal electrochemical converter

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023057383A1 (fr) 2021-10-07 2023-04-13 Sangle Ferriere Bruno Système de pile à combustible
FR3128064A1 (fr) * 2021-10-07 2023-04-14 Bruno SANGLE-FERRIERE Système de pile à combustible

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WO2008044083A3 (fr) 2008-05-29

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