SE203765C1 - - Google Patents

Description

Uppfinnare: E Justi, A Winsel, G Grtineberg, H Spengler och W Vielstich Prioritet begard frdn den 1 august' 1957 (Forbundsrepubliken Tyskland) Vattensonderdelning for ,utvinning ay vate och syre utfores genom elektrolys i unipolara och bipolara celler. Fran alkalisk losning (ungefar 6-n KOH) avskiljes vid anlaggning av en likspanning vate pa katoden och syre pa anoden. Inventors: E Justi, A Winsel, G Grtineberg, H Spengler and W Vielstich Priority requested from 1 August 1957 (Federal Republic of Germany) Water subdivision for, extraction of water and oxygen is carried out by electrolysis in unipolar and bipolar cells. Alkaline solution (approximately 6-N KOH) is separated by applying a direct voltage to the cathode and oxygen to the anode.

Om man anvander tva valsade nickelplatar som elektroder, är det vid en belastning av 1000 A/m2 och en driftstemperatur •av 7580°C nodvandigt med en sonderdelningsspanning av ungefar 2,3 V. (Jamfor fig. 1.) Den teoretiska sonderdelningsspanningen utgor daremot blott 1,23 volt. Det ohmska spanningsfallet i elektrolyten samt polarisationsoch overspanningar for elektroderna hoja dock den erforderliga spanningen avsevart. If two rolled nickel plates are used as electrodes, at a load of 1000 A / m2 and an operating temperature of 7580 ° C it is necessary with a probe dividing voltage of approximately 2.3 V. (Compare Fig. 1.) The theoretical probe dividing voltage, on the other hand, is only 1.23 volts. However, the ohmic voltage drop in the electrolyte as well as the polarization and overvoltages of the electrodes increase the required voltage considerably.

For att nedbringa energiforbrukningen är det myeket onskvart att arbeta med lagre cellspanning. Salunda kan man vid Bamagelektrolysken uppbyggd enligt filterpressprincipen av ,seriekopplade, hip olara celler, nedbringa den per cell erforderliga sOnderdelningsspanningen vid en belastning av 1.000 A/m2 till ungefar 2 V (se fig. 1). Aneder och katoder fOr denna cell aro framstallda av perforerade specialstalplatar och ,anoden Or porfritt fornicklad samt katoden är utrustad med en poros skelettliknande yta. Elektrodrummen aro atskilda fran varandra genom as-be st diafragmor. To reduce energy consumption, it is very difficult to work with lower cell voltage. Thus, in the Bamage electrolyte constructed according to the filter press principle of series-connected, hip-olar cells, the required breakdown voltage per cell can be reduced at a load of 1,000 A / m2 to approximately 2 V (see Fig. 1). Anodes and cathodes for this cell are made of perforated special steel plates and, the anode is pore-free nickel plated and the cathode is equipped with a porous skeleton-like surface. The electrode drums are separated from each other by asbestos diaphragms.

Det Or Oven redan kint aft framstalla elektroder med en finfordelad s. k. uppruggad yta for vattenelektrolysror genom att man atminstone pa ytan legerar elektrodmaterialet med aluminium eller zink och utloser dessa legeringsmetaller genom behandling med al kalihydroxidlosningar. Viii de pa ytan legerade platarna blir det genom utlosning av legeringsmetallen erhallna ytskiktet under elektrolysbehandlingen 'Ater frigjord sh att Mott en uppruggning av ytan kvarbliver, som astadkomm.er en viss aktivering av elektroden. Om ph ovan angivet satt genom legering av massiva legeringskroppar av elektroden erhallas och legeringsmetallen utlosas frail denna, bildas ,elektroder sum icke Oro hallbara under elektrolysbetingelserna. It has already been possible to produce electrodes with a finely divided so-called roughened surface for water electrolysers by alloying the electrode material with aluminum or zinc at least on the surface and releasing these alloying metals by treatment with alkali hydroxide solutions. In the case of the alloys on the surface, the surface layer obtained by releasing the alloy metal during the electrolysis treatment is again released so that a roughening of the surface remains, which achieves a certain activation of the electrode. If the pH stated above is obtained by alloying solid alloy bodies of the electrode is obtained and the alloy metal is released from it, electrodes are formed which are not unsolvable under the electrolysis conditions.

Foreliggande uppfinning avser att ytterligare sanka .energiforbrukningen genom anvandning av .ett elektrodmaterial med sarskilt liten polarisation vid avskiljning av vate och syre. The present invention aims to further reduce energy consumption by using an electrode material with particularly small polarization in the separation of hydrogen and oxygen.

Det bar visat sig, att en sarskilt liten energiforbrukning i elektrolyscellerna for vattensOnderdelning av unipolar eller bipolartyp astadkommes, om man som elektrodmaterial for katoderna eller som aktiv belaggning anvander Ran:ey-nickel, ,dvs. porost nickel, som erhallits genom utlosning av en metall, som t. ex. utgores av alkali- eller jordalkalimetaller och som legerats med nickel, eller sitter Raney-nickel till katodmaterialet och om man som elektrodmaterial for anoderna eller som aktiv belaggning likasa auvander Raney-nickel, Raney-silver eller silver eller sattes dessa metaller till anodmaterialet. Elektroden bestar enligt uppfinningen av exempelvis en stalplat, som Or overdragen ph en eller pa bada sidorna med ett porost dubbelskelettskikt. It was found that a particularly small energy consumption in the electrolytic cells for water subdivision of unipolar or bipolar type is achieved if Ran: ey nickel is used as electrode material for the cathodes or as active coating, ie. porous nickel obtained by the release of a metal such as e.g. consists of alkali or alkaline earth metals and which have been alloyed with nickel, or Raney nickel is attached to the cathode material and if as an electrode material for the anodes or as active coating similar to Raney nickel, Raney silver or silver or these metals were added to the anode material. According to the invention, the electrode consists of, for example, a steel plate, which is coated on one or both sides with a porous double-skeleton layer.

Vid unipolara elektrolysceller innehaller katoden Raney-nickel som dubbelskelett, ano- Dupl. kl. 12 h: 2 2-203 76 den lika Raney-nickel eller Raney-silver eller silver som dubbelskelett, vid bipolara .elektrolysceller innehalla lampligen de bipolara elektroderna Raney-nickel som dubbelskelett och som pork bestandsdel. In the case of unipolar electrolytic cells, the cathode contains Raney nickel as a double skeleton, ano- Dupl. at 12 h: 2 2-203 76 the same Raney nickel or Raney silver or silver as double skeleton, in the case of bipolar electrolytic cells the bipolar electrodes Raney nickel contain as double skeleton and as pork component.

Ett mekaniskt sarskilt fast elektrodmaterial erhaller man genom blandning av pulverformig legering av nickel eller silver och en utlosbar metall med rent nickel- eller silverpulver, varefter man pressar, sintrar och loser ut legeringselementet. A mechanically distinct solid electrode material is obtained by mixing powdered alloy of nickel or silver and a releasable metal with pure nickel or silver powder, after which the alloying element is pressed, sintered and released.

Man erhaller salunda harigenom en av ett metallskelett med inbaddade hogporka Raney-korn besthende s. k. dubbelskelettelektrod som redan foreslagits som elektroder for bransleelement. One thus obtains a so-called double-skeleton electrode consisting of a metal skeleton with embedded hog-pork Raney grains which has already been proposed as electrodes for fuel elements.

Vid framstallning .av elektrodmaterialet anvander man lampligen .enligt tyska patentskriften 1 019 361 sadana mingder pulverfor- migoch rent metallpulver, ati forhallandet mellan Raney-legering och metallpulvret ungefar utgor 1. In the preparation of the electrode material, according to German Patent Specification 1,019,361, such mixtures of powder form and pure metal powder are suitably used, in which the ratio between Raney alloy and the metal powder is approximately 1.

Det angivna dubbelskelettmaterialet erhalles pa sa salt att man antingen blandar pulverblandningar av Raney-legeringar och inaktiva bestandsdelar, sasom nickelpulver, jarnpulver, kolpulver och darav framstaller .elektroden genom pressning och sintring, som efter aktivering genom utlosning av den inaktiva komponenten av Raney-legeringen anvandes som elektroder. Darjamte ar det ocksa mojligt ,att icke framstalla hela elektroden av delta dubbelskelettmaterial utan blott for-se ytan av en konapakt eller perforerad torr kropp darmed. Detta kan ske genom att man uppressar blandningen och darefter fastsintrar eller emellertid f8rst blott pasintrar eller paklibbar blott det inaktiva pulvret (Ni, Fe, C) och darefter inriver, inpressar eller invalsar Raney-legeringen i delta portisa skikt. The specified double skeleton material is obtained in such a salt that either powder mixtures of Raney alloys and inactive constituents are mixed, such as nickel powder, iron powder, carbon powder and the electrode is produced therefrom by pressing and sintering, which after activation by triggering the inert component of Raney as electrodes. In addition, it is also possible not to produce the entire electrode from delta double skeleton material but only to provide the surface of a cone compact or perforated dry body therewith. This can be done by squeezing the mixture and then sintering or, first, only passing or gluing only the inactive powder (Ni, Fe, C) and then tearing, pressing or rolling the Raney alloy into delta portisa layers.

Vid anvandning av Raney-silver eller silver som anod 'skiljer man dessa lampligen frail katoden genom att inskjuta daremellan ett diafragma, sora ãr bestandigt mot silverperoxid och ogenomsla.ppligt for silverjoner, t. ex. membraner av ett p-fenylen-diamin-formaldehyd-harts. Dylika membraner anvandas redan vid framstallning ,av silver-ackumulatorer, for att forhindra avskiljningen av eventuellt i losning ghende silver ph katoden. When using Raney silver or silver as the anode, these are suitably separated from the cathode by inserting a diaphragm therebetween, which is resistant to silver peroxide and impermeable to silver ions, e.g. membranes of a p-phenylene-diamine-formaldehyde resin. Such membranes are already used in the manufacture of silver accumulators in order to prevent the separation of any silver ph cathode in solution.

F8rdelarna med vattenelektrolysoren enligt uppfinningen frainga av kurvorna a—d ph fig. 1 samt de pa fig. 2 och 3, varvid elektrolyten utgjordes av 5,5-n kalilut. The advantages of the water electrolyser according to the invention derive from the curves a — d ph of Fig. 1 and those of Figs. 2 and 3, the electrolyte consisting of 5,5-n potassium hydroxide.

Fig. 1 lisar cellspanningen i volt med olika stromstyrkor i ampere/m2. Fig. 1 lists the cell voltage in volts with different currents in amperes / m2.

Harvid aterfinnes kurvorna (a) yid anvandning av en elektrolysor som innehaller tva valsade nickelplatar som elektroder; vid 'en .elektrolysor, for vilken anoder och katoder framstallts ay perforerade specialstalplatar for de enligt filterpressprincipen kopplade bipolarcellerna, varvid anoderna aro porfritt fornicklade och katoderna 18rsedda 111.ed en pork yta; yid en .elektrolyscell enligt uppfinningen, vid vilken nickeldubbelskelettelektroder anvants saval som anod som katod, vilka framstallts genom blandning av pulverformig Raney-legering ailed rent metallpulver (skelettmaterial), pressning, sintring och urlakning av Raney-legeringens legeringskomponent; vid en elektrolys5r, som her en nickeldubbelskelettelektrod som katod oeh en silverdubbelskelettelektrod som .anod, varvid ba.da elektroderna framstallts enligt det yid c) angivna sattet. Vid de .bada senare elektrolysorerna utgores elektrolyten av en ungefar 6-normal kalilut och man arbetar lampligen vid 75-80°C. Hereby the curves are found (a) by the use of an electrolyzer containing two rolled nickel plates as electrodes; in the case of an electrolyzer for which anodes and cathodes are produced on perforated special steel plates for the bipolar cells coupled according to the filter press principle, the anodes being pore-free nickel-plated and the cathodes 18sed 111 with a pork surface; in an electrolytic cell according to the invention, in which nickel double skeleton electrodes are used as anode as cathode, which are produced by mixing powdered Raney alloy ailed pure metal powder (skeletal material), pressing, sintering and leaching of the alloy component of the Raney alloy; in the case of an electrolyzer, such as a nickel double skeleton electrode as cathode and a silver double skeleton electrode as an anode, both electrodes being manufactured according to the method indicated in c). In the case of the two later electrolysers, the electrolyte consists of an approximately 6-normal potassium hydroxide solution and is operated at 75-80 ° C.

Fig. 2 visar kurvor, vilka angiva olika kurvor Over cellspanningen som funktion av stromtatheten i jamforelse med vattnets termodynamiska sonderdelningsspanning yid 100°C. Kurvorna upptogs med 5,5-n kalilut som elektrolyt vid 100°C och ett elektrodavstand d = 7 mm. Fig. 2 shows curves which indicate different curves over the cell voltage as a function of the current density in comparison with the thermodynamic probe division voltage of the water yid 100 ° C. The curves were taken up with 5,5-n potassium hydroxide as electrolyte at 100 ° C and an electrode distance d = 7 mm.

Fig. 3 vicar kurvor over syre- och vateoverspanningen pa olika elektroder gentemot en matted kalomel-elektrod som j amforelseelektrod med 5,5-normal kalilut som elektrolyt vid 100°C. Den reversibla syre- och Tatepotentialen aterfinnes amen pa diagrammet. Fig. 3 shows curves of the oxygen and hydrogen overvoltage on different electrodes against a matted calomel electrode as a comparison electrode with 5.5 normal potassium liquor as electrolyte at 100 ° C. The reversible oxygen and Tate potential is found amen on the diagram.

Claims (4)

Patentansprak:Patent claim: 1. Elektrolyscell for vattensonderdelning am unipolar eller bipolar typ, kannetecknad av Raney-nickel i form ay ett dubbelskelett som katod eller som aktiv belaggning pa katoden eller some tillsats till katodmaterialet och av Raney-nickel som anod eller Raney-nickel, Raney-silver eller silver som aktiv belaggning i form av dubbelskelett pa anoden eller dessa metaller som tillsats till anodmaterialet.Electrolysis cell for unipolar or bipolar type water subdivision, characterized by Raney nickel in the form of a double skeleton as cathode or as active coating on the cathode or as an additive to the cathode material and by Raney nickel as anode or Raney nickel, Raney silver or silver as an active coating in the form of a double skeleton on the anode or these metals as an additive to the anode material. 2. Elektrolyscell enligt patentanspraket 1, kannetecknad ay att elektroderna besta av ett mekaniskt fast material, som framstallts pa i och for sig kant salt genom blandning av pulverformig legering av nickel eller silver och med en. utlosbar metall, rent nickel- eller silverpulver med efterfoljande pressning, sintring och ullosning av den utlosbara metallen.2. An electrolytic cell according to claim 1, characterized in that the electrodes consist of a mechanically solid material, which is produced on per se edge salt by mixing powdered alloy of nickel or silver and with a. releasable metal, pure nickel or silver powder with subsequent pressing, sintering and unwinding of the releasable metal. 3. Elektrolyscell enligt patentanspraket 1 eller 2, kannetecknad ay att elektrodmaterialet framstallts av med sadana inangder pul- 203 763 verformig legering och rent nickel- eller silverpulver, att forhallandet mellan legering och nickel eller silver utgor ungefar 1.3. An electrolytic cell according to claim 1 or 2, characterized in that the electrode material is made of such alloyed powder alloy and pure nickel or silver powder, that the ratio between alloy and nickel or silver is approximately 1. 4. Elektrolyscell enligt patentanspraken 2 och 3 med unipolara anoder av Raney-silver och silver, kannetecknad av att .ett diafragma, mellan katod och anod, som fir besthndigt gentemot silverperoxid och ogenomslappligt for silverjoner. AnfOrda publikationer: Patentskrifter Iran Frankrike 1 132 762; Schweiz 161 836; Tyskland 1 019 361; USA 1 423 171.4. An electrolytic cell according to claims 2 and 3 having unipolar anodes of Raney silver and silver, characterized in that a diaphragm, between cathode and anode, which is resistant to silver peroxide and impermeable to silver ions. Cited publications: Patents Iran France 1,132,762; Switzerland 161,836; Germany 1,019,361; USA 1 423 171.