DE2611913A1 - Thermoelectric prodn. of hydrogen and oxygen - by decomposition of higher oxide and hydrogen iodide obtd. from oxide, water and iodine - Google Patents

Thermoelectric prodn. of hydrogen and oxygen - by decomposition of higher oxide and hydrogen iodide obtd. from oxide, water and iodine

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Publication number
DE2611913A1
DE2611913A1 DE19762611913 DE2611913A DE2611913A1 DE 2611913 A1 DE2611913 A1 DE 2611913A1 DE 19762611913 DE19762611913 DE 19762611913 DE 2611913 A DE2611913 A DE 2611913A DE 2611913 A1 DE2611913 A1 DE 2611913A1
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Germany
Prior art keywords
oxide
hydrogen
oxygen
water
iodine
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Pending
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DE19762611913
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German (de)
Inventor
Friedrich Dipl Ing Behr
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Rheinbraun AG
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Rheinische Braunkohlenwerke AG
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Application filed by Rheinische Braunkohlenwerke AG filed Critical Rheinische Braunkohlenwerke AG
Priority to DE19762611913 priority Critical patent/DE2611913A1/en
Publication of DE2611913A1 publication Critical patent/DE2611913A1/en
Pending legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B13/00—Oxygen; Ozone; Oxides or hydroxides in general
    • C01B13/02—Preparation of oxygen
    • C01B13/0203—Preparation of oxygen from inorganic compounds
    • C01B13/0207—Water
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/02—Hydrogen or oxygen
    • C25B1/04—Hydrogen or oxygen by electrolysis of water
    • 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
    • Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)

Abstract

Prodn. involves an electrolysis and a thermochemical stage. In an electrolytic cell, an oxide (I) of V, Sb, As, Se, Te, Bi or U, in pure form or as alkali or alkaline earth cpd., is reacted with water and (I) at the anode to the oxide (II) with a higher 0 content and HI, whilst, at the same time, the HI is electrolysed to H and I. (II) is then removed as bottom prod., aq. soln. or hydrate melt and decomposed thermochemically, with liberation of 0. The 0 and H are removed from the process and the other prods. are recycled to the electrolytic cell. High current densities can be used and the H over-voltage is relatively low. Decompsn. voltages of 0.2-0.6 V at very high current densities can be attained.

Description

Verfahren zur Erzeugung von Wasserstoff und Sauerstoff ausProcess for the production of hydrogen and oxygen

Wasser Die Erfindung betrifft Verfahren zur Erzeugung von Wasserstoff und Sauerstoff aus Wasser mittels thermochemischer und elektrochemischer Umsetzungen (Hybrid-Verfahren).Water The invention relates to methods for producing hydrogen and oxygen from water by means of thermochemical and electrochemical reactions (Hybrid process).

Es ist bekannt, dass man mittels einer elektrolytischen Umsetzung aus Wasser Wasserstoff und Sauerstoff erhalten kann. Hierzu muss die gesamte reversible Arbeit, auch die, die der notwendigen Überspannung entspricht, mittels Elektrizität geleistet werden, wobei der Strom selbst nur mit einem relativ schlechten Wirkungsgrad hergestellt werden kann. Nachteilig ist weiterhin die geringe erreichbare Stromdichte. Gegenüber rein thermoc'hemischen Verfahren bietet eine Elektrolyse aber den Vorteil der einfachen Abtrennbarkeit der Produkte. Ausserdem brauchen keine korrosiven Komponenten transportiert und bei hohen Temperaturen umgesetzt zu werden. Hybridverfahren bieten sich dann als Alternative an, wenn sie einen elektrochemischen Schritt beinhalten, der eine hohe Stromdichte bei möglichst kleiner Zersetzungsspannung und Überspannung ermöglicht, der grösste Teil der insgesamt aufzuwendenden reversiblen Arbeit aber in eine thermochemische Reaktion eingekoppelt wird; wenn diese thermochemische Reaktion Sauerstoff abspaltet, um die Bildung einer korrosionsfesten Oxidschicht am Wärmetauscherwerkstoff zuzulassen; und wenn die thermochemische Reaktion Wärme eines sehr hohen Temperaturniveaus, wie sie zum Beispiel von einem Hochtemperaturreaktor geliefert werden kann, aufnimmt, um einen hohen Gesamtwirkungsgrad zu ermöglichen. Bei Benutzung von Gasturbinen zur Elektrizitätserzeugung sollte diese Wärmeaufnahme zwischen ca. 800 und 9000 C erfolgen, bei Einsatz eines Dampfkreislaufes oberhalb ca. 6000 C.It is known that by means of an electrolytic conversion can obtain hydrogen and oxygen from water. This must be the entire reversible Work, even that which corresponds to the necessary overvoltage, by means of electricity be made, with the electricity itself only with a relatively poor efficiency can be produced. Another disadvantage is the low achievable current density. However, electrolysis has the advantage over purely thermo-chemical processes the easy separability of the products. In addition, no corrosive components are required transported and implemented at high temperatures will. Hybrid process offer themselves as an alternative if they include an electrochemical step, which has a high current density with the lowest possible decomposition voltage and overvoltage allows the greater part of the total reversible work to be expended, however is coupled into a thermochemical reaction; when this thermochemical reaction Oxygen is split off to form a corrosion-resistant oxide layer on the heat exchanger material to allow; and when the thermochemical reaction heats a very high temperature level, as it can be supplied by a high-temperature reactor, for example, to enable a high overall efficiency. When using gas turbines to generate electricity, this heat absorption should be between approx. 800 and 9000 C, if a steam circuit is used above approx. 6000 C.

Die der Erfindung zugrunde liegende Aufgabe wird dadurch gelöst, dass man an der Anode einer Elektrolysezelle ein Oxid der Elementreihe Vanadium, Antimon, Arsen, Selen, Tellur, Wismut oder Uran in reiner Form oder als Alkali- oder Erdalkaliverbindung mit Wasser und Jod zum Oxid mit erhöhtem Sauerstoffanteil und Jodwasserstoff umsetzt, den Jodwasserstoff gleichzeitig elektrolytisch unter Freisetzung von Wasserstoff und Rückbildung von Jod spaltet, das Oxid mit erhöhtem Sauerstoffanteil als Bodenkörper, wässrige Lösung oder als Hydratschmelze aus der Elektrolysezelle abzieht und es thermochemisch unter Freisetzung von Sauerstoff spaltet, Sauerstoff und Wasserstoff aus dem Prozess entfernt und die übrigen Produkte wieder in die Elektrolysezelle zurückführt.The object on which the invention is based is achieved in that at the anode of an electrolysis cell an oxide of the element series vanadium, antimony, Arsenic, selenium, tellurium, bismuth or uranium in pure form or as an alkali or alkaline earth compound Reacts with water and iodine to form the oxide with an increased proportion of oxygen and hydrogen iodide, the hydrogen iodide at the same time electrolytically with the release of hydrogen and decomposition of iodine splits the oxide with an increased proportion of oxygen as a soil body, aqueous solution or as hydrate melt is withdrawn from the electrolytic cell and it thermochemically, releasing oxygen, splits oxygen and hydrogen removed from the process and the remaining products returned to the electrolysis cell returns.

Die reinen Oxide sind in Jodwasserstoff löslich. Ihre Löslichkeit kann durch Zusätze von Methanol vergrössert werden, gegebenenfalls auch durch Formaldehyd. Die so erhaltene Lösung ist geeignet, die Abscheidungsspannung von Jod an der Anode wesentlich zu senken. Geeignete Kathodenwerkstoffe zur Senkung der Wasserstoffüberspannung sind bekannt. Die Zersetzungsspannung von Jodwasserstoff ist bekanntlich abhängig von der Art und Konzentration der übrigen gelösten Stoffe, stärker aber von der H-J-Konzentration und der Temperatur der Lösung. Man arbeitet daher in etwa 0,1 - 2 molaler HJ-Lösing und bei erhöhten Temperaturen (40 - 2000 C), um hohe Stromdichten erreichen zu können. Mit Antimon ergibt sich z. B. ein Verfahren nach: Sb2O3 + H2O aq HJ So 204 + 2 H + 2 e aq HJ 2 H + 2e H2 Sb2O4 Sb203 + 1/2 02 (ca. 8000 - 10000 C) und mit Arsen nach: HAs02 + 2 H2 0 H3As04 + 2- H+ + 2e 2 H+ + 2e H2 H3AsO4 3/2 H20 + 1/2 As 203 + 1/2 02 (650-800° C) 3/2 H20 + 1/2 As203 HAs02 + H2 0 Die Oxide können mit verschiedenen Oxidationsstufen bzw. Sauerstoffanteilen eingesetzt werden, z. B. Vanadium unter anderem nach: 3 V2O4 + H2O V6°13 + 2 H+ + 2e 2 H + + 2e H2 V6O13 3 V2O4 + 1/2 02 (650 - 9000 C) oder nach: 2 4 H20 V2o5 + 2 H+ + 2e 2 H+ + 2e H2 V205 V204 + 1/2 02 (650 - 9000 C) Hierbei können auch, ebenso wie bei allen folgenden Verfahrensvarianten, die Sauerstoff bindenden Oxide mit weiteren Oxidationsstufen benutzt werden, so dass die zur Sauerstoffabspaltung notwendige Temperatur und Wärmemenge variierbar ist. Beispielsweise sind bei Vanadium die Oxide V203, V204, V205, V305, V407, V6013 und viele andere mehr bekannt.The pure oxides are soluble in hydrogen iodide. Their solubility can be increased by adding methanol, if necessary also by formaldehyde. The solution obtained in this way is suitable for significantly lowering the deposition voltage of iodine at the anode. Suitable cathode materials for reducing the hydrogen overvoltage are known. The decomposition voltage of hydrogen iodide is known to depend on the type and concentration of the other dissolved substances, but more strongly on the HJ concentration and the temperature of the solution. Therefore, one works in about 0.1-2 molal HJ-Lösing and at elevated temperatures (40-2000 C) in order to be able to achieve high current densities. With antimony z. B. a method according to: Sb2O3 + H2O aq HJ So 204 + 2 H + 2 e aq HJ 2 H + 2e H2 Sb2O4 Sb203 + 1/2 02 (approx. 8000 - 10000 C) and with arsenic according to: HAs02 + 2 H2 0 H3As04 + 2- H + + 2e 2 H + + 2e H2 H3AsO4 3/2 H20 + 1/2 As 203 + 1/2 02 (650-800 ° C) 3/2 H20 + 1/2 As203 HAs02 + H2 0 The oxides can be used with different oxidation states or oxygen proportions, e.g. B. Vanadium according to: 3 V2O4 + H2O V6 ° 13 + 2 H + + 2e 2 H + + 2e H2 V6O13 3 V2O4 + 1/2 02 (650 - 9000 C) or according to: 2 4 H20 V2o5 + 2 H + + 2e 2 H + + 2e H2 V205 V204 + 1/2 02 (650 - 9000 C) Here, as in all of the following process variants, the oxygen-binding oxides with additional oxidation levels can be used, so that the temperature and amount of heat required for oxygen elimination can be varied. For example, in the case of vanadium, the oxides V203, V204, V205, V305, V407, V6013 and many others are known.

Um die Löslichkeit der eingesetzten Oxide zu erhöhen und die Leitfähigkeit der Lösung zu verbesseren, kann es von Vorteil sein, das Oxid in Form einer Alkali-Verbindung einzusetzen, wobei das Verhältnis Alkalianteil/Oxid variierbar ist, z. B. mit Na , K oder besonders auch Li+ nach: a) NaH2AsO3 + H2O NaH2AsO + 2 H+ + 2e 2 H+ + 2e H2 NaH2AsO4 NaH2AsO3 + 1/2 02 b) 9 Na20 6 V204 + 3 H20 9Na20 3V204 # 3V2O5+6H+ + 6e 6 H+ + 6e 3 H2 9 Na20 # 3 V204 # 3 V205 9 Na2O # 6 V2O4 + 3/2 O2 c) Na2 0 V204 + H2O Na2 0 V205 + 2 H+ + 2e 2 H + 2e H2 Na2 0 V205 Na2O # V2O4 + 1/2 O2 Die Arbeit in schwach alkalischen Lösungen ist auch deshalb vorzuziehen, weil hier die Abscheidungsspannung von Jod wesentlich gesenkt wird. Je nach ort des eingesetzten Oxids und der Oxidationsstufe des Produktoxids sind bei Zersetzungs-Spannungen von 0,2 - 0,6 Volt sehr hohe Stromdichten erreichbar.In order to increase the solubility of the oxides used and to improve the conductivity of the solution, it can be advantageous to use the oxide in the form of an alkali compound, the alkali / oxide ratio being variable, e.g. B. with Na, K or especially Li + according to: a) NaH2AsO3 + H2O NaH2AsO + 2 H + + 2e 2 H + + 2e H2 NaH2AsO4 NaH2AsO3 + 1/2 02 b) 9 Na20 6 V204 + 3 H20 9Na20 3V204 # 3V2O5 + 6H + + 6e 6 H + + 6e 3 H2 9 Na20 # 3 V204 # 3 V205 9 Na2O # 6 V2O4 + 3/2 O2 c) Na2 0 V204 + H2O Na2 0 V205 + 2 H + + 2e 2 H + 2e H2 Na2 0 V205 Na2O # V2O4 + 1/2 O2 Working in weakly alkaline solutions is also preferable because the deposition voltage of iodine is significantly reduced here. Depending on the location of the oxide used and the oxidation level of the product oxide, very high current densities can be achieved at decomposition voltages of 0.2-0.6 volts.

Claims (1)

Patentanspruch Thermo-elektrische Verfahren zur Herstellung von Wasserstoff und Sauerstoff aus Wasser, dadurch qekennzeichnet, dass man an der Anode einer Elektrolysezelle ein Oxid der Elementreihe Vanadium, Antimon, Arsen, Selen, Tellur, Wismut oder Uran in reiner Form oder als Alkali- oder Erdalkaliverbindung mit Wasser und Jod zum Oxid mit erhöhtem Sauerstoffanteil und Jodwasserstoff umsetzt, den Jodwasserstoff gleichzeitig elektrolytisch unter Freisetzung von Wasserstoff und Rückbildung von Jod spaltet, das Oxid mit erhöhtem Sauerstoffanteil als Bodenkörper, wässrige Lösung oder als Hydratschmelze aus der Elektrolysezelle abzieht und es thermochemisch unter Freisetzung von Sauerstoff spaltet, Sauerstoff und Wasserstoff aus dem Prozess entfernt und die übrigen Produkte wieder in die Elektrolysezelle zurückführt.Thermo-electrical process for the production of hydrogen and oxygen from water, characterized in that one is connected to the anode of an electrolytic cell an oxide of the element series vanadium, antimony, arsenic, selenium, tellurium, bismuth or uranium in pure form or as an alkali or alkaline earth compound with water and iodine for Oxide with an increased proportion of oxygen and hydrogen iodide converts the hydrogen iodide at the same time electrolytically with the release of hydrogen and regression of Iodine splits, the oxide with an increased proportion of oxygen as soil, an aqueous solution or withdraws as hydrate melt from the electrolysis cell and thermochemically under it Release of oxygen splits, removes oxygen and hydrogen from the process and returns the remaining products to the electrolysis cell.
DE19762611913 1976-03-20 1976-03-20 Thermoelectric prodn. of hydrogen and oxygen - by decomposition of higher oxide and hydrogen iodide obtd. from oxide, water and iodine Pending DE2611913A1 (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2424334A1 (en) * 1978-04-28 1979-11-23 Anvar Dissociation of water into oxygen and hydrogen - involving electrolysis of aq. sulphite soln. and thermal decomposition of sulphate obtd.
FR2448579A1 (en) * 1979-02-09 1980-09-05 Kernforschungsanlage Juelich HYBRID HYDROGEN PROCESS
CN109295475A (en) * 2018-10-10 2019-02-01 陕西科技大学 A kind of preparation method of selenium doping selenizing vanadium composite material

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2424334A1 (en) * 1978-04-28 1979-11-23 Anvar Dissociation of water into oxygen and hydrogen - involving electrolysis of aq. sulphite soln. and thermal decomposition of sulphate obtd.
FR2448579A1 (en) * 1979-02-09 1980-09-05 Kernforschungsanlage Juelich HYBRID HYDROGEN PROCESS
CN109295475A (en) * 2018-10-10 2019-02-01 陕西科技大学 A kind of preparation method of selenium doping selenizing vanadium composite material
CN109295475B (en) * 2018-10-10 2020-01-21 陕西科技大学 Preparation method of selenium-doped vanadium selenide composite material

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