EP0185938B1 - Corrosion-resistant contact for hydrochloric-acid electrolysis - Google Patents
Corrosion-resistant contact for hydrochloric-acid electrolysis Download PDFInfo
- Publication number
- EP0185938B1 EP0185938B1 EP85114829A EP85114829A EP0185938B1 EP 0185938 B1 EP0185938 B1 EP 0185938B1 EP 85114829 A EP85114829 A EP 85114829A EP 85114829 A EP85114829 A EP 85114829A EP 0185938 B1 EP0185938 B1 EP 0185938B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- contact
- corrosion
- electrographite
- bolt
- hydrochloric
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 title claims description 14
- 230000007797 corrosion Effects 0.000 title description 5
- 238000005260 corrosion Methods 0.000 title description 5
- 238000005868 electrolysis reaction Methods 0.000 title description 4
- 229960000443 hydrochloric acid Drugs 0.000 title 1
- 235000011167 hydrochloric acid Nutrition 0.000 title 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 14
- 239000011261 inert gas Substances 0.000 claims description 8
- 229910002804 graphite Inorganic materials 0.000 description 5
- 239000010439 graphite Substances 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- 239000003792 electrolyte Substances 0.000 description 3
- 230000007704 transition Effects 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 239000002253 acid Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000004519 grease Substances 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
Images
Classifications
-
- 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
- C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
- C25B9/60—Constructional parts of cells
- C25B9/65—Means for supplying current; Electrode connections; Electric inter-cell connections
Definitions
- the present invention relates to a current contact for hydrochloric acid electrolysis cells, consisting of a metallic cap which is screwed to a bolt made of electrographite, which is hermetically sealed against the external environment and the internal aggressive atmosphere of the cell.
- FIG. 1 schematically shows a monopolar cell in which, for example, hydrochloric acid can be broken down into components C1 2 and H 2 .
- the graphite electrodes (1), (2) are connected to the graphite bolts (3), (4) via a screw thread.
- the transition to the power supply (flexible tapes) takes place via the copper screw caps (6).
- the union flange (7) and seal (8) prevent the electrolyte (9) from escaping from the cell housing (10).
- the resulting gas bubbles (13) and the electrolyte (9) are discharged together at the top (11), while fresh electrolyte is fed through an opening (12) located below.
- Anode compartment and cathode compartment are separated by a diaphragm (16).
- GB-A-1 231 044 describes current contacts between metals and graphite bolts, these screw connections having certain torques in order to achieve good electrical conductivity. Sealing of the contact is not mentioned, so that the contact point is exposed to corrosion without protection.
- the object of the present invention is therefore to provide a contact for the hydrochloric acid electrolysis which does not have the disadvantages described at the outset.
- the present invention thus relates to a current contact for hydrochloric acid electrolysis cells, consisting of a metallic cap which is screwed to an electrographite bolt, which is hermetically shielded from the external and internal environment by an inert gas, the contact point metallic cap / electrographite bolt additionally having a covering compound and / or is surrounded by an elastic ring. As a result, the outlet of the inert gas is kept low.
- the inert gas (14) can be supplied via a hose system. Nitrogen is preferably used as the inert gas. The inert gas can escape at all leaks, essentially the contact point is affected, and the inflow of a corrosive atmosphere, e.g. prevent from the cell. In order to keep the emerging quantity of inert gas low, the contact point (3-6) is also surrounded with a covering compound and / or an elastic ring (15).
- the two-sided screwing of the metallic cap with the electrographite bolt is carried out with a torque of 5 to 18 kpm, preferably 12 to 14 kpm.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
- Electrodes For Compound Or Non-Metal Manufacture (AREA)
- Electrolytic Production Of Metals (AREA)
Description
Die vorliegende Erfindung betrifft einen Stromkontakt für Salzsäureelektrolysezellen, bestehend aus einer metallischen Kappe, die mit einem Bolzen aus Elektrographit verschraubt ist, welcher hermetisch gegen die äussere Umgebung und die innere aggressive Atmosphäre der Zelle abgedichtet ist.The present invention relates to a current contact for hydrochloric acid electrolysis cells, consisting of a metallic cap which is screwed to a bolt made of electrographite, which is hermetically sealed against the external environment and the internal aggressive atmosphere of the cell.
In Fig. 1 ist schematisch eine monopolare Zelle dargestellt, in der beispielsweise Salzsäure in die Komponenten C12 und H2 zerlegt werden kann. In der industriellen Technik sind zwar überwiegend bipolare Anordnungen gebräuchlich, jedoch besteht zwischen bipolaren und monopolaren Systemen bezüglich der vorliegenden Erfindung kein grundsätzlicher Unterschied. Die Graphitelektroden (1), (2) sind mit den Graphitbolzen (3), (4) über ein Schraubgewinde verbunden. Der Übergang zur Stromzuführung (Flexbänder) erfolgt über die Schraubkappen (6) aus Kupfer. Überwurfflansch (7) und Dichtung (8) verhindern den Austritt des Elektrolyten (9) aus dem Zellengehäuse (10). Die entstehenden Gasblasen (13) und der Elektrolyt (9) werden gemeinsam oben (11) abgeführt, während frischer Elektrolyt über eine unten befindliche Öffnung (12) zugeführt wird. Anodenraum und Kathodenraum sind durch ein Diaphragma (16) getrennt.1 schematically shows a monopolar cell in which, for example, hydrochloric acid can be broken down into components C1 2 and H 2 . Although bipolar arrangements are predominantly used in industrial technology, there is no fundamental difference between bipolar and monopolar systems with regard to the present invention. The graphite electrodes (1), (2) are connected to the graphite bolts (3), (4) via a screw thread. The transition to the power supply (flexible tapes) takes place via the copper screw caps (6). The union flange (7) and seal (8) prevent the electrolyte (9) from escaping from the cell housing (10). The resulting gas bubbles (13) and the electrolyte (9) are discharged together at the top (11), while fresh electrolyte is fed through an opening (12) located below. Anode compartment and cathode compartment are separated by a diaphragm (16).
Die Problematik einer solchen Anordnung besteht darin, dass die ungleichen Werkstoffe Graphit und z.B. Kupfer am Übergang einen hohen elektrischen Widerstand aufweisen. Es hat auch nicht an Versuchen gefehlt, anstelle der Kupferkappe eine Kupferschelle zu verwenden. Der relativ hohe elektrische Widerstand erfährt aber in der Praxis eine zeitliche Zunahme infolge von Korrosionserscheinungen am Übergang. Die Folgen der Widerstandserhöhung infolge Korrosion sind erheblich.The problem with such an arrangement is that the unequal materials graphite and e.g. Copper have a high electrical resistance at the transition. There has been no lack of attempts to use a copper clamp instead of the copper cap. In practice, however, the relatively high electrical resistance experiences an increase in time as a result of corrosion phenomena at the transition. The consequences of the increase in resistance due to corrosion are considerable.
Aus der Patentschrift US-A-2 542 056 ist ein Stromkontakt bekannt, der aus einer Metallverschraubung mit einem Kohlenstoffblock besteht. Der Kontakt ist durch Gummidichtungen abgedichtet. Die Metallkappe für die Stromzuführung wird durch eine Fettfüllung geschützt. In der Praxis hat sich jedoch gezeigt, dass diese Füllung nur einen ungenügenden Schutz bietet.From US-A-2 542 056 a current contact is known which consists of a metal screw connection with a carbon block. The contact is sealed by rubber seals. The metal cap for the power supply is protected by a grease filling. In practice, however, it has been shown that this filling only offers insufficient protection.
In der GB-A-1 231 044 werden Stromkontakte zwischen Metallen und Graphitbolzen beschrieben, wobei diese Verschraubungen bestimmte Drehmomente aufweisen, um eine gute elektrische Leitfähigkeit zu erreichen. Eine Abdichtung des Kontaktes wird nicht erwähnt, so dass die Kontaktstelle ohne Schutz der Korrosion ausgesetzt ist.GB-A-1 231 044 describes current contacts between metals and graphite bolts, these screw connections having certain torques in order to achieve good electrical conductivity. Sealing of the contact is not mentioned, so that the contact point is exposed to corrosion without protection.
In technischen Zellen sind auf jeder Elektrodenseite zahlreiche Kontakte der in Fig. 1 beschriebenen Art parallel geschaltet. Im Idealfall soll der Stromdurchgang durch jeden Kontakt mit gleichem Spannungsabfall erfolgen. In der Praxis jedoch korrodieren die Kontakte untereinander ungleichmässig. Beim Ausfall eines Kontaktes verteilt sich der Strom auf die übrigen Kontakte und die auftretende Temperaturerhöhung fördert wiederum die Korrosion. Die Kontakte müssen dann unter erheblichem Arbeitsaufwand erneuert werden, was darüber hinaus zu einem Produktionsausfall führt.In technical cells, numerous contacts of the type described in FIG. 1 are connected in parallel on each electrode side. Ideally, the passage of current through each contact should have the same voltage drop. In practice, however, the contacts corrode with one another unevenly. If one contact fails, the current is distributed to the other contacts and the temperature rise that occurs in turn promotes corrosion. The contacts must then be renewed with considerable effort, which also leads to a loss of production.
Die Aufgabe der vorliegenden Erfindung besteht daher darin, einen Kontakt für die Salzsäureelektrolyse zur Verfügung zu stellen, der nicht die eingangs beschriebenen Nachteile aufweist.The object of the present invention is therefore to provide a contact for the hydrochloric acid electrolysis which does not have the disadvantages described at the outset.
Überraschenderweise wurde nun gefunden, dass diese Aufgabe dadurch gelöst wird, dass man die Kontaktstelle in bisher nicht bekannter Weise hermetisch abdichtet und somit gegen Umgebungseinflüsse schützt.Surprisingly, it has now been found that this object is achieved by hermetically sealing the contact point in a previously unknown manner and thus protecting it from environmental influences.
Der Erfolg dieser Massnahme ist um so überraschender, als die Graphitbolzen nach dem Stand der Technik, die mit Kunstharz imprägniert sind, also absolut gas- und flüssigkeitsdicht gelten.The success of this measure is all the more surprising since the graphite bolts according to the prior art, which are impregnated with synthetic resin, are therefore absolutely gas and liquid-tight.
Gegenstand der vorliegenden Erfindung ist somit ein Stromkontakt für Salzsäureelektrolysezellen, bestehend aus einer metallischen Kappe, die mit einem Elektrographitbolzen verschraubt ist, welcher hermetisch gegen die äussere und innere Umgebung durch ein Inertgas abgeschirmt ist, wobei die Kontaktstelle metallische Kappe/Elektrographitbolzen zusätzlich mit einer Abdeckmasse und/oder einem elastischen Ring umgeben ist. Dadurch wird der Austritt des Inertgases gering gehalten.The present invention thus relates to a current contact for hydrochloric acid electrolysis cells, consisting of a metallic cap which is screwed to an electrographite bolt, which is hermetically shielded from the external and internal environment by an inert gas, the contact point metallic cap / electrographite bolt additionally having a covering compound and / or is surrounded by an elastic ring. As a result, the outlet of the inert gas is kept low.
In Fig. 2 ist die erfindungsgemässe Vorrichtung dargestellt. Das Inergas (14) kann dabei über ein Schlauchsystem zugeführt werden. Als Inertgas kommt vorzugsweise Stickstoff in Frage. Das Inertgas kann an allen Undichtigkeiten, im wesentlichen ist die Konstaktstelle betroffen, austreten und das Einströmen einer korrosiven Atmosphäre, z.B. aus der Zelle verhindern. Um die austretende Inertgasmenge niedrig zu halten, wird die Kontaktstelle (3-6) noch mit einer Abdeckmasse und/oder einem elastischen Ring (15) umgeben.2 shows the device according to the invention. The inert gas (14) can be supplied via a hose system. Nitrogen is preferably used as the inert gas. The inert gas can escape at all leaks, essentially the contact point is affected, and the inflow of a corrosive atmosphere, e.g. prevent from the cell. In order to keep the emerging quantity of inert gas low, the contact point (3-6) is also surrounded with a covering compound and / or an elastic ring (15).
Um einen hohen Spannungsabfall zu vermeiden, wird die beiderseitige Verschraubung der metallischen Kappe mit dem Elektrographitbolzen mit einem Drehmoment von 5 bis 18 kpm, vorzugsweise mit 12 bis 14 kpm ausgeführt.In order to avoid a high voltage drop, the two-sided screwing of the metallic cap with the electrographite bolt is carried out with a torque of 5 to 18 kpm, preferably 12 to 14 kpm.
Erst durch die erfindungsgemässe Inertgasfüllung sind auch kontaktverbessernde, an sich bekannte Massnahmen dauerbeständig. Unter diesen wurden Beschichtungen der Graphitringfläche mit Pb oder In mit Erfolg erprobt. Der Einsatz dieser Metalle zeigt besonders deutlich die Vorteile der Erfindung. Einerseits senken sie deutlich den Spannungsabfall, andererseits sperren sie total den Strom bei geringstem Säuredurchtritt.It is only through the inert gas filling according to the invention that contact-improving measures known per se are permanently stable. Among these, coatings of the graphite ring surface with Pb or In were successfully tested. The use of these metals shows the advantages of the invention particularly clearly. On the one hand, they significantly reduce the voltage drop, on the other hand, they totally block the current with the lowest acid penetration.
Im folgenden wird die Erfindung beispielhaft erläutert, ohne dass hierin eine Einschränkung zu sehen ist.In the following, the invention is explained by way of example, without any limitation being seen here.
An einem Salzsäureelektrolyseur mit jeweils 10 Kontakten auf Anoden- und Kathodenseite in herkömmlicher Ausführung nach Fig. 1 wurden folgende Spannungsabfälle nach 1 Monat seit Inbetriebnahme gemessen:
Die hohe Verlustleistung, als Wärme abgegeben, hatte beispielsweise beim Kontakt 9 zu einem Totalausfall dieses Kontaktes und zu einer Überlastung der übrigen geführt. Diese Kontakte wurden gegen die erfindungsgemässen gemäss Fig. 2 ausgetauscht. Dabei wurde ein dauernder Druck von 0,3 bar Stickstoff aufrechterhalten. Über eine Messdauer von länger als 1 Jahr zeigten alle Kontakte innerhalb geringer Abweichung einen jeweils vergleichbaren und praktisch zeitlich konstanten Spannungsabfall. Es gab nur Unterschiede, die durch verschiedene Kontaktverbesserungen verursacht wurden.
Claims (2)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3444250 | 1984-12-05 | ||
| DE19843444250 DE3444250A1 (en) | 1984-12-05 | 1984-12-05 | CORROSION-SAFE CONTACT FOR SALT ACID ELECTROLYSIS |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0185938A1 EP0185938A1 (en) | 1986-07-02 |
| EP0185938B1 true EP0185938B1 (en) | 1988-06-01 |
Family
ID=6251897
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP85114829A Expired EP0185938B1 (en) | 1984-12-05 | 1985-11-22 | Corrosion-resistant contact for hydrochloric-acid electrolysis |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0185938B1 (en) |
| JP (1) | JPS61136690A (en) |
| DE (2) | DE3444250A1 (en) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2542056A (en) * | 1945-09-17 | 1951-02-20 | Ici Ltd | Electrode support for electrolytic cells |
| US3515660A (en) * | 1967-11-13 | 1970-06-02 | Ppg Industries Inc | Electrode stem connector,electrode assembly and electrolytic cell including the same |
| GB1231044A (en) * | 1968-08-19 | 1971-05-05 |
-
1984
- 1984-12-05 DE DE19843444250 patent/DE3444250A1/en not_active Withdrawn
-
1985
- 1985-11-22 DE DE8585114829T patent/DE3563074D1/en not_active Expired
- 1985-11-22 EP EP85114829A patent/EP0185938B1/en not_active Expired
- 1985-12-04 JP JP60271702A patent/JPS61136690A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| DE3563074D1 (en) | 1988-07-07 |
| DE3444250A1 (en) | 1986-06-05 |
| EP0185938A1 (en) | 1986-07-02 |
| JPS61136690A (en) | 1986-06-24 |
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