Systems and methods for preventing thermite reactions in electrolytic cells

Patent metadata

Field	Value
Publication number	US-9982355-B2
Application number	US-201313987650-A
Country	US
Kind code	B2
Filing date	Aug 19, 2013
Priority date	Aug 17, 2012
Publication date	May 29, 2018
Grant date	May 29, 2018

Abstract

A method of monitoring an electrolytic cell including detecting information indicative of a thermite reaction, comparing the information indicative of a thermite reaction to a threshold, generating a thermite response signal according to the comparison, and reacting to the thermite response signal by adjusting the operation of the electrolytic cell.

First claim

What is claimed is:

1. A method of monitoring an electrolytic cell, comprising:
measuring a voltage, by one or more voltage probes, across an anode distributor plate, wherein the one or more voltage probes are attached to only an anode assembly at one or more respective locations to detect voltage information indicative of a thermite reaction, wherein the anode distributor plate is configured to attach to and electrically communicate with a group of metal oxide anodes;
receiving, by a monitoring device, the voltage information from the one or more voltage probes;
comparing, by the monitoring device, the voltage information to a threshold voltage drop, wherein the threshold voltage drop is a voltage drop level previously associated with a thermite reaction, and wherein the threshold voltage drop is a rate of voltage drop increase;
generating, by the monitoring device, a thermite response signal when the voltage information matches or exceeds the threshold voltage; and
causing, by a control system, in response to the thermite response signal at least one adjustment in at least one operational parameter of the electrolytic cell to suppress the thermite reaction, wherein the electrolytic cell comprises a cathode, an anode assembly comprising one or more anode distributor plates and an electrolytic bath.

2. The method of claim 1 , wherein the measuring the voltage comprises measuring the voltage drop from a plurality of anode distributor plates, wherein each distributor plate is configured to attach to and electrically communicate with the group of metal oxide anodes.

3. The method of claim 2 , wherein the voltage information indicative of a thermite reaction comprises information related to an electrical current passing through one or more anodes of the group of metal oxide anodes.

4. The method of claim 3 , wherein the voltage information indicative of a thermite reaction comprises at least one of a magnetic field associated with one or more anodes of the group of metal oxide anodes, an electrical field associated with the one or more anodes, and a voltage associated with the one or more anodes.

5. The method of claim 4 , wherein the voltage information indicative of a thermite reaction comprises a voltage drop associated with one or more anodes of the group of metal oxide anodes.

6. The method of claim 4 , wherein the voltage drop is detected across known points in each of one or more anodes of the group of metal oxide anodes.

7. The method of claim 4 , wherein the voltage drop is detected across known point in an anode distribution plate supporting a group of one or more anodes of the group of metal oxide anodes.

8. The method of claim 4 , wherein the voltage drop is detected across known point in an anode assembly supporting one or more anodes of the group of metal oxide anodes or one or more anode distribution plates.

9. The method of claim 2 , wherein the voltage drop is detected across an anode assembly supporting the plurality of distributor plates, with each distributor plate configured to attach to a respective group of anodes.

10. The method of claim 5 , wherein the comparing of the voltage information to a threshold voltage comprises comparing the voltage drop associated with one or more anodes of the group of metal oxide anodes to a threshold voltage drop.

11. The method of claim 10 , wherein the threshold voltage drop is based on past operational data of the electrolytic cell.

12. The method of claim 10 , wherein the threshold voltage drop is a computer derived threshold derived from one of past operational data of the electrolytic cell or operation parameters and composition of the electrolytic cell.

13. The method of claim 1 , wherein the generating of the thermite response signal according to the comparison comprises generating the thermite response signal if the detected voltage drop indicates a sudden rise of voltage drop across one or more anodes of the group of metal oxide anodes.

14. The method of claim 1 , wherein the generating of the thermite response signal according to the comparison comprises generating the thermite response signal if, when compared to the threshold, the detected voltage drop indicates a sudden rise of voltage drop across one or more anodes of the group of metal oxide anodes.

15. The method of claim 1 , wherein the generating of the thermite response signal according to the comparison comprises generating a standby signal as the thermite response signal if the detected voltage drop does not match or exceed the threshold voltage drop.

16. The method of claim 15 , wherein the generating of the thermite response signal according to the comparison comprises generating a standby signal as the thermite response signal if, when compared to the threshold, the detected voltage drop does not indicate a sudden rise of voltage drop across one or more anodes of the group of metal oxide anodes.

17. The method of claim 16 , wherein the reacting to the thermite response signal comprises continuing detecting information indicative of a thermite reaction when the thermite response signal is a standby signal.

18. The method of claim 14 , wherein the reacting to the thermite response signal comprises sending a signal to an operator of the electrolytic cell.

19. The method of claim 1 , wherein causing, by a control system, in response to the thermite response signal at least one adjustment in at least one operational parameter of the electrolytic cell to suppress the thermite reaction comprises one or more of changing the ACD of one or more anodes of the group of metal oxide anodes, moving one or more anodes of the group of metal oxide anodes, removing one or more anodes of the group of metal oxide anodes from an electrolytic bath, changing a current supplied to one or more anodes of the group of metal oxide anodes, changing a temperature of the electrolytic bath, changing an electrolytic bath chemistry, removing the electrode assembly from the electrolytic bath, changing the electrical current supplied to the electrolytic cell.

20. The method of claim 19 , wherein the magnitude of the thermite response signal corresponds to the magnitude of the detected voltage drop, and wherein the causing, by a control system, in response to the thermite response signal at least one adjustment in at least one operational parameter of the electrolytic cell to suppress the thermite reaction is commensurate to the magnitude of the thermite response signal.

21. A method of monitoring an electrolytic cell, comprising:
measuring a voltage drop, by a plurality of voltage probes, between two points on an anode to detect voltage drop information indicative of a thermite reaction;
receiving, by a monitoring device, the voltage drop information from the plurality of voltage probes;
comparing, by the monitoring device, the voltage drop information to a threshold voltage drop, wherein the threshold voltage drop is a voltage drop level previously associated with a thermite reaction, and wherein the threshold voltage drop is a rate of voltage drop increase;
generating, by the monitoring device, a thermite response signal when the voltage information matches or exceeds the threshold voltage; and
causing, by a control system, in response to the thermite response signal at least one adjustment in at least one operational parameter of the electrolytic cell to suppress the thermite reaction, wherein the electrolytic cell comprises an anode, a cathode and an electrolytic bath.

Assignees

• Alcoa Inc
• Alcoa Usa Corp

Inventors

• D'Astolfo Leroy E
• Steiner William J
• Moreland Eric C
• Kozarek Robert L
• Ruan Yimin

Classifications

• C25C7/06

  Operating or servicing · CPC title

• C25C3/20 Primary

  Automatic control or regulation of cells (controlling or regulating in general G05) · CPC title

• C25D17/00

  Constructional parts, or assemblies thereof, of cells for electrolytic coating · CPC title