RU2294405C1 - Anode device to aluminum cell having fired anodes - Google Patents

Abstract

FIELD: non-ferrous metallurgy, namely production of aluminum in aluminum cells with fired anodes.

SUBSTANCE: anode device of aluminum cell with fired anodes includes load-carrying beam with upper force band and lower force band having two gas discharging tubes arranged symmetrically relative to lengthwise axis of cell. Gas discharging tubes are communicated with common system for gas discharging through gas duct. Load-carrying beam has windows for placing bridges of anode buses. In order to clean gas discharging tubes they may be provided with apparatus operating, for example by action of compressed air.

EFFECT: enhanced operational reliability and effectiveness of gas collection system of cell with fired anodes, improved condition for maintaining cell.

3 cl, 2 dwg

Description

The present invention relates to non-ferrous metallurgy, in particular to the production of aluminum in electrolytic cells with calcined anodes.

Known technical solution according to the patent of the Russian Federation No. 2251593 of the Norwegian company "NORSK KHUDRO ASA" "Method and device for the operation of the electrolyzer" (C 25 C 3/22, from 11/15/2000). The device according to this patent contains an anode casing with covers made with the possibility of opening, a system for removing process gases containing at least one outlet located at the top of the anode casing and connected to the collector channel, while the system is equipped with a device for removing gases in the form of an additional exhaust fan. The presence of an additional exhaust fan ensures complete removal of process gases with open covers. This device is intended for electrolyzers with a transverse arrangement in the housing, with one-sided gas removal, with a preferred arrangement of the collector channel along the wall of the working room.

The disadvantages of this device include the following:

- with the location of the exhaust holes in the upper part of the anode casing, the entire flow of process gases is concentrated respectively in the upper zone, which requires a reliable sealing system for the entire anode casing;

- the presence of an additional exhaust fan complicates the design of the collector channel, and also requires the installation of an automatic process control system or, if there is no additional load on the process personnel;

- when equipping electrolyzers with an automatic feed system (APG), significant difficulties arise in its constructive solution.

It is known "Device for collecting and removing gases from an aluminum electrolyzer" according to the patent of the Russian Federation No. 2218453 (C 25 C 3/22 dated 05/06/2002, patent holder - JSC "VAMI"). This device is also intended for workshops with a transverse arrangement of electrolyzers and one-sided gas removal. The device includes a beam-collector with vertical walls, upper and lower stiffening belts and channels for collecting and removing gases with suction windows. The vertical walls of the collector beam are double and form two channels for collecting and removing gases located in the upper part of the collector beam, while in each of the channels, limiters are installed obliquely, forming a suction slot of constant width and variable height, and the height of the channels increases towards the end a collector beam connected to a gas exhaust system.

The disadvantages of this device are the following:

- the complexity of the design complicates both the manufacture and its installation;

- during the operation of the electrolyzer, there is a high probability of overgrowth of the suction slots;

- when the gas outlet channels are located in the upper part of the collector beam, a reliable sealing system must be implemented;

- when equipping electrolyzers with an automatic feed system (APG), significant difficulties arise in its constructive solution;

- the use of the anode busbar with busbar jumpers causes additional structural difficulties.

Also known is the “Anode device of the electrolyzer with baked anodes” according to the USSR author's certificate No. 975839 (C 25 C 3/12 of 05/25/81, the applicant - “YOU”). This device contains a load-carrying beam with upper and lower zones, gas ducts, anode busbar packages and gas flow mixing chambers. The flues are made in the form of channels located under the packages of anode tires along the entire length of the sides of the load-bearing beam, and the lower belt is equipped with gas intake windows.

According to the technical nature, design, the presence of similar, essential features, this solution was chosen as the closest analogue.

This known device provides that the entire volume of process gases is removed through the exhaust channels through both ends of the beams. Such a gas exhaust system is rational in workshops with a longitudinal arrangement of electrolyzers.

Taking into account the foregoing, we can distinguish a number of significant disadvantages of the gas exhaust system of the prototype, namely:

- the implementation of the exhaust channels in the upper part of the lower power belt requires reinforcing the design of the belt;

- the location of the exhaust ducts in close proximity to the anode tires causes difficulties both in the design and installation of the anode assembly of the cell, and in the process of maintenance of the cell during operation;

- the prototype system is ineffective in the transverse arrangement of electrolyzers with one-sided removal of process gases;

- the location of the gas collection windows in the horizontal plane does not provide effective and complete removal of gases, since the gas collection windows are not oriented towards the main torch of the evolving gases located at the periphery of the electrolyzer, and are also removed from it;

- the implementation of gas-collecting windows of the same size along the entire longitudinal side of the electrolyzer does not take into account the change in the dynamics of the formation of gas flows depending on the degree of remoteness of the windows from the general gas extraction system.

The objective of this proposal is to increase the reliability and efficiency of the gas capture system of an electrolytic cell with calcined anodes, as well as improve its service conditions.

The technical result is to increase the strength of the lower power belt of the load-bearing beam, increasing the degree of capture and removal of gases.

The technical result is achieved by the fact that in the anode device of an aluminum electrolyzer with calcined anodes containing a load-carrying beam with upper and lower power belts and with two gas exhaust channels located along the entire length of the sides of the load-bearing beam, anode tires with burnt anodes, while the lower power belt it has gas intake windows, the lower power belt of the load-carrying beam is made in the form of two exhaust pipes installed symmetrically relative to the longitudinal axis of the electrolyzer and rigidly connected between each other, and the gas intake windows are made in the lower part of the exhaust pipes and have a size with a decrease in the direction of gas movement, the anode tires are provided with jumpers, and the windows for installing these jumpers are made in the load-bearing beam, and the exhaust pipes are equipped with a pulsed cleaning device operating on compressed air.

The technical essence of the proposed solution is as follows.

In the proposed design of the anode device, the lower power belt of the load-bearing beam is simultaneously a system for capturing and removing process gases. The combination of two functions in one structural unit gives a significant gain in the design variability of the layout of the anode assembly, which is oversaturated with technological equipment, and also reduces the environmental tension of aluminum production and improves working conditions in electrolysis shops.

Unlike the prototype, in the proposed solution, the gas exhaust channels (pipes) are located under the shelter of the electrolyzer and are close to the main torch of the evolved gases, that is, to the longitudinal sides of the electrolyzer, and the gas intake windows are made in the lower outer part of the pipes and are oriented towards the rising gas flows. The gas intake window with the maximum size is located at the end of the gas outlet pipe, the opposite end connected to the common gas exhaust system, and then, as you approach the common gas exhaust system, the size of the windows decreases. This solution allows you to align the intake of process gases along the entire length of the longitudinal side of the cell with the organization of one-sided gas removal.

The proposed solution to the design of the load-carrying and gas-discharge beams frees up additional space for the installation of the most rational anode busbar.

Also, the proposed design of the anode device allows you to make windows for installing anode jumpers in the lower part of the load-bearing beam, and thus reduce the level of installation of the anode tires, which greatly facilitates the maintenance of an electrolyzer equipped with an automatic alumina feed system, as well as a centralized alumina delivery system to the electrolyzer.

To prevent overgrowth of the channels of the exhaust pipes with solid particles contained in the exhaust gas and dust streams, the proposed design is equipped with a device for cleaning them, operating in a pulsed mode using compressed air.

The closest analogue and the proposed technical solution are characterized by the following common features:

- the load-carrying beam has upper and lower power belts;

- the load-carrying beam is equipped with two gas outlet channels;

- gas exhaust channels are located along the entire length of the sides of the load-bearing beam;

- the lower power belt of the load-carrying beam is equipped with gas intake windows.

Presented by the authors of the claims claimed the following distinctive features from the prototype signs:

- the lower power belt of the load-carrying beam is made in the form of two exhaust pipes installed symmetrically relative to the longitudinal axis of the electrolyzer and rigidly connected to each other;

- gas exhaust pipes are equipped with gas sampling windows of different sizes;

- gas intake windows are made in the lower outer part of the exhaust pipes;

- the size of the gas intake windows decreases in the direction of gas movement;

- in the load-carrying beam made windows for installing jumpers, which are equipped with anode tires;

- the exhaust pipes are equipped with a device for cleaning them, for example, compressed air.

The presence in the proposed technical solution of the above signs that are different from the signs of the closest analogue allows us to conclude that it meets the patentability condition of "novelty."

In order to determine the "prior art", a search was conducted on patent and scientific literature. In the process of analysis carried out on the selected array, partially given in the description section - “analogues”, technical solutions similar to the distinguishing features of the proposed solution were not revealed, which allows us to conclude that the eligibility condition is “inventive step”.

Currently, the anode device of the proposed design is undergoing pilot testing on existing industrial electrolyzers. Preliminary operating results showed an improvement in a number of technological parameters of the electrolysis process, including gas recovery efficiency of up to 98%, which, firstly, confirms the above conclusion on the inventive step's compliance with modern requirements, and secondly, it proves the fulfillment of the third patentability condition - " industrial applicability. "

The proposed solution is illustrated by the following graphic materials: figure 1 shows a General view of the anode device, equipped with a lower power belt in the form of a vent pipe with gas intake windows; figure 2 shows a side view from the end connected to a common gas exhaust system, with a transverse section aa.

The proposed anode device of an aluminum electrolyzer with baked anodes consists of a load-bearing beam 1 with an upper power belt 2 and a lower power belt consisting of two gas exhaust pipes 3 mounted symmetrically relative to the longitudinal axis of the cell. The exhaust pipes 3 are rigidly connected by connecting elements 4, 5 and are provided with gas sampling windows 6 of different sizes. The exhaust pipes 3 are connected to a common gas exhaust system 7. The load-bearing beam 1 is provided with windows 8 for installing jumpers 9 of the anode bus 10, on which the burned anodes 11 are mounted. To clean the exhaust pipes 3 from settled dust, they can be equipped with a device 12 operating, for example in compressed air.

The proposed anode device operates as follows.

Due to the presence of two exhaust pipes symmetrically located relative to the longitudinal axis of the electrolyzer, two identical gas flows are formed, directed from the longitudinal sides of the bath to the gas intake windows, and the intake of process gases along the length of the electrolyzer is ensured by reducing the size of the gas intake windows in the direction of gas movement through the pipes . When part of the covers of the cathodic shelter is opened, for example, when replacing the anodes, the release of process gases into the atmosphere of the workshop is not observed due to the clamping of the hot process gases by cold air flows from the outside.

During operation of the electrolyzer, solid particles are entrained in the exhaust gases by the process gases, as a result of which channels can become overgrown. To prevent this, the pipes are equipped with a pulsed cleaning device operating on compressed air.

Thus, the proposed anode device provides efficient trapping and removal of anode gases.

Claims (3)

1. The anode device of an aluminum electrolyzer with calcined anodes, containing a load-carrying beam with upper and lower power belts and with two gas exhaust channels located along the entire length of the sides of the load-bearing beam, anode busbars with burnt anodes, while the lower power belt has gas sampling windows, characterized the fact that the lower power belt of the load-carrying beam is made in the form of two exhaust pipes installed symmetrically relative to the longitudinal axis of the electrolyzer and rigidly interconnected, and gas ornye window formed in the bottom of the hot gas pipes are of different size with the decrease in the direction of gas motion. 2. The anode device according to claim 1, characterized in that the anode tires are provided with jumpers, and windows for installing these jumpers are made in the load-bearing beam. 3. The anode device according to claim 1, characterized in that the exhaust pipes are equipped with a pulsed cleaning device operating on compressed air.

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