RU2303660C2 - Bell like gas collector of aluminum cell - Google Patents

Abstract

FIELD: equipment for electrolytic production of aluminum, namely bell like gas collector of aluminum cell.

SUBSTANCE: gas collector includes straight and angular suspended sections in the form of chambers defining together with anode duct for gas passing. Mounting branch pipes for burners are provided in mean and in lower portions; they are in the form of hollow semi-cylinders arranged on lugs of two angular sections. Small hatches for maintaining gas collector are rectangular or elliptical and they are arranged with possibility of introducing tool into them for removing dust from lugs and coal foam from bath near anode corners. Volume restricted by lug consists of 30 - 40% of volume restricted by all angular section. Gas collector provides lowered by 1.7 times dust penetration to system of organized suction.

EFFECT: improved design of gas collector.

2 dwg, 1 ex

Description

The invention relates to ferrous metallurgy, in particular to equipment for the electrolytic production of aluminum.

The capture of gases from aluminum electrolytic cells with a self-baking anode is carried out mainly by a bell-type gas collector made of hinged sections mounted on the lower part of the anode casing. On the corner sections diagonally there are nozzles on which burner devices for burning anode gases are installed.

Known bell gas collector made of hinged sections forming a chamber for the passage of gas, with an additional closed chamber located above the main [USSR author's certificate No. 418564, IPC S25C 3/22, 1977]. An additional chamber protects the side surfaces of the anode from oxidation and insulates the anode. This device is not applicable when using the technology of the "dry" anode in electrolyzers of high power, in which intensive heat removal from the side surface is required. In addition, when installing an additional chamber, the cross section for the passage of anode gases decreases, the gas velocity and dust removal to the organized gas suction system increase.

The closest analogue to the claimed invention is a bell gas collector made of separate direct and angular mounted sections in the form of chambers, forming together with the anode a channel through which gaseous electrolysis products are removed for afterburning and cleaning [A.I. Basov, F.P. Yeltsov . Handbook of mechanics of non-ferrous metallurgy plants. M., Metallurgy, 1981, pp. 404-405]. At the edges of the sections there are docking flanges; on the tides of the two corner sections, landing nozzles for burners and hatches for cleaning the tides are made.

The design flaw of the bell gas collector is the insignificant area of the vertical and horizontal cross sections of the tide of the corner section, as a result of which the input flow rate of the anode gas in the tide of the corner section is high, which results in significant dust removal into the organized gas suction system. Existing corner sections do not allow servicing the corners of the anode without opening the electrolyzer bath. In addition, the design of the bell gas collector under consideration does not ensure the stability of the burner device, since its mixing chamber is not subject to thermal radiation from the anode body.

The objective of the invention is the development of a device for trapping anode gases, which allows to reduce dust removal in an organized suction system, to improve the service conditions of the anode angles and tides of the corner sections by increasing the size of the corner sections and the use of rectangular or elliptical hatches. The invention improves the stability of the burner devices by ensuring the tightness of the bath when it is cleaned from coal foam near the corners of the anode.

Achieving the above task is ensured by the fact that in the bell-shaped gas collector of an aluminum electrolyzer with a self-baking anode made of straight and angular mounted sections in the form of chambers, forming, together with the anode, a channel for gas passage, with landing nozzles for burners and hatches for located on the tides of two angular sections their cleaning, according to the proposed landing nozzles for burners are made in the middle and lower part in the form of hollow half-cylinders, and the hatches have a rectangular or ellipsoidal shape and size They are equipped with the possibility of introducing into them a tool for cleaning tides from dust and baths near the corners of the anode - from coal foam. Moreover, the volume covered by the tide is 30-40% of the volume covered by the entire corner section.

In relation to the prototype of the proposed device has the following distinctive features. The bottom corner section not only “sees” the cryolite melt, as in the prototype, but also relies on an alumina-cryolite crust, that is, its dimensions and, accordingly, the volume are larger. Moreover, the volume covered by the tide is 30-40% of the volume covered by the entire corner section. The burner service hatch has a rectangular or elliptical shape. The anode body “sees” the tide wall of the corner section at the gas inlet to the burner.

Between the distinguishing features and the object of the invention there is the following connection. The velocity of the anode gases in the corner section of the increased volume decreases. In this case, the angular section acts as a dust precipitation chamber, since dust is precipitated, and dust removal to the organized gas suction system is reduced, which is especially important when the baths are automatically fed with alumina, since the compressed air transporting alumina increases the dust flow.

The rectangular or ellipsoidal shape of the hatch, having a long horizontal side, allows not only dust removal from under the burner, but also coal foam near the anode angle. Maintenance of the anode angle without the usual depressurization of the bath stabilizes the operation of the burners.

The stabilization of the burner also contributes to a decrease in the hydraulic resistance of the anode gas inlet to the landing pipe, which is indirectly confirmed by the ratio of the anode gas inlet velocity to the tide of the corner section and the exit speed of the landing pipe equal to 0.7-0.8, as well as self-ignition of the gas when the flame is extinguished , since the wall of the corner section at the gas inlet to the burner is constantly heated by direct radiation from the anode body.

The bell collector is illustrated by drawings.

Figure 1 presents the angular hinged section of the bell gas collector of the anode gases of an aluminum electrolyzer. Figure 2 shows the part of the bell gas collector, consisting of two straight and one corner mounted sections.

The angular hinged section 1 consists of a casing, the flanges 2 are made at the edges of it. At high tide 3 of the angular hinged section 1, a rectangular hatch 4 and a landing nozzle for the burner 5 are made in the middle and lower part in the form of a hollow half-cylinder. Direct and angular hinged sections in the form of chambers together with the anode form a channel for the passage of gases 6. Using flanges 2, the angular hinged section 1 is joined with the direct hinged sections 7 of the bell gas collector.

The bell gas collector operates as follows. Anode gases of the electrolysis process from under the sole of the anode enter the channel for the passage of gases 6, formed by the lateral surface of the anode and straight lines 7, and angular 1 mounted sections. Under the action of the vacuum generated by the vacuum source in the gas suction network, the anode gases enter the landing pipe 5 of the tide 3 of the angular hinged section 1 and then to burn and clean the gas suction network devices. According to the calculations, the ratio of the anode gas entry velocity into the tide of the corner section and the speed of their exit from the landing pipe is 0.7-0.8, as a result of which the corner section acts as a dust collecting chamber, reducing the emission of dust flow into the gas suction network. A horizontally located rectangular hatch 4 allows maintenance personnel to introduce technological tools into the electrolyzer’s working space and to clean the tide and the bath near the corners of the anode, while stabilizing the operation of the burner devices.

The results of pilot tests conducted at the Krasnoyarsk aluminum plant showed the advantage of the proposed device compared to the prototype. The test results of the half-link electrolytic cells are presented in the table.

Table The parameters of the anode gas in the combined flue Prototype The inventive device Temperature ° C 119 113 Anode gas, nm ³ / h 4358 3563 Suspended substances (dust removal) per burner, kg / h 0.544 0.32

Compared with the prototype of the claimed device according to the data of pilot tests allows to reduce dust removal into the system of organized suction by 1.7 times.

Claims (1)

Bell gas collector of an aluminum electrolyzer with a self-baking anode, including straight and angular hinged sections in the form of chambers, forming, together with the anode, a gas passage, located on the tides of the two corner sections, landing nozzles for burners and hatches for cleaning them, characterized in that the landing nozzles for burners are made in the middle and lower part in the form of hollow half-cylinders, and the hatches are rectangular or ellipsoid in shape and placed with the possibility of introducing into them a tool for cleaning tides from dust and bathtubs near the corners of the anode from coal foam, while the volume covered by the tide is 30-40% of the volume covered by the entire corner section.

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