RU2399697C1 - Gas collecting bell of aluminium electrolytic cell with self-baked anode - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: gas collecting bell of aluminium electrolytic cell with self-baked anode consists of straight and angular hinged sections in form of chambers together with anode forming channel for gases flow,and of seat branches for burners made in form of truncated cones and positioned on two angular sections. The branches are equipped with doors for removal of deposits. Also the seat branches for burners correspond to truncated cones and are arranged on walls of the angular sections of the gas collecting bell. Notably, ratio of volume of a truncated cone to volume of the channel for gas flow under the angular section of the gas collecting bell is within ranges (0.2÷0.8):1.

EFFECT: raised efficiency of after-burning anode gases in burners.

2 dwg

Description

The claimed invention relates to non-ferrous metallurgy, in particular to the production of aluminum in electrolytic cells with a self-baking anode and top current lead, and is aimed at increasing the efficiency of surviving anode gases in burners.

Known gas collection bell, consisting of straight and angular sections suspended around the perimeter of the anode casing of the electrolyzer [Basov A.I., Eltsev F.P. Handbook of mechanics of non-ferrous metallurgy plants. M.: Metallurgy, 1981. - 495 p.].

However, the use of the known gas collection bell does not allow for stable operation of the burners. This is due to the fact that the pipe intended for installation of the burner and made in the form of a rectangular elbow is susceptible to overgrowing with dust deposits that impede the entry of gases into the combustion zone.

Known bell collector aluminum electrolyzer [RF Patent No. 2303660, publ. July 27, 2007], taken as a prototype. The gas collector is made of straight and corner mounted sections in the form of chambers, which together with the anode form a channel for the passage of gases. Landing nozzles for burners are made in the middle and lower part in the form of hollow half-cylinders and are located on the tides of two corner sections.

However, the use of the known bell gas collector does not ensure that the temperature of the gases at the inlet to the burner is at a level sufficient to ignite. This is due to the fact that the landing pipes play the role of dust precipitation chambers that prevent the removal of dust from under the gas collection bell into the burner. As a result, a layer of deposits is formed on the surface of the melt, directly under the landing pipe, which is a heat insulator that prevents the heating of gases to the temperature of the melt. Removing dust deposits from under the landing pipe is difficult due to the inconvenience of access to them. The latter is due to the design features of the landing pipe, the inner cavity of which extends beyond the outer dimensions of the corner section of the bell gas collector.

The main objective of the invention is to increase the efficiency of afterburning of the anode gases in the burners.

This is achieved by the fact that the gas collection bell 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 two corner sections, landing pipes for burners with hatches for removing deposits, landing pipes for burners are made in the form of truncated cones and are located on the walls of the corner sections of the gas collection bell, while the ratio of the volume of the truncated cone to the volume of the channel for the passage of gases under the corner sec iey gas collection bell is within (0,2 ÷ 0,8): 1.

Landing nozzles are made in the form of truncated cones and are located on the walls of the corner sections. This arrangement of the nozzles ensures that the temperature of the gases at the inlet of the burner is maintained at a level sufficient to ignite the gas mixture due to the proximity of the surface of the melt; allows you to use excess pressure in the channel for the passage of gases to create the necessary differential pressure in the burner; eliminates the risk of overgrowth of the burner cavity by dust deposits; provides the convenience of removing dust deposits from the surface of the melt. The landing pipe in the form of a truncated cone creates less, in comparison with the prototype, aerodynamic resistance to the movement of gases from the gas duct to the burner.

The ratio of the volumes of the truncated cone to the volume of the channel for the passage of gases under the corner section of the gas collection bell is selected for the following reasons. The use of a truncated cone with a volume smaller than 0.2 of the volume of the gas duct under the corner section of the gas collection bell creates high aerodynamic resistance to the movement of gases from under the gas collection bell to the burner device due to the fact that at the entrance to the landing pipe there is a collision of two oncoming flows moving from under the longitudinal and end sides of the poplar space. The use of a truncated cone with a volume exceeding 0.8 of the volume of the gas duct under the corner section of the gas collection bell significantly increases the dimensions and weight of the corner section.

The essence of the invention is illustrated by drawings. Figure 1 shows a fragment of a gas collection bell, including an angular section. Figure 2 is a view A-A of figure 1.

The gas collection bell, including straight 1 and angular 2 sections, is mounted around the entire perimeter of the anode casing 3 using a belt 4, thus forming a channel for the passage of gases 5, bounded below by the surface of the melt 6. The landing pipe 7 for installing the burner is made in the form of a truncated cone and located on the wall of the corner section. Removing deposits from under the gas collection bell is carried out through the hatch 8.

The gas collection bell works as follows. The anode gases formed in the electrolyzer through the channel 5, formed by the anode casing 3, the belt 4, the straight 1 and the corner 2 sections and bounded below by the surface of the melt 6, move to the corner sections 2. From under the corner section, the anode gases through the pipe 7 enter the burner to burned down. Dust particles carried away by the gas stream from the surface of the melt 6 are deposited under the nozzle 7. The removal of the settled particles is carried out through the hatch 8 located in the landing nozzle.

The advantages of the claimed invention are: maintaining the temperature of the gases at the inlet of the burner at a level sufficient to ignite the gas mixture; the use of excess pressure in the channel for the passage of gases to create the necessary differential pressure in the burner; convenience of removal of deposits from under a gas collecting bell.

Claims (1)

Gas collecting bell of an aluminum electrolyzer with a self-baking anode, containing straight and angular hinged sections in the form of chambers, forming, together with the anode, a gas passage, located on two corner sections, landing nozzles for burners with hatches for removing deposits, characterized in that the landing nozzles for burners made in the form of truncated cones and located on the walls of the corner sections of the gas collection bell, the ratio of the volume of the truncated cone to the volume of the channel for the passage of gases under the corner section th gas collection bell is in the range (0.2 ÷ 0.8): 1.

Images