CN-122003288-A - Gas purification module in aluminum electrolysis process and purification method thereof

Abstract

The gas purification module for collecting and purifying the gas generated by the aluminum production electrolytic tank comprises at least two adsorption reactors (1), wherein the adsorption reactors are connected with a bag filter (2) through a transition pipeline (3), and the bag filter consists of a dust-containing gas chamber (4), a gas purifying chamber (5), a filter bag (6) and a fluorinated alumina storage bin (7). The module includes two sorbent feed lines. The first adsorbent supply line is used for conveying pure alumina to the adsorption reactor (1) and the pneumatic lifting device (9) so as to spray the pure alumina on the filter bag (6). The second sorbent feed line is configured to deliver fluorided alumina to the sorbent reactor and the electrolyzer via a pneumatic lifting device (11). The technical effect is to improve the purifying efficiency of fluorine-containing gas in a single electrolytic tank adopting different electrolytic processes.

Inventors

• Victor Christianovich Mann
• Vyacheslav Georgievich Sergei Grigoryev
• Sergei Victorovich Jiepi Gold
• Alexei Dmitrievich Shemet
• Dmitry Vladimirovich Vysotsky
• Anton Alexeyevich Illiyenko

Assignees

• 俄罗斯工程技术中心有限责任公司

Dates

Publication Date

20260508

Application Date

20250505

Priority Date

20240522

Claims (8)

1. 1. A gas purification module for collecting and purifying gas generated in an aluminium production electrolysis cell, comprising at least two adsorption reactors (1) connected to a bag filter (2) by means of a transition duct (3), said bag filter (2) comprising a dust-laden gas chamber (4), a clean gas chamber (5), a filter bag (6) and a fluorinated alumina silo (7) divided into two sections by a transverse partition (8), characterized in that the gas purification module comprises two adsorbent feed lines, a first adsorbent feed line for transporting pure alumina and a second feed line for transporting fluorinated alumina, said first adsorbent feed line being provided with a pure alumina silo (12) with a gas distributor and at least two inclined slots for transporting pure alumina to the adsorption reactors (1), and a pneumatic lifting device (9) for spraying pure alumina to the filter bag (6), said second adsorbent feed line comprising a fluorinated alumina silo (7) arranged in the lower part of the bag filter (2) and connected to the fluorinated alumina silo (7) and transporting fluorinated alumina to the adsorption reactors (1) by pneumatic lifting device (11).
2. 2. A gas cleaning module according to claim 1, characterized in that the first and second sorbent feed lines are equipped with feed means (14.1, 14.2, 14.3) and distribution boxes (15.1, 15.2, 15.3).
3. 3. A gas cleaning module according to claim 1, which is arrangeable in the vicinity of the electrolytic cell and is connected thereto by a transfer conduit for transferring fluorided alumina as a raw material to the electrolytic cell.
4. 4. A gas cleaning module according to claim 1, characterized in that the gas cleaning module comprises a fan (21) mounted on an outlet gas line to the atmosphere.
5. 5. A method for collecting and purifying gas generated in an aluminum production electrolytic cell using the gas purifying module according to any one of claims 1 to 4, comprising the steps of (a) equally distributing dust-containing gas generated in a single electrolytic cell to two adsorption reactors, (b) transporting pure alumina from a pure alumina silo to a filter bag and/or an adsorption reactor, (c) simultaneously feeding fluorided alumina to a gas tank for recirculation and to the adsorption reactor by a feeding device and a distribution box, and further, discharging fluorided alumina from the first and/or second partition of the silo in a bag filter by overflow, and then accumulating fluorided alumina in the fluorided alumina silo for further transportation to the electrolytic cell.
6. 6. The method according to claim 5, characterized in that the supply of pure alumina to the filter bag and/or the adsorption reactor is set between 25% and 100% according to the process requirements.
7. 7. The method of claim 5, wherein the supply of fluorided alumina fed to the adsorption reactor for recirculation is between 50% and 100% depending on the set mode of operation of the production process.
8. 8. The method of claim 5, wherein the fluorided alumina is pre-heated prior to being fed into the electrolyzer.

Description

Gas purification module in aluminum electrolysis process and purification method thereof Technical Field The invention relates to aluminum production by fused salt electrolysis reduction and purification of waste gas generated in the aluminum electrolysis reduction process, in particular to gas purification equipment which can be used for dry adsorption purification of aluminum electrolysis cell waste gas. Background Methods and devices for dry gas cleaning have been developed and widely used for aluminum production, including cyclones, dust collectors, ash collectors, and various types of electrostatic precipitators, which utilize gravity, centrifugal force, and electrostatic force to clean dust and other substances in a gas and then discharge the same. The known gas cleaning processes and apparatus have the major drawbacks of being unable to remove Hydrogen Fluoride (HF) compounds, being unable to connect multiple electrolysis cells in a centralized gas cleaning unit (GTU) for off-gas treatment, the recovered adsorbent performance being averaged, high capital expenditure (CAPEX, corporate capital expenditure). There is known a combined dust collecting device (patent RU 2288782, publication date 12, 10, 2006) comprising a horizontal electrostatic precipitator followed by a vertical tube electrostatic precipitator, the effective volume ratio of the vertical electrostatic precipitator to the horizontal electrostatic precipitator being 0.1-0.9. The horizontal plate type electrostatic precipitator and the vertical pipe type electrostatic precipitator are arranged in the same shell. The electrodes in a vertical tube electrostatic precipitator are mechanically cleaned when the partition stops venting. Each partition of the tubular electrostatic precipitator is cleaned by periodic liquid flushing in the off-gas state. A disadvantage of the known technique is that the structural dimensions increase and that it is not possible to connect the filter to a single electrolytic cell for better purification regulation. An electrolytic exhaust gas purifying module (patent RU 2668926, publication date 2018, 10, 4) is known, which includes a bag filter and a reactor, wherein gas purification is performed by dry adsorption, and an adsorbent material is returned to production for use by at least one gas purifying device. The gas purifying device at least comprises a reactor, wherein the reactor is of a venturi tube structure, is designed to realize homogenization of gas flow velocity distribution, and comprises at least one self-supporting bag filter, and an inlet pipe of the reactor is arranged at the opposite side of an outlet pipe of the corresponding filter. A two-stage gas cleaning device for electrolytic gas cleaning (RU 2749421, publication No. 2021, 6, 9) is also known, which comprises at least one reactor having a venturi structure for equalizing the gas flow rate, connected to at least one bag filter by a connecting pipe, and comprising a chute for feeding the adsorbent to the reactor, a dust-laden gas chamber and a gas-purifying chamber, a filter bag and a silo. The device is characterized in that the dust-containing gas chamber and the clean gas chamber of the bag filter are divided into at least two subareas by a partition plate, and at least one subarea can be closed. The gas cleaning device also includes an adsorbent spraying system with a clean air inlet duct and is designed to allow the adsorbent to be sprayed onto the filter bag through an additional chute. Meanwhile, the connection point of the spraying system and the bag filter is positioned between the reactor and the filter, and the storage bin is at least divided into two sections and is provided with an adsorbent discharge pipe. The chute is used for conveying materials in a short distance. The chute is an open or closed chute body, usually circular or rectangular in cross section, and is installed in an inclined state so as to realize self-flow of materials. If the chute is vibrated by the vibrator, the inclination angle thereof can be greatly reduced. A common disadvantage of the known solutions is that a plurality of electrolytic cells are connected to a dry gas purification unit (DGTU), the system controls the gas purification process in a unified way, ensuring that the adsorbent usage meets the aluminium production requirements, but the performance parameters of the recovered adsorbent are averaged and the raw materials required for each electrolytic cell are not prepared individually. Each cell in the potroom has its own individual production index. The individuality of the index depends on the amount of exhaust gas discharged from the electrolytic cell, the volume of pure/recycled alumina directly fed to the electrolytic cell, the voltage drop across the anode means and the heat loss from the electrolytic cell. When using a common gas cleaning device, it is desirable to keep the temperature of the pure alumina and fluorided alumina as high as po