Siberian Federal University, Krasnoyarsk, Russia:

S. G. Shakhray, Assistant Professor, Chair of Technosphere Safety of Mining and Metallurgical Production, e-mail: shahrai56@mail.ru
A. P. Skuratov, Professor
A. A. Dekterev, Assistant Proffessor
N. A. Sharypov, Senior Lecturer

The gas removal system in reduction cells with a Soderberg anode has three main elements: a skirt for collection of anode gas, formed during electrolytic production of aluminum; a burner for afterburning of combustible components of anode gas; a gas flow network through which thermally neutralized anode gases are transported to gas treatment plants for final purification. The skirt is designed as a cast-iron section, hung around the perimeter of anode casing, which forms a gas channel together with the anode side surface and the melt surface. The gas collector is placed directly above the electrolyte and near the anode, i.e. at the point of emission of the pollutants, which enables a minimization of the volume of gases that are removed from the cell to 600–800 m³/h. At the same time, the volume of anode gases, formed during anode oxidation in modern aluminum reduction cells with a Soderberg anode, is  45 m³/h. The burning carbon monoxide and polycyclic aromatic hydrocarbons, released during the coking process of a Soderberg anode, are carried out in burners. These are cylindrical chambers with an anode gas supply pipe — equipped with air intake slots – in their lower part. The difference between the volume of the resulting anode gas and the volume of gases, removed from the cells, shows that the air is sucked into the burner through the air intake slots with an excess of α≥6, which has a negative effect on the stability of combustion. The gas supply network of the body of electrolysis is approximately 2–2.5 km long, and it contains a significant number of tees and sections with sudden flow expansion with a total hydraulic resistance of more than 2000 Pa, which consumes up to 30% of power generated by the exhaust fans. The paper presents the results of aerodynamic calculation of the skirt, the gas flow network, and a heat engineering calculation of afterburners. These calculations enable a comprehensive assessment of the effect that their geometric and operating mode parameters have on the efficiency and operational reliability of gas removal systems in cells with a Soderberg anode under conditions of an increasing current.

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