MagnitogorskIron and Steel Works (MMK) has started implementing a project for the reconstruction of a complex of gas treatment plants to capture secondary emissions in the converter department of the plant’s oxygen converter shop.
MMK's oxygen converter shop produces more than 10 million tonnes of steel per year and is one of the most powerful workshops of its kind in the world. It was commissioned in 1990, and at present, the existing capacities of the central gas treatment plant at the oxygen converter shop do not fully cope with the capture of secondary emissions from converters ¹ 1-3 and the aspiration system at the cast iron overflow units. Therefore, the main objective of the reconstruction project at the dust and gas collection units, converters ¹ 1, 2, 3, and the cast iron overflow units is to reduce emissions of polluting substances in the working space of the converter branch at the oxygen converter shop to standard values. This will be possible thanks to more efficient collection and cleaning of exhaust gases generated in the cast iron overflow unit from the mixer into the ladle, while pouring cast iron into the converter and while draining the smelt.
As part of the project, in February 2020, a contract was signed with Primetals Technologies Austria GmbH for the supply of basic engineering services and equipment for the reconstruction of the gas treatment complex at the oxygen converter shop. The contract will cost over EUR 22.3 million. The total cost of the project will be about RUB 2.5 billion.
As part of the project, the existing central gas treatment plant will be reconstructed and will only clean secondary emissions for converter No. 1 and the blast furnaces for ferro-alloys. New separate gas treatment plants will be built for converters No.2 and No.3. Also, a separate dust collection unit will carry out the removal and cleaning of exhaust gases from the cast iron overflow unit and stock houses. Collection of exhaust gases that have entered into the workspace of the oxygen converter shop will be collected by ceiling aspiration hoods over the converters with a new separate gas cleaning unit. At the same time, it is possible to further integrate the gas treatment facilities with equipment for collecting and preparing the converted gas for further use. The project is due to be completed by June 2022.
As a result of the reconstruction project, the efficiency of dust and gas cleaning will increase, and it is expected that the project will completely eliminate secondary emissions from converters into the working space of the shop, as well as emissions in all operating modes. The standard parameters for residual dust in treated gas (the concentration of suspended substances after gas treatment should not exceed 20 mg/m3), as well as the standard level of dust in the workplace (this should be no more than 6 mg/ m3) and the standard parameters for noise, vibration, and electromagnetic radiation in the workplace will be met. As such, the negative impact on the environment will be minimised. Total dust emissions from the oxygen converter shop will be reduced by at least 500 tonnes per year after the project is implemented.
The reconstruction of the converter department is not the only environmental project at MMK's oxygen converter shop. In the near future, the plant plans to start reconstruction of dust and gas collecting units and gas-discharge ducts on the assembly units at the non-furnace steel processing unit of the oxygen converter shop. This will allow for more efficient capture, cooling, transportation and cleaning of the entire volume of gases generated during "furnace to ladle" operation, electric arc steel heating, steel finishing units, vacuum units and other units of the ladle metallurgy facility at the oxygen converter shop.
Modernisation of existing facilities and construction of new environmental facilities is an important part of MMK's environmental programme, which is aimed at reducing and preventing harmful effects on the environment and covers all production processes. The goal of the programme is to introduce the best available technologies to reduce the level of environmental impact and ensure the environmental safety of technological processes.
The plant is implementing a 'Clean City' strategic initiative which should decrease the air quality index (AQI) in Magnitogorsk to 5 units by 2025, giving the city the status of a "clean city".