This article describes what is converter steelmaking and how to do a good job in dust control and explains the specific meaning of primary, secondary and tertiary dust removal.
Key words: converter steelmaking; dust; dust removal
Converter steelmaking is the main steelmaking process of my country’s iron and steel enterprises. During the blowing process, the converter produces gas with carbon monoxide as the main body, a small amount of carbon dioxide and other trace components, which also contains a large amount of iron oxide, metal iron particles and other fine particles. Solid dust, serious pollution to the atmosphere and workshop environment.
What is Converter Steelmaking?
The so-called converter steelmaking is to use molten iron, scrap steel, and ferroalloy as the main raw materials, without resorting to external energy sources, relying on the physical heat of the molten iron itself and the heat generated by the chemical reaction between the components of the molten iron to complete the steelmaking process in the converter.
According to the refractory material, the converter is divided into acidic and alkaline; according to the position where the gas is blown into the furnace, there are top blowing, bottom blowing and side blowing; according to the type of gas, it is divided into air converter and oxygen converter. Basic oxygen top-blown and top-bottom compound-blown converters are currently the most commonly used steelmaking equipment due to their fast production speed, large output, high single furnace output, low cost, and low investment.
The converter is mainly used for the production of carbon steel, alloy steel and smelting of copper and nickel.
The following is a flow chart of the converter production process:
The characteristics of its pollutants are: the dust concentration in the flue gas is high, the particle size is fine, and the pollution is serious; the flue gas temperature is high, and the complexity of the waste gas treatment process increases; Recycling conditions for comprehensive utilization.
How to control dust in steelmaking plants?
The converter in the steelmaking plant basically needs three times of dust removal. The three times of dust removal for the converter is to solve the problem of unstable molten iron composition in the process of blowing and iron mixing in steelmaking. cigarette.
After the implementation of the three dust removal renovation projects, it can effectively solve the dust removal problems such as iron mixing position, converter blowing position, converter high span position, and slag span scrap steel cutting position. At the same time, according to the operation of iron mixing, refining, desulfurization and other processes, the start and fan can be adjusted in real time to achieve the dual purposes of dust removal, environmental protection and energy saving.
Once, twice, and three times are as follows:
One time dust removal
Primary dust removal refers to the process of cooling and purifying the high-temperature flue gas generated during the blowing process of the converter through the flue. The blowing time is running at a low speed, so one-time dust removal cannot achieve the effect of dust removal.
Although the converter produces less smoke and dust during the blowing process, there is still some. At the same time, in order to recover gas during the blowing process of the converter, a certain positive pressure difference is required at the furnace mouth, which means that all the smoke and dust cannot be sucked up at one time. Go, considering that there will be a certain amount of smoke and dust escaping from the steel during blowing, and there will also be a certain amount of smoke and dust generated during the blowing process, so there are secondary and tertiary dust removal equipment.
Secondary and tertiary dust removal
In fact, the secondary and tertiary dust removal are relatively simple gravity dust removal and bag dust removal. His air inlet is generally around the flue one, connected to the dust removal equipment through the pipe. To put it bluntly, the second and third dust removal are environmental protection measures taken to make up for the deficiency of the first dust removal.
Dusty industrial waste gas may be generated from mechanical processes such as crushing, screening, conveying, and blasting of solid substances, or from processes such as combustion, high-temperature melting, and chemical reactions. The former contains dust with large particle size and the same chemical composition as the original solid substance, while the latter contains smoke with small particle size and different chemical properties from the substance that generated it. Improved production processes and combustion techniques can reduce particulate matter generation. Dust collectors are widely used to control the dust and fumes that have been generated.
The high-temperature flue gas treatment of the tertiary dust collector of the steelmaking converter is not only an environmental protection equipment but also an energy resource recovery equipment. It is also an important equipment that cannot be ignored and inseparable in the production process of the steelmaking converter. Its operation is directly related to the entire steelmaking plant. normal production and efficiency.
Therefore, when selecting a converter high-temperature and high-concentration flue gas treatment process, it is necessary to ensure that it can meet the national environmental protection requirements, and pay special attention to its operating efficiency and reliability so that it can match the rhythm of steelmaking production. To achieve the goals of controlling pollution, protecting the environment, ensuring production, saving energy, reducing emissions, and reducing consumption.