Views: 2 Author: Site Editor Publish Time: 2025-01-10 Origin: Site
The flue gas produced by the sintering machine of the iron and steel enterprise is large in volume, high in temperature and high in humidity, and the enterprise adopts the finned tube heat exchanger for whitening in the flue gas purification system.
Flue gas volume: Sintering machines produce a large amount of flue gas during the production process. This is because sintering is a large-scale material handling process, in which a large amount of ore powder, fuel and flux are sintered at high temperatures, generating a flue gas volume of up to hundreds of thousands of cubic meters per hour. Such a huge amount of flue gas is a test of the finned tube heat exchanger's processing capability, requiring the heat exchanger to have a sufficiently large heat transfer area and a suitable structural design to ensure that it can handle all the flue gas.
Temperature: The temperature of the sintered flue gas is high, generally between 120 - 300℃. High temperature flue gas on the one hand, the finned tube heat exchanger high temperature performance requirements, the need to choose the right material to make finned tube, such as high temperature alloy steel; on the other hand, high temperature also means that the potential for heat recovery is greater, if this part of the heat can be effectively utilized, you can achieve better energy saving effect.
Moisture content: As the raw materials may contain some moisture during the sintering process, or there is moisture generation during the sintering process, the flue gas contains a large amount of moisture. This makes it necessary to focus on the condensation of water vapor during the whitening process. A large amount of water vapor in the cooling process if not effectively condensed, it is difficult to eliminate the white plume phenomenon.
Advantages of finned tube heat exchanger in sintering machine flue gas cleaning
Highly efficient heat transfer: The finned tube heat exchanger can effectively reduce the temperature of the flue gas. The fin structure increases the heat transfer area, which enables the heat to be quickly transferred from the high temperature flue gas to the cooling medium. For example, the heat transfer coefficient of the heat exchanger can be increased by several times compared with that of an ordinary light tube heat exchanger by reasonably designing parameters such as the shape, spacing and height of the fins. In sinter flue gas treatment, this highly efficient heat transfer helps to quickly reduce the flue gas temperature to below the dew point temperature, prompting condensation of water vapor and thus reducing the white smoke plume.
Adaptable structure: The finned tube heat exchanger can be flexibly designed according to the actual flue gas volume and site space. For the large amount of flue gas produced by the sintering machine, the treatment requirements can be met by increasing the number of finned tubes and adopting multiple parallel or series connection. At the same time, it can be adapted to different installation locations and piping routes, facilitating integration with existing sinter flue gas purification systems.
Waste heat recovery potential: While lowering the flue gas temperature, the finned tube heat exchanger can recover a large amount of heat. This recovered heat can be used to preheat the sintered material, heat water, or other processes that require thermal energy. For example, the recovered heat can be used to preheat the mixture entering the sintering machine, which can improve the sintering efficiency, reduce the fuel consumption and realize energy saving and emission reduction.
Specific Details of Finned Tube Heat Exchanger
Material selection: Considering the high temperature and high moisture content of the sintering flue gas, as well as the possible corrosive components (e.g., sulfur dioxide, etc.), the base tube material of the finned tubes is usually made of materials with good corrosion resistance and high temperature resistance, such as 316L stainless steel. The fin material can be either aluminum or stainless steel, with aluminum having good thermal conductivity and stainless steel being more corrosion resistant.
Fin Parameter Design: The fin spacing is generally determined by the dust content of the flue gas. As the sintering flue gas contains a certain amount of dust, the fin spacing can not be too small, so as not to cause clogging. Typical fin spacing is between 6 - 10mm. The height and thickness of the fins will also be designed based on heat transfer calculations and strength requirements, for example, the fin height may be between 10 - 20mm and thickness between 0.5 - 1.5mm to ensure that the heat transfer area is maximized without affecting the flow of flue gases.
Cleaning and Maintenance: Finned tube heat exchangers are prone to scaling and clogging due to the presence of dust and other impurities in the sintered flue gas. Therefore, regular cleaning and maintenance is required. Cleaning methods may include high pressure water flushing, chemical cleaning, etc. When designing, consideration will also be given to reserving cleaning channels and maintenance windows to facilitate operators to clean and inspect the finned tubes.
White Plume Elimination Effect
Elimination of white plume: Through the cooling and condensing effect of the finned tube heat exchanger, the water vapor in the flue gas condenses in large quantities, and the phenomenon of white plume is obviously reduced. When the treated flue gas is discharged, the visual pollution is significantly reduced, which is in line with environmental protection requirements.
Synergistic reduction of pollutants: In the process of water vapor condensation, some soluble pollutants in the flue gas (e.g., sulfuric acid mist, etc.) will also condense and be removed. This not only helps in whitening, but also reduces the content of other pollutants in the flue gas and improves the ambient air quality. For example, in some applications, the sulfuric acid mist content in the flue gas can be reduced by 30% - 50% after treatment with a finned tube heat exchanger.
