Numerical Calculation Of Gas Flow In Sinter Layer Of Vertical Tank For Recovering Sinter Waster Heat

Sinter waste heat recovery with vertical tank is a kind of high efficiency recovery methods, which takes example by CDQ. In essence, waste heat recovery tank is a sort of gas-particle countercurrent heat exchanger, and the heat exchange between sinter layer and cooling air takes place in the sinter void, gas flow is a major factor that influences gas-solid heat exchange. In general, the position where the gas flow is larger associated with intense heat exchange and sufficient gas-solid heat exchange. Therefore, it is important to research the rules of gas flow distribution and the resistance characteristic in the vertical tank for strengthening the gas-solid heat exchange and improving the sinter waster heat recovery efficiency. Consequently, the gas flow laws were researched in the paper.The sinter layer in the tank is unstructured fixed structure and the the layer bed geometrical factor has big changes greatly. Therefore, it is very important to study the void fraction distribution. So, the radial void fraction distribution laws were studied by using the FIAM. On account of this, the rules of gas flow distribution and the resistance characteristic in the vertical tank were obtained by adopting porous medium model and using UDF function to define the void fraction distribution. Some conclusions were drawn as follows.(1) The rule of radial void fraction distribution in material layer of vertical tankWhere, r is the distance to the wall, R is bed diameter, the void fraction has little change from the axis to the wall and increases to peak value intensely from one position near the wall to the wall.(2) The basic rule of gas flow in the vertical tank is described as follows. The gas velocity is low in the centre and high on both sides in air inlet region; The gas velocity increases slowly from the centre to the wall firstly and then increases intensely near the wall region in the cooling region. The radial velocity segregation is very obvious at the air outlet when the sinter layer height increases. The average of the radial pressure difference is0.1～0.14kPa when the superficial velocity is3-5m/s.The major factors influencing gas flow are void fraction distribution and the width of stored section, gas flow distribution uneven when the more serious the radial void fraction segregation and stored section is wider.(3) The resistance of material layer reduces gradually along the high direction in vertical tank, the resistance formula of per height.The resistance of per height material layer is about0.6～1.5kPa when superficial velocity is3～5m/s.The major factors influencing the resistance characteristic of material layer are: superficial velocity, particle diameter, void fraction. The smaller the particle diameter, the void fraction and the superficial velocity is, the larger the pressure drop of sinter layer is. The motive power of gas flow through the sinter layer is not the kinetic energy but the pressure drop. So the resistance of the sinter layer has no relationship with the inlet size.