Numerical simulation and optimization of the flow in the sintering flue gas circulating hot air hood

The flue gas circulation technology is a new type of sintering mode developed based on the principle of the reintroduction of part of the hot exhaust gas into the sintering process. It has considerable effects on improving the utilization rate of the sintering waste heat and reducing pollutant emissions and sintering energy consumption. However, the circulating flue gas flow state in the flue gas hood and air leakage of the flue gas hood are critical to the effect and stability of the flue gas circulation. Simultaneously, they have a considerable impact on the quality indicators of the sintered ore. To optimize the circulating flue gas flow state in the flue gas hood, improve the air leakage of the flue gas hood, and maximize the advantages of low pollution and low emission of the flue gas circulation sintering technology, this study simulated the flue gas flow status in the circulating flue gas hood of a steel plant and the air leakage situation. Results show that although the strength of the smoke entering to form the vortex is weakened to a certain extent when the existing smoke hood manhole is opened, the swirling flow of the smoke is not improved, resulting in the uneven flow velocity of the smoke on the material surface. Moreover, evident air leakage of the flue gas hood is observed. By optimizing the structure and number of baffles in the flue gas hood, the rotating flow of the flue gas in the flue gas hood is weakened, the circulation of the flue gas flow considerably improved, and the flue gas distribution is more uniform. Simultaneously, the air leakage of the gas hood greatly improved. After optimization, the air leakage on the side changes from a leakage of 1.2 m³·s⁻¹ to a suction of 2.4 m³·s⁻¹, which is conducive to the smooth movement of the sintering production.