Optimization of Scrap Preheating in Hot Metal Ladles by Computational Modeling to Address Disordered Packing
摘要
The preheating of scrap steel within a hot metal ladle exerts a notable influence on reducing energy consumption and enhancing smelting efficiency within the steel industry. Nevertheless, the intricacies associated with the varied geometric configurations of scrap steel, along with the porosity in its packaging, pose significant challenges for traditional experimental methodologies in accurately depicting this process. Existing research frequently leans on oversimplified homogeneous models, which fall short of capturing the intricate heat transfer mechanisms prevalent in the random packing of diverse scrap types. Consequently, this limitation hinders the optimization of the process. To address this, an innovative approach by utilizing numerical simulation to develop a three-dimensional scrap model was introduced. This model inclusively incorporates light-gauge scrap, light scrap, medium–heavy scrap, and bales, all under conditions of random packing. Using Ansys Fluent 2023, the scrap preheating process in the hot metal ladle was simulated, investigating the effects of fuel flow rate, heating duration, and nozzle angle on the process. The study thoroughly analyzed the flow field, temperature distribution, scrap temperature rise, and gas utilization efficiency within the ladle. The results indicate that increasing the flow rate from 600 m3/h to 1200 m3/h raises the average scrap temperature from 868 K to 1003 K, with a 45-K increase per 200 m3/h increment. Extending the preheating time from 10 min to 25 min elevates the average surface temperature from 778 K to 989 K, with a 70-K rise per 5-min extension, albeit at a 4.1% reduction in preheating efficiency. Optimal nozzle angles were identified as 5°–10° for light scrap and 15°–20° for medium–heavy scrap. Each 5° increase in nozzle angle reduces the scrap surface temperature by 20 K and gas preheating efficiency by approximately 1.2%. These findings provide a theoretical basis for optimizing practical scrap smelting processes, contributing to the low-carbon development of the steel industry.