氢气竖炉内气固热质传递行为的数值模拟

随着对钢铁行业绿色低碳发展要求的日益迫切,氢气竖炉已成为目前涉及氢冶金工艺的研发焦点。由于H₂还原铁氧化物为强吸热反应,氢气竖炉的供气强度主要由还原反应和加热固相炉料对应的物理能需求决定,因此造成炉内物理能与化学能的利用严重不匹配。为定量研究氢气竖炉内复杂的气固两相热质传递行为,基于双流体假设,建立氢气竖炉CFD模型,并利用其考察炉料热装技术的影响。结果表明,炉料常温入炉及所考虑工况条件下,氢气竖炉的炉顶H₂利用率仅为23.7%。由于炉料显热无法得到有效利用,热装技术难以显著改善氢气竖炉内部热状态,也就不能解决物理能与化学能利用的不匹配问题。

Numerical simulation of gas-solid heat and mass transfer behavior in H2 shaft furnace

With the increasing demand of green and low-carbon development of iron and steel industry, the H₂ shaft furnace has become the focus of research and development regarding hydrogen metallurgy processes. Since the reduction of iron oxides by H₂ is strongly endothermic, the gas feed rate for a H₂ shaft furnace is mainly determined by the demand of physical energy for the endothermic reaction and the heating of solid phase, thus leading to serious mismatch between the utilization of physical energy and chemical energy in the furnace. In order to quantitatively study the complicated in-furnace gas-solid heat and mass transfer, a CFD model of H₂ shaft furnace was built based on the two-fluid hypothesis and it was used to investigate the influence of burden hot-charging operation. The results showed that H₂ utilization at the furnace top was only 23.7% when charging burden at room temperature under the considered operating conditions. Since the sensible heat of burden cannot be effectively utilized, hot-charging operation cannot significantly improve the internal thermal state of H₂ shaft furnace. Therefore, it is concluded that charging hot burden cannot address the mismatch between the utilization of physical energy and chemical energy in the furnace.