CFD-based optimization of an annular hydrogen direct reduction shaft furnace: geometric design and gas-feed strategy

Le résumé fourni par la source

To intensify the process of hydrogen reduction of iron oxide ore, an annular hydrogen shaft furnace (HSF) has recently been proposed to mitigate the formation of a central stagnant zone. In this work, the annular concept is thoroughly optimized with respect to both geometric design ( α , the ratio between the inner and outer radii) and gas-feed strategy ( β , the fraction of gas injected through the inner wall) using an axisymmetric two-dimensional computational fluid dynamics model. The results show that under the operating conditions considered an annular HSF with α = 0.04–0.08 provides favorable furnace performance in terms of the final solid metallization degree. From a practical standpoint, moreover, the acceptable range of α can be extended up to 0.2, where the areal productivity of metallic iron increases by about 3.8%. As for dual-side gas injection, a relatively even gas distribution with β = 0.4–0.6 significantly improves the in-furnace thermochemical state. With an increase of β , however, the pressure at inner bustle pipe increases markedly. This issue of practical relevance can be effectively addressed by adopting dual-row injection at the inner wall. The combined results provide practical guidelines for the integrated design and operation of the annular HSF for fossil-free ironmaking.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.