Design of eccentric double lance for co-injection of H2 and coal in an ironmaking blast furnace: A CFD analysis

• An eccentric double lance designed for H 2 -coal co-injection for a blast furnace. • A 3D industrial-scale CFD model provides detailed in-furnace phenomena. • The synergistic effect of H 2 and coal has been quantitatively studied. • Comparing the operation performance between single lance and double lance. The ironmaking blast furnace, the dominant ironmaking technology worldwide, is a major source of heavy-industry greenhouse gas emissions. The co-injection of H 2 and coal in the ironmaking blast furnace is a promising viable technology for cost-effective decarbonisation in the steel industry and requires innovative devices including injection lances customised for the co-injection, but such lances have not yet been designed to take account of the changed in-furnace phenomena with both hydrogen and coal. In this study, a 3-dimensional (3D) industrial-scale computational fluid dynamics (CFD) model is used to design the customised lances for the co-injection of H 2 and coal including an eccentric double lance for a commercial BF. The model is first validated based on a lab-scale experimental study of the co-injection of H 2 and coal. Then, the eccentric double lance is studied in an industrial-scale BF where a heat and mass balance (HMB) study is used to determine the operational parameters and the CFD model is used for studying the in-furnace phenomena. It was found that the eccentric double lance enhances coal particle dispersion and improves the coal burnout along the coal plume. The rapid combustion of H 2 exiting from a separate lance increases the local gas temperature in front of tuyere, also, the product, H 2 O, enhances the coal gasification by H 2 O, thus enhancing the overall coal burnout within the raceway. Details of the two high-temperature zones near the lance tips are captured, indicating a potential over-heating problem of the tuyere. The study provides a new lance design for the co-injection of H 2 and coal.