Modelling a DR shaft operated with pure hydrogen using a physical-chemical and CFD approach

TL;DR

This paper introduces a new numerical model, REDUCTOR, to simulate hydrogen-based direct reduction in steelmaking, showing hydrogen's faster reduction kinetics and potential for smaller, more efficient reactors.

Contribution

The paper presents the development of a novel, detailed physical-chemical CFD model for hydrogen-based direct reduction, extending the capabilities of existing models.

Findings

Hydrogen reduces steel ore faster than CO.

Hydrogen-based reduction allows for smaller reactor designs.

Model validation confirms feasibility of hydrogen operation.

Abstract

The hydrogen-based route could be a valuable way to produce steel considering its low carbon dioxide emissions. In ULCOS, it is regarded as a long-term option, largely dependent on the emergence of a hydrogen economy. To anticipate its possible development, it was decided to check the feasibility of using 100% H2 in a Direct Reduction shaft furnace and to determine the best operating conditions, through appropriate experimental and modelling work. We developed from scratch a new model, called REDUCTOR, for simulating this process and predicting its performance. This sophisticated numerical model is based on the mathematical description of the detailed physical, chemical and thermal phenomena occurring. In particular, kinetics were derived from experi-ments. The current version is suited to the reduction with pure hydrogen, but an extension of the model to CO is planned so that it will also be adapted to the simulation and optimisation of the current DR processes. First re-sults have confirmed that the reduction with hydrogen is much faster than that with CO, making it possible to design a hydrogen-operated shaft reactor quite smaller than current MIDREX and HYL.