Steel producer interest in blast furnace hydrogen injection to reduce coke rates and carbon-related emission in-tensity has grown. Injecting hydrogen into the blast furnace has some inherent challenges, including limited utili-zation and heat balance difficulties. Injecting methane, by contrast, is a well-understood and practiced technology. Methanation of carbon-containing steel plant offgases presents an opportunity to use hydrogen in the blast fur-nace in an indirect fashion. In addition to reducing natural gas purchases, methanation has the added benefit of allowing carbon in the offgas to be recycled back to the blast furnace, rather than being emitted. This article ex-plores the use of synthetic natural gas produced from offgas as a blast furnace fuel.

To investigate the relationship between the three-dimensional characteristics of the fissure and coke size, an im-age processing method was developed for 3D medical computed tomography images to extract the fissure plane. The three-dimensional volume of the coke fissure showed a poor correlation with the coke size, whereas the plane area of the fissure showed a good correlation with the size of the coke that was not subjected to rotational impact. On the other hand, the relationship between the coke size and fissure plane area under rotational impact is not perfect, and it may be necessary to consider the effects of smaller cracks.

In the direct reduced iron (DRI) reforming process, the quality of reducing gas (i.e., CO+H2) depends on the local porosity distribution in the reformer tubes, which in turn depend on the catalyst design. In the present work, a computational fluid dynamics model is developed to simulate the industrial-scale DRI reforming process that includes the multicomponent gas mixture flow in reactor tubes and burners, reforming reactions in catalyst-filled tubes, and combustion in burners. The model predictions of tube outlet reformed gas composition and temperature are validated with plant data. The model is further used to investigate the effect of the local porosity distribution: (i) constant bed porosity and (ii) variable radial porosity due to catalyst design on the local flow field, reforming reaction rates, and ultimately on reformed gas quality and temperature.

The thermochemical conversion of alternative reducing agents (ARAs), such as pulverized coal, in the blast furnace raceway zone is a complex and hard-to-examine process due to the harsh conditions. Real-world experiments provide nonideal conversion conditions, e.g., inhomogeneous temperature and velocity and concentration fields. Ignoring these inhomogeneities falsifies the experimental results and can give mis-leading information. A digital model of an ARA test reactor is created to validate the operation conditions and evaluate potential inhomogeneities. Furthermore, the digital model will be used to reproduce experi-ments and perform detailed investigations of the particle states during conversion to identify bottlenecks during the ARA conversion.