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Detailed simulations of industrial‐scale fluidized beds such as the FINEX process are still unfeasible due to the wide range of spatial scales. Due to the computational limitations it is common to apply coarse grids, which do not resolve all relevant structures. In our previous study (Schneiderbauer, AIChE J. 2017, 63, 3562), we have presented subgrid models, which enable the coarse grid simulation of dense large‐scale gas–solid flows. Herein, these corrections are applied to a parcel‐based the dense discrete phase model (DDPM), allowing to study the hydrodynamics of the FINEX process. Furthermore, the parcel approach is augmented by an unreacted shrinking core model (USCM) to account for the direct reduction of the iron ore particles by the reducing agents of H2 and CO. This DDPM model is tested first for a cold pilot‐scale fluidized bed, and second, the USCM approach is validated for the direct reduction in a lab‐scale fluidized bed. Finally, the model is applied to the FINEX process. The results show fairly good agreement with measurements of the average bed voidage and with experimentally determined particle size distributions. The results further indicate that fines are immediately reduced, whereas the reduction of the largest ore grains takes considerably longer.

A simulation program for the calculation of X-ray diffraction curves (Bragg case) on the basis of the dynamical diffraction theory was developed. The strain distribution in the sample is modelled as a sequence of a large number of arbitrarily strained layers with no limitation on the reflectivity of the individual layers. The program was used for the investigation of the strain induced by Ge ions implanted into Si wafers and the strain in short-period II-VI superlattices.

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Identifying coals suitable for blast furnace injection has become increasingly important due to rising injection rates. This review of traditional pulverised coal reactivity testing equipment reveals that no agreed-upon evaluation standard exists and that different reactor types are employed for testing. Therefore, reference blast furnace conversion conditions are defined, followed by a discussion of their influence on the coal conversion process as illustrated by conceptual conversion models. Critical process parameters are temperature, heating rate and pressure, while other effects can be calibrated. Evaluating the currently employed test equipment with regard to these process parameters shows that only specially designed drop-tube furnaces and flow reactors provide conversion conditions near to blast furnace conditions. For consistent injection coal testing, special reactors complying with the previously defined critical process parameters must be established.