Broadbean-like coke particles combustion in the raceway of an ironmaking blast furnace: an industrial-scale rCFD-DEM study

The gas-coke reacting flow in the raceway is a key to stable operation in an ironmaking blast furnace (BF), where real coke particles are in broadbean-like shape, however this had to be oversimplified as spherical in previous raceway models. This study develops a smooth coarse-grained (smCG) superquadric particle (SQP) reactive computational fluid dynamics – discrete element method (rCFD-DEM) rCFD-DEM raceway model and simulates the combustion of polydisperse broadbean-like coke particles in the raceway of an industrial-scale ironmaking BF. The results show that compared to the modelling of broadbean-like coke particle shapes, the spherical rCFD-DEM model underestimates the raceway size and volume while overestimating the in-raceway coke thermal-reactive performance, indicating that a more practical coke particle shape should indeed be considered directly in the future raceway rCFD-DEM modelling. The effects of the key blast conditions are then studied, including the hot blast rate, blast temperature and the mass fraction of oxygen in the hot blast. It shows that the in-raceway flow-thermal-reactive performance concerning the highly-reactive zone area and location, raceway temperature, and bosh gas composition can be more accurately quantified. This work provides a high-fidelity, cost-effective tool to better understand and further optimise the ironmaking blast furnaces for low-cost and low-carbon ironmaking.