Analysing aspects of the performance of an ironblast furnace
A mathematical model has been developed, simulating various aspects of an iron blast furnace, for the purpose of analysing its behaviour. This involved the simulation of a counter current compressible gas flow, through a packed bed, dealing with the momentum and thermal energy of both phases. Directional resistances were added to the gas momentum, so as to account for the interphase friction caused by the packed bed. This enabled the prediction of the cohesive zone geometry, together with the active coke and stack, thus providing an important step for a successful analysis. The availability of multi-phase codes to solve such a system was limited and those existing being inadequate to represent these kinds of problems. What resulted was, the development of an algorithm to solve for two phases (gas and solids) with interspersed counter current flow, where the solids behaved as a packed bed. The algorithm developed is an enhanced version of existing algorithms. As well as the numerical model, a physical model of the raceway was developed, using dry ice particles to simulate the packed bed. The sublimation properties of the ice give a more realistic simulation to coke combustion, compared to the use of inert particles. The results of the experiment brought to light the effects of particle-particle interaction as being most significant in enabling the solids bed to move freely, around and into the raceway. From numerical modelling results, it is concluded that the ore:coke charging profile plays a dominant role in furnace behaviour. More interestingly, the gas distribution was not affected by raceway geometries when the cohesive zone was not in the immediate vicinity. It was therefore concluded that, the size and shape of the raceway zone has little influence on the gas distribution in the iron blast furnace.