| Popis: |
In order to comprehend phenomena of particle movement and accumulation around a dead man in a blast furnace, they were modeled by segregation of solids mixture over an inclined heap surface under multi-point feed. Utilizing a two-dimensional vessel, the flow and packing characteristics over the dead man were experimentally and analytically investigated with the lapse of operational time. Thus, varying the feed rate along the heap surface and the composition of the feed mixture, the distributions of the flowing-down velocity and the composition, and its change in the packed zone inside the heap were measured by means of a video system.According to the experiments, the multi-point feed creates increase in the flowing-down velocity along the heap surface and upwards. In case of a static heap, the fraction of a segregating component of lower flowability such as smaller or denser particles exhibits the maximum along the surface inside the heap and increases with higher initial mixing fraction and lower feed rate. While, in case of a descending heap, the fractional peak shifts downwards and gets broad with higher descending velocity. Those trends become conspicuous with larger difference in particle size and density.The effects of the feed rate, the feed composition, and the descending speed of the heap were quantitatively explained on the segregation pattern inside the dead man by expanding Shinohara's screening-layer model for one-point feed to the present situation of multi-point one. |
