ESTIMATION OF VOID FRACTION AND SHAPE FACTOR IN MOVING BED OF SINTER AND COKE

The influence of size distribution of charged materials in blast furnace on void fraction and shape factor was analyzed by using a experimental apparatus in which void fraction and pressure drop under the counter-current moving bed can be measured. The relation between the void fraction and the particle diameter in uniform-sized coke and sinter is not simple, but the minimum values of the void fraction exist at a certain particle diameter. The minimum values of the void fraction in coke and sinter composed of two component particles are obtained at the range of 0.3 to 0.5 in fractional volume of fine particle. The estimation equations of the shape factor of coke and sinter are obtained so that the measured values of the pressure drop can agree with the calculated value of the pressure drop by Ergun equation. According to these equations, the shape factors of coke and sinter increase from 0.4 to 1.0 with increasing the particle diameters of coke and sinter. The estimation equation of the void fraction of sinter applicable in the actual blast furnace operation was proposed by correcting the estimation equation of the void fraction in randomly packed bed of multi-component particles, proposed by Suzuki, based on the measured values of the void fraction in the moving bed of sinter.