Behavior of the longitudinal particle mixing in a screen-packed fluidized bed was studied for a basic research on the regeneration of activated carbon. Main factors chosen for the effect on the process were gas velocity, particle size and mesh size of screen packing.
The mean diameter of the fluid particle were 0.302, 0.151, and 0.097mm and the packings were 1cm. × 1cm. open-end cylinders made of 8, 10 and 12 mesh/in. stainless steel screen.
A dispersion model was well fitted to the experimental data of the longitudinal particle mixing in a screen-packed fluidized bed.
The axial dispersion coefficient was successfully correlated with mean particle diameter($\bar{d}$p), mesh opening($\imath$), and gas velocity (U/$U_{mf}$ -1), and the following empirical equation was obtained.
$D_e=2.5(\imath)^{0.9}(\bar{d}p)^{-0.1}(U/U_{mf}-1)^{0.9}$
The effects of pulse on the screen-packed fluidized bed was also studied. The results showed that the axial dispersion coefficients were higher than normal screen-packed fluidized bed when the mean particle diameter of fluid particle was 0.151mm., and the ratio of on-period to off-period was 1.0, and amplitudes of the pulse were 3.64, 5.46 and 7.28.
Activated carbon regeneration의 기초 연구로서 입자의 크기, 유속, screen-packing 의 mesh size에 따른 axial dispersion coefficient 의 영향을 비교 연구하였다.
유동 입자는 평균직경이 0.302, 0.151, 0.097mm 인 Activated carbon을 사용하였으며, 8, 10, 12 mesh/in, 1cm × 1cm 의 screen-packing 을 사용하였다.
screen-packed fluidized bed 에서의 axial solid mixing은 dispersion model 이 잘 적용되며, axial dispersion coefficient 는 평균 입자 직경 ($\bar{d}_p$), screen-packing 의 mesh opening ($imath$), 유속들과 좋은 상관관계가 얻어졌으며, 다음과 같은 실험식이 얻어졌다.
$D_e=2.5(\imath)^{0.9}(\bar{d}_p)^{-0.1}(U/U_{mf}-1)^{0.9}$
또한 screen-packed fluidized bed 의 pulse 의 영향도 연구하였다. 입자의 평균 직경 0.151mm, 8, 12 mesh /in packing, pulse frequency $0.5 \sec^{-1}$, on-period와 off-period의 비가 1.0, 그리고 amplitude 가 3.64, 5.46, 7.28 cm 일 때 같은 조건의 screen-packed fluidized bed 에서 보다 더 높은 axial dispersion coefficient 가 얻어졌다.
