Median residence and dispersion times for fluidization of crushed oil shale

Median residence times and dispersions for crushed oil shale flowing downward through a fluidized bed were measured as a function of particle size, nominal residence time, and fluidizing gas velocity. For fluidized beds containing narrow particle-size distribution, it was found that median residence time and dispersion increase with nominal residence time, decrease with increasing gas velocity, and show mixed results with change in particle size. The results for fluidized beds of broad particle-size distribution were different. Increasing the nominal residence time increased the median residence time but had no regular effect upon dispersion. The gas velocity was observed to have a strong effect upon dispersion but little effect upon median residence time. When particle-size effects in this broad particle-size bed were investigated, it was found that the finer particles had a longer median residence time and were more widely dispersed than the coarser particles.