Distribution of residence time of material being processed over the zones in type SN reactor-mixers

Abstract

Previous equations given for calculating the mean residence time of material being processed in the mixing chamber of continuous reactor-mixers show the effect on residence time of the capacity and mean reactor-mixer filling factor, the filling factor of the worm conveyor, and the mixer volume. It is necessary to take into account that such reactors operate only with ''starvation'' of the feed zone with charge. In this case the injected composition of the initial components is not disturbed. The filling factor in the zones of the guard coils of the conveyor worm becomes equal to unity over the length of the worm equal to double the length of the guard coil zones with different pitches of the guard and conveying coils. Consequently, the time of residence is not distributed uniformly over the length of the mixer but in proportion to the number of zones and the number of guard coils in the zones which are characteristic also for the mean filling factor. Experiments have been conducted in a type SN-100 reactor-mixer with an open body. After stopping the unit the upper half of the casing was opened without destroying the distribution of the material over the zones and turns ofmore » the worm. The material was removed from each zone, and the quantities were used to calculate the filling fatrors. The experimental filling factors were used to calculate the residence times of the material in the zones, the distribution of the times over the zones, and the mean residence time of the material in the mixer. The results obtained differed by not more than 5% from calculated values.« less