摘要 |
In a process for processing particulate material with a stream of fluid in an annular processing zone, which includes the steps of supplying the particulate material for processing in the zone, discharging processed material from the zone and generating in the zone a circumferentially directed flow of fluid to develop a circulating turbulent band of particles, an improvement to the processing zone which provides a predictable particle flow path both circumferentially and helically of the zone. The improvement comprises directing the flow of fluid to develop a circulating bed with inner bed depth and outer bed depth, a flow of fluid directed at an angle relative to the processing zone base and controlling fluid velocity so that it is greater than the terminal velocity of larger particles point of impact on the bed base and less than the terminal velocity of smaller particles in the superficial space above the bed upper surface.
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