May a porous plate in a fluidised bed gasifier be responsible for segregation ? when changing a plate, from a perforated to a porous plate, is the pressure difference the impacting factor or simply the size of bubbles, assuming that the total air flow through the distributor has to stay constant
Hello Lydia
Could you be more precise about your fluidized bed: you mention bubbles so we think of a liquid above the porous media but you also mention a gasifier. In that case it is a solid.
Best regards
Good morning! Thank you for your interest! Yes i was not precise. It is quartz sand or olivine in the bubbling fluidized bed. Bubbles form as a consequence of the increasing gas fluidization velocity, so we keep fluidization as smooth as possible but the bubble size depends on the gas distributor .
Hello Lydia
In fact between a porous plate and a grid there is theoretically no difference in the fluidized sand after a sufficient distance from the plate or the grid.
Except that the grid offer no pressure drop and the fluid repartition is more dependant on the pressure drop in the fluidised bed. So with a grid you can have big bubbles crossing the fluidized bed when you start to operate and stabilisation depends on your bed.
The pressure drop in a porous plate gives a better repartition.
I think you have to compare the pressure drop of your bed and the pressure drop of a porous plate or a grid.
Try a small size experiment with a transparent wall.
Thank you! I was planning to do so, i have a small transparent "cold flow" plexiglas bed for trying out. I was only wondering if worth purchasing a rather costly porous plate but i will do so.
best regards
Lydia
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