Packed Bed and Fluidized Bed Flashcards
(16 cards)
With increasing gas velocity, a point is reached where the drag force imparted by the upward moving gas equals the weight of the particles and the voidage of the bed increases slightly.
minimum fluidization
Force of pressure = ?
gravitational force
Increasing the gas flow further, the formation of fluidization bubbles sets in
bubbling regime
empty cross section of the tower (superficial velocity)
minimum fluidization
if fluid velocity is increased, pressure drop also increases. this is proven by?
ergun equation
porosity of bed when the fluidization occurs
minimum porosity for fluidization
Fluid (Liquid/Gas) passed at a very low velocity through a packed bed of particles, the particles remain?
stationary
When the flow of a gas passed through a bed of particles is increased continually, a few
vibrate, but still within the same height as the bed at rest
fixed bed
The upper surface of the bed disappears and instead of bubbles, one observes a turbulent motion of solid clusters and voids of gas of various sizes and shapes
turbulent regime
If the particles are fluidized at a high enough gas flow rate, the velocity exceeds the terminal
velocity of the particles
turbulent regime
When particles begin to move
onset of fluidization or minimum fluidization
Fluid (Liquid/Gas) passed at a very ___________________ through a packed bed of particles, the particles remain stationary
low velocity
If the ratio of the height to the diameter of the bed is high enough, the size of bubbles may become almost the same as diameter of the bed
slugging regime
empty cross section of the tower
superficial velocity
the process where fluid (Liquid/Gas) passed at a very low velocity through a packed bed of particles, the particles remain stationary.
fluidization
the lower-velocity fast fluidized-bed regime and the higher velocity transport regime often called the
pneumatic transport regime
