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The pressure drop in bubbling fluidised bed ___________ with time for a given flow velocity.

Correct Answer: Oscillates
The pressure drop oscillates with time because the gas inlet is intermittent and the bubbles burst at any moment, hence the pressure drop oscillates.

Parameters that describe the overall behaviour of the fluidized bed in the bubbling regime are: (i) minimum fluidization velocity, (ii) Pressure drop across the bed, (iii) Bed height increase, (iv) Particle elutriation.

Bed pressure drop in an air fluidised bed of catalyst particles (ρp = 200 kg/m3, Dp = 0.05 cm) of 60 cm bed depth and bed porosity of 0.5 expressed in cm of water (manometer) is

A 0.5 m high bed made up of a 1 mm dia glass sphere (density 2500 kg/m3) is to be fluidised by water (density 1000 kg/m3). If at the point of incipient fluidisation, the bed voidage is 40%, the pressure drop across the bed is

A bed of spherical particles (specific gravity 2.5) of uniform size 1500 μm is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun's equation for the above fluid-particle system (in SI units) is given below:
Δ P/L = 375 × 103 VOM + 10.94 × 106 V2OM (SI units)
If water is to be used as the fluidising medium, in actual operation, the above bed has a height = 1 m. What is the porosity of the fluidised bed?

If the operation on a fluidised bed is a dense flowing fixed bed, then which one of the following method is used for pressure drop calculation?

Pressure drop in a fluidised bed reactor is __________ that in a similar packed bed reactor.

The pressure drop in fluidised bed on fluidisation __________ with increasing flow rate.

Applying a pressure drop across a capillary results in a volumetric flow rate 'Q' under laminar flow conditions. The flow rate for the same pressure drop, in a capillary of the same length but half the radius is

A gas (density = 1.5 kg/m3, viscosity = 2 × 10-5 kg/m.s) flowing through a packed bed (particle size = 0.5 cm, porosity = 0.5) at a superficial velocity of 2 m/s causes a pressure drop of 8400 Pa/m. The pressure drop for another gas, with density of 1.5 kg/m3 and viscosity of 3 × 10-5 kg/m.s flowing at 3 m/s will be

After fluidisation, the pressure drop in the fluid phase across the bed is _______ to the bed weight over unit surface of the bed cross section.