Particle Technology - Sedimentation

Front

What is the mechanism of filtration?

Back

In filtration, solid particles are removed from a slurry by forcing the fluid through a filter medium, which blocks the passage of the solid particles and allows the filtrate to pass through.

Front

What is sedimentation?

Back

In settling and sedimentation, particles are separated from the fluid by gravitational forces acting on the particles.

Front

What are the forces acting on a rigid particle in a fluid?

Back

1. Gravitational force (Fg = mg) 2. Buoyant force (Fb = Vp * ρf * g) 3. Drag force (FD = CD * (u^2) * (ρ * A) / 2)

Front

What is terminal velocity (VT) in sedimentation?

Back

Terminal velocity is the constant velocity that a particle quickly reaches, which is the maximum attainable settling velocity under the given circumstances.

Front

What is Stoke's Law for drag coefficient?

Back

In the laminar flow region (Re < 1), the drag coefficient can be predicted by Stoke’s law: CD = 24/Re.

Front

What is Brownian motion?

Back

Random motion imparted to the particle by collisions between the molecules of fluid surrounding the particle, which tends to suppress the effect of gravity.

Front

What is hindered settling?

Back

Hindered settling occurs when large numbers of particles are present in the fluid, affecting the velocity gradient of the particles due to their close presence.

Front

What is the principle of sedimentation?

Back

Larger particles settle first in a liquid at a rate that is different from that of smaller ones due to their greater mass.

Front

What are the four zones of a sedimentation basin?

Back

1. Inlet Zone 2. Settling Zone 3. Sludge Zone 4. Outlet Zone.

Front

What is the purpose of a clarifier?

Back

To remove solid particles or suspended solids from a liquid through gravity sedimentation.