2. Separation of solids from liquid is an important process in many chemical industries. This project question is also based on separation of very fine particles from liquid in a long pipe. As shown in a schematic figure below, particles enter the pipe and try to settle under influence of gravity and drag.

Consider a flow of water (density = 1000 kg/m3 , viscosity = 1 cP) in a straight pipe (diameter = 1 m) as shown in the figure below.

The water has suspended particulate matters (predominantly sand with density = 2500 kg/m3 ).

a) For a water-sand flowrate of 1500 m3 /hr with 1000 ppm of sand, calculate sand particle size than can be settled in the tank. (Water: density = 1000 kg/m3 , viscosity = 1 cP; Sand: density = 2500 kg/m3 ).

b) Consider settling of sand particles with different diameters (50, 100, 200, 300 m), calculate the required tank diameter for settling of each particle size at a constant inlet flow rate of 1500 m3 /hr.

c) Now consider settling of 50 m size particles in the tank with diameter of 10 m and height of 10 m, calculate inlet flow rate required.

d) For fine particles ( 50 m), if tank size required to operate at 1500 m3 /hr is very large, suggest design modification to settle the fine particles.

2. Separation of solids from liquid is an important process in many chemical industries. This project question is also based on separation of very fine particles from liquid in a long pipe. As shown in a schematic figure below, particles enter the pipe and try to settle under influence of gravity and drag. Consider a flow of water (density = 1000 kg/m, viscosity = 1 CP) in a straight pipe (diameter = 1 m) as shown in the figure below. The water has suspended particulate matters (predominantly sand with density = 2500 kg/m). Inlet Outlet Areas where particles tend to settle a) For a water-sand flowrate of 1500 m/hr with 1000 ppm of sand, calculate sand particle size than can be settled in the tank. (Water: density = 1000 kg/m3, viscosity = 1 cP; Sand: density = 2500 kg/m). (30 marks) b) Consider settling of sand particles with different diameters (50, 100, 200, 300 um), calculate the required tank diameter for settling of each particle size at a constant inlet flow rate of 1500 m/hr. (20 marks) c) Now consider settling of 50 um size particles in the tank with diameter of 10 m and height of 10 m, calculate inlet flow rate required. (4 marks) d) For fine particles (s 50 um), if tank size required to operate at 1500 m/hr is very large, suggest design modification to settle the fine particles. (6 marks)