(a) Spherical particles are going to be purified by filtration. The filtering area is 0.05 m2 and filtration is carried out at a constant pressure condition in the presence of a filter cloth of 3 mm thickness. The vacuum pressure applied is 30 kN m2. In the first 400 s, 250 cm3 filtrate is collected. After a further 400 s, an additional 180 cm3 filtrate is collected. Assume the cake to be incompressible, calculate the thickness of the cake being collected associated with this whole operation. [50 marks] (b) An oil with a density of 800 kg m and viscosity of 5 mns m2 passes vertically upwards through a packed bed being filled using the above filtered spherical particles (diameter 1 mm and density 4000 kg m). The height of the packed bed is 100 cm, and the voidage of the packed bed is 0.4. (i) Calculate the mass flow rate per unit area of the bed (G) that fluidisation occurs and the pressure drop of the bed. (ii) Calculate the mass flow rate per unit area of bed (G) at which particle transport takes place (where the fluid velocity reaches the terminal velocity). Also calculate the Reynold number of the particles