(Solved): Q9:- Filtration - is carried out in -a plate and frame = filter press, with 20 frames 0.3m squar ...

Q9:- Filtration - is carried out in -a plate and frame = filter press, with 20 frames $0.3\mathrm{m}$ square and $50\mathrm{mm}$ thick, and the rate of filtration is maintained constant for the first 300 s...During this period, the pressure is-raised to $350\mathrm{KPa}$, and one-quarter of the total filter per cycle is obtained. At the end of the constant rate period, filtration is continued at a constant prissure of $350\mathrm{kPa}$ for further $1800\mathrm{s}$, after which the fromes are fult: The total volume of filtrate per cycle is $0.7{\mathrm{m}}^3$ and dismanting and refitting of the ress takes $500\mathrm{s}$ It is decided to use a rotary drum filter, $1.5\mathrm{m}$ long and $2.2\mathrm{m}$ in diameter, in place of the filter press. Assuming that the resistance of the cloth is the same in the two plants and that the filter cake is incompressible, calculate the speed of rotation of the drum which will resuit in the same -overall rate of filtration as was obtained with the filter press. The filtration in the rotary filter is carried out at a constant pressure difference of $70\mathrm{kp}$ n and the filter oprates. with $25\%$ of the drum submerged in the slurry at any instant.