It is desired to use a rotary vacuum filter to separate slurry containing 20 kg of water per kilogram of solid material. Tests on the rotary filter at the conditions to be used for the filtration have indicated that the dimensionless ratio α/β' is 0.6 and 19 kg of filtrate (not including wash water) is obtained for each 24.2 kg of slurry. The temperature and pressure of the surroundings are 25oC and 1 atm, respectively. The pressure drop to be maintained by the vacuum pump is 56 kPa. The fraction of the drum area submerged in the slurry is 0.3 and the fraction of the drum area available for suction is 0.1. On the basis of the following assumptions, estimate the kilowatt rating of the motor necessary to operate the vacuum pump if the filter handles 19000 kg/h of slurry. Assumptions are as follows: Resistance of the filter medium is negligible. Effects of air leakage are included in the value given for α/β'. The value of β' is based on the temperature and pressure of the ambient air. The filter removes all the solids from the slurry. The vacuum pump operates isentropically with an overall efficiency of 50 percent for the pump and motor. The ratio of Cp/Cv remains constant at a value of 1.4
It is desired to use a rotary vacuum filter to separate slurry containing 20 kg of water per kilogram of solid material. Tests on the rotary filter at the conditions to be used for the filtration have indicated that the dimensionless ratio α/β' is 0.6 and 19 kg of filtrate (not including wash water) is obtained for each 24.2 kg of slurry. The temperature and pressure of the surroundings are 25oC and 1 atm, respectively. The pressure drop to be maintained by the vacuum pump is 56 kPa. The fraction of the drum area submerged in the slurry is 0.3 and the fraction of the drum area available for suction is 0.1. On the basis of the following assumptions, estimate the kilowatt rating of the motor necessary to operate the vacuum pump if the filter handles 19000 kg/h of slurry.
Assumptions are as follows:
Resistance of the filter medium is negligible.
Effects of air leakage are included in the value given for α/β'. The value of β' is based on the temperature and pressure of the ambient air.
The filter removes all the solids from the slurry.
The vacuum pump operates isentropically with an overall efficiency of 50 percent for the pump and motor.
The ratio of Cp/Cv remains constant at a value of 1.4
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