PARTICLE TECHNOLOGY Flashcards
In operating a batch filter, which of the following is the correct method of operation?
A. The particles forming the cake should be large.
B. The slower the flowrate, the more efficient the recovery.
C. Keeping the pressure constant, the rate of flow increases.
D. Keeping the flowrate constant and gradually increase the pressure.
Keeping the flowrate constant and gradually increase the pressure.
Relation of 1/k and 2Ve/k to A
1/k is directly proportional to the 1/A^2
2Ve/k is directly proportional to 1/A
Relationship of 1/k and 2Ve/k to delta P
1/k is directly proportional to the 1/delta P
2Ve/k is directly proportional to 1/delta P
This is used as a precoat on the filter media or mixed to the slurry to increase the porosity of the cake.
Filter aids
Examples of filter aids
diatomaceous silica
perlite
purified wood cellulose
Batch filtration vs Continuous filtration
Batch-small capacity (PFFP,LEAF)
CONTINUOUS- LARGE CAPACITY (CONTINUOUS ROTARY FILTER)
Driving force of filtration
gravity, pressure/vacuum
The porosity of compressible cake is
a. minimum at the filter medium
b. minimum at the upstream face
c. maximum at the filter medium
d. same throughout the thickness
a. minimum at the filter medium
It is the barrier that lets the liquid pass while retaining most of the solids
filter medium or septum
T OR F
Increase in feed solids concentrationis generally an effective means of increasing solids filtration rate, and thereby minimizing cake moisture content.
T
These chemicals are used for pretreatment of slurries to provide acceptable filtration rate.
Flocculating agent
Random motion imparted to the partile by collisions between molecules of the fluid surrounding the particle.
Brownian motion
Devices used for the separation of solids particles into several fractions based on their rate of settling through a medium
Classifiers
Devices used for the separation of solids particles into several fractions based on their settling velocity in a medium
Classification
The operation by which solids are separated from liquids due to difference in the respective densities
sedimentation
forces acting on a particle in fluid are
external force, buoyant force, drag force
It is defined as the force exerted by the fluid on a particle in the opposite to the direction of flow of the particle
drag force
the terminal velocity of a small sphere settling in a viscous fluid varies as the
a. first power of its diameter
b. inverse of the fluid viscosity
c. inverse square of the diameter
d. square of the difference in specific weights of solid and fluid
b. inverse of the fluid viscosity
buoyant force
a. for non-symmetrical bodies is not vertical
b. a fluctuating velocity
c. depends on the weight of the floating body
d. none of these
c. depends on the weight of the floating body
terminal velocity is
a. constant velocity with a=0
b. a fluctuating velocity
c. attained after moving one-hald of total distance
d. none of these
a. constant velocity with a=0
in hindered settlinb, particles are
near each other
moisture can be removed from lubricating oil using
a. tubular centrifuge
b. clarifier
c. sparkle filter
d. vacuum leaf filter
a. tubular centrifuge
milk cream separator
a. disc bond centrifuge
b. sharpless supercentrifuge
c. batch basket centrifuge
d. sparkler filter
a. disc bond centrifuge
most effectively used for clarification of lube oil and printing ink
a. sparkler filter
b. precoat filter
c. disc bowl centrifuge
d. sharpless supercentrifuge
d. sharpless supercentrifuge
It is used to grind wheat and rye to flour and corn
roller mills
Used to produce potator flour, tapioca and other flours
hammer mills
It is mainly used for crushing hard materials and are usually followed by other crushers
jaw crusher
is the temperature attained when large amount of water is contacted with the entering gas
adiabatic saturation tempetrature
what is adiabatic saturation line?
adiabatic humidification line
Steady state temperature reached by a small amount of liquid evaporating into large amount of unsaturated vapor gas mixture
Wet bulb
