Continuous Clarification Tank Working principle in a palm oil mill
A= Skimmer height
B= Height of oil layer
C = Height of Sludge
D = Height of some oil + Sludge
Density of Palm Oil is 0.9
Density of sludge is 1.0 (Same as water)
Forces are always equal and opposite if there is no movement. (Newton’s Law)
Weight of SLUDGE = Volume of sludge x density of sludge
Weight of SLUDGE = surface area x height x density of sludge
Weight of SLUDGE = π d2/4 x D x 1.0
Weight of SLUDGE + Oil = surface area x height x density of sludge + surface area (oil) x height x density of oil
=π d2/4 x B x 0.9+ π d2/4 x C x 1.0
Therefore
π d2/4 x D x 1.0 = π d2/4 x B x 0.9+ π d2/4 x C x 1.0
To solve the above equation.
Divide both sides by π d2/
D = 0.9B + C …………………..Equation 1
A+D = B+C
Assume A = 10
Therefore
10+D=B+C
C = 10 + D – B ……………………2
Substitution equation 2 into 1
D = 0.9B + ( 10 + D – B)
D= 0.9B + 10 + D – B
Subtract D from both sides
0 = 0.9B + 10 – B
0 = 0.1B + 10
0.1B = 10 + 0
B = 10/0.1
B= 100
If A = 10 Then B= 100
Therefore the height of the oil in a balanced tank is 10 times the skimmer height.
During mill operations the skimmer heignt can be adjusted to achieve different thickness of oil layer.
For more information about this operation – read article on clarification station operations
