# PARTICLE TECHNOLOGY

## Centrifugal separation - Chapter 8

### Explanation of filtering centrifuge modelling

The model used in the online simulation of a filtering centrifuge is explained here:

### Online filtering centrifuge modelling

Online simulation of a filtering centrifuge, you can enter your inputs and the model provides tabular data for the: filtrate volume, dry cake mass, cake radius all with respect to time, and the cake concentration and cake resistance for the given rotational speed chosen.

### Answers to problems:

Q1
i) the correct answer is (c)
ii) the correct answer is (a)
iii) As the acceleration depends on the radial position. In gravity, the acceleration (9.8 m s-2) does not depend on the particles position. However, in a centrifuge position is important - see equation (a) above. So, the acceleration increases as the radial position increases. In order to relate position and time we will, therefore, need to integrate this equation - unlike under gravity settling.
iv) the correct answer is (c)
v) In order to appreciate in which direction the oil drops move, you must think about what would happen under gravity if the drops were within a column of liquid. As they have a density less than water, they will therefore float. Similarly, within a centrifuge surrounded by water - the oil drops will move INWARDS.
the correct answer is (b)
vi) the correct answer is (a).

Q2
i) the correct answer is (b).
ii) the correct answer is (d).
iii) the correct answer is (d).
iv) the correct answer is (a).

Q3
i) the correct answer is (a).
ii) the correct answer is (a).
iii) the correct answer is (c).
iv) the correct answer is (a).

Q4
Remembering that Sigma refers to the plan area of a settling basin that does the same clarification job, see the bottom of page 78, then assuming that there are no other factors different between these machines the answer will be the machine with the highest Sigma value.

Q5

Q8
i) the correct answer is (d).
ii) the correct answer is (b).
iii) the correct answer is (c).
iv) the correct answer is (b).
v) the correct answer is (a).
vi) the correct answer is (b).
vii) the correct answer is (a).

Q9
i) the correct answer is (b).

FAQ

### Centrifuge equipment suppliers

For an up-to-date list of centrifuge equipment suppliers please use the Google link below:
Google search for centrifuge suppliers