separators

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Separators in the cement industry

Static separators:

3.1

Introduction:

The static separator is like the cyclone a simple mechanical device commonly used in the grinding circuits to remove

relatively large particles from gas streams.

Static separators are relatively inexpensive since they have no moving parts and they are easy to operate.

Static separators (or grit separators) are used especially in the raw mill circuits:

3.2

Advantages of static separators:

Low capital cost

Ability to operate at high temperatures and pressures

Low maintenance requirements because no moving parts

3.3

Main disadvantage of static separators:

Low efficiency especially for very small particles

3.4

Principle of operation:

The material enters with the air stream at the bottom of the separator.

A vortex is created in the upper part of the cone of the separator because of the blades.

The coarse material goes towards the walls because of the centrifugal force, slides to the bottom and leaves the separator.

The fine material exits through the top of the immersion tube.

The fineness of the product is adjusted by changing the position of the blades.

When the blades are in radial position (maximum of opening), the product of the static separator will be coarser.

When the blades are adjusted in a more tangential position, the product is finer because the tangential velocity of the

particle increased and the cut size decreased.

When the adjustment is higher than 60-70°, the particles tangential velocity decreases due to friction against the blades,

and the cut size goes up again.

Click on the picture to enlarge

3.5

Mechanical parts:

Conical section

Adjustable blades (with external adjustment)

Tails cone

Immersion tube (fines outlet)

3.6

Operating characteristics:

Pressure drop usually around 150 mmH2O

Shortening the immersion tube will give a coarser product

Lengthening the immersion tube will give a finer product

Leaving the blades in completely radial position will give a coarse product

Adjusting the blades more tangentially will give a finer product and a higher pressure drop

If the product is not coarse enough, it is also possible to remove blades (1 of 2 for example)

Usual dust concentrations: 500-1000 gr/m3

3.7

Diameter calculation:

The diameter of the separator can be determined with the following formula:

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V-Separators

4.1

Introduction:

This separator is from KHD Humboldt Wedag AG.

The V-separator is generally used with a pregrinding system (Roller Press).

Applications mainly for raw meals, clinker and slag.

The main objective of this separator is to remove a maximum of fines particles from the Roller Press feed in order

to decrease the problems of vibrations.

The V-separator is also combined with the high-efficiency Sepmaster to give the VSK separator. This combination

can be used (for example) for slag, the Roller Press being a finishing system.

4.2

Principle of operation:

As its name suggests, the V-separator V has a V-shaped.

The material enters by the top and falls on a series of inclined plates.

The largest particles fall by gravity and leave the separator at the bottom .

Intake air feed in the separator on one side and sweep the fine particles from the material cascading.

The separation zone is therefore between the inclined plates and a series of deflectors inclined in another direction.

The fines go out with the air to the other side. See the design below:

Click on the picture to enlarge

4.3

Mechanical parts:

Body

Inclined plates

Inclined deflectors

4.4

Operating characteristics:

In case of hot material (clinker), a significant cooling is possible.

At the contrary, in case of humid material (raw meal), a significant drying is possible.

The cut size (or fineness of the product) of the V-separator is controlled only by the airflow quantity.

Pressure drop usually between 50 and 150 mmH2O

4.5

Dimensioning parameters:

Specific feed loading: 4 kg/m3 (of air flow)

Separator air loading by m2 of separating area: 6 m3/sec

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