separators- types, applications and operation

Separators- Types, applications and operation

Josef KochHTC – Operational Support (Comminution)Cement Production Intense TrainingLeimen, 16 th November 2011

16.11.2011Separators – Types, applications and operation – Josef Koch

Agenda

� Working principle

� Static Separators

� Dynamic separators


Working principle

� Definition of Separation

– Separation of material into a fine and a coarse fraction.

– Separation of solids from gas/liquid

– Ideally with a defined / predictable cut-size

– Not using Sieves / Filters (amount and fineness of material)

– Available forces to perform Separation:

� Gravity

� Air-Stream Drag Force

� Centrifugal Force


Working principle


Wind

Gravity


Working principle

� Conventional separators

Forces acting on the particles

– Aerodynamic forces

– Centrifugal forces

– Gravity


Working principle

� High efficiency separators

Forces acting on the particles

– Aerodynamic forces

– Centrifugal forces

– Gravity


Working principle

� High efficiency separators

Centrifugal force Centrifugal force FFZZ = m x (v= m x (vtt²²/R)/R)

Aerodynamic forceAerodynamic forceFFLL = = CdCd x A x x A x ρρaa x (x (∆∆vvrr²²/2)/2)

GravityGravityFFGG = m x g = m x g

m : particle massvt : tangential speedR : radiusCd : aerodynamic coefficient f(Re)ρa : air densityA : particle section∆vr : vr(air) - vr(particle)


Working principle

� Centrifugal force and gravity force increase with m ass

– increase with d3 (cubic value of diameter)

� Drag force increases with cross section

– increases with d2 (square value of diameter)

� Increase of size impacts more on centrifugal and gr avity forces than on drag force


Agenda





Static Separators

� Cyclone


Static Separators

� Cyclone - Working principle

-Separation of coarser Particles:

Centrifugal Force

-Separation of finer Particles:

Gravity + Centrifugal Force

-Up / Transport:

Air Drag Force by external Fan


� Cyclone

36006,2πnV4

d∗∗∗

∗=&

Rule of thumb for dimensioning

d= nominal diameterV= total airflown= number of cyclones

Static Separators


� Cyclone

1. Operation

- ∆p ≈ 10 – 15 mbar

- Dedust. Efficency ≈ 75 – 80 %- Adjustment to fineness:

� Gas flow

� Diameter immersion pipe� Depth of immersion pipe

2. Applications- Dryers

- Preheater Tower

- Dynamic separators (2nd & 3rd Gen.)

Static Separators


� Grit separator

Static Separators


Static Separators

� Grit separator - Working principle


Centrifugal Force


Gravity + Centrifugal Force

-Up / Transport:

Air Drag Force by external Fan


� Grit separator

V0127,0d &∗=

Rule of thumb for dimensioning

d= nominal diameterV= total airflown= number of cyclones

Static Separators


� Grit separator

1. Operation

- ∆p ≈ 10 – 15 mbar

- Dedust. Efficency ≈ 75 – 80 %- Adjustment to fineness:

� Position of blades

� length immersion pipe

2. Applications

- Vertical Roller mills- Air swept mills

Static Separators


� VS Separator

Static Separators


Static Separators

� VS Separator - Working principle


Gravity


Air drag force

-Up / Transport:

Air drag force


� VS Separator

1. Rule of thumb for dimensioning

- Specific air load: 4 kg/m³

2. Operation� ∆p ≈ 10 – 15 mbar� Dedust. Efficency ≈ 75 – 80 %� Adjustment to fineness:

- Air velocity

3. Applications- Combi grinding plants- Finish grinding plants

Static Separators


Agenda





Dynamic Separators

� 1. Generation


Dynamic Separators

� 1. Generation - Working principle


Gravity


Air drag force

-Transport:

Air drag force & Gravity


� 1. Generation

1. Dimenisioning

- Varying with the suppliers

- Guide values (Cement fineness – spec. Load)� 2500 cm²/g – 2,2 – 3,6 t/h.m²

� 4500 cm²/g – 1,0 – 1,5 t/h.m²

2. Applications

- Fineness range: 3000 – 5000 cm²/g

- Grinding plants

Dynamic Separators


� 1. Generation

1. Adjustment of fineness during operating time

- Increased speed of counterblades

- Reduce air flow rate

2. Adjustment of fineness during stop

- Increased number of counterblades- Increased size of counterblades

- Reduced distance of counterblades

Dynamic Separators


� 1. Generation

1. distribution plate below selecting zone : part of material not selected.

2. airflow : no control, inefficient fan.

3. Poor cycloning effect

4. selection zone :action not constant, very narrow.

5. fineness:narrow range of adjustment.

Dynamic Separators


� 2. Generation

Dynamic Separators


Dynamic Separators



Gravity


Air drag force

-Transport:

Air drag force


� 2. Generation

1. Dimenisioning


- Guide values (Cement fineness – spec. Load)� 3000 cm²/g – 8 t/h.m²

� 4000 cm²/g – 5 t/h.m²

� 5000 cm²/g – 4 t/h.m²

2. Applications

- Fineness range: 3000 – 5000 cm²/g- Grinding plants

Dynamic Separators


� 2. Generation

1. Adjustment of fineness during operating time- Increased speed of counterblades

- Reduce air flow rate

2. Main suppliers- Krupp Fördertechnik- KHD- Krupp Polysius

Dynamic Separators


� 2. Generation

Improvements1. external fan

2. several small cyclones

but1. no improvement in the selecting

zone

2. distribution plate still below

selecting zone

Dynamic Separators


� 3. Generation

Dynamic Separators


Dynamic Separators



Gravity


Air drag force

-Transport:

Air drag force


� 3. Generation

1. Dimenisioning


- Guide values (Cement fineness – spec. Load)� 3000 cm²/g - 10 t/h.m²

2. Applications- Fineness range: 3.000 – 6.000 cm²/g acc. Blaine

- Ball mill Grinding plants (raw, cement)

- Vertical roller mills- Roller Press grinding circuits

Dynamic Separators


� 3. Generation

1. Adjustment of fineness during operating time

- Increased speed of rotary cage- Reduce air flow rate

2. Main suppliers- KHD

- Krupp Polysius

- F.L. Smidth

Dynamic Separators


� 3. Generation

Dynamic Separators

Sepol (Polysius)

QKD (Christian Pfeiffer)

O-SEPA (Fuller)


� 3. Generation

Dynamic Separators

Sepax (F.L. Smidth)

SD (Sturtevant)


� Vertical Mills

Dynamic Separators

LSKS (Loesche)

Sepol (Polysius)

SLS (GPAG)


Agenda





Added bonus

� Effects of modifications in cage and airflow on a high efficiencySeparator

IncreaseAirflow

DecreaseAirflow

IncreaseCage Speed

DecreaseCage Speed

IncreaseAir and

Cage Speed

DecreaseAir and

Cage Speed

Blaine = =

%P 325

CL = =

Caution: These are just general rules of thumb. Actual reactioCaution: These are just general rules of thumb. Actual reactions may differ depending on the casens may differ depending on the case.


for better building…..

Thank You!

separators- types, applications and operation

Documents