Dry out-heating-up-of-cement-kiln-refractories

1. Drying out and Heating up of refractory installations in the cement
industry
Dirk Basten
Refratechnik Cement Supervisor Training Course 2012

2. Refractory installation
of a complete plant

3. static
predominantly castable
dynamic
predominantly bricks
Scheme of the refractory installation of a complete plant
static
predominantly castable

4. Water sources – physically bonded water
Installation of wet bricks Strictly follow guidelines
Avoid leaking water

5. 0
100
200
300
400
500
600
700
800
900
1000
1100
1200
1300
1400
0 12 24 36 48 60 72 84 96 108 120 132 144 156 168
t [h]
T [°C]
approx 13 K/h
approx 10 K/h
approx 30 K/h
approx 10 K/h
TrocknungTrocknungTrocknungTrocknung AufheizenAufheizenAufheizenAufheizen
Anmerkungen: Generell sollte vor dem Beginn der Trocknung und des Aufheizens ein mindestens 24 stündiges Aushärten der Masse stattgefunden haben!
1* > Ofendrehung 180° alle 45 minutes - Referenzmanteltemperatur in der Brennzone ca. 100 - 150°C
2* > Ofendrehung 90° alle 30 minutes - Referenzmanteltemperatur burning zone ca.. 200 - 235°C
3* > Ofendrehung kontinuierlich - Referenzmanteltemperatur burning zone ca. 260 - 310°C
* theoretical calculated shell temperature - depends on environment conditions
1*
2*
3*
Entfernen der
Abdichtungen / Start des
Hauptbrenners
850°C -1000°C
Inbetriebnahme

6. Typical dry out curve for complete new plant

7. Aufheizdiagrammfeuerfester Massen (LCC, MCC, SC, JC)
Heating diagrammof refractory concretes (LCC, MCC, SC, JC)
0
100
200
300
400
500
600
700
800
900
1000
1100
1200
1300
1400
1500
0 10 20 30 40 50 60 70 80 90 100 110
Zeit nach Einbau / h
Time after installation / hrs
Temperatur/°C
Temperature/°C
10 h/ 500 °C
min. 24 hErhärtungsdauer
min. 24 hrs setting time
20 h / 110 - 150 °C
15 °C/h
25 °C/h
30 °C/h
bis zur Einsatztemperatur
up to temp. of application
Heating Up
Drying
Time after installation / hTime after installation / hTime after installation / hTime after installation / h
Heating diagram of refractory concretesHeating diagram of refractory concretesHeating diagram of refractory concretesHeating diagram of refractory concretes
Heating diagram of refractory concretes (AR, LCC, SC, JC, G,Heating diagram of refractory concretes (AR, LCC, SC, JC, G,Heating diagram of refractory concretes (AR, LCC, SC, JC, G,Heating diagram of refractory concretes (AR, LCC, SC, JC, G,
MCG, LCG) Stationary areas wall thickness 50MCG, LCG) Stationary areas wall thickness 50MCG, LCG) Stationary areas wall thickness 50MCG, LCG) Stationary areas wall thickness 50---- 300 mm300 mm300 mm300 mm

8. Behaviour of drying rate
as a function of drying time
0
10
20
30
40
50
60
70
80
90
100
1 2 3 4 5 6 7 8 9 10 11 12 13
Dryiing time
Dryingrate
Drying time [h]Drying time [h]Drying time [h]Drying time [h]
Dryingrate[quantity/h]Dryingrate[quantity/h]Dryingrate[quantity/h]Dryingrate[quantity/h] Drying rate as a function of timeDrying rate as a function of timeDrying rate as a function of timeDrying rate as a function of time
tkn
Phase 1Phase 1Phase 1Phase 1
continous drying
rate
Phase 2Phase 2Phase 2Phase 2
Decreasing drying rate
Low vapour pressure low drying rate

9. Ppore openingPmeniskus >Phase 1:
outletInlet
air
100100100100°°°°CCCC
/1 bar/1 bar/1 bar/1 bar
20202020°°°°CCCC
/0.02 bar/0.02 bar/0.02 bar/0.02 bar
T [°C]
Ppore opening
Pcapillary
Pmeniskus
∆P≈ 1 bar
Low temperatur, continous airstream with high ventilation

10. Ppore opening
Pcapillary
Pmeniscus
T [°C]
OutletInlet Air stream
350350350350°°°°CCCC
/165 bar/165 bar/165 bar/165 bar
100100100100°°°°CCCC
/1 bar/1 bar/1 bar/1 bar
< Ppore openingPMeniskusPhase 2:
∆P≈ 164 bar
High temperature, low ventilation and airstreamHigh temperature, low ventilation and airstreamHigh temperature, low ventilation and airstreamHigh temperature, low ventilation and airstream

11. Pressure- and temperatur gradient in a to be dried refractory body
(Dissertation: Modell zur Beschreibung der Trocknung von Feuerbetonen, Ingo Großwendt, 2007, p.25)
0
50
100
150
200
250
0 50 100 150 200 250 300 350 400
Temperature (°C)Temperature (°C)Temperature (°C)Temperature (°C)
Saturationvapourpressure(bar)Saturationvapourpressure(bar)Saturationvapourpressure(bar)Saturationvapourpressure(bar)
Aufheizdiagrammfeuerfester Massen (LCC, MCC, SC, JC)
Heating diagrammof refractory concretes (LCC, MCC, SC, JC)
0
100
200
300
400
500
600
700
800
900
1000
1100
1200
1300
1400
1500
0 10 20 30 40 50 60 70 80 90 100 110
Zeit nach Einbau / h
Time after installation / hrs
Temperatur/°C
Temperature/°C
10h / 500 °C
min. 24 h Erhärtungsdauer
min. 24 hrssetting time
20 h /110 -150 °C
15°C/h
25°C/h
30°C/h
biszur Einsatztemperatur
upto temp. of application

12. Explosive spalling of castable surface (satellite cooler)

13. Dry out - surface cracking
Typical view on a badly
predried castable , cooler
sidewalls

14. Explosive spalling of Castable

15. Spalling of wet LCC castable on burner

16. Optimized drying schedule

17. Exhaust gas – sealing of kiln and ducts
Protection against humid exhaust gases (filter, basic bricks)

18. Evaporation holes in the cycloneroof
lockable socket for controled evaporation

19. Heating up of kiln

20. Contraction at tyre
Limiting mechanical components

21. Temperaturedistribution in brick and kiln shell during heating up
In 8h to 1000°C

22. Too slowly heating up, too early turning of kiln
Loose lining
migration, relativ
movement

23. Too fast heating up
Axial and radial pressure
Spalling , cobblestone surface

24. Done: Drying and heating successfully finished
first clinker in cooler
Typical timing:
78 h – 120 h