preheat process

L\DATA\Dept150\Polysius Presentations and Training\Polysius Training\Pyroprocessing\Preheater\preheat_process.ppt 140 TEI, 140 CD

Krupp Polysius Corp.

Preheater and Calciner

Process Training



CM

The modern kiln plant

Raw mill

Clinker cooler

Calciner

Rotary kiln

Preheater



Preheater



DOPOL 90



Gas and material flow in a preheater



DOPOL 90 B-type cyclone

1

2

3

4

5

1 Cyclone 2 Intermediate piece3 Dip pipe4 Gas duct 5 Meal chute



Calciner cyclone

System cyclone

DOPOL® 90

Dedusting cyclone

Cyclone types



CM

The modern kiln plant

Raw mill

Clinker cooler

Calciner

Rotary kiln

Preheater



DOPOL 90 - preheater design



Number of cyclone 4 5 6Exhaust gas

- temperature °C 370 315 280

- volume Nm³/kg clinker 1,372 1,353 1,345

- dust relative to clinker % 8 6,5 5

- pressure loss mbar 33 38 45

Fuel consumption kcal/kg clinker 740 718 705

Cooler efficiency % 74,6 73,1 72,1

Clinker temperature °C 100 100 100

Cooling air Nm³/kg clinker 1,7 1,7 1,7

Cooler vent air

- volume Nm³/kg clinker 0,84 0,87 0,88

- temperature °C 295 305 312

Electrical power consumption

- for exhaust gas fan kWh/t clinker 5,6 5,7 6,1

- for total kiln plant kWh/t clinker 15,1 15,2 15,7

Permitted RM moisture

- exhaust gas only (with coal mill) % 7,6 5,6 4,3

- exhaust gas only % 8,5 6,5 5,3

- exhaust gas with exhaust air % 11 9,5 8,7

Technical data



Drying capacities - preheater systems

AS 6 AS 5 AS 4 AS 3 AS 2

700 750 800 850 9000

100

200

300

400

500

600

0

4

8

12

16

20

24

Fuel consumption [ kcal/kg cli ]

Exh

aust

gas

tem

p. [

°C

]

Dry

ing

cap

acit

y [

% -

H2O

]

PH exhaust only -->

PH + cooler exhaust-->

<-- PH exhaust temp.



Calciner



PREPOL AS PREPOL MSCPREPOL AS-CC PREPOL MSC-CC

Calciner types



PREPOL AT



TA-duct

Fuel injection

Calciner loop

PREPOL AS



PREPOL AS-CC

TA-duct

Calciner loop

Combustion chamber



CC-Chamber outlet(Connection tothe calciner)

Tertiary duct

Tangential inlet fortertiary air inlet

Central inlet for tertiary air

Burner

Meal inlet

Meal inlet

Tangential inlet fortertiary air inlet

Combustion - Chamber (CC)



PREPOL MSC

Kiln inlet burner

PC - burner

Meal stagingTertiary air duct

Top air duct

Deflection chamber



PREPOL MSC-CC

Kiln inlet burner

PC - burner

Deflection chamber

Top air duct

Tertiary air duct



Tertiary air duct



MSC Calciner with Tire Feed Chute



Tertiary air from cooler

w < 8 m/s w < 6 m/s

w > 26 m/s

w < 8 m/s



w < 5 m/sw < 5 m/s

w > 26 m/s

Tertiary air from kiln hood



kiln hood cooler measures

secondary air temperature lower higher

thermal stress on outlet segments + lower better cooling andform of segments- higher

burn out in the calciner + better - worse

- lower + higher

- higher

- higher + lower

+ lower

CC - Calciner

adapted dimensionnig and quality of refractory

optimized burner adjustment

precalcination rate

- higher + lowerbypass losses

- higher + lowerload of sintering zone

thermal stress on tertiary airflap and refractory

- bigger + smallersize of kiln hood

- longer + shorterlength of burner

(+ lower) (- higher)NOx - formation

Investment cost

Tertiary air connection



“Low-dust” kiln inlet



Fuel type PREPOL AS PREPOL AT

Natural gas < 150000 < 100000

Fuel oil < 180000 < 120000

high reaktive Coal < 130000 < 87000

low reaktive Coal < 90000 < 60000

e.g. Pet Coke < 80000

Thermal calciner loading in kcal/m³/h

Calciner volume loading



Fuel design and distribution



Coal - activity

Time [s]

O2-

conc

entr

atio

n [%

]



NOx - generation in clinker burning process

Calciner: Fuel - NOx - exess air - nitrogen content - reactivity

Sintering zone: Thermal NOx - temperature - exess air - retention time



Stage 2

Stage 3

Stage 4

Stage 1

0,4 - 0,6 Q

Q = total fuel= excess air figure

Fuel

0,4 - 0,6 Q

> 0,1 Q

> 1,05

0,9 < < 1,05

Air 0,9 < < 1,05

Meal

NO

CHi

NHi

CO2H O2N 2CO

NO

CONO

CHi

CO2N 2

NHiH O2

NOH O2N 2 CO2

Combustion conditions for NO reduction by fuel, air and meal staging



NOx and O2 at kiln inlet

O2 at kiln inlet [%]

NO

x at

kiln

inle

t [g

NO

2/kg

cli]



NOx - generation and volatiles

Volatile matter in fuel [%]

NO

x -

gene

ratio

n in

cal

cine

r [N

O2/

kgcl

i]



NOx and Nitrogen in fuel

Nitrogen in fuel [%]

NO

x [N

O2/

kgcl

i]



Nox and calciner temperature

Calciner temperature [ºC]

NO

2 [m

g/N

m3 ]

@ %

O2



Operating results MSC plants

NO

x -

emis

sion

[gN

O2/

kgcl

i]



0

0.5

1

1.5

2

2.5

NO

x -

Em

issi

on

[g

NO

2/kg

Cli]

AS - operation MSC - operation

800 mgNO2/Nm³(10 % O2)

500 mgNO2/Nm³(10 % O2)

32%

53%

35%

28%

30%




NO

x -

emis

sion

[gN

O2/

kgcl

i]




0

0.5

1

1.5

2

2.5N

Ox

- E

mis

sio

n [

gN

O2/

kgK

l]

KI - AS - operationAS - operation

MSC - operation

800 mgNO2/Nm³(10 % O2)

500 mgNO2/Nm³(10 % O2)

32%53%

35%28%

30%

Plant A B C D E

Fuel 80% Pet Coke20 % Coal

Lignite CoalBleeching Earth

Paper wasteFly Ash

CoalTyresPlastic

OilPaper waste

PlasticCarbon Marl

Volatiles in fuel 15 % 45% 27,3 % ~25 % >40 %




Operating results MSC plantsN

Ox

- em

issi

on [

gNO

2/kg

cli]




0

0.5

1

1.5

2

2.5

NO

x -

Em

issi

on

[g

NO

2/kg

Kl]

KI - AS - operationAS - operation

MSC - operation

800 mgNO2/Nm³(10 % O2)

500 mgNO2/Nm³(10 % O2)

32%53%

35%28%

30%

Plant A B C D E

Fuel 80% Pet Coke20 % Coal

Lignite CoalBleeching Earth

Paper wasteFly Ash

CoalTyresPlastic

OilPaper waste

PlasticCarbon Marl

Volatiles in fuel 15 % 45% 27,3 % ~25 % >40 %



NOx - prognosisNOx - emission



CO - prognosis

preheat process

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