Beater Wheel Mill

February 2003

Beater Wheel Mills Mechthild Angleys ALSTOM Power Boiler GMBH, Stuttgart Tel.: +49 711 917 1441

Comments to the attached slides 1. Lignite fired boiler 800 MW 2. Mill and firing arrangement with beater wheel mill 3. Typical view of a beater wheel mill during maintenance 4.Components of a beater wheel mill 5. Beater wheel mill with separating classifier, which divides the pulverised coal stream into a lean and a rich fraction to the burners 6. Beater wheel mill with precrusher 7. View of a mill from the mill door side 8. View cut of a beater wheel mill with percrusher and without classifier 9. 3 dimensional drawing of a mill door 10. Box type classifier 11. Beater wheel 12.Wear part replacment of a beater wheel double bearing 036 158p

Types of Brown Coal/Lignites

Water Coal type

Country

Structure %

Germany/Australia/ Soft brown coal India/Greece Turkey/Bulgaria

Homogeneous earthy, without visible wood structure

LCV MJ/kg

Vol. (waf) %

45 - 70 2 - 20

3 - 12 50 - 65

inhomogeneous earthy and fibrous, with visible 40 - 50 5 - 30 wood structure

5 - 12 45 - 55

Lignite

Yugoslavia/Poland/ Hungary/Austria/ Greece/Germany

Hard lignite

China/Turkey/ earthy, hard, Yugoslavia/Thailand/ shelly USSR/USA

001 328p

Ash (raw) %

10 - 40 5 - 40

6 - 20 40 - 50

Power Station Schwarze Pumpe + 16 1,5 m

± 011 283p

0,0 m

Mill Arrangement and Beater Wheel Mill with Pulverized Coal Firing Mill 5

Mill 4

Mill 7

Mill 3

Mill 8

Mill 2

031 248p

Mill 6

Mill 1

Pulverized Brown Coal Firing Core air Cooling air

Upper air

Pulverized coal Intermediate air

Oil burner

Flue gas resuction duct

Pulverized coal Lower air Ceramic nozzle

Pulverized coal duct

Raw coal chute

Pulverized coal duct

Beater wheel mill

031 010p

Size and Capacities of ALSTOM Beater Wheel Mills (General View)

Mill type

N

26

60

80

120

170

270

340

400

Rated throughput

t/h

11

30

40

60

85

135

170

200

Motor rating

kW 120

280

380

460

650

1035

1400

1600

The rated throughputs refers to the grinding of Rhenish raw brown coal with 60 % moisture at 50 % residue on the 0.09 mm sieve, a mixture temperature of 120 °C in the mill outlet and direct p.f. injection by jet burners of ALSTOM design 035 142p

Beater Wheel Mills Type S and Type N

Type S 035 138p

Type N

Beater Wheel Mill N 340.43 with Separator/Classifier

035 246p

Comminution Process of Beater Wheel Mill Comminution process inside a beater wheel mill:

Mill outlet

035 247p

1

- Crack of particles by flash drying in the hot gas duct

2

- Comminution by impact between beater plates and particle

Beater Wheel Mill N 340.43 with Beater Wheel Transporter

035 238p_quer

ALSTOM Beater Wheel Mill Type N 400.42 1 Connection for flue gas resuction duct 2 Isolating slide damper for flue gas resuction duct 3 Mill door 4 Mill housing 5 Beater wheel 6 Classifier 7 Coarse particle return duct 8 Double bearing 9 Variable speed gear 10 Drive motor 035 132p

Beater Wheel Mill

035 103p

ALSTOM Beater Wheel Mill Type N 340.43 with Separating Classifier

+ 15 .90 m

1 Se pa ra tor/ Cla ssifie r da m pe r

3 Exte nde d course pa rticle re turn duct

2 Distributor in coa l inle t chute

4 Te m pe ra ture m e a surin g point be fore mill

2

1

+

3

8 .43 m 4

± 035 231p

0 .00 m

Beater Wheel Mill with Precrushers

035 243p

Beater Wheel Mill with Prebeater

035 230p

Beater Wheel Mill with Pre-Beater Stage

035 001p

Beater Wheel Mill Mill Door with Prebeater

Beater Wheel Mill Classifier

Beater Wheel Mill Beater Wheel

Beater Wheel Mill Beater Wheel

Beater Wheel Mill Double Bearing