Vertical Raw Mill Heat Balance - Solution

Loesche - Heat Balance Calculation Composition %

Moisture %

Limestone

40

4

5.63

Marl

50

6

11.06

Sand

7

10

2.67

Iron ore

3

7

Total

0.78

100

20.14 t/h

Mill output

379.86 t/h

Feed

400 t/h

Moisture on finish product

0.5 %

Gas Flow Balance Inputs

Outputs Amount (t/h)

Mill inlet gas flow Water from feed Water injection False air TOTAL

20.14 5

Nm3/h 330000 25176 6250 31147 392572

% 84.1 Mill outlet gas flow 6.4 1.6 7.9 100

In a vertical roller mill the % of false air is usely between 5 and 10% 330000 Nm3/h on wet Gas coming from the kiln 270°C 307230 Nm3/h on dry % th/h CO2 26.1 9687 O2 6.77 1812 CO 0.1 26 N2 67.2 17363 H20 6.9 2250 100.17 31137

Gas temperature CO2 O2 CO N2 H20

Nm3/h 392572

392572

100°C % 23.07 8.39 0.06 68.53 11.8 100.05

Heat balance Inputs t/h or Nm3/h Hot gases from kiln Mill feed Water from feed Water injection False air Kiln dust Table motor energy TOTAL

330000 379.86 25176 6250 31147 21

T° (°C) 270 20 20 10 25 270

kCal/Nm3 or kCal/kg 3.9 7 3.5 7.7 55

th/h

th/toutput 31137 1481 176 22 240 1155 2353 36565

81.97 3.9 0.5 0.1 0.63 3.0 6.2 96.3

% 100

100

392572 Nm3/h on wet 346248.854 Nm3/h on dry th/h 3363 909 6 7261 1654 13193

17944

17496

-2.496

Outputs % 85.2 4.1 0.5 0.1 0.7 3.2 6.4 100.0

t/h or Nm3/h Gases Kiln dust Kiln feed Water vaporisation Convexion + radiation

T° (°C)

kCal/Nm3 or kCal/kg

392572 21

100 90

380 25.14

90

16.7 18.5 636

TOTAL Difference

th/h

th/toutput

13193 351

34.7 0.9

7027 15989 702

18.5 42.1 1.8

37263

98.1

2%

% 35.4 0.9 18.9 42.9 1.9 100.0