Contents

# tool to calculate Vertical Mill heat balance by Loesche

 Loesche – Heat Balance Calculation Fill in white cells Composition % Moisture % Limestone 40 4 5.63 Marl 50 6 11.06 Sand 7 10 2.67 Iron ore 3 7 0.78 Total 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) Nm3/h % Nm3/h % Mill inlet gas flow 330000 84.1 Mill outlet gas flow 392572 100 Water from feed 20.14 25176 6.4 Water injection 5 6250 1.6 False air 31147 7.9 TOTAL 392572 100 392572 100 In a vertical roller mill the % of false air is usely between 5 and 10% 330000 Nm3/h on wet 392572 Nm3/h on wet Gas coming from the kiln 270°C 307230 Nm3/h on dry Gas temperature 100°C 346248.854 Nm3/h on dry % th/h % th/h CO2 26.1 9687 CO2 23.07 3363 O2 6.77 1812 O2 8.39 909 CO 0.1 26 CO 0.06 6 N2 67.2 17363 N2 68.53 7261 H20 6.9 2250 H20 11.8 1654 100.17 31137 100.05 13193 17944 17496 -2.496 Heat balance Inputs Outputs t/h or Nm3/h T° (°C) kCal/Nm3 th/h th/toutput % t/h or Nm3/h T° (°C) kCal/Nm3 th/h th/toutput % or kCal/kg or kCal/kg Hot gases from kiln 330000 270 31137 81.97 85.2 Gases 392572 100 13193 34.7 35.4 Mill feed 379.86 20 3.9 1481 3.9 4.1 Kiln dust 21 90 16.7 351 0.9 0.9 Water from feed 25176 20 7 176 0.5 0.5 Water injection 6250 10 3.5 22 0.1 0.1 Kiln feed 380 90 18.5 7027 18.5 18.9 False air 31147 25 7.7 240 0.63 0.7 Water vaporisation 25.14 636 15989 42.1 42.9 Kiln dust 21 270 55 1155 3.0 3.2 Convexion + radiation 702 1.8 1.9 Table motor energy 2353 6.2 6.4 TOTAL 36565 96.3 100.0 TOTAL 37263 98.1 100.0 Difference 2 %