Basic Technical Data Required for Process Design Calculations

Hi Friends,

In present post, we will discuss a few important data which are essentially required for carrying out process design calculations including material balance, thermal energy balance and sizing calculations for various pipelines of Alumina refinery.

1.     Alumina means Al₂O₃ having molar mass = 2x27+3x16=102 g per mole.

2.  Hydrate alumina means Al₂O₃.3H₂O having molar mass= 102+3x18=156 g per mole.

3.  Thus 156 tonnes of Hydrate alumina = 102 tonnes of Alumina, this implies 1 tonne of Hydrate is equal to 102/156 = 0.65385 tonne of alumina.

4.     Specific gravity of dry hydrate = 2.42

5.     Specific gravity of dry Bauxite = 2.55 to 2.80

6.     Bulk density of alumina = 0.95 to 1.05 tonne per m³.

7.     Molar mass of Na₂O = 62 gm/mole ;

8.     Bulk Density of Bauxite = 1.20 - 1.30 t/m³.

9.     Molar mass of Na₂CO₃ =106 gm/mole;

10. Static Angle of Repose of Bauxite = 30 to 32 degree

11. Dynamic angle of repose of Bauxite = 19 to 20 degree

12. Molar mass of Na₂O = 62 gm/mole

13. Bulk Density of Bauxite = 1.20 - 1.30 t/m³

14. Molar mass of Na₂CO₃ = 106 gm/mole

15. Molar mass of NaOH = 40 gm/mole

16. Hardness of Bauxite = 2.5 to 3.0 Moh

17. Bond Index = 10.5 t0 18 kW/st

18. Specific Gravity of dry redmud = 2.30

19. Velocity of slurry in pipe line = 1.5 to 2.44 m/sec.

20. Design velocity of steam in pipeline = 20 to 40 metres per sec.

21. Water requirement  = 135 litres / capita.day

22. Sewage generation rate = 96 litres/capita.day.

23. Solid waste generation = 0.90 kg/ capita.day

24. Stack Height (in metres) = 14x (Q)^0.3;where Q=Emission rate of SO₂ in kg/hr.

25. Total water for Alumina Plant = 6.5 m³/tonne alumina

26. Norms for Green belt = 25% of total plant area (min.)

27. Residue Factor is the ratio of sum total oxides in Bauxite to sum total oxides in residue (red mud) which gives tonnes of residue generated per tonne of Bauxite processed. Residue generation rate with respect to alumina production varies from 1.10 - 1.35 tonnes residue per tonne of alumina. Higher residue factor signifies either poor quality of bauxite or lower alumina recovery or both.

Hope, all major input data have been covered here. It will be our pleasure to receive your valuable remarks / suggestins / comments, if any.

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Thanks and regards.

Kunwar Rajendra