Sizing of Hydrate Storage Shed with Major Facilities for Alumina Refinery

Hi Friends,

In present post, we will discuss the methodology to arrive at the capacity and indicative dimensions of Hydrate storage shed required for a typical Alumina refinery for storage of washed hydrate to take care of any eventualities like sudden outage of Calciner for refractory failure or break down of any other major equipment in calcination section. The basic assumptions and calculations are outlined below-


Annual capacity of Alumina refinery =1000,000 tpa,
Net operating days for refinery = 336 days per year,
Moisture in washed and filtered hydrate = 6% max.,
Bulk density of washed and filtered hydrate = 1.0 t/m3,
Minimum storage capacity of Hydrate storage shed = 7 days of normal plant operation,
Design margin = 15%,
Storage capacity of Hydrate storage shed = 30,000 tonnes hydrate (say),
The angle of repose for dry hydrate varies from 33 to 35 degree,
Thus volumetric capacity of storage shed = 30,000 x 3 = 90,000 cubic meter,
Let  the material height in storage shed below conveyor = 10 meter,
If we take the width of storage shed = 60 meters,
Then length of storage shed = 90,000 / (10 x 60) = 150 meters.
Therefore, the size of Hydrate storage shed works out to 150 m x 60 m.


As such, there are two methods for reclaiming the hydrate from storage shed for feeding to calciner-

• Dry hydrate reclaimed using reversible belt conveyor system for direct feeding to calciner through feed hopper,
• Hydrate is reclaimed by making slurry with water and pumped to horizontal rotary disc table filter (Table filter or Pan Filter) for  filtration and there after feeding to calciners.

Major facilities required for transfer of washed hydrate to storage shed and recovery of hydrate from storage shed back to hydrate filters for feeding to calciners using 2nd method described above are tabulated below-

1. Belt conveyor from table filter to stockpile,
2. Mobile tripper conveyor for hydrate stacking,
3. Hopper for hydrate reclaiming,
4. Hydrate slurry tank with agitator,
5. Belt conveyor from hopper bottom to Hydrate slurry tank,
6. Hydrate slurry pump for pumping slurry to table filter for filtration.

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Thanks and regards.

Kunwar Rajendra