Lime for VCI
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Transcript of Lime for VCI
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Types of chemical processes
eg Quicklime Manufacture
CaCO3(s) CaO(s) + CO2(g)
In this case the feedstock is the raw material -limestone- that needs only be crushed.
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In a batch process the kiln .
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In a batch process the kiln is filled with layersof limestone and fuel....
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In a batch process the kiln is filled with layersof limestone and fuel....
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In a batch process the kiln is filled with layersof limestone and fuel....
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....and the latter is set alight.
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When the reaction is complete and the kiln cool the
contents are removed ready for the next batch.
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Why is this simple process not done on a large scale ?
Cost of labourto fill and empty kiln
Kiln must be allowed to cool wasting energy
Extent of reaction may vary within the kiln.
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In a continuous reactor the limestone is fed intoone end of a heated rotating tube and quicklime
falls out of the other.
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...butratherbigger!
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What are the advantages of this plant?
It may be automated so labour costs are minimised
if decomposition is incomplete it is easy to adjustthe flow rate or temperature to correct this.
BUT
An expensive plant is needed dedicated to
making just one product.
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Continuous reactors are suitable for high tonnageproduction of a single product.
Batch reactors can be used to make smallerquantities of several products and canaccommodate slow reactions.
Which type would be used for:
A dyestuff
Sulphuric acidA pharmaceutical
Batch
BatchContinuous
