There are many types of distillation columns, each
designed to perform specific types of separations. |
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- One way of classifying distillation column type is to look
at how they are operated. Thus we have:
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- In batch operation, the feed to the column is introduced
batch-wise. That is, the column is charged with a 'batch' and then the distillation process is carried out. When the desired
task is achieved, a next batch of feed is introduced.
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- CONTINUOUS PROCESS COLUMNS
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- In contrast, continuous columns process a continuous feed
stream. No interruptions occur unless there is a problem with the column or surrounding process units. They are capable of
handling high throughputs and are the most common of the two types. We shall concentrate only on this class of columns.
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- Continuous columns can be further classified according to
the nature of the feed they are processing :
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- BINARY COMPONENT COLUMN
- Feed contains only two components
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- MULTI COMPONENT COLUMN
- Feed contains more than two components
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- MULTI PRODUCT COLUMN
- Column has more than two product streams
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- EXTRACTIVE DISTILLATION- where the extra feed appears
in the bottom product stream
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- AZEOTROPIC DISTILLATION- where the extra feed appears
at the top product stream
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- COLUMN INTERNAL STRUCTURE
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- TRAY COLUMN
- Trays of various designs are used to hold up the liquid
to provide better contact between vapour and liquid, hence better separation
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- PACKED COLUMN
- Packings are used to enhance contact between vapour
and liquid
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