Related Questions

In a continuous distillation column, the optimum reflux ratio ranges from __________ times the minimum reflux ratio.
A 1.1 to 1.5
B 1.6 to 2
C 2.2 to 2.6
D 2.7 to 3
Total reflux in a distillation operation requires minimum
A Reboiler load
B Number of plates
C Condenser load
D All of the above
A distillation column with N plates is being operated under normal conditions. At some point of time, the operation is shifted to total reflux condition (i.e., no product and residue are being withdrawn and feed to the column is stopped). At the new steady state,
A Composition of vapors and that of liquid do not vary throughout the column
B Reboiler load and condenser load are minimum
C The top and bottom compositions are unchanged with and without total reflux
D The top and bottom compositions correspond to the maximum enrichment available
Minimum reflux ratio in a distillation column results in
A Optimum no. of trays
B Minimum reboiler size
C Maximum condenser size
D Minimum number of trays
The feed to fractionating column is changed from saturated vapour to saturated liquid. If the separation and reflux ratio remains unchanged, the number of ideal stages will
A Increase
B Decrease
C Remains same
D Depend on saturated boiling point; may increase or decrease
As the reflux ratio decreases, the
A Separation becomes more efficient
B Number of plates increases
C Column diameter increases
D None of these
In case of binary distillation, increasing the reflux ratio above optimum does not result in the increase of
A Area between operating line and 45° diagonal x-y diagram
B Condenser and reboiler surfaces
C Tower cross-section
D None of these
An aqueous solution of methanol is to be distilled in a tray column. High pressure steam is available as a source of heat. For a given reflux ratio and overhead composition, two options are being explored; (i) a reboiler is used and (ii) no reboiler is used but steam is fed directly to the bottom of the column. As compared to option (i), in option (ii)
A Less number of trays are required
B Composition of the residue remains unchanged
C More number of trays are required but the residue composition remains unchanged
D More number of trays are required and the residue composition is more dilute in methanol
The slope of operating line in the rectifying section of a distillation column is unity, if the reflux ratio is
A 0
B ∞
C 1
D Minimum
For the same process conditions, the reflux ratio of an unlagged distillation column
A Decreases in winter
B Increases in winter
C Increases in summer
D None of these

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