Related Questions

In batch distillation with constant reflux, overhead product composition __________ with time.
A Increases
B Decreases
C Does not vary
D May increase on decrease, depends on the system
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
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
For a fixed number of ideal stages in a distillation column, as the reflux ratio is increased, the difference in composition between the top and bottom product streams
A Increases
B Decreases
C Remains unaffected
D Passes through a maximum
What is the reflux ratio at total reflux?
A Zero
B Infinity
C Unity
D Data insufficient
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
In case of a continuous distillation column, increase in reflux ratio may result in the
A Lower fixed charges for the column
B Greater cost for the reboiler heat supply
C Greater cost for the condenser coolant
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 At some point of time, the operation is shifted to total reflux condition (i.e., no product and residue are being withdrawn and feed to the column is stopped).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
The time interval from when the given star passes directly overhead to when it next passed directly overhead, is defined as
A one sidereal day
B one solar day
C both the terms are similar, so any of these may be used
D None of the above
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

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