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

Correct Answer: Less number of trays are required

Bissoy MCQ
#Chemical Engineering #Mass Transfer

Related Questions

Flooding in a vapor-liquid contacting equipment occurs in a tray, when the pressure drop through a tray is __________ the liquid head available in the downcomer.
A Less than
B More than
C Same as
D Very much less
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
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
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
Bubble cap tray is the most commonly used tray in large distillation column, because
A Of its flexibility and nearly constant efficiency under varying conditions of operation
B It incurs less pressure drop as compared to any other try designed for the same duty
C It eliminates the foaming and entrain-ment tendency during operation
D None of these
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
With lapse of time, the overhead composition of light component in case of batch distillation with constant reflux
A Increases
B Decreases
C Remains same
D May increase or decrease ; depends on system
A dilute aqueous solution is to be concentrated in an evaporator system. High pressure steam is available. Multiple effect evaporator system is employed, because
A Total heat transfer area of all the effects is -less than that in a single effect evaporator system
B Total amount of vapor produced per Kg of feed steam in a multiple effect system is much higher than in a single effect
C Boiling point elevation in a single effect system is much higher than that in any effect in a multieffect system
D Heat transfer co-efficient in a single effect is much lower than that in any effect in a multieffect system
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
When a multistage tray tower uses a minimum reflux ratio, it implies
A Infinite trays and maximum reboiler heat load
B Infinite trays and minimum reboiler heat load
C Minimum trays and minimum reboiler heat load
D Minimum trays and maximum reboiler heat load

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