GATE CH branch:ch PYQs & Answers — Page 39

Questions 381–390 of 650. Imported answers require independent review unless marked reviewed.

Topic practice 650 questionsPage 39 of 65

A distillation column handling a binary mixture of A and B is operating at total reflux. It has two ideal stages including the reboiler. The mole fraction of the more volatile component in the residue (

) is 0.1.

The average relative volatility

is 4. The mole fraction of A in the distillate (

) is ________ (round off to 2 decimal places).

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In a batch drying experiment, a solid with a critical moisture content of 0.2 kg H

O/kg dry solid is dried from an initial moisture content of 0.35 kg H

O/kg dry solid to a final moisture content of 0.1 kg H

O/kg dry solid in 5 h. In the constant rate regime, the rate of drying is 2 kg H

O/(m

·h).

The entire falling rate regime is assumed to be uniformly linear. The equilibrium moisture content is assumed to be zero.

The mass of the dry solid per unit area is ________ kg/m

(round off to nearest integer).

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As shown in the figure below, air flows in parallel to a freshly painted solid surface of width 10 m, along the z-direction.

Diagram for Chemical Engineering question 48

The equilibrium vapor concentration of the volatile component A in the paint, at the air-paint interface, is

. The concentration

decreases linearly from this value to zero along the y-direction over a distance

of 0.1 m in the air phase. Over this distance, the average velocity of the air stream is 0.033 m s

and its velocity profile (in m s

) is given by

where y is in meter.

Let

represent the flow averaged concentration. The ratio of

is ________ (round off to 2 decimal places).

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The following isothermal autocatalytic reaction,

is carried out in an ideal continuous stirred tank reactor (CSTR) operating at steady state. Pure A at 1 mol L

is fed, and 90% of A is converted in the CSTR. The space time of the CSTR is ________ seconds.

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Reactant A decomposes to products B and C in the presence of an enzyme in a well-stirred batch reactor. The kinetic rate expression is given by

If the initial concentration of A is 0.02 mol L

, the time taken to achieve 50% conversion of A is ________ min (round off to 2 decimal places).

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The following homogeneous, irreversible reaction involving ideal gases,

is carried out in a steady state ideal plug flow reactor (PFR) operating at isothermal and isobaric conditions. The feed stream consists of pure A, entering at 2 m s

In order to achieve 50% conversion of A, the required length of the PFR is ________ meter (round off to 2 decimal places).

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A system has a transfer function

. When a step change of magnitude M is given to the system input, the final value of the system output is measured to be 120. The value of M is ________.

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A process has a transfer function

. Initially the process is at steady state with

and

. If a step change in x is given from 0.4 to 0.5, the maximum value of y that will be observed before it reaches the new steady state is ________ (round off to 1 decimal place).

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Operating labor requirements L in the chemical process industry is described in terms of the plant capacity C (kg day

) over a wide range (

–

) by a power law relationship

where

and

are constants. It is known that

is 60 when

is 70 when

The value of L when C is

kg day

is ________ (round off to nearest integer).

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A viscous liquid is pumped through a pipe network in a chemical plant. The annual pumping cost per unit length of pipe is given by

The annual cost of the installed piping system per unit length of pipe is given by

Here, D is the inner diameter of the pipe in meter, q is the volumetric flowrate of the liquid in m

and

is the viscosity of the liquid in Pa.s. If the viscosity of the liquid is

Pa.s and the volumetric flow rate of the liquid is

, the economic inner diameter of the pipe is ________ meter (round off to 3 decimal places).

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GATE CH branch:ch PYQs

Question 46

Question 47

Question 48

Question 49

Question 50

Question 51

Question 52

Question 53

Question 54

Question 55