GATE CH kind:question PYQs & Answers — Page 13

Questions 121–130 of 650. Imported answers require independent review unless marked reviewed.

Topic practice 650 questionsPage 13 of 65

Solute

is absorbed from a gas into water in a packed bed operating at steady state. The absorber operating pressure and temperature are 1 atm and 300 K, respectively. At the gas-liquid interface

where

and

are the interfacial gas and liquid mole fractions of

, respectively. At a particular location in the absorber, the mole fractions of

in the bulk gas and in the bulk water are 0.02 and 0.002, respectively. If the ratio of the local individual mass transfer coefficients for the transport of

on the gas-side (

) to that on the water-side (

, then

equals ____ (rounded off to 3 decimal places).

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Components

and

form an azeotrope. The saturation vapour pressures of

and

at the boiling point are 87 kPa and 72.7 kPa, respectively. The azeotrope composition is ____ mol%

(rounded off to the nearest integer).

GIVEN:

where

and

are the liquid phase mole fraction and activity coefficient of component

, respectively.

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The reaction

with reaction rate,

, occurs in an isothermal PFR operating at steady state. The conversion (

) at two axial locations (1 and 2) of the PFR is shown in the figure.

Diagram for Chemical Engineering question 58

The value of

is ____ (rounded off to 2 decimal places).

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The catalytic gas phase reaction

is carried out in an isothermal batch reactor of 10 L volume using 0.1 kg of a solid catalyst. The reaction is first-order with

where

and

is the concentration of

in mol/L.

The catalyst activity

undergoes first order decay with rate constant

per hour and

The reactant conversion after 1 day of operation is ____ (rounded off to 2 decimal places).

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Consider a process with transfer function

A first-order plus dead time (FOPDT) model is to be fitted to the unit step process reaction curve (PRC) by applying the maximum slope method.

Let

and

denote the time constant and dead time, respectively, of the fitted FOPDT model. The value of

is ____ (rounded off to 2 decimal places).

GIVEN: For

the unit step output response:

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Methanol is produced by the reversible, gas-phase hydrogenation of carbon monoxide as

and

are charged to a reactor and the reaction proceeds to equilibrium at 453 K and 2 atm. The reaction equilibrium constant, which depends only on the temperature, is 1.68 at the reaction conditions. The mole fraction of

in the product is 0.4. Assuming ideal gas behaviour, the mole fraction of methanol in the product is ____ (rounded off to 2 decimal places).

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The block diagram of a series cascade control system (with time in minutes) is shown in the figure. For

min and

, the maximum value of

, below which the cascade control system is stable, is ____ (rounded off to the nearest integer).

Diagram for Chemical Engineering question 62

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It is proposed to install thermal insulation in a residence to save on the summer-monsoon season air-conditioning costs. The estimated yearly saving is 20 thousand rupees. The cost of installation of the insulation is 150 thousand rupees. The life of the insulation is 12 years. For a compound interest rate of 9% per annum, the minimum salvage value of the insulation for which the proposal is competitive, is ____ thousand rupees (rounded off to nearest integer).

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Consider the flowsheet in the figure for manufacturing

via the reaction

in an isothermal CSTR. The split in the separator is perfect so that the recycle stream is free of

and the product stream is pure

. Let

denote the mole fraction of species

(

) in the CSTR, which is operated in excess

with

. The reaction is first-order in

with the reaction rate

, where

kmol/(m

h).

Diagram for Chemical Engineering question 64

The reactor volume

in m

is to be optimized to minimize the cost objective

, where

is the recycle rate in kmol/h. For a product rate

kmol/h, the optimum value of

is ____ m

(rounded off to the nearest integer).

GIVEN:

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A wet solid of 100 kg containing 30 wt% moisture is to be dried to 2 wt% moisture in a tray dryer. The critical moisture content is 10 wt% and the equilibrium moisture content is 1 wt%. The drying rate during the constant rate period is 10 kg/(h m

). The drying curve in the falling rate period is linear. If the drying area is 5 m

, the time required for drying is ____ h (rounded off to 1 decimal place).

Note: All the moisture values given are on dry-solid basis.

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GATE CH kind:question PYQs

Question 56

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Question 58

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Question 60

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Question 62

Question 63

Question 64

Question 65