Chemical Engineering Gate Yearwise 


Chemical Engineering Gate 2023 Questions with Answer

Ques 14 GATE 2023

A cascade control strategy is shown in the figure below. The transfer function between the output (y) and the secondary disturbance (d2) is defined as
Gydβ‚‚(s) = y(s)/d2(s).
Which one of the following is the CORRECT expression for the transfer function Gydβ‚‚(s)?

A

1/((11s+21)(0.1s+1))

B

1/((s+1)(0.1s+1))

C

(s+1)/((s+2)(0.1s+1))

D

(s+1)/((s+1)(0.1s+1))


(a) is the correct answer.

Ques 15 GATE 2023

Level (β„Ž) in a steam boiler is controlled by manipulating the flow rate (𝐹) of the make-up (fresh) water using a proportional (P) controller. The transfer function between the output and the manipulated input is
β„Ž(𝑠)/𝐹(𝑠)=0.25(1βˆ’π‘ )/ 𝑠(2𝑠+1).
The measurement and valve transfer functions are both equal to 1. A process engineer wants to tune the controller so that the closed-loop response gives decaying oscillations under servo mode. Which one of the following is the CORRECT value of the controller gain to be used by the engineer?

A

0.25

B

2

C

4

D

6


(d) is the correct answer.

Ques 16 GATE 2023

Which of the following statements is/are CORRECT?

A

Bond number includes surface tension.

B

Jakob number includes latent heat.

C

Prandtl number includes liquid-vapor density difference.

D

Biot number includes gravity.


(a, b) is the correct answer.

Ques 17 GATE 2023

Wet air containing 10 mole percent water vapor is dried by continuously passing it through a column of CaCl2 pellets. The pellets remove 50 percent of water from wet air entering the column. The mole percent of water vapor in the product stream exiting the column is ___________ (rounded off to two decimal places).


(5.00) is the correct answer.

Ques 18 GATE 2023

Orsat analysis showing the composition (in mol %, on a dry basis) of a stack gas is given in the table below. The humidity measurement reveals that the mole fraction of H2O in the stack gas is 0.07. The mole fraction of N2 calculated on a wet basis is ________ (rounded off to two decimal places).


(0.09) is the correct answer.

Ques 19 GATE 2023

Fresh catalyst is loaded into a reactor before the start of the following catalytic reaction. The catalyst gets deactivated over time. The instantaneous activity a(t), at time t, is defined as the ratio of the rate of reaction βˆ’rβ€²A(t) (molΒ·(g cat)βˆ’1Β·hrβˆ’1) to the rate of reaction with fresh catalyst. Controlled experimental measurements led to an empirical correlation:
βˆ’rβ€²A(t) = βˆ’0.5 t + 10
where t is in hours. The activity of the catalyst at t = 10 hr is _______ (rounded off to one decimal place).


(0.5) is the correct answer.

Ques 20 GATE 2023

An irreversible liquid-phase second-order reaction

with rate constant k = 0.2 liter.mol−1min−1, is carried out in an isothermal non-ideal reactor. A tracer experiment conducted on this reactor resulted in a residence time distribution (E-curve) as shown in the figure below. The areas of the rectangles (i), (ii), and (iii) are equal. Pure A at a concentration of 1.5 mol.liter−1 is fed to the reactor. The segregated model mimics the nonideality of this reactor. The percentage conversion of A at the exit of the reactor is ______ (rounded off to the nearest integer).


(4) is the correct answer.

Ques 21 GATE 2023

The outlet concentration CA of a plug flow reactor (PFR) is controlled by manipulating the inlet concentration CA0. The following transfer function describes the dynamics of this PFR.
CA(s) / CA0(s) = exp[−(V / F)(k + s)]
In the above equation, V = 1 m3, F = 0.1 m3min−1, and k = 0.5 min−1. The measurement and valve transfer functions are both equal to 1. The ultimate gain, defined as the proportional controller gain that produces sustained oscillations, for this system is ______ (rounded off to one decimal place).


(63) is the correct answer.

Ques 22 GATE 2023

The transfer function of a measuring instrument is

At time 𝑑=0, a step change of +1 unit is introduced in the input of this instrument. The time taken by the instrument to show an increase of 1 unit in its output is _____ (rounded off to two decimal places).


(1.7) is the correct answer.

Ques 23 GATE 2023

A design engineer needs to purchase a membrane module (M) for a plant. Details about the two available options, M1 and M2, are given in the table below. The overall plant has an expected life of 7 years. If the interest rate is 8 % per annum, compounded annually, the difference in the net present value (NPV) of these two options, in lakhs of rupees, is ______ (rounded off to one decimal place).


(1.95) is the correct answer.

Ques 24 GATE 2023

The purchase cost of a new distillation column is Rs.10 lakhs with an installation factor of 5.8. The cost of the capital is to be annualized over a period of 6 years at a fixed rate of interest of 5 % per annum, compounded annually. The annual cost (in lakhs of rupees) of the installed capital is _______ (rounded off to one decimal place).


(1.8) is the correct answer.

Ques 25 GATE 2023

Pumps 𝐴 and 𝐡 are being considered for purchase in a chemical plant. Cost details for these two pumps are given in the table below. The interest rate is 10 % per annum, compounded annually. For both the pumps to have the same capitalized cost, the salvage value (in Rs.) of pump B should be ______ (rounded off to the nearest integer).


(29091) is the correct answer.

Ques 26 GATE 2023

The coefficient of π‘₯4 in the polynomial (π‘₯βˆ’1)3(π‘₯βˆ’2)3 is equal to _______.

A

33

B

-3

C

30

D

21


(b) is the correct answer.

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