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# Chemical Engineering- CH 2016 GATE Paper (Practice Test)

## 65 Questions MCQ Test GATE Past Year Papers for Practice (All Branches) | Chemical Engineering- CH 2016 GATE Paper (Practice Test)

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This mock test of Chemical Engineering- CH 2016 GATE Paper (Practice Test) for GATE helps you for every GATE entrance exam. This contains 65 Multiple Choice Questions for GATE Chemical Engineering- CH 2016 GATE Paper (Practice Test) (mcq) to study with solutions a complete question bank. The solved questions answers in this Chemical Engineering- CH 2016 GATE Paper (Practice Test) quiz give you a good mix of easy questions and tough questions. GATE students definitely take this Chemical Engineering- CH 2016 GATE Paper (Practice Test) exercise for a better result in the exam. You can find other Chemical Engineering- CH 2016 GATE Paper (Practice Test) extra questions, long questions & short questions for GATE on EduRev as well by searching above.
QUESTION: 1

### Q.No-1-5 Carry One Mark Each Q. The volume of a sphere of diameter 1 unit is than the volume of a cube of side 1 unit.

Solution:

Volume of a sphere of diameter 1 unit is 4/3π(1/2)3=π/6 and volume of a cube of side 1 unit is
13 = 1

QUESTION: 2

Solution:
QUESTION: 3

### Choose the statement(s) where the underlined word is used correctly: (i) A "prone" is a dried plum. (ii) He was lying "prone" on the floor. (iii) People who eat a lot of fat are "prone" to heart disease.

Solution:
QUESTION: 4

Fact: If it rains, then the field is wet.
(i) It rains
(ii) The field is not wet
(iii) The field is wet
(iv) It did not rain
Which one of the options given below is NOT logically possible, based on the given fact?

Solution:
QUESTION: 5

A window is made up of a square portion and an equilateral triangle portion above it. The base of
the triangular portion coincides with the upper side of the square. If the perimeter of the window
is 6 m, the area of the window in m2 is

Solution:

Area of the window = Area of square + Area of equilateral triangle = 1

[Perimeter of the window is 6 m
⇒ 4x+2x = 6, where x is length of each side]
⇒ x = 1

QUESTION: 6

Q.No-6-10 Carry Two Marks Each

Q.

Students taking an exam are divided into two groups, P and Q such that each group has the same
number of students. The performance of each of the students in a test was evaluated out of 200
marks. It was observed that the mean of group P was 105, while that of group Q was 85. The
standard deviation of group P was 25, while that of group Q was 5. Assuming that the marks were
distributed on a normal distribution, which of the following statements will have the highest
probability of being TRUE?

Solution:

QUESTION: 7

A smart city integrates all modes of transport, uses clean energy and promotes sustainable use of
resources. It also uses technology to ensure safety and security of the city, something which
critics argue, will lead to a surveillance state.
Which of the following can be logically inferred from the above paragraph?
(i) All smart cities encourage the formation of surveillance states.
(ii) Surveillance is an integral part of a smart city.
(iii) Sustainability and surveillance go hand in hand in a smart city.
(iv) There is a perception that smart cities promote surveillance.

Solution:
QUESTION: 8

Find the missing sequence in the letter series.
B, FH, LNP, _ _ _ _.

Solution:
QUESTION: 9

The binary operation ? is defined as a ? b = ab+(a+b), where a and b are any two real numbers.
he value of the identity element of this operation, defined as the number x such that a ? x = a, for
any a, is______.

Solution:

ax = aax + (a + x) = a
⇒x (1+ a) = 0a
⇒x = 0 is the identity element

QUESTION: 10

Which of the following curves represents the function

Here, x represents the abscissa and ? represents the ordinate.

Solution:

is a periodic function having period π and maximum value of y is 1 and y > 0.

QUESTION: 11

Q.No-11 - 35 Carry One Mark Each

Q.

Which one of the following is an iterative technique for solving a system of simultaneous linear
algebraic equations?

Solution:
QUESTION: 12

The Laplace transform of eat sin eat sin(bt)  is

Solution:

QUESTION: 13

What are the modulus (r) and argument (q) of the complex number 3 + 4i?

Solution:

QUESTION: 14

A liquid mixture of ethanol and water is flowing as inlet stream P into a stream splitter. It is split
into two streams, Q and R, as shown in the figure below.

The flow rate of P, containing 30 mass% of ethanol, is 100kg/h. What is the least number of
additional specification(s) required to determine the mass flow rates and compositions (mass %)
of the two exit streams?

Solution:

Independ ent material balance equations

Now, to solve equations (1) & (2) so as to determine all flow rates and mass compositions, both
mEtoH,Q m Q and mEtoH,R R have to be specified.
Least no. of additional specifications required = 2

*Answer can only contain numeric values
QUESTION: 15

The partial molar enthalpy (in kJ/mol) of species 1 in a binary mixture is given
by   , where x1 and x2 are the mole fractions of species 1 and 2,  respectively. The partial molar enthalpy (in kJ/mol, rounded off to the first decimal place) of species 1 at infinite dilution is ________

Imp : you should answer only the numeric value

Solution:

Partial molar enthalpy of species 1 at infinite dilution may be obtained from eqn. (1) by putting x1 = 0 and x2 = 1

QUESTION: 16

For a flow through a smooth pipe, the Fanning friction factor (f) is given by f =mRe−0.2 in the
turbulent flow regime, where Re is the Reynolds number and m is a constant. Water flowing
through a section of this pipe with a velocity 1m/s results in a frictional pressure drop of 10kPa. What
will be the pressure drop across this section (in kPa), when the velocity of water is 2 m/s?

Solution:

QUESTION: 17

In a cyclone separator used for separation of solid particles from a dust laden gas, the separation factor is defined as the ratio of the centrifugal force to the gravitational force acting on the particle. Sr denotes the separation factor at a location (near the wall) that is at a radial distance r  from the centre of the cyclone. Which one of the following statements is INCORRECT?

Solution:
*Answer can only contain numeric values
QUESTION: 18

A vertical cylindrical vessel has a layer of kerosene (of density 800 kg/m3) over a layer of water (of density 1000 kg/m3).L-shaped glass tubes are connected to the column 30 cm apart.  The  interface between the two layers lies between the two points at which the L - tube are connected. The levels (in cm) to which the liquids rise in the respective tubes are shown in the figure below.

The distance (x in cm, rounded off to the first decimal place) of the interface from the point at
which the lower L-tube is connected is _________________

Imp : you should answer only the numeric value

Solution:

*Answer can only contain numeric values
QUESTION: 19

A composite wall is made of four different materials of construction in the fashion shown below.
The resistance (in K/W) of each of the sections of the wall is indicated in the diagram

The overall resistance (in K/W, rounded off to the first decimal place) of the composite  wall in the direction of heat flow, is___

Imp : you should answer only the numeric value

Solution:

QUESTION: 20

Steam at 100oC is condensing on a vertical steel plate. The condensate flow is laminar. The average Nusselt numbers are Nu1 and Nu2, when the plate temperatures are 100  and 55o C.respectively. Assume the physical properties of the fluid and steel to remain constant within the temperature range of interest. Using Nusselt equations for film-type condensation, what is the value of the ratio Nu2/Nu1

Solution:

We have average heat transfer coefficient for Laminar flow through vertical plate condensation as

*Answer can only contain numeric values
QUESTION: 21

A binary liquid mixture of benzene and toluene contains 20 mol% of benzene. At 350 K the
vapour pressures of pure benzene and pure toluene are 92 kPa and 35 kPa, respectively. The
mixture follows Raoult’s law. The equilibrium vapour phase mole fraction (rounded off to
the second decimal place) of benzene in contact with this liquid mixture at 350 K is ________.

Imp : you should answer only the numeric value

Solution:

QUESTION: 22

Match the dimensionless numbers in Group-1 with the ratios in Group-2.

Solution:
QUESTION: 23

For what value of Lewis number, the wet-bulb temperature and adiabatic saturation temperature are nearly equal?

Solution:

When lewis number is unity, the wet-bulb temperature and adiabatic saturation temperature are equal

*Answer can only contain numeric values
QUESTION: 24

For a non-catalytic homogeneous reaction A→ B, the rate expression at 300 K is

where CA is the concentration of A (in mol/m3). Theoretically, the upper limit for the magnitude of the reactor rate (-rA in mol m-3s-1, rounded off to the first decimal place ) at 30K is _______________

Imp : you should answer only the numeric value

Solution:

QUESTION: 25

The variations of the concentrations (CA,CR and Cs) for three species (A, R and S) with time, in an isothermal homogeneous batch reactor are shown in the figure below.

Select the reaction scheme that correctly represents the above plot. The numbers in the reaction
schemes shown below, represent the first order rate constants in unit of s-1

Solution:

In the concentration-time plot, we find that  CR vs  t and C3 vs t  plots are identical. Thus, reaction rate constants of A→ R and A→S should be identical. Also, the concentration of A (CA) decreases monotonically.  Thus, the reactions should be irreversible

*Answer can only contain numeric values
QUESTION: 26

Hydrogen iodide decomposes through the reaction 2HI ⇔ H+ I2. The value of the universal gas constant R is 8.314 J mol-1K-1. The activation energy for the forward reaction is 184000 J mol-1 The ratio (rounded off to the first decimal place) of the forward reaction rate at 600 K to that at 550 K is ______________

Imp : you should answer only the numeric value

Solution:

QUESTION: 27

Match the instruments in Group-1 with process variables in Group-2.

Solution:
QUESTION: 28

What is the order of response exhibited by a U-tube manometer?

Solution:
QUESTION: 29

A system exhibits inverse response for a unit step change in the input. Which one of the
following statement must necessarily be satisfied?

Solution:
QUESTION: 30

Two design options for a distillation system are being compared based on the total annual cost.
Information available is as follows:

The annual fixed charge amounts to 12% of the installed cost. Based on the above information,
what is the total annual cost (Rs in lakhs /year) of the better option?

Solution:

Option P: Annual fixed charge = 12% of Rs 150 lakh
= 0.12 × 150
= Rs 18 lakh
Then, total annual cost (in lakhs/year)
= 18 + 6 +16 = 40
Option Q: Annual fixed charge = 12% of Rs 120 lakhs

= 0.12 × 120
=Rs 14.4 lakh
Then, total annual cost = 14.4 + 8 + 20 = 42.4 (in lakh/year)
Thus, option P is better, with lesser annual cost of Rs 40 lakh/year.

QUESTION: 31

Standard pipes of different schedule numbers and standard tubes of different BWG numbers are
available in the market. For a pipe / tube of a given nominal diameter, which one of the following
statements is TRUE?

Solution:
QUESTION: 32

Terms used in engineering economics have standard definitions and interpretations. Which one
of the following statements is INCORRECT?

Solution:

Payback period is calculated based on the payback time to cover up the fixed capital investment
only. So, statement (D) is false.

QUESTION: 33

India has no elemental sulphur deposits that can be economically exploited. In India, which one
of the following industries produces elemental sulphur as a by-product?

Solution:

In petroleum refineries, elemental sulphur is recovered from  H2 S and other gaseous streams in the Sulphur Recovery Unit (SRU).

QUESTION: 34

Two paper pulp plants P and Q use the same quality of bamboo as a raw material. The chemicals
used in their digester are as follows

Which one of the following statements is CORRECT?

Solution:

In Kraft process for manufacturing of paper, NaOH and Na2 S are used in the digester

Plant P uses Knaft process

QUESTION: 35

Match the industrial processes in Group-1, with the catalyst materials in Group-2.

Solution:

In ethylene polymerization, aluminium tri ethyl with TiCl3 promoter is used.
Cracking of petroleum feedstock requires zeolite as a catalyst material.
In the DCDA process for sulphuric acid manufacture, there is an oxidation step of SO2 to SO3,
where  V2 O5 (Vanadium pentoxide) is the catalyst

Hydrogenation of oil uses Nickel as catalyst

P-IV, Q-III, R-II, S-I

*Answer can only contain numeric values
QUESTION: 36

Q.No-36-65 Carry Two Marks Each

Q.

A set of simultaneous linear algebraic equations is represented in a matrix form as shown below.
The value (rounded off to the nearest integer) of x3 is

The value (rounded off to the nearest integer) of x3 is _________.

Imp : you should answer only the numeric value

Solution:

Augmented matrix of the given system is

By solving above equations (Backward substitutions)

x5 = 2, x4 = 5, x3 = 15, x2 = 10, x1 = 3

QUESTION: 37

What is the solution for the second order differential equation  with the initial
conditions

Solution:

*Answer can only contain numeric values
QUESTION: 38

The model y = mx2 is to be fit to the data given below.

Using linear regression, the value (rounded off to the second decimal place) of m is

Imp : you should answer only the numeric value

Solution:

Given that y = mx2
By taking log on both sides

log y = logm = 2log x
put log y = Y; logm = a; log x= X

⇒ Y = a+ 2X

*Answer can only contain numeric values
QUESTION: 39

The Lagrange mean-value theorem is satisfied for   f (x) = x3 + 5, in the interval (1, 4) at a value
(rounded off to the second decimal place) of x equal to __________.

Imp : you should answer only the numeric value

Solution:

By Lagrange’s mean value theorem there exists C is (1, 4) such that

Lagrange’s means value theorem satisfied

*Answer can only contain numeric values
QUESTION: 40

Values of f (x) in the interval [0, 4] are given below.

Using Simpson’s 1/3 rule with a step size of 1, the numerical approximation (rounded off to the
second decimal place) of

Imp : you should answer only the numeric value

Solution:

QUESTION: 41

A jacketed stirred tank with a provision for heat removal is used to mix sulphuric acid and water
in a steady state flow process. H2SO4 ( ) enters at a rate of 4 kg/h at 25oC and H2O ( ) enters at
a rate of 6 kg/h at 10oC. The following data are available:
Specific heat capacity of water = 4.2 kJ kg?1K?1.
Specific heat capacity of aqueous solution of 40 mass% H2SO4 = 2.8 kJ (kg solution)?1 K?1.
Assume the specific heat capacities to be independent of temperature.
Based on reference states of H2SO4 ( ) and H2O ( ) at 25oC, the heat of mixing for aqueous
solution of 40 mass% H2SO4 = ? 650 kJ (kg H2SO4)?1.
If the mixed stream leaves at 40oC, what is the rate of heat removal (in kJ/h)?

Solution:
*Answer can only contain numeric values
QUESTION: 42

An ideal gas is adiabatically and irreversibly compressed from 3 bar and 300 K to 6 bar in a closed system. The work required for the irreversible compression is 1.5 times the work that is required for reversible compression from the same initial temperature and pressure to the same final pressure. The molar heat capacity of the gas at constant volume is 30 J mol-1 K-1 (assumed to be independent of temperature); universal gas constant, R is 8.314 J mol-1 K-1; ratio of molar heat capacities is 1.277. The temperature (in K, rounded off to the first decimal place) of the gas at the final state in the irreversible compression case is __________.

Imp : you should answer only the numeric value

Solution:

*Answer can only contain numeric values
QUESTION: 43

A gas obeying the Clausius equation of state is isothermally compressed from 5 MPa to 15 MPa
in a closed system at 400 K. The Clausius equation of state is where P is the
pressure, T is the temperature, n is the molar volume and R is the universal gas constant.The
parameter b in the above equation varies with temperature as b(T) = b0 + b1T with
b0=4 x 10-5m3mol-1 and b1= 1.35 x 10-7 m3mol-1K-1 . The effect of pressure on the molar enthalpy (h) at a constant temperature is given by .Let hi and hf denote initial and
final molar enthalpies, respectively. The change in the molar enthalpy hf -hi (in J mol-1, rounded
off to the first decimal place) for this process is________

Solution:

*Answer can only contain numeric values
QUESTION: 44

A binary system at a constant pressure with species ‘1’ and ‘2’ is described by the two-suffix
Margules equation, gE/RT =3x1x2. where E g is the molar excess Gibbs free energy, R is the
universal gas constant, T is the temperature and 1 2 x , x are the mole fractions of species 1 and 2,
respectively. At a temperature T, g1/RT =1  and g2/RT =2 where g1 and g2 are the molar Gibbs free
energies of pure species 1 and 2, respectively. At the same temperature, g represents the molar
Gibbs free energy of the mixture. For a binary mixture with 40 mole % of species 1, the value
(rounded off to the second decimal place) of g/RT is ___________

Solution:

(According to definition of excess properties)

Now,  x1 = 0.4, x2 = 0.6

QUESTION: 45

Water (density=1000 kg m?3) is pumped at a rate of 36 m3/h, from a tank 2 m below the pump, to
an overhead pressurized vessel 10 m above the pump. The pressure values at the point of suction
from the bottom tank and at the discharge point to the overhead vessel are 120 kPa and
240 kPa, respectively. All pipes in the system have the same diameter. Take acceleration due to
gravity, g = 10 ms?2. Neglecting frictional losses, what is the power (in kW) required to deliver
the fluid?

Solution:

QUESTION: 46

An agitated cylindrical vessel is fitted with baffles and flat blade impellers. The power number for
this system is given by where P is the power consumed for the mixing, ρ is the
density of the fluid, n is the speed of the impeller and D is the diameter of the impeller. The
diameter of the impeller is 1/3rd the diameter of the tank and the height of liquid level is equal to
the tank diameter. The impeller speed to achieve the desired degree of mixing is 4 rpm. In a
scaled up design, the linear dimensions of the equipment are to be doubled, holding the power
input per unit volume constant. Assuming the liquid to be Newtonian and to be independent of
Reynolds number, what is the impeller speed (in rpm) to achieve the same degree of mixing in the
scaled up vessel?

Solution:

*Answer can only contain numeric values
QUESTION: 47

Consider a rigid solid sphere falling with a constant velocity in a fluid. The following data are
known at the conditions of interest: viscosity of the fluid = 0.1 Pa s, acceleration due to gravity =
10 m s-2, density of the particle = 1180 kg m-3 and density of the fluid = 1000 kg m-3. The
diameter (in mm, rounded off to the second decimal place) of the largest sphere that settles in the
Stokes’ law regime (Reynolds number 0.1), is_________

Imp : you should answer only the numeric value

Solution:

QUESTION: 48

The characteristics curve (Head – Capacity relationship) of a centrifugal pump is represented by
the equation is the head developed by the pump (in m) and Q is
the flow rate (in m3/h) through the pump. This pump is to be used for pumping water through a
horizontal pipeline. The frictional head loss ΔHpiping (in m) is related to the water flow rate QL (in
m3/h) by the equation . The flow rate (in m3/h, rounded off to the
first decimal place) of water pumped through the above pipeline, is ____________.

Solution:

*Answer can only contain numeric values
QUESTION: 49

Water flows through a smooth circular pipe under turbulent conditions. In the viscous sub-layer, the
velocity varies linearly with the distance from the wall. The Fanning friction factor is defined as,where tw is the shear stress at the wall of the pipe, ρ is the density of the fluid and is the average velocity of 1ms-1  through the pipe. For this flow condition, the friction factor f is 0.005. At a distance of 0.05 mm from the wall of the pipe (in the viscous sub-layer), the velocity (in  ms-1 ,rounded off to the third decimal place), is __________.

Solution:

QUESTION: 50

In a 1-1 pass shell and tube exchanger, steam in condensing in the shell side at a temperature (Ts)
of 135oC and the cold fluid is heated from a temperature (T1) of 20oC to a temperature (T2) of
90oC.

The energy balance equation for this heat exchanger is

Where U is the overall heat transfer coefficient, A is the heat transfer area,   is the mass flow rate of the cold fluid and Cp is the its specific heat. Tube side fluid is in a turbulent flow and
the heat transfer coefficient can be estimated from the following equation:

Nu= 0.023(Re)0.8 (Pr) 1/3

where Nu is the Nusselt number, Re is the Reynolds number and Pr is the Prandtl number. The
condensing heat transfer coefficient in the shell side is significantly higher than the tube side heat transfer coefficient. The resistance of the wall to heat transfer is negligible. If only the mass flow rate of the cold fluid is doubled, what is the outlet temperature (in oC) of the cold fluid at steady state?

Solution:
QUESTION: 51

In an experimental setup, mineral oil is filled in between the narrow gap of two horizontal smooth plates. The setup has arrangements to maintain the plates at desired uniform temperatures. At these temperatures, ONLY the radiative heat flux is negligible.The thermal conductivity of the oil does not vary perceptibly in this temperature range. Consider four experiments at steady state under different experimental conditions, as shown in the figure below. The figure shows plate temperatures and the heat fluxes in the vertical direction.

What is the steady state heat flux ( in  W m-2 ) with the top plate at 70o C and the bottom plate at 40oC?

Correct answer will be updated soon

Solution:
*Answer can only contain numeric values
QUESTION: 52

The space between two hollow concentric spheres of radii 0.1 m and 0.2 m is under vacuum.
Exchange of radiation (uniform in all directions) occurs only between the outer surface (S1)  of the smaller sphere and the inner surface (S2) of the larger sphere. The fraction (rounded off to the second decimal place) of the radiation energy leaving S2 . Whcih reaches S1 is ____________.

Solution:

We know that A1 F12 = A2 F21

*Answer can only contain numeric values
QUESTION: 53

A binary distillation column is to be designed using McCabe Thiele method. The distillate
contains 90 mol% of the more volatile component. The point of intersection of the q-line with the
equilibrium curve is (0.5, 0.7). The minimum reflux ratio (rounded off to the first decimal place)
for this operation is __________.

Solution:

It is evident from above figure that the operating line for the enriching section, corresponding to the minimum reflux ratio, passes through the point of intersection the equilibrium curve and qline.

QUESTION: 54

Solute C is extracted in a batch process from its homogenous solution of A and C, using solvent
B. The combined composition of the feed and the extracting solvent is shown in the figure below
as point M, along with the tie line passing through it. The ends of the tie line are on the
equilibrium curve.

What is the selectivity for C?

Solution:

Selectivity in liquid-liquid extraction is analogous to relative volatility in distillation. By definition, selectivity for C

QUESTION: 55

At 30oC the amounts of acetone adsorbed at  partial pressure  of 10 and 100 mmHg are 0.1 and 0.4 kg acetone/kg activated carbon, respectively. Assume Langmuir isotherm describes the adsorption of acetone on activated carbon. What is the amount of acetone adsorbed (in kg per kg
of activated carbon) at a partial pressure of 50 mmHg and 30oC?

Solution:

QUESTION: 56

Consider the following two cases for a binary mixture of ideal gases A and B under steady state
conditions. In Case 1, the diffusion of A occurs through non-diffusing B. In Case 2, equimolal
counter diffusion of A and B occurs. In both the cases, the total pressure is 100 kPa and the partial
pressures of A at two points separated by a distance of 10 mm are 10 kPa and 5 kPa. Assume that
the Fick’s first law of diffusion is applicable. What is the ratio of molar flux of A in Case 1 to that
in Case 2?

Solution:

*Answer can only contain numeric values
QUESTION: 57

The liquid phase reversible reaction A⇔B is carried out in an isothermal CSTR operating under
steady state conditions. The inlet stream does not contain B and the concentration of A in the
inlet stream is 10 mol/lit. The concentrations of A at the reactor exit, for residence times of 1 s
and 5s are 8 mol/lit and 5 mol/lit, respectively. Assume the forward and backward reactions
are elementary following the first order rate law. Also assume that the system has constant
molar density. The rate constant of the forward reaction (in s?1, rounded off to the third decimal
place) is __________.

Solution:

*Answer can only contain numeric values
QUESTION: 58

A liquid phase irreversible reaction A→ B is carried out in an adiabatic CSTR operating under steady state conditions. The reaction is elementary and follows the first order rate law. For this reaction, the figure below shows the conversion (XA) of A as a function of temperature (T) for different values of the rate of reaction (-γin mol  m-3s-1)denoted by the numbers to the left of each curve. This figure can be used to determine the rate of the reaction at a particular temperature, for a given conversion of A.

The inlet stream does not contain B and the concentration of A in the inlet stream is 5 mol/m
The molar feed rate of A is 100 mol/s. A steady state energy balance for this CSTR results in
the following relation: T 350 25Xwhere T is the temperature (in K) of the exit stream and  XA is the conversion of A in the CSTR. For an exit conversion of 80 % of A, the volume (in m3, rounded off to the first decimal place) of CSTR required is______

Solution:

QUESTION: 59

A porous pellet with Pt dispersed in it is used to carry out a catalytic reaction. Following two
scenarios are possible.
Scenario 1: Pt present throughout the pores of the pellet is used for catalyzing the reaction.

Scenario 2: Pt present only in the immediate vicinity of the external surface of the pellet is used for catalyzing the reaction.

At a large value of Thiele modulus, which one of the following statements is TRUE?

Solution:

So, high thick modulus means reaction rate is much greater then diffusion rate.
Now, since diffusion rate is slow, it would be difficult for reactants to diffuse into the pores of the pellet. It would be beneficial if pt is present only in the immediate vicinity of the external surface of pellet

QUESTION: 60

A CSTR has a long inlet pipe. A tracer is injected at the entrance of the pipe. The E-curve obtained at the exit of the CSTR is shown in the figure below

Assuming plug flow in the inlet pipe, the ratio (rounded off to the second decimal place) of the
volume of the pipe to that of the CSTR is_________

Correct Answer will be update Soon

Solution:
*Answer can only contain numeric values
QUESTION: 61

A liquid flows through an “equal percentage” valve at a rate of 2m3/h when the valve is 10%
open. When the valve opens to 20% the flow rate increases to 3m3/h. Assume that the pressure
drop across the valve and the density of the liquid remain constant. When the valve opens to 50%,
the flow rate (in m3/h, rounded off to the second decimal place) is __________.

Imp : you should answer only the numeric value

Solution:

For equal percentage valve  f=foebx
Given, f = 2 at x = 0.1
f = 3 at x = 0.2
x = % of opening
f = flow rate
Now at x = 0.5 , what is f= 10.3 m3 h

*Answer can only contain numeric values
QUESTION: 62

A PI controller with integral time constant of 0.1 min is to be designed to control a process with
transfer function.

Assume the transfer functions of the measuring element and the final control element are both
unity (  Gm =1, Gf =1) . The gain (rounded off to the first decimal place) of the controller that
will constitute the critical condition for stability of the PI feedback control system is________

Imp : you should answer only the numeric value

Solution:

QUESTION: 63

For a unit step input, the response of a second order system is

where, Kp is the steady state gain, ζ is the damping coefficient,  is the natural period of oscillation and φ is the phase lag. The overshoot of the system is exp  For a unit
step input, the response of the system from an initial steady state condition at t = 0 is shown in the figure below.

What is the natural period of oscillation (in seconds) of the system?

Solution:

We can find ε from above equation
T – valve can be determined as the period between two peaks as 100

QUESTION: 64

A vertical cylindrical tank with a flat roof and bottom is to be constructed for storing 150mof ethylene glycol. The cost of material and fabrication for the tank wall is Rs 6000 per m2 and the same for the roof and the tank bottom are Rs 2000 and Rs 4000 per m2    respectively. The cost of accessories, piping and instruments can be taken as 10% of the cost of the wall.  10%  of the volume of the tank needs to be kept free as vapour space above the liquid storage. What is the optimum diameter (in m) for the tank?

Solution:

10% of tank volume to be kept free as vapour space
90% of tank volume to be used for liquid storage

h →height of tank

QUESTION: 65

A catalytic reforming plant produces hydrogen and benzene from cyclohexane by dehydro aromatisation. In order to increase the production of hydrogen, the owner plans to change the process to steam reforming of the same feedstock that produces hydrogen and carbon dioxide. Stoichiometrically, what is the maximum ratio of pure hydrogen produced in the proposed process to that in the existing process?

Solution:

De-hydro aromatisatin of cyclohexane to produce hydrogen and benzene

C6 H12 →C6 H6 + 3H2

Steam reforming of cyclo hexane to from CO2 and H2

C6 H12 → 6CO+ 18H2

So, according to stoichiometry, ratio of hydrogen in proposed process to that in existing process

18/3 =6