Chemical Reaction Engineering GATE-2017

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Q 1: The following reaction rate curve is shown for a reaction A\rightarrow P . Here, (−rA) and XA represent reaction rate and conversion, respectively. The feed is pure A and 90 % conversion is desired.

Which of the following reactor configurations gives the lowest total volume of the reactor (s)?





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Q 2: Consider a first-order catalytic reaction in a porous catalyst pellet. Given R – characteristic length of the pellet: De – effective diffusivity; kC – mass transfer coefficient: k1 – rate constant based on the volume of the catalyst pellet; Cs – concentration of reactant on the pellet surface. The expression for Thiele modulus is





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Q 3: For a solid-catalyzed gas phase reversible reaction, which of the following statements is ALWAYS TRUE?





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Q 4: Reaction A\rightarrow B  is carried out in a reactor operating at a steady state and 1 mol/s of pure A at 425 ˚C enters the reactor. The outlet stream leaves the reactor at 325 ˚C. The heat input to the reactor is 17 kW. The heat of the reaction at the reference temperature of 25 ˚C is 30 kJ/mol. The specific heat capacities (in kJ/mol.K) of A and B are 0.1 and 0.15, respectively. The molar flow rate of B leaving the reactor, rounded to 2 decimal places, is  _______ mol/s.

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Q 5: The C-curve measured during a pulse tracer experiment is shown below. In the figure, C(t) is the concentration of the tracer measured at the reactor exit in mol/liter at time t seconds.

The mean residence time in the reactor, rounded to 1 decimal place, is ___________.

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Q 6: The following liquid second-order reaction is carried out in an isothermal CSTR at steady state

A\rightarrow R;\;-r_A=0.005C_A^2\frac{mol}{m^3.hr}

Where CA is the concentration of the reactant in the CSTR. The reactor volume is 2 m3, the inlet flow rate is 0.5 m3/hr and the inlet concentration of the reactant is 1000 mol/m3. The fractional conversion, rounded to 2 decimal places, is _________.

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Q 7: The reversible reaction of t-butyl alcohol (TBA) and ethanol (EtOH) to ethyl t-butyl ether (ETBE) is

TBA+EtOH\leftrightarrow ETBE+Water

The equilibrium constant for this reaction is KC = 1. Initially, 74 g of TBA is mixed with 100 g of aqueous solution containing 46 wt% ethanol. The molecular weights are 74 g/mol for TBA, 46 g/mol for EtOH, 102 g/mol for ETBE, and 18 g/mol for water. The mass of ETBE at equilibrium, rounded to 1 decimal place, is ________________ g.

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Q 8: The following gas-phase reaction is carried out in a constant-volume isothermal batch reactor

A+B\rightarrow R+S

The reactants A and B as well as the product S are non-condensable gases. At the operating temperature, the saturation pressure of the product R is 40 kPa. Initially, the batch reactor contains equimolar amounts of A and B (and no products) at a total pressure of 100 kPa. The initial concentrations of the reactants are CA,0 = CB,o = 12.5 mol/m3. The rate of reaction is given by -r_A=0.08C_AC_B\;mol/m^3.s . The time at which R just starts condensing, rounded to 1 decimal place, is __________.

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