Chemical reaction engineering quiz 2018

CHEMICAL REACTION ENGINEERING QUIZ

Q. 1 The elementary second-order liquid phase reaction A + B → C + D is carried out in an isothermal plug flow reactor of 2 m³ volume. The inlet volumetric flow rate is 10 m³ /h . The initial concentrations of both A and B are 2 kmol/m³. The rate constant is given as 2.5 m³ kmol^-1 h^-1. The percentage conversion of A is.

Q. 2. Liquid phase isomerization of o-xylene to p-xylene using a zeolite catalyst was carried out in a CSTR. Three sets of kinetic data at different temperatures and stirring speeds were obtained as shown below.

The operating condition at which the reaction rate is not controlled by external mass transfer resistance is

T = 500 K; rpm = 3000
T = 600 K; rpm = 1000
T = 700 K; rpm = 1000
T = 700 K; rpm = 2000

Q. 3 For a chemical reaction, the ratio of rate constant at 500 K to that at 400 K is 2.5. Given R= 8.314J mol^-1 K^-1, the value of activation energy (in kJ/mol) is

10.5
12.0
15.2
18.4

Q. 4 In a laboratory batch setup, reaction of P over a catalyst was studied at various temperatures. The reactions occurring are P → 2Q; P → R At the end of one hour of operation, the batch contains x_P, xx_Q and xx_R mole fractions of P, Q and R components, respectively. The mole fractions of product components ( x_Q and x_R )were found to vary linearly with temperature as given in the figure.

If the yield of Q based on reactant P consumer ( Y_Q ) at 25 ⁰C was founded to be 0.40. Then the value of ( Y_Q ) at 60 ⁰C is................(rounded off to second decimal place).

Q. 5 Hydrogenation of benzene is to be carried out using N_i (density = 8910 kg/ m³ ) as catalyst, cast in the form of non-porous hollow cylinders, as shown below. The reaction occurs on all the surfaces of the hollow cylinder. During an experiment, one such cylinder is suspended in the reactant stream. If the observed rate of reaction is 0.39 mol ( m² of catalyst surface)^-1 min^-1 then the rate of reaction in mol(kg of catalyst)^-1 min^-1 is .................. (rounded off to three decimal places).

Q. 6 A CSTR and a PFR of equal volume are connected in series as shown below to carry out a firstorder, isothermal, liquid phase reaction.
A → P

The rate constant is 0.2 s^-1. The space-time is 5s for both the reactors. The overall fractional conversion of A is .......................(rounded off to third decimal place.)

Q. 7 A set of standard stainless steel pipes, each of internal diameter 26.65 mm and 6000 mm length, is used to make a plug flow reactor by joining them in series to carry out degradation of polyethylene. Seven such pipes are required to obtain a conversion of 66% at 450 K. The minimum number of standard 8000 mm long pipes of the same internal diameter to be procured for obtaining at least 66% conversion under the same reaction conditions is.