Q. An azeotropic mixture of ethanol and water is to be separated in a distillation column using benzene as an entrainer. At the column operating conditions, two liquid phases are formed on a tray. The degree(s) of freedom of the system for the choice of intensive properties at equilibrium is(are) Ans: 1 to 1 […]
Q. A fiberboard sheet (1.5 m × 2.0 m × 15 mm) is being dried by suspending it horizontally in a current of hot, dry air. The edges are insulated so that drying takes place only from the top and bottom surfaces. The wet sheet weighing 16 kg with initial moisture content of 60% loses
Q. A binary distillation column is designed by McCabe-Thiele method to get a distillate mole fraction of 0.9. The enriching section operating line has an intercept with y-axis at 0.3 mole fraction. The ratio of liquid to vapour molar flow rate in the enriching section is Ans: 0.65 to 0.68
Q. It is decided to extract A from a feed containing 20 mol% A and 80 mol% B in two ideal cross-current stages as shown below, using equal amount of pure solvent C in each stage. Components B and C are immiscible. 60% of A in the feed is extracted in Stage 1. The equilibrium
Q. 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
Q. A CSTR and a PFR of equal volume are connected in series as shown below to carry out a first-order, isothermal, liquid phase reaction The rate constant is 0.2 s-1. The space-time is 5 s for both the reactors. The overall fractional conversion of A is Ans: 0.80 to 0.84
Q. At a shear rate of 10 s-1, the apparent viscosity of a non-Newtonian liquid was found to be 1 Pa s. At a shear rate of 100 s-1, the apparent viscosity of the same liquid was found to be 0.5 Pa s. If the liquid follows power law behavior, the apparent viscosity (in Pa
Q. Under isothermal condition, a vertical tube of length L = 100 m contains a gas of molecular weight equal to 60. The pressure and temperature at the top of the tube are 100 kPa and 25 oC respectively. Consider the universal gas constant and acceleration due to gravity as 8.314 J mol-1 K-1 and
Q. Vapour bubbles are formed in the nucleate boiling regime at a frequency of 10 bubbles per second per nucleation site. There are 100 nucleation sites per m2 of heating area. The latent heat of vapourization and the density of vapour under the operating condition are 1000 kJ/kg and 1 kg/m3 respectively. The diameter of
Q. The wall of a pipe of radius 1 m is at a uniform temperature of 200 oC, and is covered by insulation of thickness 0.1 m. The ambient air outside the insulated pipe is at 20 oC and has heat transfer coefficient of 10 W m-2 K-1. The thermal conductivity of the insulation material
