Distillation Design Multiple Choice Questions & Answers (MCQs) on “Extractive Distillation”.
1. The crucial difference compared to homozeotrope distillation is that, a heteroazeotrope can be separated by?
a) Decantation
b) Depurification
c) Dehydration
d) Decansing
Answer: a
Clarification: The crucial difference compared to homoazeotropic distillation is that a heteroazeotrope can be separated easily by decantation, this also makes the process scheme simpler.
2. Which of the following equations are satisfied at azeotropic conditions?
a) Av(v) + Al(v) = 0
b) Av(v) – Al(v) = 0
c) Av(v). Al(v) = 0
d) Av(v) =Al(v)
Answer: b
Clarification: Av(v) and Al(v) are the Helmholtz energy of the vapor and liquid phases respectively, V, V0 and Vl are the total molar volume.
3. The residue curves of an n component homogenous mixture is defined by?
a) n-1 ODE
b) n-2 ODE
c) n-3 ODE
d) n ODE
Answer: a
Clarification: The residue curves of an n component homogenous mixture is defined by n-1 ODE’s, where dxi/dE and E is dimensionless warped time.
4. Permeate fluxes decrease, significantly with decreasing
a) Reflux ratio
b) Feed Concentrations
c) Boiling point
d) Bubble point
Answer: b
Clarification: Permeate fluxes decrease significantly with decreasing feed concentrations, There is a trade-off between the permeate flux and selectivity.
5. Heteroazeotropic (VLLE) distillation, often referred to as?
a) Azeotropic distillation
b) Exractive distilllaton
c) Batch Ditilation
d) Continous Distillation
Answer: a
Clarification: Heteroazeotropic (VLLE) distillation, often referred to as azeotropic distillation, involves the formation of a heteroazeotrope to affect the desired separation.
6. A greater entrainer flowrate generally, yields better
a) Reflux
b) Boil up
c) Hold up
d) Separation
Answer: d
Clarification: A greater entrainer flowrate generally yields better separation, but this increases the energy demand in both columns and increases the reboiler temperature in the extractive column.
7. Separating a maximum-boiling azeotrope using a light entrainer, this process is referred to as?
a) Re-extractive distillation
b) De-extractive distillation
c) Extractive distillation
d) Boil up distillation
Answer: a
Clarification: The same extractive distillation scheme can in principle be applied to the symmetrical system of
separating a maximum-boiling azeotrope using a light entrainer and this process is referred to as re-extractive distillation.
8. The vapor-liquid equilibrium (VLE) condition which may be expressed as?
a) y = f (S, H, T)
b) y = f (P, T, x)
c) x = f (T, S)
d) y = f (J, S)
Answer: b
Clarification: Where x and y are the liquid and vapor compositions, and P and T are the system pressure and temperature, respectively T and x are not independent at the equilibrium state.
9. When y = E(x), where E is?
a) Mapping function
b) Entity function
c) Frequency function
d) Phase function
Answer: a
Clarification: E is the equilibrium mapping function that assigns a composition in the liquid phase to the corresponding equilibrium vapor phase composition, and Tbp and Tdp are the mixture boiling temperature.
10. When x = C(y), where C is?
a) Inverse function
b) Mapping function
c) Entrainment function
d) Flooding Function
Answer: a
Clarification: Here, C is the inverse equilibrium mapping function that assigns a composition in the vapor phase to the corresponding equilibrium liquid phase composition.