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# Distillation Design MCQ’s – Stratergy of Solution using Rigorous Methods

The Wang Henke equation is used, for the calculation of

a) Flow rates

b) Volatility

c) Stages

d) Reflux

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Answer: a

Explanation: The Wang Henke equation is used for the calculation of component and flow rates, Fenske’s for relative volatility and material balance for flow rates.

Wide boiling and energy coupled systems are drastically

a) Exponential

b) Linear

c) Logarithmic

d) Semi logical

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Answer: b

Explanation: Wide boiling and energy coupled systems are drastically Linear, while d/b plots are nonlinear and equilibrium plots are also nonlinear.

Difference between k and k+1 should be very

a) Small

b) Large

c) Zero

d) Unity

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Answer: a

Explanation: Difference between k and k+1 should be very small, if the difference increases this could cause problems like stage failure and flooding.

Rigorous method are based on?

a) Heat duties

b) Product compositions

c) Feed tares

d) Stages

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Answer: a

Explanation: Rigorous method are based on Heat duties and other methods are based on the feed and Product compositions.

MESH equations are written in terms of?

a) Mass rates

b) Flow rates

c) Vapor rates

d) Liquid rate

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Answer: c

Explanation: MESH equations are written in terms of Vapor rates and material balance equations are written in mass and flow rates.

In matrix form, system equation is expressed as

a) r_{i}v_{i} = -f_{j}

b) r_{i}v_{i} = -K_{j}

c) r_{i}v_{i} = -G_{j}

d) r_{i}v_{i} = -Z_{j}

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Answer: a

Explanation: In matrix form system equation is expressed as r_{i}v_{i} = -f_{j}, where f is the function of the matrix and r_{i} and v_{i} are rows and columns.

The transposed vapor rate vector, V_{i} is raised to power of

a) J_{k}

b) I_{k}

c) T

d) P

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Answer: c

Explanation: As V_{i} = (di, vi1, vi2, vi_{N}) ^{T} So T is Power, here T represents the temperature on which the vapor rate is measured.

The transposed feed Rate vector, is proportional to

a) T

b) G

c) K

d) P

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Answer: a

Explanation: f_{j} = (0, 0, 0……Vi…0, 0)^{T} So T is Power of the function and the zero represents the empty states in the function.

The adiabatic split of vapor and liquid portion are expressed as

a) V_{If} and L_{iF}

b) K_{If} and L_{iF}

c) V_{If} and K_{iF}

d) X_{If} and Y_{iF}

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Answer: c

Explanation: The adiabatic split of vapor and liquid portion are expressed as V_{If} and L_{If}, These are equally important for all compositions of vapor and liquid.

. The main diagonal mij is expressed as

a) –(1+A_{ij})

b) -(A_{ij})

c) 1-A_{ij}

d) A_{ij}

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Answer: a

Explanation: Here m_{ij}=–(1+A_{ij}) for any stage j, while -(A_{ij}) represent only the factor for both gas and liquid phases and negative sign indicates the decreasing slope.