Chemical Reaction Engineering Questions and Answers – Non Ideal Reactors – Dispersion Model

This set of Chemical Reaction Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Non Ideal Reactors – Dispersion Model”.

1. If D is the fluid dispersion coefficient, L is the length of spread of tracer and u is the fluid velocity, then which of the following represents Dispersion number?
a) \(\frac{L}{uD}\)
b) \(\frac{L}{D}\)
c) \(\frac{D}{uL}\)
d) \(\frac{Lu}{D}\)
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2. The value of the Dispersion coefficient for plug flow is ____
a) 1
b) 0
c) ∞
d) 2
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3. Which of the following represents Peclet number?
a) \(\frac{Lu}{D} \)
b) \(\frac{u}{D} \)
c) \(\frac{u}{DL} \)
d) \(\frac{D}{uL} \)
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4. The value of the Peclet number for CSTR is ____
a) 1
b) 0
c) ∞
d) 2
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5. The range of dispersion number for PFR is ____
a) \(\frac{D}{uL}\) < 0.1
b) \(\frac{D}{uL}\) < 0.01
c) \(\frac{D}{uL}\) > 1
d) \(\frac{D}{uL}\) > 10
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6. The dispersion model accounts for ____
a) Deviation from ideal PFR
b) Modelling ideal CSTR
c) Combining batch and CSTR
d) CSTRs connected in parallel
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7. The the species continuity equation for the axial dispersion model is ____
a) u \(\frac{∂C_A}{∂z} = \frac{∂D_a}{∂z} \frac{∂C_A}{∂z}\) + (r_A)C
b) u \(\frac{∂C_A}{∂z} = \frac{∂D_a}{∂z} \frac{∂C_A}{∂z}\) + C
c) \(\frac{∂C_A}{∂z} = \frac{∂D_a}{∂z} \frac{∂C_A}{∂z}\) + (r_A)C
d) u \(\frac{∂C_A}{∂z} = \frac{∂D_a}{∂z} \frac{∂C_A}{∂z}\) + (r_A)
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8. If D_a is diffusivity, C_T is tracer concentration and U_T is overall heat transfer coefficient, then the pulse tracer balance with dispersion is obtained as ____
a) \(\frac{∂^2 C_T}{∂z^2} – \frac{∂(UC_T)}{∂z} = \frac{∂C_T}{∂z} \)
b) D_a\(\frac{∂^2 C_T}{∂z^2} – \frac{∂(UC_T)}{∂z} = \frac{∂C_T}{∂z} \)
c) D_a\(\frac{∂^2 C_T}{∂z^2} + \frac{∂(UC_T)}{∂z} = \frac{∂C_T}{∂z} \)
d) D_a\(\frac{∂^2 C_T}{∂z^2} – \frac{∂(UC_T)}{∂z} = \frac{∂C_T}{∂z} \)
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9. The range of reactor peclet number for open tubes is ____
a) 10⁶
b) 10¹⁰
c) 10²
d) 10³
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10. The dispersion model is a ____
a) Two parameter model
b) One parameter model
c) No parameter model
d) Three parameter model
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Sanfoundry Global Education & Learning Series – Chemical Reaction Engineering.

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