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This quiz contains multiple-choice problems on pore diffusion resistance.
Which of the following represents the dispersion number? (where D is the fluid dispersion coefficient, L is the length of the tracer spread, and u is the fluid velocity)?
L/(u.D)
L/D
D/(u.L)
(L.u)/D
The value of the dispersion coefficient for plug flow is
1
0
∞
2
Which of the following represents the Péclet number?
(L.u)/D
u/D
u/(D.L)
D/(u.L)
The value of the Péclet number for CSTR is
1
0
∞
2
The dispersion model is a
Two-parameter model
One-parameter model
No parameter model
Three-parameter model
The range of dispersion number for PFR is
D/(u.L) < 0.1
D/(u.L) < 0.01
D/(u.L) > 1
D/(u.L) > 10
The dispersion model accounts for
Deviation from ideal PFR
Modelling ideal CSTR
Combining batch and CSTR
CSTRs connected in parallel
If Da is diffusivity, CT is tracer concentration, and UT is overall heat transfer coefficient, the pulse tracer balance with dispersion is obtained as
∂^2.C{T}}/∂z^2 – (∂U.C{T})/∂z = ∂C{T}/∂z
D{a}.(∂^2.C{T}}/∂z^2 – (∂U.C{T})/∂z = ∂C{T}/∂z)
D{a}.(∂^2.C{T}}/∂z^2 + (∂U.C{T})/∂z = ∂C{T}/∂z)
∂^2.C{T}}/∂z^2 + (∂U.C{T})/∂z = ∂C{T}/∂z
The species continuity equation for the axial dispersion model is
u.(∂C{A}/∂z) = (∂D{a}/∂z).(∂C{A}/∂z) + (r{A})C
u(∂C{A}/∂z) = (∂D{a}/∂z).(∂C{A}/∂z) + C
∂C{A}/∂z = (∂D{a}/∂z).(∂C{A}/∂z) + (r{A})C
u.(∂C{A}/∂z) = (∂D{a}/∂z).(∂C{A}/∂z) + r{A}
The range of reactor Péclet number for open tubes is of power
10^6
10^10
10^2
10^3
