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Biochemical Engineering

Assuming the laminar flow across the filter, the rate of filtration (dVf/dt) can be expressed as a function of pressure drop Dp by the modified D’Arcy’s equation as (where A is the area of filtering surface, K is the D’Arcy’s filter cake permeability and L is the thickness of the filter cake)

Biochemical Engineering, Downstream Processing /
Question: Assuming the laminar flow across the filter, the rate of filtration (dVf/dt) can be expressed as a function of pressure drop Dp by the modified D’Arcy’s equation as (where A is the area of filtering surface, K is the D’Arcy’s filter cake permeability and L is the thickness of the filter cake)
[A].

(1/A) dVf/dt = Δp/μ(L/K)

[B].

dVf/dt = (1/A)Δp/μ(L/K)

[C].

(1/A) dVf/dt = Δp/μ LK

[D].

dVf/dt = (1/A)Δp/μ LK

Answer: Option A

Explanation:

No answer description available for this question.

Assuming the laminar flow across the filter, the rate of filtration (dVf/dt) can be expressed as a function of pressure drop Dp by the modified D’Arcy’s equation as (where A is the area of filtering surface, K is the D’Arcy’s filter cake permeability and L is the thickness of the filter cake) Read More »

Biochemical Engineering, Downstream Processing

For aerated mixing vessels in an aqueous solution, the mass transfer coefficient (kL) co-relating power consumption (Pm) and fermenter volume (V) can be expressed as

Agitation And Aeration, Biochemical Engineering /
Question: For aerated mixing vessels in an aqueous solution, the mass transfer coefficient (kL) co-relating power consumption (Pm) and fermenter volume (V) can be expressed as
[A].

kL ∝ (Pm/V)0.33

[B].

kL ∝ (Pm/V)0.66

[C].

kL ∝ (Pm/V)0.50

[D].

kL ∝ (Pm/V)

Answer: Option A

Explanation:

No answer description available for this question.

For aerated mixing vessels in an aqueous solution, the mass transfer coefficient (kL) co-relating power consumption (Pm) and fermenter volume (V) can be expressed as Read More »

Agitation And Aeration, Biochemical Engineering

The dynamic technique is based on the

Agitation And Aeration, Biochemical Engineering /
Question: The dynamic technique is based on the
[A].

oxygen material balance in an aerated batch fermenter during the growth of microorganisms

[B].

change of the oxygen concentration

[C].

oxidation of the sodium sulfite to sodium sulfate

[D].

oxygen material balance in a fermenter

Answer: Option A

Explanation:

No answer description available for this question.

The dynamic technique is based on the Read More »

Agitation And Aeration, Biochemical Engineering

The power required by an impeller in a gas sparged system compare to the power required by impeller operating at same speed in a gas free liquid is usually

Agitation And Aeration, Biochemical Engineering /
Question: The power required by an impeller in a gas sparged system compare to the power required by impeller operating at same speed in a gas free liquid is usually
[A].

lesser

[B].

higher

[C].

same

[D].

may be lesser or higher depending upon the geometry

Answer: Option A

Explanation:

No answer description available for this question.

The power required by an impeller in a gas sparged system compare to the power required by impeller operating at same speed in a gas free liquid is usually Read More »

Agitation And Aeration, Biochemical Engineering

In a two-phase system where the continuous phase remains in place, the gas hold up can be expressed as (where Vs and Vt are the superficial gas velocity and bubble rise velocity)

Agitation And Aeration, Biochemical Engineering /
Question: In a two-phase system where the continuous phase remains in place, the gas hold up can be expressed as (where Vs and Vt are the superficial gas velocity and bubble rise velocity)
[A].

H = Vs/(Vs-Vt)

[B].

H = Vs/(Vs+ Vt)

[C].

H = Vs/(Vs.Vt)

[D].

H = (Vs+Vt)/Vs

Answer: Option B

Explanation:

No answer description available for this question.

In a two-phase system where the continuous phase remains in place, the gas hold up can be expressed as (where Vs and Vt are the superficial gas velocity and bubble rise velocity) Read More »

Agitation And Aeration, Biochemical Engineering

The average fractional gas hold up (H) can be given as (where Zf and Zl are the level of aerated and clear liquid respectively)

Agitation And Aeration, Biochemical Engineering /
Question: The average fractional gas hold up (H) can be given as (where Zf and Zl are the level of aerated and clear liquid respectively)
[A].

H = (Zf-Zl)/Zf

[B].

H = Zf/Zl

[C].

H = Zf/ZfZl

[D].

H =(Zf+Zl)/Zf

Answer: Option A

Explanation:

No answer description available for this question.

The average fractional gas hold up (H) can be given as (where Zf and Zl are the level of aerated and clear liquid respectively) Read More »

Agitation And Aeration, Biochemical Engineering

Gas hold up, characterizing the hydrodynamics in a fermenter, mainly depends on the

Agitation And Aeration, Biochemical Engineering /
Question: Gas hold up, characterizing the hydrodynamics in a fermenter, mainly depends on the
[A].

superficial gas velocity

[B].

power consumption

[C].

Both (a) and (b)

[D].

gas concentration

Answer: Option C

Explanation:

No answer description available for this question.

Gas hold up, characterizing the hydrodynamics in a fermenter, mainly depends on the Read More »

Agitation And Aeration, Biochemical Engineering

Surface renewal theory predicts that the mass transfer coefficient is

Agitation And Aeration, Biochemical Engineering /
Question: Surface renewal theory predicts that the mass transfer coefficient is
[A].

directly proportional to the square root of the molecular diffusivity

[B].

inversely proportional to the square root of the molecular diffusivity

[C].

directly proportional to the cube root of the molecular diffusivity

[D].

indirectly proportional to the cube root of the molecular diffusivity

Answer: Option A

Explanation:

No answer description available for this question.

Surface renewal theory predicts that the mass transfer coefficient is Read More »

Agitation And Aeration, Biochemical Engineering

Penetration theory assumes that turbulent eddies travel from the bulk of the phase to the interface where they remain constant for a constant exposure time (te). The model correlating KL, mass transfer coefficient and DAB, diffusivity can be expressed as

Agitation And Aeration, Biochemical Engineering /
Question: Penetration theory assumes that turbulent eddies travel from the bulk of the phase to the interface where they remain constant for a constant exposure time (te). The model correlating KL, mass transfer coefficient and DAB, diffusivity can be expressed as
[A].

KL = 2(DAB/πte)0.25

[B].

KL = 2(DAB/πte)0.5

[C].

KL = 2(DAB/πte)0.75

[D].

KL = 2(DAB/πte)

Answer: Option B

Explanation:

No answer description available for this question.

Penetration theory assumes that turbulent eddies travel from the bulk of the phase to the interface where they remain constant for a constant exposure time (te). The model correlating KL, mass transfer coefficient and DAB, diffusivity can be expressed as Read More »

Agitation And Aeration, Biochemical Engineering