Small food particles with diameter 10^-2 mm and density 1.03 g cm^-3 are suspended in liquid of density 1.00 g cm^-3. The viscosity of the liquid is 1.25 mPa s. A tubular-bowl centrifuge of length 70 cm and radius 11.5 cm is used to separate the particles. If the centrifuge is operated at 10 000 rpm, estimate the feed flow rate at which the food particles are just removed from the suspension. ____________________

#Question id: 14197

#Section 5: Bioprocess Engineering and Process Biotechnology

#Question id: 14198

#Section 5: Bioprocess Engineering and Process Biotechnology

which of the following do not come under continuous filtration?

#Question id: 14199

#Section 5: Bioprocess Engineering and Process Biotechnology

#Question id: 14200

#Section 5: Bioprocess Engineering and Process Biotechnology

A fluidized-bed, immobilized-cell bioreactor is used for the conversion of glucose to ethanol by Z. mobilis cells immobilized in k-carrageenan gel beads. The dimensions of the bed are 10 cm (diameter) by 200 cm. Since the reactor is fed from the bottom of the column and because of CO₂ gas evolution, substrate and cell concentrations decrease with the height of the column. The average cell concentration at the bottom of the column is X₀ = 45 g/l, and the average cell concentration decreases with the column height according to the following equation:

where Z is the column height (cm). The specific rate of substrate consumption is q_S = 2 g S/g cells . h. The feed flow rate and glucose concentration in the feed are 5 l/h and 160 g glucose/l, respectively.

Determine the ethanol concentration in the effluent (g/l . h) if YP/S = 0.48 g ethanol/g glucose

#Question id: 14201

#Section 5: Bioprocess Engineering and Process Biotechnology

A fluidized-bed, immobilized-cell bioreactor is used for the conversion of glucose to ethanol by Z. mobilis cells immobilized in k-carrageenan gel beads. The dimensions of the bed are 10 cm (diameter) by 200 cm. Since the reactor is fed from the bottom of the column and because of CO₂ gas evolution, substrate and cell concentrations decrease with the height of the column. The average cell concentration at the bottom of the column is X₀ = 45 g/l, and the average cell concentration decreases with the column height according to the following equation:

where Z is the column height (cm). The specific rate of substrate consumption is q_S = 2 g S/g cells . h. The feed flow rate and glucose concentration in the feed are 5 l/h and 160 g glucose/l, respectively.

Determine the ethanol productivity (g/l . h) if YP/S = 0.48 g ethanol/g glucose.

_______________

#Question id: 14202

#Section 5: Bioprocess Engineering and Process Biotechnology

In a fluidized-bed biofilm reactor, cells are attached on spherical plastic particles to form biofilms of average thickness L = 0.5 mm. The bed is used to remove carbon compounds from a waste-water stream. The feed flow rate and concentration of total fermentable carbon compounds in the feed are F = 2 l/h and S = 2000 mg/l. The diameter of the column is 10 cm. The kinetic constants of the microbial population are r_m = 50 mg S/cm³. h and K_S = 25 mg S/cm³ . The specific surface area of the biofilm in the reactor is 2.5 cm² /cm³ . Assuming first-order reaction kinetics and an average effectiveness factor of n = 0.7 throughout the column, determine the required height of the column for effluent total carbon concentration of S_0i = 100 mg/l.