#Question id: 14234
#Section 5: Bioprocess Engineering and Process Biotechnology
Nutrient medium is to be heated from 10⁰C to 28⁰C is a single-pass countercurrent shell-and-tube heat exchanger before being pumped into a fed-batch fermenter. Medium passes through the tubes of the exchanger; the shell-side fluid is water which enters with flow rate 3 x 10^4 kg h^- 1 and temperature 60⁰C pre-heated medium is required at a rate of 50 m^3 h^-1. The density, viscosity and heat capacity of the medium are the same as water; the thermal conductivity of the medium is 0.54 Wm^- 1 ⁰C ^- 1. It is proposed to use 30 steel tubes with inner diameter 5 cm; the tubes will be arranged in line. The pipe wall is 5-mm thick; the thermal conductivity of the metal is 50 Wm^- 1 ⁰C ^- 1. The maximum linear shell-side fluid velocity is estimated as 0.15 m s^-1. Calculate the log-mean temperature difference _________
#Question id: 14235
#Section 5: Bioprocess Engineering and Process Biotechnology
Nutrient medium is to be heated from 10⁰C to 28⁰C is a single-pass countercurrent shell-and-tube heat exchanger before being pumped into a fed-batch fermenter. Medium passes through the tubes of the exchanger; the shell-side fluid is water which enters with flow rate 3 x 10^4 kg h^- 1 and temperature 60⁰C pre-heated medium is required at a rate of 50 m^3 h^-1. The density, viscosity and heat capacity of the medium are the same as water; the thermal conductivity of the medium is 0.54 Wm^- 1 ⁰C^ - 1. It is proposed to use 30 steel tubes with inner diameter 5 cm; the tubes will be arranged in line. The pipe wall is 5-mm thick; the thermal conductivity of the metal is 50 Wm^- 1 ⁰C^ - 1. The maximum linear shell-side fluid velocity is estimated as 0.15 m s^-1. Determine the heat-transfer area. ____________
#Question id: 14236
#Section 5: Bioprocess Engineering and Process Biotechnology
#Question id: 14237
#Section 5: Bioprocess Engineering and Process Biotechnology
A genetically-engineered strain of yeast is cultured in a bioreactor at 30⁰C for production of heterologous protein. The oxygen requirement is 80 mmol 1-1 h-I; the critical oxygen concentration is 0.004 mM. The solubility of oxygen in the fermentation broth is estimated to be 10% lower than in water due to solute effects. What is the minimum mass-transfer coefficient necessary to sustain this culture if the reactor is sparged with air at approximately 1 atm pressure ?
#Question id: 14238
#Section 5: Bioprocess Engineering and Process Biotechnology
A genetically-engineered strain of yeast is cultured in a bioreactor at 30⁰C for production of heterologous protein. The oxygen requirement is 80 mmol 1-1 h-I; the critical oxygen concentration is 0.004 mM. The solubility of oxygen in the fermentation broth is estimated to be 10% lower than in water due to solute effects. What mass-transfer coefficient is required if pure oxygen is used instead of air?
#Question id: 14239
#Section 5: Bioprocess Engineering and Process Biotechnology
A 200-1itre stirred fermenter contains a batch culture of
Bacillus subtilis bacteria at 28⁰C Air at 20⁰C is pumped into the vessel at
a rate of 1 vvm; (vvm stands for volume of gas per volume of liquid per
minute). The average pressure in the fermenter is 1 atm. The volumetric flow
rate of off-gas from the fermenter is measured as 189 l min-1. The
exit gas stream is analysed for oxygen and is found to contain 20.1% 02.
The dissolved-oxygen concentration in the broth is measured using an oxygen
electrode as 52% air saturation. The solubility of oxygen in the fermentation
broth at 28⁰C
and 1 atm air pressure is 7.8 x 10-3 kg m-3. Calculate
the oxygen transfer rate_____________