TLS Online TPP Program

#Question id: 14337


A fermentation broth with viscosity 10 −2 Pa s and density 1000 kg m − 3 is agitated in a 2.7 m^ 3 baffled tank using a Rushton turbine with diameter 0.5 m and stirred speed 1 s ^−1. Estimate the mixing time.

#Section 5: Bioprocess Engineering and Process Biotechnology
  1. 32.4 s 
  2. 15.0 s
  3. 66.7 s
  4. 25.5 s 
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TLS Online TPP Program

#Question id: 14225

#Section 5: Bioprocess Engineering and Process Biotechnology

A fermenter is maintained at 35⁰C by water circulating at a rate of 0.5 kg s^-1 in a cooling coil inside the vessel. The inlet and outlet temperatures of the water are 8⁰C and 15⁰C respectively. The length of the cooling coil is increased by 50%. In order to maintain the same fermentation temperature, the rate of heat removal must be kept the same. Determine the new cooling-water flow rate and outlet temperature by carrying out the following calculations. The heat capacity of the cooling water can be taken as 4.18 kJ kg^- 1 o C^- 1. From a steady-state energy balance on the cooling water, calculate the rate of cooling with the original coil ___________________.

TLS Online TPP Program

#Question id: 14226

#Section 5: Bioprocess Engineering and Process Biotechnology

A fermenter is maintained at 35⁰C by water circulating at a rate of 0.5 kg s^-1 in a cooling coil inside the vessel. The inlet and outlet temperatures of the water are 8⁰C and 15⁰C respectively. The length of the cooling coil is increased by 50%. In order to maintain the same fermentation temperature, the rate of heat removal must be kept the same. Determine the new cooling-water flow rate and outlet temperature by carrying out the following calculations. The heat capacity of the cooling water can be taken as 4.18 kJ kg^- 1 o C^- 1. Determine the mean temperature difference with the original coil.

TLS Online TPP Program

#Question id: 14227

#Section 5: Bioprocess Engineering and Process Biotechnology

A fermenter is maintained at 35⁰C by water circulating at a rate of 0.5 kg s^-1 in a cooling coil inside the vessel. The inlet and outlet temperatures of the water are 8⁰C and 15⁰C respectively. The length of the cooling coil is increased by 50%. In order to maintain the same fermentation temperature, the rate of heat removal must be kept the same. Determine the new cooling-water flow rate and outlet temperature by carrying out the following calculations. The heat capacity of the cooling water can be taken as 4.18 kJ kg^- 1 o C^- 1. Evaluate UA for the original coil. ________________

TLS Online TPP Program

#Question id: 14228

#Section 5: Bioprocess Engineering and Process Biotechnology

A fermenter is maintained at 35⁰C by water circulating at a rate of 0.5 kg s^-1 in a cooling coil inside the vessel. The inlet and outlet temperatures of the water are 8⁰C and 15⁰C respectively. The length of the cooling coil is increased by 50%. In order to maintain the same fermentation temperature, the rate of heat removal must be kept the same. Determine the new cooling-water flow rate and outlet temperature by carrying out the following calculations. The heat capacity of the cooling water can be taken as 4.18 kJ kg^- 1 o C^- 1. If the length of the coil is increased by 50⁰C the area available for heat transfer, A ', also increases by 50% so that A' = 1.5 A. The value of the overall heat-transfer coefficient is not expected to change very much. For the new coil, what is the value of UA’  ______________

TLS Online TPP Program

#Question id: 14229

#Section 5: Bioprocess Engineering and Process Biotechnology

A fermenter is maintained at 35⁰C by water circulating at a rate of 0.5 kg s^-1 in a cooling coil inside the vessel. The inlet and outlet temperatures of the water are 8⁰C and 15⁰C respectively. The length of the cooling coil is increased by 50%. In order to maintain the same fermentation temperature, the rate of heat removal must be kept the same. Determine the new cooling-water flow rate and outlet temperature by carrying out the following calculations. The heat capacity of the cooling water can be taken as 4.18 kJ kg^- 1 o C^- 1. By how much are the cooling-water requirements reduced after the new coil is installed?_____________

TLS Online TPP Program

#Question id: 14230

#Section 5: Bioprocess Engineering and Process Biotechnology

In current service, 20 kg s^-1 cooling water at 12⁰C must be circulated through a coil inside a fermenter to maintain the temperature at 37⁰C The coil is 150 m long with pipe diameter 12 cm; the exit water temperature is 28⁰C After the inner and outer surfaces of the coil are cleaned it is found that only 13 kg s^-1 cooling water is required to control the fermentation temperature. Calculate the overall heat-transfer coefficient before cleaning. _____________