A two-stage chemostat system is used for production of secondary metabolite. The volume of each reactor is 0.5 m³; the flow rate of feed is 50 l h^{- 1}. Mycelial growth occurs in the first reactor; the second reactor is used for product synthesis. The concentration of substrate in the feed is 10 gl^-1. Kinetic and yield parameters for the organism are:

                                                            

Assume that product synthesis is negligible in the first reactor and growth is negligible in the second reactor. Determine substrate concentrations entering the second reactor.

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#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. ________________

#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’  ______________

#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?_____________

#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. _____________

#Question id: 14231

#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. What fraction of the total resistance to heat transfer before cleaning was due to fouling deposits?____________

#Question id: 14232

#Section 5: Bioprocess Engineering and Process Biotechnology