Question 3 (a) Waste dairy whey is used to grow Kluyveromyces fragilis yeast in a continuous culture system operated at 30C and 1 atm pressure. Medium containing 4% w/w lactose (C12H22011) and 0.15% w/w NH3 flows into a specially designed aerated bioreactor at a rate of 200 kg/h. The reactor is compartmentalised to facilitate gravity settling of the yeast; a suspension containing concentrated cells is drawn off continuously from the bottom of the reactor at a rate of 40 kg/h, while an aqueous waste stream containing 0.5 kg cells per 100 kg leaves from the top. All of the lactose provided is utilised by the culture. The biomass yield from lactose is known from preliminary experiments to be 0.25 g/g. The composition of the K. fragilis biomass is determined by elemental analysis to be CH1630.5 No.16 +7.5% ash. (0) State the characteristic of waste dairy whey and Kluyveromyces fragilis yeast as culture medium. (4 marks) (ii) In a cold climate, the fermenter must be kept at 35C. After considering the oxygen demand, the maximum heat transfer rate required is estimated as 550 kW. Cooling water available at 10C, the exit temperature of 25C. The heat transfer coefficient for the culture system is estimated as 2150 W/m2C. Outer diameter of the pipe is 8cm, with fouling factor of 8500 W/m2C. (a) State Cp value for water and refrigerant 134a. (2 marks) (b) Determine the log mean temperature difference of the heat exchanger. (4 marks) (c) Estimate the length of the pipe required