Question

You are working in a company that has developed a process to produce DNA vaccines from E. coli. After the fermentation step a lysis step is used to release the DNA from the cells resulting in a viscous mixture. You find that an aggressive cleaning solution heated to 80°C is required to clean the sticky mixture off the inside of the lysis tank. A countercurrent shell-and-tube heat exchanger containing 100 tubes is used to heat the cleaning solution from 10 C to 80°C at a mass flow rate of 8.6 kgs-1. The tubes have external and internal diameters of 11 mm and 10 mm, respectively, and a thermal conductivity of 17 W m-I K-I . Water enters the shell at 90°C at a mass flow rate of 22 kgs-1. The shell side heat transfer coefficient is 2500 W m­2 K-1

You are given the following data: The following correlation appliesfor turbulentflow in pipes: Nu = 0.023 Re^o.8 Pr^0.4 . Cleaning Solution: Thermal conductivity = 0.5 Wm-1 K-1 Viscosity = 1 x 10-3 Pa s Specific heat capacity = 3.68 kJ kg-l K 1 Density = 1,100 kg m­3 Water Specific heat capacity = 4.18 kJ kg-l KCalculate the surface area available inside the heat exchanger.

Answer 1

Answer is explained in attachment

Thank you