5. Ethyl alcohol (specific heat capacity = 3840 1 kg ¹K¹) at a flowrate of 30,000 kg h is to be cooled from 78°C to 44°C

[answerhappygod]

5 Ethyl Alcohol Specific Heat Capacity 3840 1 Kg K At A Flowrate Of 30 000 Kg H Is To Be Cooled From 78 C To 44 C 1 (78.81 KiB) Viewed 41 times

5. Ethyl alcohol (specific heat capacity = 3840 1 kg ¹K¹) at a flowrate of 30,000 kg h is to be cooled from 78°C to 44°C. A one shell pass, two tube pass heat exchanger is available, consisting of 35 tubes in each pass. The tubes are made of stainless steel (thermal conductivity = 19 W m-¹ K-¹), each of 33 mm external diameter, 26 mm internal diameter, with a total length over the two passes of 15 m. Cooling water (specific heat capacity= 4179 J kg ¹ K-¹) is available at 9°C and a flowrate of 24665 kg/hour. (a) Calculate the exit temperature of the cooling water. Draw and label a temperature. enthalpy diagram for the system. (b) The water is to flow through the 35 tubes on the tube side of the heat exchanger. Using the Colburn equation, show that the convection heat transfer coefficient on the tube side is about 1700 W m2 K-¹. Find appropriate values of the thermophysical properties of water from steam tables. (c) The convection heat transfer coefficient on the shell side is 900 W m² K¹, and fouling factors on both the inside and outside of the pipes are 0.00018 m² KW. Calculate the overall heat transfer coefficient based on the outside area of the tubes. (d) Using the correction factor chart (Figure 5.1] for a one shell pass, two tube pass shell and tube heat exchanger, calculate the total surface area required. Is the available heat exchanger sufficiently large for this duty? [20 marks all together