Ashell and tube exchanger is used to pre-heat the reformer feed stream, with single shell pass and 4 tube passes. the exchanger is 10 m long with a 2 m diameter, and tubes have an outer diameter of 19 mm, are 0.109 in thick, and are made from aisi 302 stainless steel. hvn is pre-heated from 95°c to 150°c at a flowrate of 90 m3 /hr, by passing through the shell side (also aisi 302). the exchanger is known as a feed-effluent exchanger because the feed stream is pre-heated with heat extracted from the effluent leaving the reformer at 280 °c. for the purposes of this assignment, you can assume that hvn has the properties of unused engine oil, as per table a-13, cengel. the nature of hvn means that the heat exchanger is subject to fouling.

a) what is the required duty of this exchanger? (12 marks)

b) determine the tube exit temperature. (3 marks)

c) estimate the heat transfer coefficients (h, w/m2 k) for i) the shell-side fluid and ii) the tube-side fluid. (9 marks)

d) calculate ua (w/k) for the exchanger (4 marks)

e) determine the number of tubes required for the heat exchanger