Make a preliminary mechanical design for the vertical thermosyphon reboiler for which the thermal design was given in Example 12.10 in Chapter 12. The inlet liquid nozzle and the steam connections will be 50mm inside diameter. Flat plate end closures will be used on both headers. The reboiler will be hung from four bracket supports, positioned 0.5m down from the top tube plate. The shell and tubes will be of semi-killed carbon steel. Your design should cover:

(a) Choice of design pressure and temperature,

(b) Choice of the required corrosion allowances,

(c) Selection of the header dimensions.

(d) Determination of the minimum wall thickness for the shell, headers and ends,

(e) A check on the pressure rating of the tubes.

Data from example 12.10

Make a preliminary design for a vertical thermosyphon for a column distilling crude aniline. The column will operate at atmospheric pressure and a vaporization rate of 6000 kg/h is required. Steam is available at 22 bar (300 psig). Take the column bottom pressure as 1.2 bar.