1.
a) For the following three shell-and-tube heat exchanger applications,
state which fluid you would allocate to the shell side and which to the
tube side, giving reasons in each case. Except where stated otherwise,
in each scenario below, assume corrosion and fouling are unlikely to
occur and that the film coefficients of heat transfer are likely to be
similar for each stream. None of the fluids are at very high
temperatures.
i) A process fluid is to be heated from 25°C to 60°C at high pressure
by a service fluid at 3 bar.
[2 marks]
ii) A process stream at 3 bar is to be cooled from 60°C to 30°C using
a corrosive service fluid also at 3 bar.
[2 marks]
iii) A process fluid at atmospheric pressure is to be cooled from 70°C
to 40°C using a service fluid at the same pressure. The service
fluid is expected to give rise to a much higher film coefficient of
heat transfer than the process fluid.
[2 marks]
b) Explain what is meant by the term 'fouling resistance' in the context of
heat transfer in shell-and-tube heat exchangers. How is this effect
accounted for in the design of such heat exchangers?
[4 marks]
