2 replies to this topic

[Tommy]

Dear all,

I have the following question:

Considering a shell and tube heat exchanger (BFU type), what happens if there is an inlet shell pressure change?
In particular if the shell side fluid is sea water at 15°C and the heat exchanger has been sized for a flow of 87000 kg/h at 5.3 barg, could happens some changes in heat exchange if the same fluid with the same flow is sent at 2 barg?

Thanks
Tommy

[hduncan8943]

Tommy,
If you were working with a gas, then an increase in pressure usually increases the heat transfer coefficient. Since your working with a liquid, I wouldn't expect to see any change in the coefficient by increasing the pressure.

[David Southall]

It shouldn't have much effect on the liquid properties. If you were boiling the water, you would elevate the boiling point accordingly, and lose some latent heat transfer in favour of sensible heat transfer, but I'm assuming the water remains liquid here?

Remember to spec the design pressure for the worst case in terms of your pressure fluctations, i.e. spec the design pressure with the highest operating pressure in mind.