2 replies to this topic

[vinay]

Dear Friends,

I have come across a problem where i have to not only calculate the fouling in shell & tube heat exchanger but also have to pin point which side (shell/tube) is fouled . I know how to calculate overall heat transfer & can determine the extent of fouling but don't know how to pin point which side is fouled , Can someone help me in this matter ?

Thanks & best regards,

Vinay

[djack77494]

Vinay,
Your need sounds very strange. I don't see the need to pinpoint the fouling. However, if you can take the exchanger off-line, you might be able to flush or chemically clean or even mechanically clean one side of the exchanger to see how that affects the performance. (Also, don't neglect a visual inspection.) Of course, not knowing what your constraints are, it is hard to suggest an approach. Something like what I've suggested could work out fine or it could be totally outside the realm of reality. While pressure drop could be an indicator, I'd suspect that by the time any hydraulic changes became noticable, the heat transfer would be just about gone. For a large continuous process where "off-line experimentation" might not be possible, you might still be able to, for instance, inject anti-fouling chemicals as a test to determine the problem. If chemical treatment proved effective on one side of the exchanger, that would imply that fouling was occurring on that side. Merely increasing the flowrate to one side of the exchanger could give an indication of the problem. Look at the "U" values at higher and lower flowrates. If you can improve U by increasing flow, you are reducing the heat transfer resistance. That could (or could not) be due to fouling. Having historical data, and especially clean exchanger data present would be helpful.
Good Luck,
Doug