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From the corrosion point of view, would it help in improving the performance if vertical exchanger is provided in the crude overhead circuit? Comment on self-draining of the shock condensation, effect on deposit built up and water wash performance? Suggest preferable design of the heat exchanger?
 
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02/02/2015 A: Eric Vetters, ProCorr Consulting Services, ewvetters@yahoo.com
For overhead systems using a water wash, a vertical exchanger with the overhead on the tubeside can be advantageous. With the proper water wash location, the vertical configuration makes it easier to get water to all the tubes thus providing much more uniform performance. Condensation will drain down the inner wall of the tube instead of dripping onto the tube below, but I don't see that as a particular benefit. The improved water wash distribution minimizes the risk of salt formation and subsequent tube plugging from salt build up.
A vertical exchanger in this service is typically a single tube pass (multiple tube passes would increase DP significantly and could lead to flow instability from trying to push the condensate uphill in the even number tube passes). Mechanical design of such exchangers can be tricky. Depending on the delta T across the exchanger an expansion joint in the shell may be required.