Combined Feed Heat Exchanger Fouling
Combined Feed Heat Exchanger Fouling
(OP)
Hi!
We have a Welded Plate Heat Exchanger (Packinox, Combine Feed Heat Exchanger) in our Continuous Catalyst Regeneration Unit (CCRU). We have long been experiencing increased Hot Approach Temperature in the exchanger and we already chemically cleaned it (2 years ago) with soda ash since we suspected that the foulant is ammonium chloride. However, we did not see any improvement in the duty of Packinox since then. What could most propbably have fouled the Packinox? And how can we address them?
Thank you very much!
We have a Welded Plate Heat Exchanger (Packinox, Combine Feed Heat Exchanger) in our Continuous Catalyst Regeneration Unit (CCRU). We have long been experiencing increased Hot Approach Temperature in the exchanger and we already chemically cleaned it (2 years ago) with soda ash since we suspected that the foulant is ammonium chloride. However, we did not see any improvement in the duty of Packinox since then. What could most propbably have fouled the Packinox? And how can we address them?
Thank you very much!





RE: Combined Feed Heat Exchanger Fouling
RE: Combined Feed Heat Exchanger Fouling
From your experience, what chemical was used for soaking and was the foulant identified? If so, what was it?
Thanks in advance.
RE: Combined Feed Heat Exchanger Fouling
RE: Combined Feed Heat Exchanger Fouling
RE: Combined Feed Heat Exchanger Fouling
Unfortunately, too often, every one puts their fudge factors on things, PHE's included during the design process so that when they get installed they are way over sized.
Doubly unfortunately for you, with a PHE, you can remove enough plates to get the velocity up into the range where it is "happy", but in your case, depending on just exactly what you mean by "welded plate", that might not be possible.
Check with the manufacturer and see what flow they recommend through this unit and if you can alter your process in any way in order to get it, make the necessary changes.
rmw
RE: Combined Feed Heat Exchanger Fouling
My recommendation: change to a gasketed PHE.
RE: Combined Feed Heat Exchanger Fouling
Now for the solution your managers are not going to like. You are going to have to spend more money on catalyst. At the start of your run you need to maximize temperatures to convert ALL the nitrogen and sulfur. As your conversion start to drift down you will have to change out your catalyst. If you do this then you have fewer issues. Alternativly you need to get better control on your Chloride addition. As catalyst ages it will take up chloride at varying rates. You will have to determine what these rates are.
RE: Combined Feed Heat Exchanger Fouling
Offshore Engineering&Design
RE: Combined Feed Heat Exchanger Fouling
Or was it designed, selected and purchase for it's current service ?
RE: Combined Feed Heat Exchanger Fouling
@MJCronin: It's designed, selected and purchased for the current service. :)
RE: Combined Feed Heat Exchanger Fouling
Just review
Using KMnO4(Potassium PerManganate) Weak Concentration Solution it may prove good cleaning solution.
Or try Orange peel/ skin uniform lowest possible viscosity slurry use as cleansing agent!
Kindly do review the process conditions for
any trace unnoticeable air or oxygen entry possibility into the system, since this may induce such fouling products generation
In order to ensure long sustainable service from the PHE in question.
Good luck for success.
Best Regards
Qalander(Chem)
RE: Combined Feed Heat Exchanger Fouling