tube failure in Heat exchanger
tube failure in Heat exchanger
(OP)
Dear sir,
pls let me ask you some technical advice for tube failure in Heat exchanger.
as shown on attached Tube failure status.
I would like to know that why 8~10 q'ty yearly tube failure occured in 3, 4 pass area near by
Condensate drain nozzle that is by 2nd baffle from Tube sheet especially
since 15 year operation.
1. Tube OD 19.05, thk 1.65mm
2. Shell Side Flash Vapor : 0.3% of Terephthalic Acid contained Water, Condensate water
pH 3.8
3. Tube side : Reactor Feed
4. Material : Shell-SS304L, Tube-SS316L
5. Tube side Pass ; 4 pass
6. Tube failure major status : Founded Pitting and Crack assumed by SCC
(Stress and Corrosion Cracking) at tube outside surface.
7. Pls see attached reference status
Could you advise me of your technical opinion in this regard.
Kind regards,
Ryu Chang
pls let me ask you some technical advice for tube failure in Heat exchanger.
as shown on attached Tube failure status.
I would like to know that why 8~10 q'ty yearly tube failure occured in 3, 4 pass area near by
Condensate drain nozzle that is by 2nd baffle from Tube sheet especially
since 15 year operation.
1. Tube OD 19.05, thk 1.65mm
2. Shell Side Flash Vapor : 0.3% of Terephthalic Acid contained Water, Condensate water
pH 3.8
3. Tube side : Reactor Feed
4. Material : Shell-SS304L, Tube-SS316L
5. Tube side Pass ; 4 pass
6. Tube failure major status : Founded Pitting and Crack assumed by SCC
(Stress and Corrosion Cracking) at tube outside surface.
7. Pls see attached reference status
Could you advise me of your technical opinion in this regard.
Kind regards,
Ryu Chang





RE: tube failure in Heat exchanger
"If you don't have time to do the job right the first time, when are you going to find time to repair it?"
RE: tube failure in Heat exchanger
"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick
RE: tube failure in Heat exchanger
RE: tube failure in Heat exchanger
With the location of these failures local variations in Temp and/or flow look like issues.
This may be a design issue, or you ma be operating outside of the design range.
As far as I am concerned in place ECT is worthless unless you are pulling tubes for lab analysis.
I have seen pit depth calls off by a factor of 5 (both over and under) based on standards used.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube
RE: tube failure in Heat exchanger
Most of Tube damage occured 3 Pass and 4 Pass area at condensate Drain nozzle where rear tube sheet
to 2ND baffle especially, this is issue why this area damaged rather than other zone.
at the moment, this is related to operating level of condensate water. and due to corrosion compound
when chemical cleaning.
Lab inspection repor for sample tube summarized as follows.
1. Major damage : Pitting and Stress Corrosion Cracking
2. Tube surface crack into tube inside : 1.1mm and growing slowly
3. Most damage area : It occured at back side of Tube sheet (2ND baffle area)
in 3 pass and 4 Pass zone in a length of 600mm.
Also,Scale cluster founded this area.
4. It founded S,Cl,Na at damage tube as corrosion factor. Chloride 0.75~0.99Wt%
RE: tube failure in Heat exchanger
RE: tube failure in Heat exchanger
RE: tube failure in Heat exchanger
"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick