ceramic coating of CS heat exchanger bonnet internals
ceramic coating of CS heat exchanger bonnet internals
(OP)
Dear All,
Sorry for laziness - I didnt do due diligence on researching this subject. I hope members would be forgiving and kind enough to provide useful tips.
We are going to apply ceramic coating for internals of CS bonnets of our sea water exchangers. I want to know if any special precaution/ care needs to be taken for this.
1) Is there any standard/ specification which governs such a coating. If there is one then I surely wont have it, so I would appreciate if you could give a summary of it in this post :)
2) ARe there different grades of ceramics coatings? WHich is the best?
3) What test/ inspection to be done to ensure cermic coating is good.
4) We plan to operate these exchangers, uninterrupted, for 5 years. After this duration, is it recommended to re-coat the ceramic? How to ascertain whether any partial damage has occured or not?
5) Is there any external non-invasive NDT test that can be carried out by our plant maintenance people (say once every 1 year) to ensure that the ceramic coating is "intact" and has not flaked/ peeled/ eroded?
Regards
Sorry for laziness - I didnt do due diligence on researching this subject. I hope members would be forgiving and kind enough to provide useful tips.
We are going to apply ceramic coating for internals of CS bonnets of our sea water exchangers. I want to know if any special precaution/ care needs to be taken for this.
1) Is there any standard/ specification which governs such a coating. If there is one then I surely wont have it, so I would appreciate if you could give a summary of it in this post :)
2) ARe there different grades of ceramics coatings? WHich is the best?
3) What test/ inspection to be done to ensure cermic coating is good.
4) We plan to operate these exchangers, uninterrupted, for 5 years. After this duration, is it recommended to re-coat the ceramic? How to ascertain whether any partial damage has occured or not?
5) Is there any external non-invasive NDT test that can be carried out by our plant maintenance people (say once every 1 year) to ensure that the ceramic coating is "intact" and has not flaked/ peeled/ eroded?
Regards





RE: ceramic coating of CS heat exchanger bonnet internals
Anyone having experience with HVOF ceramics in industrial environment (Refiner, petrochemicals, etc). Is it cost effective to do it.
I received some quotations for the bonnets. The vendors are proposing the following coating method:
grit blast to SA2-1/2, and apply two coats of 250 microns each of EPIGEN 806BR; ie a total of 500 microns.
Is this a reliable coating? Compared to HVOF ceramic coating how does this coating stand?
Regards
RE: ceramic coating of CS heat exchanger bonnet internals
For most liquid applications, it may be better (less porous) than HVOF-applied ceramics. However, it is limited temperature-wise:
"Maximum exposure temperature, 125oC.
Heat deflection temperature ASTM D648, 80oC."
from Tech data available at http://www.epigen.com.au/
I suggest contacting their technical support with your application specifics.
I am unaware of any standard for ceramic-coated seawater HXers. HVOF ceramics are rougher & (I expect) will generally foul more rapidly than metals or plastic coatings. There are very slick plasma-applied ceramics, http://www.sub-one.com/breakthrough.html, but I have no first-hand experience.
I suggest a titanium or Ni-based alloy HXer for best chance at operating 5 years uninterrupted. Is abrasion resistance (due to sandy conditions) required? What maintenance will you be doing (periodic dosing with acids, biocides, etc.)?
RE: ceramic coating of CS heat exchanger bonnet internals
RE: ceramic coating of CS heat exchanger bonnet internals
Regards
RE: ceramic coating of CS heat exchanger bonnet internals
RE: ceramic coating of CS heat exchanger bonnet internals
There are rules on cleaning and blasting profiles. One source is NACE.
With epoxy coatings only three things matter, surface prep, surface prep, and surface prep. The selection of the epoxy, its application and curing are important, but nothing will make up for poor surface prep.
= = = = = = = = = = = = = = = = = = = =
Corrosion, every where, all the time.
Manage it or it will manage you.
http://www.trent-tube.com/contact/Tech_Assist.cfm