Internal Coating of Pipes for Alcohols, Solvents ... 1

[jeypeevee]

Hi. Can anyone guide me if there's a standard to know if I should do internal coating for my pipes, if the products that will flow for each pipes are alcohol, solvents and fuels? What type of internal coat should I used? Is it the same to inorganic zinc we used in our internal coating of our tanks?

 

[LittleInch]

Why do you want to / need to internally coat?

Normally you do this for either corrosive material or friction reduction. How you coat at welds / joints is always difficult.

What pipe material / size are we talking here?
Why do you internally coat the tank?

Lining can be an alternative but what types of "solvents"

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[jeypeevee]

Hi LittleInch. We'll be using our old stock of pipes which are carbon steel material. It was suggested to me that I should do internal coating to prevent corrosion but someone also said that if the product is just alcohol, no need to do internal coating unless the product its petroleum oil. That's why I want to know what's the basis or standard for this.

Ethyl acetate is the solvent that we will store.

 

[bimr]

You need to provide more information on the process application, such as temperature, pressure, climate, etc. Is there any concern of product contamination from the piping corrosion products?

 

[LittleInch]

"Old stock of pipes" isn't a great start.

I would suggest you include some internal cleaning and maybe an internal sweep blast to remove and corrosion products which "may" react with you liquids.

However I don't believe any of those substances will cause corrosion to Carbon steel.

There are millions of kilometres of carbon steel pipelines and pipes containing "petroleum oils" around the world which are not internally coated so you will be in a small minority.

Coating is not normally possible at the welds and hence internal coating is not normally regarded as being a good method of protecting pipes from corrosion.

I think whoever suggested this to you may have heard of it once somewhere that a friend told him about. Question whoever told you this to explain further and when no answer appears, just forget about it.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[1503-44]

Ethyl acetate has excelent compatibility with carbon steel. Plastics and other materials, especially used for sealing inside valves and other components usually present more of a problem then the pipe. You should not use polypropylene or any other "D" or "-" material as pipe or within any of the system's components, valves, gaskets, instruments, etc. No need to guess. Simply check the chemical compatibility charts. This is from page 18 of Grayco's chart linked below.

Grayco Chemical Compatibility Chart (PDF format)


“What I told you was true ... from a certain point of view.” - Obi-Wan Kenobi, "Return of the Jedi"

 

[SJones]

USACE / NAVFAC / AFCEC / NASA UFGS 33 52 80

DIVISION 33 - UTILITIES
SECTION 33 52 80
LIQUID FUELS PIPELINE COATING SYSTEMS

Jet engines like their fuel clean. As to the other chemicals mentioned, it is probably cleanliness that will govern any need for coating, but I'm not aware any regulatory requirement. Selecting a coating will require a qualification exercise with the coating manufacturer with particular emphasis on chemical resistance.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

 

[1503-44]

No regulations apply, however purchaser's specifications of aviation products usually will. Is this an aviation product?

“What I told you was true ... from a certain point of view.” - Obi-Wan Kenobi, "Return of the Jedi"