9 replies to this topic

[farid.k]

Hye.
Sorry for the simple question. Any reference for the material selection? I.e. For sulphuric acid,carbon steel or carbon steel with ptfe lining. Can I have a complete reference? I have a complete list but some of the chemicals not in the list such as corrosion inhibitor.. So I have no basis for the material selection.

[curious_cat]

What concentration of acid? 

[farid.k]

What concentration of acid?

Acid 98%. When I referred to material selection, it specify carbon steel.

For corrosion inhibitor I don't know what type of chemical they use..thus I don't know what type of material I can choose.

[Zauberberg]

For corrosion inhibitor you don't need to worry, it will be Carbon Steel. Otherwise if the inhibitor would require CRA, what is the point of injecting such chemical?

 

98% H₂SO₄ is well handled by Carbon Steel at ambient temperatures (up to 38 degC). Another thing is piping velocity limitation: generally recommended for CS is not to exceed 1 m/sec, with SS you can go up to 2.5 m/sec.

 

There is quite a few topics on Sulfuric Acid at ChE. Try the famous "search" function.

[farid.k]

For corrosion inhibitor you don't need to worry, it will be Carbon Steel. Otherwise if the inhibitor would require CRA, what is the point of injecting such chemical?

98% H₂SO₄ is well handled by Carbon Steel at ambient temperatures (up to 38 degC). Another thing is piping velocity limitation: generally recommended for CS is not to exceed 1 m/sec, with SS you can go up to 2.5 m/sec.

There is quite a few topics on Sulfuric Acid at ChE. Try the famous "search" function.

Your answer never disappointed me.
Thanks so much for the info.
Just that, I need a list of services and suitable material for that.I.e for fire water..what material.. For chlorine gas what material..do you have any good reference? or it will be in the company standard for piping?

[Zauberberg]

That's a rough task and would require oversight from the Materials and Corrosion engineer. There are so many chemicals and fluids in the industry that no one so far (up to my knowledge) has developed such a comprehensive guide. Then add pressure and temperature variations, presence of corrosive compounds, water, etc. etc. Too many factors.

 

Try to obtain a copy of the following reference books - they do provide some interesting guidelines:

 

R. White, "Materials Selection for Petroleum Refineries and Gathering Facilities"

M. Kutz, "Handbook of Materials Selection"

N. Cheremisinoff, "Materials Selection Deskbook" (here you can find some general guidelines - I have attached a material table in this post)

Attached Files

•  Pages from Materials Selection Deskbook.zip   121.92KB   72 downloads

[farid.k]

That's a rough task and would require oversight from the Materials and Corrosion engineer. There are so many chemicals and fluids in the industry that no one so far (up to my knowledge) has developed such a comprehensive guide. Then add pressure and temperature variations, presence of corrosive compounds, water, etc. etc. Too many factors.

Try to obtain a copy of the following reference books - they do provide some interesting guidelines:

R. White, "Materials Selection for Petroleum Refineries and Gathering Facilities"
M. Kutz, "Handbook of Materials Selection"
N. Cheremisinoff, "Materials Selection Deskbook" (here you can find some general guidelines - I have attached a material table in this post)

Thanks for the sharing..I've been working with shell and they have a list for that. Say, for fire water, what kind of material..For offshore like crude oil, sour or not sour what is the proposed material..lining.. , it has a list for material selection. Same goes to onshore..nevermind..thanks so much for the sharing..

[curious_cat]

+1 to what Dejan wrote. 

 

MOC selection is one of the most complex topics out there and no good formulaic way exits. 

 

In addition to the factors Dejan mentioned the exact alloy composition often matters. Things such as heat treatment, stress profile, crevice creation by bad design etc. can matter. 

 

Also bulk compositions are not even half the story. Often the governing corrosion chemical is something present in  ppm quantities. The bulk might be corrosion safe but this impurity will cause you severe corrosion. e.g. Chlorides for stainless, flurides for glass linings etc. I've seen the opposite example reported too e.g. chlorides are normally very corrossive to stainless but in the tanning industry some of the co-present impurities generate some beneficial protective action against chlorides. 

 

Another important parameter is the aeration levels. Those can matter a lot. 

 

One reference I like is "Handbook of Corrosion Data  edited by Bruce D. Craig, David S. Anderson". It has actual industrial & lab data on corrossion rates in various environments. 

 

I'm still amazed how the same material in slightly different settings can yield such different corrosion rates. Sadly, sometimes apparantly the same T / P conc. conditions at two different sites give such different data that one is foxed. Just goes to show how inexact a science corrossion quantification has remained. 

 

 

https://books.google...on data&f=false

Edited by curious_cat, 17 April 2015 - 10:45 AM.

[Zauberberg]

Richard White's book contains Appendix (A) with guidelines for material selection based on the fluid and service conditions. Fluids are those "most common" in the Hydrocarbon industry.

[breizh]

hi farid ,
You may find some tips in the attached documents . Definitely a corrosion expert could help you.
Good luck,

http://www.tantaline...rrosion-57.aspx

 

http://www.ssina.com...ons/design.html

 

Breizh

Edited by breizh, 18 April 2015 - 03:16 AM.