Vessel Material Selection fro Hydrocarbon Service

[Ulon]

Hi all,

I would like to ask, why some vessel is lined and some is unlined?

Usually we are using 316SS as the material or DUPLEX. Any body got comparison of these two? and what makes them to use exotic material like Hastelloy C?

Thanks in advance

 

[gr2vessels]

The corrosion resistance of materials varies a lot, some expensive and "exotic" materials have a high resistance and strength in certain application, others like Carbon Steel are vulnerable in corrosive environment, hence an internal lining could protect the the equipment from the harsh process fluid.
However, for each application and each piece of equipment, or group equipment, an experienced materials engineer makes an assessment of the suitability of various materials and select for approval a number of them. On the basis of that assessment, the Client / project management would select the most feasible material, including the lining material as required.
I also found your statement of using stainless steel on the habitual basis, rather then application, quite interesting. Do you make air receivers of Duplex stainless steel?
cheers,
gr2vessels

 

[MJCronin]

Unlon..

Your question is very general and difficult to answer in this knid of forum..

Can you be more specific ?

-MJC

 

[Ashereng]

Typically, liners are used to deal with corrosion, and more generally, material incompatibility between the fluid and vessel wall.

316SS, duplex, hastelloy, etc. are materials. These are used, again, to deal with fluid to vessel wall material compatibility (eg. corrosion).

I say compatibility, and give corrosion as an example. Another examples may be reactions - the fluid may react with the vessal wall material to give a undesireable intermediate or product.

In the end, it all comes down to chemistry, and cost - mostly cost. Is the cost of exotic metal more economical than liner? Or, is a less ideal material more economical than the ideal material? How long does the tank have to last? What are the consequences of one material/liner than another/nothing?

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?