1 reply to this topic

[Matteo Giorgio Marrano]

Goodmoring guys,
i'm currently working for a hydrocyclone package consisting in some equipments like oil skimmer, hydrocyclone and nutshell filters for the treatment of oily water coming from desalters, separators etc..

The oily water cointains
- 200000 ppm of salt
- 1780 ppm2 H2S
- the system is workin at the following pressure from upstream to downstream:
oil skimmer: atmospheric
hydrocyclone: 8 barg
Nutshell filters: 5 barg
Treated water out: 3 barg
- Temperature: max 60°C

All vessels are in carbon steel with internal lining of 375 micron in order to protect from salt.
Our client asked us to construct the vessels with NACE plates due to the presence of H2S.

I would like to know if this is necessary or not, considering that the CS is protected with the internal lining. I've purchased NACE M0175 but im' studying it..I think that the use of NACE plates,if not necessary, would increase fabrication price..

regards and thanks
MAtteo

[kkala]

i'm currently working for a hydrocyclone package consisting in some equipments like oil skimmer, hydrocyclone and nutshell filters for the treatment of oily water coming from desalters, separators etc..
The oily water cointains - 200000 ppm of salt - 1780 ppm2 H2S
- the system is working at the following pressure from upstream to downstream:
oil skimmer: atmospheric hydrocyclone: 8 barg Nutshell filters: 5 barg Treated water out: 3 barg
- Temperature: max 60°C
All vessels are in carbon steel with internal lining of 375 micron in order to protect from salt.
Our client asked us to construct the vessels with NACE plates due to the presence of H2S.
I would like to know if this is necessary or not, considering that the CS is protected with the internal lining. I've purchased NACE M0175 but im' studying it..I think that the use of NACE plates,if not necessary, would increase fabrication price.

You have not advise pH of water, assumed below 6 for this case.
Since weldings should be annealed, NACE would result in serious increase in fabrication cost (it is said to be doubled for piping).
It is not easy to foretell whether internal lining would effectively resist abrasion in hydrocyclones. Some of these linings show excellent durability, yet this is a matter of experience and experimentation. Sometimes lining is destroyed locally and water goes beneath it.
Everything depends on experience gained from previous cases. I would not apply NACE standards in fabrication only in case I were certain about the durability of lining.