Erosion of desanding liners 1

[sanshu1111]

Dear all,

We are facing severe erosion problems on desnding liners installed on produced water system. These desanding liners are of DSS (UNS 31803)and a part of multicyclone desanding vessel.

We can understand some erosion on the liners due to sand but the rate at which erosion is taking place is a bit of surprise. Please find attached results of boroscopy on damaged liners which were found within 6 weeks after installation.

Please advise if anyone has faced similar problem? Any recommendation to resolve the problem? Desanding system is operating at appx 25-30 barg @ ambient temperature.

Regards

Sanj

 

[gr2vessels]

I doubt it that is only the erosion the culprit;- the corrosion is also a major factor. I imagine the produced water contains 10,000-20,000 ppm cholrides and the 'ambient temperature' is about 40-50 deg C, over 30 deg C anyway. I would consult the NACE MR 0175 over the suitability of those duplex liners on your process. Also, what is the flow velocity over the liners.
The point is that the surface of the liner is affected by both corrosion and erosion. Can you provide some details of the produced water composition, velocity in the liners, temperature, etc?

 

[EdStainless]

What drove the original alloy selection?
Why didn't you select a more corrosion and/or erosion resistant alloy?
In this service I have used either High Cr white cast iron, Ni-Hard, or a cobalt based alloy.


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Plymouth Tube

 

[sanshu1111]

Salinity of the produced water is below 6000 ppm but to my understanding, DSS is quite resistant to corrosion in high chloride service at a relatively higher temperature application also?

This is not a case of corrosion since we have not found any signs of corrosion or erosion in the piping and the vessel. Erosion is only reported in the liners which are inside the vessel. Liners will no doubt experience higher velocity compare to velocity in the piping due to vortex formation in the liner conical section and gravity separation of the sand.

UNS 31803 was considered for the piping and desanding vessels mainly due to better erosion resistance in sand service. Liners were propritary design with only two material choices (DSS and Ceramic)available from the vendor. Ceramic is fragile and require special handling and therefore preferance was given for DSS.

Regards

Sanj

 

[gr2vessels]

OK, seems you are stuck with one supplier who can only provide DSS liners. Also, you have not much control over the process and the selection of liners. So, without changing something in this scenario, how do you expect a miracle change to occur? It is obvious the design of the equipment is not suitable for your separation process and something has to change. BTW, you did not provide the fluid composition, ph, CO2, etc. which could contribute to increased metal loss. Do you have the analysis?

 

[sanshu1111]

Dear gr2vessels
This was not based on a single vendor, most of the vendors came back with the choice of only DSS or ceramic for the liners. I also hope that DSS is not first time utilized for the desanding liners. Can you please share your experience on MOC other than DSS or ceramic for the liner material and suppliers.

Do not have data handy with me on pH and CO2 but we have entire system (connected piping, desanding vessel etc) in DSS and do not have any signs of corrosion. There are however some damage on inline instruments which is possibily due to sand erosion.

 

[gr2vessels]

You can evaluate yourself, free download DNV RP 0501, Erosive Wear in Piping Systems 2007. You can also consult the Outocumpu 'CORROSION HANDBOOK' and many articles on internet regarding the critical fluid velocities for Duplex Stainless Steel in corrosive/erosive service. You might even opt to observe the reply to your post from EdStainless. Finally, you might want to consider consulting a materials engineer in your vicinity for specific advice.
Cheers,
gr2cessels

 

[SJones]

The arrangement of the unit is an erosional classic and DSS is not exceptionally erosion resistant. If the process cannot be changed, then the only option is to change the exposed material either by overlay/coating, or completely. People are getting smart with chemical vapour deposition of tungsten carbide which might lend itself well to the item in question

http://www.hardide.com/

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

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

 

[EdStainless]

There does not need to be obvious signs of corrosion for it to be a significant component of what is happening here.
DSS is used in this service. Suitability largely depends on a combination of corrosion and sand morphology.
Your only real option is to go to the ceramic liners or engineer a replacement yourself.

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Plymouth Tube

 

[sanshu1111]

Thanks for your replies. We are trying to find out if ceramic liners are available with the required size to replace existing DSS liners. Will also try to find out if chemical vapour deposition of tungsten carbide is possible for the DSS liners which are narrow with appx inside diameter of 10 mm at tail end.

Thanks again for yoru replies.

Regards

Sanj

 

[LittleInch]

It would be interesting to know for the future what was specified to the vendors in terms of sand quantities and also what type of "sand" it is, i.e. hardness, was it rounded or angular grains, did it contain any other particles, e.g. fracturing particles.

Then try and find out exactly what the actual density and type of sand was that went through it.

Vendors can only work with what they are given and if you have particularly hard "sand" then things won't work out as planned.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[jheijneman]

Within the Bodycote S3P Group we have treated similar liner out of DSS very succesfully with the technology Kolsterising. Depending of the fraction of sand particles, the wear resistance and thus the life time can increase significantly!
The surface hardness can achieve ranges up to 1200 HV0,05.
The hardness can be achieved very uniform upon the components geometry, so also in the bores of these liners. Galling issues can be avoided as well during assembly.
Please contact me case you need any additonal information!

Best regards,

Jeroen

Contact Info:
nl.linkedin.com/pub/jeroen-heijneman/14/a8/842