Erosion/sliding abrasion/corrosion resistance material

[GURU2020]

Hello everyone,
Problem : Frequent failure of 8" SS304L pipe line due to the slurry erosion.The pipeline faces a vertical ( top to bottom) flow and the isometrics of the pipe has two elbows 30 and 45 degree. The erosion mainly takes place the hitting edges of these elbow outlet regions.
Process media : petcoke slurry; temperature will be around 70-80 degree Celsius ; it contains chlorides and little H2S. velocity may be around 15- 20 m/s

The erosion mainly takes place in the extra-dose of the elbow and bottom side of the slant pipe line ( sliding abrasion)

Immediate action taken : conforma clad. this gave as temporary relief of about 6-7 months breathing time.

i am here looking for extended life of these lines. I have searched and found few possible solutions as enlisted below,

1. High manganese Steel- Better impact resistance and work hardens. But it lacks sliding abrasion resistance
2. UHMWPE pipes - Heard these have good properties to meet my requirement. But does this handle pressure ? Any experience comments and thoughts required please
3. Basalt lining - Good sliding abrasion ; but Impact resistance ???

i would like to hear more about solution of my problem

thanks in advance.

 

[arunmrao]

I have limited knowledge of Basalt linings. However, in one of the studies for a coke oven used in steel plants, the original lining was Manganese steels, but due to poor wear properties needed to be replaced in 3-4 months time.

A comparative study was done using high chrome iron casting( manufactured by us)and Basalt lining.

High chrome iron extended life over Manganese steel by 2-2.5 times. While Basalt linings proved to be the best. However, the cost of the Basalt lining was very high.

Hope it helps.

 

[EdStainless]

the Mn steel would not like the corrosion, and it doesn't work harden much more that SS does.
Have you though of using 201LN, Nitronic 40, or 2205? These are all much stronger than 304L.
These alloys also work harden a lot (esp Nit40) so you could shot peen the surface to improve wear resistance.
Hard facing with HVOF or similar fusion method that limits substrate heating (not weld overlay) is also an option. There are many mixed carbide systems out there. Talk to a surface treatment guy.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[0707]

Is it possible to use a ceramic linning like "produr durzalt"?

luis

 

[GURU2020]

EdStainless:

Thanks for the reply.

I have looked upon the SS2205, it have indeed better hardness property.But it has lack of abrasion resistance property.
Nitronic - Is it possible for making pipe section using Nitronic ?
HVOF - it is good idea with TC coating. But HVOF is limited to maximum of 3 mm. This again will not give extended life. I taked with vendors they suggested for Stellite 06 overlay inside the pipe using MIG

 

[EdStainless]

Go back and read the old papers from DOE on coal slurry erosion. If the surface doesn't wear then thickness doesn't matter. The problem with pipe systems is that erosion changes with impingement angles. And balancing corrosion makes it harder.
There are people out there making pipe in Nitronic alloys.
There are also a number of diffusion treatments that could be used, but then fabrication gets very difficult.


= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[IFRs]

would using long radius elbows help? Like 10D or more?

 

[IFRs]

Would increasing the diameter as the elbow goes around the corner, or at the end of the elbows help?

 

[Dhurjati Sen]

Apart from material upgradation, flow control (velocity below 6 m/s) and wash water injection options could be explored.

Material upgradation should be the final option.

DHURJATI SEN
Kolkata, India

 

[kingnero]

I believe process adaptation would be more difficult than selecting a (more) suitable material (or even modificationn of existing materials using cladding/overlay or HVOF treatment).

 

[GURU2020]

Just an update . I am exploring more on PVDF lining/coating. which studies claims to be of more abrasion restiveness. I am talk with few vendors as well.

If any one could throw some light on this PVDF on slurry abrasion. It will be helpful.

Thank you all for your valuable inputs. I ll look into those aspects as well.

 

[EdStainless]

Because these PVD coatings are very thin it is important that the substrate is strong enough to support it and prevent cracking of the thin brittle coating.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[btrueblood]

Uh...PVD or PVDF? PVD = plasma vapor deposition, usualy a ceramic or cermet. PVDF = poly vinylidene di-fluoride, a polymer somewhat similar to teflon.

 

[GURU2020]

Not PVD.

its PVDF Polyvinylidene fluoride. It is commonly known as Kynar.

I have attached document upon this PVDF for a reference. @Edstainless steel.

 

[EdStainless]

Sorry, read too fast.
So how are they guaranteeing adhesion? If this dis-bonds at any point the entire coating fails.
And how will you be joining pieces in the field without damaging the coating?

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[Agent666]

I know nothing of the coatings etc being discussed, but reading the original issue it is stated the erosion occurs at the elbows though which no one seems to have discussed.

Would a change to the pipe geometry help here, like a sweeping larger radius curved portion of pipe be something to look at rather than two shaper elbows (though obviously don't have in mind what geometry is now as not provided having scanned through the thread)? Combined with some coating it may last longer between replacement being required. Make it in a way that is easily replaceable if it is considered a throwaway item after a specific time period, bolt in and bolt out with new section on some regular basis.

It seem to me you're trying to solve an issue without maybe thinking bigger picture in terms of minimising the issue in the first place. Obviously there are probably constraints, etc, but throwing it out there in case it's not been considered.

 

[0707]

GURU2020

Have spare pipe flanged ceramic linned elbows 30 and 45 degree. Periodicaly when a leak occurs in your unit you will have a spare part to replace your elbow section. Is it your unit a FCC unit?

regards

luis

 

[KvdW]

Just to provoke the thought process - maybe not directly applicable to this issue:

Google "gamma bend elbow". These elbows are used in pneumatic conveying of abrasive solids. The concept is that the accumulation of product in the outer curve of the elbow absorbs a portion of the impact of changing direction, instead that the pipe wall takes all the impact and abrasion. I don't know to which extend this behavior can be translated from solid/air mixture in pneumatic transport to a solid/liquid slurry.

The googled images will show you some off-the-shelf products. I couldn't find the version that I've been working with previously, which just had a thick steel plate, curved only in one direction, on the outer curve. These were flanged elbows (45° and 90°) converting from (to) round pipe to (from) rectangular cross section (perpendicular to flow direction). And having a long radius to facilitate the pneumatic transport.

 

[GURU2020]

@Agent666

Thanks for the input. Erosion happens in elbow and slanted pipe portion below. Please read the problem statement. This service is totally highly abrasive slurry contains pet coke, ash, water. The solids are in 4-10 wt% solids. which is the main cause of erosion.

Initially with SS304 , the pipe line was giving up in 1-2 weeks. Now we have lined the pipe with conforma cladding.This gave us a breathing time of 6-8 months.

i am here looking for more.

@0707
It is Gasification plant. Syngas production.

@kvdW

Thanks for the input. I will look upon it.

 

[saplanti]

Have you tried Ni-hard IV or NiResist as the elbow material. They might be helping you. The other option might be the ceramic coating as mentioned earlier. One might be better than another. Or you can use the combination. The environment is difficult, all the options have short but better lifetime.