Pipe Material for 2500# Rating

[Hessam1361]

Hello everyone,

I'm working on a gas injection project which the discharge design pressure from gas compressor is 38315 Kpa and design temperature is 170 deg C.Since it's sour we require 1.6 corrosion allowance. The discharge pipe size is 4" and it's going to an 8" header.I can't find any standard pipe wall thickness for A106 carbon steel. We could find Duplex stainless steel pipe with standard sizes for required wall thickness. Since Duplex SS is very expensive, can anyone suggest suitable material that I can find standard wall thickness without ordering customized pipe since it's just 120m length of pipe?
Thank you.

 

[Frank1344]

Hello,

If your service is sour, you are looking at minimum 3.2 mm CA and even this may increase depending on the severity of the corrosive contents in your gas composition.

What do you mean by you can't find any standard pipe wall thickness for A106 CS? With the design conditions you have, you are way above STD wall thickness probably XS, 160.

If H2S content is the only corrosion concern, I think A-106 which meets NACE requirements should do the job. again, assuming you don't have Chlorine, CO2 or any other corrosive element.

I hope this helps.

 

[Hessam1361]

Thank you Frank,

Here is my WT calculation for A106 CS.As you can see, pipe sizes more than 3" are not available in standard wall thickness. By standard I mean there is no pipe schedule available for this material at that pressure and the only way is to order customized wall thickness which will be expensive. I'm looking for some material that I can find common WT. Also we have CO2 as well.

NPS tw t c P Y E S D Schedule
2 10.44 7.53 1.6 38287 0.4 1 137895 60.3 XXS
3 14.53 11.11 1.6 38287 0.4 1 137895 88.9 XXS
4 18.16 14.28 1.6 38287 0.4 1 137895 114.3 Custom
6 25.87 21.03 1.6 38287 0.4 1 137895 168.3 Custom
8 33.12 27.38 1.6 38287 0.4 1 137895 219.1 Custom
10 40.82 34.11 1.6 38287 0.4 1 137895 273 Custom
12 48.07 40.46 1.6 38287 0.4 1 137895 323.8 Custom
14 52.61 44.43 1.6 38287 0.4 1 137895 355.6 Custom

 

[MJCronin]

As I calculate it, even Sched 160 is not thick enough for this pressure (A106-Gr b).

"Special order" piping seems to be required.

 

[GHartmann]

Not sure if they have want you want:

http://www.specialtypipe.com/products/heavy-wall-seamless.aspx

 

[SJones]

What wall thickness would you need with API 5L Grade L360 (X52)? Take it upwards to the nearest standard API wall thickness and see whether a stockist has it on the shelf.

Steve Jones
Materials & Corrosion Engineer

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

 

[syedfarhanali]

Dear Hessam1361,

Your process condition looks very critical I guess you are using this pipe for some power piping application?

I had spent some time to check, and found that API 5L Gr. X65 with the Sch. of XXS or 160 is passing on this condition,

Although I couldn't find some proper Allowable stress valve tables for API 5L, I've checked on the basis of Allowable stress value mentioned here:

http://books.google.com.pk/books?id...q="API 5L X60 allowable stress table"&f=false

You need to recheck it again.

Following is the calculation I preformed:

Pipe Size 4"
Design Pressure(PSIG): 5557 5557 5557 5557 5557
Design Temperature(F): 100 200 300 400 500
Stress Value: 46800 46800 35100 35100 35100
E 1 1 1 1 1
W 1 1 1 1 1
Y 0.4 0.4 0.4 0.4 0.4
Dia 114.3 114.3 114.3 114.3 114.3
tm 6.478262156 6.478262156 8.509076222 8.509076222 8.509076222
CA 1.6 1.6 1.6 1.6 1.6
tm+CA 8.078262156 8.078262156 10.10907622 10.10907622 10.10907622
tn 9.232299606 9.232299606 11.55322997 11.55322997 11.55322997


Pipe Size 8"
Design Pressure(PSIG): 5557 5557 5557 5557 5557
Design Temperature(F): 100 200 300 400 500
Stress Value: 46800 46800 35100 35100 35100
E 1 1 1 1 1
W 1 1 1 1 1
Y 0.4 0.4 0.4 0.4 0.4
Dia 219.08 219.08 219.08 219.08 219.08
tm 12.41695252 12.41695252 16.30943498 16.30943498 16.30943498
CA 1.6 1.6 1.6 1.6 1.6
tm+CA 14.01695252 14.01695252 17.90943498 17.90943498 17.90943498
tn 16.01937431 16.01937431 20.4679257 20.4679257 20.4679257

Farhan
Admin
EngineerPK.ORG

 

[C2it]

Farhan,

Where did you find your allowable stress values ? I assumed this piping was to ASME B31.3 ... but maybe not ?

 

[SNORGY]

As C2it suggests, when I looked, I found the allowable stresses for API 5L X65 in Table A-1 of B31.3. Fourth from last tabulated value under Carbon Steel Pipes & Tubes.

My copy of the Code (older copy, 2006) shows a double bar to the right of 400 F, though, so I don't think B31.3 allows for its use above 400 F. See Table A-1 Note 55.

 

[C2it]

My concern was (is) that since B31.3 limits stresses to 1/3 UTS or 2/3 YS, an allowable of 46800psi must equate to a UTS of 140400 psi ???

In B31.3 (2010) Appendix A, API 5L X80 has an max allowable stress of 30000 psi so I think there is an error somewhere ?

 

[syedfarhanali]

Dear Hessam1361,

One thing i came to know that this Pressure / Temperature Rating doesn't come under Class 2500,

because at the Temperature of 200 Deg C the working pressure is 366 Bar or 36500 kpa.

Also if this is not under Class 2500, the ASME Code B31.3 States that, This service of Piping will be considered as High Pressure Piping and you need to follow the rules for Chapter IX of ASME B31.3.

Also if you are refering to Chapter IX, you need to refer Table K-1 for for Allowable Stresses.

Which states that API 5L any Grade can't be used beyond 100 deg F.

Also A 333 Gr. 8, 50ksi, but can't be used beyond 250 deg F.


Farhan
Admin
EngineerPK.ORG