Piping and Valve Materials

[rpedde01]

Hi,

i am designing fuel control skids for the Diesel, Natural Gas, Heavy Fuel Oil and some of waste fuel oils.

The pressure and temperature ratings are

Diesel 150psi, 30°C.

Gas 70psi, 30°C

Heavy Fuel Oil 150psi, 200°C.

I need some assistance in decided the right material in each stage of the skids.

i would say the important components for the skids are

1) Manual ball valves
2) Strainers
3) Pressure Regulators
4) Control Valves
5) Pipes
6) Check Valves
7) Pressure Gages

i would like to know what kind of materials i can use, Brass, Stainless steel, cast iron, carbon steel.

i would also like to know ,

when should we use threaded VS flanged?

when should we use welded VS threaded?

please help.

Thanks in advance.

 

[jber82]

I would think most of this would be covered in a company spec, if not I would recommend hiring a firm that has specs for this. Below is what I would use, since I don't know your whole scope I made it pretty general

Carbon Steel with 150# flanges should be fine for your temps and pressure. Fuel oil is getting close to the limit of the flanges but still under. You might need to check stresses on these sections. I wouldn't use anything that is threaded.

What type of welds you put on your fittings and branches would depend on the size. Fittings anything under 1-1/2" should SW, above should BE.

Valves probably need to have 13% CR trim.

http://engineerhumor.com/

 

[JLSeagull]

Your materials depends upon the client standards, industry standards, legal jurisdiction, insurance requirements etc. Also, the year that projects are executed can affect which standards apply. Often contracts dictate some of these standards. Perhaps you must comply with ASME B31.3 for the piping systems, B16.34 for valves, B16.5 for flanges, etc. Both ASME B16.34 and B16.5 were revised in 2009. However if a project was awarded before either standard was revised you could establish the previous revision as the project design basis.

Clarify if these are normal or maximum conditions - and the setting for the process safety relief valves etc. If carbon steel, the fuel oil at 150 psig, 200°C would appear to be in the Class 300 piping system and other fluids appear suitable for Class 150 flanges. You need to check the standards that apply.

You need access to the project standards and the basis for the project design for your area and industry.