100 psi+ Natural Gas Piping Guidelines

[dbarker72]

I am looking for some guidance on designing a natural gas piping system that connects to a natural gas compressor with a 95 psig suction and 240 psig discharge. I am a PE who normally deals with 5 psi and under systems and want to get more than my pipe sizing correct. Seismic concerns, etc.

Anyone have any good resources and/or advice?

Thanks.



dbarker72

 

[BigInch]

A few more details will get you moving in the right direction a whole lot faster. What's the project and design code? Gathering sys, transmission, dist or fuel gas, process gas, temperatures, expected line size?

For now go to pipingdesign.com. Not a bad place to start.

Going the Big Inch!

http://virtualpipeline.spaces.msn.com

 

[dbarker72]

More Info:

All piping will be inside a "power house" building to serve a gas turbine connected to a boiler serving an entire campus system. This is to replace/parallel an older outdoor compressor unit. Suction side run will be no more than 200' and discharge no more than 50'.

Tying into existing 10" line and client provided 95 psig as suction pressure. 4" suction attachment to compressor.
Temps: 90 deg F going in, approx 180 deg F coming out.
Discharge: 3" line to deliver 2.375 MMscfd @ 240 psig
So, I get 2.667 MMscfd supply using the gas laws.


dbarker72

 

[Zapster]

mmscfd (million standard cubic feet per day)
Not sure how this can change from what is going into the compressor and what is coming out. What is the actual flow in mmscfd? Also, it would be helpful if you stated what the STD conditions your are referencing.

Anyone have any good resources and/or advice?
Hire a consultant or find a good mentor in your office who is familiar with the relevant code (B31.3 if applicable in your jurisdiction).

 

[BigInch]

Right, not a trivial solution. OK, so I'll give you some more things to think about. Hope you have a lot of "learning curve" planned for this job.

Balance the gas supply with discharge, unless the difference is due to the compressor fuel consumption.

This is probably a Class I, Div. II installation. Explosion "proof". Find out where the existing ignition sources are. Need gas detectors?

Local code provisions may apply, at least to the fuel gas supply for this compressor.

180 seems high for fuel gas supply. Don't know so maybe you should check turbine's fuel temp allowable. Personal protection insulation is required on discharge.

You will need block valves in the suction and discharge lines and for the fuel gas supply to this compressor.

Will any regulators be needed for fuel gas supply to this compressor?

Any flow control for the compressor needed?
Any discharge control valve needed? I guess probably not.
Will compressor have a remote control panel or only local?

A local ESD on the compressor is probably required, with blowdowns to outside of suction and discharge lines. Tie the ESD into the turbine's ESD too.

Air change requirements and additional heat load may affect the HVAC.

"Flexibile restraint" is the key to good pipe stress design.

Fire suppression load increases. Any modificatins required?

OK, Probably enough to keep you busy for a couple of weeks.

Going the Big Inch!

http://virtualpipeline.spaces.msn.com