Natural gas industrial pipe sizing... what method is industry standard

[USAeng]

What do people do in the industry these days to size pipe length and diameter and also calculate flowrates based on the btu of the gas and btu demand of the unit. This is going in power plants that ignite the gas to then ignite the main coal fuel. I would know the megawatt demand of the igniter then I find the btu and cfm from that... but then what? Are they using equations and paper or is it all done in computer programs? or? I am trying to get into this and find equations like the Peng-Robinson Eqn and the Bennedict-Webb-Rubin-Starling eqn and dont know if people still use these equations? I am just hoping for a good starting point to begin practice. Thanks.

 

[DLite30]

The Weymouth equation is a pretty standard calculation method used. Plenty of information on the interwebz.

BWR is mainly used for gas compression head/efficiency calculations.

 

[zdas04]

What kind of pressures are you expecting at the plant gate? If you are seeing pressures greater than about 2 atm(a) (call it 13 psig in most of the USA outside of the mountainous or seaside places), then the flow can be considered incompressible and any of the empirical equations can be used (Weymouth, AGA Fully Turbulent, or Panhandle are the ones I see most often, I normally use AGA). It is not usually necessary to go back to an EOS for incompressible flow problems.

If your pressure is much lower than 2 atm(a) then you can get some really flaky results from the incompressible-flow equations and I generally go to the HVAC folks for their low pressure equations. Compressible flow is really difficult to evaluate and the HVAC industry has done an excellent job of developing correlations that work at the pressures they normally work at.

David

 

[USAeng]

Thank you... I have heard of some of these equations and remember using them back in college once in a while... What about Chen and Shacham equations? Do you guys see these equations being solved freehand for large systems, or are people using excel or other computer software and just clicking on which equation they want to use and inputing a few variables? If the industry is using software to solve these problems what is a good program?

Also I see some of the equations are for horizontal pipes or have a factor for small angles that can be used.... but what about large angles and vertical runs? I solved small simple piping problems in college, but these are going to be more involved.

I just want to know where to start or maybe a really informative paper or book that I can learn how to use these equations... If I cant find a good reference I will prob. go back to the university and ask some of my old professors for guidance... nobody to help me here at my company unfortunately... thanks for all the help so far
Thanks.

 

[dcasto]

your question is why we have consultants and professionals that can answer your question.

 

[USAeng]

yeah... maybe at some point when we begin this work my company will consider hiring a consultant to help with the first job or two... but this is purely for my information for now... I want to begin learning more about this topic and was simply asking for good resources

right now hiring a consultant would make no sense for various reasons one being we are not getting any of these projects in the near future

 

[BigInch]

DO NOT use Weymouth for industrial plant piping. It is based on 24-30" diameter longer transmission pipeline studies and is not suitable for small diameter relatively short in-plant lines.