CO2 Pipe Sizing

[232gulfstream]

Can anyone tell me where I could find information on CO2 pipe sizing? More specifically gaseous CO2? I have a dry ice production facility that is fed liquid CO2 to the ice production. I was able to calculate the GPM of this based on the mass flow rate requirement on the machines and the density of the CO2 at that phase and use the piping manufacturers charts. For the return (revert) CO2 to the recovery pumps I am told this can just be basic copper piping but how is it sized? Since I know what the connection size is on the machines for the gaseous CO2 piping I just made sure I had equal or greater free area of the piping main back to the recovery pumps. The cfm is 226 and 452 respectively. Thanks.

 

[HVAC-Novice]

You could try EES. it sure has CO2 data and can do pipe pressure loss. For fittings you could do equivalent length.
EES (or other sources) also can give you the thermodynamic properties of CO2 at that pressure/temperature and you could create a fluid in Revit. but it may be a bit shaky with accuracy since that never was built for fluids outside normal HVAC use (water and glycol).

 

[nuuvox000]

I know for refrigerant that the gas line is always bigger than the liquid line but I'm not familiar with CO2. If all else fails, I bet you can use the Darcy-Weisbach equation and figure out the head loss; then you could size it that way. You might also just make a call to the manufacturer of the machines and they most likely have some guidelines you can use.

 

[chicopee]

Your success will depend on your knowledge of thermodynamics. For references Perry Chemical Engineering and Kent "Power" handbooks have an abundance of information on CO2 however to understand the information, knowledge of thermodynamics is essential. Even if you can procure handouts from CO2 distributors that allows you to calculate pipe sizes and their related fittings, knowledge of thermo is still essential. Another source of reference is the periodical Chemical Engineering and that will require some initial research on the internet. CO2 has seen a resurgence in its use for the last decades as it was use as a refrigerant in years past so you may also contact manufacturers of CO2 refrigerant equipment for technical brochures. Research is the name of the game in your case.

 

[Snickster]

What is operating pressure and temperature of this line. Is the flow you show in SCFM? Is this line a return line to an existing compressor? Basically you just need to do a flow calculation using a typical gas flow equation and limit velocity to 60 feet per second based on generation of noise. With velocities below 60 ft/sec the pressure drop will be low enough also for your application.