Compressed Natural Gas Flow Problem

[jrobinson1]

Hello gas flow gurus out there. I have a customer who wants to test engines on compressed natural gas. He has a demand flowrate of 42 scfm at 10 psig. If he intends on using 101 liter gas cylinders at 3200 psig, how long will it take for one cylinder to be exhausted at this engine flowrate? Thanks in advance for your time.

 

[BigInch]

How many engines? How many cylinders of gas?


The answer is in the attachment.

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"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[PEDARRIN2]

How about getting a natural gas compressor station.

Bauer Compressor makes these.

We placed one on a college which was focusing on eduction pertaining to alternate fuels.

 

[jrobinson1]

Thanks Biginch for the calc. I will review and get back with any questions. Thank you too PEDarrin.....looks like based on Biginch's calc, the compressor station will likely be a better choice than just storage.
Cheers,

joe

 

[zdas04]

BigInch,
I couldn't figure out your conversion factors so I put the problem into MathCAD and just let it deal with all the conversions. Got the same answer. Even when I was doing this stuff on a slide rule I would have done it with rigerous units:

t = 101 L * (m^3/1000 L) (3.2808 m/ft)^3 * (3200 psi + 15 psi)/(10 psi + 15 pai) / (42 ft^3/min) = 10.921 min

Jrobinson1,
Probably need bigger cylinders, more cylinders, or a compressor. For industrial users, the gas company will put a "high pressure" meter and supply you with 10 psig gas without doing any of this.

David

 

[BigInch]

I used Windows Calculator; no units capability, so I just wrote down the conversion factors from my own head. As long as you got minutes, you're good.

I figured he's doing something that needs mobility and only small cylinders fit onboard = no compressor station, no utility connection.



**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[zdas04]

I guess absent any new information we can assume any damn thing we want.

David

 

[BigInch]

Works for me.
Hope the Turkey is defrosted by now. Happy Thx_d!

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[jrobinson1]

Thanks Zdas04....I like your idea about the high pressure regulator from the gas company. The engines will be tested on stands in an engine test cell facility, and the rate given is the expected largest engine that they will be testing. The 10 minutes is not going to be practical due to endurance testing around the clock. I think they are on a shoe string budget too, so a bulk storage or compressor is not going to be received too well. I will look into the gas company option....thanks so much for both of your confirming calcs.
Happy Turkey Day!

joe