Properties and State of Methane 1

[wallace24]

Here's a situation that has me confused.
For Methane, I have a P vs T chart that shows a critical temperature of -166F, Pcrit = 668 psia.
Now - for room temperature, which is well above -166F, would methane be at a higher temp using the PV=ZmRT?
In reality, methane is pumped into pressure vessels and very hard to liquify - so at low pressures (several hundred psi) it just depends on how much the pump pressure is.

What am I missing here? Any help would be most appreciated.
Thanks.

 

[JStephen]

I don't really see what it is you're asking.

 

[Montemayor]

You've got me banging my head against the wahl, trying to understand what it can be that concerns you.

If you are a mechanical engineer, you must be well-versed in Thermodynamics and, therefore, aware of what a superheated gas is - which is what Methane is when it finds itself below its critical pressure and above its saturated temperature. If you look at the T-S diagram for Methane (like for example that in the GPSA Engineering DataBook) it is that area to the upper right of the saturated dome-like curve shown on the T-S diagram.

If you don't understand the above, then what you are missing is several well-immersed courses in Thermodynamics. We can supply you with several names of some good sources of information if you let us know.

 

[Zoobie]

Your question:
Now - for room temperature, which is well above -166F, would methane be at a higher temp using the PV=ZmRT?
The answer:
Yes! At room temperature methane will be at a higher temperature for all rooms that are warmer than -166F.

Sorry for the sarcasm, but it appears from the previous two posts that you have not phrased your query that can be readily understood...at least for english speakers...oops there goes the sarcasm again. I should really get that looked at.

Anways, from what we can understand about your concern there are several people here that can help with specifics about the properties and state of methane. Perhaps you can try again.

 

[wallace24]

I appreciate your comments.
Double checking my post in the future would be a good thing.
The sentence -
"Now - for room temperature, which is well above -166F, would methane be at a higher temp using the PV=ZmRT?"
The word "temp" near the end of that sentence should be "pressure".

Thanks for your replies and time to teach me a lesson to get my ducks in a row just a little bit better (for English speaking people - that is.)

 

[Latexman]

wahlbanger,

Yes, a pressure vessel with a fixed quantity of methane in it will be at a higher pressure at room temperature versus a temperature of -166 F.

Good luck,
Latexman

 

[25362]

To wahlbanger,

Probably not relevant, but the critical temperature of methane is -116^oF, not as given. Am I right ?

 

[wallace24]

Dear 25362,
Yes, it's -116F.
Thanks, WahlBanger