6 replies to this topic

[Johni]

Hi All

 

If I have 300 m length pipe with a diamter of 4 in and need to estimate the required mole (mass) of propane to increase the pipe pressure from 1 atm to 50 atm , Practically, Would the ideal gas help PV=ZnRT?

 

As final pressure of 50 atm , V=Pi rseq L , R= 8.31 and T = propane temp in K

 

If no , What can practically help?

 

 

I look forward to hearing from your expereinces.

 

 

 

Thank you

[marchem]

if it is a isothermal process (at ambient temperature) you can solve directly


1) calculate density of propane at 50 atm and operating temperature

2) multiply density (Kg/M3) by internal volume of pipeline (M3) and obtain mass of propane at 50 atm

3) calculate density of propane at 1 atm and operating temperature

4) multiply density (Kg/M3) by internal volume of pipeline (M3) and obtain mass of propane at 1 atm

5) the difference Kg propane (2) - Kg propane (4) is your number

to calculate density of propane you can use graphs, tabulated values or a software
(see NIST gov, PRODE etc.)


for a different process you need to specify the type,

also in this case you can solve with charts or tables of values (mollier etc.) or a software

Edited by marchem, 24 August 2013 - 06:37 AM.

[Bobby Strain]

At 50 atm and ambient temperature, the fluid will be liquid.

 

Bobby

[marchem]

Bobby,
I hope Johni knows that C3 has critical pressure of 42.47 Bar.a

at 50 Bar you are above critical pressure for C3

density at 50 Bar.a 15 C (below critical temperature) is about 517 Kg/M3,

density at 50 Bar.a 98 C (above critical temperature) is about 329 Kg/M3,

anyway the procedure to calculate the required qty of C3 is the same

it doesn't matter if fluid is in gas or liquid state.

Edited by marchem, 24 August 2013 - 12:05 PM.

[Johni]

Thank you all for the very informative replays. I do know that. However, it just came to my mind about the applicability of ideal gas law for the real applications,

 

Once again , i'm very glad to hear from you.

[marchem]

just a comment about


PV=ZRT


for ideal gas Z = 1.0


for a real fluid Z in general will be different from 1.0


you can utilize this correlation for real fluids in gas or liquid state
(with proper values of Z)

Edited by marchem, 24 August 2013 - 12:10 PM.

[Johni]

That's absolutely true.The comprissibility factor Z can be calculated by using CNGA equation or Standing Katz chart by knwoing the reduced temperature and pressure.

 

 

Thanx alot marchem