Rate of Expansion & Contraction of CO2

[ryanonthebeach]

Hi All

I have what I thought was a simple question but can't seem to figure out the answer.
If I have two fixed volume chambers with large surface areas (for simplicity, let's assume perfectly insulated and temperature controlled), one at ambient temperature say 30c (C) and the other (H) constantly heated at 90c. A pressured CO2 liquid (1000 psi in C) is pumped from C to H at rate of X, left until pressure reaches max (time Y), then pumped back at rate X.

How do I calculate how quickly the pressure in the H will come up (Y) and down for C to determine what X should be, and will there be any losses due to speed of temperature change of the substance? i.e. the rate at which it is introduced to H or C.

 

[vpl]

Is this for homework?

Patricia Lougheed

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[MortenA]

Your problem contradicts itself:

If its perfectly insulated and temperature controlled - then pressure will be reached instantaneously! Why: Because the rate depends on "heat transfer" that is suppplying enough heat to evaporate sufficient CO2 so that the pressure where CO2 has a boiling temp of 90ºC is reached. I have previously posted a reference for a very fine CO2 phase map.

So that unless you have a heater whit a know duty and a know mass of CO2 then theres no answer. If you have its quite easy given your assumptions and the chart.

Best regards

Morten