Auto refrigeration of Ethylene
Auto refrigeration of Ethylene
(OP)
Dear All,
I've got Ethylene gas at 15 deg C and 12 Kg/cm2(g) pressure and I'm letting it down to 1.5 Kg/cm2 (g). I'm trying to calculate the auto refrigeration of Ethylene at 1.5 kg/cm2 which I got from Hysys as -76 deg C. I think this temperatue is quite low. I've checked the P-H diagram and it indicates a much higher temperature.
Can you please give me a idea whether this number seems completely wrong or somewhere close. Also I need to calculate the temperature which I need to heat ethylene to stay in the superheated vapour zone.
Thx in advance for your help..
Timewrap
I've got Ethylene gas at 15 deg C and 12 Kg/cm2(g) pressure and I'm letting it down to 1.5 Kg/cm2 (g). I'm trying to calculate the auto refrigeration of Ethylene at 1.5 kg/cm2 which I got from Hysys as -76 deg C. I think this temperatue is quite low. I've checked the P-H diagram and it indicates a much higher temperature.
Can you please give me a idea whether this number seems completely wrong or somewhere close. Also I need to calculate the temperature which I need to heat ethylene to stay in the superheated vapour zone.
Thx in advance for your help..
Timewrap





RE: Auto refrigeration of Ethylene
possibly you are doing something wrong with your simulator, I have not access to this tool so I can't comment, however my little Properties (see www.prode.com ) with SRK returns for Joule Thomson about 1.17 C/Kg/cm2 at input conditions (12 Kg/cmq , 15 C), for a dp of 10.5 Kg/cm2 I would expect about 13 C temperature drop, accordingly the H-P flash returns about 2.6 C , similar data from REFPROP (outlet temperature about 2.3 C), I hope this helps to identify the problem.
RE: Auto refrigeration of Ethylene
An isenthalpic expansion from 15o and 13 bar abs. to 2.5 bar abs results in about 2.5oC.
I suggest to use:
http
RE: Auto refrigeration of Ethylene
Thanks a lot for you time and for your responces..
Paolopemi - Can you please spare a moment to show that how you have used your table from www.probe.com to arrive at 2.3 deg C. Appreciate your help.
Pluto..
RE: Auto refrigeration of Ethylene
Properties (as REFPROP and other tools) can expose the methods directly in Excel so it's really a matter of few seconds to get these results, there is a free version which you can download from their site, however note that company is www.prode.com not probe,
hoping this helps.