correct thermo method for simulation
correct thermo method for simulation
(OP)
Dear all ,
wonder if anybody out there into simulation who can advice me on correct thermo method to use for a mixutre of components including H2 , N2 , methane , ethylene , butene, isopentane at 30 kg/cm2 g and 95 c fed to S&T exchanger .
the exchanger is cool enough to partially condense this mixure.
i have used one old version of proII , and set up a rigorous exhcanger module . i have tried a number of thermodynamic methods SRK ,t BK10 , GS ...ETC .
the liquid composition in the exchanger outlet oultet keep showing liquid H2 and ETHYLENE , i expect to see only pentane as liquid .
i have doubt the problem is in selecting a correct themo .
i would appreciate very much somebody 's advice .
thnx in advance .
wonder if anybody out there into simulation who can advice me on correct thermo method to use for a mixutre of components including H2 , N2 , methane , ethylene , butene, isopentane at 30 kg/cm2 g and 95 c fed to S&T exchanger .
the exchanger is cool enough to partially condense this mixure.
i have used one old version of proII , and set up a rigorous exhcanger module . i have tried a number of thermodynamic methods SRK ,t BK10 , GS ...ETC .
the liquid composition in the exchanger outlet oultet keep showing liquid H2 and ETHYLENE , i expect to see only pentane as liquid .
i have doubt the problem is in selecting a correct themo .
i would appreciate very much somebody 's advice .
thnx in advance .





RE: correct thermo method for simulation
The other components look similar enough to assume activity coefficients equal to one, at least for a first
pass calculation (could use UNIFAC to check it).
In that case Raoult's law can be used to calculate
the K (partitioning coefficients) values.
RE: correct thermo method for simulation
RE: correct thermo method for simulation
You should probably find a very low amount of H2/N2 in your liquid, both for numerical and thermodynamic reasons. In order to correctly predict the heat transfer coefficients when rating/designing the exchanger, you do need to have them in your simulation!
Try first a simple HX model, with fixed outlet temperature, and see what comes out. Then, if you want, use the rigorous method to figure out the performance of the exchanger, or contact a thermal rating engineer who can use HTRI or HTFS to design/rate the exchanger.
Regards,
Joerd