Is there a temperature-composition table for butane and isobutane mixtures at certain pressures?
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Our unit installed a C4 liquefied gas facility for isobutane extraction last year; having such a chart would make things clearer to view. Thank you!
You can try using Aspen for simulation
If you have PROII or ASPEN simulation software available, it’s easy to view these material property parameters. If not, there’s no choice but to check the material property handbook.
This post was last edited by Hansonwen on 2018-9-7 at 16:58. I’ve drawn phase diagrams for isobutane and n-butane at several operating pressures (1 bar/2 bar/3 bar/4 bar) for your reference. In each phase diagram, the X-axis represents the molar fraction of isobutane (i-C4), while the Y-axis shows the bubble point/dew point temperature (TDEW indicates the dew point line, and TBUB indicates the bubble point line). These diagrams allow you to determine the molar fraction of isobutane in the liquid and gas phases under equilibrium conditions. By subtracting this value from 1, you can obtain the molar fraction of n-butane. For further assistance, you can tell me the operating pressure and temperature at the bottom and top of your reactor, and I’ll help you look it up
Thank you to the person above; the back pressure is 0.51 MPa and the top temperature is 45 degrees. We usually keep the temperature below the reflux point between 46.8 and 47.5 degrees. The isobutane product is required to have a purity of >99.87%.
“The so-called “temperature-Composition Table for mixtures at a certain pressure” is of very little help in solving your problem. When asking questions due to insufficient knowledge, one should present the original question without adding one’s own understanding. By taking a step based on your own understanding, you ended up going in the wrong direction; others’ answers cannot give you the result you want
Since I don’t know the flow rates and molar fractions of n-butane and isobutane when the feed enters the tower, I have calculated based on an assumption that each component of the feed accounts for 50%. The phase diagram is shown below; to achieve a product purity of 99.87% for isobutane at the tower top, the condensation temperature at the top of the tower should theoretically be controlled at 38℃