Calculate the bubble point pressure of multi-component systems! !
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The composition of a certain mixture is: cis-2-butene 0.19, trans-2-butene 0.31, isobutane 0.18, and n-butane 0.32. Calculate the bubble point pressures of this mixture at 0°C, 10°C, 20°C, 30°C, and 40°C.
It is unclear what the purpose is of the original poster’s calculation of the bubble point pressures of the mixture at these 4 temperature points. Since the normal boiling points of these C4 components in the mixture differ not significantly, the bubble point pressure of this mixture is relatively close to the vapor pressure of the most volatile component, isobutane. In engineering practice, the vapor pressure of isobutane can be used as an approximate value for the mixture’s bubble point pressure without causing any fundamental problems. The bubble point pressure value obtained in this way is slightly high; it can be considered as a design or operating pressure margin to accommodate variations in composition. The vapor pressure of isobutane at 40°C is 0.53 MPa (A); if the bubble point pressure of the mixture is 0.50 MPa (A), this does not constitute a significant difference when considering engineering aspects.
This post was last edited by Huàshí Dōng on 2022-7-27 at 14:46 :victory:
Simply generate the phase diagram in HYSYS, or use the bubble point data