Calculate the density of hydrogen gas at 15 degrees Celsius and its density as a liquid; the resulting pressure of hydrogen in liquid form is low. Why? Where did it go wrong?
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To calculate the density of hydrogen in liquid form at 15 degrees, enter the following values: stream: hydrogen at 15 degrees, gas phase fraction of 0; method to be used: RK-SOAVE; block temperature: 15 degrees, heat load: 0. The calculation results are as follows: 123 B1 B1B1 LIQUIDVAPORMISSING Substream: MIXED Mole Flow kmol/hr H2 110 Total Flow kmol/hr 110 Total Flow kg/hr 2.015882.015880 Total Flow cum/hr 0.0669810.08525450 Temperature C 15 15 Pressure kPa 131334087.4234087.42 Vapor Frac 01 Liquid Frac 10 Solid Frac 00 Enthalpy cal/mol 26.0622328.24824 Enthalpy cal/gm 12.9284714.01286 Enthalpy cal/sec 7.239517.846732 Entropy cal/mol-K -12.19076-11.8719 Entropy cal/gm-K -6.047364-5.889192 Density mol/cc 1.49E-02 1.17E-02 Density gm/cc 3.01E-02 2.36E-02 Average MW 2.015882.01588 Liq Vol 60F cum/hr 0.05355780.05355780 I think the results are incorrect, but I’m not sure where the error lies The method is still wrong; why is the pressure of a liquid lower than that of a gas? But the density is about the same
The critical temperature of hydrogen is -239.97°C; there should be no liquid phase at 15°C. Last edited by tianshanxue on 2009-3-27 08:47.]
What was said upstairs is correct. This indicates that ASPEN PLUS has provided you with incorrect data; there should be no solution under the conditions you specified. If you use HSYS for the calculation, it will tell you that no pressure value can be found, and no pressure will be displayed.