Gas-liquid separation problem in PROII
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The gas contains a small amount of water, a large amount of CO2, and small amounts of H2 and N2. The goal is to cool the gas by compression in order to liquefy the CO2, and then use flash separation to separate the gas from the liquid. However, I’m not sure which kinetic equation to use, as high pressure and phase changes are involved; therefore, the usual equations related to ideal gases cannot be applied. I’m a beginner, so please give me some guidance. This post was last edited by suiran983527 on 2009-2-11 at 14:39
I haven’t done it specifically. Personally, I think using the BWRS equation is more appropriate.
Since I have not worked with this system before, I tried several thermodynamic methods under certain temperature and pressure conditions: SRK, GS, BWRS. The calculation results varied among these methods. By reviewing the reports, it was found that the SRK method provides the most comprehensive set of interaction parameters. I hope the original poster can provide details about the specific conditions, so that we can select the most appropriate thermodynamic method. Or the most direct and effective method is to compare it with the actual situation, and choose the thermodynamic approach that is closest to reality.
Thank you for the hint. The process is as follows: ----> Compressor 1 ---> Flash ---> Compressor 2 -----> Stream out. Parameters at the compressor inlet: Property, Value, Units; Stream Name: S4; Stream Description: Phase, Vapor Temperature: 50.000°C; Pressure: 2214.000 kPa; Flowrate: 382.487 kg-mol/hr; Composition: H2: 0.106, CO: 0.017, CO2: 0.791, N2: 0.080, H2O: 0.006, COS: 0.000, CH4: 0.001, H2S: 0.000. The compression ratio of Compressor 1 is 3.5, and the temperature is reduced to 120 degrees; during the flash process, the temperature drops to 20°C. Steam (probably H2, CO2, N2) flows upward, while the liquid phase, which should be CO2, flows downward. Please help me check – logically, both the temperature and pressure conditions are suitable for a liquid phase; I think the wrong equation was used, which is why no liquid phase is formed