Numerical Study of Steam–CO 2 Mixture Condensation over a Flat Plate Based on the Solubility of CO 2.

In order to successfully study the condensation and separation of a steam–CO₂ mixture, a boundary layer model was applied to the mixture condensation of steam and CO₂ on horizontal and vertical plates. The modified condensation boundary layer model of steam and CO₂, given the CO₂ solubility in the condensate, was established, numerically solved, and verified with existing experimental data. Different condensation data of steam–air and steam–CO₂ mixtures were compared, and the effect of CO₂ solubility on the mixed gas condensation was analyzed under multiple pressure conditions (1 atm–10 MPa). The simulation data show that the presence of CO₂ will deteriorate the condensation heat transfer, just like air. Given that CO₂ is slightly soluble, some CO₂ can pass through the gas–liquid interface to enter the condensate film and reduce the accumulated CO₂ on the gas–liquid interface, which improves the condensation. However, the solubility of CO₂ is only significant under high-pressure conditions, inducing its effects on condensation. A comparison of the condensation coefficients of the steam–CO₂ mixture shows the lower impact of CO₂ condensation on the horizontal plate compared to that on the vertical plate. For most conditions, the steam–CO₂ mixture gas condensation heat transfer coefficient on the vertical plate surface is still larger than that on the horizontal plate surface, and the improvement in the condensation heat transfer coefficient caused by low CO₂ solubility (2 or 10%) at 10 MPa on the vertical plate is also larger than that of the horizontal plate. [ABSTRACT FROM AUTHOR]