On the impact of non-condensable gases on condensation efficiency
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I have a question for the experts here: 3 kilograms of chloroethane vapor generally condenses at around 55 degrees. Currently, it contains 20% air, and simulations using software such as Aspen show that condensation begins only at 38 degrees; even at -10 degrees, there is still a small amount of chloroethane that has not condensed. Previously, circulating water at 32 degrees was used for condensation, but in those simulations no liquefaction occurred – everything remained in gaseous form. Is this reasonable? Why is there such a big difference with the non-condensable vapor? The property-based method is simply the ordinary PR equation
Just as there are no substances that are completely insoluble in water, it is also impossible to achieve a complete separation between air and condensable substances. Therefore, the presence of air affects the amount of condensation, but it generally should not affect the condensation temperature
It contains about 20% air, which means the partial pressure of the chloroethane gas is reduced by 20%; from an original pressure of 3 kilograms, it becomes 2.4 kilograms, so its boiling point decreases
But according to software simulations, the temperature drop is a bit too large. Originally, 55 degrees was sufficient for complete condensation; now, at 38 degrees, there is still no liquid phase. Is this normal?
There is a problem with the simulation; try adding a heat exchanger to limit the outlet temperature