HCL falling film absorber and azeotrope
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1. I would like to ask the experts: the azeotrope point between HCL and water is 20.4%. Why can absorbing HCL exhaust gas with water result in a concentration of 31%, while falling film absorption makes it easy to exceed this azeotrope point? 2. What’s not clear is whether the saturation level of water and HCL absorption simply needs to reach the theoretical solubility limit. I would like the experts to explain why absorption can enable us to exceed the azeotrope point by 20.4% What is theory?
Distillation is the equilibrium of distillation; absorption is the equilibrium of absorption
Distillation and absorption are two different processes. :)
Distillation is the desorption process for HCl; it involves a balance in the ratio of hydrogen chloride to water under boiling conditions； Filmwise absorption is an equilibrium between the hydrogen chloride concentration in water and the hydrogen chloride in the gas phase, established under lower temperature conditions based on the partial pressure of hydrogen chloride. The biggest difference between distillation equilibrium and falling film absorption equilibrium is that the temperature conditions in their equilibria are different.
It has been explained very clearly upstairs. If hydrogen chloride is absorbed by water at atmospheric pressure at the azeotrope temperature of 108.5°C, hydrochloric acid with an azeotropic composition and a concentration of about 20.4% can only be obtained ； If hydrogen chloride is absorbed at temperatures below this value, hydrochloric acid with a concentration higher than that of the azeotropic composition can be obtained. If the content of non-condensable gases in the absorbed hydrogen chloride gas is low, hydrochloric acid with a concentration greater than 40% can be obtained through absorption at temperatures below 20°C.