Film−Penetration Model for Nonisothermal Physical Gas Absorption

Abstract

A two-parameter model, which utilizes the hybrid film−penetration concept, is developed for describing exothermic physical absorption of a gas into a liquid. The model is applied to the absorption of dry saturated water vapor into aqueous lithium bromide solution, which system is used in absorption cooling. The conventional film and penetration models predict constant values of 0.55 and 6.59 K for the interfacial temperature rise, respectively, and also suggest that the rate of absorption at the gas−liquid interface will be depressed by 3 (film model) and 40% (penetration model) compared to assumed isothermal absorption at the bulk liquid temperature. The holistic film−penetration model resolves this large discrepancy between the film and penetration models, which are fragmentary perspectives of the absorption process.