Transient physical gas absorption in a stirred liquid using the surface renewal model of mass transfer. (28th April 2021)

• Record Type: Journal Article
• Authors: Huang, Hengshuo; Chatterjee, Siddharth G.
• Is Part Of: Chemical engineering science. Volume 234(2021)
• Publication Date: 2021-04-28
• Subjects: Gas absorption -- Diffusion -- Mass transfer -- Surface renewal model -- Unsteady state; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; Chemical engineering; Periodicals; Electronic journals; 660
• DOI: 10.1016/j.ces.2021.116449
• Languages: English
• ISSNs: 0009-2509

Abstract

Highlights: Rigorous surface renewal model for unsteady-state physical gas absorption. Model accounts for both the rate of gas absorption and dissolved-gas transfer. The two rates have an inverse relationship. The law of addition of resistances holds only under steady-state conditions. Theoretical validity of the linear driving force form of the mass-transfer rate only under certain conditions. Abstract: This work presents a rigorous surface renewal model for unsteady-state physical gas absorption in a stirred batch cell in which the concentration of dissolved gas in the bulk liquid is a function of time for zero and finite gas-phase mass-transfer resistance. Using experimental parameters from the literature for oxygen and hydrogen absorption in water at 25 °C and atmospheric pressure, predictions of the model reveal that the rates of absorption and dissolved-gas transfer to the bulk liquid exhibit an inverse behavior during the initial moments of absorption after which they merge into a single curve and decline with process time as the water becomes increasingly saturated with the dissolved gas. Predictions for the dissolved oxygen concentration made with the rigorous model compare excellently with those of the standard pseudo steady-state model used in the literature except for short time scales.