Parameters of gas dissolution in liquids obtained by isothermal pressure decay

A rapid and effective data analysis and interpretation approach is developed and validated for simultaneous determination of the film‐mass‐transfer and diffusion coefficients from time‐limited experimental data obtained by dissolving gas in liquids by the pressure‐decay method under isothermal conditions. Whereas previous approaches require experimental data until equilibrium and only determine the diffusion coefficient, accurate and rapid estimation of both parameters are achieved using a shorter set of time‐limited data, thereby reducing the errors owing to swelling by significant gas dissolution at later times. The equilibrium conditions can be predicted theoretically stemming from an analysis of the time‐limited data. This provides the estimates of the equilibrium pressure and gas solubility. This methodology not only yields accurate parameter values, but also alleviates the sufficiently large‐time collection of pressure‐decay data needed to essentially achieve equilibrium. © 2008 American Institute of Chemical Engineers AIChE J, 2009