Dissolution of gas in a stationary liquid layer: A diffusion-kinetic model and experimental studies

Abstract

An analytic model of gas dissolution in a stationary liquid layer is presented. This model considers for the first time the intrinsic kinetics of the process of gas dissolution in a liquid characterized by the rate of gas absorption/desorption reaction at the gas–liquid interface. Within the framework of the presented model, it is shown that the process of gas dissolution in a stationary liquid layer occurs either in the diffusion-kinetic regime or in the diffusion regime. In the diffusion-kinetic regime, the rate of gas dissolution in a stationary liquid layer is affected by both the intensity of gas diffusion through the liquid layer and the intrinsic kinetics of the gas dissolution process in the liquid; in the diffusion regime, the rate of gas dissolution in a stationary liquid layer is limited only by the intensity of gas diffusion through the liquid layer. Experiments were carried out to study the kinetics of methane dissolution in a stationary layer of water at different temperatures. From the comparison of calculated and experimental data, the values of the diffusion coefficient of methane in water were determined, and it was also established that the process of methane dissolution in a stationary layer of water occurs in the diffusion regime. A new empirical correlation for calculating the diffusion coefficient of methane in water in the temperature range from 273 to 323.15 K was obtained based on our and available data points: D[m2/s]=exp(−12.64−2250.5/T[K]).