The surface tension gradient can result from releasing a surfactant from the liquid film or feeding a vapor into the liquid film, and the interfacial disturbance will be induced by them. The flowing phenomena were termed “Marangoni effect,” and the mass transfer performance was enhanced by the effect. The objective of this study was to apply the Marangoni effect, such as water vapors absorbed by the liquid film of triethylene glycol (TEG) solution, and to analysze mass transfer behaviors with and without surfactants’ addition in the liquid film. The interfacial disturbance resulted from the surface tension gradient was considered in this study, and the mass transfer behaviors for packed-bed absorbers were discussed to elucidate the influence of the Marangoni effect on the absorbers. It was observed that the trends of mass transfer rates could be increased significantly as the surfactant is added into the absorption system. Experimental results showed that feeding a vapor or adding a surfactant with lower surface tension and/or higher volatility in the liquid will result in the surface tension gradient on the gas-liquid interface. The induced flowing disturbance will lead to an increment of mass transfer rate for a gas-liquid contact system.

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Discussions of Effects of Surface Tension on Water Vapor Absorbed by Triethylene Glycol Solution Films

Indoor humidity can be adjusted by an absorption air conditioning system; however, reaching zero humidity is not absolutely the purpose of such adjustment. Therefore, one of the purposes of this st...

Optimization of operating conditions for energy conservation in a packed-bed absorber

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Teaching Essay-Writing from an ‘Appliable’ Linguistics Model

Theoretical analysis of the development of surface convection in the transient process of gas absorption by an initially motionless layer of liquid was carried out. The main resistance to mass transfer is concentrated in the liquid phase. Convective instability is caused by the temperature dependence of the surface tension. Linear analysis showed a strong dependence of the critical time on the viscosity of the liquid. On the basis of the simplified nonlinear model that does not use semi-empirical assumptions, approximate estimates of the critical time from physical characteristics are obtained. The problem was solved in a two-dimensional formulation. The concentration of the absorbed substance is represented as the sum of the three terms of the Fourier series on the coordinate directed along the gas - liquid interface. Equations for the temperature and the fluid velocity are linearized. Nonlinearity was taken into account only in the equations for concentration. The calculations are compared with known experimental data.

Thermocapillary instability in the nonstationary process of gas absorption. effect of lewis and prandtl numbers on the critical time

The process of gas absorption into initially motionless liquid layer is investigated. The convective instability caused by the temperature dependence of the surface tension. The critical time of transition of the process to unstable convective regime, as well as the intensity of mass transfer in a surface convection are estimated numerically. The mathematical model includes the equations of convective diffusion, thermal conduction and fluid motion. The problem was solved numerically in the two-dimensional formulation. In the coordinate along the interface the concentration of the absorbed substance is represented by three terms of the trigonometric Fourier series. A difference approximation of equations with an exponentially changing grid in the direction normal to the interface is used. The simulations results agree with the well-known experimental data on the absorption of carbon dioxide in water.

E F Skurygin

Papers

A simplified nonlinear model of the Marangoni instability in gas absorption