Development of physico-chemical and hydrodynamic ways of heat and mass transfer intensification under the influence of self organisation in two phase systems

Exploitable results

Instabilities at the surface of liquids in contact with gases (Marangoni effect) substantially promote the rate of absorption of soluble component. A new theoretical model of interracial convection based on the positive feed back as the key mechanism of Marangoni instability caused by the liberation of heat at gas absorption was developed. Critical conditions (critical time of contact tcr critical Marangoni number Macr) for the development of intensive convective regime instead of slow diffusional one were calculated. The investigation into non-steady state absorption of different systems led to the new experimental results. It was found that the rate of absorption at t > tcr can be essentially higher than the rate of desorption even for a sparingly soluble gas. Experimental data are in good agreement with the theoretical model. This new effect can be important for biological and environmental systems. Investigation of interracial convection on different optical installations and the development of a new experimental technique for spectroscopy of interracial fluctuations during gas absorption with and without chemical reaction enabled us to make conclusion that microflows can arise at the interface after critical contact time of gas and liquid. In the vicinity of interface complex patterns of the local liquid velocity fluctuations develop but regular eddies similar to Benard cells escape detection. New methods and apparatuses in which the phase inversion conditions are self regulated over a wide range of flow rates have been developed as well as the design procedure including correlations for pressure drop and mass transfer rates calculation. The phenomenon of self-regulation of phase inversion conditions in irrigated packing and apparatus based on it can serve as a basis for creating compact chemical units e.g. for syngas clean up, for bromine and iodine desorption from natural brines by air desorption method. A unit of this type has been developed by us for styrene, phenol and formaldehyde removal from effluents by ozonization.

Exploitable results

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