DETERMINATION OF THE EFFECTIVE TRANSPORT-COEFFICIENTS FOR THE SEPARATION OF BINARY-MIXTURES OF ORGANIC-COMPOUNDS INTO PACKED THERMAL-DIFFUSION COLUMNS

Thermal diffusion in packed columns (TPC) is a process that could be u sed in the industry of separation, but some phenomenological aspects o f this phenomenon are yet to be studied. This paper presents the resul ts from physical investigations confronting experimental data to quant itative tools (analytical solution, computer model). It is shown that the classical approach of TPC with the transport coefficients measured in static conditions is irrelevant, especially for the thermal diffus ion coefficient, and that the efficiency of TPC is strongly governed b y the dynamics of porous packing. The hydrodynamic state in the column s impacts on the molecular diffusion coefficient (the well known hydro dynamic dispersion phenomenon) but also in a similar way on the therma l diffusion coefficient, and the existence of a thermodiffusive counte rpart to hydrodispersion is probable. A rational methodology for the e xploitation of TPC experimental data with an analytical solution and a computer model is proposed. Copyright (C) 1996 Elsevier Science Ltd