Interactive porous particles - Physical adsorption interactions

In many industrial processes, the transport and transfer of fluids within porous particles takes place in the absence of chemical transformation. This is particularly true of adsorption columns, certain chromatographic columns, drying operations for porous natural products, etc.

In this dossier, we will focus on analyses of porous media representative of synthetic adsorbents, where adsorbent particles (a few millimeters in size) are obtained by agglomeration of microcrystallites (a few micrometers in size) that are also porous.

This is particularly true of certain aluminas, activated carbons and molecular sieves (figure 1 ).

In this case, we need to distinguish between diffusional transfers within the microcrystallites and those observed in the pore volume outside the microcrystallites, which represents the particle's macroporosity, while the pore volume of the microcrystallites corresponds to the particle's microporosity.

Ultimately, this dossier will be limited to a simplified analysis of adsorption in the case of an adsorbent particle obtained by agglomeration, placed in a flow. For a description of the various industrial adsorbents, their physico-chemical characteristics and industrial adsorption processes, please consult the Adsorption section of the Génie Chimique treatise. For further theoretical information on these aspects, please refer to D.M. Ruthven's , on which we have based our work.

Finally, adsorption is an exothermic phenomenon. As a result, an exchange of thermal energy between the particle and the external medium may occur. In 2 , we will consider the case where heat transfer resistance is negligible (isothermal adsorption). The study of non-isothermal adsorption will be presented in paragraph