Gas chromatography study of the adsorption of refrigerating fluids on microporous solid adsorbents

Adsorption isotherms for microporous solids have been determined by elution gas chromatography. Adsorbents are of ;molecular sieves' type; their utilization in affinity thermal machines is envisaged. These machines work in a relatively high domain of pressure for the adsorbate, so the chromatographic technique is generally inadequate for their study. The possibility of increasing the maximal pressures reached by chromatography has been investigated in relation with: the carrier gas flow rate, the length and width of columns, the injected adsorbate mass. This study has been made for different solid adsorbents (zeolite 4A and 13X, silica gel), in different shapes (small stick, pellet, powder), and with different adsorbates (water, methanol, ethanol). In the most favorable conditions that have been derived, the qualities of the chromatographic method, rapidity, simplicity and large range of measures, appear well fitted to the search of this kind of isotherms which does not require a great accuracy.