Effect of pressure on the stability and ability to drying of water-saturated gases

Abstract

The inorganic salts-based solid phase adsorbents are often used as driers of gases or weakly polar liquids (for example – ethanol) as the cations of metal elements have the ability to readily form aquacomplex compounds, which easily solidify and form crystalline hydrates. However, since there is often a need to conduct drying gas from other pressure than atmospheric pressure, there is a need to carry out the dependence of properties of inorganic salts, which form crystalline hydrates, from the pressure. Results based on the use of four different inorganic adsorbents have shown that the pressure increase accelerates dehydration and generally deepens its extent. It is caused both by van der Waals bonds and a more effective mechanism for the formation of bonds of the donor-acceptor mechanism. Effect of pressure increase on various adsorbents is uneven and is linked to the strength of relationships, which are formed by a cationic mechanism, and is also associated with coordination number of the central atom, its radius, the distance to its electron shells and the position in the periodic table. The results make it possible to develop an adsorbent for effective drying gas to replace traditional gas drier, such as phosphorus (V) oxide, and sulfate (sulfuric) acid.