Studies of Water-Vapour Adsorption Dynamics of High-Efficiency Desiccant Based on Aluminium Oxide and NaX Zeolite  
[PERSON]  
-regenerated and returned to the process. Clearly, the technical justification for contact-sorption drying depends on whether the sorbent can easily be regenerated and recycled [5]. As a rule, silica gel, active aluminium oxide, and zeolites are used as an adsorbent-desiccant of different gases, such as compressed air and hydrocarbon-containing gases [6; 7; 8; 9; 10; 11; 12; 13; 14]. It is known that zeolites possess some advantages over other adsorbents, in particular, a possibility of dewatering at low partial water pressures, a stable and high degree of dewatering, and a good mechanical strength. However, considering quite a high temperature of their regeneration, it is expedient to carry out dewatering, using a cheaper and more easily regenerated adsorbent, and deep final dewatering, using zeolites [6]. The use of metastable low-temperature forms of aluminum oxide for drying moisture-containing gases is due to their defective structure with many adsorption centers [15]. Desiccants based on aluminium-oxide are characterised by quick regeneration at temperatures in the range of 200-250 \({}^{\circ}\)C, by resistance to condensed moisture in humid environments, by high static capacity, relative easiness of obtainment, and accessibility of raw materials. When using aluminium oxide as a protective layer in the adsorber, condensed moisture and chemical impurities will be sorbed from gases upon it, including water vapour, and deep air dewatering will take place in the primary layer of the desiccant-zeolite. It can be expected that the use of a more efficient desiccant as a protective layer will allow not only protecting the primary layer against condensed moisture, but also enhancing the overall performance of the adsorber. It is known that the application of the energy saving method for obtaining a sorbent by means of thermal activation of gibbsite in reactors with a rotating heating surface without the use of traditional \"pneumatic transport\" leads to its cost saving, and the introduction of various modifying additions in the composition of the adsorbents, obtained by this technology, allows increasing the sorption capacity of aluminium oxides [16; 17; 18; 19; 20; 21; 22; 23; 24; 25; 26; 27]. It was previously shown [28] that the modification of the adsorbent desiccant, based on bayerite with potassium and sodium cations, at the stage of hydrating the products of thermal activation of gibbsite allows obtaining adsorbent desicants with high values of static (more than 20 g/100 g) and dynamic (more than 5.0 g/cm\({}^{3}\)) capacity with respect to water vapour. As a result of the optimisation of the conditions (the nature and the alkali content at the stage of hydration of the gibbsite thermal activation product and the acid module value at the stage of preparation of the moldable paste) of the desiccant preparation, a new desiccant was obtained that surpasses foreign and Russian analogues in dynamic capacity (DC) at similar values of the specific surface area (about 300 m\({}^{2}\)/g) and static capacity (20-22 g/100 g) [29]. The desiccant is characterised by high strength (more than 8.0 MPa). The necessary stage in the research works is scaling when proceeding from laboratory to industrial solutions in order to minimise risks, and to test the technology in conditions modelling the industrial ones. When calculating adsorption apparatuses for various purposes, the static, kinetic and dynamic characteristics of adsorption processes are taken into account. One of the main tasks in the design calculation of the adsorber is to determine the adsorption capacity for specific conditions of the processes. The dynamic capacity of the adsorbent layer acts as such characteristic. This paper presents the results of the experimental studies on water-vapour adsorption using a pilot installation applying an industrial desiccant-zeolite NaX-and a developed, highly efficient adsorbent based on aluminum oxide.