Research into the Possibility of Regenerating Silica Gel using Vacuum
Abstract
Gases used in industry must meet the required technological parameters for the production process, such as the content of gaseous impurities, moisture content and mechanical impurities. Their presence has a significant limiting effect for their further use in technical practice. One of the effective methods of removing moisture from gas is its adsorption, in which the gas passes through a bed of adsorbent, which subsequently binds this moisture on its surface. The article deals with the regeneration of this adsorbent, as it is advantageous from an economic point of view if it is possible to use this adsorbent repeatedly in the gas drying process. By reusing the adsorbent, there is an overall reduction in the cost of operating the equipment and the ecological burden caused by the production of a new adsorbent. The article primarily discusses the influence of the temperature of the dried medium on the speed of its regeneration using vacuum.
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Introduction
The currently growing pressure to reduce energy and production costs forces manufacturers to increase the efficiency of production processes. One of the parameters for achieving the highest possible efficiency of the production process is the use of basic materials with the highest possible purity to prevent unwanted effects during production. Among the most used technical materials in all branches of industry are technical gases, which are subject to strict technical requirements. The amount of moisture contained in these gases indicates their quality. As the amount of moisture contained in the gas increases, its quality decreases and therefore it is necessary to subject them to a drying process.
The drying process is a complicated physical process in which the liquid content of the substance is reduced by the effects of heat, without changing its chemical composition.
The essence of drying is the migration of moisture in the opposite direction to the sorption process. During the general drying process, moisture moves from the porous core of the material to the surface layers and into the surrounding environment, whereupon the moisture meets the drying medium, which carries it away.
To determine the most optimal drying conditions, it is necessary to know the physical laws and quantities that affect drying in the individual phases of the entire process, the input parameters and the required performances.
Conclusion
Vacuum drying wet material can significantly reduce its drying time due to the low-pressure environment. This lowers the boiling point of water, which accelerates the removal of free and bound moisture from the dried material. Thanks to lower temperatures, this method of regeneration prevents thermal damage or material degradation.
From the experiments presented in the article, it follows that vacuum drying is ideal for the desorption of moisture from silica gel at a temperature of 70°C, as the moisture bound on its surface is released faster. Lowering the temperature also results in an increase in the time required for the regeneration of the silica gel and its reintroduction into the gas drying process.
When designing a device used for the regeneration of silica gel using a vacuum, it is also necessary to consider the economic aspects of drying, as the provision of a vacuum system can mean significant financial costs, but the reduction of the drying temperature compared to classical methods gives the possibility of saving energy spent in the process of regeneration of silica gel.