A new method of disposal of concentrated solutions by crystallization of their components

Abstract

Purpose. Creation of highly efficient evaporators based on materials with capillary properties and energy of solar radiation. Methodology. The processes of evaporation from the surface of cotton, silk and linen fabrics were studied in the natural environment. The necessary equipment in the simplest case is a cloth, fixed vertically and immersed in the lower end of the concentrate. Tap water and NaCl solutions with a concentration of 100 g/dm3 were used as model solutions. Findings. Among modern methods of liquid waste disposal in the form of concentrates from various industries, thermal methods have become the most widespread, which are not critical to the chemical composition of concentrates and allow converting them into a solid state. On the other hand, thermal methods require significant energy costs, which makes the accumulation and storage of concentrates more cost-effective, despite environmental problems. Therefore, research in the field of reducing energy costs through the use of solar energy is extremely important today, especially in the context of global warming. Since it is difficult to raise the ambient temperature with large concentrates, we have proposed to increase the evaporation rate by increasing the evaporation area. To carry out this process, fabric with capillary properties were selected, due to which the liquid phase is able to rise to significant heights. In some cases, the intensity of evaporation can be increased by several orders of magnitude. Originality. The paper substantiates the possibility of using this method for evaporation of liquids and crystallization of substances contained in concentrates. The influence of temperature on the height of liquid rise through fabric capillaries and the influence of salt concentration on the intensity of their crystallization are studied. The influence of the fabric thickness on the crystallization intensity of the constituent concentrates is studied. Several designs of crystallizers are proposed, which allow increasing the efficiency of the evaporation process, automating the stages of solid phase removal and fabric regeneration. Practical value. The proposed designs of evaporators are ready for application in industrial enterprises and are especially effective in areas with warm temperatures throughout the year.