Evaluation of the effectiveness of countercurrent schemes of sodium-cationite filters in water softening processes
Abstract
Evaluation of the effectiveness of countercurrent schemes of sodium-cationite filters in water softening processes
Incoming article date: 28.05.2022The paper presents the results of evaluating the effectiveness of water softening using sodium-cationite filters with countercurrent modes of operation according to the flow schemes of purified water relative to the direction of supply of regeneration solution and washing water. The research was carried out at a pilot ion exchange facility using a single-stage sodium-cation scheme in laminar operation. It has been found that the flow from bottom to top under the resin layer leads to its compaction due to high hydraulic resistance, which in the case of water supply leads to an increase in softening efficiency, and the flow from top to bottom facilitates its passage through the resin layer due to low hydraulic resistance, which in the case of water supply increases the resin resource, and in the case of the supply of regeneration solution and washing water contributes to a more complete regeneration and washing of the layer from the residual amount of NaCl solution. A comparative characteristic of three grades of resins was carried out during two filter cycles with different countercurrent schemes. According to the results, the resins of the brands Purolite C100E and Tokem-150 are recommended for use in countercurrent circuits of filters for water softening.
Keywords: water purification, water softening, water hardness, hardness salts, ion exchange, sodium-cationite resins, resin regeneration, countercurrent regeneration, resin resource, resin regeneration degree