Estimation of the effectiveness of using sodium-cation exchange resins in the process of water softening for the operation of heat producing plants

Summary

The results of estimating the effectiveness of removing hardness salts from water by the ion exchange method using various sodium-cation exchange resins with the aim of using softened water to feed heat producing plants are presented. The studies were carried out in an ion exchange pilot plant using a single-stage flow scheme of sodium cationization in laminar conditions. The experiments involved determining the dependence of the softening efficiency on the water flow rate until the resource exhaustion of each of the resins with the subsequent regeneration and repeated studies of the effectiveness at different flow rates. It was established that sodium-cation resins provided for a high degree of removing hardness salts. At the same time, higher results in terms of the softening efficiency and degree of regeneration were obtained with Purolite C100E and Tokem-150 resins. Based on the results of the studies using these trademarks of resin for water softening as part of multi-stage water treatment plants at thermal power plants and boiler houses was proposed.

Key words

ion exchange , regeneration , water softening , hardness salts , heat producing plant , sodium-cation exchange resins

DOI 10.35776/MNP.2020.01.01

UDC 628.16:62-278

Pervov A. G., Golovesov V. A., Spitsov D. V., Rudakova G. Ya.

Ways of reducing the operating costs of membrane units
for the preparation of drinking water from underground water sources

Summary

Experimental investigations have been conducted to determine the main process parameters of membrane units (filtrate yield, the rate of scaling on membrane surface). Basing on the results of the experimental studies the total costs of purification of underground water of various chemical composition were obtained. The studies were conducted on laboratory benches with the use of nanofiltration membranes with various selectivity rates. The consumption of service chemicals and operational costs for the equipment were calculated by the software designed earlier by the authors for determining the process parameters of membrane units. While designing membrane units, nanofiltration membranes with low values of selectivity, power consumption and expenditures for chemicals are preferred. The dependencies of the calcium carbonate scaling rates on membrane types and the multiplicity of volumetric concentration of source water were obtained. A comparison of costs shows that the use of membranes even for cases of water deferrization is more economical than the known traditional technologies.

Key words

calcium carbonate , ground water , concentrate , reverse osmosis , nanofiltration , water softening , scaling on membranes , deposits of slow-soluble salts in water , scaling inhibitors , scaling rate

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UDC 661.183.12
DOI 10.35776/VST.2023.08.03

Pavelkova Anna, Spitsov D. V.

Current state of the ion exchange resin market (a review)

Summary

Widespread use of ion exchange plants for both natural water and industrial wastewater treatment is driven by the use of various ion exchange resins. It provides for selecting a unit for both complete desalination of water and selective purification depending on the demands of work. The main fields of ion exchange application are considered. The specific features of ionite selection are analyzed depending on the type of filter regeneration, filtration mode and rate. The lack of a unified classification of ion exchange resins hampers their optimal choice since the very name gives no idea of their properties, which requires careful study of the characteristics. A comprehensive analysis of the current ionite market according to the classical classification, their interchangeability, possible import phaseout has been executed. The optimal choice of an ion exchange resin with the minimum cost of the treated water is made after a comprehensive analysis of the quality indicators of the treated and source water, filtration mode, type of the plant.

Key words

selectivity , desalination , water softening , ionites , cationites , anionites , chemical softening of water , demineralization

DOI 10.35776/VST.2022.03.02
UDC 628.164

Kasatochkin A. S., Larionov S. Iu., Panteleev Aleksei, Riabchikov Boris, Shapovalov Dmitrii, Kharitonov Nikolai, Shilov Mikhail

Comparison of the options of systems for adjusting the salt composition of water from underground sources

Summary

Underground water sources with a high content of hardness salts are often used for drinking water supply. To achieve drinking water quality reducing its hardness is required. Known methods of softening result in the formation of a significant amount of liquid and solid wastes, i. e. mineralized wastewater or sludge that cannot be disposed of. Chemical water softening in clarifiers is used quite rarely owing to the difficulty of preparing chemicals, maintaining the constant required water temperature, and the complexity and maintenance of the equipment. In the 1990s, the technology of chemical softening in intensified reactors (vortex and blanket) was developed that gained widespread use in drinking water supply. Such units are quite frequently used in Europe and USA. At present Mediana-Filter Research and Production Company JSC is taking on the task of designing and testing reactors of this type. They have a high specific output of 50–100 m³/(m²·h), and their maintenance is much easier compared to clarifiers. The capacity of such plants reaches thousands of cubic meters per hour. Their main advantage is the elimination of liquid discharges and generation of solid wastes that can subject to utilization, while the yield of clean water is about 100%.

Key words

potable water , reverse osmosis , suspended layer , pilot plant , chemical softening , water softening , contact media , calcic pellets , fluidized bed , intensified reactor , dynamic softening system , sodium cycle