RU2345958C1 - Method for water softening - Google Patents

Abstract

FIELD: technological processes; chemistry.

SUBSTANCE: method consists in water softening by its alkalisation in the first container at partial pressure of carbonic acid gas that exceeds the equilibrium pressure, crystallisation of calcium and magnesium salts in the second container at sharp drop of pressure in the presence of caproic fibers, at that regeneration of filter from caproic fibers is realised by means of their periodic shaking and flushing of processed water through nozzle of deposit discharge.

EFFECT: higher extent of water hardness reduction, higher quality of caproic cloth filter regeneration.

2 cl

Description

The invention relates to a water treatment technology, in particular to methods for producing water that does not contain hardness ions, and can be used both independently to soften highly saline waters and as one of the links in the technology for producing deionized water.

A known method of treating wastewater from organic impurities by passing the treated water through a filter with a fiber loading and the use of inert synthetic fibers for this purpose [1]. This method allows to reduce the content of oil products and suspended particles in wastewater. Fiber regeneration is carried out by washing with a reverse current of water.

The disadvantage of this method is not a sufficiently high degree of reduction in the rigidity of the treated water.

There is also known a method of water purification, in which the removal of hardness ions from natural waters is carried out in a reactor by crystallization of hardness ions on the surface of an inert filter by adding a solution of lime or alkali [2].

The disadvantages of this method of water purification are difficulties in the selection and preparation of inert granular material, as well as the inability to obtain low hardness values of the treated water.

Closest to the proposed is a method of water softening, including alkalization, crystallization of impurities of calcium and magnesium salts and filtration by passing water through nylon fibers [3]. The regeneration of kapron fibers is carried out by a reverse flow of waste water.

The disadvantage of this method of water softening is the low degree of reduction in the hardness of the treated water, the need to stop the continuous process of water treatment for the regeneration of nylon fibers, as well as their incomplete cleaning.

The basis of the proposed method of water softening is tasked with increasing the degree of water hardness reduction, as well as raising the quality of regeneration of a filter made of nylon fibers.

The problem is achieved in a method of water softening, including alkalization, crystallization of calcium and magnesium salts and filtration through nylon fibers, in which alkalization of the treated water is carried out in a first container at a partial pressure of carbon dioxide above equilibrium, and the precipitation of calcium and magnesium salts on nylon fibers is carried out in the second container with a sharp decrease in pressure, while the filter is regenerated from kapron fibers by periodically shaking them and rinsing with a stream treated water through the pipe drainage sediment, and part of the precipitate formed is returned to the first tank.

It is known that the violation of carbonate-calcium equilibrium with a sharp drop in the partial pressure of carbon dioxide in water leads to massive crystallization of calcium carbonate both in the water column and on the surface of the seed material [4-6].

In the proposed method, alkalization is carried out in the first container, in which calcium carbonate balance is not disturbed. In the second tank, a sharp drop in pressure occurs and mass crystallization takes place in the presence of a developed surface of kapron fibers, as a result of which the bulk of hardness salts precipitates as a solid precipitate both in the water column and on the surface of kapron fibers. Periodically, as the solid phase of hardness salts accumulates in the second container, the nylon fibers are shaken and the stream of treated water is removed through the sediment discharge pipe. To increase the total surface on which hardness salts are deposited in the second tank, a part of the precipitate is returned to the first tank and together with water enters the second tank in order to increase the amount of hardness salts precipitated during mass crystallization.

In the proposed method, water softening can be carried out continuously without stopping the equipment for washing nylon fibers with a reverse flow of waste water.

Thus, alkalization of the treated water in the first tank at a partial pressure of carbon dioxide above equilibrium, deposition of calcium and magnesium salts on nylon fibers in the second tank with a sharp decrease in pressure and regeneration of the filter from nylon fibers by periodically shaking them and washing them with a stream of treated water through the outlet pipe sediment can increase the degree of reduction of water hardness, as well as improve the quality of regeneration of the filter from nylon fibers.

Information sources

1. Verbin V.A., Petrovsky O.V., Panov V.P. Fiber-loaded filter for wastewater treatment. Bulletin NTI Central Research Institute inform. and those. ek. Ferrous Metals Research, 1981.

2. Graveland A. Water softening using reactors loaded with granular materials. - American Water Works Association, 1983, v. 75, No. 12, p. 619-625.

3. A method of softening water. Gnusin N.P., Zabolotsky V.I., Alekseeva S.L., Grishin V.I. RU 02027679 C1, 19950127, C02F 1/42, C02F 5/00.

4. Nathanov H.H. Preparation of geothermal water for use. - M.: Stroyizdat, 1980.

5. Tskhvirashvili D.G., Tevzadze N.U., Kalabegashvili N.G. The formation of carbonate and salt deposits in the circuit of plants. - In the book: Alternative energy sources: Materials sov.-ital. symposium C.Z. M .: ENIN, 1983.

6. Akhmedov R.B., Novikov B.E., Akhmedov G.Ya. Stabilization treatment of geothermal water by introducing seed particles // Industrial Energy, 1985, No. 10, p.61-64.

Claims (2)

1. A method of water softening, including its alkalization, crystallization of calcium and magnesium salts and filtration through nylon fibers, characterized in that the alkalization of the treated water is carried out in a first container at a partial pressure of carbon dioxide above equilibrium, and the precipitation of calcium and magnesium salts on nylon fibers is carried out in the second tank with a sharp decrease in pressure. 2. The method of water softening according to claim 1, characterized in that the filter is regenerated from kapron fibers by periodically shaking them and washing them with a stream of treated water through a sediment discharge pipe, and part of the precipitate formed is returned to the first container.