SU1766501A1 - Method for regeneration of anion and cation exchanger filters at the first step of water-desalinating plant - Google Patents

Abstract

Usage: in heat and power engineering to obtain desalting water. SUMMARY OF THE INVENTION: Regeneration of anion exchangers and cation exchangers of a desalting plant is carried out by passing through the filters first spent regeneration solutions of these filters to the previous regeneration in an amount that ensures recovery of 20-80% of the working exchange capacity of ion exchangers, then the corresponding spent regeneration filters of the mixed effect steps of ionization with remote regeneration in an amount that ensures full restoration of the working capacity and itov.

Description

The invention relates to methods for the regeneration of ion-exchange filters and can be used in heat and power engineering and other industries using desalinated water.

The closest to the proposed invention in terms of its technical essence and the achieved result is the regeneration of anion-exchange and cation-exchange filters of a desalting plant, which consists in passing recycled regeneration solutions of the corresponding filters of the previous regeneration through ion-exchange filters to ensure the recovery of 20-80% of the working exchange capacity ionites, then solutions of alkali and acid, respectively.

The disadvantage of this method is the need to use fresh alkali and acid.

The aim of the invention is to reduce the consumption of reagents and the elimination of aggressive wastewater desalting plant.

The method is carried out by passing through the filters first spent regeneration solutions of the corresponding filters of the previous regeneration in an amount that ensures recovery of 20-80% of the working exchange capacity of the ion exchangers, then pass the appropriate spent regeneration solutions of the mixed-action filters with the external regeneration through the filters, ensuring full recovery of the working exchange capacity of ion exchangers.

In filters of mixed action, used as the last stage of ionization, the specific consumption of reagents per 1 m of the corresponding ionite is usually taken equal to 70 kg HaSO-q and

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100 xrNaOH. Sulfuric acid solutions are used at a concentration of 3-5%, the regeneration of the anion exchanger is carried out with 4% NaOH solution. In the mixed effect filters used for desalting condensates, the cation exchanger is regenerated with a 3-4% H2SO4 solution at a specific consumption of 100% H2 S04 80 kg / m3; Anchorage is regenerated with 4–5% solution of NaOH at a specific consumption of 120 kg / m. Spent perefrepia itVibViH bie dissolve) neutralize and drop. s

The method is carried out as follows.

Spent regeneration solutions of mixed-effect filters with remote regeneration of a desalting plant or operating in parallel, resulting from separate regeneration of the cation exchanger and anion exchanger are collected in the respective tanks of acidic and alkaline solutions.

In anionite and cationite filters, after recovering 20-80% of the exchange capacity of the cationite and anionite according to the method given in the prototype, the remaining 80-20% is restored by passing acid or alkaline solutions from the tanks, respectively, after regeneration of the mixed-action filters.

PRI me R. Under laboratory conditions, a mixed filter operation process was modeled. The column was loaded with a contact mixture consisting of equal volumes of cation exchanger and anion exchanger. KU-2-8 was used as the cation exchanger, AB-17-8 as the anion exchanger. Water of degraded quality with a salinity of 1.5 mEq / kg was supplied to the mixed action filter. The need to use water with increased salinity is due to several reasons. First, the modeling of desalting processes in mixed action filters with low salt content under laboratory conditions is difficult due to the long duration of this process.

Secondly, during the operation of power plants, conditions may be created under which impurities may enter the condensate through the leakages of turbine condensers, which increase its salinity.

The working cycle is terminated when the quality of the filtrate in terms of salinity approaches the maximum permissible values.

The control was carried out according to the following pH parameters, chlorine sulphate ion content, hardness, electrical conductivity. With

This mean chlorine ion leakage was 1-1.5 mg / l. According to the experimental data obtained, the capacity of the cation exchanger and anion exchanger with deep desalination of water with a salinity of 1.5 mEq / kg is 180 ± 20 g eq / m3. During the filtration cycle, the pH of the filters decreases from 6.94 to 4.3; an increase in electrical conductivity from 4.9 µS / cm to 11.0 µS / cm; content

Chlorides in the filtrate during the filtration cycle increased slightly to 0.5–1.0 mg / l, and only at the end of the filter cycle there was a sharp increase in their content in the filtrate from 1.0 mg / l to 5.3 mg / l.

To regenerate the cation exchanger, a 2% solution of sulfuric acid was used with a specific consumption of 2.5 gEq / gE. For the regeneration of anion exchanger - 4% sodium hydroxide solution also with a specific consumption of 2.5 g

eq / eq.

In order to simulate the H and OH ionization processes in the laboratory, the columns were filled with, respectively, cation SC-1 and anion exchangers AN-31. Cationite

triggered before the leakage of sodium ions into the filtrate 0.1 mg SQV / kg. Regeneration of the cation exchanger was carried out by passing through it the spent solution of the previous regeneration with recovery of 50% of the working exchange capacity of the resin.

Then, the spent solution of regeneration of the cation exchanger of the mixed action filter was passed until the acidity appeared, after which it was sent to the tank for the spent solution until the next regeneration. In this case, the exchange capacity of the cation exchanger was 470 ± 20 g.Eq./m3, 50% of which was restored in each cycle by the spent regeneration solution of the cation exchanger.

filter mixed action.

The AN-31 anion exchanger was triggered before the chlorine anion slipped into the filtrate 0.1 mEq / kg. The regeneration of the anion exchanger was carried out by passing through it the spent solution of the previous regeneration (according to a known method) with the restoration of 30% of the exchange capacity with the used regeneration solution of the previous regeneration, then the passed

the regeneration solution of the anion exchanger of the mixed action filter until the appearance of alkali, after which it was sent to the tank to collect the spent solution until the next regeneration. In this case, the exchange capacity

the anion exchanger was 1080 ± 20 kW / m3, 70% of which was restored in each cycle with a spent regeneration solution of an anion exchanger of a mixed-action filter.

The advantage of the proposed method of regeneration of ion-exchange filters in comparison with the prototype is the elimination of the use of fresh reagents: sulfuric acid and sodium hydroxide. For this purpose, used regenerated filter solutions of mixed action are used.

Such technology, in addition to reducing the consumption of reagents by a desalting plant, allows reducing the discharge of aggressive wastewater into water bodies.

Claims (1)

Invention Formula The method of regeneration of anion-exchange and cation-exchange filters of the first stage of the desalting plant, including passing through the last first spent regeneration solutions of the corresponding filters of the previous regeneration in an amount that ensures recovery of 20-80% of the working exchange capacity of the ion exchangers, and then the alkaline and acid solutions in the amount before restoring the remaining 80-20% of the part of the tank, characterized in that, in order to reduce the consumption of reagents for regeneration and eliminate the dumping, aggressive x drains, as the alkaline and acid solutions used spent regeneration solution after regeneration remote anionite and cationite loading filter of the last stage mixed bed demineralizer ionirovani.