SU1328987A1 - Method of regeneration filtering elements of precoat filter - Google Patents

Abstract

The method of regeneration of filtering elements is used to clean the elements of alluvial ionite filters from particles of ion-exchange filtering material clogging them and contamination | H. The method allows to exclude the irreversible blocking of filter elements and to ensure their complete cleaning. This is achieved by first treating the elements with a chemical reagent that dissolves particles, conducts a shock regeneration in the reagent medium, and rinses with water. Then, after emptying the filter from the water, the cartridges are supplied to the air heated to a specific flow rate of 18 m of filtering surface. Air is supplied for 15 minutes, after which the filter housing is filled with water and additionally carried out shock regeneration. 1 il. with S (L her y 00 with 00 -Nl

Description

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The invention relates to the field of filtering, in particular, to methods of regeneration of filtering elements of alluvial filters and can be used in washbasin ion filters (NIF) used for water purification at nuclear power plants, as well as in other industrial sectors.

The purpose of the invention is the restoration of the filtering ability of the elements during the regeneration of the alluvion ion-exchange filter.

The method is explained in the drawing.

A solution of a chemical reagent dissolving soil particles on the cartridges is poured into the case of the 1 Iam filter which is to be regenerated. For filters used in nuclear power plants, typical are - pollution in the form of oxide and metal hydroxide, which are corrosion products of equipment materials and pipelines. To remove them, the filter housing is filled with a solution of nitric acid heated to 60 before the transfer. If the filter is made of carbon steel, then a 5% solution of oxalic acid is used as a chemical reagent. This process can be carried out by bubbling with compressed air, which contributes to a more efficient interaction of the phases, and also has a mechanical effect on the removable contaminants. As a result of treating the reagents with the reagents, the contaminants acquire an amorphous fragile structure, decrease in size and dissolve.

For final removal of contaminants from the surface of the filter elements after treatment with chemical reagent 8, shock regeneration in the medium of the chemical reagent is carried out for 4-6 hours. Owing to the hydraulic impact and energy of the water jets of some of the contaminants that occur during this operation, they are removed from the surface of the filter elements. However, the chemical reagent, the contaminated solution, does not interact with particles of ion exchangers stuck in the holes of the filter elements, therefore, after the described treatment. It is necessary to carry out an operation to remove ion exchangers. In this case, the filter elements are dried with air heated to temperature no higher than 90 ° C. after che289872

This filter is filled with water and additionally carried out shock regeneration in water.

A characteristic feature of synthetic ion exchange resins (ion exchangers) is their ability to swell in water and other liquids.

When washing and filtering, swollen particles of ion exchangers are naturally used, and it is in the swollen state that they penetrate and clog up the filtering electrodes (-1ent.

The process of swelling of ion exchangers is reversible and after drying the grain, they acquire the same size. Drying of the ion exchanger particles is carried out using a stream of hot air.

Before drying, the filter is free of 2d residues of chemical reagent

rinsing with water. Washing with water is a necessary operation, since during the subsequent drying, the residue of the reagent held on the surface and the ampholes of the fitting elements will dry out. As a result, crystals of the reagent are found in them, which subsequently prevent removal of particles of ion exchangers. 30 After washing, the filter is emptied and fed into the inside of the filter elements in the direction of the brotherly direction of filtering air heated to a temperature not. If the particles of the ion exchanger are dried with air at a lower temperature (e.g., room temperature), then the air flow is about 5 times proportional to the temperature difference, which will require considerable expenses, associated with the creation and operation of a gas cleaning unit with increased productivity. This is especially undesirable in the production of g that require special expensive gas cleaning, for example at nuclear power plants.

The upper limit tag of the permissible limit is caused by several reasons.

Ion exchange materials have limited thermal stability. So, annonite AB-17 ,. use n. in NYF, at temperatures above begins to decompose. Thermal destruction, accompanied by the melting of the iontsta grains, leads to their attachment to the surface of the filtering elements and the irreversible clogging of the filter.

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In addition, the air heated to too With, heats up to this temperature and the internal surface of the filter. When the filter is subsequently filled with water, it boils up to form a large amount of steam, which, when it enters the treatment plant of the evacuation system, moistens the filter walls of the gas cleaning filters. As a result, their resistance dramatically increases and productivity decreases.

Experiments on optimization of the regeneration process and selection of the drying mode with the lowest air flow are presented. The filter elements are filled with ionite grains, after which air heated to 90 ° C is fed into the filter, while its hourly flow rate, drying time and air volume spent on drying are recorded.

The results of the experiment are shown in the drawing, where the solid line shows the dependence of the drying time on the specific air flow rate (l / h per 1 cm of filtering surface), and the dash line shows the volume of air consumed per c.yuiKy at a given flow rate. As can be seen from the above data, the curve b of the discharge of consumed air has an extreme maximum point with branches descending from it. Modes to the left of the maximum point are characterized by a short drying time and a relatively small volume of spent air; However, these regimes cannot be recommended due to the very high specific consumption of the goat spirit. So, with a drying time of I min and a volume of spent air of 18 liters, it is equal to 37.4 l / h-cm or 374 m of filtering surface. If we take into account that the filtration area of an alluvial ion-exchange filter of a NPP can reach 50 m or more, then it is obvious that it is inexpedient to use such modes. . .

The modes to the right of the maximum point are characterized by a gradual decrease in the volume of air consumed with a simultaneous increase in the drying time. On this part of the curve, there is also a characteristic point 1, after which a decrease in the volume of air flow does not occur, and the duration of the process increases. When working on modes to the left of the point

0

1 there will be an excess of air, and on - an increase in the drying time without a decrease in volume. Therefore, point 1 xa-s indicates the optimal parameters of the process, at which it is recommended to carry out the drying with preheated air, to maintain a specific flow rate of 18 nm / Hm of filtering surface for 15 minutes. Since during the drying process, partial removal of the grains from the gaps will occur, the direction of air movement is chosen in the opposite direction of filtration so that the blown particles do not fall inside the filter elements.

After drying, the apparatus is filled with water and additional half-bodies are subjected to shock regeneration. Its use allows you to completely remove particles of ion exchangers from the gaps and restore the filtering ability of the elements. The filling time should not exceed 2-3 hours in order to avoid repeated swelling of the particles.

It is worth noting the importance of the procedure for performing basic operations during regeneration. In the prototype method, the filter material is first removed and then contaminated. According to the proposed method, the impurities are first removed by their 1P solution, and then drying and removal of the ion exchanger grains. This is due to the fact that, in the reverse order, the impurities, which stick to the surface of the filter elements and the ion exchangers, also dry up with the ion exchanger. The removal of ion exchanger 0 from the holes in the subsequent shock regeneration becomes difficult.

Example 1. Filtering filter elements with a filter area of 0.5 m are clogged with ion exchange particles and

five

0

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is present in the source water by contaminants in the form of iron hydroxide. The pressure drop on a clean element is 0, 5 ati, after driving 1.0 ati. Then the filter is filled to the level of a partition with a 5% solution of nitric acid heated to 60 ° C, in which the elements are kept for 4 hours with simultaneous sparging with compressed air. After this, shock regeneration is carried out in a filter in a nitric acid solution, in which hydroxides are removed from the surface of the filter elements. Then the solution is drained from the filter, filled with

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With hot water and for 2–3 m, the decomposition of the stitching material will proceed to bubbling for better washing, accompanied by the release of cells from JINOj. At the end of the process, a blown line of gaseous products is produced and heated to decomposition with a characteristic hall, 90 ° C air with a flow rate of 9 nm / h is fed to the filter (the specimen is visually inspected by filtration).

These elements are marked by the presence in their Zazo I n them the consumption of 10 -), Air is pinched in pax of unclaimed particles.

When drying low-grade (t

15. minutes, after which the filter 50 C) with air supplied to the filter by the gas field is water and produces a shock JO for 15 minutes, its consumption is regenerated in the presence of water. By. melts twice.

At its end, the pressure drop is measured. The proposed method of NIN regeneration. in the filter, the value of which makes it possible to achieve practically equal to 0.15 atm, which corresponds to the cleaning of the filter elements to its original value. A visually-controlled ion-exchange filter and a pre-inspection of zlemeits showed a half-time increase in filtering removal of all particles from their backs and a decrease in the hydraulic resistance. 2.25 nm of laziness of filter was spent on drying. This will reduce air consumption.

Claims (4)

PRI MER 2. -When Implementing. 20 and the amount of waste, as well as with the other method of waste -; Parameterize the energy and operating pat-m drying to a filter, cleaned from regeneration costs, hydroxide contaminants, are supplied heated to 90 ° C of air with a flow rate of 18 and 18 (specific flow rate 36). , within 9 min. Quality of regeneration. The method of regeneration of filtering remains, however, at the same time, the alluvial filter elements, including 2.7 nm of air, are consumed. Their treatment with an aqueous solution Example 3. The method carried out a chemical reagent that dissolves when drying ionites heated to 90 C 30 particles of contaminants, shock-regenerated by air, which is supplied with a flow of radio in this solution, npoNttiBKy-7, .5 HMV4 (specific consumption 15 nm / cm) before and emptying the filter, about t l-and - in 18 minutes. In this mode, 35% of the filtering capacity of the elementary air (2.25 nm) is observed for the purpose of high-quality regeneration, increasing the degree of recovery with a minimum amount of spent air, however, during the regeneration of the alluvium ionite and drying, the filter increases. emptying the filter from 5 to 18 years; drying the filtering filters and measuring them 4. The method of implementation is carried out with air heated to a temperature at the supplied air temperature not higher than 90 ° C, after which x is above and below 90 ° C. When passing the filter is filled with water and additionally through 3. ionite air filter. but the shock regeneration is carried out at a temperature of 100 ° C. Editor L. Kurasova Compiled by V. Vilinska Tehred M. Khodanich. Proofreader V. But ha Order 2490 Circulation 416 Subscription VNIIPI USSR State Committee for inventions and discoveries 113Q35, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 12 15 16 21