BG104966A - Method for countercurrent ionite regeneration - Google Patents

Abstract

The method is used in the power industry, metallurgy and in industry for the preparation of soft or demineralized water for technological processes. By it natural and waste waters and other solutions are treated by means of ion-exchange filters and in particular using the methods for the regeneration of ion-exchange resins. The ionite regeneration method is of the UPCORE type. The stage of the ionite layer compaction is made by a flow of liquid medium, moving upwards from the bottom. The compaction process is made by pulsations, the water being moved to at least two pulsations, where the amplitude of the first pulsation is not less than the height of the free edge over the ionite layer at the end of the operating cycle. The amplitude of the next pulsation is no less than the amplitude of the reflected wave, appearing after the passing of the previous pulsation, and the time between two pulsations does not exceed the time required for passing of the reflected wave of the previous pulsation across the ionite layer. By the method, the contamination of the ionite layer are eliminated much more easier, and, therefore, there is higher efficiency of the regeneration process. The regeneration time is reduced by about 5-7 %, depending on the ionite type and its operational life. The consumed inplant water is reduced by 10-12 %. 3 claims, 4 figures

Description

METHOD FOR IONITIUM CURRENT REGENERATION

The invention relates to the methods of purification of natural and waste water as well as to liquid solutions by means of ion-exchange filters, and in particular relates to methods for the regeneration of ion-exchange resins and can be used in energy, metallurgy, chemical and other branches of an industry where soft and desalinated water is used for their technological needs.

The method of countercurrent regeneration of depleted ion exchange resins is known, including treatment with a regeneration solution and passing it from the bottom up, and the washing with water from the top down (Patent RF No. 2058817,1995, СО2Р 1/42).

The disadvantage of this method is the low efficiency of the regeneration Q process, due to the considerable consumption of regenerative solution and water for own use, as well as the increased time for regeneration.

The proposed prototype method is a method for ionic regeneration during the UPCORE process, which is carried out in a filter column containing an ion exchange resin (ionite) and an inert material (inert) that is chemically inert under the conditions of the process performed (The UPCORE System. Enginering Handbook, Trademark of the Dow Chemical Company, May 1995, Al page 5,6, B2 page 21)

The method is based on the fact that upon completion of the filtration cycle, piston-type lifting and compacting operations of the ionic layer by water flow are performed, and then the regeneration solution (regenerant) is fed from below upward at such a speed as to keep the ionic layer compacted. state, after which the residual regenerant is forced out by water flow without stirring the compacted F ionite layer, after which the resin layer is allowed to gravitate and then the rinsing is carried out with water in a direction coinciding with the direction of water during the production cycle. In this case, the degree of compression of the ionic layer is in the range of 90% to 92%, to achieve which it is necessary to supply water at a linear speed of up to 50m / h for at least 3 to 5 minutes and for the regeneration of the resin. delivers regenerant for 1 hour at a linear speed of up to 20m / h to keep the resin layer compact.

The main disadvantages of this prototype method are:

• Inability to obtain optimal resin regeneration due to incomplete compacting (up to 10% of the resin volume in the bottom of the filter remains in the non-compacted state) • Considerable consumption of compacting and washing water, especially in the case of high concentrations of dissolved water substances in treated water.

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The problem for the authors of the method to solve was the development of a method for the regeneration of ion exchange resins in the UPCORE process, which allows more efficient removal of impurities from the system, including those adsorbed on the resin granules, as well as reducing the regeneration time and the amount of demineralized water for own needs.

It has been suggested that the regeneration of the resin grains can be abruptly impaired by successively subjecting them to the action of increased pressure and expanded pressure to create micropulsations on the surface of the ionic grains. To address this problem, the authors suggested that the ionic layer be subjected to at least two consecutive pulses regenerated during regeneration, the force of which was chosen such that the ionic layer was first compacted by two counter waves and the surface of the grain resin was exposed. and then after passing this increased pressure, the particles resorbed on the grain resin are subjected to a secondary wave pressure. In this case, the degree of this secondary pressure must be chosen so that, at maximum separation of impurities, no compaction of the layer is obtained.

As a result of the interaction of the counter waves, a so-called standing wave is produced in the zone of compacted ionite, which attracts the particles from the periphery to the center, and thus increases the degree of compacting of the ionic grains. As shown by the experiments performed, in such a treatment the ionic layer can remain in a compacted state for up to 5 minutes without a support stream.

In the process of the experiments, the possible and optimal parameters of the process were determined and the main improvements in the results of ion exchange resin regeneration were confirmed as compared to UPCORE technology.

In particular, it was determined that said problem be solved by applying the proposed patent method in the case where the resin is compacted and at least two pulses are applied to the ionic layer at which the amplitude of the first pulse is not less than the height of the freeboard at the end of the duty cycle, and the amplitude of each subsequent pulse is not less than the amplitude of the reflected wave obtained after the passage of the previous pulse and the time between the two pulses is not less than the time required to pass the reflected wave from the previous pulse in ionite layer.

The duration of the first pulse in industrial installations lasts from

0.1 to 60 seconds, and the time between two pulses - 0.1 to 300 seconds.

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The pulse amplitude is determined by the bm < > > of the * pulse * and the pressure value. As a rule, it is assumed that when pulse pressure is at least 0.01 MPa.

The upper limit is determined by the design of the filter. The specific choice of parameters is made depending on the specific characteristics of the installation, the type of resin and the viscosity of the liquid to be treated.

As a rule, ripples are made by creating hydraulic pressure, but can also be caused by pneumatic, mechanical or other action, including the combination of the above.

The patented method can be used with virtually any type of ion exchange resin, but the best results are achieved with the use of DOWEX (Trademark of The DOW Chemical Company): MAC 3 - as a slightly acidic cation exchanger, DOWEX Marathon C (trademark of The DOW Chemical Company), DOWEX UPCORE Mono (trademark of The DOW Chemical Company) C-600, as highly acidic cationite, DOWEX Monosphere (trademark of The DOW Chemical Company) 650 C, as highly acidic cationite, DOWEX Marathon WBA, UPCORE Mono WB-500, Marathon A, Marathon 11, Marathon A2, UPCORE Mono A-625, UPCORE Mono A-500, Monosphere 550 A as a very basic anionitis and others.

For optimum results, it is recommended that DOWEX UPCORE IF-62 be used as aggregate.

The proposed patent method can also be applied in other stages of the process. In particular, it has been determined experimentally that when using the method in sulfuric acid regeneration it is possible to reduce or completely avoid gypsum plating.

Due to the method 100% compaction of the layer is possible and the amount of water required for compacting is reduced at least twice. An additional advantage of this is the fact that there is no need to install an additional powerful pump for lifting the layer, and in the case of reconstruction of a flow-through installation in a counter-current, it is not necessary to change pipelines and interconnect the filters.

The regeneration is carried out as follows:

The regeneration flow diagrams are shown in FIG. 1 to 4, where figure 1 shows the duty cycle, figure 2 shows the compacting of the ionite layer, the feeding of the reagents and their ejection, figure 3 shows the lowering of the layer and figure 4 the washing process.

The following numerals are used in the drawings:

1- Upper Distributor (GRU)

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2- Floating aggregate '

3- Free board

4- Ionite layer

5- Bottom switchgear (DRU)

During the duty cycle (FIG. 1), the raw water enters the filter from above and successively passes through GRU 1, inert material 2, freeboard 3, ionite layer 4, DRU 5 and leaves the filter below. When the resin is depleted (end of the duty cycle), the supply of water to the ion exchange filter from above is interrupted and the regeneration process begins. In this case, the ionic layer is pressed to the DRU 5 and the free board is above the ionic layer.

During the regeneration process (Fig. 2), a flow of lower-up ripple water is supplied, which raises the entire ionic layer 4 without mixing the individual layers and compressing it to the inert material, while removing the suspended particles accumulated during the duty cycle. .

The regeneration solution is fed from the bottom up, and passing through the ionic layer 4, chemical regeneration of the ionite is carried out, keeping the layer in compacted state. The regeneration solution is fed in a constant flow or with ripples.

At the completion of the regeneration, the remaining regeneration solution is expelled from the compacted ionic layer with a stream of water directed downwards. This flow of water can be supplied in a constant flow or with ripples

The next step is the lowering of the layer (Fig. 3), during which the flow in the filter is stopped and the ionic layer is dropped downward in gravity laminarly (uniformly without stirring the layer) to

DRU 5. In this movement the freeboard migrates from DRU 5 to GRU 1 or to inert material 2.

The last step is the flushing (Figure 4). It is carried out in the same direction as in the work cycle - from top to bottom.

It is preferable to use DOWEX UPCORE MONO C-600 ion exchange resins as a highly acidic cation exchanger, DOWEX UPCORE MONO UV-500, as a weakly basic anionite, and the like for the implementation of the proposed patent method.

This is due to the fact that the resins with these brands have a homogeneous particle size distribution and high physical and mechanical characteristics that improve the hydrodynamic parameters of the resin regeneration process. Best results are obtained when DOWEX UPCORE IF-62 is used as aggregate.

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The tests were carried out with a 0.5 m3 filtration column in which 0.45 m3 of DOWEX UPCORE Mono C-600 type resin was loaded on the basis of a sodium styrene-divinylbenzene matrix with an exchange capacity of at least 2.2 g / l and 0, 02 m3 inert material DOWEX UPCORE IF-62.

After depletion of the exchange capacity of the resin (end of the duty cycle), the supply of raw water for top-down treatment is stopped and the regeneration cycle begins. To this end, a portion of the treated water was fed below the resin layer in a downward direction over a wide range of time and pressure. After a certain time after the first pulse was performed, a second pulse was performed (its parameters were changed in different series of tests) and in some of the experiments, a third pulse was performed. The degree of compacting in the experiments was monitored visually.

After compacting, the water supply was stopped and a regeneration solution based on sodium chloride or sulfuric acid was supplied, according to the instructions of the resin manufacturer.

After the chemical regeneration of the layer was completed, the remaining regeneration solution was forced out with a stream of demineralized water in the upward direction. After that, the water flow stopped and gravity started to descend. The lowered layer was flushed with treated water in a top-down direction, at the same time compacting the layer before the next duty cycle began.

The results obtained reflect the influence of process parameters on

j Table 1

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Influence of the parameters Ma regeneration on the purification efficiency of water and aqueous solutions

| Fluid Process parameters

Pulse count Duration At 1 pulse seconds Time Between 1 and 2 pulse seconds Time On the 2nd Pulse Seconds Time Between 2 and 3 your heart rate seconds Time for you heart rate seconds Degree of compacting % Specific water consumption for compacting m3 / m2 Water 2 60 4 0.1 99.9 6.0 Water 2 30 0.1 5 99.9 3.0 Water 2 9 10 2400 99.9 0.9 Water 3 2 5 2 5 2 99.9 2.8 Water 3 0.1 2 0.1 2 900 99.5 0.01 20% sugar solution 2 60 300 1200 96.1 6.0

The experiments were carried out on a standard UPCORE installation (average capacity 150 m3 / h and 1000 m3 of water produced between two regenerations), replacing the regeneration system with the proposed patent method, which allowed to show the possibility of increasing the filtration cycle without to deteriorate the quality of the treated water.

The results of the experiments are given in Table 2.

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Purification Effectivity in Industrial Equipment Using Standard and Patent Proposed Technology

Parameter UPCORE technology Modified UPCORE technology Time required to seal the layer (T), seconds 180 0.1 9 60 180 Degree of compaction of layer% 90.1 95.2 99.9 99.9 99.9 Specific water consumption for compacting the m3 / m2 layer 4.5 0.01 0.9 6.0 18.8 Linear flow rate of resin regeneration reagent and compacted m / h 12 to 15 1 TO 7 1 TO 7 1 TO 7 1 TO 7 The amount of water treated to jump to sodium 100 mg / l, in m3 1000 1030 1080 1080 1080

As can be seen from the examples, the use of the proposed patent method makes it possible to completely remove impurities from the ion exchange resin and, accordingly, to increase the efficiency of the process in its regeneration.

In this case, the regeneration time is reduced by an average of 5 to 7%, depending on the type of ionite, how long the nature of the impurities has been working.

The amount of water for own use is reduced by 10 to 12%.

Claims (3)

1. The standard UPCORE method for ionic regeneration, including top-down operation, bottom-up compacting with water flow, regeneration steps, gravity lowering and rinsing of residual regeneration solution, differs from the proposed patent method in that the compacting process is performed by pulsations giving water to at least two pulses, wherein the amplitude of the first pulse is not less than the height of the free board above the ionite after work, and the amplitude of the next pulse is not less than the amplitude so the reflected wave caused after the passage of the previous pulse and the time between two pulse does not exceed the time required for passage of the reflected wave from the preceding pulse in ionite layer. © 2. The method described in item 1 also differs from the fact that the duration of the first pulse is from 0.1 to 60 seconds. 3. The method of item 1 also differs in that the subsequent pulses are performed at intervals of time between two pulses from 0.1 to 300 seconds.