EA002503B1 - Process for countercurrent regeneration of ionites - Google Patents

Abstract

1. A method of regeneration of ionites in "UPCORE" -type filtration processes including a stage in which ionite bed is held down by upward directed liquid medium current, a regeneration stage, gravitation settlement and washing out ionites from residues of regeneration solution, characterirized in that said holding-down process is accomplished in pulse mode, where water is supplied at least between two pulses, wherein the amplitude of the first one is selected as being not lower than the height of free space zone over ionite bed at the end of working cycle and amplitude of the next pulse is not inferior to the amplitude of reflected wave arising after decay of preceding pulse, inter- pulse period does not exceed time required for passage of reflected wave from preceding pulse through ionite bed. 2. The method of claim 1, characterized in that the duration of the first impulse is from 0.1 to 60 sec. 3. The method of claim 1, characterized in that subsequent pulses are sent with inter-pulse period from 0.1 to 300 sec.

Description

The invention relates to methods of purification of natural and waste waters, as well as other liquid solutions using ion exchange filters, and in particular to methods of regeneration of ion exchange resins (IC), and can be used in power engineering, metallurgy, chemical and other industries that use desalted or softened water in technological processes.

There is a method of countercurrent regeneration of spent ICs, including the processing of the regeneration solution, and loosening from the bottom up, and washing with water from top to bottom (US Pat. Of the Russian Federation No. 2058817, 1995, class C 02P 1/42).

The disadvantage of this method is the low efficiency of the regeneration process due to the high consumption of regeneration solutions and wastewater, as well as the increased time of the regeneration process of the resin.

The prototype of the claimed method is a method for the regeneration of ion exchangers in the filtration processes of the type IRSOKE carried out in filtration plant containing an ion exchange resin (ion exchanger) and is chemically inert under the conditions of the ongoing process material (inert) (Tye IRSOKE 8uz1st, Epdtssttd Napyyook, Ttaystatk about £ Tye Ωο \ ν Systilea Sotrupa, Mau 1995, A1 Radsz 5, 6, B2 Rads 21).

The method consists in the fact that at the end of the filtration filtration cycle, the piston-shaped lifting and clamping of the ion exchanger layer are carried out by an ascending flow of water, after which a regenerating solution (regenerant) is fed in the bottom-up direction with a flow rate ensuring that the ion exchanger layer remains in the clamped state, then displace residues of the regenerant by the upward flow of water without decompression of the clamped layer of ion exchanger, after which they allow the resin layer to settle under the influence of gravity and carry out washing with water in the direction coinciding present with the direction of flow of treated water in the working cycle. This ensures the degree of clamping of the ion exchanger layer in the range from 90 to 92%, which requires a flow of water with a linear speed of up to 50 m / h for at least 3-5 minutes, and for the regeneration of the resin a regenerant is fed for up to 1 hour with a linear flow rates up to 20 m / h to keep the resin layer in the clamped state.

The main disadvantages of the prototype are the impossibility of the implementation of the optimal resin regeneration due to incomplete clamping of the layer (up to 10% of the volume of the resin layer in the lower part of the apparatus remains in an unstressed state);

significant water consumption for the layer clamping and its washing, especially in the case of a high concentration of suspended matter in the treated water.

The problem solved by the authors was the development of a method for the regeneration of ion exchange resins in processes such as IRSAKE, which allows for more efficient removal of impurities from the system, including ICs adsorbed on granules, as well as reducing the regeneration time and reducing the volume of demineralized water used.

It has been suggested that particle regeneration processes can be dramatically enhanced by subjecting the particles successively to increased pressure and vacuum to create micropulsations on the surface of the ion exchanger grains. To solve the problem, the authors proposed to expose the layer of ion exchanger during the regeneration process to at least two successive pulses, the mode of which was chosen so that the ion exchanger layer was first clamped by two oppositely directed waves, and the surface of its grains was subjected to increased pressure, and then passage of the increased pressure wave sorbed on the grains of the particles were exposed to post-wave rarefaction. In this case, the degree of post-wave rarefaction should be selected in such a way that, with the fullest decantation of the contaminants, the loosening of the clamped layer is excluded.

As a result of the interaction of oppositely directed waves, in the zone of the clamped ion exchanger, a so-called standing wave is formed, which tightens the particles to its center, located on the periphery of the layer and thereby increasing the degree of clamping of the ion exchanger granules. As shown by the experiments, as a result of this treatment, the ion exchanger layer is able to remain in the clamped state for up to 5 minutes without supporting the flow of liquid.

In the course of the experiments, possible and optimal parameters of the process were established and a significant improvement in the results of the regeneration of ion-exchange resins was confirmed in comparison with the technology of PURCO.

In particular, it was found that the problem is solved when using the proposed method in the case that at the stage of squeezing the ion-exchange resin, the ionite layer is affected by applying at least two pulses of water, and the amplitude of the first pulse is at least the height of the free zone space above the ion exchanger at the end of the work cycle, and the amplitude of each subsequent pulse is not less than the amplitude of the reflected wave that occurs after the previous pulse, and the time between the pulse and not more than the time required for passage of the reflected wave from the preceding pulse through the resin bed.

The duration of the first pulse in industrial installations is from 0.1 to 60 s, and the time between pulses is from 0.1 to 300 s.

The pulse amplitude is set by a combination of the pulse duration and the overpressure value. As a rule, the pressure when creating a pulse is at least 0.01 MPa. The upper limit is determined by the installation design. The specific choice of parameters is carried out depending on the characteristics of the installation used, the type of ion exchanger and the viscosity of the liquid being cleaned.

Impulses are created, as a rule, by creating hydraulic pressure, although it is possible that they are formed by pneumatic, mechanical or other, including complex effects.

The inventive method can be used on virtually any type of ion exchange resins when placed in the upper layer of inert material, however, the best results are achieved when using as resins such маркиνΌΘ resins as weakly acidic cation exchanger MAS-3, strongly acidic cation exchangers Matashop C, ICROVE Mopo S- 600, Mopokrjete 650 C, weak-basic anionites Matashoi \ UVL. IRSOVE Mopo νΒ-500, strong base anion exchangers MataShop A, MataShop 11, MagaShop A2, IRSOVE Mopo A-625, IRSOVE Mopo A-500, Mopokriete 550 A and others. For optimal results, it is recommended to use IO ^ EX IRSOVE ΙΕ-62 as an inert material.

The inventive method of influence on ion exchangers can be implemented at other stages of the process. In particular, in the course of the experiments it was found that when a regenerating sulfuric acid solution is applied in the inventive mode, it is possible to reduce the likelihood or eliminate the occurrence of the cation exchanger gypsum in general.

Through the use of the proposed method, it is possible to achieve that the resin layer is compacted by almost 100%, and the water consumption for the operation to clamp the layer is reduced by at least 2 times. Additional advantages are the fact that there is no need to install an additional pump of greater power used for piston-like lifting and clamping of the resin layer, and in the case of reconstructing a flow-through circuit into a countercurrent, replacement of pipelines and equipment re-coupling is excluded.

The regeneration process is as follows. Ion exchange resin and inert material are loaded into the filtration plant for water treatment.

The general scheme of the process is shown in FIG. 14, where in FIG. 1 shows the filtering duty cycle, FIG. 2 - the stage of clamping of the ion exchanger layer, the supply of reagents and their displacement, in FIG. 3 stage of deposition, in FIG. 4-stage washing system.

At the same time on the drawings introduced the following notation:

- the upper switchgear (ASU);

- a layer of floating inert;

- free space;

- Ionite layer;

- lower distribution device (LRU).

During the working cycle (Fig. 1), the purified water enters the filter from above, passing successively through the ASU 1, inert 2, free space 3, ion exchanger 4, HPA 5, and then is removed from the filter. Upon depletion of the exchange capacity of the resin layer (the end of the operating cycle), the supply of the treated liquid to the ion-exchange filter is stopped from top to bottom and the regeneration process is started (Fig. 2). In this case, the layer of ion exchanger is pressed to the NRU 5, and the zone of free space 3 is in the apparatus above the layer of ion exchanger 4.

When carrying out the process of regeneration of the ion exchanger (Fig. 2) in a downward-upward direction, a stream of water is fed in a pulsed mode, which raises the entire layer of ion exchanger 4 without intralayer mixing, pressing it to the inert 2 or ASU 1, simultaneously ensuring removal of the ion exchanger and filter suspensions accumulated during the working cycle.

Then in the direction of the bottom-up serves a stream of regenerating solution, which, passing through the layer of ion exchanger 4, carries out its chemical regeneration, keeping the layer of ion exchanger 4 in the clamped state. The supply of the regenerating solution is carried out in continuous or pulsed mode.

Upon completion of the regeneration, an operation is carried out to displace residues of the regenerating solution from the sandwiched ion exchanger layer, feeding a stream of water in the bottom-up direction. Water flow to the displacement can also be fed in a continuous or pulsed mode.

At the next stage, the deposition operation is carried out (Fig. 3), for which the flow of process streams to the ion exchange apparatus is turned off, and the ion exchanger 4 under the action of gravity laminar (uniformly, without interlayer mixing) settles on the LRU 5. At the same time, the free space zone 3 migrates from NRU 5 to I LIE 1 or inert 2.

The final operation is flushing (FIG. 4), performed in the same direction as the treatment of the source water in the operating cycle.

To implement the proposed method, it is preferable to use ICs of the IO ^ EX IRSOVE brand, for example, Mopo C 600 strongly acidic cation exchanger, Mopo A625 strongly basic anion exchanger, Mopo \ HC-500 weakly basic anion exchanger and others. This is due to the fact that the resins of these grades have a uniform particle size distribution and high physicomechanical characteristics, which improves the hydrodynamic parameters of the resin regeneration process. As an inert material, the best results are achieved with the use of inert EOHUHEH IRSOKE GE-62.

Industrial tests were carried out on the basis of a filtration unit with a capacity of 0.5 m ³ , where 0.45 m ^{3 of} resin EOHUYH IRSOK Mopo C 600 was loaded, based on the sodium styrene vinyl benzene matrix with a total resin exchange capacity of at least 2.2 g-eq ./l and 0.02 m ^{3 of} inert material 1ЖЖЕ.Х ИРСОКЕ ГЕ-62.

After depletion of the exchange capacity of the resin layer (completion of the working cycle), the supply of treated water to the ion-exchange filter was stopped in the top-down direction and proceeded to the regeneration process. For this, part of the purified water was supplied under the resin layer in the bottom-up direction with a wide range of time and pressure. After a fixed time after the cessation of the supply of the first impulse, a second impulse was applied (by varying its parameters in various test series) and in a series of experiments the third impulse.

Then the supply of water was stopped and a regenerating solution based on sodium chloride or sulfuric acid was supplied in accordance with the instructions attached to the resin upon delivery.

Upon completion of the chemical regeneration of the layer, the remnants of the regenerating solution were displaced by a stream of demineralized water supplied in the bottom-up direction. Next, the water supply was stopped, as a result of which gravitational sedimentation of the resin layer occurred. The settled resin layer was washed with a stream of treated water in the top-down direction, simultaneously clamping it, after which the next working cycle of water purification was performed.

The results of the tests, reflecting the influence of process parameters on the efficiency of water treatment, are given in Table. one.

Table 1

Impact of regeneration parameters on the effectiveness of water purification and aqueous solutions

Liquid Process parameter Number of imp. Duration 1st imp., with Time between 1 and 2 imp., S Duration 2nd imp., With Time between 2 and 3 imp. With Duration 3rd imp., With The degree of clamping layer Ud. water consumption for layer clamping, m ³ / m ² Water 2 60 four 0.1 99.9 6.0 Water 2 thirty 0.1 five 99.9 3.0 Water 2 9 ten 2400 99.9 0.9 Water 3 2 five 2 five 2 99.9 2.8 Water 3 0.1 2 0.1 2 900 95.2 0.01 20% rr sugar 2 60 300 1200 96.1 6.0

Experiments carried out on a typical chemical water treatment plant that previously used iRSOKE technology (with an average capacity of 150 m ³ / h and a filter cycle volume of 12000 m ³ ), when replacing the regeneration system with the claimed modified one, showed the possibility of achieving a higher filter cycle without reducing the quality of the treated water. (The results of the experiments are given in table. 2.)

table 2

The efficiency of water purification in industrial conditions with the use of traditional and the proposed technology

Indicator Technology IRSOKE Modified technology IRSOKE The time required to seal the layer (T), with 180 0.1 9 60 180 The degree of clamping layer% 90.1 95.2 99.9 99.9 99.9 Specific water consumption for layer clamping, m (i.e., m ³ / m ² ) 4.5 0.01 0.9 6.0 18.0 Linear flow rate of reagents for reactivation of the resin and maintaining the resin in the clamped state, m / h 12-15 1-7 1-7 1-7 1-7 The volume of purified water to a degree of overshoot of sodium 100 µg / l, m ³ 1000 1030 1080 1080 1080

the nature of the IC, the life of the ion exchanger and the nature of the pollution. The cost of water for own needs is reduced by 10-12%.

Claims (3)

CLAIM 1. A method for the regeneration of ion exchangers in filtration processes of the IRSOKE type, including The time spent on regeneration is reduced by an average of 5-7%, depending on the stage of clamping of the ion exchanger layer by the liquid flow directed from the bottom up, the stage of regeneration, gravitational deposition and washing of ion exchanger from the remnants of the regenerating solution, characterized in that the process the clamping is carried out in a pulsed mode, supplying water with at least two pulses, and the amplitude of the first pulse is chosen so that the height of the ion exchanger is not less than the height of the free space zone above the layer and nit at the completion of the operating cycle, and the amplitude of the subsequent pulse amplitude at least otraObrabatyvaemaya water eluate drains Purified Water Reagents Water FIG. 1 FIG. 2 wave, arising after the passage of the previous pulse, and the time between pulses is not more than the time required for the reflected wave from the previous pulse to pass through the ion exchanger layer. 2. The method according to claim 1, characterized in that the first pulse is fed with a duration of from 0.1 to 60 s. 3. The method according to claim 1, characterized in that the subsequent pulses are served with an interval of time between pulses from 0.1 to 300 s.