SK17832000A3 - Method of counterflow recovering ion exchangers - 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 a method of countercurrent ion exchange regeneration in "UPCORE" filtration processes, comprising a phase of compressing the ion exchanger layer with a bottom-up flow of liquid, a regeneration phase, gravitational settling and ion exchanger elution from the regeneration solution residues.

BACKGROUND OF THE INVENTION

A method for countercurrent regeneration of spent ion exchange resins is known, which consists of treatment with regeneration solution and top-down release described in FR 2 058 817.

The disadvantage of this process is the low efficiency of the regeneration process, which is caused by the considerable consumption of regeneration solutions and the need for water for its own consumption, as well as the longer time required for the regeneration of the resin.

Also known is a method of regenerating ion exchangers in UPCORE-type filtration processes, which is carried out in a filtering device containing an ion exchange resin, i.e., an ion exchange resin. an ion exchanger, and a chemically inert material, e.g. inert (see "The UPCORE ™ System, Engineering Handbook, May 1995, A1 page 5.6, B2 page 21)".

The method consists in performing a piston stroke operation after the filtration cycle and compressing the ion exchanger layer with an ascending jet of water, after which the regeneration solution is fed upwards to allow the ion exchanger layer to be compressed, and then the restoration of the regeneration residue is effected. The solution of the ion exchanger layer is allowed to settle under gravity and a water wash is performed in a direction consistent with the flow direction of the treated water in the working cycle. This ensures a degree of compression of the ion exchange layer in the range of 90% to 92%, for which a stream of water at a linear speed of up to 50 m / h for at least 3 to 5 minutes must be supplied, and at a flow rate of up to 20 m / h to keep the resin layer compressed.

The main disadvantages of this method are as follows;

- optimal regeneration of the resin cannot be achieved due to incomplete compression of the layer (up to 10% of the volume of the ion exchange layer at the bottom of the device remains uncompressed),

- considerable consumption of water to compress the layer and wash it, especially in the case of a high concentration of suspended matter in the treated water.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a process for the regeneration of ion exchange resins in UPCORE processes which would allow more efficient removal of impurities from the system, including those adsorbed on ion exchange resin granules, as well as shortening the regeneration time and volume of demineralized water consumed.

It has been envisaged that the particle regeneration methods can be greatly enhanced by subjecting the particles to a subsequent pressure and release action in order to micropulse on the surface of the ion exchange granules. Therefore, according to the present invention, the ion exchange layer is in the regene phase; a target subjected to at least two impulses, the mode of which has been chosen so that the ion exchanger layer is first compressed by two upstream waves and that the ion exchanger granule surface is subjected to an increased pressure, and then impurities adsorbed on the granule surface are subjected to after the pressure wave '. The degree of 'pressure wave release' must be selected in such a way that the compression layer is not released when the dirt is completely settled.

As a result of the interaction of the opposing wines, so-called " A “standing wave” that draws in its center particles placed on the edges of the layer and also increases the degree of compression of the ion exchange granules. As shown by the experiments carried out, the ion exchange layer is able to remain in the compressed state for up to 5 minutes without the aid of a liquid stream.

In carrying out the experiments, possible and optimal process parameters were found and substantial improvements in ion exchange resin regeneration results compared to UPCORE technology were confirmed.

SUMMARY OF THE INVENTION

It has been found that the above-mentioned deficiencies are largely overcome by a method of countercurrent ion exchange regeneration in "UPCORE" filtration processes comprising a phase of compressing the ion exchanger layer with a downstream liquid flow, regeneration, gravitational settling and that the compression method is performed in a pulse mode, wherein the water is supplied in at least two pulses, wherein the amplitude of the first pulse is not less than the height of the free zone above the ion exchange layer at the end of the duty cycle; which occurs after the pass of the previous pulse and the time between pulses does not exceed the time required for the reflected wave of the previous pulse to pass through the ion exchange layer.

The method according to the invention is preferably carried out in such a way that the first pulse lasts 0.1 to 60 seconds.

The method according to the invention is preferably further carried out in such a way that subsequent pulses are generated at intervals between pulses from 0.1 to 300 seconds.

The pulse amplitude is given by the interaction of the pulse duration and the overpressure value. During the pulse, the pressure is generally at least 0.01 MPa. The upper limit is given by the design of the device. The particular choice of parameters depends on the characteristics of the equipment used, the type of ion exchanger and the viscosity of the liquid to be treated.

The pulses are generally generated by hydraulic pressure, although they can also be generated pneumatically, mechanically or otherwise, or by a combination of the above methods.

The process of the invention can be used in virtually any type of ion exchange resin when there is an inert material layer at the top, although better results are obtained when used with ion exchange resins such as DOWEX ™ resins such as the weakly acidic cation exchanger MAC-3 , strongly acid cations Marathon C, UPCORE Mono C-600, Monosphere 650 C, weakly acidic anion exchangers Marathon WBA, UPCORE Mono WB-500, strongly acidic anion exchangers Marathon A, Marathon 11, Marathon A2, UPCORE Mono A-625, UPCORE Mono A -500, Monosphere 550 A and others. It is recommended to use DOWEX UPCORE IF-62 as an inert material for optimum results.

The process for treating the ion exchangers according to the invention can also be used at other stages of the process. In particular, when carrying out the experiments, it has been found that the introduction of the sulfuric acid regeneration solution according to the invention can reduce the probability or even completely eliminate the formation of a gradual cation of gypsum.

Thanks to the method according to the invention, it is also possible to achieve that the resin layer is hardened to virtually 100% and that the water consumption for the operation after compression of the layer is reduced by at least half. Other advantages are that there is no need. the installation of an additional power pump, which is used to create a piston buoyancy and to compress the resin layer, and in the case of a common current wiring diagram in a countercurrent wiring diagram, there is no need to change piping and rebuild the equipment.

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Overview of the figures in the drawing

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be explained in more detail with reference to the drawings of an overall process and apparatus diagram, in which FIG. 1 to 4 show the entire operating cycle, and FIG. 1 shows the filtration phase, FIG. 2 shows the compression phase of the ion-exchange layer, the supply of the reactants and their displacement, FIG. 3 shows the deposition phase and FIG. 4 stage of washing the system.

In FIG. 1 to 4, the upper distribution member 1, the floating inert layer 2, the free space 3, the ion exchange layer 4 and the lower distribution member 5 are shown.

DETAILED DESCRIPTION OF THE INVENTION

The regeneration process is carried out in a water treatment filter in which an ion exchange resin and an inert material are placed in the filter, and then the cycle phases described below take place.

During the operating cycle shown in FIG. 1, the treated water flows into the filter from above and passes sequentially through the upper distribution member 1, the floating inert layer 2, the free space 3, the ion exchanger layer 4 and the lower distribution member 5 and then leaves the filter. During the operating cycle, the ion-exchange layer 4 is pressed against the lower distribution member 5 and the free space zone 3 is located in the apparatus above the ion-exchange layer 4.

After the exchange capacity of the ion exchange layer 4 has been exhausted, i. upon completion of the operating part of the cycle, the feed of the treated liquid to the ion exchange filter is stopped in the top-down direction and the regeneration part of the cycle is started (Fig. 2). In carrying out the ion exchanger regeneration (FIG. 2), a water jet comes from below upwards in a pulsed mode, the water jet lifting the entire ion exchanger layer 4 without stirring inside the ion exchanger layer 4 and pressing it onto the inert layer 2 or the upper distribution member i, at the same time it ensures the removal of impurities that have accumulated during the working part of the cycle from the ion exchange layer 4 and the filter. Thereafter, a stream of regeneration solution is fed from the bottom upwards, passing through the ion exchanger layer 4, carrying out its chemical regeneration, leaving the ion exchanger layer 4 in a compressed state. The regeneration solution can be supplied in a continuous or pulsed mode. Upon completion of the regeneration, the operation of displacing the remainder of the regeneration solution in the compressed ion-exchange layer 4 is carried out by conducting a stream of water in a top-down direction. The water supply can be carried out in continuous or pulse mode.

In the next phase of the cycle, a settling operation is performed (Fig. 3), shutting off the supply of process currents to the ion exchange filter device, so that only the gravitational force is laminarly applied to the ion exchange layer 4, i.e. evenly without agitation within the layer, and this settles on the lower distribution body 5. The free space zone 3 moves from the lower distribution body 5 to the upper distribution body 1 or the inert layer 2.

The last operation of the cycle is a washing (Fig. 4), which is carried out in the same direction as the water treatment in the working cycle, i. top to bottom.

For carrying out the process according to the invention, it is particularly advantageous to use ion exchangers of the DOWEX UPCORE type, for example the strongly acidic cation Mono C 600, the strongly basic anion Mono WB-500 and others. This is related to the fact that resins of these types have a homogeneous granulometric composition and improved physical mechanical characteristics, which improves the hydrodynamic parameters of the regeneration process of the resins.

For inert materials, better results are obtained by using an inert. DOWEX UPCORE IF-62

The industrial tests were carried out on a filter apparatus with a filter container volume * of 0.5 m ³ , where 0.45 m ³ of a DOWEX UPCORE Mono C 600 type ion exchange resin based on a styrene-divinylbenzene matrix in sodium form with a total ion exchange capacity of at least 2 were inserted. 2 roll / l 0.02 m ^{3 of} inert material DOWEX UPCORE IF-62.

After the exchange capacity of the ion exchange layer was exhausted (end of the working part of the cycle), the supply of treated water to the ion exchange filter was interrupted in a top-down direction and regeneration was performed. To this end, a portion of the treated water was fed under a layer of ion exchange resin in a bottom-up direction over a wide time and pressure range. At the end of the first pulse, a second pulse was created after the set time elapsed, changing its parameters in the different test series and the third pulse in a series of trials. The degree of compression was checked visually.

Then, the water supply was stopped and a regeneration solution based on sodium chloride or sulfuric acid was supplied according to the instructions enclosed with the supplied resin.

After the chemical regeneration of the ion exchange layer was complete, the remnants of the regeneration solution were displaced by a stream of demineralized water added in a bottom-up direction. Then, the supply of demineralized water was stopped, causing the ion exchange resin layer to settle under gravity. The deposited layer of the ion exchange resin was washed with a stream of treated water in a top-down direction, simultaneously compressing it.

This completes the regenerative part of the cycle.

The results obtained in the tests of the effect of process parameters on water purification efficiency are shown in Table 1.

The experiments listed in Table 1 were performed on a standard chemical water purification plant that had previously used UPCORE technology and had a mean output of 150 m ³ / h. and the volume of water treated per filter cycle of 1000 m ³ . After the regeneration system has been switched to the method according to the invention, it has been shown that it is possible to achieve an extended filtration cycle without reducing the quality of the treated water.

The results are shown in Table 2.

As can be seen from the examples, the process of the present invention allows for more thorough removal of impurities from the ion exchange resin layer corresponding to the higher efficiency of the regeneration process thereof. The recovery time is reduced by an average of 5 to 7% depending on the x-character

ion exchanger, its durability and nature of impurities. Water losses for own consumption are reduced by 10 to 12%.

Industrial usability

The method of countercurrent regeneration of ion exchangers according to the invention can be used in power engineering, metallurgy, chemical industry and other industries using demineralized or softened water in technological processes.

Table 1

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

Process parameter / mode no. 1 2 3 4 5 6 fluid Water Water Water Water Water 20% aqueous solution sugar Number of pulses 2 2 2 3 3 2 Duration of 1st pulse [sec] 60 30 9 2 0.1 60 Interval between 1st pulse and 2. pulse [sec] 4 0.1 10 5 2 300 Duration of 2nd pulse [sec] 0.1 5 2400 2 0.1 1200 Interval between pulse 2 and 3 pulse [sec] 5 2 Duration of 3rd pulse [sec] 2 900 Degree of layer compression 99.9 99.9 99.9 99.9 95.2 96.1 Specific water ratio for layer compression [m ³ / m ² ] 6.0 3.0 0.9 2.8 0.01 6.0

Table 2

Water purification efficiency under industrial conditions using the prior art method and the method of the present invention

indicator technology UPCORE UPCORE technology modified according to the invention Time to press ion exchange layers [sec] 180 0.1 9 60 180 Degree of compression of the ion exchange layer [m ³ / m ² ] 90.1 95.2 99.9 99.9 99.9 Specific water ratio for ion exchange layer compression [m ³ / m ² ] 4.5 0.01 0.9 6.0 18.0 Linear current velocity regeneration solution for ion exchanger reactivation resin and its retention in compressed state [m / hj 12 to 15 1 to 7 1 to 7 1 to 7 1 to 7 Volume of purified water up to 100 pg / l sodium, [m ³ ] 1000 1030 1080 1080 1080

Claims (3)

A method for countercurrent ion exchange regeneration in "UPCORE" filtration processes, comprising a phase of compressing the ion exchanger layer with a bottom-up flow of liquid, a regeneration phase, gravitational settling and elution of ion exchanger from regeneration solution residues, characterized in that mode, wherein the water is supplied in at least two pulses, wherein the amplitude of the first pulse is not less than the height of the free zone (3) above the ion exchange layer (4) at the end of the duty cycle and after passing the previous pulse and the time between pulses does not exceed the time required for the reflected wave of the previous pulse to pass through the ion exchange layer (4). Method according to claim 1, characterized in that the first pulse lasts 0.1 to 60 seconds. A method according to claim 1, characterized in that the following pulses are generated at time intervals between pulses from 0.1 to 300 seconds. Inlet of treated water eluate to waste Treated water Fig. 1 Figure 2. water for washing waste / recycling Fig. 3 Fig. 4