RU2680050C1 - Method of processing natural saltish water with obtaining solutions of complex mineral fertilizers and installation for its implementation (options) - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: group of inventions can be used in agriculture in the regions of irrigated agriculture for fertigation: irrigation and simultaneous application of mineral fertilizers in the form of solutions. Method and installation options for its implementation include the processing of source water in three successively located ion-exchange columns – two with cationite (C3, C1) and one (C2) with anion exchange resin in the form of agrochemically valuable components of the obtained complex mineral fertilizer. Solution from the exit of the second along the flow of the cation column (C1) is sent to the nanofiltration (NF) unit to obtain a concentrate and permeate. One part of the latter is sent to the anion exchange column (C2) to produce a solution of complex mineral fertilizer at its outlet, and the other to the desalination plant (DES) to obtain demineralized water at the same time as the fertilizer to prepare the fertigation solution. Salt concentrate after desalination, collected in reservoirs (R1), is used for regeneration of the cation exchanger in the column (C1), and regenerate of this column together with the salt containing the cationic component of the resulting fertilizer - for regeneration by the first column (C3). In the anion exchange column (C2), regeneration is carried out using a salt containing the anionic component of the resulting fertilizer. Installation options are different schemes for the preservation and reuse of the regenerating solution, displaced from the free volume of the columns. In one embodiment, a common reservoir (R1) is used for externally supplied and displaced regenerating solution, and in the other, two separate containers.

EFFECT: inventions prevent ingress of harmful components into the resulting mineral fertilizer, disruption of the desalination plant, as well as the formation of insoluble precipitates in columns and waste solutions; in addition, the concentrate after nanofiltration is additionally obtained by complex fertilizer.

27 cl, 9 dwg, 16 tbl, 6 ex

Description

The invention relates to agriculture, and in particular to a technology for producing solutions of mineral fertilizers intended for fertigation: irrigation and simultaneous application of fertilizers when cultivating crops mainly in irrigated areas with water deficit for irrigation, and more particularly, to a method for processing natural brackish water to produce solutions of complex mineral fertilizers and two installation options for its implementation.

The simplest approach to obtaining solutions of complex (containing two or more nutrient elements) mineral fertilizers is their preparation from purchased high-grade soluble fertilizers and purchased or obtained deionized (distilled) or deeply softened water that does not contain components that precipitate in phosphate or sulfate environments. For example, the method known for fertigation is known according to the USSR author's certificate No. 82032 (sub. To oven. 04/05/1961) [1], according to which a nutrient solution of mineral fertilizers in water is prepared and used to feed plants by piping also intended for irrigation.

When using fertilizers and high quality water, the approach inherent in this and similar methods is expensive. When using low-grade fertilizers and low-quality water containing harmful impurities, another drawback of such methods is manifested: an increased content of agrochemically harmful components in the resulting solution, for example, chlorides and heavy metals. Also, the content of sediment-forming components in fertilizers and the water itself limits the field of application of the obtained solutions — colloids and precipitates may be formed that do not allow the use of the obtained liquid products during drip irrigation due to clogging of nozzles of fertigation devices.

Therefore, various techniques are developed to reduce the corresponding costs. In this regard, the method according to the patent of the Russian Federation No. 2138149 (publ. 09/27/1999) [2] and the method according to the patent of the Russian Federation No. 2281255 (publ. 08/10/2006) [3] are based on the following idea: before applying fertilizers, including simple and low-grade, highly concentrated solutions from these fertilizers are prepared for the corresponding agricultural plot and, using the obtained solutions, they “charge” cation exchange resin and anion exchange resin in ion-exchange columns, i.e. convert the ion exchangers into the corresponding ionic forms. For example, using relatively cheap simple fertilizer - potassium chloride, you can convert cation exchange resin to the K-form, and using ammonium nitrate (or sodium nitrate) convert the anion exchange resin to the nitrate form. During this transfer, a concentrated solution of sodium chloride or ammonium chloride is obtained, which can be disposed of directly or after appropriate treatment. Then, brackish water produced near the same site, for example, from underground sources, is successively passed through cation exchange resin and anion exchange resin. The result is a clean solution of potassium nitrate - an expensive complex and chlorine-free fertilizer that can be used for fertigation, including drip irrigation. In the same way, it is possible to obtain solutions of potassium sulfate or potassium hydrogen phosphate by “charging” anion exchange resin with cheaper sodium sulfate (or ammonium sulfate), or, respectively, sodium phosphate (or monoammonium phosphate), which is much cheaper than the resulting monopotassium phosphate. You can also get different solutions of complex fertilizers and mix them in the appropriate proportions required for the content of macrocomponents: nitrogen, phosphorus and potassium (NPK), mesocomponents, including sulfur, and useful trace elements in the final mixed solutions of complex fertilizers.

With the successive transmission of brackish natural water through columns with cation exchange resin and anion exchange resin, the latter sorb, respectively, the cationic and anionic components of this water. The ratio of the flows passing through the ion exchangers in the columns to the volumes of these ion exchangers is selected so that their processing time is the same. After this, cation exchange resin and anion exchange resin regenerate, i.e. “charged” with concentrated solutions of selected feedstock fertilizers.

An important factor of this process is that in the ion exchange there is a phenomenon of electrical selectivity, namely, the selectivity of sorption of doubly and multiply charged ions with respect to singly charged ions is significantly higher from dilute solutions than from concentrated solutions (F. Helferich. Ionites. M. , Publishing House of Foreign Literature, 1962, S. 153-155 [4]). Because of this, similar components, for example, hardness ions, which may be present in the composition of brackish water itself, are retained by the ion exchanger in each sorption cycle during the passage of this water through the column, i.e. such components do not enter the resulting fertilizer solution, but they are washed out of the cation exchange column during regeneration, i.e. when "charging" using concentrated solutions of source fertilizers. Thus, there is a second, “hidden” advantage of the methods built on the idea under consideration. The part of the water that is obtained in the final fertilizer solution no longer contains harmful or sediment-forming impurities, so the consumer is relieved of the need to desalinate the appropriate amount of water, which also reduces the cost of obtaining pure solutions of high-grade soluble fertilizers.

The disadvantage of one of such methods based on the described idea, namely, the method [2] is that it does not allow you to adjust the balance of water and fertilizer. If natural brackish water is too concentrated, then fertilizer solutions are obtained in the same concentration and, as a rule, there is still not enough water to ensure the optimal ratio of components during irrigation with the simultaneous application of fertilizers. Another disadvantage of this method is described below in the discussion of the method [3].

In the method [3], which is the closest to the proposed method, the problem of water-salt balance is solved. This method of treating brackish water involves sequentially passing them through cation exchange resin and anion exchange resin in ionic forms containing, as cations and anions, elements that are part of the resulting complex mineral fertilizer. The water to be treated is first passed through a cation exchange resin, and the outgoing diluted solution is divided into two parts, and one part is passed through anion exchange resin and the other through an electrodialysis desalination plant. The stream obtained after passing through the anion exchange resin and the desalinated water stream obtained in the electrodialysis apparatus are mixed before being fed for irrigation, and the salt concentrate from the electrodialysis apparatus is returned to the process to the cateonite treatment step. In this case, the regeneration of cateonite and anion exchange resin is carried out by treating them with concentrated solutions of salts containing the corresponding ionic components of the resulting fertilizer, using simple low-grade mineral fertilizers for this.

However, the method [3] (as well as the method [2]) has the disadvantage that when the content of harmful or sediment-forming components is not only in the source water, but also in the initial low-grade fertilizers, such components can enter the purified prepared solutions and result to the following two undesirable consequences: a) failure of a desalination plant, such as an electrodialysis plant; b) the appearance of colloids or sediments in the final solution. In this regard, the scope of the method [2] is limited, in particular, for drip irrigation.

On the other hand, the lower the grade of the used fertilizers or salts, the more profitable it is to carry out ion-exchange methods for preparing solutions for fertigation. It is most expedient to use, for example, potassium chloride and ammonium chloride as low-grade salts or fertilizers for “charging” cation exchange columns. The composition of the latter, as a rule, is more strictly standardized and in the worst case (NH ₄ Cl technical, 2nd grade) the iron content does not exceed 0.01%, heavy metals - not more than 0.0025%, and insoluble impurities - not more than 0 , 05%. A certain danger can be represented only by small impurities of stiffness cations, which are not standardized. Significantly more "dirty" are the most available as fertilizers varieties of potassium chloride. In accordance with GOST 4586-95, granular potassium chloride must contain at least 58% potassium in terms of potassium oxide. This represents only 92% KCl in the main product. Impurities of iron and doubly charged ions are not normalized.

Since these salts and fertilizers, in particular potassium chloride, are used in the composition of the concentrated regenerating solution to “charge” the cation exchanger, they are passed through the columns in the direction from the bottom up. Less dense brackish water is passed from top to bottom. This mode allows you to avoid mixing solutions of different densities and the formation of additional volumes of liquid waste. However, the effect of electrical selectivity does not allow the ingress of harmful impurities into the diluted solution of complex mineral fertilizer obtained at the outlet of the cation exchange column. When the initial brackish water is passed through, the intrinsic impurities of this water can be absorbed in the upper part of the column, but some of the impurities introduced, for example, together with a concentrated solution of potassium chloride and accumulated in the lower part of the column at the “charging” stage, are taken out together with a diluted solution of potassium salts, obtained at the stage of passing the initial brackish solution through the K-form of cation exchanger in each working cycle.

It is the flow of this solution in accordance with the method [3] is divided into two parts. The first of them directly enters the electrodialysis desalination apparatus, and therefore the presence of impurities in it leads to a decrease in the desalination efficiency and premature failure of the apparatus. The second part passes into the anion exchange column, which can be, for example, in sulfate or hydrophosphate form, and then impurities will lead to the formation of colloids and precipitates in it.

Thus, the method [3] allows the use of low-quality natural brackish water (which can be preliminarily subjected to mechanical filtration and deferrization by known technologies for subsequent ion exchange treatment). But this method does not provide the possibility of using available simple and (or) low-grade types of feed fertilizers or salts, and thereby reduces the efficiency of the ion-exchange technology for producing solutions of complex high-grade mineral fertilizers.

In addition, if sulfates or carbonates are present in the source natural water, the latter can be returned to the first (cationite) ion exchange column with salt concentrate from the desalination apparatus used as a regenerating solution for the ion exchanger of this column. When interacting with calcium contained in the source water, such sulfates and carbonates can form insoluble or difficultly soluble compounds and lead to the appearance of precipitates in the columns, and, when removed with effluent solutions, make it difficult to directly utilize them and process them. At the same time, sulfate and carbonate anions falling into sediments and effluents could be useful ionic components of complex mineral fertilizers.

Another disadvantage of the method [3] is that, as a rule, the processing of cation exchanger and anion exchanger (for “charging” the ion exchanger) requires a significantly larger equivalent amount of simple or low-grade fertilizer than can be obtained in a solution of a ready-made complex fertilizer. This can be illustrated by the example of cation exchange resin: the process of passing a brackish solution through the potassium or ammonium form of cation exchange resin is essentially a process of softening brackish water, and the subsequent processing of cation exchange resin provides for its complete regeneration from sorbed multiply charged components, which takes significantly more than one equivalent potassium or ammonium chloride in a concentrated solution for processing. This drawback leads not only to an overestimated consumption of the initial simple and (or) low-grade fertilizers, but also to the formation of increased volumes of concentrated concentrated effluents when they are passed through the ion exchangers that require disposal to ensure the environmental safety of the process.

The proposed method is aimed at overcoming the interrelated problems described above and achieving a technical result, which consists in providing the possibility of using low-grade fertilizers, mainly potassium chloride, while reducing their consumption and additionally, in combination with achieving a close to continuous nature of the process, as well as increasing its environmental safety in combination with increasing the yield of complex mineral fertilizers obtained while reducing holding the components forming insoluble precipitates in the waste and recycled solutions. Below, when disclosing the essence of the present invention and considering particular cases and examples of its implementation, other types of technical result achieved can be named.

In accordance with the invention, a method for processing natural brackish water to obtain a solution of complex mineral fertilizers, as well as the closest known method according to the patent [3], includes the implementation of a cyclically repeated process. In each cycle of this process, the operation of sequentially passing natural brackish water supplied from the tank for the water to be processed and intermediate solutions of its processing from top to bottom through the first and second ion-exchange columns containing ion exchange resin, respectively, in the form of an agrochemically valuable cationic component and agrochemically performed valuable anionic component of the obtained complex mineral fertilizer, as well as the operation of the regeneration of ion exchangers in ion-exchange columns, in which I regenerate s solution is fed into each ion exchange column in an upward direction from shared with the given capacity column for such a solution. In addition, carry out the separation of the flow of the intermediate solution of the processing of natural brackish water into two parts. The first part is sent to the second ion-exchange column to obtain a solution stream of a complex mineral fertilizer at its outlet, and the second part - to desalination to obtain a salt concentrate and a stream of demineralized water to dilute the solution of a complex mineral fertilizer and other purposes. The ionite regeneration operation in each cycle is carried out using the specified salt concentrate obtained by desalination as part of the regenerating solutions, as well as concentrated solutions of two salts, one of which contains an agrochemically valuable cationic component, and the other an agrochemically valuable anionic component of the resulting complex mineral fertilizer.

In contrast to the closest known method, in the proposed method, to achieve the above technical result, a third ion-exchange column containing an ion exchanger in the form of the specified cationic component is additionally used, as well as a container for an ion exchanger regenerating solution of this column, and natural brackish water is passed through this column before passing through the first ion exchange column in the direction from top to bottom. The stream from the outlet of the first ion-exchange column is sent to nanofiltration to separate substances with singly charged anions and substances with multiply charged anions to obtain their solutions, respectively, in the form of permeate and concentrate, and the above two parts of the stream of the intermediate solution of processing natural brackish water are obtained by separation into two parts permeate after nanofiltration. The concentrate obtained after nanofiltration is sent to the process outlet as an additional stream of the obtained complex mineral fertilizer. The salt concentrate obtained by desalination is used as a regenerating solution for the regeneration of ion exchanger in the first ion exchange column. To regenerate the ion exchanger in the third ion exchange column, use the regenerate obtained by regenerating the ion exchanger in the first ion exchange column, together with the specified concentrated salt solution containing the agrochemically valuable cationic component of the resulting complex mineral fertilizer, and pass the regeneration solution through the third ion exchange column from the bottom up. For ionite regeneration in the second ion-exchange column, the indicated concentrated salt solution containing the agrochemically valuable anionic component of the resulting complex mineral fertilizer is used. In this case, the regenerating solution is passed through the first and third ion-exchange columns during the time before the breakthrough at the outlet of the third ion-exchange column of the indicated agrochemically valuable cationic component and through the second ion-exchange column during the time before the breakthrough at its exit of the specified agrochemically valuable anionic component, and the operation sequential transmission of natural brackish water and intermediate solutions for its processing through ion-exchange columns is performed over time before a breakthrough occurs at the outlet of the first or second ion-exchange column of any of the agrochemically harmful ionic components contained in natural brackish water or salts used in the composition of regenerating solutions.

As these salts, the concentrated solutions of which are used in the operation of the regeneration of ion exchangers, it is advisable to use readily available low-grade simple fertilizers.

Only a small part of the harmful ions “slip” from the first layer of cation exchange resin located in the optionally used third ion exchange column into the second cation exchange layer located in the first column. The second layer, located in the first ion-exchange column, does not allow these ions to desalinate, and also does not allow for further processing impurities that may be contained in the regenerating solution when using low-grade fertilizer (namely, the use of such inexpensive fertilizers, as noted above, focuses on the proposed invention) and could lead to the formation of colloids and precipitation. When nanofiltration is carried out, the separation of "heavy" molecules of sulfates and (or) carbonates present in the processed solution occurs due to the presence of the corresponding ions in the original natural brackish water. Combining with an agrochemically valuable cationic component during ion exchange in the third and first columns, sulfate and (or) carbonate anions form useful substances - complex fertilizers, which in a particular case can be the same as those obtained at the outlet of the second (anion exchange) column . In the form of a concentrate stream after nanofiltration, they are fed to the process outlet as an additional stream of the obtained complex mineral fertilizer.

At the same time, due to the fact that the permeate supplied for desalination after nanofiltration does not contain the indicated sulfates and carbonates, the salt concentrate obtained after desalination is also free from them. It is a high-quality regenerating solution used to regenerate the ion exchanger in the first column. As a result, the formation of calcium sulfate and calcium carbonate and their ingress into the effluent during the ion exchange regeneration operation is prevented, and the increased content of sulfates and carbonates in the original natural brackish water not only does not interfere with the use of the proposed method, but also allows to increase the yield of the obtained complex mineral fertilizer .

After regeneration of the cation exchanger layer located in the first ion exchange column (second layer), the concentrate is the main regenerating solution for the layer in the third ion exchange column (first layer). It contains less multiply charged ions than the solution of the initial simple fertilizer, which in the proposed method (in contrast to the method [3]), as mentioned above, is used in much smaller quantities. Salt in the form of an initial low-grade fertilizer, the impurity components of which, as a result of ion exchange during regeneration, may appear on the cation exchange resin of the third column, is not involved in the regeneration of the ion exchanger of the first column.

Moreover, the presence of a third ion-exchange column requiring regeneration does not lead to an increase in the consumption of simple fertilizer used for this purpose, since the regeneration of the ion exchanger of this column is carried out mainly by the regeneration of the first column. On the contrary, the indicated flow rate can even be reduced as a result.

Among the features of the proposed method, one can notice the presence of such well-known techniques as incomplete regeneration of ion exchangers in columns, the use of saline concentrate obtained by desalination for the recovery of cation exchange resin (which also occurs in the closest known method), nanofiltration. However, only the joint implementation of these features in combination with the presence of a third column in the natural brackish water processing chain allows the cation exchanger to be regenerated in the first column without using salt in the form of an impurity source simple fertilizer. Moreover, it is due to the presence of the third column that the impurity components of the simple fertilizer used fall into the first column as part of a diluted (rather than concentrated) solution. This creates the conditions for the manifestation of the aforementioned effect of electroselectivity and the successful completion of the sorption of such components in the first column. Thanks to the implementation of nanofiltration, the concentrate after desalination is freed from the "heavy" molecules contaminating it, which improves the quality of the solution used for the regeneration of cation exchange resin in both the first and third columns, further improves the indicated sorption and at the same time makes these molecules useful components of the additionally obtained fertilizer. Along with this, the described features in the aggregate can reduce the consumption of simple fertilizers used.

In this regard, the proposed method is close to the so-called self-sustaining processes of ion-exchange sorption, used in softening-desalination of sea water (Tokmachev MG, Tikhonov NA, Khamizov R.Kh. Investigation of cyclic self-sustaining process for softening water solutions on the basis of mathematical modeling React. Funct. Polym., 2008, V. 68, P. 1245-1252 [5]). For such processes, it is typical that in stationary mode they can be carried out without the use of additional reagents for sorbent regeneration. In other words, in such a process, the equivalent amounts of the sorbed components and the regenerating agent are equal to each other.

The proposed method can be called a combined self-sustaining cyclic sorption-desorption process in a column system with specially organized interconnections, in which two types of interconnected flows are also involved: 1) flows of low-grade fertilizer solutions containing the ionic components necessary to obtain complex fertilizer used in primary (partial) regeneration of ion exchangers, namely, for almost complete replacement of macro components sorbed from the initial solution, and partial replacement of sorbi harmful harmful microcomponents, also from the same solution; 2) the concentrate stream after the desalination plant, obtained from the initial solution after sorption removal of harmful ionic components from it on the regenerated forms of cation exchangers, used to ensure the complete (final) regeneration of cation exchangers.

If we imagine the sum of the equivalents of all components that are retained on the ion exchangers during the sorption stages, then in each cycle of the repeating process the indicated amount is exactly equal to the sum of equivalents in solutions for regeneration from flows 1) and 2).

It was not obvious whether and how to provide such a combined, self-sustaining process. It turned out that due to the noted combination of features of the proposed method, it is possible to implement a process with indicators that bring it as close as possible to a self-sustaining process of the above type, despite the fact that in traditional sorption processes, the necessary costs of the regenerating agent are several times higher than the equivalent amount of sorbed components (this situation has place, for example, in the processes of countercurrent ion-exchange water treatment: A. V. Zhadan, E. N. Bushuev. I counter-current ion exchange technology. "Journal of Ivanovo State Power University," Vol. 5, 2012, pp 1-6 [6]).

The addition of the proposed method with the features discussed below contributes, along with the other types of technical result described, to further bring it closer in properties to self-sustaining processes.

A factor ensuring the equally equivalent consumption of sorbed and desorbing (regenerating) components is also the displacement at each stage of each cycle of the repeating process of the solutions remaining in the free space of the columns from the previous stage, their preservation and use at the next stage of the next cycle.

In the particular case of performing the method in each cycle at the beginning of the operation of sequentially passing through the ion-exchange columns natural brackish water and intermediate solutions for its processing, the displaced regenerating solution remaining in the free volume of each ion-exchange column (i.e., in the porous space between the ion exchanger grains, as well as above layer and under a layer of ion exchanger) from an ion exchanger regeneration operation performed in a given column, is sent to a container for a regenerating solution used in conjunction with this column oh.

This allows not only to correspondingly reduce the volume of effluent solutions, but also helps to reduce the consumption of salts used (simple or low-grade fertilizers), since the solution displaced into the indicated tank, which retains its properties as a regenerating one, is used in subsequent cycles.

In addition, an intermediate tank is additionally used, and in each cycle when performing the operation of sequentially passing natural brackish water and intermediate solutions for its processing, the first part of the permeate stream obtained after nanofiltration and sent to the second ion-exchange column is preliminarily fed into this tank, in which to this part add the solution which is displaced at the beginning of the ion exchange regeneration operation, remaining in the free volume of the second ion exchange column from before this, the operations of sequentially passing natural brackish water and intermediate solutions of its processing, and the mixed solution obtained in the intermediate tank is sent to this column, and the solution remaining in the free volume of the first and third ion-exchange columns, displaced at the beginning of the ion exchange regeneration operation, is sent to capacity for natural brackish water to be processed.

This allows you to save for future use a certain amount of the solutions processed in the columns, in which exchange for agrochemically valuable ionic components has already been carried out, and also helps to reduce the consumption of simple or low-grade fertilizers, and also reduces the volume of waste solutions by the volume of the indicated displaced solution.

In another particular case, as in the previous one, an intermediate tank is additionally used, and in each cycle the first part of the solution stream leaving the first ion-exchange column directed to the second ion-exchange column is preliminarily fed into this container, in which the displaced at the beginning is added to this part of the ion exchange regeneration operation, the solution remaining in the free volume of the second ion exchange column from the previous operation of sequential transmission of natural brackish water and intermediate solutions of its processing, and the mixed solution obtained in the intermediate tank is sent to this column, and the solution remaining in the free volume of the first and third ion-exchange columns, displaced at the beginning of the ion exchange regeneration operation, is sent to the tank for the natural brackish water to be processed. In addition, in this case, together with each of the indicated first, second, and third ion-exchange columns, an auxiliary tank is additionally used and in each cycle at the beginning of the sequential transmission of natural brackish water and intermediate solutions for its processing, the displaced regeneration solution remaining in the free volume of the ion-exchange column in which such an operation is performed after the ionite regeneration operation in the column is carried out before, it is sent to the indicated auxiliary capacity spine and in the performance of ion exchangers before feeding the next regeneration step in ion exchange column regenerant solution from the tank to this solution, a solution which is in this auxiliary tank.

In this case, the displaced regeneration solution does not mix with the solution initially supplied to the container for such a solution, which ensures greater stability of the properties of the regeneration solution, but compared with the previous one, this case requires a larger amount of equipment.

In the process of implementing the proposed method, when using the saline concentrate obtained by desalination as a regenerating solution in the operation of ion exchanger regeneration in the first ion exchange column, a concentrated salt solution containing an agrochemically valuable cationic component of the resulting complex mineral fertilizer can be added to each concentrate in a cycle that is more pure the content of impurities compared with the salt used in a concentrated solution for the regeneration of ion exchange resin a third ion exchange column, with the amount of such a salt being added to the concentrated solution, equal to an equivalent amount of said cationic component is handed down in the composition obtained after desalination desalted water. This addition allows you to compensate for the missing amount of salt containing the specified cationic component, if there is an excess removal of such salt with demineralized water. In this case, a solution of the added salt is used, as well as a salt solution used in the regeneration of the ion exchanger in the third ion exchange column, with the same concentration as the salt concentrate obtained by desalination, which simplifies process control.

As cation exchange resin and anion exchange resin in ion-exchange columns, it is preferable to use, respectively, strongly acid sulfocationionite and strongly basic anion exchange resin with quaternary ammonium bases.

Such ion exchangers are the most stable and durable, and when using them, a large number of sorption-regeneration cycles are possible. In addition, their use does not lead to the formation of specific complexes that require application in the regeneration of acids or alkalis, which allows salt regeneration to be dispensed with.

In all the above and other cases of the implementation of the proposed method in each cycle, the operation of regeneration of ion exchangers and the operation of sequential transmission of natural brackish water and intermediate solutions of its processing can be carried out in parallel. For this, ion-exchange columns are additionally used, forming, respectively, the first, second and third pairs with the indicated first, second and third ion-exchange columns and containing the same ion exchanger. In this case, each of these containers for the regenerating solution, as well as each of the auxiliary containers, when such tanks are used, are common to both ion exchange columns forming a pair. During one half of the cycle when using one of the ion-exchange columns of each pair in the operation of sequentially passing natural brackish water and intermediate solutions for its processing, another ion-exchange column of the same pair is used in the operation of regeneration of the ion exchanger, and in the other half of the cycle, the types of operations in which ion exchange columns of the specified pairs.

The use of pairs of columns allows not only to double the productivity of the process, but also to make it practically continuous. This is achieved due to the fact that in this case not only two simultaneously occurring identical processes are implemented (in which parallel execution of the same operations in different columns would be provided, for example, in one of the particular cases of the method [2]), but parallel execution of different operations in two columns forming a pair. As a result, during the half-cycle in which, when implementing the proposed method without the use of paired columns, there would have been a break in obtaining a complex fertilizer stream from the output of a single second column, when using paired columns, such a stream is obtained from the output of another column forming a pair with the specified second column .

To increase the environmental safety of the technological process when applying the proposed method, waste solutions in the form of regenerates obtained during ionite regeneration operations in the second and third ion-exchange columns can be combined and then sent for processing by vacuum crystallization.

During desalination, any method from the group including electrodialysis, reverse osmosis method, thermodistillation method, and also cold distillation methods — the vaporization method and the method of capacitive distillation — can be used.

The solution of complex mineral fertilizer obtained at the exit of the second ion-exchange column, as well as an additional stream of the obtained fertilizer, which is the concentrate after nanofiltration, can be diluted with desalted water obtained after desalination to achieve the concentration necessary for fertigation.

The discussion of the features of the invention related to the proposed method will be continued after the summary of the inventions related to the installation options for implementing the proposed method, as well as when considering examples.

The installation for implementing the proposed method is described below in two versions, each of which in particular cases involves the use of pairs of ion-exchange columns.

From the patent [2] there is known a plant for processing natural brackish water to produce solutions of complex mineral fertilizers, containing an ion-exchange column with cation exchange resin and an ion-exchange column with anion exchange resin, respectively, in the forms of cationic and anionic components of the resulting complex mineral fertilizer, two containers for regenerating solutions representing concentrated solutions of two salts (which are used as simple source fertilizers), each of which contains one of the ionic components of the semi complex fertilizer. These tanks and columns are connected to each other and to the tank for recycled water, as well as to the tank for waste solutions by lines containing switching valves and pumps, so that the mode of sequential transmission of natural brackish water through the said columns from top to bottom and the transmission mode through each from them from bottom to top of the corresponding regenerating solution. In the first of the mentioned modes, a solution of a complex mineral fertilizer comes out of an ion-exchange column with anion exchange resin, for which this unit is intended.

When using this installation to obtain a fertigation solution of the required concentration, it is necessary to have a separate source of fresh water, which narrows the possible field of its application.

Both options of the proposed installation for processing natural brackish water to produce complex mineral fertilizers are closest to the known installation according to the patent [3], free from this drawback. It provides the possibility of obtaining desalted water for the required dilution of the resulting solution of complex mineral fertilizers. For this, in addition to the facilities included in the installation of the patent [2], the installation of the patent [3] is equipped with a desalination apparatus and a container for preparing the resulting fertilizer, in which desalinated water is mixed from the desalination apparatus for such water with a solution of complex mineral fertilizer, obtained from the output of an ion exchange column with anion exchange resin. The inlet (upper in this operation) pipe of this column and the inlet of the desalination apparatus are connected to the output pipe of the ion exchange column with cation exchange resin (lower in this operation) through valves to control the flow ratio resulting from the separation of the flow from the output of the ion exchange column with cation exchange resin. When regenerating cation exchange resin in this column, salt concentrate from a desalination apparatus is additionally used, for which its corresponding output is connected to a capacity for a regenerating solution for the specified column.

However, such a setup has an inherent drawback, which, as noted above in the description of the proposed invention relating to the method, when using low-grade simple fertilizers containing agrochemically harmful impurities. The design of this installation does not prevent the ingress of such impurities into the complex fertilizer obtained at its output. Penetration of impurity components into the column with anion exchange resin can lead to the formation of colloids and precipitates in it, and their ingress to the desalination unit inlet causes a decrease in the quality of desalination and, in addition, can lead to premature failure of the desalination unit. In addition, in the presence of sulfates and carbonates in the natural brackish water used, the corresponding ions that enter the cation exchange column with the salt concentrate from the desalination apparatus during the ion exchange regeneration operation can form insoluble or difficultly soluble calcium compounds in the source water, precipitate in the column itself and enter the discharged regenerate, forming a non-recyclable waste.

The proposed invention, relating to two versions of the installation for processing natural brackish water to produce complex mineral fertilizers, is aimed at achieving a technical result consisting in improving the quality of the resulting fertilizer by reducing the content of agrochemically harmful components in it, which are inevitably present in practically used low-grade fertilizers, and also in improving the reliability of the installation, including by improving the working conditions of the desalination unit ata due to the best previous cleaning of the solution supplied to its input, and in preventing environmentally harmful discharges. In addition, during the operation of the proposed installation, conditions are created to reduce the consumption of initial fertilizers due to the convergence of equivalent amounts of ionic components contained in the initial simple fertilizers and the resulting complex fertilizer. At the same time, it is possible to obtain an additional amount of complex mineral fertilizer by involving in the processing the sulfates and carbonates contained in the source natural water while preventing the formation of compounds of the corresponding ions with calcium, their sedimentation in columns and getting into effluent solutions. Below, when disclosing the essence of the present invention, other types of achievable technical result can be named.

The proposed installation according to the first embodiment for the processing of natural brackish water on ion exchangers to obtain a solution of complex mineral fertilizer, as well as the closest known to it [3], contains a tank for natural brackish water to be processed, having an outlet and inlet nozzles, first and second ion-exchange columns having each of the upper and lower drainage devices, respectively, with the upper and lower nozzles, the first and second containers for regenerating solutions, having each inlet and outlet nozzles. The installation also contains a desalination apparatus having an inlet pipe, an outlet pipe for demineralized water, and an outlet pipe for salt concentrate. In this case, the first ion exchange column contains cation exchange resin, and the second contains anion exchange resin in the form, respectively, of agrochemically valuable cation and anion components of the resulting complex mineral fertilizer.

To achieve the above technical result, the proposed installation according to the first embodiment, in contrast to the one closest to it, contains first, second and third ion-exchange units, each of which contains an ion-exchange column having upper and lower drainage devices, respectively, with upper and lower lower branch pipes. Each ion-exchange unit contains, in addition, a container for a regenerating solution having an outlet pipe and an inlet pipe, which is the first input of the ion-exchange unit and is intended for supplying a regenerating solution to it, as well as the first and second flow switches. The latter have four nozzles and are made with the possibility of connecting the third nozzle to the first, second or fourth. The third nozzles of the first and second flow switches are connected, respectively, with the upper and lower nozzles of the ion exchange column. The second branch pipe of the first flow switch is the second input of the ion-exchange unit, which is designed to supply the solution processed in the ion-exchange column. The first branch pipe of the first flow switch is the first output of the ion exchange unit, which is designed to remove the regenerate from the ion exchange column. The fourth branch pipe of the first flow switch forms the third exit of the ion-exchange unit, which is designed to remove the processed solution displaced from the free volume of the ion-exchange column. The outlet pipe of the tank for the regenerating solution is connected to the first pipe of the second flow switch. The second pipe of the second flow switch is the second output of the ion-exchange unit, which is designed to remove the solution processed in the ion-exchange column. In this case, the ion-exchange columns of the first and second ion-exchange units are, respectively, the indicated first and second ion-exchange columns, and the capacities of these ion-exchange units for regenerating solutions are, respectively, the indicated first and second containers for regenerating solutions. The ion exchange column of the third ion exchange site contains cation exchange resin in the form of an agrochemically valuable cationic component of the resulting complex mineral fertilizer. The capacity for the regenerating solution in this ion-exchange unit has an additional inlet pipe, which is the third input of this ion-exchange unit, which is designed to supply a salt solution containing an agrochemically valuable cationic component of the resulting complex mineral fertilizer. In addition, the capacity for the regenerating solution in each ion-exchange unit is provided with another inlet pipe connected to the fourth pipe of the second flow switch. The proposed installation according to the first embodiment also contains an intermediate tank having two inlet nozzles and an outlet nozzle. In this case, the second inlet of the third ion-exchange unit is connected to the outlet pipe of the tank for the natural brackish water to be processed. The second output of this ion-exchange unit is connected to the second input of the first ion-exchange unit, the first output of which is connected to the first input of the third ion-exchange unit. The first input of the first ion-exchange unit is connected to the outlet pipe of the desalination apparatus for salt concentrate. The first input of the second ion-exchange unit is designed to supply a salt solution containing an agrochemically valuable anionic component of the resulting complex mineral fertilizer, and its second output is the output of the specified installation for the resulting solution of complex mineral fertilizer. The proposed installation according to the first embodiment is also equipped with a nanofiltration unit for separating substances with singly charged anions and substances with multiply charged anions, having an inlet pipe connected to the second output of the first ion-exchange unit, an output pipe for permeate and an output pipe for concentrate, which is the output of the specified installation for the resulting in it an additional solution of a complex mineral fertilizer. The outlet pipe for the permeate of the nanofiltration unit is connected to the inlet pipe of the desalination apparatus and one of the inlet pipes of the intermediate tank with the ability to control the ratio of flows arising from this separation of the flow from the outlet pipe of the nanofiltration unit for permeate. The third output of the second ion-exchange unit is connected to another inlet pipe of the intermediate tank, and the second input of the second ion-exchange unit is connected to the output pipe of the intermediate tank. The third exits of the first and third ion-exchange units are connected to the inlet pipes of the tank for the natural brackish water to be processed, and the first exits of the second and third ion-exchange units are the outputs of the indicated installation for waste solutions.

Of course, here and everywhere in the future, the use of the phrase “with the possibility of connecting pipes ...” to characterize the function of the flow switches does not exclude the possibility of finding one or another flow switch in the state when it is “closed”, i.e. not one of the connections of its nozzles is carried out.

The features of the installation of the described construction compared with the closest known one [3] are, along with the fact that it is based on three ion-exchange units of identical structure, in the presence of a total of three ion-exchange columns and means for switching fluxes, including , feeding into an additionally introduced (third) column, which is part of the third ion-exchange unit, as a regenerating solution of the regenerate column of the first node. The mentioned column precedes the column of the first ion-exchange unit, which is also contained in the closest known installation, which, in contrast to the closest known installation, does not participate in the salt in the form of the initial low-grade fertilizer along the flow of natural brackish water being processed. The impurity components of such a fertilizer may, as a result of ion exchange during regeneration, end up on the cation exchange resin of the third unit column. During ion exchange, passing natural brackish water, they can enter the solution emerging from this column. But they do not enter the inlet of the desalination apparatus and the inlet of the column of the second unit, since the specified solution passes through the column of the first unit in advance, the cation exchange resin is regenerated with salt concentrate supplied from the corresponding outlet of the desalination unit, without using the initial fertilizer. In turn, the said concentrate is therefore cleaner and is a high-quality regenerating solution. At the same time, the presence of an additionally introduced ion-exchange column, which is part of the third ion-exchange unit, which requires regeneration, does not increase the consumption of simple fertilizer used for this purpose, since the ion exchanger of this column is mainly regenerated by the column regeneration of the first node, supplied along with such fertilizer into the container for the regenerating solution of the third node. Ultimately, the operation of the installation is possible not only without an increase in the consumption of simple fertilizers, but also with a decrease in comparison with the closest known installation and with a higher purity of demineralized water. The quality of the fertilizer obtained increases both for this reason and due to the greater purity of the intermediate solution for processing natural brackish water entering the ion-exchange column of the second node with anion exchange resin. In addition, the formation of colloids and sediments in the anion exchange column of the second ion-exchange unit, which would be possible due to the ingress of impurity components therein, is prevented.

Further, the installation comprises a nanofiltration unit connected by its input to the second output of the first ion-exchange unit. When nanofiltration is carried out, the separation of "heavy" molecules of sulfates and carbonates occurs, which appeared in the processed solution due to the presence of the corresponding ions in the original natural brackish water. Combining with ions of agrochemically valuable components in the process of ion exchange, they form the indicated sulfates and carbonates, which are useful substances - complex fertilizers, which in a particular case can be the same as those obtained at the outlet of the second (anion exchange) column. In the form of a concentrate from the corresponding output of the nanofiltration unit, they are fed to the output of the installation as an additional stream of the resulting complex mineral fertilizer. At the same time, due to the fact that the permeate supplied for desalination after nanofiltration does not contain the indicated sulfates and carbonates, the salt concentrate obtained after desalination is also free from them. Since it is a high-quality regenerating solution used to regenerate ion exchanger in the first column, the formation of calcium sulfate and calcium carbonate and their ingress into the effluent during the ion exchanger operation is prevented. Therefore, the increased content of sulfates and carbonates in the source of natural brackish water is not only not an obstacle to the use of the proposed method, but also allows you to increase the yield of complex mineral fertilizers.

The described implementation of the means of switching flows in the installation allows, at the beginning of the operation of passing natural brackish water, to displace from the columns the regenerating solution remaining after the previous regeneration operation into the tank for such a solution of the corresponding ion-exchange unit, where this solution is combined with the regenerating solution supplied from the outside. This, in turn, allows not only to correspondingly reduce the volume of effluent solutions, but also helps to reduce the consumption of salts used (simple or low-grade fertilizers), since the solution displaced into the indicated container, retaining its properties as a regenerating one, is used in subsequent cycles.

In addition, it becomes possible at the beginning of the operation of passing the regenerating solution through the column of each of the ion-exchange units to collect the displaced processed solution remaining in the free volume of the column after the previous operation of passing natural brackish water: from the columns of the first and third nodes - directly into the tank for the natural brackish to be processed water, and from the column of the second ion-exchange unit into a separate intermediate tank. Thanks to this, it is possible to prevent the discharge of such solutions containing useful ionic components, and save them for future use.

As a result, the design features of the installation related to the control of the flows of displaced solutions contribute to an additional reduction in the consumption of salts used for the regeneration of ion exchangers (i.e., simple low-grade fertilizers) and, at the same time, the environmental safety of the process implemented in the installation, as well as, as already noted, the possibility of obtaining additional amounts of complex mineral fertilizers.

In the particular case, the capacity for the regenerating solution in the first ion-exchange unit can be equipped with an additional inlet pipe, which forms the third inlet of this ion-exchange unit, designed to supply an additional component of the regenerating solution for the used cation exchange resin of this ion-exchange unit. Such a component is a salt solution that is cleaner in impurity content compared to the salt (simple fertilizer) used in the solution supplied to the third input of the third ion-exchange unit. An additional component may be required to compensate for the (insignificant) amount of salt removed with desalted water from desalination.

In the proposed installation according to the first embodiment, the desalination apparatus can be configured to implement any desalination method from the group including electrodialysis, reverse osmosis method, thermodistillation method, and also cold distillation methods — the vaporization method and the method of capacitive distillation.

As the cation exchange resin and anion exchange resin in the columns of the ion-exchange units of the installation according to the first embodiment, it is preferable to use, respectively, strongly acid sulfocationionite and strongly basic anion exchange resin with quaternary ammonium bases. Such cation exchangers and anion exchangers are the most stable and durable, and when using them, a large number of sorption-regeneration cycles are possible. In addition, their use does not lead to the formation of specific complexes that require application in the regeneration of acids or alkalis, which allows salt regeneration to be dispensed with.

In the proposed installation according to the first embodiment, each of the following compounds is: a second inlet of a third ion-exchange unit with an outlet pipe of a container for water to be processed, an outlet pipe of a desalination apparatus for salt concentrate with a first input of a first ion-exchange unit, an outlet pipe of an intermediate tank with a second input of a second ion-exchange unit and the outlet pipe of the tank for the regenerating solution with the first pipe of the second flow switch in each ion-exchange unit can be implemented but the line containing the pump. This allows you to adjust the flow rate regardless of the relative position of the ion-exchange columns and containers used.

To obtain products that are waste in an easily utilized form and to reduce their volume to obtain additional fresh water, the installation may additionally contain a vacuum crystallization apparatus and a container for waste solutions having inlet and outlet pipes. In this case, the vacuum crystallization apparatus is connected at its inlet to the outlet pipe of the indicated capacity, and the inlet pipes of this tank are connected to the first outputs of the second and third ion-exchange units.

The installation may further comprise a container for preparing a dilute solution of the obtained complex mineral fertilizer having an outlet and inlet pipes, and a storage tank for demineralized water having an inlet and outlet pipes. In this case, one of the inlet pipes of the tank for preparing the diluted solution of the obtained complex mineral fertilizer is connected to the second outlet of the second ion-exchange unit, the other inlet pipe of this tank and the inlet pipe of the storage tank for demineralized water are connected to the outlet pipe of the desalination apparatus for demineralized water with the possibility of controlling the flow ratio fed into these containers. The presence of the first of these tanks allows directly in the installation to obtain a complex fertilizer solution with a concentration necessary for fertigation, and the presence of the second tank - to have a supply of fresh water for other needs, including for the preparation of salt solutions used during the operation of the plant (simple fertilizers ), as well as for diluting a complex fertilizer solution obtained by the additional output of the installation, which is the output of the nanofiltration side for the concentrate.

In the proposed installation according to the first embodiment, in any of the described and other cases of its implementation, each ion-exchange unit may additionally contain another ion-exchange column, forming a pair with the specified ion-exchange column belonging to this node, with the same ion exchanger filling and having upper and lower drainage devices, respectively , with upper and lower nozzles. In this case, the first and second flow switches are each equipped with a fifth nozzle and are made with the additional possibility of connecting this nozzle to any of the nozzles of a group including the first, second and fourth nozzles, and none of the nozzles of this group can be connected simultaneously with the third and fifth. Moreover, these fifth nozzles of the first and second flow switches are connected, respectively, with the upper and lower nozzles of the aforementioned additionally introduced ion-exchange column.

The use of pairs of columns allows to increase the productivity of the installation almost doubled and make its operation almost continuous. This is achieved due to the fact that it implements not two simultaneously occurring identical processes (in which parallel operations of the same operations would be provided in different columns, as, for example, in one of the particular cases of the installation according to the patent [2]), but different operations in two columns forming a pair.

For the present invention relating to the second embodiment of the installation for processing natural brackish water to produce complex mineral fertilizers, the closest technical solution, as noted above, is also the installation of the patent [3].

This invention, as well as the invention related to the installation according to the first embodiment, is aimed at achieving a technical result consisting in improving the quality of the obtained fertilizer by reducing the content of agrochemically harmful components in it, which are inevitably present in practically used low-grade fertilizers, as well as in increasing the reliability of the installation , including due to improved working conditions of the desalination plant due to the best previous cleaning of the raster supplied to its input ora, and in the prevention of environmentally harmful discharges. During the operation of the proposed installation according to the second embodiment, conditions are created to reduce the consumption of feed fertilizers by bringing together the equivalent amounts of ionic components contained in the feed fertilizers and the resulting complex fertilizer. At the same time, it is possible to obtain an additional amount of complex mineral fertilizer by involving sulfates and carbonates contained in the source of natural water in the processing while preventing the formation of compounds of the corresponding ions with calcium and their ingress into waste solutions. Below, when disclosing the essence of the present invention, other types of achievable technical result can be named.

The proposed installation according to the second embodiment for the processing of natural brackish water to obtain a solution of complex mineral fertilizer, as well as the closest known to it [3], contains a tank for the natural brackish water to be processed, having outlet and inlet pipes, first and second ion-exchange columns having each upper and lower drainage devices, respectively, with upper and lower nozzles, the first and second tanks for regenerating solutions, having each inlet and outlet nozzles, desalinate ny unit having inlet, outlet for desalinated water and the outlet for the salt concentrate. In this case, the first ion exchange column contains cation exchange resin, and the second contains anion exchange resin in the form, respectively, of agrochemically valuable cation and anion components of the resulting complex mineral fertilizer.

To achieve the above technical result, the proposed installation according to the second embodiment, in contrast to the closest known to it, contains the first, second and third ion-exchange units, each of which contains an ion-exchange column having upper and lower drainage devices, respectively, with upper and lower branch pipes. Each ion-exchange unit also contains a container for a regenerating solution, having an outlet pipe and an inlet pipe, which is the first input of the ion-exchange unit and is designed to supply a regenerating solution to it, and an auxiliary tank having an inlet and outlet pipe, as well as the first, second and third switches streams. Moreover, the first and second flow switches each have four nozzles and are configured to connect the third nozzle to the first, second or fourth. The third nozzles of the first and second flow switches are connected, respectively, with the upper and lower nozzles of the ion exchange column. The third flow switch has three nozzles and is configured to connect the third nozzle to the first or second. Moreover, its first and second nozzles are connected, respectively, with the outlet nozzle of the tank for the regenerating solution and the outlet nozzle of the auxiliary tank. The third nozzle of this flow switch is connected to the first nozzle of the second flow switch, and the fourth nozzle of the latter is connected to the inlet of the auxiliary tank. The second branch pipe of the first flow switch is the second input of the ion-exchange unit, which is designed to supply the solution processed in the ion-exchange column. The first branch pipe of the first flow switch is the first output of the ion exchange unit, which is designed to remove the regenerate from the ion exchange column. The fourth branch pipe of the first flow switch forms the third exit of the ion-exchange unit, which is designed to remove the processed solution displaced from the free volume of the ion-exchange column. The second branch pipe of the second flow switch is the second output of the ion-exchange unit, which is designed to remove the solution processed in the ion-exchange column. In this case, the ion-exchange columns of the first and second ion-exchange units are, respectively, the indicated first and second ion-exchange columns, and the capacities of these ion-exchange units for regenerating solutions are, respectively, the indicated first and second containers for regenerating solutions. The ion-exchange column of the third ion-exchange unit contains cation exchange resin in the form of an agrochemically valuable cationic component of the resulting complex mineral fertilizer, and the capacity for the regenerating solution in this ion-exchange unit has an additional inlet pipe, which is the third inlet of this ion-exchange unit, which is designed to supply a salt solution containing an agrochemically valuable cationic component of the resulting complex mineral fertilizer. The installation according to the second embodiment also contains an intermediate tank having two inlet nozzles and an outlet nozzle. The second input of the third ion-exchange unit is connected to the outlet pipe of the tank for the natural brackish water to be processed, the second output of this ion-exchange unit is connected to the second input of the first ion-exchange unit, the first output of which is connected to the first input of the third ion-exchange unit. The first input of the first ion-exchange unit is connected to the outlet pipe of the desalination apparatus for salt concentrate. The first input of the second ion-exchange unit is designed to supply a salt solution containing an agrochemically valuable anionic component of the resulting complex mineral fertilizer, and its second output is the output of the specified installation for the resulting solution of complex mineral fertilizer. The installation according to the second embodiment is also equipped with a nanofiltration unit for separating substances with singly charged anions and substances with multiply charged anions, having an inlet pipe connected to the second output of the first ion-exchange unit, an outlet pipe for permeate and an outlet pipe for concentrate, which is an additional outlet of the specified solution installation the resulting complex mineral fertilizer. The outlet pipe for the permeate of the nanofiltration unit is connected to the inlet pipe of the desalination apparatus and one of the inlet pipes of the intermediate tank with the ability to control the ratio of flows arising from this separation of the flow from the outlet pipe of the nanofiltration unit for permeate. The third output of the second ion-exchange unit is connected to another inlet pipe of the intermediate tank, and the second input of the second ion-exchange unit is connected to the output pipe of the intermediate tank. The third exits of the first and third ion-exchange units are connected to the inlet pipes of the tank for the natural brackish water to be processed, and the first exits of the second and third ion-exchange units are the outputs of the indicated installation for waste solutions.

In addition to the above about the features of the proposed installation according to the first embodiment and their effect on the performance of the technical result, which are also inherent to the installation according to the second embodiment, the latter has a feature consisting in the presence of auxiliary capacitance and a third flow switch in each ion-exchange unit. This allows you to save the regeneration solution displaced from the free volume of the ion exchange columns in a separate container without mixing it with the solution supplied from the outside, located in the tank intended for it. This ensures greater stability of the properties of the regenerating solution.

In the particular case, the capacity for the regenerating solution in the first ion-exchange unit of the proposed installation according to the second embodiment can be equipped with an additional inlet pipe forming the third input of this ion-exchange unit, which is designed to supply an additional component of the regenerating solution for the ion-exchange column of this ion-exchange unit. Such a component is a salt solution that is cleaner in impurity content compared to the salt (simple fertilizer) used in the solution supplied to the third input of the third ion-exchange unit. The supply of such an additional component compensates for the loss of a (insignificant) amount of salt carried out with demineralized water.

In the proposed installation according to the second embodiment, the desalination apparatus can be configured to implement any desalination method from the group including electrodialysis, reverse osmosis method, thermodistillation method, and also cold distillation methods — the vaporization method and the method of capacitive distillation.

As cation exchange resin and anion exchange resin in columns of ion-exchange units, it is preferable to use, respectively, strongly acid sulfocationite and strongly basic anion exchange resin with quaternary ammonium bases. Such cation exchangers and anion exchangers are the most stable and durable, and when used, a large number of sorption-regeneration cycles are permissible. In addition, their use does not lead to the formation of specific complexes that require application in the regeneration of acids or alkalis, which allows salt regeneration to be dispensed with.

In the proposed installation according to the second embodiment, each of the following compounds: a second inlet of a third ion-exchange unit with an outlet pipe of a container for water to be treated, an outlet pipe of a desalination apparatus for salt concentrate with a first input of a first ion-exchange unit, an outlet pipe of an intermediate tank with a second input of a second ion-exchange unit and the third nozzle of the third flow switch with the first nozzle of the second flow switch in each ion-exchange unit - can be implemented containing pump. This allows you to adjust the flow rate regardless of the relative position of the ion-exchange columns and containers used.

To obtain products that are waste, in an easily recyclable form, the installation may additionally contain a vacuum crystallization apparatus and a container for waste solutions having inlet and outlet pipes. In this case, the vacuum crystallization apparatus is connected at its inlet to the outlet pipe of the indicated capacity, and the inlet pipes of this tank are connected to the first outputs of the second and third ion-exchange units.

The installation according to the second embodiment may further comprise a container for preparing a dilute solution of the obtained complex mineral fertilizer having an outlet and inlet nozzles, and a storage tank for demineralized water having an inlet and outlet nozzles. In this case, one of the inlet pipes of the tank for preparing the diluted solution of the obtained complex mineral fertilizer is connected to the second outlet of the second ion-exchange unit, the other inlet pipe of this tank and the inlet pipe of the storage tank for demineralized water are connected to the outlet pipe of the desalination apparatus for demineralized water with the possibility of controlling the flow ratio fed into these containers. The presence of the first of these tanks allows directly in the installation to obtain a complex fertilizer solution with a concentration necessary for fertigation, and the presence of the second tank - to have a supply of fresh water for other needs, including for the preparation of salt solutions used during the operation of the plant (simple fertilizers ), as well as for diluting a complex fertilizer solution obtained by the additional output of the installation, which is the output of the nanofiltration side for the concentrate.

In the proposed installation according to the second embodiment, in any of the described and other cases of its implementation, each ion-exchange unit may additionally contain another ion-exchange column, forming a pair with the specified ion-exchange column belonging to this node, with the same ion exchanger filling and having upper and lower drainage devices, respectively , with upper and lower nozzles. In this case, the first and second flow switches are each equipped with a fifth nozzle and are made with the additional possibility of connecting this nozzle to any of the nozzles of a group including the first, second and fourth nozzles, and none of the nozzles of this group can be connected simultaneously with the third and fifth. Moreover, these fifth nozzles of the first and second flow switches are connected, respectively, with the upper and lower nozzles of the aforementioned additionally introduced ion-exchange column.

The use of pairs of columns allows not only to increase the productivity of the installation almost twice, but also to make its work almost continuous. This is achieved due to the fact that it implements not two simultaneously occurring identical processes (in which parallel operations of the same operations would be provided in different columns, as, for example, in one of the particular cases of the installation according to the patent [2]), but different operations in two columns forming a pair.

The invention is illustrated by the drawings of FIG. 1 - FIG. 9 and the following examples of the implementation of the proposed method using the proposed installation for both options.

FIG. 1 and FIG. 2 are simplified diagrams explaining the passage of streams of natural brackish water and other solutions when implementing the proposed method using, respectively, three ion-exchange columns and three pairs of such columns.

In FIG. 3 and 4 show the distribution of components in ion-exchange columns in a stationary mode of operation.

In FIG. 5, 6 are diagrams of the proposed installation according to the first embodiment, containing, respectively, three ion-exchange columns and three pairs of such columns.

In FIG. 7, 8 are diagrams of the proposed installation according to the second embodiment, containing, respectively, three ion-exchange columns and three pairs of such columns.

In FIG. 9 shows examples of possible implementations of the flow switches used in the proposed installation for both options.

In FIG. 1, the designations K1, K2 and K3 correspond to the first, second and third ion-exchange columns, OPR - desalination apparatus, NF - nanofiltration unit, E1 - tanks for collecting salt concentrate obtained by desalination. The solid lines show the direction of flow during the sequential transmission of natural brackish water and intermediate solutions for its processing through ion-exchange columns, with dashed lines during the regeneration of ion exchangers in the columns. The dashed line also shows the mentioned capacity E1 for salt concentrate from a desalination apparatus used as a regenerating solution.

At the preparatory stage, prior to the implementation of the proposed method in the installation for its implementation, containing three ion-exchange columns, the cation exchange resin in the third column K3 (located, for example, in the original Na-form) is partially converted into the form of an agrochemically valuable cation (for example, potassium) using concentrated salt solution (for example, potassium chloride) which is used as a low-grade simple fertilizer containing impurities, including calcium, iron salts and other components that interfere with desalination and form precipitation with agrochemically valuable cations, for example, with sulfate or hydrophosphate. Such a partial translation is carried out by passing the concentrated fertilizer solution in the direction from the bottom up, feeding it to the K3 column through its lower pipe along lines 17 and 18 until the potassium ions slip through to its outlet (in this case, through the upper pipe). Since the front of the exchange of potassium and sodium has a certain length, the upper part of the cation exchanger layer in the column remains in the form mixed with the original one.

The cation exchange resin in the first K1 column at the described preparatory stage is transferred (in the case considered here as an example) to the K-form with a solution of pure potassium chloride, which is passed through the K1 column from the bottom up, feeding it along lines 14 and 15 through the lower pipe branch of the column. The solution exiting the K1 column is sent along lines 16, 18 in addition to the fertilizer solution supplied via line 17, to the regeneration of cation exchanger in the third K3 column, continuing it until the potassium ions slip into its outlet (in this case, through the upper pipe). Thus, the amount of potassium chloride that is treated with the K1 column is not related to the leakage of potassium ions through this column. In the course of the described regeneration of the cation exchange columns K1, K3, a concentrated solution of sodium chloride leaves through the upper branch pipe of the K3 column and then along line 19.

The anion exchange resin in column K2 (located, for example, in the initial Cl form) at the described preparatory stage is partially converted into the form of an agrochemically valuable anion (e.g. sulfate) using a concentrated solution of low-grade fertilizer or low-grade mineral salt (e.g. sodium sulfate). Such a transfer is carried out by passing through a column K2 a concentrated solution of the fertilizer or salt used in the direction from the bottom up, feeding them along line 20 through the lower pipe of the column K2. The transmission is carried out until the sulfate ions pass through to the column outlet (in this case, its upper branch pipe). Since the front of the exchange of sulfate and chloride has a certain length, the upper part of the anion exchange layer in the K2 column remains in the form mixed with the initial one. During the treatment of the column with anion exchange resin, a concentrated sodium chloride solution also leaves through its upper pipe and then through line 21.

Similarly carry out the operation of regeneration of cation exchange resin and anion exchange resin in columns K3, K1 and K2 in a stationary operating mode. At the same time, as in the preparatory stage, the ion exchangers in the upper parts of the columns remain in mixed ionic forms, and during the implementation of ion exchange in the process of implementing the proposed method, only their lower parts "work".

Fulfillment of the conditions of the method according to which the regenerating solution is fed into the column during the time until a breakthrough occurs at the exit of the third or second column of the corresponding agrochemically valuable ion, and the sequential transmission of natural brackish water and intermediate solutions of its processing is performed for a time until the breakthrough occurs at the exit of the first or a second ion-exchange column of agrochemically harmful ionic components contained in natural brackish water or used simple and (or) low-grade fertilizers are provided by controlling the composition of the solution emerging from the corresponding columns.

In this case, a breakdown of an agrochemically valuable component can be considered, for example, to achieve a concentration at the column exit of more than 2% of the concentration in the initial regenerating solution, and a breakthrough of harmful impurities when passing natural brackish water and intermediate solutions of its processing to achieve a concentration of the least sorbed component of harmful impurities at the outlet of the column, more than 10% of its initial concentration in the solution entering the input of the corresponding column.

программе.The duration of time intervals before such breakthroughs can be determined at the stage of setting up the process when working with specific types of simple fertilizers used, and later, in a stationary operating mode, operations can be controlled, for example, by

the program.

This remark also applies to all the following special cases of the implementation of the proposed method.

Concentrated solutions leaving the K3 and K2 columns during regeneration (sodium chloride in the example under consideration, and, in general, mixed salt solutions) along lines 19 and 21 can be combined and disposed of, for example, by supplying the combined solution through line 26 to shown in the drawing is a vacuum crystallization apparatus and receiving after processing in it a suspension and water.

During the sequential transmission of natural brackish water and intermediate solutions for its processing in a stationary operating mode, which occurs after several cycles of the method are implemented, the cation exchange resin in columns K1 and K3 is mainly in the form of an agrochemically valuable cation of the obtained complex fertilizer (for example, in K-form ), and the anion exchange resin in the K2 column is predominantly in the form of an agrochemically valuable anion of the obtained complex fertilizer (for example, in the form of sulfate).

The source of brackish water is supplied from a tank not shown in the drawing along line 10.1 to the third ion exchange column K3 through its upper pipe. The intermediate solution of processing natural brackish water emerging from this column through its lower pipe is fed via line 33 to the first ion-exchange column K1 through its upper pipe. The flow of the intermediate solution leaving this column through its lower branch pipe, which is the result of further processing of natural brackish water, is fed through line 40 to the nanofiltration unit of the NF unit. The flow of permeate obtained after nanofiltration (from the output of the NF block exiting the drawing) is divided into two parts. One of them is fed through line 7 to the second ion-exchange column K2 through its upper branch pipe, and the other part is sent via line 9 to the ODP desalination unit.

The salt concentrate obtained by desalination and collected in the tank E1 shown in dashed lines, into which it enters via line 13, is subsequently used, as described above, for the regeneration of cation exchange resin in columns K1 and K3.

The solution leaving the second column K2 through its lower pipe, which contains both of the mentioned agrochemically valuable ions (for example, potassium sulfate) as a result of ion exchange in this column, is fed through line 6. It can be used for mixing with demineralized water coming from desalination apparatus ODA through line 11, and the result of mixing, carried out to ensure the required concentration, can be submitted through line 12 for further use during irrigation.

The stream of the concentrate obtained after nanofiltration (from the right side of the drawing of the NF block), containing an agrochemically valuable cationic component and also a complex mineral fertilizer (in this case, containing, along with the specified cationic component, also a sulfate anion and (or) carbonate anion ), served on the output of the process on line 41.

The amount of anion exchange resin in the K2 column and the fraction of the flow of the potassium chloride solution sent to the K2 column after nanofiltration during the adjustment of the process is selected so that the time before the breakthrough of impurity cations through the lower pipe of the K1 column and chloride through the lower pipe of the K2 column is the same, and Further, when implementing the method in a stationary operating mode, the operation of passing natural brackish water and intermediate solutions of its processing through the columns is performed during this time. It is advisable to repeat the described process setting during the transition to a new batch of used source fertilizers.

Upon completion of the operation of passing natural brackish water and intermediate solutions of its processing through columns K1, K3 with cation exchange resin, the upper (large) part of the system formed by these columns is in mixed form, equilibrium with the original natural brackish water, and the lower part is in a mixed front form exchange with potassium ion. Similarly, after the stage of passing the intermediate solution of potassium chloride through the K2 column with anion exchange resin, the upper (large) part of the layer will be in chloride form, equilibrium with the intermediate diluted solution of potassium chloride, and the lower part will be in the mixed form of the exchange front with sulfate ion.

The foregoing about the distribution of components in ion-exchange columns in a stationary mode of their operation is illustrated in FIG. 3 and FIG. 4 relating, respectively, to the system of columns K3, K1 and column K2. The same figures apply to the implementation of the proposed method using the three pairs of columns in FIG. 2. The left parts of both figures 3, 4 relate to the operation of transmitting natural brackish water and intermediate solutions of its processing (sorption stage), and the right ones to ionite regeneration operations (ionite processing stage). In these figures, the following notation:

103 - natural brackish water supplied to the K3 column;

101 - regenerating solution supplied to the column K1;

102 - an intermediate solution of the processing of natural brackish water supplied to the column K2;

104 - regenerating solution supplied to the column K2;

I - zones in cationic form, equilibrium with natural brackish water or an intermediate solution of its processing at the sorption stage;

II - zone of the front of exchange at the stage of sorption;

III - zone in the cationic form of the resulting fertilizer;

IV - zone of the front of exchange at the stage of regeneration;

V - zones of cation exchanger layers exhibiting full exchange capacity in each cycle;

VI - zone in anionic form, equilibrium with an intermediate solution of natural brackish water processing at the sorption stage;

VII - zone in the anionic form of the obtained fertilizer;

VIII - the zone of the anion exchange layer, exhibiting the full exchange capacity in each cycle.

The implementation of the proposed method using three pairs of ion exchange columns is illustrated by the scheme of FIG. 2. The designations in this figure are the same as those in FIG. 1, with the exception of the numbers of ion-exchange columns: the first digit (1, 2 or 3) means the pair number (corresponding to the column number in Fig. 1), and the second (1 or 2) - column number in this pair; the tank for saline concentrate obtained by desalination, shown by the dashed line, also has a two-digit designation E11. The process of implementing the method of FIG. 2 differs from that illustrated in FIG. 1 by the fact that ionite regeneration operations (which, as in FIG. 1, correspond to dashed lines) and sequential transmission of natural brackish water and intermediate solutions for its processing (solid lines correspond to them, as in FIG. 1) are performed simultaneously: shown in FIG. 2 half-cycles - respectively, in columns with odd and even numbers. In each subsequent half-cycle, the columns change roles.

Suppose, for example, that in the current working half-cycle in columns K32 and K12, cation exchange resin is in potassium form, and the anion exchange resin in column K22 is in nitrate form, and these columns are involved in the sequential transmission of the original natural brackish water and intermediate solutions for its processing. These columns were converted (“charged”) to the indicated ionic forms in the previous working half cycle, for example, K32 column - by “charging” with a simple potassium fertilizer solution, K12 column by “charging” a solution of pure potassium chloride, and K22 column by processing it ammonium nitrate solution. The initial solution of natural brackish water is supplied through line 10.1, passes through the K32 column in a top-down direction, the outgoing solution, mainly containing potassium cations, passes through line 33 further from top to bottom through a K12 column. The stream emerging from it, which is a solution that does not contain any cations other than potassium, is sent for nanofiltration to the NF block. After nanofiltration, the permeate stream (from the output of the NF block output, which is the top one in the drawing) is divided into two parts. One part along line 7 enters the K22 column and passes through it from top to bottom. The second part passes through line 9 to the ODP desalination apparatus, after which desalted water (line 11) and salt concentrate (line 13) are obtained. The latter, through the E11 container in which it is collected, and then through line 15 returns to the regeneration (“charging”) of the K11 column, and then (along lines 16, 18) of the K31 column to convert the cation exchange resin in these columns to potassium form.

In the aforementioned first part of the permeate stream leaving the nanofiltration unit NF that passed through the K22 column, all anions in the solution are replaced by nitrate ions, and as a result, a potassium nitrate solution leaves the K22 column through line 6. It can be supplied further along line 12 and be used as a mother liquor for fertigation (without dilution or with dilution with demineralized water leaving the ODA desalination unit via line 11, depending on the agricultural requirements). The concentrate obtained after nanofiltration (from the right side of the drawing of the NF block output) is fed via line 41 to the additional process output as a mineral fertilizer containing sulfate and (or) carbonate anions and the same agrochemically valuable cationic component as in the solution at the column outlet K22.

In the same working half cycle, K31, K11 and K21 columns are simultaneously involved in regeneration (“charging”) operations with concentrated solutions, in all cases from the bottom up. A significant part of the pure potassium chloride is not lost, since it is returned in the form of salt concentrate from the ODA desalination unit to the regeneration of the K11 column through line 13 with a capacity of E11 and line 15. Losses of potassium chloride can only be associated with the fact that an insignificant part of it remains desalted water. In this case, such losses can be compensated by the addition of the same concentrated, freshly prepared solution of pure potassium chloride supplied via line 14 in small amounts. The mixed solution enters line 15 into the K11 column, converting the cation exchanger therein mainly to the K-form. The regenerate leaving the K11 column is sent to the K31 column through line 16 to “charge” it. In addition to it, a solution of simple potassium fertilizer is supplied via line 17. The flows of both of these solutions are combined and enter the K31 column through line 18. The amount of potassium in the fertilizer solution supplied through line 17 is equivalent to the amount of nitrate in the nitrate fertilizer solution, which is fed through line 20 to the K21 column for its regeneration.

After passing through the appropriate columns, the concentrated waste solutions obtained during regeneration (regenerates leaving the K31 column through line 19, and after the K21 column through line 21) are mixed and can be used, for example, as refrigerants or as anti-icing preparations. If it is not possible to directly use the specified mixed concentrated solution can be fed via line 26 to a vacuum crystallization apparatus not shown in the drawing and processed in it to obtain mixed salts in solid form for subsequent disposal or disposal.

The flow rates are selected so that the sequential transmission of natural brackish water and intermediate solutions of its processing to produce a solution of chlorine-free fertilizer and parallel column regeneration with concentrated solutions to convert the ion exchangers into the desired ionic forms are completed simultaneously.

In the next working half-cycle, K31, K11 and K21 columns will be involved in the sequential transmission of natural brackish water and intermediate solutions for its processing, and K32, K12 and K22 columns will be used in the recovery (“charging”) operations with concentrated solutions. Then, cycles containing two described sequential half-cycles are repeated with the described alternation for all operations.

The duration of each half-cycle, on the one hand, is determined by the “slip” of the harmful components contained in the solution-ion exchanger systems into the resulting chlorine-free fertilizer final solution and the intermediate solution directed to nanofiltration. On the other hand, the duration of each working half-cycle is determined by the completion of the conversion of the ion exchanger in the columns into the corresponding ionic forms.

The conversion of the entire charge of ion exchanger in each column into the desired ionic form during the appropriate operations would be associated with the need to process them repeatedly with excessive amounts of salts (as is the case, for example, in countercurrent ion-exchange water treatment processes, where the equivalent cost of the reactants for regeneration is 2- 3 times the corresponding amounts of components removed from the treated water [6]). This would require passing through the columns of excess quantities of agrochemically valuable components and their loss together with mixed solutions discharged along line 26. Therefore, in the proposed method, the duration of the regeneration operations is determined, as described above, by the time before the “breakthrough” of valuable components, for example, potassium or nitrate through the columns during the treatment of the ion exchangers with appropriate concentrated solutions, that is, in each working half-cycle, the regeneration of ion exchangers (transfer to their desired ionic form, or "charge ka ") is incomplete.

It was not known whether, under such conditions, it is possible to carry out repetitive work cycles, and if possible, what proportion of the charge of ion exchangers will “work” in ion exchange processes. The authors of the proposed inventions, it was found that starting from the third working cycle occurs stationary mode, and the cycles begin to completely coincide with each other. Moreover, as shown in FIG. 3, the bottom of the layer in the system of columns with cation exchange resin (zone II) after the stage of passing natural brackish water and an intermediate solution of its processing (position 103) is in mixed ionic form, determined by the exchange front of the cations of this water with an agrochemically valuable component contained in the regenerating concentrated solution and the top (zone IV) after the regeneration stage (the supply of the regenerating solution is shown at 101) is in a mixed form determined by the front of exchange with potassium cations from the composition of the feeds to these columns are diluted solutions (starting with the composition of natural brackish water fed to the column K31 or K32). Only the middle part of the total layer (zone V, the boundaries of which pass through the middle of the exchange fronts) is involved in ion exchange processes, but the fraction of this zone in the ion exchange layer in each of the columns is significant (not less than 70% of the total layer). The equivalent amounts of salts supplied for regeneration in the corresponding solutions are equal to the capacities of these middle zones and are strictly equal to the equivalent amounts of potassium or nitrate in the intermediate and final solutions leaving these columns in the operation of passing through brackish water and intermediate solutions of its processing (but do not exceed them). Thus, in a stationary mode, a "self-sustaining" process of ion-exchange sorption-regeneration is created.

A similar pattern is observed in columns with anion exchange resin K21, K22, as shown in FIG. 4, where the position 102 corresponds to the supply to these columns of an intermediate solution of natural brackish water processing in the form of permeate, and the position 104 to the supply of the regenerating solution to the columns K21, K22.

In the implementation of nanofiltration for the separation of substances containing singly charged anions and substances containing singly charged anions, well-known principles can be used (see, for example: Tverskoy V.A. Membrane separation processes. Polymer membranes. M, Moscow Institute of Chemical Technology named after M.V. Lomonosov, 2008, 59 S. [7]).

As a method of desalination in the desalination apparatus of the ODA (Fig. 1, Fig. 2), you can use any of the well-known industrial methods, including electrodialysis, reverse osmosis or thermal distillation. In the future, it is possible to use cold distillation - vaporization, capacitive distillation and other methods, after developing them to the level of industrial methods.

It is advisable to use a desalination apparatus made according to a two-stage scheme (in which the concentrate of the first stage is fed into the second stage as a processed solution, and the permeate of the second stage is returned to the input of the first stage) or according to a scheme containing more than two stages.

In a real technological process, as will be demonstrated below in the examples of the proposed method, at the beginning of each working half-cycle in the free volumes of each column (in the porous space between the grains, as well as volumes below and above the ion exchanger layer), solutions from the previous operation performed in this column remain .

So, at the beginning of the regeneration operation, when a concentrated solution is passed through the column from bottom to top, a diluted solution comes out from the top pipe of this column, similar in composition to that which was supplied to the column during the sequential transmission of natural brackish water and intermediate solutions for its processing, although not identical him completely, since the process was carried out on an incompletely regenerated column. A similar situation occurs with concentrated solutions exiting through the lower pipe of each column when a corresponding diluted solution (natural brackish water or intermediate solutions for its processing) is fed into it from above after the previous regeneration operation.

It is advisable to displace such solutions remaining from the previous operation from the free volume of the columns into the containers intended for them and use them in the next operation where a similar solution is necessary by supplying the previously displaced solution at the beginning of such an operation to the corresponding column. The solutions remaining in the free volume of the cation exchange columns before their regeneration can be displaced directly into the container from which natural brackish water is supplied, and the solution remaining in the anion exchange column, which differs more significantly in composition from the used brackish water, into a separate intermediate container for subsequent use in the next operation of sequential transmission of natural brackish water and intermediate solutions for its processing. Solutions displaced from the free volume of the columns after incomplete regeneration can also be collected in separate auxiliary containers and used in the next regeneration operation, feeding it to the corresponding column at the beginning of this operation.

Said on the use of regenerating solutions remaining in the columns from previous operations, relates to the implementation of the proposed method as in the scheme of FIG. 1, i.e. using three columns, and according to the scheme of FIG. 2, i.e. using three pairs of columns, with the difference that in the case of only three columns, the solution displaced from the column is used in it, and in the case of three pairs of columns in another column of the pair.

The practical implementation of the use of solutions remaining in the columns from previous operations will be explained in more detail when considering two embodiments of the proposed installation for implementing the proposed method (respectively, Fig. 5, 6 and Fig. 7, 8) and examples.

In FIG. 5 shows a diagram of the proposed installation according to the first embodiment for implementing the method of processing natural brackish water to obtain solutions of complex mineral fertilizers. This diagram corresponds to the proposed method, illustrated by the diagram of FIG. 1, i.e. using only three ion exchange columns. In contrast to the circuit of FIG. 1, in FIG. 5 shows flow controls, pumps, tanks, and other equipment. All designations present in FIG. 1 are also used in FIG. 5 and have the same meaning with them.

The installation of FIG. 5 includes three identical ion-exchange units U1, U2, U3, capacity E10 for natural brackish water to be processed, nanofiltration unit NF, desalination apparatus OPR, capacity E5 for preparing a solution of the obtained fertilizer, storage capacity E8 for demineralized water obtained in excess of the required volume for the preparation of a dilute solution of a complex mineral fertilizer, an E20 tank for waste solutions (ion exchange column regenerates), as well as an E6 intermediate tank, the use of which is ilos above and which will be further explained below. The composition of the installation according to the first option under consideration may also include a vacuum crystallization apparatus SRS,

Each ion-exchange unit contains an ion-exchange column (K1, K2 or K3) and a container (E1, E2 or E3) for the regenerating solution, the numerical designations of which correspond to the designation of the unit.

As the ion exchanger, the K3 and K1 columns of nodes U3 and U1 contain strongly acid sulfocationionite, and the K2 column of node U2 contains strongly basic anion exchange resin with quaternary ammonium bases. Columns K1 and K3 contain cation exchange resin in a mixed form - the initial and cationic component of the obtained complex fertilizer, and column K2 - anion exchange resin in a mixed form - the initial and anionic component of this fertilizer.

Each ion-exchange unit contains two flow switches P with a digital designation in the form of the number of the ion-exchange unit (first digit) and the numbers 1 or 2 of the switch in this unit (second digit). Each flow switch has four nozzles having designations 1, 2, 3 and 4. The above designations of the nozzles (1, 2, 3, 4) in the diagram are the same for all switches of the three nodes U1, U2, U3 and therefore in the rest of the text where necessary, they are used only in conjunction with the indication of the assembly and switch to which these pipes belong. The same applies to the designations (1, 2, 3) of the inputs and outputs of ion-exchange units.

Each of the switches is configured to connect its third pipe either to the first, or to the second, or to the fourth. It is easy to see that flow switches with this function can be implemented using simple valves that can be either open or closed (see Fig. 9, which shows examples of the possible implementation of flow switches of all kinds used in this and other cases perform the proposed installation).

As already noted above, when disclosing the essence of the inventions, the given functional characteristic of the flow switches does not exclude the possibility of finding any of them in a “closed” state in which there is no connection between the nozzles. This also applies to all flow switches described hereinafter.

Flow switches with even numbers (lower in the drawing in each ion-exchange unit) are connected by their third nozzles to the lower nozzles of ion-exchange columns, and flow switches with odd numbers (upper in the drawing) are connected by third nozzles to the upper nozzles of ion-exchange columns of those nodes in which they are composed come in. The first branch pipe of each of the even-numbered switches is connected to the outlet pipe of the container for the regenerating solution included in this ion-exchange unit (in the case shown in the drawing, line 15 with pump H1, line 22 with pump H2, line 18 with pump H3, respectively, for containers E1, E2, E3 nodes U1, U2, U3).

One of the inlet pipes of the said container is the first input (Bx.1) of the ion-exchange unit, intended for supplying a regenerating solution. For anion exchange column K2 of node U2, such a solution is supplied externally via line 20, and for cation exchange columns K3 and K1 of nodes U3, U1, the supply of a regenerating solution will be described below. The second input of the node (Bx.2) is the second pipe of the flow switch upper in the drawing. It is designed to supply natural brackish water or intermediate solutions of its processing to the ion-exchange unit.

Each ion-exchange unit has the first and second outputs: Output 1 and Output 2, which are, respectively, the first pipe of the upper and second pipe of the lower flow switches according to the drawing. The first output is designed to remove the regeneration of the ion-exchange column, and the second - to remove the solution processed in the ion-exchange column.

Salt concentrate from the outlet of the OPR desalination apparatus, which is the main component of the regenerating solution for the column K1 of the first node U1, is fed to its first input Bx.1 via line 13 containing the pump H5. The regenerate from the K1 column, which is the main component of the regenerating solution for the K3 column of node U3, is fed to the first input Bx.1 of this node from the first output of Exit 1 of node U1 via line 16. Additional components of the regenerating solutions for these columns (respectively, a solution of pure salt containing the cationic component of the obtained complex fertilizer, and a solution of the used low-grade fertilizer containing the same cationic component, for the column K1 of the first node U1 and the column K3 of the third node U3) are fed to the third ode INP3 nodes U1 and U3 on lines 14 and 17, respectively. These inputs, as well as the first inputs, are the inlet pipes of the tanks E1 and E3.

A solution of a simple low-grade fertilizer containing the anionic component of the resulting complex fertilizer is used as a regenerating solution for the K2 column of node U2. Such a solution is supplied via line 20 to the first input Bx. 1 ion-exchange node U2, which is the inlet of the tank E2.

The regenerates of the columns K3 and K2, respectively, of the nodes U3 and U2, which are waste solutions, from the first outputs Out.1 of these nodes along lines 19 and 21 are fed into the tank E20 through its inlet pipes.

The second input V2 of node U3 is connected by a line 10.1 containing the pump H4 to the outlet pipe of the tank E10 for the natural brackish water to be processed, which is supplied to this tank through line 10. The second input V2 of node U1 is connected by line 33 to the second output of Vy.2 node U3.

In each ion-exchange unit, the fourth branch pipe of the flow switch, which is the upper one in the drawing, forms the third output Out.3. The third output of the node U1 is connected by line 16.1 to one of the inlet pipes of the tank E10 for the natural brackish water to be processed, and the third output of the third node U3 is connected to another input pipe of the same tank by the line 19.1.

The second output of the Output 2 node U1 line 40 is connected to the input of the nanofiltration unit NF. The output of this block for permeate (the upper one according to the drawing) is connected by lines 7 and 9, respectively, with one of the inlet pipes of the intermediate tank E6 and the input of the desalination apparatus of the OPR. These lines contain, respectively, valves B1 and B2 for regulating the ratio of flows in these lines. With its other inlet pipe, the said intermediate tank E6 is connected to the third output Vyh.3 of the second ion-exchange unit U2, and the output pipe through line 7.1, which contains the pump H8, is connected to the second input Bx.2 of the same node.

The concentrate obtained after nanofiltration (from the output of the NF unit, right from the drawing), which is an additional stream of complex fertilizer obtained in the plant, is fed to the plant output via line 41.

The second output Exit.2 node U2 is the output for the solution obtained complex fertilizer. As shown in FIG. In the particular case, it is connected by line 6 to one of the inlet pipes of the E5 tank, in which the specified solution is mixed with demineralized water coming from the corresponding output of the ODP desalination unit via line 11 with pump H6 and line 11.1 with valve B4. The latter is used to regulate the concentration of the obtained complex fertilizer before feeding it to irrigation along line 12.

Storage tank E8 for demineralized water is connected to the output of the OPR desalination apparatus by line 11 with a pump H6 and then by line 11.2 with a valve B3. This valve and the previously mentioned valve B4 are used to control the ratio of demineralized water flows supplied to tanks E5 and E8. Desalted water from the storage tank can be used for various purposes, in particular, in the preparation of solutions of fertilizers used (including additional, coming through line 41). An outlet line 11.3 is provided for the selection of such water from the E8 tank.

At the initial stage of the transmission operation of natural brackish water and intermediate solutions for its processing, carried out sequentially in nodes U3, U1, U2, the ion-exchange columns are displaced from the free volume of the exchangeable solution of the regenerating solution supplied to the column, which remained in the columns after the ionite regeneration operation performed before . At the same time, the flow switches that are upper in the drawing are in the state of connecting the nozzles 3 to the nozzles 2, and the lower ones are in the state of connecting the nozzles 3 to the nozzle 4. The crowding out occurs in the tank for the regenerating solution E3, E1, E2, respectively, along lines 3.1, 4.1, 6.1.

The specified initial stage is primarily carried out for the column K3 node U3. After its completion, the second (lower in the drawing) flow switch P32 of the U3 node is transferred to the state of connection of the pipe 3 with pipe 2, the processed solution passing through the column K3 enters the Outlet 2 of the U3, then it goes to input Bx via line 33. 2 nodes U1, and the indicated initial stage for the column K1 of node U1 is carried out. At its end, the second (lower in the drawing) flow switch P12 of node U1 is transferred to the state of connection of pipe 3 with pipe 2, to the output Vykh.2 of node U1 the processed solution passes through column K1.

Further along line 40, it is fed to the input of the nanofiltration unit of the NF. The permeate stream (from the top of the output of this unit in the drawing) branches out into two — along line 9 and along line 7 with the possibility of controlling the ratio of the resulting flows using valves B2 and B1. On line 9, the flow is fed to the input of the OPR desalination apparatus, and on line 7 to the intermediate tank E6 through one of its inlet pipes. The stream from the tank E6 via line 7.1 enters the input Bx.2 of node U2, and the indicated initial stage for the column K2 of this node is carried out. At this stage, the flow switch P21 (upper according to the drawing) of node U2 is in the state of connecting pipe 3 to pipe 2, switch P22 (lower according to the drawing) is in the state of connecting pipe 3 to pipe 4.

At the end of this stage, for the K2 column of node U2, the main stage of the “through” sequential transmission of natural brackish water and intermediate solutions of its processing begins, before which it has already begun for columns K3 and K1, respectively, of nodes U3 and U1.

At this stage, the source water and intermediate solutions for its processing pass along the path: capacity E10 - line 10.1 - input В.2 of node U3 - column K3 - output Output 2 of node U3 - line 33 - input В.2 of node U1 - column K1 - output Output 2 of node U1 - line 40 - input of the nanofiltration unit NF. Next, the permeate from the corresponding output (top according to the drawing) of this block branches into two streams. One of them goes along the path: line 7 - intermediate capacitance E6 - line 7.1 - input Bx.2 of node U2 - column K2 - output Output 2 of node U2 - line 6 onwards (in a particular case, through capacity E5 and line 12) - to the output of the installation.

At the same time, another flow of permeate enters the inlet of the ODP desalination apparatus, and the concentrate from the corresponding output of the nanofiltration unit NF (right in the drawing) flows through line 41 to the installation output for an additional flow of the obtained fertilizer. Desalinated water from the ODS desalination unit, right in the drawing, is supplied to line 11 with desalted water. As shown in FIG. In a particular case, its flow branches into two. One of them enters the E5 tank via line 11.1 for mixing with the result of processing obtained from the output of Exit 2 of the U2 unit via line 6 — a solution of complex fertilizer and diluting this solution until the required concentration is reached, and the other — via line 11.1 to the storage tank E8 for demineralized water. The ratio of these flows is regulated by valves B3 and B4.

During the described execution of the solution transmission operation, all flow switches are in the state of connection of the pipe 3 with the pipe 2.

During the ion exchange regeneration operation, the regenerating solution is supplied to each column from the corresponding tank: to the K3 column from the E3 tank via line 18, to the K1 column from the E1 tank through line 15, to the K2 column from the E2 tank via line 22. the flow switches lower in the drawing are in the state of connection of the pipe 3 with the pipe 1. At the initial stage of this operation, the solution remaining after the previous operation described above is displaced from the free volume of the columns. From the K3 and K1 columns, such a displacement is carried out into the E10 tank for water to be processed through the outlets of Outlets 3 of the U3, U1 nodes and further along the lines 19.1, 16.1, respectively, and from the K2 column through the outlet of Exits 3 of the U2 node through line 21.1 in the intermediate tank E6. In this case, the flow switches that are upper in the drawing are in the state of connection of the pipe 3 with the pipe 4.

At the end of this displacement, a regenerate begins to come out of the columns, which is supplied from the K3 and K2 columns to the E20 tank for waste solutions, respectively: from the K3 column through the output Exit 1 of node U1 along line 19, and from the column K2 through the exit Exit. 1 node U2 on line 21. As for the column K1, regenerate is supplied from it through the output Exit 1 of node U1 via line 16 to input Вх.1 of node U3, from where it enters the tank E3 for the regenerating solution of this node. During the described stage of the operation of the regeneration of ion exchangers, the flow switches that are upper in the drawing are in the state of connection of the pipe 3 with the pipe 1.

In more detail, the operation of the installation considered is described in Example 1 below.

As already mentioned, the installation according to the considered first option may contain a vacuum crystallization apparatus SRS. In this case, the outlet pipe of the container E20 for waste solutions is connected to the inlet of this apparatus, which also has an outlet 24 for solid waste and an outlet 23 for water.

программе. В этом случае формирование и выдача команд таким блоком могут быть осуществлены на основе полученных на этапе наладки процесса данных о продолжительностях операций и их этапов, как это было пояснено выше при описании предлагаемого способа. Если такой режим управления не предусмотрен или не используется, этот блок может быть использован для централизованного управления в "ручном" режиме. Наличие связей блока централизованного управления с управляемыми элементами установки на фиг. 5 показано условно-выходящими из данного блока стрелками.The installation may be provided with a conditionally shown in the diagram of FIG. 5 centralized control unit (BCU). To implement this control, the flow switches must be equipped with electrically controlled actuators connected to the specified unit. With the possibility of such control, pumps, desalination and vacuum-crystallization apparatuses (necessary for this connection in the diagram of Fig. 5 are not shown) must also be made. The specified block can carry out, in particular, automated control by

the program. In this case, the formation and issuance of commands by such a unit can be carried out on the basis of data obtained at the stage of setting up the process on the duration of operations and their stages, as was explained above in the description of the proposed method. If such a control mode is not provided or not used, this unit can be used for centralized control in the "manual" mode. The presence of connections of the centralized control unit with the controlled installation elements in FIG. 5 is shown by arrows conditionally emerging from this block.

The proposed installation according to the first embodiment, in the case when it contains three pairs of ion-exchange columns, is shown in FIG. 6. An additional three columns of the installation of FIG. 6 pairing with the columns of the installation of FIG. 5 are part of the ion-exchange units U1, U2, U3 and have the same design as the columns of the installation of FIG. 5. The same designations are used for columns as in FIG. 2: K11 and K12 - in the node U1, K21 and K22 - in the node U2, K31 and K32 - in the node U3. The rest used in FIG. 2 designations coinciding with the designations in FIG. 6 also have the same meaning with them.

To provide the possibility of using second columns in each ion-exchange unit, the first and second flow switches are changed. Each of them, in comparison with the switches of the circuit of FIG. 5 is equipped with an additional fifth (5) nozzle and is made with the additional possibility of connecting this nozzle to any of the nozzles 1, 2, 4, which is not currently connected to the nozzle 3 (similarly, the nozzle 3 has the ability to connect to any of the nozzles 1, 2 , 4, not currently connected to the pipe 5). Despite the noted higher functional complexity of the first and second flow switches, they are structurally uncomplicated and can be implemented (with proper control, eliminating the possibility of invalid connections), for example, using simple valves, which can be in one of two states: “open” or “ closed". An embodiment of a flow switch with the described function is shown in FIG. 9, which shows the possible implementation of all types of switches used in this and other cases of the proposed installation. The corresponding valve connection diagram is compiled directly from the description of the switch function, which can be implemented otherwise, based on other types of switching elements.

Characterizing at the functional level the first and second switches of the installation flows of FIG. 6 as such (and not with respect to the corresponding switches of the installation of Fig. 5), we can say that they have five nozzles and are configured to connect any of the nozzles of the group including the third and fifth nozzles with any of the nozzles of the group including the first, second and fourth nozzles, and none of the nozzles of one group can be connected simultaneously with two nozzles of the other group. Their structural characteristics can be represented, for example, in the following form. The flow switch contains two groups of three valves, each of which has a first and second nozzle (respectively, the upper and lower according to the drawing of Fig. 9). The first valve branch pipes of the first group connected to each other and the first valve branch pipes of the second group connected to each other form, respectively, the third and fifth switch nozzles. The second nozzles of the first, second and third valves of the first group, connected to the same valves of the second group, form, respectively, the first, fourth and second nozzles of the switch.

For the flow switches in FIG. 6, the same designations are used as in the circuit of FIG. 5: first (upper in the drawing) switches - P11, P21, P31, respectively, for nodes U1, U2, U3: second (lower in the drawing) switches - P12, P22, P32, respectively, for nodes U1, U2, U3.

An additional fifth branch pipe of the flow switches is used in each ion-exchange unit for connection with a column pairing with the column present in the diagram of FIG. 5, namely, the fifth nozzles of the first switches are connected to the upper nozzles of the columns, in the fifth nozzles of the second switches to the lower nozzles of the columns.

Otherwise, the apparatus of FIG. 6 does not differ from the installation of FIG. 5. All others used in FIG. 5 designations are used and in FIG. 6 and have the same meaning with them.

The described features of the installation for implementing the proposed method illustrated in FIG. 6, allow to realize the operation of sequential transmission of natural brackish water and intermediate solutions for its processing and the operation of regeneration of ion exchangers not alternately, but simultaneously. In one half cycle, when the first of these operations is performed using columns K31, K11, K21, the second operation is performed using columns K32, K12, K22, and in the other half cycle, the columns change roles, etc. with a repetition of the distribution of roles of the columns after every two half-cycles.

As a result, the process of producing complex mineral fertilizer is almost continuous, and the installation productivity is doubled compared to the installation of FIG. 5. The insignificant interruptions in the receipt of fertilizer received at the plant exits are associated with the need to displace the regenerating solution remaining from the previous ionite regeneration operation from the free volume of the columns. At the time of such displacement, “through” sequential passage through the columns of three nodes of natural brackish water and intermediate solutions of its processing is interrupted.

To the installation of FIG. 6 applies all of the foregoing to the installation of FIG. 5, regarding the possibility of equipping it with a centralized control unit BTSU.

In FIG. 7 shows the proposed installation according to the second embodiment, corresponding to the circuit of FIG. 1, explaining the proposed method. In contrast to the circuit of FIG. 1, in FIG. 7 shows flow controls, pumps, tanks, and other equipment.

A feature of this installation compared to the installation of the first embodiment, illustrated by the diagram of FIG. 5, is the presence of an auxiliary capacity in each ion-exchange unit (respectively, E12 in the node U1, E22 in the node U2, E32 in the node U3). Therefore, the used container designations for the regenerating solution contained in the installation of the first embodiment, illustrated by the scheme of FIG. 5, in the diagram of FIG. 7 differ from those in the diagram of FIG. 5: respectively, E11 - in the node U1, E21 - in the node U2, E31 - in the node U3.

An auxiliary tank in each node is used to displace the regenerating solution remaining in the free volume of the ion exchange column after the completion of the ion exchange regeneration operation. For this, the inlet pipe of this capacity is connected to the fourth (4) pipe of the second (lower in the drawing) pipe of the flow switch of the corresponding ion-exchange unit (recall that in the installation according to the first embodiment, illustrated in Fig. 6, one was connected to the fourth pipe of the second flow switch from the inlet nozzles of the tank for the regenerating solution).

Due to the presence in each node of two containers for the regenerating solution (one into which such a solution is supplied from the outside of the unit, and the other into which the regenerating solution is displaced from the free volume of the column), each ion-exchange unit is supplemented by a third flow switch (P13, respectively, in the unit U1, P23 - in the node U2, P33 - in the node U3), which allows either to supply the source regenerating solution (from tanks E11, E21, E31) or to return the solution previously displaced from the free volume of the columns (from auxiliary tanks E12, E22, E32). For this, the third flow switch in each ion-exchange unit contains the first (1), second (2) and third (3) nozzles and is configured to connect the third (3) nozzle to the first (1) or second (2). In this case, the third (3) branch pipe of this switch is connected to the first branch pipe (1) of the second flow switch (in the case shown in Fig. 6, line 18 with the pump H3 for the node U3, line 15 with the pump H1 for the node U1, line 22 s pump H2 - for node U2). In one of the states of the third flow switch, an initial regenerating solution from the tank intended for it can be supplied to the ion exchange column through the first (1) nozzle of the second (lower in the drawing) stream, and in another, a solution from the auxiliary tank, for which the outlet pipes of these containers are connected, respectively, with the first (1) and second (2) nozzles of the third flow switch.

Otherwise, the installation diagram of FIG. 7 does not differ from the circuit of FIG. 5 (and from the installation of FIG. 6). Used in FIG. 7 designations matching the designations of FIG. 5 have the same meaning with them.

The operation of the installation according to the second embodiment for implementing the proposed method will be considered for a particular case of its implementation, illustrated by the diagram of FIG. 8, which differs from that described above (Fig. 7) by the presence in each ion-exchange unit not of one but of a pair of columns. The circuit of FIG. 8 corresponds to the circuit of FIG. 2, explaining the proposed method. In contrast to the circuit of FIG. 2, in the diagram of FIG. Figure 8 shows flow controls, pumps, tanks, and other equipment.

An additional three columns of the installation of FIG. 8 pairing with the columns of the installation of FIG. 7 are part of the ion-exchange units U1, U2, U3 and have the same design as the columns of the installation of FIG. 7. The same designations are used for columns as in FIG. 2, explaining the proposed method: K11 and K12 in the node U1, K21 and K22 in the node U2, K31 and K32 in the node U3. The rest used in FIG. 2 designations coinciding with the designations in FIG. 8, have the same meaning with them.

To provide the possibility of using second columns in each ion-exchange unit, the first and second flow switches are changed. Each of them, in comparison with the switches of the circuit of FIG. 7 is equipped with an additional fifth (5) nozzle and is made with the additional possibility of connecting this nozzle to any of the nozzles 1, 2, 4, which is not currently connected to the nozzle 3 (similarly, the nozzle 3 has the ability to connect to any of the nozzles 1, 2 , 4, not currently connected to the pipe 5). A possible embodiment of a flow switch with such a function based on the simplest valves, which can be in open or closed state, is shown in FIG. 9, which shows the possible implementation of all types of switches used in this and other cases of the proposed installation. To the function and possible constructive implementation of the first and second flow switches, all of the above applies to similar installation switches of FIG. 6.

For the flow switches in FIG. 8, the same designations are used as in the circuit of FIG. 7: the first (upper according to the drawing) switches - P11, P21, P31, respectively, for nodes U1, U2, U3: the second (lower according to the drawing) switches - P12, P22, P32, respectively, for nodes U1, U2, U3.

An additional fifth branch pipe of the flow switches is used in each ion-exchange unit for connection with a column pairing with the column present in the diagram of FIG. 7, namely, the fifth nozzles of the first switches are connected to the upper nozzles of the columns, in the fifth nozzles of the second switches to the lower nozzles of the columns.

Otherwise, the apparatus of FIG. 8 does not differ from the installation of FIG. 7 (as well as from the installations of FIG. 5 and FIG. 6). All used in the diagram of FIG. 8 designations that match those used in FIG. 7 (as well as in Fig. 5 and Fig. 6) have the same meaning with them. In this regard, it can be noted that the parts of the proposed installation external to the ion-exchange nodes for implementing the proposed method are the same in both cases in its implementation.

The described features of the installation for implementing the proposed method illustrated in FIG. 8, allow to realize the operation of sequential transmission of natural brackish water and intermediate solutions for its processing and the operation of regeneration of ion exchangers not alternately, but simultaneously. In one half cycle, when the first of these operations is performed using columns K31, K11, K21, the second operation is performed using columns K32, K12, K22, and in the other half cycle, the columns change roles, etc. with a repetition of the distribution of roles of the columns after every two half-cycles.

As a result, the process of obtaining complex mineral fertilizers, as in the installation according to the scheme of FIG. 6 for the first embodiment, it runs almost continuously, and the productivity of the installation doubles compared with the installation of FIG. 7. Insignificant interruptions in the amount of fertilizer received at the plant exits are associated with the need to displace the regenerating solution remaining from the previous ionite regeneration operation from the free volume of the columns. At the time of such displacement, “through” sequential passage through the columns of three nodes of natural brackish water and intermediate solutions of its processing is interrupted.

At the initial stage of the transmission operation of natural brackish water and intermediate solutions for its processing, carried out sequentially in nodes U3, U1, U2, the ion-exchange columns are displaced from the free volume of the exchangeable solution of the regenerating solution supplied to the column, which remained in the columns after the ionite regeneration operation performed before . The displacement takes place in auxiliary tanks E32, E12, E22, respectively, along lines 3.1, 4.1, 6.1 at nodes U3, U1. U2.

In this case, the flow switches that are upper in the drawing are in the state of connecting the nozzles 3 (or 5, depending on which of the columns of the pair the stage in question is carried out) with nozzles 2, and the lower ones are in the state of connecting the nozzles 3 (or 5) with nozzle 4 .

A further description of this given operation is given with reference to its execution in columns K31, K11, K21 left of the drawing of nodes U3, U1, U2. We also note that when describing the state of the flow switches, the nozzles of the same switches used at the same time in the operation of ion exchange regeneration in parallel columns K32, K12, K22, which are right in the drawing, are not indicated. A similar remark applies to the following description of the operation of the regeneration of ion exchangers.

The specified initial stage is primarily carried out for the column K31 node U3. After its completion, the second (lower in the drawing) flow switch P32 of the U3 node is transferred to the connection state of the pipe 3 with pipe 2, the processed solution passing through the column K31 enters the Outlet 2 of the U3, then it goes to input Bx via line 33. 2 nodes U1, and the indicated initial stage for the column K11 of node U1 is carried out. At the end of it, the second (lower in the drawing) flow switch P12 of node U1 is transferred to the state of connection of pipe 3 with pipe 2, to the output Vykh.2 of node U1 the processed solution passes through column K11.

Further along line 40, it is fed to the input of the nanofiltration unit of the NF. The permeate stream (from the top of the output of this unit in the drawing) branches out into two — along line 9 and along line 7 with the possibility of controlling the ratio of the resulting flows using valves B2 and B1. On line 9, the flow is fed to the input of the OPR desalination apparatus, and on line 7 to the intermediate tank E6 through one of its inlet pipes. The stream from the tank E6 via line 7.1 enters the input Bx.2 of node U2, and the indicated initial stage for the column K21 of this node is carried out.

At this stage, the flow switch P21 (upper according to the drawing) of node U2 is in the state of connecting pipe 3 to pipe 2, switch P22 (lower according to the drawing) is in the state of connecting pipe 3 to pipe 4.

At the end of this stage, for the K21 column of node U2, the main stage of the sequential transmission of natural brackish water and intermediate solutions of its processing begins, before which it has already begun for columns K31 and K11, respectively, of nodes U3 and U1.

At this stage, the source water and the intermediate solutions for its processing pass along the path: capacity E10 - line 10.1 - input In.2 of node U3 - column K31 - output Out.2 of node U3 - line 33 - input In.2 of node U1 - column K11 - output Output 2 of node U1 - line 40 - input of the nanofiltration unit NF. Next, the permeate from the corresponding output (top according to the drawing) of this block branches into two streams. One of them goes along the path: line 7 - intermediate capacitance E6 - line 7.1 - input Bx.2 of node U2 - column K2 - output Output 2 of node U2 - line 6 onwards (in a particular case, through capacity E5 and line 12) - to the output of the installation.

At the same time, another flow of permeate enters the inlet of the ODP desalination apparatus, and the concentrate from the corresponding output of the nanofiltration unit NF (right in the drawing) flows through line 41 to the installation output for an additional flow of the obtained fertilizer.

Desalinated water from the ODS desalination unit, right in the drawing, is supplied to line 11 with desalted water. As shown in FIG. In a particular case, its flow branches into two. One of them enters the E5 tank via line 11.1 for mixing with the result of processing obtained from the output of Exit 2 of the U2 unit via line 6 — a solution of complex fertilizer and diluting this solution until the required concentration is reached, and the other — via line 11.1 to the storage tank E8 for demineralized water. The ratio of these flows is regulated by valves B3 and B4.

During the execution of the described transmission of solutions, the first and second flow switches of all ion-exchange units are in the state of connection of the pipe 3 with the pipe 2.

In parallel with the described operation, performed with the participation of left columns according to the drawing, the operation of regeneration of ion exchangers in the right columns according to the drawing is carried out.

At the initial stage of this operation, the solution left over from the free volume of the K32, K12, K22 columns of the solution remaining after passing through the operation of passing natural brackish water and intermediate solutions for its processing (the execution of which is similar to that described above for the left columns K31, K11 , K21).

From the K32 and K12 columns, such a displacement is carried out into the E10 tank for water to be processed through the outlets of Outlets 3 of nodes U3, U1 and further along lines 19.1, 16.1, respectively, and from the K22 column through the outlet of Outlets 3 of U2 nodes along line 21.1 in the intermediate tank E6. In this case, the first (upper drawing) flow switches are in the state of connection of the pipe 5 with the pipe 4.

At this stage, the regenerating solution is supplied to each column from the corresponding auxiliary vessel: to the K32 column - from the E32 tank via line 18, to the K12 column - from the E12 tank through line 15, to the K22 column - from the E22 tank through line 22. The third ones the flow switches are in the state of connection of the pipe 3 to the pipe 2, and the second (lower according to the drawing) - in the state of the connection of the pipe 5 to the pipe 1.

At the end of this displacement, a regenerate starts to come out of the columns, which is supplied from the K32 and K22 columns to the E20 tank for waste solutions, respectively: from the K32 column through the output Exit 1 of node U1 along line 19, and from the column K22 through the exit Exit. 1 node U2 along line 21. As for the K12 column, regenerate is supplied from it through the output Exit 1 of node U1 via line 16 to input Bx.1 of node U3, from where it enters the tank E31 for the regenerating solution of this node. During the described stage of the ion exchange regeneration operation, the first and second flow switches are in the state of connecting the pipe 5 to the pipe 1. In this case, the third flow switches are in the state of connecting the pipe 3 to the pipe 1, i.e. the regenerating solution is supplied not from the auxiliary tank, but from the tank for the regenerating solution (E31, E11, E21 at nodes U3, U1, U2, respectively).

Concentrate is supplied to the container E11 for the regenerating solution of the first node U1 as such a solution from the corresponding outlet (lower in the drawing) of the ODP desalination apparatus through the first input Bx.1 of node U1 along line 13, which contains in FIG. 8 case pump H5. Via line 14, through the third input Bx.3 of node U1, an additional component of the regenerating solution can be supplied in the form of a salt that is purer than the salt contained in the used simple low-grade fertilizer containing the agrochemically valuable component of the obtained complex fertilizer, the solution of which is fed into the tank E31 of the node U3 through its third input Vh.3 on line 17.

The said solution, supplied through line 17, is one of the components of the regenerating solution for the ionite columns of the node U3. The main component of the regenerating solution supplied to the capacity E31 of the U3 node through its first input Bx.1 via line 16 is the column regeneration of the U1 node coming from the first output of the B1.

The regenerating solution for the ion exchanger of the columns of node U2 is supplied to the capacitance E21 of this node through its first input Bx.1 along line 20.

After the completion of both described parallel operations in the group of left columns and the group of right columns, the first half-cycle of the carried out method ends, these groups of columns change roles, and processes similar to those described above and making up the second half-cycle occur in the ion-exchange units and in the external part of the installation ongoing method. Further, the proposed method is carried out in the described installation as a cyclic process with cycles formed by two consecutive half-cycles in which there is a periodic exchange of column roles in each of the pairs of columns that are part of the ion-exchange units.

The operation of the proposed installation according to the second option described above is explained in more detail when considering example 2 of the implementation of the proposed method.

Like the installation according to the first embodiment (Fig. 5, Fig. 6), the installation according to the second embodiment (Fig. 7, Fig. 8) can be equipped with a central control unit of the central control unit. To implement this control, the flow switches must be equipped with electrically controlled actuators connected to the specified unit. With the possibility of such control, pumps, desalination and vacuum-crystallization apparatus must also be made (necessary for this connection in the diagrams of Fig. 7, Fig. 8 are not shown). The specified block can carry out, in particular, automated control by a temporary program. In this case, the formation and issuance of commands by such a node can be carried out on the basis of data obtained at the stage of setting up the process on the duration of operations and their stages, as was explained above in the description of the proposed method. If such a control mode is not provided or not used, this node can be used for centralized control in the "manual" mode. The presence of connections of the centralized control unit with the controlled installation elements in FIG. 7, FIG. 8 is shown by arrows conditionally exiting from this block.

The following descriptions of examples 1 and 2-6 relate to the implementation of the proposed method using the proposed installation according to the first and second options, respectively, in particular cases, according to FIG. 5 and FIG. 8.

Example 1

Use the real brackish underground water delivered to the laboratory with a total salinity of 3.05 g / l (0.3%) and the composition shown in Table 1.

In separate containers (canisters) stocks (10 l each) of the following solutions are prepared:

- 6.8% (70.78 g / l, or 0.95 g-eq / l) of solution No. 1 of potassium chloride of the “pure” qualification in accordance with GOST 4234-77 with a negligible impurity content;

in the preparation of solution No. 1, demineralized water obtained from tap water using a laboratory desalination plant ODA;

- 6.4% (67.45 g / l or 0.95 g-equiv / l) of solution No. 2 from sodium sulfate (technical qualifications of sodium sulfate of technical grade “B” in accordance with GOST 6318-77) with a calcium sulfate content not more than 1% (in solution - 0.02% in accordance with solubility) and iron - 0.03% (in solution - 0.003%);

- 6.8% (70.78 g / l, or 0.95 g-equiv / l) of solution No. 3 from a fertilizer corresponding to the qualification "Granular potassium chloride" GOST 4586-95 with a content of the main component of at least 92% and impurities salts of multiply charged ions up to 3% (up to 0.3% in the prepared solution);

in the preparation of solutions No. 2 and 3, tap water is used.

The prepared solutions are cleaned of solids by filtration through cartridges or a column of quartz sand.

The laboratory setup is assembled according to the circuit shown in FIG. 5, so that solutions No. 1, 2, 3 can be supplied, respectively, along lines 14, 20, 17 in containers E1, E2, E3 through the first inlets (Bx.1) of the ion-exchange units U1, U2, U3.

K3 and K1 are columns equipped with lower and upper drainage devices, with a loading of 2 l of KU-2 strongly acid cation exchanger in Na form with a capacity of 2.3 g-equiv / l. The free volume of the columns (in the porous space between the grains, as well as above the layer and under the layer of ion exchanger), an average of 0.83 l;

K2 is a column of the same type, but with a loading of 0.75 L of strongly basic anion exchange resin AB-17 in Cl-form with a capacity of 1.4 g-eq / L. The free volume of the column is 0.23 liters.

Tanks E1, E2, E3 have a usable volume of 3 liters, and tanks E5 and E8 - 8 liters each. The capacity of E20 for waste solutions has a volume of more than 20 liters.

A laboratory rotary evaporator with a capacity of up to 1 l / h is used as a vacuum crystallizer (WRC).

As a desalination plant (OPR), a laboratory electrodialysis unit with a capacity of up to 4 l / h in demineralized water is used.

In addition, a sulfate separator is used, which is used as a laboratory nanofiltration unit (NF) with a capacity of 10 l / h for the processed solution and 9 l / h for permeate.

Conduct preparatory operations.

A. Transfer the ion exchanger in the K1 column into a pure K-form, for which 3.3 L of solution No. 1 is passed through it, feeding it to the bottom of the column through the E1 tank and then through line 15 with pump H1. At the same time, the flow switch P12 is both in the state of connecting pipe 3 to pipe 1. The outgoing solution is directed along a time line connecting the upper pipe of the K1 column to the inlet pipe of the E20 waste solution for subsequent disposal in liquid or solid form (after evaporation and crystallization ) At the end of the "charging" of the ion exchanger in column K1, the compounds are restored in accordance with the scheme of FIG. 5.

B. The ion exchanger in the K2 column is transferred mainly to the SO ₄ form, for which 1.7 L of solution No. 2 is passed through it, supplied through container E2 through line 22 with pump H2 to the bottom of the column. The effluent solution is sent via line 21 to the E20 waste solution tank. In this case, the flow switches P22 and P21 are both in the state of connection of the pipe 3 with the pipe 1.

C. Transfer the ion exchanger in the K3 column mainly into the K-form, for which 3.3 L of solution No. 3 is passed through it, feeding it to the bottom of the column through the E3 tank via line 18 with pump Н3. The effluent solution is sent to the capacity E20 for waste solutions through line 19. At this time, the flow switches P32 and P31 are in the state of connection of pipe 3 with pipe 1.

Next, carry out the following process steps in alternating duty cycles of 16 hours, consisting of two 8-hour half-cycles.

D1. The source of brackish water is supplied from the tank E10 via line 10.1 with the pump H1 through the input Bx.2 of the ion-exchange unit U3 to the input (upper pipe) of the K3 column and is passed at a speed of 10 l / h. In this case, switch P31 is in a state of connecting pipe 3 to pipe 2. During the first 5 minutes, the concentrated solution of potassium chloride fertilizer leaving column 2 remaining in the free volume after the previous operation is returned to container E3 (switch P32 at this time is in the state of connection of the pipe 3 with pipe 4). The rest of the time (7 hours 55 min) is transmitted sequentially through columns K3 and K1, i.e. the solution leaving the K3 column (46.8 mEq / l) through the output Exit.2 of node U1 through line 33 enters through input Bx.2 of node U1 to column K1 and then through the output Exit.2 of node U1 via line 40 to the nanofiltration unit NF. The switches P31, P32, P11, P12 are in a state of connection of pipe 3 with pipe 2.

After the nanofiltration unit, a permeate stream (9 l / h) is obtained, the composition of which is shown in table 2, and a concentrate (1 l / h), with the composition shown in table 3.

This composition is a solution of chlorine-free potassium fertilizer - potassium sulfate, which can be diluted and used for fertigation.

Chloride admixture - not more than 4%.

From the total permeate flow (9 l / h), a part, namely (2 l / h), is sent to the intermediate tank E6 via line 7, and the other part (7 l / h) is sent via line 9 to the ODP desalination plant. After the installation of ODA, desalinated water at a rate of 6.67 l / h with a residual content of potassium salts of 134 mg / l (1.8 mEq / l) is distributed as follows: part of the water (up to 2.67 l / h) along lines 11 and 11.1 is sent to a container E5, in which it is used for mixing with a solution of chlorine-free fertilizer obtained after column K2 along line 6 and preparing a diluted nutrient solution for drip irrigation. Last line 12 is sent to an external drive for the finished product. Another part of the water (4 l / h) is sent through lines 11 and 11.2 to the storage tank E8 for demineralized water.

From the intermediate vessel E6, the above-mentioned flow (2 l / h) of potassium chloride solution (26.0 mEq / l, table 2) is supplied via line 7.1 with pump Н8 through input В.2 of the ion-exchange unit U2 to column K2 with anion exchange resin sulfate form. When passing through this column for the first 7 minutes, the concentrated sodium sulfate solution leaving it, remaining in the free volume after the previous operation, is returned to the E2 tank. At this time, the flow switch P21 is in the state of connection of the pipe 3 with the pipe 2, and the switch P22 is in the state of the connection of the pipe 3 with the pipe 4.

All the time remaining until the end of the working half-cycle, namely, 7 h. 43 min., Leaving the column K2 after ion exchange, a solution of potassium sulfate (2 l / h, 26 mEq / l, or 1.85 g / l) through the output 2 of node U2 is sent along line 6 to the E5 tank for mixing with demineralized water (2.7 l / h) from the outlet of the OPR desalination plant and to obtain a solution for drip irrigation. (At this time, switch P22 is in a state of connecting pipe 3 to pipe 2). The composition of the resulting solution is shown in table 4.

Within 7 hours 50 minutes ODA desalination plant is kept on, during this time 52.2 liters of demineralized water and 2.6 liters of concentrate - solution with a potassium chloride content of 0.95 g-equiv / l are obtained. All this amount of concentrate is accumulated in the tank E1. In addition, separately prepared 0.2 l of freshly prepared solution No. 1 of pure potassium chloride (70.78 g / l or 0.95 g-equiv / l) and added to the tank E1, accumulating in the tank E1 2.8 liters of concentrate .

Chloride impurities do not exceed 4.3% with respect to the main component - potassium sulfate, sodium impurity - not more than 0.3%, the amount of calcium and iron - not more than 0.02%.

After the end of all operations to obtain a diluted fertilizer solution for drip irrigation and the accumulation of potassium chloride concentrate in the tank E1 (as described in paragraph D1 above), the steps described below in paragraph 1 are carried out. D2-D4 actions of the second half-cycle to “charge” the columns K2, K1 and K3 with the corresponding concentrated solutions, i.e. begin the operation of the regeneration of ion exchangers in the columns.

D2. 1.7 L of solution # 2 from E2 tank was passed through column K2 for 8 hours. feeding it to the bottom of the column along line 22 with pump 112. Within 1 h. 5 min. through the top of the column leaves the solution remaining in the free volume after the previous operation. It is sent through output 3 of node U2 to intermediate tank E6 via line 21.1 (at this time the flow switch P22 is in the state of connecting pipe 3 to pipe 1, and switch P21 is in the state of connecting pipe 3 to pipe 4). For the remaining 6 hours 55 minutes the concentrated solution emerging from the K2 column through the Outlet 1 exit of the U2 unit sends line E20 for waste solutions through line 21 for subsequent disposal in liquid or solid form (after evaporation and crystallization). The switch P21 at this time is in the state of connection of the pipe 3 with pipe 1.

D3, D4. The actions listed below are also performed during the 8-hour second half-cycle in parallel with the actions under item D2.

D3. On line 15 with the pump H1 through the column K1 for 8 hours pass 2.8 l of concentrated solution from the tank E1, feeding it to the bottom of the column. Within 2 hours, the solution remaining in the free volume after the previous operation comes out through the top of the column, it is sent through the output Vyh.3 of the U1 ion-exchange unit through line 16.1 to the E10 tank for the initial brackish water (the flow switch P12 is in the connection state of the pipe 3 with pipe 1, and switch P11 - in the state of connection of pipe 3 with pipe 4). During the remaining 6 hours, the concentrated solution leaving column K1 is supplied through output 1 of node U1 via line 16 and then through input Bx.1 of node U3 to tank E3 and from it along line 18 with pump H3 to the entrance of column K3. At this time, the switches P12 and P11 are both in the state of connecting pipe 3 to pipe 1.

D4. Immediately after the start of the operation and for 2 hours, through line 17 through input Вх.3 of unit U3 to tank E3 and then through line 18 with pump Н3, solution No. 1 of potassium fertilizer mixed with return solution displaced from this solution is passed through column K3 the same column at the previous stage (switch P32 at this time is in the state of connection of pipe 3 with pipe 1).

For the remaining 6 hours, in accordance with paragraph D3, a concentrated solution exiting column K1 is passed through column K3 from tank E3 through line 18 with pump H3 to the tank E3 through input Bx.1 of node U3 from output Exit 1 of node U1 on line 16 (the switches P11 and P32 are in a state of connection of pipe 3 with pipe 1). Within 2 hours, the solution remaining in its free volume after the previous operation comes out through the top of the K3 column. It is sent to the capacitance E10 through the output Vykh.3 of the U3 node and then along line 19.1 (switch P31 is in this state of connection of pipe 3 with pipe 4).

For the remaining 6 hours, the concentrated solution emerging from the K3 column through the Outlet 1 exit of the U3 unit is sent through line 19 to the E20 waste solution tank for subsequent disposal in liquid or solid form (after evaporation and crystallization). At this time, switch P31 is in a state of connecting pipe 3 to pipe 1.

After completing the steps in p.p. D1-D4 the work cycle is completed, then all the described operations are cyclically repeated.

In accordance with the steps described above, the following product line is obtained:

1. A solution of chlorine-free fertilizer - potassium sulfate in accordance with table 3 (with an average flow rate for the entire cycle - 0.5 l / h), sent to the output of the installation through line 41.

2. A solution of chlorine-free fertilizer - potassium sulfate - for drip irrigation in accordance with table 4, - 3.5 l / h, sent to the output of the installation through line 12.

3. Desalinated water, on average per cycle - 2 l / h.

Example 2

Use the real brackish underground water delivered to the laboratory with a total salinity of 3.03 g / l (0.3%) and the composition shown in Table 5. It is stored in a separate container of 100 l.

In separate containers (canisters) stocks (10 l each) of the following solutions are prepared:

- 6.8% (70.78 g / l, or 0.95 g-eq / l) of solution No. 1 of potassium chloride of the “pure” qualification in accordance with GOST 4234-77 with a negligible impurity content;

in the preparation of this solution, demineralized water obtained from tap water using a laboratory desalination plant is used;

- 6.4% (67.45 g / l, or 0.95 g-equiv / l) of solution No. 2 of sodium sulfate (technical qualification sodium sulfate grade “B” in accordance with GOST 6318-77) with calcium sulfate content no more than 1% (in solution - 0.02% in accordance with solubility) and iron - 0.03% (in solution - 0.003%);

- 6.8% (70.78 g / l, or 0.95 g-equiv / l) of solution No. 3 from a fertilizer corresponding to the qualification "Granular potassium chloride" GOST 4586-95 with a content of the main component of at least 92% and impurities salts of multiply charged ions up to 3% (up to 0.3% in the prepared solution).

In the preparation of solutions No. 2 and No. 3, tap water is used.

The prepared solutions are cleaned of solids by filtration through cartridges or a column of silica sand.

The laboratory setup is assembled according to the circuit shown in FIG. 8, so that solutions No. 1, 2, 3 can be supplied, respectively, along lines 14, 20, 17 in containers E11, E21, E31, and brackish groundwater through line 10 to container E10.

K31, K32 and K11 K12 - ion-exchange columns equipped with lower and upper drainage devices, with a loading of 2 l of strongly acidic cation exchanger KU-2 in Na - form with a capacity of 2.3 g-equiv / l. The free volume of the columns (in the porous space between the grains, as well as above the layer and under the layer of ion exchange resin) an average of 0.83 liters.

K21 and K22 are columns of the same type, but with a loading of 0.75 L of strongly basic anion exchange resin AB-17 in Cl-form with a capacity of 1.4 g-eq / L. The free volume of the columns is 0.23 liters.

Tanks E10, E20, E31, E32, E11, E12, E21, E22 have a usable volume of 1 liter, and tanks E5 and E8 - 8 liters each. The capacity of E20 for waste solutions has a volume of more than 20 liters.

A laboratory rotary evaporator with a capacity of up to 1 l / h is used as a vacuum crystallizer (WRC).

As a desalination apparatus (OPR), a laboratory two-stage reverse osmosis unit with a capacity of up to 6 l / h in demineralized water is used.

In addition, a sulfate separator is used, which is used as a laboratory nanofiltration unit (NF) with a capacity of 10 l / h for the processed solution and 9 l / h for permeate.

Conduct preparatory operations.

A. The ion exchanger is “charged” in column K12 — it is converted into a clean K-form, passing 3.3 liters of solution No. 1 through this column from bottom to top, supplied through tank E11 via line 15 with pump H1. In this case, the flow switch P12 is in the state of connecting pipe 5 to pipe 1, and the switch P13 is in the state of connecting pipe 3 to pipe 1. The solution leaving column K12 is sent to the waste water tank E20 along the time line connecting the upper pipe of column K12 with this capacity, and then along line 26 with the H7 pump to the SRS rotary evaporator for evaporation and crystallization. At the end of the “charging”, the connections are restored in accordance with the circuit of FIG. 8.

B. The ion exchanger is “charged” in column K22 — it is converted mainly to the SO ₄ form, for which 1.7 l of solution No. 2 is passed through this column from the bottom up, supplied through tank E21 via line 22 with an H2 pump. The solution leaving the K22 column through the outlet Exit 1 of the U2 ion-exchange unit through line 21 is sent to the E20 tank for waste solutions and then through line 26 with the H7 pump to the SRS rotary evaporator for evaporation and crystallization. For this, both flow switches P22, P21 must be in the state of connection of the nozzles 5 with the nozzles 1, and the switch P23 - in the state of the connection of the nozzle 3 with the nozzle 1.

C. The ion exchanger is “charged” in the K32 column — it is converted mainly to the K-form, for which 3.3 l of solution No. 3 is passed through this column, supplied through the E31 tank via line 18 with the H3 pump. The effluent solution is sent to the E20 tank for effluent solutions through line 19 through the output Exit 1 of the U3 ion-exchange unit and then through line 26 with the H7 pump to the SRS rotary evaporator for evaporation and crystallization. For this, both flow switches P32, P31 must be in the state of connection of the nozzles 5 with the nozzles 1, and the switch P33 - in the state of the connection of the nozzle 3 with the nozzle 1.

Next, carry out the following actions of the proposed method in alternating duty cycles of 16 hours, consisting of two half cycles.

The control of the flow switches, pumps and desalination apparatus in this and subsequent examples is carried out according to the time program using the amounts of solutions selected at the stage of setting up the process to ensure the ratios of the duration of operations and the quantities of ionic components in solutions, which were described in the description of the proposed method.

During the first half-cycle lasting 8 hours, sequentially parallel actions are performed, which are described in paragraphs below. D1-D5, and in the second half-cycle of the same duration - the actions described below in p. F1-F5.

D1. Operations with columns K32, K22, K12, associated with the supply of natural brackish water and obtaining a fertigation solution of chlorine-free fertilizer.

Natural brackish water is continuously supplied from the E10 tank via line 10.1 and then through the input Вх.2 of the U3 ion-exchange unit to the K32 column with a speed of 10 l / h, while the flow rates at different parts of the circuit are selected so that when performing the described switches, the characteristics described below are realized modes.

During the first 5 minutes the concentrated potassium chloride solution leaving the K32 column remaining in the free volume after the previous “charging” of cateonite is sent via line 3.1 to the E32 tank (at this time, the P32 flow switch is in the state of connecting pipe 5 to pipe 4).

The rest of the half-cycle time (7 hours 55 minutes, when switch P32 is in the state of connecting pipe 5 to pipe 2), the solution leaving the column (46.8 mEq / l) is supplied through the output 2 of the U3 ion-exchange unit through line 33 to input Вх.2 of node U1 and then to column K12 of this node (in this case, switch P11 is in the state of connecting pipe 5 to pipe 2).

In the same way, the first 5 minutes after the start of the solution supply from the output of node U3 to column K12, the concentrated solution of potassium chloride with an admixture of potassium sulfate and bicarbonate leaving the free volume after the previous operation of “charging” the cation exchange resin leaving it is sent via line 4.1 to the vessel E12 (in this case, the switch P12 is in the state of connection of the pipe 5 with pipe 4).

In the subsequent 7 hours and 50 minutes remaining until the end of the working half-cycle. the solution of potassium chloride leaving the K12 column mixed with potassium sulfate and potassium bicarbonate (46.8 mEq / L, or 3.49 g / L) enters through Exit 2 of node U1 and then through line 40 to the nanofiltration unit NF (in at this time, the flow switch P12 is in the state of connection of the pipe 5 with pipe 2). At the exit from the NF unit, permeate and concentrate (sulfate solution) are obtained. Their compositions are shown in tables 6 and 7.

Chloride admixture - not more than 0.8: 19.7 = 0.04 (4%).

Concentrate, 1 l / h. which is a sulfate-potassium solution, is a high-quality liquid fertilizer with a chloride content of not more than 4%.

Permeate, 9 l / h of potassium chloride solution, branches out into two streams, the ratio of which is regulated by valves B1 and B2 in lines 7 and 9. The first stream (3 l / h) goes through line 7 to an intermediate tank E6 and then through line 7.1 with the pump H8 through the input Bx.2 of the node U2 to the column K22 (switch P21 is in the state of connection of the pipe 5 with pipe 2). The second stream (6 l / h) along line 9 is directed to the input of the OPR desalination apparatus - a laboratory two-stage reverse osmosis unit.

After the OPR desalination unit, demineralized water having a residual potassium salt content of 72 mg / l (0.9 mEq / l) is sent at line 5.83 l / h along line 11 with a H6 pump and then through lines 11.1. and 11.2, respectively, in capacity E5 and E8. The ratio of flows along these lines is regulated by valves B3, B4. The stream entering the E8 tank (up to 1.83 l / h) is used for various needs, including those listed below, supplying water through line 11.3. The flow entering the E5 tank (up to 4 l / h) is mixed with the received solution of chlorine-free fertilizer entering the same tank via line 6 from the Outlet 2 of node U2 (switch P22 is in the state of connecting pipe 5 to pipe 2, see also below). After mixing receive a diluted nutrient solution for drip irrigation, coming in line 12.

The concentrate from the desalination apparatus - a solution of potassium chloride (0.17 l / h, 0.95 g-equiv / l) is continuously fed through line 13 with pump H5 through input Bx.1 of node U1 to tank E11 for further use in a parallel operation cation exchanger regeneration in column K11.

When passing the above-mentioned stream (3 l / h) of a solution of potassium chloride mixed with potassium sulfate and bicarbonate (26.03 mEq / l) through a K22 column with anion exchange resin in sulfate form, the concentrated sodium sulfate solution leaving the column during the first 5 minutes remaining in the free volume after the previous operation of "charging" the anion exchange resin, is sent along line 6.1 to the auxiliary capacitance E22 (switch P22 at this time is in the state of connecting pipe 5 to pipe 4).

All the time remaining until the end of the working half-cycle, namely, 7 hours and 45 minutes, leaving the K22 column after ion exchange a solution of potassium sulfate (3 l / h, 26.03 mEq / l, or 1.97 g / l) is sent through the output of Exit 2 of node U2 to line 6 (switch P22 at this time is in a state of connection of pipe 5 with pipe 2).

This solution can be further used as a mother liquor for fertigation during the preparation with the mixer of a complex fertigation nutrient solution, or it can be mixed with desalinated water (4 l / h) to obtain a diluted solution (7 l / h) of a chlorine-free high-grade sulfate potassium fertilizer for direct consumption, in particular, as a 0.1% solution for drip irrigation. The composition of such a solution is shown in table 8.

Chloride impurities do not exceed 3.9% with respect to the main component - potassium sulfate, sodium impurity - not more than 0.05%.

The next steps in p.p. D2-D4 are carried out with columns K31, K21, K11 and are associated with the regeneration ("charging") of ion exchangers with concentrated solutions.

D2. In parallel with the actions described in paragraph D1, during each working half-cycle (8 hours), the following actions are performed.

On line 20, they begin to continuously feed solution No. 2 (6.4%, or 67.45 g / l, or 0.95 g-equiv / l sodium sulfate) through the input Вх.1 of node U2 into the E21 tank and until the end of the cycle continue feeding at a speed of 0.1 l / h, but at the same time for 1 h. 49 min. the solution does not come out of this tank (the connection of the pipe 3 of the П23 switch with the pipe 1 is absent), but it simply fills.

In 10 minutes. after the start of the half cycle from the E22 tank via line 22 with the H2 pump through the K21 column with anion exchange resin from the bottom up, they start passing 0.23 L of sodium sulfate return solution (loaded there: according to point D1 at the beginning of the working half cycle) and continue at a rate of 0.1 l / h for 1 hour 39 minutes (At this time, switch P22 is in the state of connecting pipe 3 to pipe 1, and switch P23 is in the state of connecting pipe 3 to pipe 2).

The same volume of solution (0.23 L) leaving column K21 is sent to intermediate tank E6 via line 21.1 through output 3 of node U2 (switch P21 is in the state of connecting pipe 3 to pipe 4). Immediately after the expiration of 1 hour 49 minutes after the start of the half-cycle, the state of the flow switch П23 is changed so that its nozzle 3 is connected to the nozzle 1, and the solution from the tank E21 starts to be supplied at a speed of 0.1 l / h along line 22 with pump H2 through the column K21 in the direction from the bottom up and down through the output Exit 1 of node 2 along line 21 to the E20 tank for waste solutions (at this time switches P22 and P21 are each in the state of connection of pipe 3 with pipe 1). The feed from the tank E21 continues until the end of the working half-cycle. In total, 0.56 L of concentrated solution from the K21 anion exchange column is fed into the E20 tank through line 21 within one working half-cycle (actually - within 6 hours 11 minutes).

In the tank E20, the effluent solutions entering there are mixed, which are then fed via line 26 to the H7 pump to the SRS rotary evaporator.

D3 (actions are performed in parallel with the actions in paragraph D2).

Immediately after the start and during the working half-cycle, a freshly prepared solution of pure potassium chloride is supplied to line E11 of the ion-exchange unit U1 via line 14 at a rate of 0.006 l / h (just 0.05 l per 8-hour half-cycle). In parallel with this, on line 13 with a pump Н5, a potassium chloride concentrate (0.95 g-equiv / l) is continuously fed from the desalination apparatus of the ODA at a rate of 0.17 l / h through the input Вх.1 of the ion-exchange unit U1. The feed is continued until the end of the working half-cycle, but for 1 hour 40 minutes. the solution does not come out of this tank (there is no connection between the branch pipe 3 of the P13 switch and the branch pipe 1), but it simply fills. After 5 minutes after the start of the half cycle from tank E12, line 15 with pump H1 starts passing through the K11 column with cation exchange resin 0.83 l of bottom-up concentrated potassium chloride solution loaded therein in accordance with paragraph D1 at the beginning of the working half-cycle (switch P13 to this time is in the state of connection of the pipe 3 with pipe 2, and the switch P12 is in the state of connection of the pipe 3 with pipe 1). Passage is carried out at a rate of 0.275 l / h for 2 hours 50 minutes The solution (0.8 L) leaving the free volume of the K11 column is sent to the E10 tank for water to be processed through the output of Exit 3 of node 1 along line 16.1 (switch P11 is at this time in the state of connection of pipe 3 with pipe 4). Immediately after 2 hours 55 minutes after the start of the half-cycle, the state of the P13 switch is changed so that its pipe 3 is connected to the pipe 1, and the solution from the container E11 is started at a rate of 0.285 l / h through the column K11 and fed from the output of the Output 1 of node U1 via line 16 through the input Input 1 into the capacitance E31 of the U3 node (switches P12 and P11 at this time are each in the state of connection of pipe 3 with pipe 1). In total, 1.4 l of such a solution passes through a container E31 during a working half-cycle.

D4. Immediately after the start and during the working half-cycle, a freshly prepared potassium fertilizer solution (70.78 g / l or 0.95 g-equiv / l) at a rate of 0.4 l / h (only 3.2 liters of such a solution in an 8-hour half-cycle).

The supply to the container E31 of a concentrated solution of potassium chloride as per item D3 (from column K11) at a rate of 0.275 l / h, and the specified freshly prepared fertilizer solution at a rate of 0.4 l / h, continue until the end of the working half-cycle, but for 1 h. 18 min. the solution does not come out of the E31 tank (there is no connection between the nozzle 3 of the P33 switch and the nozzle 1), but it simply fills.

At the same time, immediately after the start of the half cycle from the E32 tank, through line 18 with the H3 pump, through the K31 column with cation exchange resin in the upward direction, 0.83 L of concentrated potassium chloride return solution loaded therein begins to flow in accordance with D1 at the beginning of the working half cycle ( switch P33 is in a state of connecting its pipe 2 to pipe 2, and switch P32 is in a state of connecting pipe 3 to pipe 1).

The passage is carried out at a speed of 0.64 l / h for 1 h. 18 minutes The solution emerging from the free volume of the column K31 of the U3 assembly (0.83 L) is sent to the tank E10 for water to be processed through line 19.1 through the output 3 of the U3 assembly (switch P31 is in the state of connecting pipe 3 to pipe 4).

Immediately after 1 hour 18 minutes after the start of the half-cycle, the state of switch P33 is changed so that its pipe 3 is connected to pipe 1, and the solution from the container E31 is started at a rate of 0.67 l / h through column K31 and fed from output 1 of node U3 through line 19 into the E20 tank for waste solutions (switches P32 and P31 at this time are each in the state of connecting pipe 3 to pipe 1). In total, 3.97 L of concentrated solution from cation exchange columns is fed into the E20 tank within one working half-cycle (actually - within 6 hours 42 minutes).

D5. After the accumulation of 1 liter of mixed effluent in the E20 tank, a periodic process of evaporation in the rotary evaporator SRS with a capacity of up to 1 l / h begins. Evaporation is carried out until a suspension with T: G is formed: no more than 1: 2, the suspension is unloaded, cooled and filtered on a Buchner filter using filter paper with a blue ribbon under a water-jet pump, the solution above the precipitate is returned to the E20 tank, 1 liter of mixed waste solution from the tank E20 is again poured into a rotary evaporator, the process of vacuum evaporation, suspension selection, cooling, filtration and filtrate return to the E20 tank is repeated, etc. (equipment for such repetitive actions in the diagram of Fig. 4 is not shown). The resulting wet sediments are combined and collected. In general, 4.6 l is processed in WRC in an 8-hour half-cycle (0.576 l / h).

Further actions (items F1-F5) are performed during the second half of the cycle lasting 8 hours.

F1. Perform actions similar to those described in paragraph D1, with the difference that instead of columns K12, K22, K32 they are performed with the participation of columns K11, K21, K31.

F2-F4. Perform actions similar to those described in p. D2-D4, with the difference that instead of columns K11, K21, K31 they are performed with the participation of columns K12, K22, K32.

F5. Continue to carry out all operations in accordance with paragraph D5.

Next, all operations are cyclically repeated in accordance with D1-D5 and F1-F5.

In accordance with the steps described above, the requirements for reagents in a stationary process with repeating work cycles are as follows:

1. The initial solution of brackish water in accordance with table 1-10 l / h

2. Potassium chloride qualification "Ch" in accordance with GOST 4234-77 - 0.5 g / h. To prepare solution No. 1 (0.007 l / h 70.78 g / l, or 0.95 g-eq / l), 0.007 l / h of desalinated water is taken from container E8 through line 11.3.

3. "Granular potassium chloride" GOST 4586-95 with a content of the main component of at least 92% and impurities of salts of multiply charged ions up to 3% - 27 g / h. To prepare solution No. 3 (0.5 l / h 70.78 g / l, or 0.95 g-eq / l), line 0.5 l / h of condensate is taken from SRS along line 23.

4. "Sodium sulfate technical grade" B "in accordance with GOST 6318-77 with a calcium sulfate content of not more than 1% and iron 0.03% - 6.82 g / h. For the preparation of solution No. 2 (0.1 l / h, 67.45 g / l, or 0.95 g-eq / l) along line 23, they take 0.1 l / h of condensate from the SRS.

In accordance with the operations described above, the following line of products and waste is obtained (in a stationary process with repeating work cycles):

1. A solution of chlorine-free fertilizer - potassium sulfate for drip irrigation in accordance with table 4, - 7 l / h (exit from the installation on line 12).

2. Desalinated water with a content of 1.8 mEq / l (134 mg / l) of potassium chloride, supplied to the consumer through line 11.3 - 1.48 l / h.

3. Condensate SRS with a salt content of up to 500 mg / l - 0.55 l / h.

4. Sludge (sodium chloride) with a moisture content of up to 20% - 40 g / hour. The composition of the precipitate (% wt.) Calculated on the anhydrous product: NaCl - 92.3; Na ₂ SO ₄ - 0.2; CaCl ₂ - 3.0; CaCO ₃ - 2.4; MgCO ₃ 0.2; KCl - 1.0; K ₂ SO ₄ - 0.1; CaSO ₄ - not more than 0.1; Fe + other - 0.1.

5. A solution of chlorine-free fertilizer - potassium sulfate for drip irrigation in accordance with table 3 - 1 l / h. (exit from the installation on line 41).

Using a nanofiltration unit allows you to:

- through the use of internal reserves - sulfate contained in the source water, to increase the yield (in terms of dry potassium sulfate) more than 3.5 times (19.7 g in addition to 7.4 g without the installation of NF); at the same time, the consumption of "bad" potassium chloride (for example, granular fertilizer) increases from 7.7 g / h to 27 g / h; the balance between equivalent amounts of agrochemically valuable ionic components in the consumed simple fertilizers and the same components in the composition of the obtained complex fertilizers is maintained;

- eliminate the problems associated with sedimentation (gypsum formation) in the columns;

- eliminate the problems associated with the formation of deposits and sediments (the same gypsum) in a vacuum crystallization apparatus.

Example 3

The process is carried out in accordance with example 2, except that as a concentrated regenerating solution No. 2 (for "charging" the anion exchange resin in column K22), solution No. 4, namely, a solution of ammonium nitrate, 8% (83 g / l or 1.01 g-equiv / l), prepared from a fertilizer corresponding to the qualification GOST 2-2013 Ammonium nitrate, grade “B”, 2nd grade, against the background of tap water (nitrogen content - 34%, the content of the main product NH ₄ NO ₃ - not less than 97.1%, water content - not more than 0.6%, the rest - the content of nitrates and sulfates of magnesium and calcium, etc. other impurities - of the order of not more than 2.3%).

Besides:

- during the preparatory operation B, the ion exchanger in the K22 column is converted mainly to the NO ₃ form, for which 1.6 l of solution No. 4 is passed through the column;

- when performing the steps of item D1, namely, when passing through a K22 column with anion exchange resin in a nitrate form a stream of 3 l / h of a solution of potassium chloride (26.03 mEq / l), a solution of potassium nitrate leaving the column after ion exchange ( 3 l / h, 26 mEq / l or 2.57 g / l) are sent via line 6 to the E5 tank.

This solution can be further used as a mother liquor of potassium nitrate in the process of preparing a complex fertigation nutrient solution, or it can be mixed with desalinated water (4 l / h) to obtain a diluted solution (7 l / h) of a chlorine-free high-grade potassium nitrate fertilizer for direct consumption, in particular as a 0.15% solution for drip irrigation. The composition of such a solution is shown in table 9.

Chloride impurities do not exceed 2.4% with respect to the main component - potassium sulfate, sodium impurity - not more than 0.03%.

In addition, unlike example 1, when performing steps according to p. D2 along line 20 through the input Вх.1 of the ion-exchange unit U2, solution No. 4 is supplied to the container E21; 0.22 L of ammonium nitrate return solution is passed from the E22 tank via line 22 with the H2 pump through the K21 column with anion exchange resin in a bottom-up direction (switch P22 is in the state of connecting pipe 3 to pipe 1 at this time, and switch P23 is in the connecting state pipe 3 with pipe 2).

In accordance with the operations described above, the following line of products and waste is obtained (in a stationary process with repeating work cycles):

1. A solution of chlorine-free fertilizer - potassium nitrate - for drip irrigation in accordance with table 5, - 7 l / h.

2. Desalinated water with a content of 1.8 mEq / l (134 mg / l) of potassium chloride, supplied to the consumer through line 11.3 - 1.48 l / h.

3. Condensate SRS with a salt content of up to 500 mg / l - 0.55 l / h.

4. Precipitate (ammonium chloride) with a moisture content of up to 20% - 36.9 g / hour. The composition of the precipitate (% wt.) Calculated on the anhydrous product: NH ₄ Cl - 92,0; NaCl - 1.2; (NH ₄ ) ₂ SO ₄ 0.2; CaCl ₂ - 3.0; CaCO ₃ - 2.3; MgCO ₃ 0.2; KCl - 1.0; K ₂ SO ₄ - 0.1; CaSO ₄ - not more than 0.1; Fe + other - 0.1.

5. A solution of chlorine-free fertilizer - potassium sulfate - for drip irrigation in accordance with table 3, - 1 l / h.

The use of a nanofiltration unit allows, due to the use of sulfate contained in the source water, to produce significantly more chlorine-free fertilizers, and at the same time two types: potassium nitrate and potassium sulfate.

Example 4

The process is carried out in accordance with example 2, except that instead of a concentrated regenerating solution No. 3 (for "charging" the cation exchange resin in column K31), solution No. 5 is used, namely, a 0.95 N solution of magnesium chloride (with a total salinity of 49, 5 g / l) from natural bischofite with a ratio of the components contained in it: (%):

magnesium chloride - 94; calcium sulfate - 0.2; sodium chloride - 0.4; potassium chloride and magnesium - 3.0; magnesium sulfate - 1.5; iron is 0.03.

The same bischofite solution is used instead of regenerating solution No. 1 for the treatment of cation exchange resin in column K11.

Get a solution of magnesium sulfate for drip irrigation or foliar application of the composition shown in table 10.

In addition, analogously to example 1, receive an additional amount: 1 l of a solution of magnesium sulfate in the form of a concentrate after nanofiltration, which can be diluted and used for drip irrigation.

Chloride admixture - not more than 5%.

Example 5

The process is carried out as described in example 4, except that instead of solution No. 2 (0.95 n sodium sulfate), solution No. 6 is prepared, namely, a solution of ammonium dihydrogen phosphate (monoammonium phosphate special, soluble grade A, practically free of significant impurities ) Solution No. 5 is prepared with a concentration of: 109.3 g / l (0.95 g-eq / l) and is served during operations in accordance with paragraphs. D2 or F2 with a flow rate of 0.1 l / h. Get the product, the composition of which is shown in table 12.

Chloride impurities do not exceed 2.5% with respect to the main component - potassium nitrate, sodium admixture - not more than 0.1%), the amount of calcium and iron - not more than 0.01%.

In addition, receive 1 l / h of a solution of potassium sulfate (an additional amount of chlorine-free potassium fertilizer) in the form of a concentrate after nanofiltration with the composition shown in table 13.

Chloride admixture - not more than 4%.

Example 6

The process is carried out as in example 2, however, a solution of the initial brackish water (after purification from iron) is used, shown in table 14.

In addition, unlike example 2, the duration of the operation of passing a solution of brackish water through the columns, as well as the duration of the regeneration operation ("charging columns") is chosen to be 4 hours 30 minutes.

Get products - solutions of chlorine-free potash fertilizers, the composition of which is shown in tables 15 and 16. Admixtures of chloride do not exceed 4.5% with respect to the main component - potassium nitrate, an admixture of sodium - not more than 0.2%, the sum of calcium and iron - not more than 0.02%.

Chloride admixture - not more than 9%.

The proposed invention can be used in agriculture to obtain fertilizer solutions for intensive crop production. They can be successfully applied in irrigated irrigation regions. The most effective inventions related to the proposed method and installation for its implementation can be applied in intensive crop production on closed and open soils to obtain solutions for drip irrigation, leaf and root dressing.

Information sources

1. USSR copyright certificate No. 82032, signed for publication on 05/05/1961.

2. RF patent No. 2138149, publ. 09/27/1999.

3. RF patent No. 2281255, publ. 08/10/2006.

4. F. Helferich. Ionites. M., ed. foreign literature, 1962, p. 153-155.

5. Tokmachev M.G., Tikhonov N.A., Khamizov R.Kh. Investigation of cyclic self-sustaining process for softening water solutions on the basis of mathematical modeling. React Funct. Polym., 2008, V. 68, P. 1245-1252.

6. A.B. Zhadan, E.H. Bushuev. The practical implementation of countercurrent ion exchange technology. "Bulletin of the ISEU", vol. 5, 2012, p. 1-6.

7. V.A. Tver. Membrane separation processes. Polymeric membranes. M, Moscow Art Theater M.V. Lomonosov, 2008, 59 p.

Claims (27)

1. A method of processing natural brackish water to obtain a solution of complex mineral fertilizer, comprising the implementation of a cyclically repeating process, in each cycle of which the operation of sequentially passing natural brackish water supplied from the tank for water to be processed, and intermediate solutions of its processing from top to bottom, is performed the first and second ion exchange columns containing the ion exchanger, respectively, in the form of an agrochemically valuable cationic component and agrochemically of the anionic component of the resulting complex mineral fertilizer, as well as the operation of regeneration of ion exchangers in ion-exchange columns, in which a regenerating solution is supplied to each ion-exchange column from the bottom up from the container used for this solution in conjunction with this column, in addition, when sequential transmission of natural brackish water and intermediate solutions of its processing carry out the separation of the flow of an intermediate solution of processing natural brackish water in two parts, the first part is sent to the second ion-exchange column to obtain at its outlet a stream of a solution of complex mineral fertilizer directed to the process outlet, the second part is directed to desalination to obtain a salt concentrate and a stream of demineralized water to dilute the solution of complex mineral fertilizer and other purposes, the ionite regeneration operation in each cycle is carried out using the specified salt concentrate obtained during desalination as part of the regenerating solutions, as well as a concentrate solutions of two salts, one of which contains an agrochemically valuable cationic component, and the other an agrochemically valuable anionic component of the obtained complex mineral fertilizer, characterized in that it additionally uses a third ion-exchange column containing an ion exchanger in the form of the specified cationic component, as well as a container for the regenerating solution ion exchanger of this column and natural brackish water is passed through this column before passing through the first ion-exchange column from top to bottom, in ok, from the outlet of the first ion-exchange column, they are sent to nanofiltration to separate substances with singly charged anions and substances with multiply charged anions to obtain their solutions, respectively, in the form of permeate and concentrate, and the above two parts of the flow of the intermediate solution of processing natural brackish water are obtained by separation into two parts of the permeate stream after nanofiltration, the concentrate after nanofiltration is sent to the output of the process as an additional stream of the obtained complex mineral fertilizers, for the regeneration of the ion exchanger in the first ion exchange column, the salt concentrate obtained by desalination is used; as the regenerating solution for the regeneration of the ion exchanger in the third ion exchange column, the regenerate obtained from the regeneration of the ion exchanger in the first ion exchange column is used together with the said concentrated salt solution containing an agrochemically valuable cationic component, and pass the regenerating solution through the third ion exchange column in the direction from the bottom up, to regenerate the ion exchanger into the second ion exchange said concentrated solution of salt containing said agrochemically valuable anionic component is used in the column, while the regenerating solution is passed through the first and third ion-exchange columns for a time until a breakthrough occurs at the outlet of the third ion-exchange column of the indicated agrochemically valuable cationic component and through the second ion-exchange column for the time before the onset of a slip at its exit of the specified agrochemically valuable anionic component, and the operation sequential skip The digging of natural brackish water and intermediate solutions of its processing through ion-exchange columns is performed for a period of time until a breakthrough occurs at the outlet of the first or second ion-exchange column of any of the agrochemically harmful ionic components contained in natural brackish water or salts used in the composition of regeneration solutions. 2. The method according to p. 1, characterized in that the intermediate container is additionally used and in each cycle the first part of the permeate stream obtained after nanofiltration, sent to the second ion exchange column, is preliminarily fed into this container, in which the displaced at the beginning of execution is added to the specified part ion exchange regeneration operation, the solution remaining in the free volume of the second ion exchange column from the previously performed operation of sequential transmission of natural brackish water and intermediate solutions of it processing, and the mixed solution obtained in the intermediate tank is sent to this column, and the solution remaining in the free volume of the first and third ion-exchange columns displaced at the beginning of the ion exchange regeneration operation is sent to the tank for natural brackish water to be processed, in addition, in each the cycle at the beginning of the operation of sequential passing through the ion-exchange columns of natural brackish water and intermediate solutions of its processing displaced regenerating solution remaining in free ion exchange column volume each of these operations performed before regeneration of the ion exchanger in the column is fed to a container for regenerant solution to be used in conjunction with this column. 3. The method according to p. 2, characterized in that in each cycle, the operation of regeneration of ion exchangers and the operation of sequentially passing natural brackish water and intermediate solutions of its processing are carried out in parallel, for which additional ion exchange columns are used, forming respectively the first, second and third pairs with the indicated the first, second and third ion-exchange columns and containing the same ion exchanger, each of these containers for a regenerating solution used in conjunction with the first, second and third ion-exchange columns, is common for both ion-exchange columns forming a pair, during one half of the cycle when using one of the ion-exchange columns of each pair in the operation of sequentially passing natural brackish water and intermediate solutions of its processing, another ion-exchange column of the same pair is used in the operation of ion exchange regeneration, and in the other half of the cycle, the types of operations that use ion-exchange columns of the indicated pairs are changed. 4. The method according to p. 1, characterized in that the intermediate container is additionally used and in each cycle the first part of the permeate stream obtained after nanofiltration, sent to the second ion exchange column, is preliminarily fed into this container, in which the displaced at the beginning of execution is added to the indicated part ion exchange regeneration operation, the solution remaining in the free volume of the second ion exchange column from the previously performed operation of sequential transmission of natural brackish water and intermediate solutions of it processing, and the mixed solution obtained in the intermediate tank is sent to this column, and the solution remaining in the free volume of the first and third ion-exchange columns displaced at the beginning of the ion exchange regeneration operation is sent to the tank for the natural brackish water to be processed, in addition, together with each of these first, second and third ion-exchange columns additionally use auxiliary capacity and in each cycle at the beginning of the sequential transmission of natural solo water and intermediate solutions of its processing displaced regeneration solution remaining in the free volume of the ion exchange column in which such an operation is performed after the operation of regeneration of the ion exchanger in this column is carried out before, is sent to the specified auxiliary tank, and when performing the next operation of regeneration of ion exchanger before feeding The ion-exchange column of the regenerating solution from the tank for such a solution uses the solution located in this auxiliary tank. 5. The method according to p. 4, characterized in that in each cycle, the operation of regeneration of ion exchangers and the operation of sequentially passing natural brackish water and intermediate solutions of its processing are carried out in parallel, for which additional ion exchange columns are used, forming respectively the first, second and third pairs with the indicated the first, second and third ion-exchange columns and containing the same ion exchanger, each of these containers for the regenerating solution and auxiliary containers used together but with the first, second, and third ion-exchange columns, it is common for both ion-exchange columns to form a pair, during one half of the cycle, when using one of the ion-exchange columns of each pair in the operation of sequentially passing natural brackish water and intermediate solutions of its processing, another ion-exchange column of the same the pairs are used in the operation of regeneration of the ion exchanger, and in the other half of the cycle, the types of operations that use ion-exchange columns of the indicated pairs are changed. 6. The method according to any one of paragraphs. 1-5, characterized in that as cation exchange resin and anion exchange resin in ion-exchange columns, respectively, strongly acidic sulfocationite and strongly basic anion exchange resin with quaternary ammonium bases are used. 7. The method according to p. 6, characterized in that as these salts, concentrated solutions of which are used in the operation of regeneration of ion exchangers, low-grade simple fertilizers are used. 8. The method according to any one of paragraphs. 1-5, 7, characterized in that when using the salt concentrate obtained by desalination as a regenerating solution for an ion exchanger in the first ion-exchange column or in one of the ion-exchange columns of the first pair, a concentrated salt solution containing an agrochemically valuable cationic is added to each concentrate in each cycle component of the obtained complex mineral fertilizer, which is cleaner in the content of impurities in comparison with the salt used in the concentrated solution for the regeneration of ion exchanger in tre an ion-exchange column or in one of the ion-exchange columns of the third pair, with the amount of such salt in the added concentrated solution equal to the equivalent amount of the indicated cationic component carried out during desalination with the volume of demineralized water obtained in the cycle, using the added salt solution as well as the salt solution used in the regeneration of ion exchange resin in addition to the specified regenerate, with the same concentration as the salt concentrate obtained by desalination. 9. The method according to p. 8, characterized in that the resulting solution of a complex mineral fertilizer is diluted with desalted water obtained after desalination to achieve the concentration necessary for fertigation. 10. The method according to any one of paragraphs. 1-5, 7, 9, characterized in that the waste solutions in the form of regenerates obtained by performing ionite regeneration operations in the ion exchange columns of the second and third pairs are combined and then sent for processing by vacuum crystallization. 11. The method according to p. 10, characterized in that during desalination use the desalination method from the group including electrodialysis, reverse osmosis method, thermodistillation method, as well as cold distillation methods - the vaporization method and the method of capacitive distillation. 12. Installation for processing natural brackish water to obtain a solution of complex mineral fertilizer, containing a container for the natural brackish water to be processed, having outlet and inlet pipes, first and second ion-exchange columns having each upper and lower drainage devices, respectively, with upper and lower pipes, the first and second containers for regenerating solutions having each inlet and outlet nozzles, desalination apparatus having an inlet nozzle, an outlet nozzle for desalination water and an outlet pipe for salt concentrate, the first ion exchange column containing cation exchange resin and the second anion exchange resin in the form of respectively agrochemically valuable cationic and anionic components of the resulting complex mineral fertilizer, characterized in that it contains first, second and third ion-exchange units, each of which contains an ion exchange column having upper and lower drainage devices, respectively, with upper and lower nozzles, each ion exchange unit also contains a container for regenerating solution, having an outlet pipe and an inlet pipe, which is the first input of the ion-exchange unit and is designed to supply a regenerating solution into it, the first and second flow switches, each with four pipes and configured to connect the third pipe to the first, second or fourth, the third nozzles of the first and second flow switches are connected respectively to the upper and lower nozzles of the ion exchange column, the second nozzle of the first flow switch is the second ion input the exchange node, which is designed to supply the solution processed in the ion exchange column, the first nozzle of the first flow switch is the first outlet of the ion exchange node, which is designed to remove the regenerate from the ion exchange column, the fourth nozzle of the first flow switch forms the third exit of the ion exchange column, which is designed to remove the processed solution displaced from the free volume of the ion exchange column, the outlet pipe of the tank for the regenerating solution of the compound n with the first branch pipe of the second flow switch, the second branch pipe of the second flow switch is the second output of the ion-exchange unit, which is designed to remove the solution processed in the ion-exchange column, while the first and second ion-exchange columns are respectively the first and second ion-exchange columns, and the capacities of these ion-exchange units for regenerating solutions - the indicated first and second containers for regenerating solutions, respectively, ion-exchange columns The third ion-exchange unit contains cation exchange resin in the form of an agrochemically valuable cationic component of the resulting complex mineral fertilizer, and the capacity for the regenerating solution in this ion-exchange unit has an additional inlet pipe, which is the third input of this ion-exchange unit, which is designed to supply a salt solution containing an agrochemically valuable cationic component complex mineral fertilizers, in addition, the capacity for the regenerating solution in each ion-exchange unit is equipped with one inlet pipe connected to the fourth pipe of the second flow switch, this installation also contains an intermediate tank having two inlet pipes and an outlet pipe, while the second input of the third ion-exchange unit is connected to the output pipe of the tank for the natural brackish water to be processed, the second output of this ion-exchange the node is connected to the second input of the first ion-exchange unit, the first output of which is connected to the first input of the third ion-exchange unit, the first input of the first ion-exchange of this node is connected to the outlet pipe of the desalination apparatus for salt concentrate, the first input of the second ion-exchange unit is designed to supply a salt solution containing an agrochemically valuable anionic component of the obtained complex mineral fertilizer, and its second output is the output of the specified installation for the resulting solution of complex mineral fertilizer also equipped with a nanofiltration unit for separating substances with singly charged anions and substances with multiply charged anions having an input an outlet pipe connected to the second outlet of the first ion-exchange unit, an outlet pipe for permeate and an outlet pipe for concentrate, which is the output of the specified installation for the resulting additional solution of complex mineral fertilizer, the outlet pipe for permeate of the specified nanofiltration unit is connected to the inlet pipe of the desalination apparatus and one of inlet pipes of intermediate capacity with the ability to control the ratio of flows arising from this separation of the permeate flow, with the third output of the second ion-exchange unit is connected to it by the input pipe of the intermediate tank, and the second input of the second ion-exchange unit is connected to the output pipe of the intermediate capacity, the third outputs of the first and third ion-exchange units are connected to the input pipes of the tank for natural brackish water to be processed, and the first outputs of the second and third ion-exchange nodes are the outputs of the specified installation for waste solutions. 13. Installation according to p. 12, characterized in that each ion-exchange unit is additionally introduced another ion-exchange column, forming a pair with its specified ion-exchange column, with the same ion exchanger and having upper and lower drainage devices, respectively, with upper and lower the lower nozzles, the first and second flow switches each are additionally equipped with a fifth nozzle and are made with the additional possibility of connecting this nozzle to any of the nozzles of the group including the first, second and fourth pa cuttings, wherein none of the nozzles of the group can not be simultaneously coupled to the third and fifth, said fifth branch pipes of the first and second streams of switches respectively connected to upper and lower nozzles of said additionally introduced ion exchange column. 14. Installation according to claim 12 or 13, characterized in that said ion-exchange columns contain, respectively, strongly acid sulfonic cation and a strongly basic anion exchange resin with quaternary ammonium bases as cation exchange resin and anion exchange resin. 15. Installation according to claim 14, characterized in that the container for the regenerating solution in the first ion-exchange unit is provided with an additional inlet pipe, which forms the third inlet of this ion-exchange unit, designed to supply an additional component of the regenerating solution for the cation exchange resin used in this ion-exchange unit. 16. Installation according to any one of paragraphs. 12, 13, 15, characterized in that it further comprises a vacuum crystallization apparatus and a container for waste solutions having inlet and outlet nozzles, a vacuum crystallization apparatus is connected at its inlet to an outlet nozzle of the indicated capacity, and the inlet nozzles of this container are connected to the first the outputs of the second and third ion-exchange nodes. 17. Installation according to claim 16, characterized in that each of the following connections: a second inlet of a third ion-exchange unit with an outlet nozzle of a tank for water to be processed, an outlet nozzle of a desalination apparatus for salt concentrate with a first inlet of a first ion-exchange node, an outlet nozzle of an intermediate tank with the second input of the second ion-exchange unit and the outlet pipe of the tank for the regenerating solution with the first pipe of the second flow switch in each ion-exchange unit, is carried out by a line neighing pump. 18. Installation according to any one of paragraphs. 12, 13, 15, 17, characterized in that the desalination apparatus is made with the possibility of implementing the desalination method from the group including electrodialysis, reverse osmosis method, thermodistillation method, and also cold distillation methods - the vaporization method and the method of capacitive distillation. 19. The installation according to p. 18, characterized in that it further comprises a container for preparing a dilute solution of the obtained complex mineral fertilizer having an outlet and inlet nozzles, and a storage tank for demineralized water having an inlet and outlet nozzles, one of the inlet nozzles containers for the preparation of a dilute solution of the obtained complex mineral fertilizers are connected to the second outlet of the second ion-exchange unit, the other inlet pipe of this tank and the inlet pipe accumulatively demineralised water tank connected with an outlet desalination apparatus demineralized water, with the ratio flow regulation supplied to these capacitances. 20. Installation for processing natural brackish water to obtain a solution of complex mineral fertilizer, containing a container for the natural brackish water to be processed, having outlet and inlet pipes, first and second ion-exchange columns having each upper and lower drainage devices, respectively, with upper and lower pipes, the first and second containers for regenerating solutions having each inlet and outlet nozzles, desalination apparatus having an inlet nozzle, an outlet nozzle for desalination water and an outlet pipe for salt concentrate, the first ion exchange column containing cation exchange resin and the second anion exchange resin in the form of respectively agrochemically valuable cationic and anionic components of the resulting complex mineral fertilizer, characterized in that it contains first, second and third ion-exchange units, each of which contains an ion exchange column having upper and lower drainage devices, respectively, with upper and lower nozzles, each ion exchange unit also contains a container for regenerating solution, having an outlet pipe and an inlet pipe, which is the first input of the ion exchange unit and is designed to supply a regenerating solution, and an auxiliary tank having an inlet and outlet pipe, as well as the first, second and third flow switches, with the first and second the flow switches each have four nozzles and are configured to connect the third nozzle to the first, second or fourth, the third nozzles of the first and second flow switches are connected respectively to hnim and lower nozzles of the ion exchange column, the third flow switch has three nozzles and is configured to connect the third nozzle to the first or second, while its first and second nozzles are connected respectively to the outlet nozzle of the tank for the regenerating solution and the outlet nozzle of the auxiliary tank, the third nozzle of this the flow switch is connected to the first pipe of the second flow switch, and the fourth pipe of the latter is connected to the inlet pipe of the auxiliary tank, the second pipe the first flow switch is the second input of the ion-exchange unit, which is designed to supply the solution processed in the ion-exchange column, the first nozzle of the first flow switch is the first output of the ion-exchange unit, which is designed to remove the regenerate from the ion-exchange column, the fourth nozzle of the first flow switch forms the third output of the ion-exchange unit, which is designed to remove the processed solution, displaced from the free volume of the ion exchange column, sec the second branch pipe of the second flow switch is the second output of the ion-exchange unit, which is designed to remove the solution processed in the ion-exchange column, while the first and second ion-exchange columns are respectively the first and second ion-exchange columns, and the capacities of these ion-exchange units for regenerating solutions are respectively indicated the first and second containers for regenerating solutions, the ion-exchange column of the third ion-exchange unit contains cation exchange resin in the form of a a rochemical valuable cationic component of the obtained complex mineral fertilizer, and the capacity for the regenerating solution in this ion-exchange unit has an additional inlet pipe, which is the third input of this ion-exchange unit, which is designed to supply a salt solution containing an agrochemically valuable cationic component of the obtained complex mineral fertilizer, the specified installation contains also an intermediate tank having two inlet nozzles and an outlet nozzle, while the second input of the third ion exchange The connected node is connected to the outlet pipe of the tank for natural brackish water to be processed, the second output of this ion-exchange unit is connected to the second input of the first ion-exchange unit, the first output of which is connected to the first input of the third ion-exchange unit, the first input of the first ion-exchange unit is connected to the output pipe of the desalination apparatus for salt concentrate, the first input of the second ion-exchange unit is designed to supply a salt solution containing an agrochemically valuable anionic component obtained with false mineral fertilizer, and its second output is the output of the specified installation for the resulting solution of complex mineral fertilizers, this installation is also equipped with a nanofiltration unit for separating substances with singly charged anions and substances with multiply charged anions having an inlet connected to the second output of the first ion-exchange unit, the output a pipe for permeate and an outlet pipe for concentrate, which is an additional output of the specified installation for the solution obtained complex of ineral fertilizer, the outlet pipe for the permeate of the indicated nanofiltration unit is connected to the inlet pipe of the desalination apparatus and one of the inlet pipes of the intermediate tank with the ability to control the ratio of flows arising from this separation of the permeate stream, the third output of the second ion-exchange unit is connected to the other inlet pipe of the intermediate tank, and the second input of the second ion-exchange unit is connected to the output pipe of the intermediate capacity, the third outputs of the first and third ion-exchange units s are connected to the inlets for the container to be processed natural brackish waters, while the first outputs of the second and third ion exchange sites are the outputs of said units for waste solutions. 21. The installation according to p. 20, characterized in that each ion-exchange unit is additionally introduced another ion-exchange column, forming a pair with the specified ion-exchange column belonging to it, with the same ion exchanger and having upper and lower drainage devices, respectively, with upper and lower nozzles , the first and second flow switches each are additionally equipped with a fifth nozzle and are made with the additional possibility of connecting this nozzle to any of the nozzles of the group including the first, second and fourth pat ubki, wherein none of the nozzles of the group can not be simultaneously coupled to the third and fifth, said fifth branch pipes of the first and second streams of switches respectively connected to upper and lower nozzles of said additionally introduced ion exchange column. 22. Installation according to claim 20 or 21, characterized in that said ion-exchange columns contain strongly acidic sulfocationite and strongly basic anion exchange resin with quaternary ammonium bases as cation exchange resin and anion exchange resin. 23. Installation according to claim 22, characterized in that the container for the regenerating solution in the first ion-exchange unit is equipped with an additional inlet pipe, which forms the third inlet of this ion-exchange unit, designed to supply an additional component of the regenerating solution for the cation exchange resin used in this ion-exchange unit. 24. Installation according to any one of paragraphs. 20, 21, 23, characterized in that it further comprises a vacuum crystallization apparatus and a capacity for waste solutions having inlet and outlet nozzles, a vacuum crystallization apparatus is connected at its inlet to an outlet nozzle of the indicated capacity, and the inlet nozzles of this capacity are connected to the first the outputs of the second and third ion-exchange nodes. 25. Installation according to p. 24, characterized in that each of the following connections: a second inlet of a third ion-exchange unit with an outlet pipe of a container for water to be processed, an outlet pipe of a desalination apparatus for salt concentrate with a first inlet of a first ion-exchange unit, an outlet pipe of an intermediate tank with the second input of the second ion-exchange unit and the third nozzle of the third flow switch with the first nozzle of the second flow switch in each ion-exchange unit, implemented by a line containing pump. 26. Installation according to any one of paragraphs. 20, 21, 23, 25, characterized in that the desalination apparatus is made with the possibility of implementing the desalination method from the group including electrodialysis, reverse osmosis method, thermodistillation method, as well as cold distillation methods - the vaporization method and the method of capacitive distillation. 27. The installation according to p. 26, characterized in that it further comprises a container for preparing a diluted solution of the obtained complex mineral fertilizer having an outlet and inlet nozzles, and a storage tank for demineralized water having an inlet and outlet nozzles, one of the inlet nozzles containers for the preparation of a dilute solution of the obtained complex mineral fertilizers are connected to the second outlet of the second ion-exchange unit, the other inlet pipe of this tank and the inlet pipe accumulatively demineralised water tank connected with an outlet desalination apparatus demineralized water, with the ratio flow regulation supplied to these capacitances.

Images