Adsorption / segmented circulation thickening desorption method and device

Abstract

The invention provides an adsorption / segmented circulation thickening desorption method and device. According to the adsorption / segmented circulation thickening desorption method, firstly, produced water is pretreated, bicarbonate radicals are introduced to adjust the pH alkalinity of the produced water so that the produced water can be more suitable for being used by a titanium adsorbent, and then the segmented circulation thickening desorption step is carried out. And carrying out one-time surface desorption and at least one-time internal pore leaching on each group of adsorption devices reaching the adsorption end point, preferably accompanying pretreatment, and recycling carbon dioxide in the adsorption process, so that low-carbon efficient lithium extraction of the produced water of the chloride type oil and gas field is realized.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of produced water resource utilization, and particularly relates to an adsorption / segmented cyclic concentration desorption method and device. BACKGROUND

[0002] With the importance of lithium resources and the increase in market demand, oil and gas field produced water lithium extraction has attracted more and more attention at home and abroad due to its advantages of good implementation of industrial foundation, pollution reduction and carbon reduction, and good resource utilization effect. Oil and gas field produced water lithium extraction is still in its infancy, and current pilot tests have proved that the effective technical route for oil and gas field produced water lithium extraction is "pretreatment + enrichment and concentration (adsorption-membrane separation) + precipitation". The adsorption method for lithium extraction generally uses lithium selective adsorbents such as resin-based aluminum oxide adsorbents, lithium aluminum oxide intercalation adsorbents, aluminum oxide adsorption ion exchange resins, or aluminum oxide-based adsorbents.

[0003] Aluminum-based adsorbents have the characteristics of good cycle stability, low energy consumption, fast adsorption rate, and long service life, and can be used for lithium extraction from magnesium sulfate type brine and chloride type brine. It is a lithium adsorbent that is widely used in industrial applications, but aluminum-based adsorbents generally use clean water for desorption, and the concentration of lithium is generally about 10 times. However, the concentration of lithium ions in oil and gas field produced water is relatively low, with an average concentration of about 35-40 mg / L. Therefore, the concentration of lithium obtained by using aluminum-based adsorbents is relatively low, which puts a heavy burden on the subsequent membrane concentration scale and energy consumption. Titanium-based adsorbents have the characteristics of high adsorption capacity and can use acid solution for cyclic desorption to achieve high lithium desorption liquid. However, the specific adsorption of lithium by titanium-based adsorbents depends on Li-H exchange, which is generally suitable for alkaline brine systems, but not for chloride type oil and gas field produced water.

[0004] Therefore, in order to maximize the advantages of titanium-based adsorbents and efficiently extract lithium resources from chloride type oil and gas field produced water, it is urgent to develop a method and corresponding device for high-efficiency adsorption and desorption of lithium ions in chloride type oil and gas field produced water, which can overcome the defects of titanium-based adsorbents not being suitable for chloride type oil and gas fields, in order to develop oil and gas field produced water lithium extraction technology and obtain high lithium desorption liquid. SUMMARY

[0005] In view of the above problems existing in the prior art, the purpose of the present application is to provide an adsorption / segmented cyclic concentration desorption method and device, which overcomes the defects of titanium-based adsorbents not being suitable for chloride type oil and gas fields and realizes efficient extraction of lithium from low chloride type produced water.

[0006] To achieve the above-mentioned purpose, one of the present applications provides an adsorption / segmented cyclic concentration desorption method, comprising the following steps:

[0007] S1. reacting liquid alkali or lime water with carbon dioxide in produced water to produce bicarbonate to adjust pH, to obtain pretreated produced water with a pH not less than 7.5;

[0008] S2. performing target ion adsorption and stepwise cyclic concentration desorption on the pretreated produced water to obtain a target ion-rich desorption solution; wherein the target ion concentration is not less than 1 g / L.

[0009] According to the present application, in step S2, the pretreated produced water is subjected to target ion adsorption by using an adsorption device filled with a target ion selective adsorbent.

[0010] According to the present application, in step S2, the stepwise cyclic concentration desorption includes surface desorption and internal pore channel leaching performed in stages in sequence.

[0011] First, the adsorption device that has reached the adsorption endpoint is subjected to 1 time of surface desorption to desorb the target ions adsorbed on the surface of the target ion selective adsorbent.

[0012] Then, the adsorption device is subjected to at least 1 time of internal pore channel leaching to migrate the target ions remaining in the internal pore channels of the target ion selective adsorbent, to obtain the target ion-rich desorption solution.

[0013] According to the present application, in step S2, the pretreated produced water is introduced into n groups of adsorption devices to perform target ion adsorption, to produce carbon dioxide and adsorption tail liquid, until the n groups of adsorption devices all reach the adsorption endpoint; n is an integer ≥ 2; each group of adsorption devices includes at least 1 adsorption column.

[0014] Preferably, in the adsorption tail liquid, the concentration of the target ions is not higher than 10 mg / L.

[0015] According to the present application, in step S2, the stepwise cyclic concentration desorption is performed by the following methods:

[0016] When n = 2 or n is an integer ≥ 3, 1 time of surface desorption is performed on the first group of adsorption devices using acid liquid to produce a first-stage desorption solution; n-1 times of internal pore channel leaching are performed on the first group of adsorption devices using washing liquid, and the leaching liquid produced each time is collected separately.

[0017] When n is an integer ≥ 3, 1 time of surface desorption is performed on the mth group of adsorption devices using the acid liquid and the leaching liquid produced by the first time of internal pore channel leaching of the (m-1)th group of adsorption devices to produce an mth-stage desorption solution; n-m times of internal pore channel leaching are performed on the mth group of adsorption devices using the leaching liquid produced by the second to n-(m-1) times of internal pore channel leaching of the (m-1)th group of adsorption devices, and the leaching liquid produced each time is collected separately; m is an integer from 2 to (n-1).

[0018] When n=2 or n is an integer greater than or equal to 3, the acid solution and the eluate produced by the first internal pore channel leaching of the (n-1)th group of adsorption devices are combined, the (n)th group of adsorption devices is subjected to the first surface layer desorption to produce the nth grade desorption solution; the (n)th group of adsorption devices is subjected to at least one internal pore channel leaching with the eluate to produce an eluate which is combined with the adsorption tail solution;

[0019] The first to nth grade desorption solutions are collected to obtain the target ion-rich desorption solution.

[0020] The adsorption devices which have completed the internal pore channel leaching continue to perform the target ion adsorption.

[0021] According to the present application, the n groups of adsorption devices are assembled in a fixed bed or a continuous ion exchange mode; and n is an integer greater than or equal to 2.

[0022] According to the present application, the rate of the internal pore channel leaching is 1 to 5 times the rate of the surface layer desorption.

[0023] Preferably, when the n groups of adsorption devices are assembled in a continuous ion exchange mode, the rate of the surface layer desorption is 2 to 4 times the adsorption rate; and n is an integer greater than or equal to 2.

[0024] According to the present application, the target ion is lithium ion.

[0025] Preferably, the target ion selective adsorbent is a titanium-based adsorbent or a manganese-based adsorbent.

[0026] According to the present application, in the second to nth groups of adsorption devices, when any group of adsorption devices performs the surface layer desorption, the pH of the combined acid solution and the eluate produced by the first internal pore channel leaching of the previous group of adsorption devices is 1.5 to 2.0; n is an integer greater than or equal to 2; and / or

[0027] The pH of the acid solution is 1.5 to 2.0; and / or

[0028] The eluate is water.

[0029] According to the present application, the carbon dioxide produced by the target ion adsorption in the n groups of adsorption devices is collected and used in the reaction with liquid caustic or lime water in step S1 to produce bicarbonate to adjust the pH of the produced water, thereby achieving carbon dioxide recycling; and n is an integer greater than or equal to 2.

[0030] Preferably, the carbon dioxide recycling further includes collecting the carbon dioxide escaping from the produced water during the reaction and reinjecting it into the produced water.

[0031] The second aspect of the present application provides an adsorption / sectional cyclic concentration desorption device for implementing the adsorption / sectional cyclic concentration desorption method according to the first aspect of the present application, comprising:

[0032] The pre-treatment unit provides a place for the reaction of liquid caustic or lime water with carbon dioxide in produced water, so that the liquid caustic or lime water reacts with carbon dioxide in the produced water to produce bicarbonate to adjust the pH, and the pre-treated produced water has a pH not lower than 7.5;

[0033] The adsorption / sectional cyclic concentration desorption unit is connected to the pre-treatment unit and is used for adsorbing the target ions and sectional cyclic concentration desorption of the pre-treated produced water to obtain a desorption liquid rich in target ions; wherein the concentration of the target ions is not less than 1 g / L.

[0034] The application of the adsorption / sectional cyclic concentration desorption method according to the first aspect of the present application or the adsorption / sectional cyclic concentration desorption device according to the second aspect of the present application in the utilization of associated resources in produced water;

[0035] Preferably, the produced water refers to chloride type produced water; and / or the content of bicarbonate in the produced water is not higher than 150 mg / L.

[0036] The present application has the following beneficial effects:

[0037] In view of the problem that the specific adsorption of lithium by the existing titanium-based adsorbent depends on Li-H exchange and is not suitable for chloride type oil and gas field produced water, and there is a lack of methods and devices suitable for efficient lithium extraction from chloride type oil and gas field produced water, the present application provides an adsorption / sectional cyclic concentration desorption method and device. Compared with the prior art, the present application has at least the following advantages:

[0038] 1. A pre-treatment step for the produced water is provided, and the bicarbonate produced by the reaction of liquid caustic or lime water with excess carbon dioxide gas in the produced water adjusts the pH of the produced water to not less than 7.5, providing a suitable alkaline produced water environment for the subsequent lithium adsorption process of the titanium-based adsorbent, overcoming the defect that the titanium-based adsorbent depends on Li-H exchange and is more suitable for alkaline environment but not suitable for chloride type oil and gas field produced water which is itself acidic, which is beneficial to maximize the advantages of high lithium adsorption capacity of the titanium-based adsorbent, and further beneficial to realize efficient lithium extraction from chloride type oil and gas field produced water.

[0039] 2. On the basis of setting the pretreatment step for produced water, the present application also designs the special desorption mode of segmented cycle concentration desorption. Unlike the conventional acid liquid cycle desorption, the lithium ions desorbed are not discharged in time due to the mixed cycle use of acid liquid and desorption liquid, which produces concentration inhibition effect on the subsequent cycle desorption process and reduces the lithium desorption efficiency. In the segmented cycle concentration desorption designed by the present application, for the multiple groups of adsorption devices reaching the adsorption end point, only the acid liquid or the acid liquid and the leaching liquid produced by the first internal channel leaching of the last group of adsorption devices are used to perform one surface layer desorption, so as to desorb a large amount of ions adsorbed on the surface layer of the titanium-based adsorbent into the desorption liquid for separate storage; after the surface layer desorption, the leaching liquid produced by the second to last internal channel leaching of the last group of adsorption devices is used to perform not less than one internal channel leaching, so as to make the residual lithium ions in the internal channel of the titanium-based adsorbent migrate from the channel of the titanium-based adsorbent by using the concentration gradient. In the above-mentioned segmented cycle concentration desorption process, since the acid liquid does not contain lithium ions, the lithium ions contained in the leaching liquid combined with the acid liquid are also very few compared with the desorption liquid, so that the concentration inhibition effect caused by the existence of lithium ions in the surface layer desorption process is almost avoided, and thus a large amount of lithium ions can be desorbed with high desorption efficiency; and the leaching liquid or water as the washing liquid for internal channel leaching can make the residual lithium ions in the internal channel of the titanium-based adsorbent migrate by using the concentration gradient on the basis of the surface layer desorption, so as to realize the almost complete desorption of lithium ions; the combination of the surface layer desorption and the internal channel leaching realizes the efficient extraction and high recovery rate of lithium in the produced water of the chloride type oil and gas field. In addition, the combination of the leaching liquid and the acid liquid for surface layer desorption also realizes the recycling of the leaching liquid, which is conducive to reducing the amount of acid liquid used in the surface layer desorption process and saving the lithium extraction cost.

[0040] 3. It is also preferred to set the carbon dioxide recovery step, one is to collect the carbon dioxide escaped from the produced water in the pretreatment process, and inject it into the produced water in the pretreatment step, for reacting with lime water or liquid alkali to introduce bicarbonate; two is that in the lithium ion adsorption process of the titanium-based adsorbent, hydrogen ions and bicarbonate react to generate carbon dioxide gas, the present application also collects the part of carbon dioxide generated in the lithium ion adsorption process, and injects it into the produced water in the pretreatment step, for reacting with lime water or liquid alkali to introduce bicarbonate, which realizes the carbon dioxide recovery and recycling in the whole process of lithium adsorption / desorption, and is more low-carbon and environmentally friendly. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 The step schematic diagram of the adsorption / segmented cycle concentration desorption method provided by the present application;

[0042] Figure 2 The specific flow schematic diagram of the adsorption / segmented cycle concentration desorption method provided by the embodiment of the present application;

[0043] Figure 3 A specific flowchart of a sectioned cyclic concentration desorption step in the adsorption / sectioned cyclic concentration desorption method provided by the embodiment of the present application is shown in the figure;

[0044] Figure 4 A structural schematic diagram of the adsorption / sectioned cyclic concentration desorption device provided by the embodiment of the present application is shown in the figure, wherein the adsorption device adopts a fixed bed type assembly mode, and the adsorption devices are connected in parallel;

[0045] Figure 5 A structural schematic diagram of the adsorption / sectioned cyclic concentration desorption device provided by the embodiment of the present application is shown in the figure, wherein the adsorption device adopts a fixed bed type assembly mode, and the adsorption devices are connected in series;

[0046] Figures 6 to 8 A structural schematic diagram of the adsorption zone, surface layer desorption zone and internal pore channel leaching zone when the adsorption device in the adsorption / sectioned cyclic concentration desorption device provided by the embodiment of the present application adopts a continuous ion exchange type assembly mode is shown in the figure, wherein the adsorption devices are connected in series;

[0047] Figures 9 to 11 A structural schematic diagram of the adsorption zone, surface layer desorption zone and internal pore channel leaching zone when the adsorption device in the adsorption / sectioned cyclic concentration desorption device provided by the embodiment of the present application adopts a continuous ion exchange type assembly mode is shown in the figure, wherein the adsorption devices are connected in parallel.

[0048] In the figure, 11 is a first precipitation device, 12 is a second precipitation device, 13 is a pH detection device, 14 is a pretreated produced water container, 211 is an adsorption device, 212 is an adsorption tail liquid container, 221 is an acid liquid container, 222 is a desorption liquid container, 223 is an intermediate container, 224 is a washing liquid container, 31 is a carbon dioxide storage device, and 32 is a carbon dioxide conveying device. DETAILED DESCRIPTION

[0049] The present application will be further described below in conjunction with the embodiments, but the embodiments of the present application are only exemplary descriptions, and the embodiments do not constitute a limitation on the present application in any case.

[0050] The titanium-based adsorbent has the characteristics of high adsorption capacity and high lithium desorption liquid by acid liquid circulation desorption. However, the specific adsorption of lithium by the titanium-based adsorbent depends on Li-H exchange, and is generally suitable for the alkaline brine system, but not suitable for the chloride type oil and gas field produced water. In order to maximize the advantages of the titanium-based adsorbent, it is urgent to develop an adsorption and desorption device and method which can overcome the defects of the titanium-based adsorbent not suitable for the chloride type oil and gas field, so that the titanium-based adsorbent can efficiently adsorb and desorb lithium ions in the chloride type oil and gas field produced water, and obtain high lithium desorption liquid.

[0051] As shown in Figure 1 The first aspect of the present application provides an adsorption / sectional cyclic concentration desorption method, comprising the following steps: S1. reacting liquid caustic or quicklime with carbon dioxide in produced water to generate bicarbonate to adjust pH, to obtain pretreated produced water with a pH not lower than 7.5; S2. performing target ion adsorption and sectional cyclic concentration desorption on the pretreated produced water to obtain target ion-rich desorption liquid; wherein the concentration of the target ion is not lower than 1 g / L. For chloride-type oil and gas field produced water, the target ion particularly refers to lithium ion. The adsorption / sectional cyclic concentration desorption method provided by the present application is first based on the specific adsorption principle of titanium-based adsorbent for lithium ion and the characteristics that the titanium-based adsorbent is suitable for alkaline brine system, combined with the characteristics that chloride-type oil and gas field produced water is acidic, a pretreatment step for adjusting pH is designed before adsorption / desorption, bicarbonate is generated by the reaction of liquid caustic or lime water with carbon dioxide to introduce bicarbonate into the produced water to play a buffering role, so as to maintain the pH of the produced water not lower than 7.5 in the subsequent adsorption step, to create suitable conditions for the specific adsorption of titanium-based adsorbent for lithium ion. On the other hand, the adsorption / sectional cyclic concentration desorption method provided by the present application uses a specially designed sectional cyclic concentration desorption in the desorption stage, which is different from the traditional acid liquid circulation desorption. The sectional cyclic concentration desorption can overcome the inhibitory effect of the target ion previously desorbed on the concentration of the target ion existing in the subsequent desorption process in the traditional acid liquid circulation desorption, improve the desorption efficiency, and obtain target ion-rich desorption liquid with higher concentration as much as possible.

[0052] In one specific embodiment of the present application, in step S1, as shown in Figure 2 The produced water becomes turbid and then clear during the reaction of lime water and carbon dioxide to generate bicarbonate. The supernatant after clarification is taken, and the pH of the supernatant is detected to be not lower than 7.5, i.e. the pretreated produced water is obtained. Or, liquid caustic and carbon dioxide are reacted to generate bicarbonate, and the produced water remains clear. The pH of the produced water is detected to be not lower than 7.5, i.e. the pretreated produced water is obtained.

[0053] The liquid caustic referred to in the present application is sodium hydroxide aqueous solution.

[0054] In one specific embodiment of the present application, the molar ratio of carbon dioxide to calcium hydroxide in lime water is greater than 2:1; or

[0055] The molar ratio of carbon dioxide to sodium hydroxide in liquid caustic is greater than 1:1.

[0056] In one specific embodiment of the present application, in step S2, the pretreated produced water is subjected to target ion adsorption by using an adsorption device filled with target ion selective adsorbent.

[0057] In one embodiment of the present application, in step S2, the pretreated produced water is passed into n groups of adsorption devices for the target ion adsorption, producing carbon dioxide and adsorption tail liquid, until the n groups of adsorption devices all reach the adsorption endpoint; n is an integer ≥ 2; each group of adsorption devices comprises at least one adsorption column.

[0058] In one embodiment of the present application, the connection mode between the n groups of adsorption devices is parallel or series.

[0059] In one embodiment of the present application, when each group of adsorption devices comprises 2 or more adsorption columns, the connection mode between the adsorption columns in the same group is series or parallel.

[0060] In one embodiment of the present application, the target ion selective adsorbent is a titanium-based adsorbent or a manganese-based adsorbent.

[0061] In one embodiment of the present application, under the condition that the molar ratio of bicarbonate and lithium ions in the pretreated produced water is not less than 1:1, when the pH of the adsorption tail liquid is < 4, it is judged that the n groups of adsorption devices reach the adsorption endpoint.

[0062] In one preferred embodiment of the present application, in the adsorption tail liquid, the concentration of the target ion is not higher than 10 mg / L.

[0063] In one embodiment of the present application, in step S2, as shown in Figure 2 The segmented cyclic concentration desorption comprises surface desorption and internal pore channel leaching carried out in stages in sequence;

[0064] First, the adsorption device reaching the adsorption endpoint is subjected to 1 time of surface desorption, desorbing the target ion selectively adsorbed by the target ion selective adsorbent on the surface;

[0065] Then, the adsorption device is subjected to at least 1 time of internal pore channel leaching, so that the residual target ion in the internal pore channel of the target ion selective adsorbent migrates down, obtaining the target ion-rich desorption liquid.

[0066] In one embodiment of the present application, in step S2, as shown in Figure 3 The segmented cyclic concentration desorption is carried out by the following mode:

[0067] When n = 2 or n is an integer ≥ 3, 1 time of surface desorption is carried out on the first group of adsorption devices with acid liquid, producing the first-stage desorption liquid; n-1 times of internal pore channel leaching are carried out on the first group of adsorption devices with washing liquid, and the leaching liquid produced each time is collected respectively;

[0068] When n is an integer greater than or equal to 3, the acid solution and the eluate produced by the first time of the internal pore channel leaching of the (m-1)th adsorption device are combined, and the (m)th adsorption device is subjected to 1 time of the surface layer desorption to produce the mth desorption solution; the eluate produced by the second to n-(m-1) times of the internal pore channel leaching of the (m-1)th adsorption device is respectively introduced into the (m)th adsorption device, and the (m)th adsorption device is subjected to n-m times of the internal pore channel leaching, and the eluate produced by each time of the leaching is collected respectively; m is an integer from 2 to (n-1);

[0069] When n is 2 or an integer greater than or equal to 3, the acid solution and the eluate produced by the first time of the internal pore channel leaching of the (n-1)th adsorption device are combined, and the (n)th adsorption device is subjected to 1 time of the surface layer desorption to produce the nth desorption solution; the eluate is introduced into the (n)th adsorption device for at least 1 time of the internal pore channel leaching, and the eluate produced by the leaching is combined into the adsorption tail solution;

[0070] The first to nth desorption solutions are collected to obtain the desorption solution rich in the target ions.

[0071] The adsorption device that has completed the internal pore channel leaching continues to perform the adsorption of the target ions.

[0072] In one specific embodiment of the present application, the n adsorption devices are assembled in a fixed bed type or a continuous ion exchange type; n is an integer greater than or equal to 2.

[0073] In one specific embodiment of the present application, when the n adsorption devices are assembled in a fixed bed type, the segmented cyclic concentration desorption is performed according to the following steps:

[0074] When n is 2 or an integer greater than or equal to 3, the acid solution is introduced into the first adsorption device for 1 time of the surface layer desorption to produce the first desorption solution; the eluate produced by each time of the leaching is collected respectively.

[0075] When n is an integer greater than or equal to 3, the acid solution and the eluate produced by the first time of the internal pore channel leaching of the (m-1)th adsorption device are combined, and the (m)th adsorption device is subjected to 1 time of the surface layer desorption to produce the mth desorption solution; then the eluate produced by the second to n-(m-1) times of the internal pore channel leaching of the (m-1)th adsorption device is respectively introduced into the (m)th adsorption device, and the (m)th adsorption device is subjected to n-m times of the internal pore channel leaching, and the eluate produced by each time of the leaching is collected respectively; wherein m is an integer from 2 to (n-1);

[0076] When n = 2 or n is an integer greater than or equal to 3, the eluate from the first internal channel leaching of the acid solution and the (n-1)th group of adsorption devices is combined and introduced into the nth group of adsorption devices to perform the surface desorption once to generate the nth stage desorption solution; the eluate from the internal channel leaching of the acid solution and the (n-1)th group of adsorption devices is combined and introduced into the nth group of adsorption devices to perform the internal channel leaching at least once to generate the eluate, which is combined with the adsorption tail liquid;

[0077] The first to nth stage desorption solutions are collected to obtain the target ion-rich desorption solution.

[0078] Any group of adsorption devices that has completed the internal channel leaching continues to perform the target ion adsorption.

[0079] In one specific embodiment of the present application, when the n groups of adsorption devices are arranged in a continuous ion exchange mode, an adsorption zone, a surface desorption zone and an internal channel leaching zone are provided; wherein,

[0080] The number of adsorption sites in the adsorption zone is at least equal to the number of adsorption columns in each group of adsorption devices; the number of desorption sites in the surface desorption zone is at least equal to the number of adsorption columns in each group of adsorption devices divided by the ratio of the surface desorption rate to the adsorption rate; and the number of leaching sites in the internal channel leaching zone is at least equal to the number of adsorption columns in each group of adsorption devices divided by the ratio of the internal leaching rate to the adsorption rate.

[0081] The n groups of adsorption devices move along the route of the adsorption sites, the desorption sites, the leaching sites and the adsorption sites in a cycle to sequentially perform the target ion adsorption, the surface desorption and the internal channel leaching, and then perform the target ion adsorption again, so that the target ion adsorption and the segmented cycle enrichment desorption are continuously and cyclically performed; n is an integer greater than or equal to 2. Based on the above arrangement, the segmented cycle enrichment desorption is performed in the following manner:

[0082] When n = 2 or n is an integer greater than or equal to 3, the first group of adsorption devices is moved to the desorption site, the acid solution is introduced to perform the surface desorption once to generate the first stage desorption solution; then the first group of adsorption devices is moved to the leaching site, and the eluate from the internal channel leaching of the acid solution and the (n-1)th group of adsorption devices is introduced to perform the internal channel leaching n-1 times, and the eluate from each leaching is collected separately.

[0083] When n is an integer greater than or equal to 3, the mth group of adsorption devices is moved to the desorption site, the eluate from the first internal channel leaching of the acid solution and the (m-1)th group of adsorption devices is combined and introduced to perform the surface desorption once to generate the mth stage desorption solution; then the mth group of adsorption devices is moved to the leaching site, and the eluate from the second to n-(m-1)th internal channel leaching of the (m-1)th group of adsorption devices is introduced to perform the internal channel leaching n-m times, and the eluate from each leaching is collected separately; wherein m is an integer from 2 to (n-1).

[0084] When n = 2 or n is an integer ≥ 3, the n th group of adsorption devices is moved to the desorption position, the acid solution and the n-1 th group of adsorption devices are combined with the eluate produced by the first internal channel elution to produce the n th stage desorption liquid, and the n th stage desorption is performed to produce the n th stage desorption liquid; then the n th group of adsorption devices is moved to the elution position, the washing solution is introduced to perform at least one internal channel elution, and the eluate is combined with the adsorption tail liquid;

[0085] The first to n th stage desorption liquids are collected to obtain the target ion-rich desorption liquid.

[0086] Any group of adsorption devices that has completed the internal channel elution is moved to the adsorption position to perform the target ion adsorption.

[0087] In one specific embodiment of the present application, the internal channel elution rate is 1 to 5 times the surface layer desorption rate.

[0088] In one specific embodiment of the present application, when the n groups of adsorption devices are arranged in a continuous ion exchange mode, the surface layer desorption rate is 2 to 4 times the adsorption rate; n is an integer ≥ 2.

[0089] In one specific embodiment of the present application, in the second to n th groups of adsorption devices, when any group of adsorption devices performs the surface layer desorption, the pH of the combined eluate of the acid solution and the eluate produced by the first internal channel elution of the previous group of adsorption devices is 1.5-2.0; n is an integer ≥ 2.

[0090] In one specific embodiment of the present application, the pH of the acid solution is 1.5-2.0; and / or

[0091] The washing solution is water.

[0092] In one specific embodiment of the present application, as shown in Figure 2 The carbon dioxide produced by the target ion adsorption in the n groups of adsorption devices is collected for the reaction with liquid caustic or lime water in step S1 to produce bicarbonate to adjust the pH of the produced water and realize carbon dioxide recycling; n is an integer ≥ 2.

[0093] In one specific embodiment of the present application, as shown in Figure 2 The carbon dioxide recycling further includes collecting the carbon dioxide escaping from the produced water during the reaction and reinjecting into the produced water.

[0094] The second aspect of the present application provides an adsorption / sectional cyclic concentration desorption device for implementing the adsorption / sectional cyclic concentration desorption method as described in the first aspect of the present application, comprising: a pretreatment unit, which provides a place for the reaction of liquid caustic or quicklime with carbon dioxide in produced water, so that the reaction of liquid caustic or quicklime with carbon dioxide in produced water produces bicarbonate to adjust the pH, and the pretreated produced water has a pH not lower than 7.5; and an adsorption / sectional cyclic concentration desorption unit, which is connected to the pretreatment unit and is used for adsorbing the target ions and performing sectional cyclic concentration desorption on the pretreated produced water to obtain a target ion-rich desorption solution; wherein the concentration of the target ions is not lower than 1 g / L.

[0095] In one specific embodiment of the present application, the pretreatment unit comprises a first precipitation device and a pH detection device; the first precipitation device provides a place for the reaction of liquid caustic or lime water with carbon dioxide to produce bicarbonate and the pH adjustment of the produced water; and the pH detection device is used for detecting the pH of the pretreated produced water.

[0096] In one specific embodiment of the present application, when the reaction of lime water and carbon dioxide is used to produce bicarbonate, the pretreatment unit further comprises a second precipitation device connected to the first precipitation device, the produced water in the first precipitation device that changes from turbidity to clarity is collected in the second precipitation device to stand, and the supernatant is generated; the pH of the supernatant detected by the pH detection device is not lower than 7.5, which is the pretreated produced water.

[0097] In one specific embodiment of the present application, the adsorption / sectional cyclic concentration desorption unit comprises an adsorption subunit and a sectional cyclic concentration desorption subunit; the adsorption subunit is connected to the pretreatment unit and is used for adsorbing the target ions in the pretreated produced water, generating carbon dioxide and an adsorption tail liquid; and the sectional cyclic concentration desorption subunit is connected to the adsorption subunit and is used for performing sectional cyclic concentration desorption on the adsorption subunit that reaches the adsorption endpoint, to obtain the target ion-rich desorption solution.

[0098] In one specific embodiment of the present application, the concentration of the target ions in the adsorption tail liquid is not higher than 10 mg / L.

[0099] In one specific embodiment of the present application, the adsorption subunit comprises n groups of adsorption devices, and each group of adsorption devices comprises at least one adsorption column.

[0100] In one specific embodiment of the present application, the connection mode between the n groups of adsorption devices is parallel or series connection, and when each group of adsorption devices comprises two or more adsorption columns, the connection mode between the adsorption columns in the same group is series or parallel connection.

[0101] In one specific embodiment of the present application, the n groups of adsorption devices are assembled in a fixed bed or a continuous ion exchange mode.

[0102] In one specific embodiment of the present application, the segmented concentration-increasing desorption subunit comprises an acid solution container, a desorption solution container, an intermediate container and a washing solution container; the acid solution container is used to hold the acid solution, the desorption solution container is used to hold the desorption solution produced by the surface desorption, the intermediate container is used to hold the leaching solution produced by the internal pore channel leaching, and the washing solution container is used to hold the washing solution; n is an integer greater than or equal to 2.

[0103] In one specific embodiment of the present application, as shown in Figure 4 , Figure 5 In one specific embodiment of the present application, the n groups of adsorption devices are assembled in a fixed bed mode; in the adsorption subunit, the liquid phase inlet of at least the first group of adsorption devices in the n groups of adsorption devices is connected to the liquid phase outlet of the first (or second) precipitation device to pass the pretreated produced water into the adsorption devices for adsorption of the target ions, producing carbon dioxide and adsorption tail liquid; in the segmented cyclic concentration-increasing desorption subunit, the washing solution container is connected to the liquid phase inlets of at least the first and the nth groups of adsorption devices in the n groups of adsorption devices; the acid solution container and the desorption solution container are respectively connected to the liquid phase inlets and outlets of the n groups of adsorption devices; n-i intermediate containers are connected in parallel between the liquid phase outlet of the ith group of adsorption devices and the liquid phase inlet of the (i+1)th group of adsorption devices; n is an integer greater than or equal to 2, and i is an integer from 1 to (n-1); to achieve the segmented cyclic concentration-increasing desorption: when n=2 or n is an integer greater than or equal to 3, the acid solution is passed into the first group of adsorption devices for 1 time of surface desorption, producing the first-stage desorption solution; the washing solution is passed into the first group of adsorption devices for n-1 times of internal pore channel leaching, and the leaching solution produced each time is collected separately; when n is an integer greater than or equal to 3, the acid solution and the leaching solution produced by the first time of internal pore channel leaching of the (m-1)th group of adsorption devices are combined and passed into the mth group of adsorption devices for 1 time of surface desorption, producing the mth-stage desorption solution; then the leaching solution produced by the 2nd to n-(m-1)th times of internal pore channel leaching of the (m-1)th group of adsorption devices is passed into the mth group of adsorption devices, and the mth group of adsorption devices is subjected to n-m times of internal pore channel leaching, and the leaching solution produced each time is collected separately; wherein m is an integer from 2 to (n-1); when n=2 or n is an integer greater than or equal to 3, the acid solution and the leaching solution produced by the first time of internal pore channel leaching of the (n-1)th group of adsorption devices are combined and passed into the nth group of adsorption devices for 1 time of surface desorption, producing the nth-stage desorption solution; the washing solution is passed into the nth group of adsorption devices for at least 1 time of internal pore channel leaching, and the leaching solution produced is combined into the adsorption tail liquid; the first to nth-stage desorption solutions are collected to obtain the target ion-rich desorption solution.

[0104] In one embodiment of the present application, as shown in Figures 6 to 11 the n groups of adsorption devices are arranged in a continuous ion exchange mode; the adsorption sub-units are used as adsorption zones; the number of adsorption sites in the adsorption zones is at least equal to the number of adsorption columns in each group of adsorption devices; the number of desorption sites in the surface desorption zones is at least equal to the number of adsorption columns in each group of adsorption devices divided by the ratio of the surface desorption rate to the adsorption rate; the number of leaching sites in the internal pore leaching zones is at least equal to the number of adsorption columns in each group of adsorption devices divided by the ratio of the internal leaching rate to the adsorption rate; the n groups of adsorption devices move along the routes of the adsorption sites, the desorption sites, the leaching sites, and the adsorption sites in a cycle, sequentially perform the target ion adsorption, the surface desorption, and the internal pore leaching, and then perform the target ion adsorption again, to continuously and cyclically perform the target ion adsorption and the stepwise cyclically concentrated desorption; and n is an integer greater than or equal to 2.

[0105] In one embodiment of the present application, as shown in Figure 6 , Figure 9 In the adsorption sites, the liquid inlet of at least the first group of adsorption devices is connected to the liquid outlet of the first precipitation device (or the second precipitation device) to pass the pretreated produced water into the adsorption devices to perform the target ion adsorption, to produce carbon dioxide and adsorption tail liquid.

[0106] As shown in Figure 7 , Figure 10 In the desorption sites, the liquid inlet and the liquid outlet of the first group of adsorption devices are connected to the acid liquid container and the desorption liquid container, respectively, to pass the acid liquid into the first group of adsorption devices to perform the surface desorption once, to produce the first-stage desorption liquid collected in the desorption liquid container.

[0107] When n is an integer greater than or equal to 3, in the second to (n-1)th groups of adsorption devices, the liquid inlet of the mth group of adsorption devices is connected to the acid liquid container and the intermediate container containing the leaching liquid produced by the first internal pore leaching of the (m-1)th group of adsorption devices, respectively, and the liquid outlet of the mth group of adsorption devices is connected to the desorption liquid container, to combine the acid liquid and the leaching liquid produced by the first internal pore leaching of the (m-1)th group of adsorption devices, and to pass them into the mth group of adsorption devices to perform the surface desorption once; to produce the mth-stage desorption liquid collected in the desorption liquid container; and m is an integer from 2 to (n-1).

[0108] When n is 2 or an integer greater than or equal to 3, the liquid phase inlet of the n-th set of adsorption devices is connected to the acid liquid container and the intermediate container containing the eluate produced by the first time internal channel leaching of the (n-1)-th set of adsorption devices, respectively, and the liquid phase outlet of the n-th set of adsorption devices is connected to the desorption liquid container, so as to combine the acid liquid and the eluate produced by the first time internal channel leaching of the (n-1)-th set of adsorption devices and input into the n-th set of adsorption devices for one time surface desorption; and the n-th stage desorption liquid is collected in the desorption liquid container.

[0109] As shown in Figure 8 、 Figure 11 At the elution position, the liquid phase inlet of the first set of adsorption devices is connected to the washing liquid container, and the liquid phase outlet is connected to n-1 intermediate containers; so as to input the washing liquid into the first set of adsorption devices for n-1 times of internal channel leaching, and the eluate produced is collected in n-1 intermediate containers, respectively.

[0110] When n is an integer greater than or equal to 3, in the second to (n-1)-th set of adsorption devices, the liquid phase inlet of the m-th set of adsorption devices is connected to n-m intermediate containers containing the eluate produced by n-m times of internal channel leaching of the (m-1)-th set of adsorption devices, so as to perform n-m times of internal channel leaching on the m-th set of adsorption devices; and the liquid phase outlet of the m-th set of adsorption devices is connected to n-m intermediate containers, so as to collect the eluate produced in n-m intermediate containers, respectively.

[0111] When n is 2 or an integer greater than or equal to 3, the liquid phase inlet of the n-th set of adsorption devices is connected to the washing liquid container, so as to input the washing liquid into the n-th set of adsorption devices for at least one time of internal channel leaching; and the liquid phase outlet of the n-th set of adsorption devices is connected to the adsorption tail liquid container, so as to combine the eluate produced into the adsorption tail liquid.

[0112] In one specific embodiment of the present application, the adsorption devices are filled with the target ion selective adsorbent.

[0113] In one specific embodiment of the present application, the target ion is lithium ion.

[0114] In one specific embodiment of the present application, the target ion selective adsorbent is titanium-based adsorbent or manganese-based adsorbent.

[0115] In one specific embodiment of the present application, the pH of the acid liquid is 1.5-2.0.

[0116] In one specific embodiment of the present application, the washing liquid is water.

[0117] In one specific embodiment of the present application, the device further comprises a carbon dioxide recycling unit; the carbon dioxide recycling unit is connected with the pretreatment unit and the adsorption / sectional cyclic concentration desorption unit respectively, for collecting the carbon dioxide generated by the adsorption of the target ions in the adsorption / desorption unit, and providing carbon dioxide to the pretreatment unit.

[0118] In one specific embodiment of the present application, as shown in Figure 4 、 Figure 5 、 Figure 6 、 Figure 9 The carbon dioxide recycling unit comprises a carbon dioxide storage device and a carbon dioxide delivery device; the outlet and the inlet of the carbon dioxide storage device are connected with the gas phase inlet of the first precipitation device and the gas phase outlet of the adsorption device respectively, so as to collect the carbon dioxide generated by the adsorption of the target ions in the adsorption device, and provide the required carbon dioxide for the first precipitation device.

[0119] In one specific embodiment of the present application, as shown in Figure 4 、 Figure 5 、 Figure 6 、 Figure 9 The inlet of the carbon dioxide storage device is further connected with the gas phase outlet of the first precipitation device, so as to recover the carbon dioxide escaped from the produced water in the first precipitation device.

[0120] The application of the adsorption / sectional cyclic concentration desorption method according to the first aspect of the present application or the adsorption / sectional cyclic concentration desorption device according to the second aspect of the present application in the utilization of produced water associated resources.

[0121] In one specific embodiment of the present application, the produced water refers to chloride type produced water; and / or the content of bicarbonate in the produced water is not higher than 150 mg / L.

[0122] The adsorption / sectional cyclic concentration desorption method provided by the present application is further described below in combination with specific examples.

[0123] The titanium-based adsorbent used in the following examples / contrastive examples is metatitanic acid type adsorbent.

[0124] Example 1

[0125] In this example, the lithium ions in the tail water after the extraction of bromine (hereinafter referred to as the produced water to be extracted for lithium) obtained by further electrolytic extraction of bromine from the lithium ion solution obtained by the oil suspension removal treatment and the monovalent / divalent ion separation treatment of the produced water in sequence are adsorbed / desorbed by using the adsorption / sectional cyclic concentration desorption device provided by the present application and implementing the adsorption / sectional cyclic concentration desorption method provided by the present application.

[0126] 1. Composition information of produced water / produced water to be extracted for lithium

[0127] Initial composition of produced water: lithium 65 mg / L, bromine 230 mg / L, rubidium 56 mg / L, bicarbonate 150 mg / L, oil 2500 mg / L, suspended solids 110 mg / L.

[0128] Composition of produced water to be extracted for lithium: lithium 52 mg / L, bicarbonate 50 mg / L.

[0129] 2. Adsorption / subsection cyclic concentration desorption device information

[0130] A pretreatment unit comprising a first precipitation device and a second precipitation device connected in series, and a pH detection device;

[0131] An adsorption / subsection cyclic concentration desorption unit comprising an adsorption subunit and a subsection cyclic concentration desorption subunit;

[0132] The adsorption subunit comprises 4 groups of adsorption devices, each group of adsorption devices comprising 4 adsorption columns connected in series, and each adsorption column is filled with 1200g of titanium-based adsorbent; The 4 groups of adsorption devices are connected in parallel between the 1st to 4th groups of adsorption devices; The liquid phase outlet of the second precipitation device is connected to the liquid phase inlet of the 1st to 4th groups of adsorption devices, respectively;

[0133] The subsection cyclic concentration desorption unit comprises an acid liquid container, a desorption liquid container, an intermediate container and a washing liquid container, the acid liquid container contains dilute hydrochloric acid, the desorption liquid container contains desorption liquid, the intermediate container contains elution liquid, and the washing liquid container contains water; The liquid phase inlets of the 1st and 4th groups of adsorption devices are connected to the washing liquid container, respectively; The liquid phase inlets and outlets of the 1st to 4th groups of adsorption devices are connected to the acid liquid container and the desorption liquid container, respectively; n-i intermediate containers are connected in parallel between the liquid phase outlet of the ith group of adsorption devices and the liquid phase inlet of the (i+1)th group of adsorption devices; n is 4, and i is an integer from 1 to (n-1);

[0134] The carbon dioxide circulation unit comprises a carbon dioxide storage device and a carbon dioxide conveying device; The outlet and inlet of the carbon dioxide storage device are connected to the gas phase inlet of the first precipitation device and the gas phase outlet of the 1st to 4th groups of adsorption devices, respectively, and the inlet of the carbon dioxide storage device is also connected to the gas phase outlet of the first precipitation device.

[0135] 3. Adsorption / subsection cyclic concentration desorption of lithium ions in produced water to be extracted for lithium

[0136] S1. Reacting lime water with carbon dioxide in produced water to be extracted for lithium to produce bicarbonate to adjust pH, to obtain pretreated produced water with a pH not less than 7.5;

[0137] Specifically, the lithium-extraction water to be extracted is introduced into a first precipitation device, and then saturated lime water and excess carbon dioxide gas are introduced into the lithium-extraction water to be extracted, so that the lithium-extraction water to be extracted first becomes turbid and then becomes clear, the saturated lime water and the carbon dioxide react to generate bicarbonate in the lithium-extraction water to be extracted, and the molar ratio of the bicarbonate and lithium ions in the lithium-extraction water to be extracted is controlled to be 1:1; after the lithium-extraction water to be extracted becomes clear, the lithium-extraction water to be extracted is introduced into a second precipitation device, and the pH of the supernatant is detected by a pH detection device, and the pH of the supernatant is not less than 7.5, and the supernatant is the pretreated produced water; in this process, the carbon dioxide gas escaping from the lithium-extraction water to be extracted in the first precipitation device is recovered to the carbon dioxide storage device for storage and reinjection into the first precipitation device for preparation of bicarbonate.

[0138] S2. The pretreated produced water is subjected to target ion adsorption and stepwise cyclic concentration desorption to obtain a target ion-rich desorption liquid; wherein the target ion concentration is not less than 1 g / L.

[0139] Specifically, the pretreated produced water obtained in step S1 is introduced into the liquid phase inlets of the first to fourth groups of adsorption devices at a flow rate of 35 mL / min, the pretreated produced water flows through the first to fourth groups of adsorption devices for lithium ion adsorption, and after the adsorption subunit is stably operated for 1 h, the adsorption tail liquid is collected, and the content of lithium ions in the adsorption tail liquid is reduced to 5 mg / L; according to the average content of lithium in the adsorption tail liquid after the adsorption subunit is stably operated for 24 h, which is 6 mg / L, it is calculated that the adsorption recovery rate of lithium ions is 89%;

[0140] Under the condition that the molar ratio of bicarbonate and lithium ions in the lithium-extraction water to be extracted is controlled to be 1:1 in step S1, when the pH of the adsorption tail liquid is measured to be less than 4, it is determined that the first to fourth groups of adsorption devices reach the adsorption endpoint, and the first to fourth groups of adsorption devices are subjected to stepwise cyclic concentration desorption: the dilute hydrochloric acid contained in the acid liquid container is introduced into the liquid phase inlet of the first group of adsorption devices at a flow rate of 70 mL / min (or referred to as a desorption flow rate) to perform 1 time of surface desorption, and the first-stage desorption liquid is collected in the desorption liquid container; the water in the washing liquid container is introduced into the liquid phase inlet of the first group of adsorption devices at a flow rate of 140 mL / min to perform 3 times of internal channel leaching, and the leaching liquid produced by each leaching is collected in 3 intermediate containers connected in parallel between the liquid phase outlet of the first group of adsorption devices and the liquid phase inlet of the second group of adsorption devices;

[0141] The elution liquid produced by the first internal channel leaching of the first group of adsorption devices in the intermediate container is combined with the dilute hydrochloric acid in the acid liquid container (the pH of the combined elution liquid is 1.5-2.0) and then is introduced into the liquid phase inlet of the second group of adsorption devices at a flow rate of 70 mL / min to perform one surface layer desorption, and the desorption liquid produced is collected in the desorption liquid container; the elution liquid produced by the second and third internal channel leachings of the first group of adsorption devices in the intermediate container is introduced into the liquid phase inlet of the second group of adsorption devices in turn to perform two internal channel leachings, and the elution liquid produced by each leaching is collected in two intermediate containers connected in parallel between the liquid phase outlet of the second group of adsorption devices and the liquid phase inlet of the third group of adsorption devices;

[0142] The elution liquid produced by the first internal channel leaching of the second group of adsorption devices in the intermediate container is combined with the dilute hydrochloric acid in the acid liquid container (the pH of the combined elution liquid is 1.5-2.0) and then is introduced into the liquid phase inlet of the third group of adsorption devices at a flow rate of 70 mL / min to perform one surface layer desorption, and the desorption liquid produced is collected in the desorption liquid container; the elution liquid produced by the second internal channel leaching of the second group of adsorption devices in the intermediate container is introduced into the liquid phase inlet of the third group of adsorption devices to perform one internal channel leaching, and the elution liquid produced is collected in one intermediate container connected in parallel between the liquid phase outlet of the third group of adsorption devices and the liquid phase inlet of the fourth group of adsorption devices;

[0143] The elution liquid produced by the first internal channel leaching of the third group of adsorption devices in the intermediate container is combined with the dilute hydrochloric acid in the acid liquid container (the pH of the combined elution liquid is 1.5-2.0) and then is introduced into the liquid phase inlet of the fourth group of adsorption devices at a flow rate of 70 mL / min to perform one surface layer desorption, and the elution liquid produced is collected in the desorption liquid container; the water in the elution liquid container is introduced into the liquid phase inlet of the fourth group of adsorption devices at a flow rate of 140 mL / min to perform one internal channel leaching, and the elution liquid produced is combined with the adsorption tail liquid;

[0144] The carbon dioxide gas produced in the process of the segmented cyclic concentration desorption is recovered from the gas phase outlets of the first to fourth groups of adsorption devices to the carbon dioxide storage device by the carbon dioxide conveying device and is injected into the first precipitation device for preparation of bicarbonate;

[0145] It is determined that the average concentration of lithium ions in the desorption liquid (i.e., lithium ion-rich desorption liquid) produced by the surface layer desorption of the first to fourth groups of adsorption devices is 1.1 g / L, the concentration of lithium ions in the elution liquid produced by the internal channel leachings of the first to third groups of adsorption devices is 100 mg / L, and the average desorption recovery rate of lithium ions contained in the lithium ion-rich desorption liquid is 95%.

[0146] Example 2

[0147] The embodiment utilizes the adsorption / segmented cyclic concentration desorption device provided by the application to implement the adsorption / segmented cyclic concentration desorption method provided by the application, and adsorbs and desorbs lithium ions in tail water after bromine extraction of lithium ion solution obtained by sequentially performing oil suspension removal treatment and monovalent / divalent ion separation treatment on produced water and further performing electrolytic bromine extraction.

[0148] 1. Component information of produced water / lithium extraction produced water

[0149] Initial components of the produced water: lithium 65 mg / L, bromine 230 mg / L, rubidium 56 mg / L, bicarbonate 150 mg / L, oil 2500 mg / L, and suspended solids 110 mg / L.

[0150] Components of the lithium extraction produced water: lithium 52 mg / L, bicarbonate 50 mg / L.

[0151] 2. Adsorption / segmented cyclic concentration desorption device information

[0152] The pretreatment unit includes a first precipitation device and a second precipitation device connected in series, and a pH detection device;

[0153] The adsorption / segmented cyclic concentration desorption unit includes an adsorption subunit and a segmented cyclic concentration desorption subunit;

[0154] The adsorption subunit includes two groups of adsorption devices, each group of adsorption devices includes eight adsorption columns connected in parallel, and each adsorption column is filled with 1200 g of titanium-based adsorbent; the two groups of adsorption devices are connected in series between the first and second groups of adsorption devices in a fixed bed type assembly manner; the liquid phase outlet of the second precipitation device is connected to the liquid phase inlet of the first group of adsorption devices;

[0155] The segmented cyclic concentration desorption unit includes an acid liquid container, a desorption liquid container, an intermediate container, and a washing liquid container; the acid liquid container contains dilute hydrochloric acid, the desorption liquid container contains desorption liquid, the intermediate container contains elution liquid, and the washing liquid container contains water; the washing liquid container is connected to the liquid phase inlets of the first and second groups of adsorption devices; the acid liquid container and the desorption liquid container are connected to the liquid phase inlets and outlets of the first and second groups of adsorption devices, respectively; and one intermediate container is connected in parallel between the liquid phase outlet of the first group of adsorption devices and the liquid phase inlet of the second group of adsorption devices.

[0156] The carbon dioxide circulation unit includes a carbon dioxide storage device and a carbon dioxide conveying device; the outlet and inlet of the carbon dioxide storage device are connected to the gas phase inlet of the first precipitation device and the gas phase outlets of the first and second groups of adsorption devices, respectively, and the inlet of the carbon dioxide storage device is also connected to the gas phase outlet of the first precipitation device.

[0157] 3. Adsorption / segmented cyclic concentration desorption of lithium ions in lithium extraction produced water

[0158] S1. reacting lime water with carbon dioxide in the lithium-extraction brine to produce bicarbonate to adjust pH, to obtain pretreated brine with a pH not less than 7.5;

[0159] Specifically, the lithium-extraction brine is introduced into a first precipitation device, and then saturated lime water and excess carbon dioxide gas are introduced into the lithium-extraction brine. The lithium-extraction brine becomes turbid first and then clear. The saturated lime water and the carbon dioxide react in the lithium-extraction brine to generate bicarbonate. The molar ratio of the bicarbonate to lithium ions in the lithium-extraction brine is controlled to be 1:1. After the lithium-extraction brine becomes clear, the lithium-extraction brine is introduced into a second precipitation device. The pH of the supernatant is detected by a pH detection device. The pH of the supernatant is not less than 7.5. The supernatant is the pretreated brine. In this process, the carbon dioxide gas that escapes from the lithium-extraction brine in the first precipitation device is recovered to a carbon dioxide storage device for storage and reinjection into the first precipitation device for preparation of bicarbonate.

[0160] S2. performing target ion adsorption and stepwise cyclic concentration desorption on the pretreated brine to obtain target ion-rich desorption liquid; wherein the target ion concentration is not less than 1 g / L.

[0161] Specifically, the pretreated brine obtained in step S1 is introduced into the liquid phase inlet of the first group of adsorption devices at a flow rate of 35 mL / min. The pretreated brine flows through the first and second groups of adsorption devices for lithium ion adsorption. After the adsorption subunit is stably operated for 1 h, the adsorption tail liquid is collected. The content of lithium ions in the adsorption tail liquid is reduced to 2 mg / L. According to the average content of lithium in the adsorption tail liquid after the adsorption subunit is stably operated for 24 h, which is 3 mg / L, it is calculated that the adsorption recovery rate of lithium is 94.3%.

[0162] Under the condition that the molar ratio of bicarbonate to lithium ions in the lithium-extraction brine is controlled to be 1:1 in step S1, when the pH of the adsorption tail liquid is detected to be less than 4, it is determined that the first and second groups of adsorption devices reach the adsorption endpoint. The first and second groups of adsorption devices are subjected to stepwise cyclic concentration desorption. The dilute hydrochloric acid contained in the acid liquid container is introduced into the liquid phase inlet of the first group of adsorption devices at a flow rate of 70 mL / min (or referred to as a desorption flow rate) to perform 1 time of surface desorption. The first-stage desorption liquid is collected in the desorption liquid container. The water in the washing liquid container is introduced into the liquid phase inlet of the first group of adsorption devices at a flow rate of 140 mL / min to perform 1 time of internal channel leaching. The leaching liquid produced by the leaching is collected in an intermediate container connected in parallel between the liquid phase outlet of the first group of adsorption devices and the liquid phase inlet of the second group of adsorption devices.

[0163] The eluate produced by the first internal channel leaching of the first group of adsorption devices in the intermediate container is combined with the dilute hydrochloric acid in the acid liquid container (the pH of the combined eluate is 1.5-2.0), and then the combined eluate is introduced into the liquid phase inlet of the second group of adsorption devices at a flow rate of 70 mL / min to perform one surface layer desorption, and the second-stage desorption eluate is collected in the desorption eluate container; and the water in the eluate container is introduced into the liquid phase inlet of the second group of adsorption devices to perform one internal channel leaching, and the eluate produced by the leaching is combined with the adsorption tail liquid;

[0164] The carbon dioxide gas produced in the process of the segmented cyclic concentration desorption is recovered from the gas phase outlets of the first and second groups of adsorption devices to the carbon dioxide storage device by the carbon dioxide conveying device, and is injected into the first precipitation device for preparation of bicarbonate.

[0165] It is determined that the average concentration of lithium ions in the desorption eluate (i.e., lithium ion-rich desorption eluate) produced by the surface layer desorption of the first and second groups of adsorption devices is 1 g / L, the concentration of lithium ions in the eluate produced by the internal channel leaching of the first and second groups of adsorption devices is 200 mg / L, and the average desorption recovery rate of lithium ions contained in the lithium ion-rich desorption eluate is 80%.

[0166] Example 3

[0167] In this embodiment, the lithium ions in the tail water after bromine extraction from the lithium ion solution obtained by sequentially subjecting produced water to oil suspension removal treatment and monovalent / divalent ion separation treatment and then further subjecting the lithium ion solution to electrolytic bromine extraction (hereinafter referred to as lithium extraction tail water) are adsorbed / desorbed by using the adsorption / segmented cyclic concentration desorption device provided by the present application and implementing the adsorption / segmented cyclic concentration desorption method provided by the present application.

[0168] 1. Component information of produced water / lithium extraction tail water

[0169] The initial components of the produced water are lithium 65 mg / L, bromine 230 mg / L, rubidium 56 mg / L, bicarbonate 150 mg / L, oil 2500 mg / L, and suspended solids 110 mg / L.

[0170] The components of the lithium extraction tail water are lithium 52 mg / L and bicarbonate 50 mg / L.

[0171] 2. Adsorption / segmented cyclic concentration desorption device information

[0172] The pretreatment unit includes the first precipitation device and the pH detection device connected thereto;

[0173] The adsorption / segmented cyclic concentration desorption unit includes the adsorption subunit and the segmented cyclic concentration desorption subunit;

[0174] The adsorption subunit includes three groups of adsorption devices, each group of adsorption devices includes three adsorption columns connected in series, and each adsorption column is filled with 1200g of titanium-based adsorbent; the three groups of adsorption devices adopt a continuous ion exchange type assembly mode; the first to third groups of adsorption devices are connected in parallel;

[0175] The segmented cyclic concentration desorption unit includes an acid liquid container, a desorption liquid container, an intermediate container and a washing liquid container, the acid liquid container contains dilute hydrochloric acid, the desorption liquid container contains desorption liquid, the intermediate container contains elution liquid, and the washing liquid container contains water;

[0176] The adsorption subunit is used as an adsorption zone, and a surface desorption zone and an internal pore elution zone are arranged; the adsorption zone is provided with three adsorption sites, the surface desorption zone is provided with three desorption sites, and the internal pore elution zone is provided with three elution sites; the first to third groups of adsorption devices are moved in a route along the adsorption sites, the desorption sites, the elution sites and the adsorption sites, and sequentially perform lithium ion adsorption, surface desorption and internal pore elution, and then perform lithium ion adsorption, so as to continuously and cyclically perform lithium ion adsorption and segmented cyclic concentration desorption;

[0177] On the adsorption site, the liquid phase inlets of the first to third groups of adsorption devices are respectively connected to the liquid phase outlet of the first precipitation device;

[0178] On the desorption site, the liquid phase inlet and outlet of the first group of adsorption devices are respectively connected to the acid liquid container and the desorption liquid container; the liquid phase inlet of the second group of adsorption devices is connected to the acid liquid container and an intermediate container containing elution liquid generated by the first internal pore elution of the first group of adsorption devices, and the liquid phase outlet of the second group of adsorption devices is connected to the desorption liquid container; the liquid phase inlet of the third group of adsorption devices is connected to the acid liquid container and an intermediate container containing elution liquid generated by the first internal pore elution of the second group of adsorption devices, and the liquid phase outlet of the third group of adsorption devices is connected to the desorption liquid container;

[0179] On the elution site, the liquid phase inlet of the first group of adsorption devices is connected to the washing liquid container, and the liquid phase outlet is connected to two intermediate containers; the liquid phase inlet of the second group of adsorption devices is connected to an intermediate container containing elution liquid generated by the second internal pore elution of the first group of adsorption devices, and the liquid phase outlet is connected to one intermediate container; the liquid phase inlet of the third group of adsorption devices is connected to the washing liquid container;

[0180] The carbon dioxide circulating unit includes a carbon dioxide storage device and a carbon dioxide conveying device; the outlet and inlet of the carbon dioxide storage device are respectively connected to the gas phase inlet of the first precipitation device and the gas phase outlet of the first to third groups of adsorption devices, and the inlet of the carbon dioxide storage device is also connected to the gas phase outlet of the first precipitation device.

[0181] 3. Adsorption / segmented cyclic concentration desorption of lithium ions in lithium-extraction water to be extracted

[0182] S1. reacting liquid alkali with carbon dioxide in the lithium-extraction water to be treated to generate bicarbonate to adjust the pH, to obtain pretreated water with a pH not less than 7.5;

[0183] Specifically, the lithium-extraction water to be treated is introduced into the first precipitation device, and then liquid alkali and excess carbon dioxide gas are introduced into the lithium-extraction water to be treated to react to generate bicarbonate, and the molar ratio of bicarbonate to lithium ions in the lithium-extraction water to be treated is controlled to be 1:1; the pH of the lithium-extraction water to be treated in the first precipitation device is detected by the pH detection device and is not less than 7.5, that is, the pretreated water is obtained; in this process, the carbon dioxide gas escaping from the lithium-extraction water in the first precipitation device is recovered to the carbon dioxide storage device for storage and reinjection into the first precipitation device for preparation of bicarbonate.

[0184] S2. target ion adsorption and stepwise cyclic concentration desorption are performed on the pretreated water to obtain target ion-rich desorption liquid; wherein the target ion concentration is not less than 1 g / L.

[0185] Specifically, the pretreated water obtained in step S1 is introduced into the liquid phase inlet of the first to third groups of adsorption devices at a flow rate of 35 mL / min on the adsorption sites, and the pretreated water flows through the first to third groups of adsorption devices for lithium ion adsorption, and the carbon dioxide generated in the adsorption process is collected in the carbon dioxide storage device for reuse in step S1; after the adsorption subunit is stably operated for 1 h, the adsorption tail liquid is collected, and the content of lithium ions in the adsorption tail liquid is reduced to 8 mg / L; according to the average content of lithium in the adsorption tail liquid after the adsorption subunit is stably operated for 24 h, which is 10 mg / L, the adsorption recovery rate of lithium ions is calculated to be 80%;

[0186] Under the condition that the molar ratio of bicarbonate to lithium ions in the lithium-extraction water to be treated is controlled to be 1:1 in step S1, when the pH of the adsorption tail liquid is detected to be <4, it is determined that the first to third groups of adsorption devices reach the adsorption endpoint, and stepwise cyclic concentration desorption is performed on the first to third groups of adsorption devices: the first group of adsorption devices is moved to the desorption position, and the dilute hydrochloric acid contained in the acid liquid container is introduced into the liquid phase inlet of the first group of adsorption devices at a flow rate of 70 mL / min (or referred to as desorption flow rate) to perform 1 time of surface desorption, and the first-stage desorption liquid is collected in the desorption liquid container; then the first group of adsorption devices is moved to the elution position, and the water in the washing liquid container is introduced into the liquid phase inlet of the first group of adsorption devices at a flow rate of 140 mL / min to perform 2 times of internal channel elution, and the elution liquid produced in each elution is collected in 2 intermediate containers, respectively.

[0187] The second group of adsorption devices is moved to the desorption position, the dilute hydrochloric acid in the acid liquid container and the first group of adsorption devices in the intermediate container are combined (the pH of the combined solution is 1.5-2.0), and then the combined solution is introduced into the liquid phase inlet of the second group of adsorption devices at a flow rate of 70 mL / min to perform one surface layer desorption, and the eluate generated is collected in the desorption liquid container; then the second group of adsorption devices is moved to the elution zone, and the second group of adsorption devices is subjected to a second internal pore elution to generate an eluate, which is introduced into the liquid phase inlet of the second group of adsorption devices at a flow rate of 140 mL / min to perform one internal pore elution, and the eluate generated is collected in an intermediate container;

[0188] The third group of adsorption devices is moved to the desorption position, the dilute hydrochloric acid in the acid liquid container and the second group of adsorption devices in the intermediate container are combined (the pH of the combined solution is 1.5-2.0), and then the combined solution is introduced into the liquid phase inlet of the third group of adsorption devices at a flow rate of 70 mL / min to perform one surface layer desorption, and the eluate generated is collected in the desorption liquid container; then the third group of adsorption devices is moved to the elution zone, and the water in the eluate container is introduced into the liquid phase inlet of the third group of adsorption devices at a flow rate of 140 mL / min to perform one internal pore elution, and the eluate generated is combined with the adsorption tail liquid;

[0189] The carbon dioxide gas generated in the process of the segmented cyclic concentration desorption is recovered by the carbon dioxide conveying device from the gas phase outlets of the first to third groups of adsorption devices to the carbon dioxide storage device for storage, and is injected into the first precipitation device for preparation of bicarbonate;

[0190] It is determined that the average concentration of lithium ions in the eluate generated by the surface layer desorption of the first to third groups of adsorption devices (i.e., the lithium ion-rich eluate) is 1.0 g / L, the concentration of lithium ions in the eluate generated by the internal pore elution of the first to third groups of adsorption devices is 150 mg / L, and the average desorption recovery rate of lithium ions contained in the lithium ion-rich eluate is 88%.

[0191] Comparative Example 1

[0192] In this comparative example, lithium ions in the tail water obtained after the bromine in the lithium ion solution obtained by sequentially subjecting produced water to oil-suspended removal treatment and monovalent / divalent ion separation treatment and then electrolyzing the bromine are subjected to adsorption / acid liquid cyclic desorption.

[0193] 1. Component information of produced water / tail water to be subjected to lithium extraction

[0194] The same as Example 1.

[0195] 2. Adsorption / desorption device information

[0196] The pre-treatment unit is the same as that in Embodiment 1;

[0197] The adsorption / acid liquid circulation desorption unit comprises an adsorption subunit and an acid liquid circulation desorption subunit;

[0198] The adsorption subunit is the same as that in Embodiment 1;

[0199] The acid liquid circulation desorption unit comprises an acid liquid container and an acid supplement container; the acid liquid container contains dilute hydrochloric acid and / or desorption liquid, and the acid supplement container contains dilute hydrochloric acid; during the desorption process, the outlet and the inlet of the acid liquid container are connected with the liquid phase inlet and the liquid phase outlet of the first to fourth groups of adsorption devices respectively to form a circulation loop; the acid supplement container is connected with the inlet of the acid liquid container;

[0200] The carbon dioxide circulation unit is the same as that in Embodiment 1.

[0201] 3. Adsorption / acid liquid circulation desorption of lithium ions in the lithium-extraction water

[0202] Step 1. The lime water reacts with carbon dioxide in the lithium-extraction water to produce bicarbonate to adjust the pH, and the pre-treatment lithium-extraction water with a pH not lower than 7.5 is obtained.

[0203] Specifically, the step S1 is the same as that in Embodiment 1, and the same pre-treatment lithium-extraction water as that in Embodiment 1 is obtained.

[0204] Step 2. Target ion adsorption and acid liquid circulation desorption are performed on the pre-treatment lithium-extraction water to obtain target ion desorption liquid.

[0205] Specifically, the adsorption step is the same as that in Embodiment 1, and the content of lithium ions in the adsorption tail liquid is reduced to 5 mg / L; according to the average content of lithium in the adsorption tail liquid after the adsorption subunit is stably operated for 24 h, the average content of lithium is 6 mg / L, and the adsorption recovery rate of lithium is calculated to be 89%.

[0206] When the pH of the adsorption tail liquid is measured to be less than 4 under the condition of controlling the ratio of the amount of substance of bicarbonate and lithium ions in the lithium-extraction-produced water to be 1:1 in step S1, it is determined that the first to fourth adsorption devices reach the adsorption end point, and the first to fourth adsorption devices are subjected to acid liquid circulation desorption: the dilute hydrochloric acid contained in the acid liquid container is introduced into the liquid phase inlet of the first adsorption device at a flow rate of 70 mL / min (or referred to as a desorption flow rate) to perform the first round of desorption, and the first round of desorption lasts for 4 h, and the desorption liquid flows out of the liquid phase outlet of the first adsorption device, and the lithium content in the desorption liquid is measured to be 200 mg / L, and the desorption recovery rate of lithium is 67%; and then the obtained desorption liquid is circulated into the first adsorption device at a desorption flow rate of 70 mL / min to perform 4 rounds of desorption, and each round of desorption lasts for 4 h, and during the desorption, dilute hydrochloric acid is supplemented to the acid liquid container through the acid supplement container to maintain the pH of the desorption liquid in the acid liquid container at 1.5-2.0; the second to fourth adsorption devices are subjected to acid liquid circulation desorption according to the same steps, and finally lithium ion desorption liquid with a lithium content of 200 mg / L is obtained, and the average desorption recovery rate of lithium in the lithium ion desorption liquid is 60%. The carbon dioxide gas generated in the acid liquid circulation desorption process is recovered from the gas phase outlets of the first to fourth adsorption devices to the carbon dioxide storage device by the carbon dioxide conveying device and stored in the carbon dioxide storage device, and is injected into the first precipitation device for preparation of bicarbonate.

[0207] Comparative Example 2

[0208] In this comparative example, lithium ions in tail water obtained by further electrolytic bromine extraction from lithium ion solution obtained by oil removal and suspension treatment and monovalent / divalent ion separation treatment of produced water (hereinafter referred to as lithium-extraction-produced water) under the condition of not introducing bicarbonate are subjected to adsorption / desorption.

[0209] 1. Components of produced water

[0210] The same as Example 1.

[0211] 2. Information of adsorption / segmented circulation and concentration desorption device under the condition of not introducing bicarbonate

[0212] No pretreatment unit and carbon dioxide circulation unit are provided;

[0213] The adsorption / segmented circulation and concentration desorption unit includes an adsorption subunit and a segmented circulation and concentration desorption subunit;

[0214] The adsorption subunit includes four groups of adsorption devices, each group of adsorption devices includes four adsorption columns connected in series, and each adsorption column is filled with 1200 g of titanium-based adsorbent; the four groups of adsorption devices are connected in parallel between the first to fourth adsorption devices; and the liquid phase inlets of the first to fourth adsorption devices are connected to introduce the lithium-extraction-produced water;

[0215] Segmented cyclic concentration desorption unit: same as example 1.

[0216] 3. Adsorbing lithium ions in the lithium-extraction water under the condition of not introducing bicarbonate ions, and performing segmented cyclic concentration desorption

[0217] Step 1. Adsorbing target ions in the lithium-extraction water, and performing segmented cyclic concentration desorption to obtain target ion desorption solution;

[0218] Specifically, the lithium-extraction water is introduced into the liquid phase inlets of the first to fourth groups of adsorption devices at a flow rate of 35 mL / min, and the lithium-extraction water flows through the first to fourth groups of adsorption devices for lithium ion adsorption. After the adsorption subunit is stably operated for 1 h, the adsorption tail liquid is collected, and the content of lithium ions in the adsorption tail liquid is measured to be reduced to 23 mg / L. According to the average content of lithium in the adsorption tail liquid after the adsorption subunit is stably operated for 24 h, the adsorption recovery rate of lithium is calculated to be 50%.

[0219] When the pH of the adsorption tail liquid is measured to be less than 4, it is determined that the first to fourth groups of adsorption devices reach the adsorption end point, and the first to fourth groups of adsorption devices are subjected to segmented cyclic concentration desorption. The specific steps are the same as those in example 1.

[0220] It is determined that the average concentration of lithium ions in the desorption solution (i.e., lithium ion-rich desorption solution) generated by surface desorption of the first to fourth groups of adsorption devices is 0.6 g / L, the concentration of lithium ions in the leaching solution generated by internal pore channel leaching of the first to third groups of adsorption devices is 50 mg / L, and the average desorption recovery rate of lithium ions contained in the lithium ion-rich desorption solution is 95%.

[0221] Result evaluation

[0222] The lithium recovery effects of the adsorption / desorption methods implemented in the above examples 1 to 3 and comparative examples 1 and 2 are arranged in table 1.

[0223] Table 1. Lithium recovery effects of various adsorption / desorption methods

[0224]

[0225] As shown in table 1, examples 1 to 3 utilize the adsorption / segmented cyclic concentration desorption device provided by the present application, and implement the adsorption / segmented cyclic concentration desorption method provided by the present application. The introduction of bicarbonate ions is combined with segmented cyclic concentration desorption, and good recovery effects of lithium in the lithium-extraction water are achieved: the adsorption recovery rate of lithium is all above 80%, and even reaches 94%, the concentration of lithium ions in the lithium ion-rich desorption solution is not less than 1 g / L, and the desorption recovery rate of lithium corresponding thereto is also all above 80%, and even reaches 95%.

[0226] Comparative Example 1 and Comparative Example 1 found that Comparative Example 1 used acid liquid circulation desorption method for lithium desorption, unable to exclude the concentration inhibition effect of lithium ions in the recycled desorption solution, affecting the lithium desorption effect, showing that the lithium ion concentration in the lithium ion-rich desorption solution decreased significantly, and the desorption recovery rate of the example was only 60%. While Example 1 uses a segmented cycle concentration desorption method for lithium desorption, combined with one surface desorption and at least one internal channel leaching, avoiding the concentration inhibition effect caused by the presence of desorbed lithium ions during the desorption process, showing obvious advantages in improving the lithium desorption recovery rate and the lithium concentration in the lithium ion-rich desorption solution, reaching a lithium desorption recovery rate of 95%, and the lithium ion concentration in the lithium ion-rich desorption solution reaching 1 g / L, and also realizing the recycling of the leaching solution produced by internal channel leaching, reducing the lithium recovery cost.

[0227] Comparative Example 2 also uses a segmented cycle concentration desorption method to desorb lithium, but it does not introduce bicarbonate to adjust the pH of the produced water before lithium adsorption, which cannot provide a suitable adsorption environment for the titanium-based adsorbent, affecting the adsorption effect of the titanium-based adsorbent on lithium, showing that the lithium adsorption recovery rate is significantly lower than that of Example 1, only 50%, and the decrease in lithium adsorption recovery rate also affects the lithium desorption recovery rate and the lithium ion concentration in the lithium ion-rich desorption solution achieved in the subsequent segmented cycle desorption stage.

[0228] It should be understood that the embodiments disclosed in the present application are not limited to the specific structure, processing steps or materials disclosed herein, but should extend to equivalent alternatives of these features understood by those skilled in the relevant art. It should also be understood that the terms used herein are for the purpose of describing specific embodiments only and are not meant to be limiting.

[0229] In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more; the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the purpose of facilitating the description of the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" and the like are only for the purpose of description and cannot be understood as indicating or implying relative importance.

[0230] In the description of the application, it is necessary to point out that, unless otherwise explicitly specified and limited, the terms "connected", "connection" should be understood broadly, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through intermediate medium. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0231] The phrase "one embodiment" or "an embodiment" as used throughout the specification means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. The appearances of the phrase "one embodiment" or "an embodiment" in various places throughout the specification are not necessarily all referring to the same embodiment.

[0232] The embodiments of the present application are given for illustrative and descriptive purposes only and are not intended to be exhaustive or to limit the application to the forms disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. Embodiments were chosen and described in order to best explain the principles of the application and its practical application, and to enable others skilled in the art to understand the application for various embodiments with various modifications as are suited to the particular use contemplated.

[0233] Although preferred embodiments of the application have been described, additional changes and modifications can be made to these embodiments by those skilled in the art once given the benefit of the present disclosure. Accordingly, the appended claims are intended to embrace all such changes and / or modifications as fall within the scope of the application. Changes and / or modifications to the embodiments according to the application made by one of ordinary skill in the art are to be encompassed by the scope of the application.

Claims

1. An adsorption / pressure swing concentration process, characterized in that, The method comprises the following steps: S1. reacting liquid alkali or lime water with carbon dioxide in produced water to produce bicarbonate to adjust pH, to obtain pretreated produced water with a pH not lower than 7.5; S2. performing target ion adsorption and stepwise cyclic concentration desorption on the pretreated produced water to obtain a target ion-rich desorption solution; wherein the target ion concentration is not lower than 1 g / L.

2. The method of claim 1, wherein, In step S2, the pretreated produced water is subjected to target ion adsorption by using an adsorption device filled with a target ion selective adsorbent.

3. The method of claim 2, wherein, In step S2, the stepwise cyclic concentration desorption comprises surface desorption and internal pore channel leaching performed in sequence in stages; First, the adsorption device that has reached the adsorption endpoint is subjected to the surface desorption once, to desorb the target ions adsorbed on the surface of the target ion selective adsorbent; Then, the adsorption device is subjected to the internal pore channel leaching at least once, to migrate the target ions remaining in the internal pore channels of the target ion selective adsorbent, to obtain the target ion-rich desorption solution.

4. The method of claim 3, wherein, In step S2, the pretreated produced water is introduced into n groups of adsorption devices to perform the target ion adsorption, to produce carbon dioxide and adsorption tail liquid, until the n groups of adsorption devices all reach the adsorption endpoint; n is an integer greater than or equal to 2; each group of adsorption devices comprises at least one adsorption column; Preferably, in the adsorption tail liquid, the concentration of the target ions is not higher than 10 mg / L.

5. The method of claim 4, wherein, In step S2, the stepwise cyclic concentration desorption is performed in the following manner: When n is 2 or an integer greater than or equal to 3, the first group of adsorption devices is subjected to the surface desorption once with acid liquid to produce a first-stage desorption solution; and the first group of adsorption devices is subjected to the internal pore channel leaching n-1 times with washing liquid, and the leaching liquid produced each time is collected separately; When n is an integer greater than or equal to 3, the acid liquid and the leaching liquid produced by the first internal pore channel leaching of the m-1th group of adsorption devices are combined to perform the surface desorption on the mth group of adsorption devices once to produce an mth-stage desorption solution; the leaching liquid produced by the second to n-(m-1)th internal pore channel leaching of the m-1th group of adsorption devices is used to perform the internal pore channel leaching on the mth group of adsorption devices n-m times, and the leaching liquid produced each time is collected separately; m is an integer from 2 to (n-1); When n is 2 or an integer greater than or equal to 3, the acid liquid and the leaching liquid produced by the first internal pore channel leaching of the n-1th group of adsorption devices are combined to perform the surface desorption on the nth group of adsorption devices once to produce an nth-stage desorption solution; the nth group of adsorption devices is subjected to the internal pore channel leaching at least once with the washing liquid, and the leaching liquid produced is combined into the adsorption tail liquid; The first to nth-stage desorption solutions are collected to obtain the target ion-rich desorption solution; The adsorption device that has completed the internal pore channel leaching continues to perform the target ion adsorption.

6. The method of claim 5, wherein, The n groups of adsorption devices are arranged in a fixed bed or a continuous ion exchange mode; n is an integer greater than or equal to 2.

7. The method according to any one of claims 3 to 6, characterized in that, The rate of the internal pore channel leaching is 1 to 5 times the rate of the surface desorption. Preferably, when the assembly mode of the n groups of adsorption devices is continuous ion exchange, the desorption rate of the surface layer is 2-4 times the adsorption rate; n is an integer ≥2.

8. The method of claim 7, wherein, The target ion is lithium ion; Preferably, the target ion selective adsorbent is titanium-based adsorbent or manganese-based adsorbent.

9. The method of claim 8, wherein, In the 2th to nth groups of adsorption devices, when any group of adsorption devices performs the surface layer desorption, the pH of the combined acid solution and the leaching solution produced by the first internal pore channel leaching of the previous group of adsorption devices is 1.5-2.0; n is an integer ≥2; and / or The pH of the acid solution is 1.5-2.0; and / or The washing solution is water.

10. The method of claim 9, wherein, The carbon dioxide produced by the target ion adsorption in the n groups of adsorption devices is collected for the reaction with liquid caustic or lime water in step S1 to produce bicarbonate to adjust the pH of the produced water and achieve carbon dioxide recycling; n is an integer ≥2. Preferably, the carbon dioxide recycling further includes collecting the carbon dioxide escaping from the produced water during the reaction and reinjecting it into the produced water.

11. An adsorption / sectional cycle enhanced desorption apparatus, characterized by, A method for implementing the adsorption / segmented cyclic concentration desorption method according to any one of claims 1-10, comprising: A pretreatment unit providing a place for the reaction of liquid caustic or lime water with carbon dioxide in produced water, so that the reaction of liquid caustic or lime water with carbon dioxide in produced water produces bicarbonate to adjust the pH and obtain pretreated produced water with a pH not lower than 7.5; An adsorption / segmented cyclic concentration desorption unit connected to the pretreatment unit, for performing target ion adsorption and segmented cyclic concentration desorption on the pretreated produced water to obtain target ion-rich desorption solution; wherein the target ion concentration is not lower than 1 g / L.

12. Use of the adsorption / segmented cyclic concentration desorption method according to any one of claims 1-10 or the adsorption / segmented cyclic concentration desorption device according to claim 11 in the utilization of produced water associated resources. Preferably, the produced water refers to chloride type produced water; and / or the content of bicarbonate in the produced water is not higher than 150 mg / L.

Images