Dechlorination method of desulfurization ionic liquid and dechlorination device of desulfurization ionic liquid

Abstract

The invention discloses a dechlorination method and a dechlorination device for a desulfurized ionic liquid, and the dechlorination method comprises the following steps: adsorbing the desulfurized ionic liquid by activated carbon to obtain a first purified liquid; the first purified liquid flows through ion exchange resin, dechlorination of the desulfurization ionic liquid is completed, and the ion exchange resin can adsorb chloride ions. By adopting the method provided by the invention, the chloride ions in the desulfurization ionic liquid can be effectively removed, and sulfate ions are basically not adsorbed, so that the mass concentration of the chloride ions contained in the desulfurization ionic liquid in a desulfurization system is kept below 400mg / L.

Description

Technical Field

[0001] The invention belongs to the technical field of chloride ion treatment, and in particular relates to a dechlorination method for desulfurized ion liquid and a dechlorination device for desulfurized ion liquid. Background Art

[0002] With the gradual promotion and large-scale application of ionic liquid desulfurization equipment in the non-ferrous metallurgical smelting industry, ionic liquid can remove sulfur dioxide from non-ferrous metallurgical smelting flue gas. However, in addition to sulfur dioxide, the flue gas also contains a small amount of sulfur trioxide, chlorine, fluorine, nitrogen oxides and other substances. During the desulfurization process using ionic liquid technology, sulfur trioxide, chlorine, fluorine, nitrogen oxides and other substances will enter the desulfurization ionic liquid and react to generate non-regenerable heat-stable salts.

[0003] At present, the desulfurization ion liquid contains sulfate ions, sodium ions and chloride ions. As the chloride ions continue to accumulate in the ion liquid, when they exceed a certain limit, they are very likely to cause corrosion of equipment and pipelines, thereby affecting the stable operation of the desulfurization device. Therefore, removing chloride ions from the ion liquid has become an urgent problem to be solved. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, one object of the present invention is to provide a method for dechlorinating a desulfurized ion liquid and a device for dechlorinating a desulfurized ion liquid, wherein the method for dechlorinating a desulfurized ion liquid can effectively remove chloride ions in the desulfurized ion liquid.

[0005] In one aspect of the present invention, the present invention provides a method for dechlorination of a desulfurized ion liquid. According to an embodiment of the present invention, the method for dechlorination of a desulfurized ion liquid comprises adsorbing the desulfurized ion liquid with activated carbon to obtain a first purified liquid; passing the first purified liquid through an ion exchange resin to complete the dechlorination of the desulfurized ion liquid, wherein the ion exchange resin can adsorb chloride ions.

[0006] According to the method of the above embodiment of the present invention, impurities such as hydrocarbons, oils and solids in the desulfurization ion liquid can be removed by adsorbing the desulfurization ion liquid through activated carbon to obtain a first purified liquid, and then the first purified liquid is passed through an ion exchange resin. The ion exchange resin can selectively adsorb chloride ions in the desulfurization ion liquid, but has basically no adsorption effect on sulfate. Therefore, the method provided in the present application can effectively remove chloride ions in the desulfurization ion liquid.

[0007] In addition, the method according to the above embodiment of the present invention may also have the following additional technical features:

[0008] In some embodiments of the present invention, the ion exchange resin includes at least one of -CONH2 and -OH. Thus, chloride ions can be selectively adsorbed, while sulfate radicals have little adsorption effect, which is beneficial to remove chloride ions in the desulfurized ion solution.

[0009] In some embodiments of the present invention, the ion exchange resin includes an acrylic acid anion exchange resin, thereby selectively adsorbing chloride ions while having little adsorption effect on sulfate, which is beneficial to remove chloride ions in the desulfurized ion solution.

[0010] In some embodiments of the present invention, the molar ratio of the groups capable of adsorbing chloride ions in the ion exchange resin is (5-7):(3-5). Thus, the chloride ions in the desulfurized ion solution can be effectively removed.

[0011] In some embodiments of the present invention, the pore size of the ion exchange resin is 100nm-200nm, so that chloride ions can be selectively adsorbed, while sulfate ions have little adsorption effect, which is beneficial to remove chloride ions in the desulfurized ion liquid.

[0012] In some embodiments of the present invention, the first purified liquid flows through the ion exchange resin at a temperature of 5° C. to 50° C. This is beneficial for removing chloride ions in the desulfurized ion liquid.

[0013] In some embodiments of the present invention, the first purified liquid flows through the ion exchange resin at a pH value of 4-15, thereby facilitating the removal of chloride ions in the desulfurized ion liquid.

[0014] In some embodiments of the present invention, when the first purified liquid flows through the ion exchange resin, the flow rate is 3m 3 -5m 3 This is beneficial for removing chloride ions in the desulfurization ion liquid.

[0015] In some embodiments of the present invention, the first purified liquid flows through the ion exchange resin for 18 minutes to 30 minutes, thereby facilitating the removal of chloride ions in the desulfurized ion liquid.

[0016] In some embodiments of the present invention, after the first purified liquid is passed through the ion exchange resin to complete the dechlorination of the desulfurized ion liquid, the step further includes flushing the ion exchange resin and regenerating the ion exchange resin that adsorbs chloride ions. Thus, the ion exchange resin can be recycled repeatedly, so that the resin can accommodate more chloride ions, and the chloride ions can be effectively removed after multiple cycles. The number of cycles can be set as needed, and the chloride ions in the desulfurized ion liquid can be effectively removed.

[0017] In another aspect of the present invention, the present invention proposes a device for removing chlorine from a desulfurized ion liquid. According to an embodiment of the present invention, the device includes an activated carbon adsorption device and an ion exchange column, wherein the activated carbon adsorption device is used to adsorb impurities in the desulfurized ion liquid; the ion exchange column is connected to the activated carbon adsorption device and is arranged downstream of the activated carbon adsorption device, and the ion exchange resin in the ion exchange column can adsorb chloride ions. Thus, chloride ions can be selectively adsorbed, while sulfate radicals have little adsorption effect, and chloride ions in the desulfurized ion liquid can be effectively removed.

[0018] In some embodiments of the present invention, the device further comprises a flushing device and a regeneration device, wherein the washing device is connected to the ion exchange column and is used to wash the ion exchange column; the regeneration device is connected to the ion exchange column and is used to regenerate the ion exchange resin that adsorbs chloride ions. Thus, the ion exchange resin can be repeatedly recycled and can effectively remove chloride ions in the desulfurization ion liquid.

[0019] In some embodiments of the present invention, the ion exchange resin includes at least one of -CONH2 and -OH. Thus, the ion exchange resin can effectively and selectively adsorb chloride ions, but has little adsorption effect on sulfate, and can effectively remove chloride ions in the desulfurized ion solution.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0022] Figure 1 A flow chart of a dechlorination method of a desulfurized ion liquid according to an embodiment of the present invention is shown;

[0023] Figure 2 A flow chart showing the removal of chloride ions by desulfurized ion liquid in an embodiment of the present invention is shown;

[0024] Figure 3 The flow chart of the desulfurization ion liquid recovery and washing according to the embodiment of the present invention is shown;

[0025] Figure 4 A flow chart showing the circulation of regeneration reagent (alkaline solution) to flush the ion exchange column in an embodiment of the present invention is shown;

[0026] Figure 5 A flow chart showing the soaking of an ion exchange column with a regeneration agent (alkaline solution) and the discharge of the regeneration agent according to an embodiment of the present invention is shown;

[0027] Figure 6The washing flow chart after the regeneration of the ion exchange column in the embodiment of the present application is shown.

[0028] Reference numerals:

[0029] Activated carbon adsorption device 1, ion exchange column 2, regeneration device 3. DETAILED DESCRIPTION

[0030] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0031] Chloride ions are perfectly miscible with most chemical elements and are difficult to remove by conventional chemical reactions to generate precipitation. The ionic liquid used in the desulfurization system is relatively expensive and it is not economically feasible to replace the entire system with waste. Therefore, it is necessary to seek a new ionic liquid purification and dechlorination process that can not only remove the chloride ions in the ionic liquid to a lower level, but also realize the recycling and regeneration of the ionic liquid, thereby ensuring the stable operation of the ionic liquid desulfurization system.

[0032] In one aspect of the present invention, the present invention provides a method for dechlorinating a desulfurized ion liquid. According to an embodiment of the present invention, the method for dechlorinating a desulfurized ion liquid comprises the following steps:

[0033] S100: The desulfurized ion liquid is adsorbed by activated carbon.

[0034] In this step, the desulfurized ion liquid from the desulfurization system is subjected to activated carbon adsorption to obtain a first purified liquid.

[0035] It should be noted that the ionic liquid is an aqueous solution composed mainly of organic cations and inorganic anions, with a small amount of activators, antioxidants and corrosion inhibitors added. No harmful gases that pollute the atmosphere will be generated during use. The ionic liquid absorbs sulfur dioxide at room temperature and regenerates the sulfur dioxide in the ionic liquid at high temperature, thereby achieving the purpose of removing and recovering sulfur dioxide in flue gas. The ionic liquid purifies the sintering flue gas in the sintering process, and after desorption, the desulfurization ionic liquid containing impurities such as solid suspended matter, sulfate ions and chloride ions is obtained. In this case, the desulfurization ionic liquid containing sulfate ions and chloride ions can also contain impurities such as solid suspended matter. Therefore, before dechlorination, the present invention firstly adsorbs the desulfurization ionic liquid on activated carbon, which has the functions of removing large suspended matter, including impurities such as solid particles; secondly, as a pretreatment before resin adsorption, the solution is filtered and adsorbed by an activated carbon adsorption tank, and then enters the subsequent ion exchange resin, which is conducive to improving the efficiency of dechlorination. The impurities usually include hydrocarbons, oils, solid particles, etc. The function of activated carbon adsorption is mainly to remove suspended matter, and the concentrations of sulfate ions and chloride ions will basically not change.

[0036] S200: passing the first purified liquid through an ion exchange resin to complete the dechlorination of the desulfurized ion liquid, wherein the ion exchange resin can adsorb chloride ions.

[0037] In this step, the first purified liquid obtained above is subjected to ion exchange resin. The ion exchange resin can selectively adsorb chloride ions in the first purified liquid, but has little adsorption effect on sulfate ions, thereby completing the dechlorination of the desulfurized ion liquid.

[0038] It should be noted that ion exchange resins are composed of three parts: an insoluble three-dimensional network polymer skeleton, ionic functional groups connected to the skeleton, and exchangeable ion pores with opposite charges on the functional groups. Among them, on the polymer skeleton, many exchange groups are chemically bonded, and these exchange groups are composed of two parts: a fixed part and a mobile part. The fixed part of the exchange group is bound to the polymer skeleton and cannot move freely, so it is called a fixed ion; the mobile part of the exchange group is an ion with the opposite sign to the fixed ion bonded by an ionic bond, called a counterion or exchangeable ion. Counterions can dissociate into free-moving ions in the solution, and under certain conditions, they can undergo exchange reactions with other counterions of the same electrical properties.

[0039] According to some embodiments of the present invention, the ion exchange resin includes -CONH2 and -OH. The ion exchange resin contains -CONH2 groups and -OH groups, wherein the -CONH2 group is a polar group that can control the performance of the ion exchange resin, that is, the amine group in the -CONH2 group is a basic group that is easy to generate OH in the desulfurized ion solution. -, while the anions (Cl - ) are transferred to the ion exchange resin, and for large molecular weight ions such as sulfate, since they cannot pass through the small diameter pores, there is basically no adsorption effect, and the OH on the ion exchange resin - The -OH groups on the ion exchange resin are exchangeable ions that can directly react with anions (Cl - ) for exchange. Thus, the chloride ions in the desulfurized ion liquid can be effectively removed.

[0040] It should be noted that the polar group is an organic part in which the electron distribution in the molecule does not produce a significant electric dipole moment. Since water is polar, according to the principle of like dissolves like, polar groups are usually soluble in water. Therefore, the -CONH2 group of the present application is soluble in water to generate OH - .

[0041] According to some embodiments of the present invention, the ion exchange resin includes an acrylic anion exchange resin. The acrylic anion exchange resin is a macroporous methyl propionate copolymer cross-linked polymer, which is a polyamine-based weakly alkaline ion exchange resin obtained by aminolysis of polyethylene polyamines. It has the characteristics of large exchange capacity, small volume change, high mechanical strength, good chemical stability, anti-pollution, excellent antioxidant performance, fast exchange speed, etc. Therefore, the use of acrylic anion exchange resin can effectively remove chloride ions in the desulfurized ion solution.

[0042] According to some embodiments of the present invention, in the ion exchange resin, the molar ratio of the group that can adsorb chloride ions is (5-7): (3-5). For example, the molar ratio of the group that can adsorb chloride ions can be 5:3, 5:5, 6:5, 6:7, 6:4, etc. If the content of the group that can adsorb chloride ions is too low, the adsorption of chloride ions will not be thorough, thereby reducing the removal efficiency of chloride ions; if the content of the group that can adsorb chloride ions is too much, the alkalinity of the ion exchange resin will be too large, thereby affecting the effect of removing chloride ions. Thus, the molar ratio of the group that can adsorb chloride ions is limited to the above range, which can effectively remove the chloride ions in the desulfurization ion liquid.

[0043] According to some embodiments of the present invention, the mass ratio of sulfate ions to chloride ions in the first purified liquid is (20-100):1, for example, the mass ratio of sulfate ions to chloride ions can be 20:1, 40:1, 60:1, 80:1, 100:1, etc. The mass ratio of sulfate ions to chloride ions in the first purified liquid is limited to the above range, and the ion exchange resin provided in the present application has strong selective adsorption and strong resistance to organic pollution for chloride ions therein. As a result, chloride ions can be selectively adsorbed, thereby effectively removing chloride ions in the desulfurized ion liquid.

[0044] According to some embodiments of the present invention, the pore size of the ion exchange resin is 100nm-200nm, for example, the pore size of the ion exchange resin can be 100nm, 120nm, 140nm, 160nm, 180nm, 200nm, etc. By limiting the pore diameter of the ion exchange resin to the above range, chloride ions can be preferentially adsorbed, while large molecular weight ions such as sulfate cannot pass through small diameter pores, so there is basically no adsorption effect, thereby removing chloride ions in the desulfurized ion solution.

[0045] According to some embodiments of the present invention, the first purified liquid flows through the ion exchange resin at a temperature of 5°C-50°C. For example, the temperature of the first purified liquid flowing through the ion exchange resin may be 5°C, 10°C, 15°C, 20°C, 30°C, 40°C, 50°C, etc. When the temperature of the first purified liquid flowing through the ion exchange resin is too low, the exchange rate of chloride ions will be reduced; when the temperature of the first purified liquid flowing through the ion exchange resin is too high, the internal structure of the ion exchange resin may be damaged, thereby affecting the selective adsorption performance of the ion exchange resin for chloride ions. Therefore, limiting the temperature of the first purified liquid flowing through the ion exchange resin to the above range can effectively remove chloride ions in the desulfurization ion liquid.

[0046] According to some embodiments of the present invention, the first purified liquid flows through the ion exchange resin at a pH value of 4-15. For example, the pH may be 4, 6, 8, 10, 12, 14, 15, etc. If the pH is too low, the content of -OH groups in the ion exchange resin will be too low, so that the adsorption of chloride ions is insufficient, thereby affecting the removal efficiency of chloride ions; if the pH is too high, the internal structure of the ion exchange resin may be destroyed, thereby affecting the selective adsorption performance of the ion exchange resin for chloride ions. Therefore, limiting the pH within the above range can effectively remove chloride ions in the desulfurization ion liquid.

[0047] According to some embodiments of the present invention, when the first purified liquid flows through the ion exchange resin, the flow rate is 3m 3 -5m 3 For example, the flow rate can be 3m 3 , 3.5m 3 , 4m 3 , 4.5m 3 , 5m 3 By limiting the flow rate within the above range, the first purified liquid can be fully contacted with the ion exchange resin, thereby effectively adsorbing the chloride ions in the first purified liquid and further removing the chloride ions in the desulfurization ion liquid.

[0048] According to some embodiments of the present invention, the time for the first purified liquid to flow through the ion exchange resin is 18min-30min. For example, the time for the first purified liquid to flow through the ion exchange resin can be 18min, 20min, 22min, 26min, 28min, 30min, etc. If the time for the first purified liquid to flow through the ion exchange resin is too short, the adsorption of chloride ions by the ion exchange resin will be insufficient, thereby affecting the removal effect of chloride ions in the desulfurization ion liquid; if the time for the first purified liquid to flow through the ion exchange resin is too long, the time cost of the dechlorination operation will be increased. Therefore, limiting the time for the first purified liquid to flow through the ion exchange resin within the above range is conducive to the selective adsorption of chloride ions by the ion exchange resin, and can effectively remove chloride ions in the desulfurization ion liquid.

[0049] According to some embodiments of the present invention, after the first purified liquid is passed through the ion exchange resin to complete the dechlorination of the desulfurization ion liquid, the step further includes flushing the ion exchange resin and regenerating the ion exchange resin that absorbs chloride ions. By flushing the ion exchange resin, the desulfurization ion liquid or other liquid impurities remaining on the ion exchange resin can be washed, thereby avoiding the waste of the desulfurization ion liquid and ensuring the performance of the ion exchange resin; by regenerating the ion exchange resin that absorbs chloride ions, the ion exchange resin can be recycled, thereby reducing the cost of removing chloride ions.

[0050] There is no special limitation on the flushing agent selected for flushing the ion exchange resin. For example, the flushing agent can be pure water or desalted water. According to a specific embodiment of the present invention, the present application uses desalted water to flush the ion exchange resin, which can effectively wash away the desulfurized ion liquid remaining on the ion exchange resin without introducing other impurity ions into the desulfurized ion liquid, thereby effectively recovering the excess desulfurized ion liquid and ensuring the performance of the ion exchange resin. It should be noted that desalted water refers to water that does not contain strong electrolytes (salts) and has a low conductivity of about 1.0μs / cm-10.0μs / cm.

[0051] According to some embodiments of the present invention, the flushing of the ion exchange resin includes the recovery flushing of the desulfurization ion liquid, wherein the recovery flushing of the desulfurization ion liquid is performed after the desulfurization ion liquid completes the adsorption of chloride ions, and the purpose is to flush away the desulfurization ion liquid remaining on the ion exchange resin, recycle the desulfurization ion liquid, avoid the waste of the desulfurization ion liquid, and the desulfurization ion liquid obtained after flushing is circulated back to the desulfurization system.

[0052] The recovery and flushing method of the desulfurized ion liquid is not particularly limited in the present application. In a specific embodiment of the present application, the recovery and flushing of the desulfurized ion liquid includes a first flush, an immersion and a second flush in sequence. Specifically, after the desulfurized ion liquid completes the exchange of chloride ions through the ion exchange resin, the desalted water is introduced into the ion exchange resin for the first flush. The first flush can recover most of the desulfurized ion liquid remaining on the ion exchange resin for recycling. The liquid inlet volume of the first flush is 3m 3 -5m 3 For example, the liquid inlet volume can be 3m 3 , 3.5m 3 , 4m 3 , 4.5m 3 , 5m 3 etc.; the time for the first flushing is 10min-15min. For example, the time for the first flushing can be 10min, 11min, 12min, 13min, 14min, 15min, etc.

[0053] Furthermore, the ion exchange resin is soaked in desalted water to further recover the desulfurized ion liquid remaining on the ion exchange resin, wherein the soaking time is 10 min-15 min. For example, the soaking time can be 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, etc.

[0054] Finally, the ion exchange resin is rinsed for the second time with desalted water to avoid the waste of desulfurized ion liquid. 3 -2m 3 For example, the liquid inlet volume can be 1m 3 , 1.2m 3 , 1.4m 3 , 1.6m 3 , 2m 3 etc.; the time for the second flushing is 10min-15min, for example, the time can be 10min, 11min, 12min, 13min, 14min, 15min, etc.

[0055] The present application does not specifically limit the method for regenerating the ion exchange resin that adsorbs chloride ions. In a specific embodiment of the present application, an alkali solution is used as a regeneration reagent to regenerate the ion exchange resin. - It can exchange with the chloride ions adsorbed on the ion exchange resin, making OH - It can stay in the ion exchange resin and be used for the next chloride ion adsorption. However, the exchanged chloride ions will stay in the alkali solution and be discharged along with the alkali solution.

[0056] Specifically, after the ion exchange resin is rinsed for the second time with desalted water, the prepared regeneration reagent (alkali solution, sodium hydroxide solution with a mass concentration of 1%-3% in the embodiment of the present application) is introduced into the ion exchange resin to rinse the ion exchange resin. The amount of sodium hydroxide solution for rinsing is 1m 3 -2m 3 For example, the liquid inlet volume can be 1m 3 , 1.2m 3 , 1.4m 3 , 1.6m 3 , 2m 3 The washing time of the sodium hydroxide solution is 10-15 minutes, for example, the time can be 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, etc. The washed sodium hydroxide solution is recovered for the next washing, and the sodium hydroxide solution is used for cyclic washing at least three times. In this way, the chloride ions adsorbed on the ion exchange resin can be washed away, thereby realizing the regeneration of the ion exchange resin.

[0057] Subsequently, the rinsed ion exchange resin is soaked in a sodium hydroxide solution for 10-15 minutes, for example, the time may be 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, etc., the soaked sodium hydroxide solution is recovered, and when the pH value of the sodium hydroxide solution is 8-10, for example, the pH value may be 8, 8.5, 9, 9.5, 10, etc., it is discharged, thereby further washing away the chloride ions adsorbed on the ion exchange resin, avoiding excessive waste of sodium hydroxide regeneration reagent, and saving the cost of the regeneration reagent.

[0058] According to some embodiments of the present invention, the regeneration of the ion exchange resin that adsorbs chloride ions also includes regeneration flushing of the ion exchange resin. The regeneration flushing of the ion exchange resin is performed after the ion exchange resin is regenerated, and the purpose is to flush away the regeneration reagent remaining on the ion exchange resin to prevent the regeneration reagent from affecting the performance of the ion exchange resin in selectively adsorbing chloride ions, thereby facilitating the recycling of the ion exchange resin.

[0059] The regeneration and flushing of the ion exchange resin is not particularly limited in the present application. In a specific embodiment of the present application, the post-regeneration flushing of the ion exchange resin includes a third flushing, a regeneration agent soaking and a fourth flushing in sequence. Specifically, after the ion exchange resin is regenerated with an alkali solution, the ion exchange resin is flushed with desalted water for the third time, and the liquid inlet volume of the third flushing is 3m 3 -5m 3 For example, the liquid inlet volume can be 3m 3 , 3.5m 3, 4m 3 , 4.5m 3 , 5m 3 etc.; the third flushing time is 10min-15min, for example, the flushing time can be 10min, 11min, 12min, 13min, 14min, 15min, etc., and the flushing liquid is discharged.

[0060] Subsequently, the ion exchange resin is soaked in a regeneration agent with desalted water for 10-15 minutes, for example, the soaking time can be 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, etc., and the soaked liquid is discharged; finally, the ion exchange resin is rinsed for the fourth time with desalted water, and the liquid inlet volume for the fourth rinse is 1m 3 -2m 3 For example, the liquid inlet volume can be 1m 3 , 1.2m 3 , 1.4m 3 , 1.6m 3 , 2m 3 etc.; the fourth flushing time is 10min-15min, for example, the time can be 10min, 11min, 12min, 13min, 14min, 15min, etc. Therefore, the above-mentioned washing method can effectively wash away the regeneration reagent remaining on the ion exchange resin, thereby ensuring the ability of the ion exchange resin to adsorb chloride ions.

[0061] According to an embodiment of the present invention, the method provided by the present application is adopted, firstly activated carbon is used for adsorption, and then an ion exchange resin that can selectively adsorb chloride ions is selected to adsorb the chloride ions in the desulfurized ion liquid, and the sulfate radical in the desulfurized ion liquid is basically not adsorbed, and the purified desulfurized ion liquid is continued to be subjected to the desulfurization operation, and the ion exchange resin after dechlorination can be regenerated and repeatedly recycled. This method does not need to be desulfurized first and then dechlorinated, and the desulfurized ion liquid after activated carbon adsorption can be directly removed from the chloride ions through the ion exchange resin, which can reduce the process of the desulfurized ion liquid and reduce the time cost of the dechlorination operation. Thus, the method has a simple process, is easy to operate and control, and can effectively remove the chloride ions in the desulfurized ion liquid.

[0062] In another aspect of the present invention, the present invention provides a device for removing chlorine from a desulfurized ion liquid. Figure 1 It is understood that the device includes an activated carbon adsorption device 1 and an ion exchange column 2, wherein the activated carbon adsorption device 1 is used to adsorb impurities in the desulfurized ionic liquid; the ion exchange column 2 is connected to the activated carbon adsorption device 1 and is arranged downstream of the activated carbon adsorption device 1, and the ion exchange resin in the ion exchange column 2 can adsorb chloride ions.

[0063] According to an embodiment of the present invention, please refer to Figure 1 , the desulfurized ion liquid from the desulfurization system first passes through the activated carbon adsorption device 1, pre-treats the desulfurized ion liquid before resin adsorption, and then enters the subsequent ion exchange column 2 for adsorption of chloride ions, which is beneficial to improving the dechlorination effect, and the activated carbon adsorption device 1 can adsorb impurities in the desulfurized ion liquid, such as hydrocarbons, oils, solid particles, etc. Since the ion exchange column 2 is connected to the activated carbon adsorption device 1 and is located downstream of the activated carbon adsorption device 1, it is beneficial to shorten the time for the desulfurized ion liquid after the activated carbon adsorption to perform ion exchange, thereby improving the efficiency of dechlorination. In addition, the ion exchange resin in the ion exchange column 2 can adsorb chloride ions, but has basically no adsorption effect on sulfate ions. As a result, the chloride ions in the desulfurized ion liquid can be selectively adsorbed, thereby preventing the chloride ions from corroding the desulfurization system.

[0064] According to some embodiments of the present invention, the device further comprises a washing device and a regeneration device 3, wherein the washing device is connected to the ion exchange column 2 and is used for washing the ion exchange column; the regeneration device 3 is connected to the ion exchange column 2 and is used for regenerating the ion exchange resin that adsorbs chloride ions.

[0065] According to an embodiment of the present invention, a washing device is connected to the ion exchange column 2, so that the washing liquid (desalted water) in the washing device can wash the ion exchange column 2, thereby ensuring the selective adsorption of chloride ions by the ion exchange column 2, such as: after the ion exchange column 2 is ion exchanged with the desulfurized ion liquid, a small amount of desulfurized ion liquid will remain in the ion exchange resin, which will cause waste of the desulfurized ion liquid and reduce the performance of the ion exchange column. Therefore, by washing the ion exchange column 2 with the washing liquid (desalted water) in the washing device and returning the washed desulfurized ion liquid to the desulfurization system, the waste of the desulfurized ion liquid can be avoided and the performance of the ion exchange column 2 can be ensured. In order to promote the recycling of the ion exchange column 2 that adsorbs chloride ions, the regeneration device 3 is connected to the ion exchange column 2, and the regeneration reagent (alkaline solution) contained in the regeneration device 3 can contact the ion exchange column 2 that adsorbs chloride ions, and can transfer the chloride ions adsorbed in the ion exchange column 2 to the regeneration reagent, thereby promoting the regeneration of the ion exchange column 2 and enabling the next adsorption of chloride ions.

[0066] According to some embodiments of the present invention, the ion exchange resin includes -CONH2 and -OH. The ion exchange resin contains -CONH2 groups and -OH groups, which can preferentially adsorb chloride ions (Cl - ), but has little adsorption effect on sulfate ions, so there is no need to remove sulfate ions first, saving process.

[0067] According to some embodiments of the present invention, the dechlorination device provided in the present application can be used in conjunction with a desulfurization system or can be used alone. In a specific embodiment of the present application, the dechlorination device is used in conjunction with a desulfurization system, that is, in the desulfurization system, a desulfurization ion liquid circulation line is bypassed and diverted by about 5%-10% of the flow rate into the dechlorination device for purification and dechlorination. After dechlorination is completed, the desulfurization ion liquid is returned to the desulfurization system, and the operation frequency of the dechlorination device is adjusted according to the level of mass concentration of chloride ions in the ion liquid in the desulfurization system. For example, when the mass concentration of chloride ions is 1000 mg / L, the dechlorination device needs to operate 7-15 times, thereby ensuring that the mass concentration of chloride ions in the desulfurization ion liquid is within the corrosion resistance range of the equipment, avoiding the problem of excessive one-time investment and low utilization rate of the device due to full-flow dechlorination.

[0068] According to an embodiment of the present invention, please refer to Figure 2 , Figure 2 In the dechlorination process, the direction indicated by the arrow in the figure is the flow direction of the desulfurization ion liquid. The desulfurization ion liquid from the desulfurization system bypass first enters the activated carbon adsorption device 1 to remove impurities such as hydrocarbons, oils, and solid particles, and then enters the ion exchange column 2 for chloride ion adsorption. The desulfurization ion liquid after the chloride ion adsorption is returned to the desulfurization system.

[0069] Figure 3 This is the flushing process after dechlorination. The direction indicated by the arrow in the figure is the flow direction of the desalted water. The desalted water in the washing device is then introduced into the ion exchange column 2 to wash the ion exchange column 2. Specifically, the ion exchange column 2 is flushed for the first time with the desalted water, and the flushed liquid is returned to the desulfurization system. The ion exchange column 2 is then soaked with the desalted water, and the soaked liquid is returned to the desulfurization system. Finally, the ion exchange column 2 is flushed for the second time with the desalted water, and the flushed liquid is returned to the desulfurization system.

[0070] Further, Figure 4 and Figure 5 This is the regeneration process of the ion exchange column. The arrow in the figure indicates the flow direction of the alkali solution. Please refer to Figure 4 , introduce the regeneration reagent (alkaline solution) in the regeneration device 3 into the rinsed ion exchange column 2 to regenerate the ion exchange column 2. Specifically, add sodium hydroxide with a mass concentration of 1%-3% as a regeneration reagent into the regeneration device 3, rinse the ion exchange column 2 with the sodium hydroxide solution, return the rinsed solution to the regeneration device, and repeat the rinse operation with the sodium hydroxide solution at least three times.

[0071] Afterwards, see Figure 5 , soak the ion exchange column 2 with sodium hydroxide solution, and return the soaked solution to the regeneration device 3 (corresponding to Figure 5The process (1)→(2)→(3)→(4)→(5)→(6)→(7)→(8)→(9)) in the above table is followed, and the pH of the sodium hydroxide solution is tested. If the pH is between 8 and 10, the liquid is discharged into the wastewater system (corresponding to Figure 5 In the process a→b→c→d→e→f→g→h), if the pH is greater than 10, the sodium hydroxide can be recycled and continued to be used for regeneration of the ion exchange column.

[0072] at last, Figure 6 This is the flushing process after the ion exchange column is regenerated. The arrow in the figure indicates the flow direction of the desalted water. Please refer to Figure 6 , the washing liquid in the washing device is introduced into the regenerated ion exchange column 2, and the ion exchange column 2 is washed again. Specifically, the washing device is equipped with desalted water as the washing liquid. First, the ion exchange column 2 is rinsed for the third time with the desalted water, and the washed liquid is discharged from the wastewater system. Then, the ion exchange column 2 is soaked with desalted water, and the soaked liquid is discharged from the wastewater system. Finally, the ion exchange column 2 is rinsed for the fourth time, and the rinsed solution is discharged from the wastewater system (corresponding to Figure 6 The process A→B→C→D→E→F→G).

[0073] Thus, by using the dechlorination device provided by the present application, the chloride ion concentration in the desulfurization system can be quickly reduced to the corrosion resistance range of the desulfurization device through short-term continuous operation, and the operation frequency can be gradually reduced in the later stage, so as to maintain the normal level of chloride ion concentration. The process is simple, easy to operate and control, occupies a small area, has a high degree of matching with the ionic liquid desulfurization system, can realize unattended automatic operation, no waste residue output, and only produces a small amount of wastewater. Whether it is a supporting construction with the ionic liquid desulfurization system or a later transformation and addition, it has obvious advantages and operability.

[0074] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. If no specific techniques or conditions are specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used that do not specify the manufacturer are all conventional products that can be obtained commercially.

[0075] Example 1

[0076] (1) The desulfurized ion liquid is adsorbed by activated carbon to obtain a first purified liquid, wherein the mass ratio of sulfate ions to chloride ions in the first purified liquid is 50 / 1.

[0077] (2) The first purified liquid is sent into an acrylic anion exchange resin with a pore size of 150 nm. The flow rate of the first purified liquid is 4 m 3, the chloride ion adsorption is carried out under the conditions of temperature of 25°C and pH of 5, the ion exchange time is 30 minutes, the chloride ion adsorption is completed, the second purified liquid is obtained, and the second purified liquid is recovered and returned to the desulfurization system.

[0078] The dechlorination method of Example 2-11 is the same as that of Example 1 except for different process parameters (see Table 1).

[0079] The process parameters of the dechlorination method of Examples 1-11 of the present application are shown in Table 1.

[0080] Table 1 Process parameters of Examples 1-11

[0081]

[0082] Comparative Example 1

[0083] The acrylic acid anion exchange resin in Example 1 was replaced by commercially available D-318 acrylic acid macroporous weakly basic anion exchange resin, and other experimental parameters were kept the same as those in Example 1.

[0084] Testing and analysis

[0085] Under the same conditions, the chloride ion concentration of the desulfurized ion solution obtained by purification in the above Examples 1-11 and Comparative Example 1 was measured and the dechlorination efficiency was calculated. The specific test calculation method is as follows:

[0086] Determination of chloride ion concentration: In the neutral weak alkaline range (pH 6.5-10.5), potassium chromate is used as an indicator to titrate chloride with silver nitrate. Since the solubility of silver chloride is less than that of silver chromate, chloride ions are first completely precipitated, and then chromate is precipitated in the form of silver chromate, producing a brick red color, and the indicator titration endpoint is reached. The reaction of the precipitation titration is as follows:

[0087] Ag + +Cl - →AgCl↓

[0088] 2Ag + +CrO4→Ag2CrO4↓(brick red).

[0089] Dechlorination efficiency = (chloride ion concentration in the first purified liquid - chloride ion concentration in the purified desulfurized ion liquid) / chloride ion concentration in the first purified liquid × 100%.

[0090] The test results are shown in Table 2.

[0091] Table 2 Test results of Examples 1-11 and Comparative Example 1

[0092]

[0093] Combined with Table 2, it can be seen that the chlorine removal efficiency of Examples 1-11 is significantly greater than that of Comparative Example 1. Therefore, the dechlorination method provided in the present application can effectively remove chloride ions in the desulfurization ion liquid, so that the mass concentration of chloride ions contained in the desulfurization ion liquid in the desulfurization system is maintained below 400 mg / L.

[0094] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0095] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for dechlorinating a desulfurized ion liquid, characterized in that: The following steps are involved: The desulfurized ion liquid is adsorbed by activated carbon to obtain a first purified liquid; The first purified liquid is passed through an ion exchange resin to complete the dechlorination of the desulfurized ion liquid, wherein the ion exchange resin can adsorb chloride ions.

2. The method according to claim 1, characterized in that: The ion exchange resin includes at least one of -CONH2 and -OH.

3. The method according to claim 1, characterized in that The ion exchange resin includes an acrylic acid anion exchange resin.

4. The method according to claim 1, characterized in that In the ion exchange resin, the molar ratio of the groups capable of adsorbing chloride ions is (5-7):(3-5).

5. The method according to any one of claims 1 to 4, characterized in that One of the following conditions is met: The pore size of the ion exchange resin is 100nm-200nm; The first purified liquid flows through the ion exchange resin at a temperature of 5°C-50°C; The first purified liquid flows through the ion exchange resin at a pH value of 3-7.

6. The method according to any one of claims 1 to 4, characterized in that When the first purified liquid flows through the ion exchange resin, the flow rate is 3m 3 -5m 3 and / or, The time for the first purified liquid to flow through the ion exchange resin is 18 min-30 min.

7. The method according to claim 1, characterized in that After the first purified liquid is passed through the ion exchange resin to complete the dechlorination of the desulfurized ion liquid, the step further includes: Flushing of ion exchange resins and regeneration of ion exchange resins that adsorb chloride ions.

8. A dechlorination device for desulfurized ion liquid, comprising: Activated carbon adsorption device, used to adsorb impurities in the desulfurized ion liquid; The ion exchange column is communicated with the activated carbon adsorption device and is arranged downstream of the activated carbon adsorption device. The ion exchange resin in the ion exchange column can adsorb chloride ions.

9. The device according to claim 8, characterized in that The device also includes: a washing device, connected to the ion exchange column and used for washing the ion exchange column; The regeneration device is connected to the ion exchange column and is used for regenerating the ion exchange resin that adsorbs chloride ions.

10. The device according to claim 8, characterized in that The ion exchange resin includes at least one of -CONH2 and -OH.

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