Method for reviving an alcohol amine solution

Abstract

The application provides a method for reviving an alcohol amine solution. The method for reviving the alcohol amine solution comprises the following steps: performing first adsorption treatment on the alcohol amine solution to be revived by using a hydrogen phosphate removing agent to obtain a first solution and an adsorption system; performing second adsorption treatment on the first solution by using a hydroxyl ion exchange resin and a methyldiethanolamine cation exchange resin in sequence to obtain a second solution; performing second mixing treatment on the adsorption system by using an ammonium sulfate solution to obtain a third solution and a removing agent to be regenerated; performing second mixing treatment on the third solution by using a hydrogen ion exchange resin to obtain a fourth solution; and performing third mixing treatment on the second solution and the fourth solution to obtain a revived alcohol amine solution. The method for reviving the alcohol amine solution can remove the heat stable salt in the alcohol amine solution to be revived, and hardly causes loss of ammonium hydrogen phosphate in the alcohol amine solution to be revived.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of chemical separation technology, in particular to a method for reviving an alcohol amine solution. BACKGROUND

[0002] The alcohol amine method purification process refers to a process of using an alcohol amine solution for desulfurization and decarbonization. The alcohol amine method purification process is not only widely used in the purification of natural gas and refinery gas, but also often used in the synthetic ammonia industry and the industry of preparing downstream products from synthesis gas.

[0003] In the prior art, ammonium hydrogen phosphate is usually added to an N-methyldiethanolamine (MDEA) aqueous solution to reduce the pH of the MDEA aqueous solution, and the same ion effect between ammonium hydrogen phosphate and MDEA is utilized to reduce the absorption rate of CO2, thereby reducing the competitive absorption of H2S by CO2 and improving the selective absorption of H2S. However, the composite alcohol amine solution formed by MDEA and ammonium hydrogen phosphate will inevitably generate various impurities due to self-oxidation or contamination of raw gas entrainment during the purification process. These impurities include heat stable salts such as glycolate, acetate, formate, sulfate, chloride, oxalate, and thiosulfate. In actual application, heat stable salts have strong corrosive properties, which can easily cause corrosion perforation and other safety problems in the alcohol amine method purification device. Moreover, when the heat stable salts accumulate to a certain extent in the composite alcohol amine solution, the viscosity of the composite alcohol amine solution increases, which in turn increases the mass transfer rate of acid gases in the composite alcohol amine solution, resulting in a decrease in the desulfurization performance of the alcohol amine method purification device and a production quality problem of H2S content exceeding the standard in the product gas. Meanwhile, when the concentration of heat stable salts in the composite alcohol amine solution further increases, part of the heat stable salts will precipitate and block the trays in the alcohol amine method purification device, making it difficult for the alcohol amine method purification device to operate. Therefore, in order to ensure the safe operation of the alcohol amine method purification device and the quality of the product gas, it is necessary to remove the heat stable salts in the composite alcohol amine solution in time to reduce the concentration of heat stable salts in the composite alcohol amine solution to a very low concentration level.

[0004] The existing reviving methods of the alcohol amine solution include the reduced pressure distillation method, the electrodialysis method and the ion exchange method. Among them, the reduced pressure distillation method can separate the heat stable salt by using the high boiling point characteristics of the heat stable salt, but the ammonium hydrogen phosphate active agent for enhancing the H2S selective absorption in the composite alcohol amine solution is also a high boiling point substance, so the ammonium hydrogen phosphate active agent is also easily separated in the process of separating the heat stable salt; the electrodialysis method can make the anions of the heat stable salt in the composite alcohol amine solution move to the anode by using the electric field effect, and make the cations of the heat stable salt in the composite alcohol amine solution move to the cathode by using the cation exchange membrane in the electrodialysis device, so as to realize the purpose of removing the anions and cations of the heat stable salt in the composite alcohol amine solution, but the ammonium hydrogen phosphate will also be decomposed into anions and cations in the electric field and thus removed; the ion exchange method can remove the anions of the heat stable salt such as chloride, sulfate, thiosulfate, formate, acetate and oxalate in the composite alcohol amine solution to a low concentration level by using the anion exchange resin, but the hydrogen phosphate ions can also be removed. In summary, the existing reviving methods of the alcohol amine solution not only remove the heat stable salt in the composite alcohol amine solution, but also remove the ammonium hydrogen phosphate active agent for enhancing the H2S selective absorption, so that the obtained reviving alcohol amine solution has low H2S selective absorption, and it is difficult to obtain product gas with qualified H2S content.

[0005] Therefore, it is urgent to provide a reviving method of alcohol amine solution which can remove the heat stable salt and hardly lose the ammonium hydrogen phosphate. SUMMARY

[0006] The present application provides a reviving method of alcohol amine solution which can remove the heat stable salt in the alcohol amine solution to be revived and hardly lose the ammonium hydrogen phosphate in the alcohol amine solution to be revived.

[0007] The present application provides a reviving method of alcohol amine solution, comprising the following steps:

[0008] The alcohol amine solution to be revived is subjected to first adsorption treatment by using the hydrogen phosphate removal agent, to obtain a first solution and an adsorption system;

[0009] The first solution is subjected to second adsorption treatment by using the hydroxyl ion exchange resin and the methyldiethanolamine cation exchange resin in sequence, to obtain a second solution;

[0010] The ammonium sulfate solution is subjected to first mixing treatment with the adsorption system, to obtain a third solution and a removal agent to be regenerated;

[0011] The hydrogen ion exchange resin is subjected to second mixing treatment with the third solution, to obtain a fourth solution;

[0012] The second solution and the fourth solution are subjected to third mixing treatment, to obtain a reviving alcohol amine solution.

[0013] The reviving method of the alcohol amine solution as described above, wherein the hydrogen phosphate removing agent is [Ca (2～3) Sc(OH) (6～8) ]OH.

[0014] The reviving method of the alcohol amine solution as described above, wherein the mass m0 of the alcohol amine solution to be revived, the mass percentage content p0 of the hydrogen phosphate in the alcohol amine solution to be revived, the mass m1 of the hydrogen phosphate removing agent, and the adsorption mass m2 per unit mass of the hydrogen phosphate removing agent satisfy the following relationship:

[0015] m0*p0≤m1*m2*90%.

[0016] The reviving method of the alcohol amine solution as described above, wherein the alcohol amine solution to be revived flows through the hydrogen phosphate removing agent, so as to realize the first adsorption treatment of the hydrogen phosphate removing agent to the alcohol amine solution to be revived.

[0017] The volume space velocity of the alcohol amine solution to be revived flowing through the hydrogen phosphate removing agent is less than or equal to 5h -1 .

[0018] The reviving method of the alcohol amine solution as described above, wherein the volume V1 of the ammonium sulfate solution, the volume molar concentration C1 of the ammonium sulfate solution, the volume V0 of the alcohol amine solution to be revived, and the volume molar concentration C0 of the hydrogen phosphate in the alcohol amine solution to be revived satisfy the following relationship:

[0019] V1*C1=1.5V0*C0: and / or,

[0020] The ammonium sulfate solution flows through the adsorption system, so as to realize the first mixing treatment of the ammonium sulfate solution and the adsorption system.

[0021] The volume space velocity of the ammonium sulfate solution flowing through the adsorption system is less than or equal to 4h -1 .

[0022] The reviving method of the alcohol amine solution as described above, wherein the volume molar concentration of the ammonium sulfate solution is 1.2-2.3 mol / L.

[0023] The reviving method of the alcohol amine solution as described above, wherein the reviving method of the alcohol amine solution further comprises: regenerating the removing agent to be regenerated by using a regeneration liquid to obtain a regenerated removing agent.

[0024] The regeneration liquid is selected from a sodium hydroxide aqueous solution and / or a potassium hydroxide aqueous solution.

[0025] The reviving method of the alcohol amine solution as described above, wherein the concentration of the hydroxyl ions in the regenerating solution is 1.3-1.5 mol / L.

[0026] The reviving method of the alcohol amine solution as described above, wherein the volume V3 of the regenerating solution and the volume V2 of the to-be-regenerated removing agent satisfy the following relationship:

[0027] V3≥3V2.

[0028] The reviving method of the alcohol amine solution as described above, wherein the regenerating solution is made to flow through the to-be-regenerated removing agent to realize the regenerating treatment of the to-be-regenerated removing agent by the regenerating solution.

[0029] The volume space velocity of the regenerating solution flowing through the to-be-regenerated removing agent is greater than or equal to 4h -1 .

[0030] The reviving method of the alcohol amine solution can remove the heat stable salt in the alcohol amine solution to be revived to form the revived alcohol amine solution rich in ammonium hydrogen phosphate. Since the ammonium hydrogen phosphate has strong selective absorption to H2S, the revived alcohol amine solution formed by the reviving method of the alcohol amine solution still has strong selective absorption to H2S, and the product gas with qualified H2S content can be obtained by using the revived alcohol amine solution in the alcohol amine method purification. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0032] The present application provides a reviving method of alcohol amine solution, comprising the following steps:

[0033] S101: using the hydrogen phosphate removing agent to perform first adsorption treatment on the alcohol amine solution to be revived to obtain a first solution and an adsorption system;

[0034] S102: sequentially using the hydroxyl ion exchange resin and the methyldiethanolamine cation exchange resin to perform second adsorption treatment on the first solution to obtain a second solution;

[0035] S103: performing first mixing treatment on the ammonium sulfate solution and the adsorption system to obtain a third solution and a to-be-regenerated removing agent;

[0036] S104: performing second mixing treatment on the hydrogen ion exchange resin and the third solution to obtain a fourth solution;

[0037] S105: performing third mixing treatment on the second solution and the fourth solution to obtain a reactivated alcohol amine solution.

[0038] Specifically, in S101, the solution to be reactivated is a solution containing heat stable salts, ammonium hydrogen phosphate and N-methyl diethanolamine (MDEA) generated in an alcohol amine purification process; wherein the heat stable salts include at least one of chloride, sulfate, thiosulfate, formate, acetate, glycolate and oxalate, the content of the heat stable salts is 10 ppm-100000 ppm based on the total mass of the solution to be reactivated, and the mass percentage content of MDEA is 30-50%. The hydrogen phosphate removing agent is any material with extremely high selectivity for hydrogen phosphate, and is composed of anions and cations. Since the force between the cations in the hydrogen phosphate removing agent and the hydrogen phosphate is greater than the force between the cations and the anions in the hydrogen phosphate removing agent, the hydrogen phosphate is easy to replace the anions in the hydrogen phosphate removing agent, thereby realizing the adsorption of the hydrogen phosphate in the hydrogen phosphate removing agent. The present application uses the hydrogen phosphate removing agent with extremely high selectivity for hydrogen phosphate to realize the first adsorption treatment on the solution to be reactivated containing heat stable salts and ammonium hydrogen phosphate. In the first adsorption treatment, the anions in the hydrogen phosphate removing agent exchange with the hydrogen phosphate in the solution to be reactivated, thereby adsorbing the hydrogen phosphate in the solution to be reactivated in the hydrogen phosphate removing agent to form a first solution from which the hydrogen phosphate is removed, and an adsorption system in which the hydrogen phosphate is adsorbed.

[0039] In S102, the second adsorption treatment includes: performing adsorption treatment on the first solution formed in S101 by using a hydroxyl ion exchange resin, the anions of the heat stable salts in the first solution exchange with the hydroxyl ions in the hydroxyl ion exchange resin, thereby converting the heat stable salts into inorganic alkali, thereby forming a solution containing inorganic alkali, and then performing adsorption treatment on the solution containing inorganic alkali by using a methyl diethanolamine cation exchange resin, the cations in the inorganic alkali exchange with the methyl diethanolamine cations in the methyl diethanolamine cation exchange resin, thereby converting the inorganic alkali into water and methyl diethanolamine, to obtain a second solution containing water and methyl diethanolamine.

[0040] In S103, the ammonium sulfate solution is mixed with the adsorption system obtained in S101. On one hand, the pH of the ammonium sulfate solution is 4-5, which is relatively weak and cannot easily destroy the crystal structure of the adsorption system. On the other hand, in the environment with a pH of 4-5, the phosphate in the adsorption system is converted into dihydrogen phosphate, and the adsorption system containing dihydrogen phosphate is obtained. The interaction force between dihydrogen phosphate and the cations in the adsorption system is much smaller than the interaction force between sulfate and the cations in the adsorption system. Therefore, the dihydrogen phosphate in the adsorption system is exchanged with the sulfate, and the dihydrogen phosphate in the adsorption system is removed, and a third solution containing dihydrogen phosphate salt is obtained. At the same time, the adsorption system after the first mixing treatment obtains a sulfate-containing regenerable removing agent.

[0041] In S104, the hydrogen ion exchange resin and the third solution containing dihydrogen phosphate salt are subjected to a second mixing treatment. In the second mixing treatment, the cations of the dihydrogen phosphate salt are exchanged with the hydrogen ions in the hydrogen ion exchange resin, and the dihydrogen phosphate salt is converted into phosphoric acid, and a fourth solution containing phosphoric acid is obtained.

[0042] In S105, the second solution obtained in S102 is mixed with the fourth solution obtained in S104. In the third mixing treatment, the phosphoric acid in the fourth solution reacts with the N-methyldiethanolamine (MDEA) in the second solution to obtain ammonium hydrogen phosphate. Therefore, a reviving alcohol amine solution containing ammonium hydrogen phosphate and free of heat stable salts can be obtained.

[0043] It can be understood that the present application does not particularly limit the specific form of the first adsorption treatment, as long as the hydrogen phosphate removing agent can adsorb the hydrogen phosphate in the reviving alcohol amine solution. For example, the hydrogen phosphate removing agent and the reviving alcohol amine solution can be directly mixed to adsorb the hydrogen phosphate in the reviving alcohol amine solution by using the hydrogen phosphate removing agent, so as to realize the first adsorption treatment. Alternatively, the hydrogen phosphate removing agent can be filled in a glass column, and the reviving alcohol amine solution is introduced into the glass column filled with the hydrogen phosphate removing agent, so as to realize the first adsorption treatment.

[0044] The specific form of the second adsorption treatment is not particularly limited in the present application, as long as the heat stable salt in the first solution can be converted into methyldiethanolamine and water. For example, the first solution can be mixed with a hydroxyl ion exchange resin to obtain a solution containing an inorganic base, and then the solution containing the inorganic base is mixed with a methyldiethanolamine cation exchange resin to obtain a second solution containing water and methyldiethanolamine, thereby realizing the second adsorption treatment; the hydroxyl ion exchange resin and the methyldiethanolamine cation exchange resin can be separately filled in a glass column, and the first solution is sequentially flowed through the glass column filled with the hydroxyl ion exchange resin and the glass column filled with the methyldiethanolamine cation exchange resin, thereby realizing the second adsorption treatment; only the hydroxyl ion exchange resin can be filled in a glass column, and the first solution is flowed through the glass column filled with the hydroxyl ion exchange resin to obtain a solution containing an inorganic base, and then the solution containing the inorganic base is mixed with a methyldiethanolamine cation exchange resin, thereby realizing the second adsorption treatment; or only the methyldiethanolamine cation exchange resin can be filled in a glass column, and the first solution is mixed with a hydroxyl ion exchange resin to obtain a solution containing an inorganic base, and then the solution containing the inorganic base is passed into the glass column filled with the methyldiethanolamine cation exchange resin, thereby realizing the second adsorption treatment.

[0045] The specific form of the first mixing treatment and the second mixing treatment is not particularly limited in the present application, as long as the first mixing treatment and the second mixing treatment can be realized. Specifically, the form of the first mixing treatment and the second mixing treatment can refer to the first mixing treatment.

[0046] The hydroxyl ion exchange resin, the methyldiethanolamine cation exchange resin and the hydrogen ion exchange resin are not particularly limited in the present application, and can be selected from the commonly used hydroxyl ion exchange resin, methyldiethanolamine cation exchange resin and hydrogen ion exchange resin in the art.

[0047] The ammonium sulfate solution is not particularly limited in the present application, and can be selected from the commonly used ammonium sulfate solution in the art, for example, an aqueous ammonium sulfate solution can be selected.

[0048] The order of S102 and S103 is not limited in the present application, and in the actual application process, S102 can be performed first, S103 can be performed first, or S102 and S103 can be performed simultaneously.

[0049] The alcohol amine solution reviving method of the present application can make the removal rate of the heat stable salt greater than 96%, and the retention rate of the ammonium hydrogen phosphate greater than 98.5% (the removal rate of the ammonium hydrogen phosphate is less than or equal to 1.5%). Compared with the existing alcohol amine solution reviving method (the removal rate of the heat stable salt is greater than 94%, and the retention rate of the ammonium hydrogen phosphate is less than 2%), the alcohol amine solution reviving method of the present application has excellent removal rate of the heat stable salt and excellent retention rate of the ammonium hydrogen phosphate. Therefore, the revived alcohol amine solution obtained by the alcohol amine solution reviving method of the present application has excellent H2S selective absorption property, which is beneficial to obtain product gas with qualified H2S content; and the composite alcohol amine solution has low corrosion, which is beneficial to avoid corrosion of the alcohol amine purification device, so that the alcohol amine purification device can be stably operated for a long time.

[0050] It is worth mentioning that the alcohol amine solution reviving method of the present application can recycle and reuse the alcohol amine solution, effectively reduce the production cost and environmental protection pressure of the factory, and has excellent economic and social benefits.

[0051] In some embodiments of the present application, the hydrogen phosphate ion removing agent is [Ca (2～3) Sc(OH) (6～8) ]OH.

[0052] [Ca (2～3) Sc(OH) (6～8) ]OH. [Ca (2～3) Sc(OH) (6～8) ]OH has extremely high selective absorption property for hydrogen phosphate ions, and the ratio of the selective absorption rate of [Ca (2～3) Sc(OH) (6～8) ]OH for hydrogen phosphate ions to the selective absorption rate of [Ca (2～3) Sc(OH) (6～8) ]OH for heat stable salt anions is greater than 6000; and the adsorption capacity of [Ca (2～3) Sc(OH) (6～8) ]OH for hydrogen phosphate ions (the adsorption mass of unit mass of [Ca (2～3) Sc(OH) (6～8) ]OH) is greater than 169 mg / g. Therefore, the selection of [Ca (2～3) Sc(OH) (6～8) ]OH as the hydrogen phosphate ion removing agent can not only greatly realize the selective adsorption of hydrogen phosphate ions in the alcohol amine solution to be revived, but also can adsorb a large amount of hydrogen phosphate ions, which is convenient for industrial application.

[0053] In some embodiments of the present application, in order to achieve sufficient adsorption of the hydrogen phosphate removing agent to the hydrogen phosphate in the alcohol amine solution to be revived, the mass m0 of the alcohol amine solution to be revived, the mass percentage p0 of the hydrogen phosphate in the alcohol amine solution to be revived, the mass m1 of the hydrogen phosphate removing agent, and the adsorption mass m2 per unit mass of the hydrogen phosphate removing agent can be specifically selected. The mass m0 of the alcohol amine solution to be revived, the mass percentage p0 of the hydrogen phosphate in the alcohol amine solution to be revived, the mass m1 of the hydrogen phosphate removing agent, and the adsorption mass m2 per unit mass of the hydrogen phosphate removing agent satisfy the following relationship:

[0054] m0*p0≤m1*m2*90%.

[0055] In some embodiments of the present application, in order to enable sufficient contact between the alcohol amine solution to be revived and the hydrogen phosphate removing agent, and enable the hydrogen phosphate removing agent to adsorb as much hydrogen phosphate in the alcohol amine solution to be revived as possible, the alcohol amine solution to be revived can be made to flow through the hydrogen phosphate removing agent, thereby achieving a first treatment of the alcohol amine solution to be revived by the hydrogen phosphate removing agent.

[0056] The volume space velocity of the alcohol amine solution to be revived flowing through the hydrogen phosphate removing agent is less than or equal to 5h -1 .

[0057] In specific embodiments, the volume space velocity of the alcohol amine solution to be revived flowing through the hydrogen phosphate removing agent is 4h -1 .

[0058] In the present application, in order to obtain as much dihydrogen phosphate as possible from the adsorption system, and further obtain as much hydrogen phosphate as possible, the volume V1 of the ammonium sulfate solution, the volume molar concentration C1 of the ammonium sulfate solution, the volume V0 of the alcohol amine solution to be revived, and the volume molar concentration C0 of the hydrogen phosphate in the alcohol amine solution to be revived can be specifically selected.

[0059] For example, the volume V1 of the ammonium sulfate solution, the volume molar concentration C1 of the ammonium sulfate solution, the volume V0 of the alcohol amine solution to be revived, and the volume molar concentration C0 of the hydrogen phosphate in the alcohol amine solution to be revived satisfy the following relationship:

[0060] V1*C1=1.5V0*C0.

[0061] In some embodiments of the present application, in order to enable the ammonium sulfate solution to be in contact with the adsorption system, obtain as much dihydrogen phosphate as possible from the adsorption system, and further obtain as much hydrogen phosphate as possible, the ammonium sulfate solution can be made to flow through the adsorption system, thereby achieving a first mixing treatment of the ammonium sulfate solution and the adsorption system.

[0062] Further, the volume space velocity of the ammonium sulfate solution flowing through the adsorption system is less than or equal to 4h -1 .

[0063] In a specific embodiment, the volume hourly space velocity of the ammonium sulfate solution flowing through the adsorption system is 3h -1 .

[0064] In some embodiments of the present application, the ammonium sulfate solution has a volume molar concentration of 1.2-2.3 mol / L.

[0065] In the present application, when the molar concentration of the ammonium sulfate solution is within the above range, the ammonium sulfate solution has a more suitable pH, and the dihydrogen phosphate can be obtained from the adsorption system without destroying the crystal structure of the adsorption system, and further the phosphate ion can be obtained; and when the molar concentration of the ammonium sulfate solution is within the above range, the ammonium sulfate solution has a proper volume, so that the adsorption system can be completely soaked, which is beneficial to completely removing the hydrogen phosphate in the adsorption system. Further, the molar concentration of the ammonium sulfate solution is 1.9-2.0 mol / L.

[0066] In some embodiments of the present application, the reviving method of the alcohol amine solution further comprises: regenerating the to-be-regenerated removal agent by using a regeneration liquid to obtain a regenerated removal agent;

[0067] The regeneration liquid is selected from a sodium hydroxide aqueous solution and / or a potassium hydroxide aqueous solution.

[0068] In the present application, the ammonium sulfate solution and the adsorption system are subjected to the first mixing treatment to obtain the to-be-regenerated removal agent containing sulfate, and the to-be-regenerated removal agent containing sulfate is subjected to the regeneration treatment by using the sodium hydroxide aqueous solution and / or the potassium hydroxide aqueous solution, so that the hydroxyl ions in the sodium hydroxide aqueous solution and / or the potassium hydroxide aqueous solution are exchanged with the sulfate in the to-be-regenerated removal agent to form the regenerated removal agent.

[0069] The present application does not limit the specific form of the regeneration treatment, as long as the hydroxyl ions in the sodium hydroxide aqueous solution and / or the potassium hydroxide aqueous solution can be exchanged with the sulfate in the to-be-regenerated removal agent to form the regenerated removal agent. For example, the to-be-regenerated removal agent can be statically soaked in the sodium hydroxide aqueous solution and / or the potassium hydroxide aqueous solution to realize the regeneration treatment; or the to-be-regenerated removal agent can be placed in a glass column, and the regeneration liquid flows through the glass column filled with the to-be-regenerated removal agent to realize the regeneration treatment.

[0070] The present application does not limit the flow rate of the regeneration liquid through the glass column filled with the to-be-regenerated removal agent, and in some embodiments, when the flow rate of the regeneration liquid through the glass beads filled with the to-be-regenerated removal agent is large, it is beneficial to make the liquid layer at the interface between the to-be-regenerated removal agent and the regeneration liquid have a higher hydroxyl ion concentration and a lower sulfate ion concentration, beneficial to the diffusion of the hydroxyl ion in the regeneration liquid to the inside of the to-be-regenerated removal agent, and the sulfate ion in the to-be-regenerated removal agent into the regeneration liquid, achieving sufficient regeneration of the to-be-regenerated removal agent, and obtaining a regenerated removal agent with excellent quality.

[0071] Further, in some embodiments of the present application, the regeneration liquid is made to flow through the to-be-regenerated removal agent to achieve the regeneration treatment of the to-be-regenerated removal agent by the regeneration liquid;

[0072] The volume space velocity of the regeneration liquid flowing through the to-be-regenerated removal agent is greater than or equal to 4h -1 .

[0073] In a specific embodiment, the volume V3 of the regeneration liquid and the volume V2 of the to-be-regenerated removal agent satisfy V3=4V2, and the volume space velocity of the regeneration liquid flowing through the to-be-regenerated removal agent is 6h -1 .

[0074] In the present application, the to-be-regenerated removal agent is regenerated by the regeneration liquid, which can obtain a regenerated removal agent with excellent quality, realize the regeneration and reuse of the hydrogen phosphate removal agent, and has excellent economic value.

[0075] In some embodiments of the present application, in order to make the regeneration liquid fully infiltrate the to-be-regenerated removal agent, achieve complete removal of sulfate ions in the to-be-regenerated removal agent, and obtain a regenerated removal agent with excellent quality, the concentration of hydroxyl ions in the regeneration liquid is 1.3-1.5 mol / L.

[0076] In some embodiments of the present application, in order to remove as much phosphate in the to-be-regenerated removal agent as possible and obtain a regenerated removal agent with excellent quality, the volume V3 of the regeneration liquid and the volume V2 of the to-be-regenerated removal agent can be specifically selected. For example, the volume V3 of the regeneration liquid and the volume V2 of the to-be-regenerated removal agent satisfy the following relationship:

[0077] V3≥3V2.

[0078] In the following, the technical solutions of the present application will be further described in combination with specific examples.

[0079] Example 1

[0080] The reviving method of the alcohol amine solution of the present embodiment includes the following steps:

[0081] 1) To-be-regenerated alcohol amine solution

[0082] The mass percentage of the heat stable salt is 1.4%, the mass percentage of N-methyldiethanolamine is 45%, and the mass percentage of hydrogen phosphate is 4%, and the volume concentration of hydrogen phosphate is 0.43 mol / L, based on the total mass of the alcohol amine solution to be reactivated;

[0083] The mass ratio of sulfate ions, thiosulfate, chloride ions, formate, acetate, glycolate, and oxalate in the alcohol amine solution to be reactivated is 1:1:1:1:1:1:1.

[0084] 2) treatment column

[0085] 1st column: 100 g of hydrogen phosphate remover [Ca3Sc(OH)8]OH is packed in a glass column with an inner diameter of 25 mm, and the adsorption capacity of [Ca3Sc(OH)8]OH is 174 mg / g;

[0086] 2nd column: 100 g of hydroxide ion exchange resin is packed in a glass column with an inner diameter of 25 mm;

[0087] 3rd column: 100 g of methyldiethanolamine ion exchange resin is packed in a glass column with an inner diameter of 25 mm;

[0088] 4th column: 100 g of hydrogen ion exchange resin is packed in a glass column with an inner diameter of 25 mm.

[0089] 3) first reactivation treatment

[0090] The alcohol amine solution to be reactivated is passed through the 1st column for first adsorption treatment, and nitrogen is used to discharge the solution retained in the 1st column from top to bottom to obtain a first solution, and the hydrogen phosphate remover in the 1st column is converted into an adsorption system;

[0091] The first solution is passed through the 2nd column and the 3rd column in sequence for second adsorption treatment, and nitrogen is used to discharge the solution retained in the 2nd column and the 3rd column from top to bottom in sequence to obtain a second solution;

[0092] The ammonium sulfate solution is passed through the 1st column filled with the adsorption system for first mixing treatment, and nitrogen is used to discharge the solution retained in the 1st column from top to bottom to obtain a third solution, and the adsorption system in the 1st column is converted into a reactivated remover;

[0093] The third solution is passed through the 4th column for second mixing treatment, and nitrogen is used to discharge the solution retained in the 4th column from top to bottom to obtain a fourth solution;

[0094] The fourth solution and the second solution are subjected to third mixing treatment to obtain a first reactivated alcohol amine solution;

[0095] The mass of the alcohol amine solution to be revived is 380 g, the volume of the alcohol amine solution to be revived is 365 mL, the volume space velocity of the alcohol amine solution to be revived flowing through the No. 1 column is 5 h -1 , the volume space velocity of the first solution flowing through the No. 2 column and the No. 3 column is 5 h -1 , the volume of the removal agent to be regenerated is 125 mL;

[0096] The ammonium sulfate solution is an aqueous ammonium sulfate solution, the volume molar concentration of the aqueous ammonium sulfate solution is 1.2 mol / L, the volume of the aqueous ammonium sulfate solution is 197 mL, and the volume space velocity of the aqueous ammonium sulfate solution flowing through the No. 1 column is 4 h -1 , the volume space velocity of the third solution flowing through the No. 4 column is 4 h -1 .

[0097] 4) Regeneration treatment of the removal agent to be regenerated

[0098] The regeneration liquid is flowed through the No. 1 column, then distilled water is flowed through the No. 1 column, and finally the solution remaining in the No. 1 column is discharged from top to bottom by using nitrogen, so that the removal agent to be regenerated in the No. 1 column is regenerated to form a regenerated removal agent;

[0099] The regeneration liquid is an aqueous sodium hydroxide solution, in the regeneration liquid, the molar concentration of hydroxide is 1.3 mol / L, the volume of the regeneration liquid is 500 mL, and the volume space velocity of the regeneration liquid flowing through the No. 1 column is 5 h -1 ;

[0100] The volume of the distilled water is 120 mL, and the volume space velocity of the distilled water flowing through the No. 1 column is 4 h -1 .

[0101] 5) Regeneration treatment of the No. 2 column, the No. 3 column and the No. 4 column

[0102] 400 mL of the aqueous sodium hydroxide solution with a mass fraction of 4% is flowed through the No. 2 column, and then the solution remaining in the No. 2 column is discharged from top to bottom by using nitrogen, so that the resin in the No. 2 column is regenerated;

[0103] 400 mL of the aqueous methyl glycol amine chloride solution with a mass fraction of 3% is flowed through the No. 3 column, and then the solution remaining in the No. 3 column is discharged from top to bottom by using nitrogen, so that the resin in the No. 3 column is regenerated;

[0104] 300 mL of the aqueous hydrochloric acid solution with a mass fraction of 3% is flowed through the No. 4 column, and then the solution remaining in the No. 4 column is discharged from top to bottom by using nitrogen, so that the resin in the No. 4 column is regenerated.

[0105] 6) Second revival treatment

[0106] The step 3) is repeated to obtain a second alcohol amine solution to be revived.

[0107] 7) The mass and volume of the first and second revived alcohol amine solutions are measured, and the concentrations of ammonium hydrogen phosphate and various heat stable salt anions in the first and second revived alcohol amine solutions are determined, and the removal rates of ammonium hydrogen phosphate and various heat stable salt anions in the first and second revived alcohol amine solutions are calculated, and the results are shown in Table 1.

[0108] Table 1

[0109]

[0110] As can be seen from Table 1, the removal rate of the heat stable salt in the alcohol amine solution revival method of the present application is >96%, and the removal rate of ammonium hydrogen phosphate is <2.0%, which shows that the alcohol amine solution revival method of the present application can remove the heat stable salt while retaining the ammonium hydrogen phosphate in the alcohol amine solution to be revived;

[0111] And since the removal rate of ammonium hydrogen phosphate in the first and second revived alcohol amine solutions is both less than 2.0%, it shows that the alcohol amine solution revival method of the present application can also regenerate and utilize the ammonium hydrogen phosphate removal agent repeatedly.

[0112] Example 2

[0113] The alcohol amine solution revival method of the present example is basically the same as that of Example 1, except that:

[0114] The ammonium hydrogen phosphate removal agent in step 2) is ZnAl layered double hydroxide.

[0115] Example 3

[0116] The alcohol amine solution revival method of the present example is basically the same as that of Example 1, except that:

[0117] In step 3), the volume space velocity of the alcohol amine solution to be revived flowing through No. 1 column is 6h -1 , and the volume space velocity of the first solution flowing through No. 2 column and No. 3 column is 5h -1 .

[0118] The volume space velocity of the ammonium sulfate aqueous solution flowing through No. 1 column is 5h -1 .

[0119] In step 4), the volume space velocity of the regeneration liquid flowing through No. 1 column is 3h -1 .

[0120] Comparative Example

[0121] The alcohol amine solution to be revived in Example 1 is revived by ion exchange method, electrodialysis method and reduced pressure distillation method respectively to obtain a revived alcohol amine solution;

[0122] Specifically, ion exchange method: the alcohol amine solution to be revived flows from top to bottom through the anion exchange resin, and the outflowing solution is the revived alcohol amine solution;

[0123] The volume of the anion exchange resin is 100 mL, and the volume of the alcohol amine solution to be revived is 150 mL.

[0124] The volume space velocity of the alcohol amine solution to be revived flowing through the anion exchange resin is 4h-1. -1 .

[0125] Electrodialysis method: the anion and cation exchange membranes, the concentrated and dilute water partitions, the positive and negative electrodes, the electrode frame, and the water guide plate are pressed tightly by a clamping device to form an electrodialysis device. 25 g of sodium hydroxide is added to 500 g of the alcohol amine solution to be revived, and the mixed solution is allowed to react for 10 minutes. The sodium hydroxide reacts with the heat stable salt to generate a heat stable sodium salt and MDEA. The reacted solution is poured into the electrodialysis device, and a direct current is passed through. Since the heat stable sodium salt is a strong electrolyte, it ionizes to generate positively charged sodium ions and negatively charged anions. Under the action of the direct current electric field, the sodium ions pass through the cation exchange membrane, and the anions pass through the anion exchange membrane to enter the concentrated brine pool. MDEA and water are weak electrolytes and almost do not ionize, and are left in the dilute water pool. The solution left in the dilute water pool is the revived alcohol amine solution.

[0126] Vacuum distillation method: 200 g of the alcohol amine solution to be revived is added to a distillation flask, the system is vacuumed to a pressure of 90.3 kPa, and the solution is heated to 150℃. After 20 minutes of distillation, the solution in the receiving flask is the revived alcohol amine solution.

[0127] The concentrations of the heat stable salt and the dihydrogen phosphate amine in the revived alcohol amine obtained by the ion exchange method, the electrodialysis method, and the vacuum distillation method are measured, and the removal rates of the heat stable salt and the dihydrogen phosphate amine in the revived alcohol amine obtained by the ion exchange method, the electrodialysis method, and the vacuum distillation method are calculated, respectively. The results are shown in Table 2.

[0128] The concentration of the heat stable salt in the second revived alcohol amine solution of Examples 1-3 is directly measured by ion chromatography SY / T 7001, and the removal rate of the heat stable salt in the second revived alcohol amine solution is calculated according to the following formula. The results are shown in Table 2.

[0129] The removal rate of the heat stable salt = (total mass fraction of heat stable salt anions before revival - total mass fraction of heat stable salt anions after revival) ÷ total mass fraction of heat stable salt anions before revival × 100%.

[0130] Table 2

[0131]

[0132] As can be seen from Table 2, the treatment of the alcohol amine solution to be revived by the alcohol amine solution revival method of the present application can not only remove most of the heat stable salts in the alcohol amine solution to be revived, but also hardly lose the ammonium hydrogen phosphate in the alcohol amine solution to be revived.

[0133] Especially, the use of the hydrogen phosphate removing agent [Ca (2～3) Sc(OH) (6～8) ]OH, and the control of the volume space velocity of the alcohol amine solution to be revived flowing through the hydrogen phosphate removing agent, the volume space velocity of the ammonium sulfate solution flowing through the adsorption system, and the volume space velocity of the regeneration liquid flowing through the removing agent to be regenerated, can better remove the heat stable salts in the alcohol amine solution to be revived, and hardly lose the ammonium hydrogen phosphate in the alcohol amine solution to be revived. Compared with the ion exchange method, the electrodialysis method and the reduced pressure distillation method (the removal rate of the heat stable salts is greater than 94%, the removal rate of the ammonium hydrogen phosphate is greater than 98%, and the retention rate of the ammonium hydrogen phosphate is less than 2%), the alcohol amine solution revival method of the present application can better retain the ammonium hydrogen phosphate in the alcohol amine solution to be revived while removing more heat stable salts in the alcohol amine solution to be revived (the removal rate of the heat stable salts is greater than 96%, the removal rate of the ammonium hydrogen phosphate is 1.5%, and the retention rate of the ammonium hydrogen phosphate is 98.5%).

[0134] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for reviving an alcohol amine solution, characterized by, The method comprises the following steps: a first adsorption treatment is performed on the alcohol amine solution to be regenerated by using a hydrogen phosphate removing agent, to obtain a first solution and an adsorption system; a second adsorption treatment is performed on the first solution by using a hydroxyl ion exchange resin and a methyldiethanolamine cation exchange resin in sequence, to obtain a second solution; a first mixing treatment is performed on the adsorption system by using an ammonium sulfate solution, to obtain a third solution and a removing agent to be regenerated; a second mixing treatment is performed on the third solution by using a hydrogen ion exchange resin, to obtain a fourth solution; a third mixing treatment is performed on the second solution and the fourth solution, to obtain a regenerated alcohol amine solution.

2. The method of reviving an alcohol amine solution of claim 1, wherein, The hydrogen phosphate removing agent is [Ca (2～3) Sc(OH) (6～8) ]OH.

3. The method of reviving an alcohol amine solution according to any one of claims 1-2, characterized in that, The mass m0 of the alcohol amine solution to be regenerated, the mass percentage content p0 of hydrogen phosphate in the alcohol amine solution to be regenerated, the mass m1 of the hydrogen phosphate removing agent, and the adsorption mass m2 per unit mass of the hydrogen phosphate removing agent satisfy the following relationship: m0*p0≤m1*m2*90%.

4. The method of reviving an alcohol amine solution according to any one of claims 1 to 3, characterized in that, The alcohol amine solution to be regenerated flows through the hydrogen phosphate removing agent, to realize the first adsorption treatment of the hydrogen phosphate removing agent on the alcohol amine solution to be regenerated; The volume hourly space velocity of the to-be-resuscitated alcohol amine solution flowing through the hydrogen phosphate remover is less than or equal to 5 h -1 .

5. The method of reviving an alcohol amine solution according to any one of claims 1 to 4, characterized in that, The volume V1 of the ammonium sulfate solution, the volume molar concentration C1 of the ammonium sulfate solution, the volume V0 of the alcohol amine solution to be regenerated, and the volume molar concentration C0 of hydrogen phosphate in the alcohol amine solution to be regenerated satisfy the following relationship: V1*C1=1.5V0*C0; and / or, The ammonium sulfate solution flows through the adsorption system, to realize the first mixing treatment of the ammonium sulfate solution and the adsorption system; The volume hourly space velocity of the ammonium sulfate solution through the adsorption system is less than or equal to 4 h -1 .

6. The method of reviving an alcohol amine solution according to any one of claims 1 to 5, characterized in that, The volume molar concentration of the ammonium sulfate solution is 1.2-2.3 mol / L.

7. The method of reviving an alcohol amine solution according to any one of claims 1 to 6, characterized in that, The method for regenerating the alcohol amine solution further comprises: performing a regeneration treatment on the removing agent to be regenerated by using a regeneration liquid, to obtain a regenerated removing agent; The regeneration liquid is selected from a sodium hydroxide aqueous solution and / or a potassium hydroxide aqueous solution.

8. The method of reviving an alcohol amine solution of claim 7, wherein, The concentration of hydroxyl in the regeneration liquid is 1.3-1.5 mol / L.

9. The method of reviving an alcohol amine solution of claim 8, wherein, The volume V3 of the regeneration liquid and the volume V2 of the removing agent to be regenerated satisfy the following relationship: V3≥3V2.

10. The method of reviving an alcohol amine solution according to any one of claims 7-9, characterized in that, The regeneration liquid flows through the removing agent to be regenerated, to realize the regeneration treatment of the regeneration liquid on the removing agent to be regenerated. The volume space velocity of the regeneration stream through the volume of the desorbent to be regenerated is greater than or equal to 4 h -1 .

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