Activated potassium base solution for removing carbon dioxide from oxygen-containing gas mixture, application thereof and method for removing carbon dioxide

Abstract

The present application relates to the field of gas purification, discloses a kind of activated potassium base solution for removing carbon dioxide in oxygen-containing gas and application and carbon dioxide removal method.Activated potassium base solution for removing carbon dioxide in oxygen-containing gas includes potassium carbonate, amino acid activator, ionic liquid and water;Wherein, the anion in the ionic liquid is selected from at least one of acetate ion, lactate ion, amino acid salt ion.The activated potassium base solution described in the present application has high decarburization efficiency, is resistant to oxidative degradation, resistant to thermal degradation, has low toxicity, has little corrosivity to equipment, and is not prone to cause decarburization system blockage.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of gas purification, and particularly relates to an activated potassium base solution for removing carbon dioxide from oxygen-containing gas and application and a method for removing carbon dioxide. BACKGROUND

[0002] Ethylene oxide is an important chemical. The preparation method on an industrial scale is usually to obtain it by directly oxidizing ethylene in the presence of a silver catalyst, and in the process, a mixed gas of hydrocarbons, carbon dioxide and oxygen, referred to as a circulating gas (i.e. an oxygen-containing mixed gas), is produced. Before the circulating gas is returned to the ethylene reactor for recycling, the carbon dioxide therein needs to be removed to below an index (0.5 vol. %).

[0003] After comparing various decarbonization methods such as the amine method and the physical absorption method, the currently widely used process is the hot potassium base decarbonization technology. The hot potassium base process has the lowest hydrocarbon loss. This technology was developed by the US Bureau of Mines for coal-to-oil technology in the 1950s, and later different countries developed their own technologies, such as the G-V method, the Benfield method and the Catacarb method. Although the arsenic trioxide activator used in the G-V method has a high absorption rate, it is toxic. The activators used in the Benfield and Catacarb methods are alkyl alcohol amines. Since the 1970s, domestic research on the hot potassium base technology has been carried out, mainly using amines or inorganic salts as activators, and it has been successfully applied in many chemical fertilizer plants. Therefore, the activators used in the hot potassium base process include alcohol amines, steric amines and metal salts. However, since there is oxygen and other oxidizing gases in the ethylene epoxidation process, the above-mentioned methods for removing carbon dioxide from the circulating gas of the ethylene epoxidation process have problems such as many side reactions, amine degradation and high solution toxicity. In addition, the existing hot potassium base process also has the problem of corrosion of equipment and pipelines.

[0004] CN102675248A discloses a method for removing carbon dioxide from the circulating gas of ethylene oxide ethylene glycol synthesis, and proposes a method and a solvent for removing the circulating gas, wherein the activator of the decarbonization solution is an inorganic activator, mainly a salt of vanadium, boron, selenium, antimony, tellurium and other metals. However, the inorganic activator is a heavy metal salt, which is highly toxic.

[0005] CN103118760B discloses a method for removing carbon dioxide from a circulating gas system, and proposes a decarbonization solution which does not use potassium carbonate but uses one or more aqueous amine solutions, such as triethylene diamine, piperazine and methyldiethanolamine. However, this patent does not address the problem of amine degradation. However, it is known to those skilled in the art that under oxygen-containing conditions, amine solutions generally undergo chemical and thermal degradation, and the degradation products have a negative impact on the normal and stable operation of the decarbonization system, affecting the decarbonization effect. SUMMARY

[0006] The present application aims to overcome the problems of the prior art, such as many side reactions during the removal of carbon dioxide from oxygen-containing mixed gas, easy degradation of amine in the decarburization solution, high toxicity, high corrosivity to equipment, high cost, and easy plugging of the decarburization system, and provides an activated potassium base solution for removing carbon dioxide from oxygen-containing gas, and application and a method for removing carbon dioxide, which has the advantages of high decarburization efficiency, resistance to oxidative degradation, resistance to thermal degradation, low toxicity, low corrosivity to equipment, and no easy plugging of the decarburization system.

[0007] To achieve the above-mentioned purpose, the present application provides, in a first aspect, an activated potassium base solution for removing carbon dioxide from oxygen-containing gas, wherein the solution comprises potassium carbonate, an amino acid activator, an ionic liquid, and water.

[0008] The anion in the ionic liquid is selected from at least one of acetate ions, lactate ions, and amino acid salt ions.

[0009] The present application provides, in a second aspect, the use of the above-mentioned activated potassium base solution in the removal of carbon dioxide from oxygen-containing mixed gas.

[0010] The present application provides, in a third aspect, a method for removing carbon dioxide from oxygen-containing mixed gas, which comprises: contacting an activated potassium base solution as lean liquid with oxygen-containing mixed gas in countercurrent to obtain rich liquid and purified gas; wherein the activated potassium base solution is the activated potassium base solution provided by the present application.

[0011] The present application has the following advantages:

[0012] (1) Compared with other decarburization solutions in the prior art, the activated potassium base solution of the present application has the advantages of high carbon dioxide absorption efficiency, stable properties, low toxicity, low corrosivity to equipment, and no easy plugging of the decarburization system, and does not contain amine solution, is resistant to oxidative degradation, and does not undergo chemical degradation during contact with oxygen-containing mixed gas, and can be used for decarburization of oxygen-containing mixed gas, and in particular can absorb and remove carbon dioxide from oxygen-containing mixed gas containing hydrocarbons, carbon dioxide, and other components;

[0013] (2) The amino acid activator of the present application can further improve the carbon dioxide absorption performance of the activated potassium base solution, and can improve the oxygen resistance of the activated potassium base solution;

[0014] (3) The ionic liquid used in the present application can further reduce the corrosion of the activated potassium base solution to the decarburization system, and has low toxicity compared with the existing corrosion inhibitors used in hot potassium base solution; in addition, the ionic liquid of the present application has the advantages of not easily causing plugging of the decarburization system, and can further improve the oxygen resistance of the activated potassium base solution.

[0015] (4) The potassium carbonate, amino acid activator and ionic liquid in the present application have a synergistic effect, and the prepared solution is a homogeneous system solution, the salts contained in the solution do not precipitate, and the solution does not cause the blockage of the decarburization system. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 A schematic diagram of a decarburization device for oxygen-containing mixed gas used in the present application.

[0017] BRIEF DESCRIPTION OF DRAWINGS

[0018] 1 - absorption tower 3 - lean-rich liquid heat exchanger 5 - regeneration tower 7 - second water cooler

[0019] 2 - first water cooler 4 - lean liquid pump 6 - boiling kettle DETAILED DESCRIPTION

[0020] The endpoints of the ranges and any values claimed herein are not to be understood as being limited to the exact values recited as implicitly disclosed by the above description. Ranges can be expressed as from one value and / or to another value. When such a range is expressed, the endpoints are included in the range. When, in this specification, a range or parameter is given, an upper value and a lower value are provided. Unless otherwise stated, the range includes the endpoints. When a parameter is said to be "about" a value, the parameter is at least as close as practical measurements reasonably can determine.

[0021] The first aspect of the present application provides an activated potassium base solution for removing carbon dioxide from an oxygen-containing gas, the solution comprising potassium carbonate, an amino acid activator, an ionic liquid and water.

[0022] The anion in the ionic liquid is selected from at least one of acetate ion, lactate ion and amino acid salt ion.

[0023] In some embodiments of the present application, the content of potassium carbonate in the solution is 10-30 wt%, the content of the amino acid activator is 2-10 wt%, the content of the ionic liquid is 0.02-0.45 wt%, and the content of water is 59.55-87.98 wt%, based on the total amount of the solution.

[0024] In the present application, the sum of the contents of potassium carbonate, the amino acid activator, the ionic liquid and water in the solution is 100 wt%.

[0025] In the present application, the content of potassium carbonate is 10-30 wt%, and when the content of potassium carbonate is controlled in this range, the activated potassium base solution has high absorption efficiency for carbon dioxide and good decarburization effect. When the content of potassium carbonate is less than 10 wt%, the absorption efficiency of the activated potassium base solution is low. When the content of potassium carbonate is higher than 30 wt%, the activated potassium base solution is prone to crystallization.

[0026] In the present application, the content of the amino acid activator is 2-10 wt%, when the content of the amino acid activator is within the range, the absorption efficiency of the activated potassium base solution to carbon dioxide is high, the decarbonization effect is good, and the oxidation resistance is good. When the content of the amino acid activator is less than 2 wt%, the absorption efficiency of the activated potassium base solution is low, and the activation effect of the amino acid activator is not obvious; when the content of the amino acid activator is higher than 10 wt%, the cost is higher.

[0027] In the present application, the content of the ionic liquid is 0.02-0.45 wt%. When the content of the ionic liquid is within the above range, the corrosion inhibition effect of the activated potassium base solution is the best. When the content of the ionic liquid is less than 0.02 wt%, the corrosion inhibition effect of the activated potassium base solution is poor; when the content of the ionic liquid is higher than 0.45 wt%, the corrosion inhibition effect is not obvious, and the cost is higher.

[0028] In some embodiments of the present application, based on the total amount of the solution, the content of potassium carbonate is 10-30 wt%, the content of the amino acid activator is 3-6 wt%, the content of the ionic liquid is 0.05-0.2 wt%, and the content of water is 63.8-86.45 wt%.

[0029] In some embodiments of the present application, the amino acid activator is an amino acid. Preferably, the chemical structure of the amino acid does not contain a benzene ring. In order to further improve the absorption efficiency of the activated potassium base solution to carbon dioxide, the amino acid is preferably at least one of glycine, aminohexanoic acid, glutamic acid, alanine, lysine, arginine, and proline.

[0030] The inventors found that when the above-mentioned amino acid is used as the amino acid activator, there is a synergistic effect between the potassium carbonate and the ionic liquid, the absorption efficiency of the prepared activated potassium base solution to carbon dioxide is high, the oxidation resistance of the activated potassium base solution can be significantly improved, and salt precipitation and precipitation are not generated, which is not easy to cause the blockage of the decarbonization system.

[0031] In the present application, the "salt" refers to a salt containing potassium ions.

[0032] In the present application, the ionic liquid can be completely dissolved in the potassium carbonate solution to form a homogeneous solution.

[0033] In the present application, the addition of the ionic liquid can reduce the corrosion of the activated potassium base solution to the decarbonization system. Preferably, the ionic liquid contains a nitrogen-containing group. Further preferably, the ionic liquid is a hydrophilic ionic liquid.

[0034] In some embodiments of the present application, in order to further reduce the corrosion of the activated potassium base solution to the carbon steel equipment, the ionic liquid is a methylimidazole ionic liquid and / or a quaternary ammonium ionic liquid.

[0035] In some embodiments of the present application, the anion in the ionic liquid is selected from at least one of acetate ion, lactate ion, and amino acid salt ion.

[0036] In some embodiments of the present application, the ionic liquid is selected from at least one of 2-hydroxy-N,N,N-trimethylethanaminium glycinate, 2-hydroxy-N,N,N-trimethylethanaminium alaninate, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium lactate, and 1-butyl-3-methylimidazolium acetate. The inventors have found in the research that when the ionic liquid is of the above type, there is a synergistic effect with potassium carbonate and amino acid, and the prepared activated potassium base solution has no salt precipitation or precipitation, which is not easy to cause corrosion to the decarbonization system.

[0037] In some embodiments of the present application, the pH of the activated potassium base solution is 11-13.

[0038] The second aspect of the present application provides the use of the above-mentioned activated potassium base solution in removing carbon dioxide from oxygen-containing mixed gas.

[0039] In the present application, the oxygen-containing mixed gas refers to an oxygen-containing mixed gas generated in a chemical reaction process. In addition to oxygen and carbon dioxide, the mixed gas also contains olefin gas, alkane gas, inert gas, etc.

[0040] In some embodiments of the present application, in the use, the pressure of the oxygen-containing mixed gas is 2-4 MPa, and the temperature is 50-80℃; the volume content of oxygen is 3-8% and the volume content of carbon dioxide is 2-6% based on the volume of the oxygen-containing mixed gas.

[0041] The third aspect of the present application provides a method for removing carbon dioxide from oxygen-containing mixed gas, which comprises: countercurrently contacting an activated potassium base solution with oxygen-containing mixed gas to capture carbon dioxide, to obtain a rich solution and a purified gas; wherein the activated potassium base solution is the activated potassium base solution provided by the present application.

[0042] In some embodiments of the present application, in the use, the pressure of the oxygen-containing mixed gas is 2-4 MPa, and the temperature is 50-80℃; the volume content of oxygen is 3-8% and the volume content of carbon dioxide is 2-6% based on the volume of the oxygen-containing mixed gas.

[0043] In the present application, the conditions of countercurrent contact are not particularly limited and can be the conventional conditions of countercurrent contact in the art.

[0044] In some embodiments of the present application, the method further comprises: regenerating the rich solution into a lean solution; and returning the obtained lean solution to the carbon dioxide capture.

[0045] In some embodiments of the present invention, the regeneration conditions are: temperature 110-130℃, pressure 0.02-0.06MPa.

[0046] In some embodiments of the present invention, the rich liquid undergoes heat exchange before regeneration.

[0047] In some embodiments of the present invention, the removal of carbon dioxide from the oxygen-containing gas mixture by the activated potassium alkali solution is carried out in a decarbonization device, such as... Figure 1 As shown, the decarbonization device includes an absorption tower 1, a first water cooler 2, a lean-rich solution heat exchanger 3, a lean solution pump 4, a regeneration tower 5, a boiling vessel 6, and a second water cooler 7. An activated potassium hydroxide solution is added to the absorption tower 1. The oxygen-containing mixed gas enters the lower part of the absorption tower 1 and comes into countercurrent contact with the activated potassium hydroxide solution entering from the upper and middle parts of the absorption tower 1 to capture carbon dioxide, obtaining a rich solution and purified gas. The purified gas is discharged from the top of the absorption tower 1 to the next process. The rich solution from the bottom of the absorption tower 1 is heated by the lean-rich solution heat exchanger 3 and then enters the upper part of the regeneration tower 5. Inside the regeneration tower 5, it is heated by the bottom boiling vessel 6 to regenerate into a lean solution. The separated carbon dioxide is cooled from the top of the regeneration tower 5 by the second water cooler 7 and then discharged. The lean solution from the bottom of the regeneration tower 5 is pressurized by the lean solution pump 4, cooled by the first water cooler 2, and then enters the upper part of the absorption tower 1.

[0048] In some preferred embodiments of the present invention, the operating conditions in the absorption tower are: pressure 2.3 MPa, gas flow rate 1 Nm³. 3 / h, lean liquid flow rate 2L / h; the operating conditions in the regeneration tower are: regeneration temperature 120℃, regeneration tower pressure 0.05MPa.

[0049] The present invention will be described in detail below through embodiments.

[0050] Unless otherwise specified, all reagents used in the following examples and comparative examples are commercially available.

[0051] The method for preparing activated potassium alkali solution is as follows: dissolve potassium carbonate, amino acid activator, and ionic liquid corrosion inhibitor in water and stir to prepare a solution in the appropriate proportion.

[0052] In the following examples and comparative examples, the performance tests of activating potassium alkali solutions were conducted. Figure 1The decarbonization process is carried out in the oxygen-containing mixed gas decarbonization device shown. Specifically: an activated potassium hydroxide solution is added to the absorption tower 1. An oxygen-containing mixed gas containing different volume contents of carbon dioxide enters the lower part of the absorption tower 1 and comes into countercurrent contact with the activated potassium hydroxide solution entering from the upper and middle parts of the absorption tower 1 to capture carbon dioxide, resulting in a rich solution and a purified gas. The purified gas is discharged from the top of the absorption tower 1. The rich solution from the bottom of the absorption tower 1 is heated by a lean-rich solution heat exchanger 3 and then enters the upper part of the regeneration tower 5. In the regeneration tower 5, it is heated by a bottom boiling device 6 to regenerate into a lean solution. The carbon dioxide is discharged from the top of the regeneration tower 5 after being cooled by a second water cooler 7. The lean solution from the bottom of the regeneration tower 5 is pressurized by a lean solution pump 4, cooled by a first water cooler 2, and then enters the upper part of the absorption tower 1. The absorption performance of the activated potassium hydroxide solution is tested by comparing the volume contents of carbon dioxide in the oxygen-containing mixed gas and the purified gas.

[0053] The operating conditions in the absorption tower are: pressure 2.3 MPa, gas flow rate 1 Nm³. 3 The lean solution flow rate is 2 L / h; the operating conditions in the regeneration tower are: regeneration temperature 120℃, regeneration tower pressure 0.05 MPa. The solution corrosion rate is obtained by static method according to SYT5273-2000 "Performance Evaluation Method of Corrosion Inhibitors for Oilfield Produced Water".

[0054] The antioxidant properties of activated potassium alkali solution were tested by the following method: 200 mL of activated potassium alkali solution was added to a reaction vessel, pure oxygen was introduced to 1.0 MPa, the temperature was raised to 90°C, and the pressure inside the reaction vessel was measured. If the pressure inside the reaction vessel did not decrease within 72 hours, it indicated that the activated potassium alkali solution was resistant to oxidative degradation.

[0055] Example 1

[0056] (1) Composition of activated potassium alkali solution

[0057] Component Content (wt%) Potassium carbonate 10 Glycine 3.5 2-hydroxy-N,N,N-trimethylethanaminium glycinate 0.05 Water 86.45

[0058] The resulting activated potassium alkali solution had a pH of 11.5, was a homogeneous solution, and showed no salt precipitation or exudation.

[0059] (2) Performance test of activating potassium alkali solution

[0060] pass Figure 1 The apparatus was tested in an oxygen-containing gas mixture at a pressure of 2.3 MPa and a temperature of 50°C. The oxygen content in the mixture was 3% by volume and the carbon dioxide content was 2% by volume.

[0061] Experimental results: The volume content of carbon dioxide in the purified gas was 0.5%, and the corrosion rate of the solution was less than 0.02 mm / a.

[0062] 200 mL of the prepared activated potassium alkali solution was added to the reaction vessel, pure oxygen was introduced to 1.0 MPa, and the temperature was raised to 90°C. The pressure of the reaction vessel did not decrease within 72 hours. The activated potassium alkali solution in this embodiment is resistant to oxidative degradation.

[0063] Example 2

[0064] (1) Composition of activated potassium alkali solution

[0065] Component Content (wt%) Potassium carbonate 23 Amino hexanoic acid 3 2-hydroxy-N,N,N-trimethylethanaminium glycinate 0.05 Water 73.95

[0066] The resulting activated potassium alkali solution had a pH of 11.3, was a homogeneous solution, and showed no salt precipitation or exudation.

[0067] (2) Performance test of activating potassium alkali solution

[0068] pass Figure 1 The apparatus was tested in an oxygen-containing gas mixture at a pressure of 2.3 MPa and a temperature of 50°C. The oxygen content in the mixture was 3% by volume and the carbon dioxide content was 2% by volume.

[0069] Experimental results: The volume content of carbon dioxide in the purified gas was 0.2%, and the solution corrosion rate was less than 0.02 mm / a.

[0070] 200 mL of the prepared activated potassium alkali solution was added to the reaction vessel, pure oxygen was introduced to 1.0 MPa, and the temperature was raised to 90°C. The pressure of the reaction vessel did not decrease within 72 hours. The activated potassium alkali solution in this embodiment is resistant to oxidative degradation.

[0071] Example 3

[0072] (1) Composition of activated potassium alkali solution

[0073] Component Content (wt%) Potassium carbonate 25 Glutamic acid 5 2-hydroxy-N,N,N-trimethylethanaminium alaninate 0.1 Water 69.9

[0074] The resulting activated potassium alkali solution had a pH of 11.6, was a homogeneous solution, and showed no salt precipitation or exudation.

[0075] (2) Performance test of activating potassium alkali solution

[0076] pass Figure 1 The apparatus was tested in an oxygen-containing gas mixture at a pressure of 2.3 MPa and a temperature of 50°C. The oxygen content in the mixture was 5% by volume and the carbon dioxide content was 4.5% by volume.

[0077] Experimental results: The volume content of carbon dioxide in the purified gas was 0.1%, and the corrosion rate of the solution was less than 0.02 mm / a.

[0078] 200 mL of the prepared activated potassium alkali solution was added to the reaction vessel, pure oxygen was introduced to 1.0 MPa, and the temperature was raised to 90°C. The pressure of the reaction vessel did not decrease within 72 hours. The activated potassium alkali solution in this embodiment is resistant to oxidative degradation.

[0079] Example 4

[0080] (1) Composition of activated potassium alkali solution

[0081] Component Content (wt%) Potassium carbonate 27 Alanine 3.5 2-hydroxy-N,N,N-trimethylethanaminium alaninate 0.1 Water 69.4

[0082] The prepared activated potassium base solution has a pH of 12.2, is a homogeneous solution, and has no salt precipitation or exudation.

[0083] (2) Performance test of activating potassium alkali solution

[0084] pass Figure 1 The apparatus was tested in an oxygen-containing gas mixture at a pressure of 2.3 MPa and a temperature of 50°C. The oxygen content in the mixture was 5% by volume, and the carbon dioxide content was 5% by volume.

[0085] Experimental results: The volume content of carbon dioxide in the purified gas was 0.5%, and the corrosion rate of the solution was less than 0.02 mm / a.

[0086] 200 mL of the prepared activated potassium alkali solution was added to the reaction vessel, pure oxygen was introduced to 1.0 MPa, and the temperature was raised to 90°C. The pressure of the reaction vessel did not decrease within 72 hours. The activated potassium alkali solution in this embodiment is resistant to oxidative degradation.

[0087] Example 5

[0088] (1) Composition of activated potassium alkali solution

[0089] Component Content (wt%) Potassium carbonate 27 Lysine 5 1 -ethyl-3-methylimidazolium acetate 0.2 Water 67.8

[0090] The resulting activated potassium alkali solution had a pH of 12.6, was a homogeneous solution, and showed no salt precipitation or exudation.

[0091] (2) Performance test of activating potassium alkali solution

[0092] pass Figure 1 The apparatus was tested in an oxygen-containing gas mixture at a pressure of 2.3 MPa and a temperature of 50°C. The oxygen content in the mixture was 5% by volume, and the carbon dioxide content was 5% by volume.

[0093] Experimental results: The volume content of carbon dioxide in the purified gas was 0.5%, and the corrosion rate of the solution was less than 0.02 mm / a.

[0094] 200 mL of the prepared activated potassium alkali solution was added to the reaction vessel, pure oxygen was introduced to 1.0 MPa, and the temperature was raised to 90°C. The pressure of the reaction vessel did not decrease within 72 hours. The activated potassium alkali solution in this embodiment is resistant to oxidative degradation.

[0095] Example 6

[0096] (1) Composition of activated potassium alkali solution

[0097]

[0098]

[0099] The resulting activated potassium alkali solution had a pH of 12.7, was a homogeneous solution, and showed no salt precipitation or exudation.

[0100] (2) Performance test of activating potassium alkali solution

[0101] pass Figure 1 The apparatus was tested in an oxygen-containing gas mixture at a pressure of 2.3 MPa and a temperature of 50°C. The oxygen content in the mixture was 8% by volume and the carbon dioxide content was 3% by volume.

[0102] Experimental results: The volume content of carbon dioxide in the purified gas was 0.2%, and the solution corrosion rate was less than 0.02 mm / a.

[0103] 200 mL of the prepared activated potassium alkali solution was added to a reaction vessel, pure oxygen was introduced to a pressure of 1.0 MPa, and the temperature was raised to 90°C. The pressure in the reaction vessel did not decrease within 72 hours. The activated potassium alkali solution in this embodiment is resistant to oxidative degradation.

[0104] Example 7

[0105] (1) Composition of activated potassium alkali solution

[0106] Component Content (wt%) Potassium carbonate 30 Proline 6 1 -butyl-3-methylimidazolium acetate 0.2 Water 63.8

[0107] The resulting activated potassium alkali solution had a pH of 12.3, was a homogeneous solution, and showed no salt precipitation or exudation.

[0108] (2) Performance test of activating potassium alkali solution

[0109] pass Figure 1 The apparatus was tested in an oxygen-containing gas mixture at a pressure of 2.3 MPa and a temperature of 50°C. The oxygen content in the mixture was 8% by volume and the carbon dioxide content was 6% by volume.

[0110] Experimental results: The volume content of carbon dioxide in the purified gas was 0.2%, and the solution corrosion rate was less than 0.02 mm / a.

[0111] The prepared activated potassium base solution was taken 200 mL and added to a reaction kettle, pure oxygen was introduced to 1.0 MPa, the temperature was raised to 90°C, and the pressure in the reaction kettle did not decrease within 72 hours. The activated potassium base solution prepared in this example was resistant to oxidative degradation.

[0112] Example 8

[0113] The activated potassium base solution was prepared according to the method in Example 1 and performance test was conducted, except that glycine was replaced by tyrosine with the same mass content.

[0114] The prepared activated potassium base solution was a heterogeneous solution with white precipitate at the bottom.

[0115] Comparative Example 1

[0116] The activated potassium base solution was prepared according to the method in Example 1 and performance test was conducted, except that no glycine was added, specifically:

[0117] Component Content (wt%) Potassium carbonate 10 2-hydroxy-N,N,N-trimethylethanaminium glycinate 0.05 Water 89.95

[0118] The prepared activated potassium base solution had a pH value of 11.6 and was a homogeneous solution without salt precipitation and precipitation.

[0119] Test results: the volume content of carbon dioxide in the purified gas was 1%, and the solution corrosion efficiency was less than 0.02 mm / a.

[0120] The prepared activated potassium base solution was taken 200 mL and added to a reaction kettle, pure oxygen was introduced to 1.0 MPa, the temperature was raised to 90°C, and the pressure in the reaction kettle did not decrease within 72 hours.

[0121] Comparative Example 2

[0122] The activated potassium base solution was prepared according to the method in Example 4 and performance test was conducted, except that no alanine was added, specifically:

[0123] Component Content (wt%) Potassium carbonate 27 2-hydroxy-N,N,N-trimethylethanaminium glycinate 0.1 Water 72.9

[0124] The prepared activated potassium base solution had a pH value of 12.1 and was a homogeneous solution without salt precipitation and precipitation.

[0125] Test results: the volume content of carbon dioxide in the purified gas was 0.6%, and the solution corrosion efficiency was less than 0.2 mm / a.

[0126] The prepared activated potassium base solution was taken 200 mL and added to a reaction kettle, pure oxygen was introduced to 1.0 MPa, the temperature was raised to 90°C, and the pressure in the reaction kettle did not decrease within 72 hours.

[0127] Comparative Example 3

[0128] The activated potassium base solution was prepared according to the method in Example 1 and performance test was conducted, except that 2-hydroxy-N,N,N-trimethylammonium propylate was not added, specifically:

[0129] Component Content (wt%) Potassium carbonate 10 Glycine 3.5 Water 86.5

[0130] The prepared activated potassium base solution had a pH value of 11.0 and was a homogeneous solution without salt precipitation and separation. The test results were as follows: the volume content of carbon dioxide in the purified gas was 0.5%, and the solution corrosion rate was 0.06 mm / a.

[0131] The activated potassium base solution was taken 200 mL and added to the reaction kettle, pure oxygen was introduced to 1.0 MPa, and the temperature was raised to 90°C. The pressure in the reaction kettle did not decrease within 72 hours.

[0132] Comparative Example 4

[0133] The activated potassium base solution was prepared according to the method in Example 1 and performance test was conducted, except that 2-hydroxy-N,N,N-trimethylammonium propylate was replaced by 1-butyl-3-methylimidazolium hexafluorophosphate with the same mass content.

[0134] The prepared activated potassium base solution was a heterogeneous solution with stratification.

[0135] Comparative Example 5

[0136] The activated potassium base solution was prepared according to the method in Example 1 and performance test was conducted, except that 2-hydroxy-N,N,N-trimethylammonium propylate was replaced by amine ethyl methyl imidazole tetrafluoroborate with the same mass content.

[0137] The prepared activated potassium base solution had a pH value of 12.1 and was a homogeneous solution without salt precipitation and separation.

[0138] The test results were as follows: the volume content of carbon dioxide in the purified gas was 0.3%, and the solution corrosion rate was less than 0.02 mm / a.

[0139] The activated potassium base solution was taken 200 mL and added to the reaction kettle, pure oxygen was introduced to 1.0 MPa, and the temperature was raised to 90°C. The pressure in the reaction kettle decreased by 15% within 72 hours, and the activated potassium base solution was oxidatively degraded.

[0140] It can be seen from Example 1 and Comparative Examples 4 and 5 that the activated potassium base solution prepared by using the ionic liquid of the present application is a homogeneous solution, without salt precipitation and separation, and is less likely to block the decarbonization system and is resistant to oxidative degradation; while the activated potassium base solution prepared without using the preferred ionic liquid is a heterogeneous solution, has a separation phenomenon or is a homogeneous solution but has an oxidative degradation phenomenon, and is not suitable for removing carbon dioxide from oxygen-containing mixed gas. It can be seen from Comparative Examples 1 and 2 that the activated potassium base solution prepared without adding the amino acid activator has a significantly increased carbon dioxide content in the purified gas, and exceeds the industry index (0.5 vol%), which will result in excessive carbon dioxide content in the oxygen-containing mixed gas and affect the subsequent process. It can be seen from Example 1 and Comparative Example 3 that the corrosion rate of the activated potassium base solution prepared without adding the ionic liquid is significantly increased, indicating that the corrosion inhibition effect of the ionic liquid of the present application is obvious. It can be seen from the test results of the examples and comparative examples that the activated potassium base solution of the present application has higher decarbonization efficiency, less corrosion to carbon steel equipment, low solution toxicity, no salt precipitation and separation, and is less likely to block the decarbonization system. It can be seen from Example 1 and Example 8 that the activated potassium base solution prepared by using the preferred amino acid activator is a homogeneous solution, without salt precipitation and separation, and is less likely to block the decarbonization system; while the activated potassium base solution prepared without using the preferred amino acid activator is a heterogeneous solution.

[0141] The above describes the preferred embodiments of the present application in detail, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including combining various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. An activated potassium alkali solution for removing carbon dioxide from oxygen-containing gases, characterized in that, The solution comprises potassium carbonate, an amino acid activator, an ionic liquid, and water; Wherein, the anion in the ionic liquid is selected from at least one of acetate ions, lactate ions, and amino acid salt ions; the ionic liquid is a methylimidazolium ionic liquid and / or a quaternary ammonium ionic liquid; the amino acid activator is at least one of glycine, aminocaproic acid, glutamic acid, alanine, lysine, arginine, and proline; based on the total amount of the solution, the content of potassium carbonate in the solution is 10-30 wt%, the content of the amino acid activator is 2-10 wt%, the content of the ionic liquid is 0.02-0.45 wt%, and the content of water is 59.55-87.98 wt%.

2. The activated potassium alkali solution according to claim 1, wherein, Based on the total amount of the solution, the content of potassium carbonate is 10-30 wt%, the content of the amino acid activator is 3-6 wt%, the content of the ionic liquid is 0.05-0.2 wt%, and the content of water is 63.8-86.45 wt%.

3. The activated potassium alkali solution according to claim 1, wherein, The ionic liquid is selected from at least one of 2-hydroxy-N,N,N-trimethylethylammonium glycinate, 2-hydroxy-N,N,N-trimethylethylammonium alanine, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium lactate, and 1-butyl-3-methylimidazolium acetate.

4. The activated potassium alkali solution according to any one of claims 1-3, wherein, The pH of the solution is between 11 and 13.

5. The application of the activated potassium alkali solution according to any one of claims 1-4 in removing carbon dioxide from an oxygen-containing gas mixture.

6. A method for removing carbon dioxide from an oxygen-containing gas mixture, characterized in that, The method includes: countercurrently contacting an activated potassium alkali solution with an oxygen-containing mixed gas to capture carbon dioxide, thereby obtaining a rich liquid and a purified gas; wherein the activated potassium alkali solution is the activated potassium alkali solution according to any one of claims 1-4.

7. The method according to claim 6, wherein, The pressure of the oxygen-containing mixture is 2-4 MPa, and the temperature is 50-80℃; Based on the total volume of the oxygen-containing gas mixture, the volume content of oxygen is 3-8% and the volume content of carbon dioxide is 2-6%.

8. The method according to claim 6 or 7, wherein, The method further includes: regenerating the rich solution into a lean solution; and returning the resulting lean solution to the carbon dioxide capture unit.

9. The method according to claim 8, wherein, The regeneration conditions are: temperature 110-130℃, pressure 0.02-0.06MPa.

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