An apparatus for purifying an alcohol amine solution by electrodialysis

Abstract

The application provides a device for purifying alcohol amine solution by electrodialysis, which comprises an anode chamber, a cathode chamber, a concentrated solution chamber and a desalination chamber arranged between the anode chamber and the cathode chamber in sequence, a concentrated solution water tank in closed loop with the concentrated solution chamber through a first pipeline, a desalination water tank in closed loop with the desalination chamber through a second pipeline, the concentrated solution chamber and the desalination chamber being communicated through an anion exchange membrane, and a cation exchange membrane arranged between the desalination chamber and the cathode chamber. The device for purifying alcohol amine solution by electrodialysis has the advantages that the device can remove the heat stable salt in the alcohol amine solution to a mass content of 0.5% or less, and ensure the recovery rate of the organic amine to be 99.99% or more, so that the alcohol amine solution can be purified, and the loss of the alcohol amine solution in the purification process is reduced.

Description

Technical Field

[0001] This invention belongs to the field of solution purification technology, specifically relating to an apparatus for purifying alkanolamine solutions via electrodialysis. Background Technology

[0002] Greenhouse gases are exacerbating global warming, causing a series of environmental problems such as glacial melting and rising sea levels, and significantly increasing the intensity and frequency of extreme weather events. CO2, as the most significant greenhouse gas, has received widespread attention worldwide; therefore, carbon dioxide emission reduction has become a crucial consensus among countries worldwide in addressing climate change. Carbon capture, utilization, and storage (CCUS) technology, as an important pathway to achieving carbon neutrality, has become one of the focal points of research in the field of carbon neutrality.

[0003] CO2 capture, as the primary step in CCUS (Carbon Dioxide Capture and Removal), has been implemented in numerous large-scale facilities both domestically and internationally. Absorption is currently the most widely used method in industry, and among various absorbents, alkanolamine absorbents offer high efficiency, mature technology, and high selectivity. However, alkanolamine solutions undergo degradation during recycling, and many degradation products are highly volatile, leading to increased solution consumption and energy expenditure. This is extremely detrimental to environmental safety and maintaining long-term CO2 capture efficiency. Among the various degradation products in alkanolamine solutions, heat-stable salts, primarily composed of organic acid anions, constitute a significant proportion and represent a major area of ​​research and development in the field. Summary of the Invention

[0004] This application provides an apparatus for purifying an alkanolamine solution by electrodialysis, which aims to solve the problem of low efficiency in removing heat-stable salts from alkanolamine solutions in the prior art.

[0005] This application provides an apparatus for purifying an alkanolamine solution by electrodialysis, comprising an anode chamber, a cathode chamber, a concentrate chamber and a desalination chamber sequentially disposed between the anode chamber and the cathode chamber;

[0006] A concentrate tank that forms a closed loop with the concentrate chamber through a first pipe;

[0007] A desalination liquid tank that forms a closed loop with the desalination chamber through a second pipe;

[0008] The concentrate chamber and the desalination chamber are connected by an anion exchange membrane, and a cation exchange membrane is provided between the desalination chamber and the cathode chamber.

[0009] During the purification of a amine solution containing heat-stable salts using the apparatus described in this application, negatively charged HSS in the amine solution within the desalination chamber migrates through the anion exchange membrane to the positive electrode under the influence of a DC electric field, entering the concentrate chamber. There, it is intercepted by a monovalent selective cation exchange membrane and remains in the concentrate chamber. Sodium ions in the amine solution pass through the cation exchange membrane into the concentrate. Organic amines and hydroxide ions remain in the desalination chamber. This process continues under electrical drive until the HSS in the amine solution is completely removed. Simultaneously, organic amines in the amine are blocked by the anion exchange membrane and almost entirely retained in the desalination chamber by the smaller-pore monovalent selective cation exchange membrane. As the operating time increases, HSS in the amine solution continuously flows from the desalination solution into the concentrate, achieving the effect of removing heat-stable salts from the amine solution and ultimately completing the purification of the amine solution.

[0010] According to some embodiments of the electrodialysis purification apparatus for amine solutions described in this application, the desalination tank stores amine solution containing heat-stable salts.

[0011] According to some embodiments of the electrodialysis apparatus for purifying amine solutions described in this application, the concentrate tank contains water.

[0012] According to some embodiments of the electrodialysis purification apparatus for amine solutions described in this application, the apparatus further includes an electrode liquid tank, which forms a closed loop with the anode chamber and the cathode chamber respectively.

[0013] According to some embodiments of the electrodialysis purification apparatus for amine solutions described in this application, the solution in the electrode tank is a sodium sulfate solution with a mass concentration of 2%-4%.

[0014] According to some embodiments of the electrodialysis purification apparatus for amine solutions described in this application, the solution in the electrode tank is a sodium sulfate solution with a mass concentration of 3%.

[0015] According to some embodiments of the electrodialysis purification apparatus for amine solution described in this application, the apparatus further includes a recycled water tank for storing the purified amine solution, and the recycled water tank is connected to the desalination tank via a pump.

[0016] According to some embodiments of the electrodialysis purification apparatus for amine solutions described in this application, both the first pipeline and the second pipeline are equipped with a water pump and a regulating valve.

[0017] The beneficial effects of this application include: the electrodialysis purification apparatus for amine solutions described in this application can remove heat-stable salts from amine solutions to a mass content of less than 0.5%, and ensure that the recovery rate of organic amines is above 99.99%. It can not only purify amine solutions, but also reduce the loss of amine solutions during the purification process. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the electrodialysis device for purifying alkanolamine solution described in this application;

[0019] In the diagram: 1. Cathode chamber, 2. Anode chamber, 3. Concentrate chamber, 4. Desalination chamber, 5. Concentrate tank, 6. Desalination tank, 7. Electrode tank, 8. Reclaimed water tank. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0021] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0022] This application provides an apparatus for purifying an alkanolamine solution by electrodialysis, comprising an anode chamber, a cathode chamber, a concentrate chamber and a desalination chamber sequentially disposed between the anode chamber and the cathode chamber;

[0023] A concentrate tank that forms a closed loop with the concentrate chamber through a first pipe;

[0024] A desalination liquid tank that forms a closed loop with the desalination chamber through a second pipe;

[0025] The concentrate chamber and the desalination chamber are connected by an anion exchange membrane, and a cation exchange membrane is provided between the desalination chamber and the cathode chamber.

[0026] When the alkanolamine solution flows into the desalination chamber from the desalination tank, under the influence of a DC electric field, the anions and cations in the alkanolamine solution undergo directional migration: the thermally stable salts move towards the anode, and the organic amines move towards the cathode. The hydrolyzed cations of the multivalent organic amines, during their migration towards the cathode, encounter the smaller pores of the cation exchange membrane and are retained. The negatively charged anions of the thermally stable salts pass through the anion exchange membrane into the concentrate chamber.

[0027] In some embodiments of this application, the desalination tank stores an amine solution containing a heat-stable salt, and the desalination tank and the desalination chamber are connected by a water pump. A flow meter, pressure gauge, and regulating valve are installed on the pipe connecting the desalination tank and the desalination chamber. The amine solution in the desalination tank is pumped to the desalination chamber by the water pump, undergoes ion exchange under the action of a DC electric field, and then returns to the desalination tank.

[0028] In some embodiments of this application, the concentrate tank stores water. The concentrate tank and the concentrate chamber are connected by a pipeline, and a pump, flow meter, pressure gauge, and regulating valve are installed in the connection loop. The initial solution in the concentrate tank is water, and as ion exchange occurs, thermally stable salts and sodium ions gradually enter the concentrate.

[0029] In some embodiments of this application, the device further includes an electrode liquid tank, which forms a closed loop with the anode chamber and the cathode chamber respectively. The electrode liquid tank forms a connection loop with the anode chamber and the cathode chamber respectively, and a pump, a flow meter, a pressure gauge and a regulating valve are provided on the connection loop.

[0030] In some embodiments of this application, the solution in the polar liquid tank is a sodium sulfate solution with a mass concentration of 2%-4%.

[0031] In some embodiments of this application, the solution in the polar liquid tank is a sodium sulfate solution with a mass concentration of 3%.

[0032] In some embodiments of this application, the device further includes a recycled water tank for storing purified amine solution, and the recycled water tank is connected to the desalination solution tank via a pump.

[0033] In some embodiments of this application, both the first pipe and the second pipe are equipped with a water pump and a regulating valve.

[0034] The technical solution of this application will be further described below with reference to specific embodiments.

[0035] An electrodialysis device for purifying an alcohol amine solution includes an anode chamber 2, a cathode chamber 1, a concentrate chamber 3 and a desalination chamber 4 sequentially disposed between the anode chamber 2 and the cathode chamber 1; a concentrate tank 5 forming a closed loop with the concentrate chamber 3 through a first pipe; and a desalination tank 6 forming a closed loop with the desalination chamber 4 through a second pipe. The concentrate chamber 3 and the desalination chamber 4 are connected by an anion exchange membrane, and a cation exchange membrane is disposed between the desalination chamber 4 and the cathode chamber 1.

[0036] Amine solution containing heat-stable salts is stored in desalination tank 6, water is stored in concentrate tank 5, cathode chamber 1 and anode chamber 2 form closed loops with electrode liquid tank 7, and sodium sulfate solution with a mass concentration of 3% is stored in electrode liquid tank 7.

[0037] During operation, when a solution of heat-stable amines containing heat-stable salts enters the desalination chamber 4 from the desalination tank 6 via a pump, under the influence of a DC electric field, the anions and cations in the amine solution undergo directional migration. Specifically, the heat-stable salts move towards the anode, and the organic amines move towards the cathode. The hydrolyzed cations of the multivalent organic amines encounter the smaller pores of the cation exchange membrane along their migration path and are almost completely retained. The negatively charged heat-stable salt anions (HSS-) pass through the anion exchange membrane into the concentration chamber. The solution collected in the concentration chamber flows into the concentrate tank via a pump.

[0038] The device described in this application also includes a recycled water tank 8, which is connected to a desalination liquid tank 6 via a pump. A valve and a flow meter are installed on the pipeline connecting the recycled water tank 8 and the desalination liquid tank 6. The recycled water tank 8 is used to store the purified amine solution.

[0039] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. An apparatus for purifying an alkanolamine solution via electrodialysis, characterized in that, It includes an anode chamber, a cathode chamber, a concentrate chamber and a desalination chamber arranged sequentially between the anode chamber and the cathode chamber; A concentrate tank that forms a closed loop with the concentrate chamber through a first pipe; A desalination liquid tank that forms a closed loop with the desalination chamber through a second pipe; The concentrate chamber and the desalination chamber are connected by an anion exchange membrane, and a cation exchange membrane is provided between the desalination chamber and the cathode chamber.

2. The apparatus for purifying alkanolamine solution by electrodialysis according to claim 1, characterized in that, The desalination tank contains amine solution containing heat-stable salts.

3. The apparatus for purifying alkanolamine solution by electrodialysis according to claim 1, characterized in that, The concentrate tank contains water.

4. The apparatus for purifying alkanolamine solution by electrodialysis according to claim 1, characterized in that, The device also includes an electrode liquid tank, which forms a closed loop with the anode chamber and the cathode chamber respectively.

5. The apparatus for purifying alkanolamine solution by electrodialysis according to claim 3, characterized in that, The solution in the polar liquid tank is a sodium sulfate solution with a mass concentration of 2%-4%.

6. The apparatus for purifying alkanolamine solution by electrodialysis according to claim 3, characterized in that, The solution in the polar liquid tank is a sodium sulfate solution with a mass concentration of 3%.

7. The apparatus for purifying alkanolamine solution by electrodialysis according to claim 1, characterized in that, The device also includes a recycled water tank for storing purified amine solution, and the recycled water tank is connected to the desalination solution tank via a pump.

8. The apparatus for purifying alkanolamine solution by electrodialysis according to claim 1, characterized in that, Both the first and second pipelines are equipped with water pumps and regulating valves.

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