Diethylene glycol amine-polyol eutectic solvent carbon dioxide absorbent, method of making and use thereof
Patent Information
- Application Number
- CN202611472238.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-09-21
- Publication Date
- 2026-11-03
AI Technical Summary
Existing carbon dioxide absorbents suffer from problems such as high regeneration energy consumption, easy solvent volatility, and equipment corrosion. Furthermore, the absorption performance and stability of existing eutectic solvent systems need to be improved.
A low-volatility, high-efficiency carbon dioxide absorbent is formed by using a eutectic solvent composed of diethylene glycolamine and polyol, adjusting the molar ratio of diethylene glycolamine to polyol, and adding piperazine and water. The preparation method is simple and suitable for carbon dioxide capture and separation.
It achieves high-efficiency carbon dioxide absorption performance, reduces regeneration energy consumption, reduces solvent volatility, and improves the stability and absorption capacity of the absorbent, making it suitable for high-load carbon dioxide capture at room temperature.
Smart Images
Figure CN123024418A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of carbon dioxide capture and separation technology, and in particular to a eutectic solvent carbon dioxide absorbent with diethylene glycolamine and polyol as the main components, its preparation method and application. Background Technology
[0002] Carbon dioxide capture and separation is a crucial technological step in reducing carbon emissions. Among existing technologies, aqueous solutions of alcoholic amines, especially monoethanolamine (MEA), are widely used due to their fast reaction rates. However, these systems typically suffer from high regeneration energy consumption, solvent evaporation losses, equipment corrosion, and high operating and maintenance costs.
[0003] In recent years, novel carbon dioxide capture systems, such as solid adsorbents, ionic liquids, eutectic solvents, and solid-liquid two-phase absorbents, have been extensively studied. Solid adsorbents, such as metal-organic frameworks and zeolites, have certain potential under specific conditions, but in actual industrial flue gas, water vapor, acidic gases, and other impurities can easily affect their adsorption capacity and cycle stability; some low-energy absorption systems may also suffer from engineering problems such as increased viscosity, limited mass transfer, or difficulty in phase separation.
[0004] Deep eutectic solvents (DES) are typically formed by hydrogen bonding between hydrogen bond donors and acceptors, and are characterized by simple preparation, low volatility, high designability, and environmental friendliness. Yan et al. (Superbase Ionic Liquid-Based Deep Eutectic Solvents for Improving CO2 Absorption) prepared a [HDBU][Im] / EG eutectic solvent with a mass ratio of 7:3, achieving a CO2 absorption capacity of 0.141 g CO2 / g DES at 40 °C. Cui et al. (Efficient CO2 Absorption by Azolide-Based Deep Eutectic Solvents) used a [N] eutectic solvent with a molar ratio of 1:2... 2222 [Im] / EG is a eutectic solvent with an absorption capacity of 0.129 g CO2 / g solvent at 25℃. Cao Ziyi (research on amine-based eutectic solvents for CO2 absorption) prepared Thy-MEA, which has an absorption capacity of 0.1641 g CO2 / g DESs at 30℃. Combining amines with carbon dioxide chemical reactivity with polyols to form eutectic solvents holds promise for maintaining the efficient carbon dioxide capture capacity of amines while utilizing the hydrogen bonding network formed by polyols to regulate the system properties, thereby obtaining a green carbon dioxide absorbent with high absorption capacity, low volatility, and good stability.
[0005] Therefore, it is necessary to provide a eutectic solvent system that is readily available, simple to prepare, has low volatility, and is suitable for carbon dioxide capture and separation. Currently, diethylene glycol amines (DGAs) have attracted widespread attention due to their low toxicity and low volatility, and are considered a major component of carbon dioxide absorbents. However, the above research results show that the absorption performance, rich liquid viscosity, and absorption energy consumption of DGA-based absorption systems still need further improvement. Summary of the Invention
[0006] This invention provides a diethylene glycol amine-polyol eutectic solvent carbon dioxide absorbent, its preparation method, and its applications. It solves the problems of high regeneration energy consumption, solvent volatility, and equipment corrosion associated with existing carbon dioxide absorbents, and improves carbon dioxide absorption performance.
[0007] A diethylene glycolamine-polyol eutectic solvent carbon dioxide absorbent, wherein the carbon dioxide absorbent is a eutectic solvent comprising diethylene glycolamine and a polyol, wherein the polyol is one of ethylene glycol, glycerol, 1,2-propanediol, and 1,4-butanediol, and the molar ratio of diethylene glycolamine to the polyol is (2-7):1.
[0008] When the polyol is ethylene glycol, 1,2-propanediol, or 1,4-butanediol, the molar ratio of diethylene glycolamine to polyol is (2-5):1; when the polyol is glycerol, the molar ratio of diethylene glycolamine to polyol is 7:1.
[0009] The absorbent also contains piperazine, diethylene glycolamine, and the molar ratio of the polyol to piperazine is (2-7):1:(0.6-1).
[0010] The absorbent also contains water, the mass of which does not exceed 30% of the total mass of the absorbent; preferably, the mass of the water is 10%-30% of the total mass of the absorbent.
[0011] The carbon dioxide absorbent of the present invention has a carbon dioxide absorption loading of 0.35-0.46 molCO2 / molDGA at room temperature.
[0012] This invention also provides a method for preparing a diethylene glycolamine-polyol eutectic solvent carbon dioxide absorbent, comprising the following steps: weighing diethylene glycolamine and polyol, and / or piperazine according to the specified ratio; mixing the above raw materials; heating to 50-90°C and stirring for 1-6 hours until a homogeneous eutectic solvent is formed. After the eutectic solvent is formed, it is left at room temperature for 24-72 hours to confirm that no crystal precipitation or liquid phase separation occurs.
[0013] This invention also provides a method for preparing a diethylene glycolamine-polyol eutectic solvent carbon dioxide absorbent, comprising the following steps: weighing diethylene glycolamine and polyol, and / or piperazine according to the specified ratio; mixing the above raw materials; heating to 50-90°C and stirring for 1-6 hours until a homogeneous eutectic solvent is formed; allowing the eutectic solvent to stand at room temperature for 24-72 hours after its formation to confirm that no crystal precipitation or liquid phase separation occurs; adding water to the eutectic solvent absorbent prepared above; and continuously stirring until a homogeneous transparent solution is formed.
[0014] The preferred heating temperature in the preparation method is 70°C, and the stirring time is 2 hours.
[0015] The present invention also provides the application of the above-mentioned absorbent in carbon dioxide capture and separation.
[0016] The present invention also provides a carbon dioxide capture method, wherein carbon dioxide-containing gas is contacted with the above-mentioned absorbent, so that the carbon dioxide is absorbed by the carbon dioxide absorbent; the carbon dioxide-containing gas includes flue gas after power plant combustion and industrial flue gas with a carbon dioxide concentration of 15-20%.
[0017] The beneficial effects of adopting the above technical solution are as follows:
[0018] The amine groups in the diethylene glycol amine molecule in the eutectic solvent can undergo a reversible chemical reaction with carbon dioxide, thereby achieving highly efficient and selective capture of carbon dioxide. The polyols can participate in the construction of hydrogen bond networks, which is beneficial for adjusting the system viscosity and mass transfer performance. The eutectic solvent system of this invention avoids the regeneration heat load caused by using a large amount of water as a solvent, and has the potential to reduce desorption energy consumption. The raw materials are readily available, the preparation method is simple, and the volatility is low, making it easy for industrial scale-up applications. The carbon dioxide absorbent of this invention can achieve a carbon dioxide absorption load of 0.176 gCO2 / gDES at room temperature, which is higher than the DGA system in all literature. While possessing good absorption effect, it fully utilizes the advantages of diethylene glycol amine itself being low in toxicity and low in volatility, and the moisture inside the carbon capture device has a low impact on its absorption effect. The content ratio of diethylene glycol amine and different polyols can be adjusted at any time to fully utilize the advantages of each component. The diethylene glycol amine-ethylene glycol absorbent, while exhibiting good absorption effect, also possesses excellent desorption effect, with a desorption rate of 93.08% at 110℃, demonstrating good regeneration performance. Attached Figure Description
[0019] Figure 1 The absorption kinetics curves and total loading of carbon dioxide absorbents in different proportions of diethylene glycol amine-ethylene glycol eutectic solvents are presented.
[0020] Figure 2 The absorption kinetics curves and total loading of carbon dioxide absorbents in diethylene glycolamine-glycerol eutectic solvents with different proportions are shown.
[0021] Figure 3 The absorption kinetics curves and total loading of carbon dioxide absorbents in different proportions of diethylene glycolamine-1,4-butanediol eutectic solvent are presented.
[0022] Figure 4 The absorption kinetics curves and total loading of carbon dioxide absorbents in different proportions of diethylene glycolamine-1,2-propanediol eutectic solvents are presented.
[0023] Figure 5 Absorption kinetics curves and total loading of carbon dioxide absorbents in different proportions of diethylene glycolamine-ethylene glycol-piperazine eutectic solvent.
[0024] Figure 6 The absorption kinetics curves and total loading of the diethylene glycol-ethylene glycol eutectic solvent carbon dioxide absorbent are shown for different water contents.
[0025] Figure 7 The results are infrared spectral measurements of EG, DGA, and EG-DGA (1:4). Detailed Implementation
[0026] Example 1
[0027] Weigh 26.83 g of diethylene glycol and 3.17 g of ethylene glycol, place them in a beaker, and then place the beaker in an oil bath. Heat and stir at 70 °C for 3 hours to obtain a diethylene glycol-ethylene glycol eutectic solvent. After preparation, the absorbent was left at room temperature for 48 hours, and no obvious small crystal precipitation or liquid phase separation was observed. The prepared eutectic solvent was added to an absorption flask, and carbon dioxide gas was introduced at room temperature for absorption. The carbon dioxide loading at the absorption endpoint was approximately 0.17 g CO2 / g DES.
[0028] Example 2
[0029] Weigh 26.66 g of diethylene glycolamine and 3.34 g of glycerol, place them in a beaker, and then place the beaker in an oil bath. Heat and stir at 70 °C for 3 hours to obtain a diethylene glycolamine-glycerol eutectic solvent. After preparation, the absorbent was left at room temperature for 48 hours, and no obvious small crystal precipitation or liquid phase separation was observed. The prepared eutectic solvent was added to an absorption flask, and carbon dioxide gas was introduced at room temperature for absorption. The carbon dioxide loading at the absorption endpoint was approximately 0.14 g CO2 / g DES.
[0030] Example 3
[0031] 25.61 g of diethylene glycolamine and 4.39 g of 1,4-butanediol were weighed and placed in a beaker, which was then placed in an oil bath. The mixture was heated and stirred at 70 °C for 3 hours to obtain a diethylene glycolamine-1,4-butanediol eutectic solvent. After preparation, the absorbent was left at room temperature for 48 hours, and no obvious small crystal precipitation or liquid phase separation was observed. The prepared eutectic solvent was added to an absorption flask, and carbon dioxide gas was introduced at room temperature for absorption. The carbon dioxide loading at the absorption endpoint was approximately 0.15 g CO2 / g DES.
[0032] Example 4
[0033] 26.21 g of diethylene glycolamine and 3.79 g of 1,2-propanediol were weighed and placed in a beaker, which was then placed in an oil bath. The mixture was heated and stirred at 70 °C for 3 hours to obtain a diethylene glycolamine-1,2-propanediol eutectic solvent. After preparation, the absorbent was left at room temperature for 48 hours, and no obvious small crystal precipitation or liquid phase separation was observed. The prepared eutectic solvent was added to an absorption flask, and carbon dioxide gas was introduced at room temperature for absorption. The carbon dioxide loading at the absorption endpoint was approximately 0.15 g CO2 / g DES.
[0034] Example 5
[0035] 22.18 g of diethylene glycolamine, 3.27 g of ethylene glycol, and 4.54 g of piperazine were weighed and placed in a beaker. The beaker was then placed in an oil bath and heated and stirred at 70 °C for 3 hours to obtain a diethylene glycolamine-ethylene glycol-piperazine eutectic solvent. After preparation, the absorbent was left at room temperature for 48 hours, and no obvious small crystal precipitation or liquid phase separation was observed. The prepared eutectic solvent was added to an absorption flask, and carbon dioxide gas was introduced at room temperature for absorption. The carbon dioxide loading at the absorption endpoint was 0.176 g CO2 / g DES.
[0036] Example 6
[0037] Weigh 26.14 g of diethylene glycolamine and 3.86 g of ethylene glycol, place them in a beaker, and then place the beaker in an oil bath. Heat and stir at 70 °C for 3 hours to obtain a diethylene glycolamine-ethylene glycol eutectic solvent. After preparation, the absorbent was left at room temperature for 48 hours, and no obvious small crystal precipitation or liquid phase separation was observed. Add 2 g of water to 18 g of absorbent, and then add the prepared absorbent to an absorption bottle. Absorption was performed by passing prepared carbon dioxide gas through the bottle at room temperature. The carbon dioxide loading at the absorption endpoint was 0.164 g CO2 / g DES.
[0038] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any equivalent substitutions or improvements made within the spirit and principles of the present invention, such as the ratio of diethylene glycolamine to polyol, the specific type of polyol, the preparation temperature, the stirring time, the composition of the absorption gas, or the absorption operating conditions, should be included within the scope of protection of the present invention.
Claims
1. A diethylene glycol amine-polyol eutectic solvent carbon dioxide absorbent, characterized in that, The carbon dioxide absorbent is a eutectic solvent comprising diethylene glycolamine and a polyol, wherein the polyol is one of ethylene glycol, glycerol, 1,2-propanediol, and 1,4-butanediol, and the molar ratio of diethylene glycolamine to the polyol is (2-7):
1.
2. The carbon dioxide absorbent according to claim 1, characterized in that, The absorbent also contains piperazine, diethylene glycolamine, and the molar ratio of the polyol to piperazine is (2-7):1:(0.6-1).
3. The diethylene glycolamine-polyol eutectic solvent carbon dioxide absorbent according to claim 1 or 2, characterized in that, The absorbent also contains water, the mass of which does not exceed 30% of the total mass of the absorbent.
4. The diethylene glycolamine-polyol eutectic solvent carbon dioxide absorbent according to claim 3, characterized in that, The mass of water is 10%-30% of the total mass of the absorbent.
5. The method for preparing the diethylene glycolamine-polyol eutectic solvent carbon dioxide absorbent according to claim 1 or 2, characterized in that, The process includes the following steps: weighing diethylene glycolamine and polyol, and / or piperazine according to the specified ratio, mixing the above raw materials, heating and stirring until a homogeneous eutectic solvent is formed.
6. The method for preparing the diethylene glycolamine-polyol eutectic solvent carbon dioxide absorbent according to claim 4, characterized in that, The process includes the following steps: weighing diethylene glycolamine and polyol, and / or piperazine according to the specified ratio, mixing the above raw materials, heating and stirring until a homogeneous eutectic solvent is formed, adding water to the prepared eutectic solvent, and continuing to stir until a homogeneous transparent solution is formed.
7. The application of the carbon dioxide absorbent prepared according to claim 5 in carbon dioxide capture and separation.
8. The application of the carbon dioxide absorbent prepared according to claim 6 in carbon dioxide capture and separation.
9. A method for capturing carbon dioxide, characterized in that, The carbon dioxide-containing gas is contacted with the carbon dioxide absorbent prepared according to claim 5 or 6, so that the carbon dioxide is absorbed by the carbon dioxide absorbent; the carbon dioxide-containing gas includes flue gas after power plant combustion or industrial flue gas with a carbon dioxide concentration of 15-20%.