Amine low-water-content absorbent for capturing carbon dioxide and application of amine low-water-content absorbent

Abstract

The invention provides an amine low-water-content absorbent for capturing carbon dioxide and application of the amine low-water-content absorbent. The amine low-water absorbent comprises, by mass, 20%-50% of an absorbent main agent, 35%-70% of an auxiliary solvent and 2%-20% of water, and the range of a solvent effect factor delta of the amine low-water absorbent is 0.28-0.32. According to the method, the composition of the water-less absorbent is screened and optimized through a solvent effect factor formula, the amine water-less absorbent which is easy to desorb, low in regeneration energy consumption and low in viscosity characteristic is obtained, and wide application of the amine water-less absorbent in a carbon capture technology is promoted.

Description

Technical Field

[0001] The invention relates to the technical field of capturing carbon dioxide by chemical absorption, and in particular to an amine low-water absorbent for capturing carbon dioxide and application thereof. Background Art

[0002] The large-scale emission of CO2 is the key reason for the intensification of the greenhouse effect. As a major carbon emitter, my country must control carbon emissions to achieve the "dual carbon" goal, ensure national energy security, and build an energy power. Among the many CO2 emission reduction technology routes, CO2 capture, utilization and storage are considered to be an indispensable technology route for achieving emission reduction targets at this stage, and are crucial to achieving global net zero emissions by 2070.

[0003] Chemical absorption is the most mature and most promising carbon capture technology. Among them, amine absorbents are the most typical and widely studied homogeneous absorbents. Their biggest advantage is that they can be directly operated in existing CO2 capture devices without the need for process modification, which greatly reduces the system process cost.

[0004] CN116139657A discloses an amine non-aqueous absorbent for carbon dioxide capture, the composition and mass percentage of which are 20-30% of the main absorbent, 3-9% of the auxiliary absorbent, and the rest of the composite solvent; wherein the composite solvent is composed of a mixture of polyols and organic alcohol ethers, and the mass ratio of the polyols to the organic alcohol ethers is (2-5): (5-2). The main absorbent is one or more of N-(2-hydroxyethyl)ethylenediamine, N-aminoethylpiperazine, and diethylenetriamine; the auxiliary absorbent is 2-amino-2-methyl-1-propanol and / or piperazine. The polyol in the composite solvent is one of ethylene glycol, diethylene glycol, and glycerol, and the organic alcohol ether is one of ethylene glycol monomethyl ether, ethylene glycol ethyl ether, and ethylene glycol monopropyl ether. However, although the use of non-aqueous solvent absorbents for CO2 capture can reduce solvent volatility, corrosivity, and regeneration energy consumption, there is still a problem of high regeneration energy consumption, which may limit its promotion in industrial applications.

[0005] CN110448993A discloses an organic amine low-water absorbent for capturing carbon dioxide. The organic amine low-water absorbent includes 30%-55% of chain diamine, 40%-67% of auxiliary solvent and 2%-15% of water by mass fraction. The main agent of the organic amine low-water absorbent is N,N-dimethylethylenediamine or N,N-dimethylpropylenediamine or a combination of the two, and the auxiliary solvent is N-methylpyrrolidone. Although the absorbent can greatly reduce the sensible heat and latent heat energy consumption of water due to its unique "low water" characteristic, thereby achieving the purpose of reducing operating energy consumption, it still has disadvantages such as poor cycle stability and relatively high regeneration energy consumption.

[0006] CN110152454A discloses a ternary non-aqueous phase absorption system composed of 2-amino-2-methyl-1-propanol, hydroxyethylethylenediamine and N-methylpyrrolidone, which is used to absorb pure CO2 or CO2 with a volume fraction of 5-20% in a mixed gas; in this ternary system, the molar ratio of 2-amino-2-methyl-1-propanol to hydroxyethylethylenediamine is 4-6:1, the remainder is N-methylpyrrolidone, and the concentration of 2-amino-2-methyl-1-propanol is 1-3 mol / L. The absorbent has good absorption performance and excellent mass transfer performance, but the boiling points of the organic amine and organic solvent used are too low, which greatly reduces the stability of the absorbent and causes certain cost losses in actual industrial production.

[0007] The high regeneration energy consumption and high viscosity of traditional carbon dioxide capture methods have become limiting factors for large-scale industrial use. High regeneration energy consumption means that a large amount of energy is consumed during the absorbent regeneration process, increasing the energy consumption cost of the entire carbon capture process; while high viscosity may cause the absorbent's flow performance in the system to decrease, affecting the absorption efficiency, and may even cause equipment blockage and other problems, increasing the energy consumption and economic cost of the amine absorbent regeneration process, making it unsuitable for large-scale industrial applications in industrial flue gas and coal-fired power plants. Therefore, overcoming the technical barriers of existing amine absorbents such as difficult desorption, high regeneration energy consumption and high viscosity is a technical problem that needs to be solved urgently. Summary of the invention

[0008] In order to solve the above problems, the present invention provides an amine low-water absorbent for capturing carbon dioxide. The composition of the low-water absorbent is screened and optimized through the solvent effect factor formula, thereby determining a specific absorbent main agent and auxiliary solvent, and obtaining an amine low-water absorbent with easy desorption, low regeneration energy consumption and low viscosity characteristics, thereby promoting its wide application in carbon capture technology.

[0009] The technical solution of the present invention is as follows: The present invention provides an amine low-water absorbent for capturing carbon dioxide. The amine low-water absorbent comprises, by mass percentage, 20% to 50% of an absorbent main agent, 35% to 70% of an auxiliary solvent and 2% to 20% of water. The range of the solvent effect factor δ of the amine low-water absorbent is 0.28 to 0.32, and the solvent effect factor satisfies the following formula 1 and formula 2: ; ; in, i It can be expressed as any one of N, M and H2O; N represents the main absorbent, N XExpressed as the xth absorbent main agent, wherein x is an integer greater than zero, and the absorbent main agent is one or a mixture of two or more; M represents auxiliary solvent, M y Expressed as the yth auxiliary solvent, wherein y is an integer greater than zero, and the auxiliary solvent is one or a mixture of two or more; Each represents the absorbent main agent N1, N2, 、N X The density of the absorbent (i.e., the density of the absorbent main agent itself before being formulated into an amine-based water-saving absorbent), in g / L; Respectively represent the auxiliary solvents M1, M2, 、M X The density of (i.e., the density of the auxiliary solvent itself before being formulated into an amine-based water-saving absorbent), in g / L; Expressed as the density of water in g / L; It is expressed as the sum of the densities of all absorbent main agents, auxiliary solvents and water; The result of formula 1 is expressed in L / g, where i When N, M or H2O respectively, They are , , , wherein the mass of the amine water-saving absorbent is taken as the basis, is the mass percentage of the main absorbent, is the mass percentage of auxiliary solvent, is the mass percentage of water, calculated based on formula 1 , ; ρ 总 is the density of the amine-based water-saving absorbent, in g / L; δ is the solvent effect factor of the amine water-saving absorbent.

[0010] Furthermore, the viscosity of the amine low-water absorbent is 8-10 mPa·s.

[0011] Furthermore, the CO2 absorption load of the amine-based water-saving absorbent is 2.70-2.90 mol / kg, the CO2 desorption load is 2.25-2.40 mol / kg, and the regeneration efficiency is 80-86%.

[0012] Further preferably, the CO2 absorption load of the amine-based water-saving absorbent is 2.75-2.85 mol / kg, the CO2 desorption load is 2.29-2.36 mol / kg, and the regeneration efficiency is 82-84%.

[0013] Further, the chain diamine is selected from at least one of the following:

[0014] Furthermore, the auxiliary solvent is selected from at least one of the following:

[0015] The present invention also provides an application of the above-mentioned amine-based water-reducing absorbent, wherein the application comprises using the amine-based water-reducing absorbent to capture carbon dioxide, comprising the following steps: 1) Preparation of amine low water absorbent: Dissolving the auxiliary solvent and water in the absorbent main agent and stirring until a homogeneous phase is obtained to obtain the organic amine low-water absorbent; 2) Check the air tightness and stability of the device: When the absorption bottle is empty, open the valve of the carbon dioxide cylinder to release CO2 through the pressure reducing valve, set the inlet flow rate of carbon dioxide through the mass flow controller and the gas mass flow meter, and then measure the outlet flow rate of carbon dioxide with a soap film flowmeter; 3) Turn off the carbon dioxide inlet, turn on the heat-collecting constant temperature heating magnetic stirrer, and heat the water bath to the absorption temperature of carbon dioxide; 4) After the absorption temperature is constant, weigh the amine-based water-saving absorbent and place it in the absorption bottle, and then place the absorption bottle in the heat-collecting constant-temperature heating magnetic stirrer for constant temperature heating; 5) Open the carbon dioxide inlet and pass it into the absorption bottle containing the amine-based water-saving absorbent, start timing, and record the carbon dioxide outlet flow rate every certain period of time. After the absorption is completed, a carbon dioxide-rich liquid is obtained.

[0016] Furthermore, in step 1), the stirring time is 1 to 2 hours.

[0017] Furthermore, in step 2), the volume concentration of the released CO2 is 99.99%.

[0018] Furthermore, in step 2), the inlet flow rate of the carbon dioxide is set to 100-140 mL / min.

[0019] Furthermore, in step 2), the outlet flow rate of the carbon dioxide is set to 100-140 mL / min.

[0020] Furthermore, in step 3), the rotation speed of the heat collecting constant temperature heating magnetic stirrer is set to 100-140 rpm.

[0021] Furthermore, in step 3), the absorption temperature is 303~323K.

[0022] Furthermore, in step 4), the temperature of the constant temperature heating is the same as the absorption temperature in step 3).

[0023] Furthermore, in step 5), the flow rate of carbon dioxide introduced into the absorption bottle is 100-140 mL / min.

[0024] Furthermore, in step 5), samples are taken every 0, 5, 10, 20, 30, 40, 50 and 60 minutes, and the outlet flow rate of carbon dioxide is recorded.

[0025] Furthermore, in step 5), the constant temperature of the carbon dioxide gas is achieved by partially circling the gas carrier steel pipe in a heat-collecting constant temperature heating magnetic stirrer; Furthermore, the application further comprises desorbing the amine-based water-saving absorbent after the carbon dioxide is captured, comprising the following steps: a) setting the temperature of the heat collecting constant temperature heating magnetic stirrer to the desorption temperature; b) After the desorption temperature is constant, the amine-based water-saving absorbent collaborative desorption bottle after carbon dioxide capture is placed in an oil bath, the speed of the magnetic stirrer is adjusted to a preset speed, and the timing is started; c) After desorption begins, the tail gas is first collected with a syringe, diluted and then tested with a chromatogram to confirm that the tail gas is CO2; d) Record the outlet flow rate at regular intervals. After desorption is completed, a CO2-lean liquid is obtained.

[0026] Furthermore, in step a), the desorption temperature is 373-393 K.

[0027] Furthermore, in step b), the rotation speed is 100-140 rpm.

[0028] Furthermore, in step c), the capacity of the syringe is 100 ml.

[0029] Furthermore, in step d), the desorption time is 60 to 80 min.

[0030] The beneficial effects of the present invention are: (1) The solvent effect factor δ of the present invention is a comprehensive evaluation representative index that can comprehensively reflect the component density, component concentration and other conditions of the amine-based water-reducing absorbent, and can comprehensively evaluate the carbon dioxide absorption performance of the amine-based water-reducing absorbent, including its chemical reactivity, absorption capacity, physical properties, thermal stability, regeneration ability and selectivity. The present invention has been verified by a large number of experiments and has uniquely found that when the solvent effect factor δ is in the range of 0.28 to 0.32, the chemical reaction rate of the amine-based water-reducing absorbent with carbon dioxide is high, and carbon dioxide can be quickly captured. The absorbent per unit mass or volume can absorb more carbon dioxide, and due to its low viscosity, it helps to improve the adsorption efficiency of CO2, and has strong thermal stability and regeneration ability.

[0031] 2) Strong controllability and large absorption capacity: The present invention controls the viscosity factor δ of the amine-based water-saving absorbent to 0.28~0.32, and optimizes the chemical composition and structure of the amine-based water-saving absorbent through a specific screening formula, which can increase the reaction rate and degree of reaction with CO2, thereby more effectively capturing and fixing CO2. Under optimal operating conditions, the CO2 absorption load of the amine-based water-saving absorbent can reach 2.83 mol / kg, the CO2 desorption load is 2.34 mol / kg, and the regeneration efficiency is 83.57%; after 4 absorption and desorption cycles, the desorption load of the amine-based water-saving absorbent is stabilized at more than 2.00 mol / kg each time, and the regeneration efficiency is more than 80%.

[0032] 3) Low operating energy consumption and wide adaptability: Traditional CO2 capture methods, such as liquid amine solution absorption, require a lot of water and energy to regenerate the absorbent. The low-water absorbent design reduces the amount of water used, thereby reducing the energy and cost required in the regeneration process and improving economic benefits. Low-water absorbents can be used in more application scenarios, such as coal-fired power plants, natural gas processing, industrial flue gas treatment, etc. They can adapt to different CO2 capture needs and have a wide range of application prospects.

[0033] 4) Good cycle stability and low viscosity: The auxiliary solvent added in the present invention is an organic solvent with stable chemical properties, so it does not participate in the subsequent degradation reaction. The thermochemical stability of the amine-based water-saving absorbent is strong, and the absorbent still maintains a good capture effect after multiple cycles. At the same time, the low viscosity of the amine-based water-saving absorbent not only helps to increase the diffusion rate and reaction speed of carbon dioxide, but also enhances mass transfer performance, reduces energy consumption, improves equipment performance, optimizes operating conditions, increases reaction speed, and reduces by-product generation.

[0034] 5) This invention has innovatively proposed an innovative method for constructing a solvent effect factor calculation formula, aiming to accurately screen and optimize the formula of amine low-water absorbents. This breakthrough technical path is unprecedented in the existing technical field and fully demonstrates the unique creativity and unpredictable advancement of this invention. Through the precise calculation of this formula, we can deeply analyze the influence mechanism of different low-water absorbent formulas on absorption performance, and then realize the scientific customization and optimization of absorbent formulas, opening up a new direction for the development of efficient and environmentally friendly amine absorbents. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The present invention is a schematic diagram of the process of absorbing carbon dioxide by an amine-based water-saving absorbent, wherein 1 is a carbon dioxide cylinder, 2 is a gas mass flowmeter, 3 is a bubbling absorption bottle, 4 is a heat-collecting constant temperature heating magnetic stirrer (water bath), 5 is a gas washing bottle, and 6 is a soap film flowmeter.

[0036] Figure 2 The present invention is a schematic diagram of the desorption process of the amine water-saving absorbent, wherein 7 is a heat-collecting constant temperature heating magnetic stirrer (oil bath), 8 is a bubbling absorption bottle, 9 is a straight condenser, 10 is a condensed water collection bottle, and 11 is a soap film flowmeter.

[0037] Figure 3 It is a comparison chart of carbon dioxide absorption / desorption loads of the absorbents of Example 1, Example 2, Example 3, Example 4, Comparative Example 1 and Comparative Example 2 of the present invention.

[0038] Figure 4 It is a comparison chart of the regeneration efficiency of the absorbents of Example 1, Example 2, Example 3, Example 4, Comparative Example 1 and Comparative Example 2 of the present invention.

[0039] Figure 5 This is the carbon dioxide absorption / desorption load diagram of the amine-based water-saving absorbent of Example 1 of the present invention after four cycles.

[0040] Figure 6 This is the carbon dioxide absorption / desorption load diagram of the amine-based water-saving absorbent of Example 2 of the present invention after four cycles.

[0041] Figure 7 This is the carbon dioxide absorption / desorption load diagram of the amine-based water-saving absorbent of Example 3 of the present invention after four cycles.

[0042] Figure 8 This is the carbon dioxide absorption / desorption load diagram of the amine-based water-saving absorbent of Example 4 of the present invention after 4 cycles. DETAILED DESCRIPTION

[0043] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0044] All examples and comparative examples adopt Figure 1 The device captures carbon dioxide, wherein a carbon dioxide cylinder 1, a mass flow controller MFC, a gas mass flow meter 2, a bubbling absorption bottle 3, a heat-collecting constant temperature heating magnetic stirrer 4, a gas washing bottle 5 and a soap film flow meter 6 are connected in sequence.

[0045] All examples and comparative examples adopt Figure 2 The absorbent is desorbed by a device, wherein a heat-collecting constant-temperature heating magnetic stirrer 7, a bubbling absorption bottle 8, a straight condenser tube 9, a condensed water collection bottle 10 and a soap film flowmeter 11 are connected in sequence.

[0046] Example 1 An amine low-water absorbent (abbreviated as EMH) for capturing carbon dioxide comprises, by mass percentage, 30% of the absorbent main agent EDA, 65% of the auxiliary solvent DMSO and 5% of water. The solvation effect factor of EMH is calculated by Formula 1 and Formula 2 to be 0.31.

[0047] The specific steps of EMH to capture carbon dioxide include: 1) Preparation of amine low water absorbent: Take 32.5g DMSO and 2.5g deionized water and add them to 15g EDA, stir for 1h until homogeneous, and obtain sample EMH. Measure its density and calculate its solvation effect factor based on the obtained result; 2) Check the air tightness and stability of the device: When the absorption bottle is empty, open the valve of the carbon dioxide cylinder to release CO2 with a volume concentration of 99.99% through the pressure reducing valve. Set the inlet flow rate of carbon dioxide to 120 ml / min through the mass flow controller and gas mass flow meter. Then, use the soap film flow meter to measure the outlet flow rate, which is also 120 ml / min. 3) After the flow measurement is completed, turn off the carbon dioxide inlet, turn on the heat-collecting constant temperature heating magnetic stirrer, set the speed to 120 rpm, and heat the water bath to the carbon dioxide absorption temperature of 313 K; 4) After the temperature is constant, weigh 50 g of the amine-based water-saving absorbent prepared in step 1) and place it in an absorption bottle, and then place the absorption bottle in a heat-collecting constant-temperature heating magnetic stirrer for constant temperature preheating; 5) Open the carbon dioxide inlet and pass it into the absorption bottle, start timing, take samples every 0, 5, 10, 20, 30, 40, 50 and 60 minutes, record the outlet flow of carbon dioxide each time, and observe the changes in the absorbent during the absorption process and after standing for a period of time after absorption. After the absorption is completed, a CO2 rich liquid is obtained.

[0048] After the carbon dioxide is captured, the amine-based water-saving absorbent is desorbed. The specific steps include the following: a) Set the temperature of the heat collecting constant temperature heating magnetic stirrer to the desorption temperature of 393K; b) After the desorption temperature is constant, the amine-based water-saving absorbent cooperative desorption bottle after the carbon dioxide capture is placed in an oil bath, and a magnetic particle is added to the desorption bottle; Connect one end of the straight condenser tube to the mouth of the desorption bottle through the head, and connect the other end to the soap film flowmeter; Turn on the condensing water, adjust the magnetic stirrer speed to the preset speed, and start timing; c) After desorption begins, a certain amount of tail gas is collected with a syringe, diluted and then tested with a chromatogram to determine that the substance is CO2; d) Take samples every 0, 5, 10, 20, 30, 40, 50 and 60 minutes, record the outlet flow rate each time, and observe the experimental phenomena of the absorbent during the desorption process and after standing for a period of time after desorption. After desorption is completed, CO2-lean liquid is obtained.

[0049] Depend on Figure 3 It can be seen that the CO2 absorption load of EMH is 2.83 mol / kg; the CO2 desorption load can reach 2.34 mol / kg; Figure 4 It can be seen that the regeneration efficiency of EMH is 83.57%.

[0050] Depend on Figure 5 It can be seen that in the cyclic absorption / desorption experiment of EMH, as the number of cycles increases, the absorption load and desorption load both decrease slightly, while the regeneration efficiency remains above 80%, indicating that EMH has good regeneration performance.

[0051] Example 2 An amine low-water absorbent (abbreviated as DFH) for capturing carbon dioxide comprises, by mass percentage, 35% of the main absorbent DAP, 60% of the auxiliary solvent SFL and 5% of water. The solvation effect factor of DFH is calculated by Formula 1 and Formula 2 to be 0.32.

[0052] The specific steps of DFH to capture carbon dioxide include: 1) Preparation of amine low water absorbent: Take 30g SFL and 2.5g deionized water and add them to 17.5g DAP, stir for 1h until homogeneous, and obtain sample DFH. Measure its density and calculate its solvation effect factor based on the obtained results. 2) Check the air tightness and stability of the device: When the absorption bottle is empty, open the valve of the carbon dioxide cylinder to release CO2 with a volume concentration of 99.99% through the pressure reducing valve. Set the inlet flow rate of carbon dioxide to 120 ml / min through the mass flow controller and gas mass flow meter. Then, use the soap film flow meter to measure the outlet flow rate, which is also 120 ml / min. 3) After the flow measurement is completed, turn off the carbon dioxide inlet, turn on the heat-collecting constant temperature heating magnetic stirrer, set the speed to 120 rpm, and heat the water bath to the carbon dioxide absorption temperature of 313 K; 4) After the temperature is constant, weigh 50 g of the amine-based water-saving absorbent prepared in step 1) and place it in an absorption bottle, and then place the absorption bottle in a heat-collecting constant-temperature heating magnetic stirrer for constant temperature preheating; 5) Open the carbon dioxide inlet and pass it into the absorption bottle, start timing, take samples every 0, 5, 10, 20, 30, 40, 50 and 60 minutes, record the outlet flow of carbon dioxide each time, and observe the changes in the absorbent during the absorption process and after standing for a period of time after absorption. After the absorption is completed, a CO2 rich liquid is obtained.

[0053] After the carbon dioxide is captured, the amine-based water-saving absorbent is desorbed. The specific steps include the following: a) Set the temperature of the heat collecting constant temperature heating magnetic stirrer to the desorption temperature of 393K; b) After the desorption temperature is constant, the amine-based water-saving absorbent cooperative desorption bottle after the carbon dioxide capture is placed in an oil bath, and a magnetic particle is added to the desorption bottle; Connect one end of the straight condenser tube to the mouth of the desorption bottle through the head, and connect the other end to the soap film flowmeter; Turn on the condensing water, adjust the magnetic stirring to the preset speed, and start timing; c) After desorption begins, a certain amount of tail gas is collected with a syringe, diluted and then tested with a chromatogram to determine that the substance is CO2; d) Take samples every 0, 5, 10, 20, 30, 40, 50 and 60 minutes, record the outlet flow rate each time, and observe the experimental phenomena of the absorbent during the desorption process and after standing for a period of time after desorption. After desorption is completed, CO2-lean liquid is obtained.

[0054] Depend on Figure 3 It can be seen that the CO2 absorption load of DFH is 2.78 mol / kg; the CO2 desorption load can reach 2.29 mol / kg; Depend on Figure 4It can be seen that the regeneration efficiency of DFH is 82.37%.

[0055] Depend on Figure 6 It can be seen that in the cyclic absorption / desorption experiment of DFH, as the number of cycles increases, the absorption load and desorption load both decrease slightly, while the regeneration efficiency remains above 80%, indicating that EMH has good regeneration performance.

[0056] Example 3 An amine low-water absorbent (abbreviated as EDMH) for capturing carbon dioxide comprises, by mass percentage, 25% of absorbent main agents EDA and DAP, 70% of auxiliary solvent DMSO and 5% of water. The solvation effect factor of EDMH is calculated by Formula 1 and Formula 2 to be 0.30.

[0057] The specific steps of EDMH to capture carbon dioxide include: 1) Preparation of amine low water absorbent: 35 g DMSO and 2.5 g deionized water were added to a mixture of 12.5 g EDA and DAP, and stirred for 1 h until homogeneous to obtain sample EDMH. The density of the sample was measured, and the solvation effect factor was calculated based on the obtained result. 2) Check the air tightness and stability of the device: When the absorption bottle is empty, open the valve of the carbon dioxide cylinder to release CO2 with a volume concentration of 99.99% through the pressure reducing valve. Set the inlet flow rate of carbon dioxide to 120 ml / min through the mass flow controller and gas mass flow meter. Then, use the soap film flow meter to measure the outlet flow rate, which is also 120 ml / min. 3) After the flow measurement is completed, turn off the carbon dioxide inlet, turn on the heat-collecting constant temperature heating magnetic stirrer, set the speed to 120 rpm, and heat the water bath to the carbon dioxide absorption temperature of 313 K; 4) After the temperature is constant, weigh 50 g of the amine-based water-saving absorbent prepared in step 1) and place it in an absorption bottle, and then place the absorption bottle in a heat-collecting constant-temperature heating magnetic stirrer for constant temperature preheating; 5) Open the carbon dioxide inlet and pass it into the absorption bottle, start timing, take samples every 0, 5, 10, 20, 30, 40, 50 and 60 minutes, record the outlet flow of carbon dioxide each time, and observe the changes in the absorbent during the absorption process and after standing for a period of time after absorption. After the absorption is completed, a CO2 rich liquid is obtained.

[0058] After the carbon dioxide is captured, the amine-based water-saving absorbent is desorbed. The specific steps include the following: a) Set the temperature of the heat collecting constant temperature heating magnetic stirrer to the desorption temperature of 393K; b) After the desorption temperature is constant, the amine-based water-saving absorbent cooperative desorption bottle after the carbon dioxide capture is placed in an oil bath, and a magnetic particle is added to the desorption bottle; Connect one end of the straight condenser tube to the mouth of the desorption bottle through the head, and connect the other end to the soap film flowmeter; Turn on the condensing water, adjust the magnetic stirring to the preset speed, and start timing; c) After desorption begins, a certain amount of tail gas is collected with a syringe, diluted and then tested with a chromatogram to determine that the substance is CO2; d) Take samples every 0, 5, 10, 20, 30, 40, 50 and 60 minutes, record the outlet flow rate each time, and observe the experimental phenomena of the absorbent during the desorption process and after standing for a period of time after desorption. After desorption is completed, CO2-lean liquid is obtained.

[0059] Depend on Figure 3 It can be seen that the CO2 absorption load of EDMH is 2.76 mol / kg; the CO2 desorption load can reach 2.3 mol / kg; Figure 4 It can be seen that the regeneration efficiency of EDMH is 83.33%; Depend on Figure 7 It can be seen that in the cyclic absorption / desorption experiment of EDMH, as the number of cycles increases, the absorption load and desorption load both decrease slightly, while the regeneration efficiency remains above 80%, indicating that EDMH has good regeneration performance.

[0060] Example 4 An amine-based water-reducing absorbent (abbreviated as EDMFH) for capturing carbon dioxide comprises, by mass percentage, 29% of absorbent main agents EDA and DAP, 68% of auxiliary solvents DMSO and SFL, and 3% of water. The solvation effect factor of EDMFH is calculated by Formula 1 and Formula 2 to be 0.28.

[0061] The specific steps of EDMFH to capture carbon dioxide include: 1) Preparation of amine low water absorbent: 34 g of DMSO, SFL and 1.5 g of deionized water were added to a mixture of 14.5 g of EDA and DAP, and stirred for 1 h until homogeneous to obtain a sample EDMFH. The density of the sample was measured, and the solvation effect factor was calculated based on the obtained result. 2) Check the air tightness and stability of the device: When the absorption bottle is empty, open the valve of the carbon dioxide cylinder to release CO2 with a volume concentration of 99.99% through the pressure reducing valve. Set the inlet flow rate of carbon dioxide to 120 ml / min through the mass flow controller and gas mass flow meter. Then, use the soap film flow meter to measure the outlet flow rate, which is also 120 ml / min. 3) After the flow measurement is completed, turn off the carbon dioxide inlet, turn on the heat-collecting constant temperature heating magnetic stirrer, set the speed to 120 rpm, and heat the water bath to the carbon dioxide absorption temperature of 313 K; 4) After the temperature is constant, weigh 50 g of the amine-based water-saving absorbent prepared in step 1) and place it in an absorption bottle, and then place the absorption bottle in a heat-collecting constant-temperature heating magnetic stirrer for constant temperature preheating; 5) Open the carbon dioxide inlet and pass it into the absorption bottle, start timing, take samples every 0, 5, 10, 20, 30, 40, 50 and 60 minutes, record the outlet flow of carbon dioxide each time, and observe the changes in the absorbent during the absorption process and after standing for a period of time after absorption. After the absorption is completed, a CO2 rich liquid is obtained.

[0062] After the carbon dioxide is captured, the amine-based water-saving absorbent is desorbed. The specific steps include the following: a) Set the temperature of the heat collecting constant temperature heating magnetic stirrer to the desorption temperature of 393K; b) After the desorption temperature is constant, the amine-based water-saving absorbent cooperative desorption bottle after the carbon dioxide capture is placed in an oil bath, and a magnetic particle is added to the desorption bottle; Connect one end of the straight condenser tube to the mouth of the desorption bottle through the head, and connect the other end to the soap film flowmeter; Turn on the condensing water, adjust the magnetic stirring to the preset speed, and start timing; c) After desorption begins, a certain amount of tail gas is collected with a syringe, diluted and then tested with a chromatogram to determine that the substance is CO2; d) Take samples every 0, 5, 10, 20, 30, 40, 50 and 60 minutes, record the outlet flow rate each time, and observe the experimental phenomena of the absorbent during the desorption process and after standing for a period of time after desorption. After desorption is completed, CO2-lean liquid is obtained.

[0063] Depend on Figure 3 It can be seen that the CO2 absorption load of EDMFH is 2.75 mol / kg; the CO2 desorption load can reach 2.29 mol / kg; Depend on Figure 4 It can be seen that the regeneration efficiency of EDMFH is 83.27%.

[0064] Depend on Figure 8 It can be seen that in the cyclic absorption / desorption experiment of EDMFH, as the number of cycles increases, the absorption load and desorption load both decrease slightly, while the regeneration efficiency remains above 80%, indicating that EDMH has good regeneration performance.

[0065] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the absorbent contains 40% monoethanolamine (MEA) and 60% water. The specific steps of MEA to capture carbon dioxide include: 1) Preparation of amine low water absorbent: Take 20g of single-component MEA as an organic amine absorbent and 30g of deionized water, and stir for 1h until homogeneous; 2) Check the air tightness and stability of the device: When the absorption bottle is empty, open the valve of the carbon dioxide cylinder to release CO2 with a volume concentration of 99.99% through the pressure reducing valve. Set the inlet flow rate of carbon dioxide to 120 ml / min through the mass flow controller and gas mass flow meter. Then, use the soap film flow meter to measure the outlet flow rate, which is also 120 ml / min. 3) After the flow measurement is completed, turn off the carbon dioxide inlet, turn on the heat-collecting constant temperature heating magnetic stirrer, set the speed to 120 rpm, and heat the water bath to the carbon dioxide absorption temperature of 313 K; 4) After the temperature is constant, weigh 50 g of the absorbent prepared in step 1) and place it in an absorption bottle, and then place the absorption bottle in a heat-collecting constant temperature heating magnetic stirrer for constant temperature preheating; 5) Open the carbon dioxide inlet and pass it into the absorption bottle, start timing, take samples every 0, 5, 10, 20, 30, 40, 50 and 60 minutes, record the outlet flow of carbon dioxide each time, and observe the changes in the absorbent during the absorption process and after standing for a period of time after absorption. After the absorption is completed, a CO2 rich liquid is obtained.

[0066] After the carbon dioxide is captured, the absorbent is desorbed. The specific steps include the following: a) Set the temperature of the heat collecting constant temperature heating magnetic stirrer to the desorption temperature of 393K; b) After the desorption temperature is constant, the absorbent cooperative desorption bottle after the carbon dioxide capture is placed in an oil bath, and a magnet is added to the desorption bottle; Connect one end of the straight condenser tube to the mouth of the desorption bottle through the head, and connect the other end to the soap film flowmeter; Turn on the condensing water, adjust the magnetic stirring to the preset speed, and start timing; c) After desorption begins, a certain amount of tail gas is collected with a syringe, diluted and then tested with a chromatogram to determine that the substance is CO2; d) Take samples every 0, 5, 10, 20, 30, 40, 50 and 60 minutes, record the outlet flow rate each time, and observe the experimental phenomena of the absorbent during the desorption process and after standing for a period of time after desorption. After desorption is completed, CO2-lean liquid is obtained.

[0067] Depend on Figure 3 It can be seen that the CO2 absorption load of MEA is 2.25 mol / kg; the CO2 desorption load can reach 1.25 mol / kg; Depend on Figure 4 It can be seen that the regeneration efficiency of MEA is 55.56%.

[0068] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that an amine-based water-reducing absorbent (abbreviated as NMH) for capturing carbon dioxide is used, which comprises, by mass percentage, 30% of the absorbent main agent N,N-dimethylethylenediamine, 65% of the auxiliary solvent N-methylpyrrolidone and 5% of water, and its solvation effect factor is calculated by Formula 1 and Formula 2 to be 0.25.

[0069] The specific steps for capturing carbon dioxide include: 1) Preparation of amine low water absorbent: Take 32.5g of N-methylpyrrolidone and 2.5g of deionized water and add them to a mixture of 15g of N,N-dimethylethylenediamine, stir for 1h until it becomes homogeneous, measure its density, and calculate its solvation effect factor based on the obtained result; 2) Check the air tightness and stability of the device: When the absorption bottle is empty, open the valve of the carbon dioxide cylinder to release CO2 with a volume concentration of 99.99% through the pressure reducing valve. Set the inlet flow rate of carbon dioxide to 120 ml / min through the mass flow controller and gas mass flow meter. Then, use the soap film flow meter to measure the outlet flow rate, which is also 120 ml / min. 3) After the flow measurement is completed, turn off the carbon dioxide inlet, turn on the heat-collecting constant temperature heating magnetic stirrer, set the speed to 120 rpm, and heat the water bath to the carbon dioxide absorption temperature of 313 K; 4) After the temperature is constant, weigh 50 g of the amine-based water-saving absorbent prepared in step 1) and place it in an absorption bottle, and then place the absorption bottle in a heat-collecting constant-temperature heating magnetic stirrer for constant temperature preheating; 5) Open the carbon dioxide inlet and pass it into the absorption bottle, start timing, take samples every 0, 5, 10, 20, 30, 40, 50 and 60 minutes, record the outlet flow of carbon dioxide each time, and observe the changes in the absorbent during the absorption process and after standing for a period of time after absorption. After the absorption is completed, a CO2 rich liquid is obtained.

[0070] After the carbon dioxide is captured, the amine-based water-saving absorbent is desorbed. The specific steps include the following: a) Set the temperature of the heat collecting constant temperature heating magnetic stirrer to the desorption temperature of 393K; b) After the desorption temperature is constant, the amine-based water-saving absorbent cooperative desorption bottle after the carbon dioxide capture is placed in an oil bath, and a magnetic particle is added to the desorption bottle; Connect one end of the straight condenser tube to the mouth of the desorption bottle through the head, and connect the other end to the soap film flowmeter; Turn on the condensing water, adjust the magnetic stirring to the preset speed, and start timing; c) After desorption begins, a certain amount of tail gas is collected with a syringe, diluted and then tested with a chromatogram to determine that the substance is CO2; d) Take samples every 0, 5, 10, 20, 30, 40, 50 and 60 minutes, record the outlet flow rate each time, and observe the experimental phenomena of the absorbent during the desorption process and after standing for a period of time after desorption. After desorption is completed, CO2-lean liquid is obtained.

[0071] Depend on Figure 3 It can be seen that the CO2 absorption load of NMH is 2.34 mol / kg; the CO2 desorption load can reach 1.70 mol / kg; Figure 4 It can be seen that the regeneration efficiency of NMH is 72.65%. It can be seen from the results of the above embodiments and comparative examples that the solvation effect factors of the amine-based water-saving absorbents of Examples 1 to 4 of the present invention all conform to the range of 0.28 to 0.32, and compared with the absorbents of Comparative Examples 1 and 2 whose solvation factors are not in this range, they have larger absorption capacity, higher regeneration efficiency and stronger stability.

[0072] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. An amine-based water-reducing absorbent for capturing carbon dioxide, characterized in that: In terms of mass percentage, the amine water-reducing absorbent comprises 20% to 50% of an absorbent main agent, 35% to 70% of an auxiliary solvent and 2% to 20% of water. The solvent effect factor δ of the amine water-reducing absorbent ranges from 0.28 to 0.32, and the solvent effect factor satisfies the following formulas 1 and 2: ； ； in, i It can be expressed as any one of N, M and H2O; N represents the main absorbent, N X Expressed as the xth absorbent main agent, wherein x is an integer greater than zero, and the absorbent main agent is one or a mixture of two or more; M represents auxiliary solvent, M y Expressed as the yth auxiliary solvent, wherein y is an integer greater than zero, and the auxiliary solvent is one or a mixture of two or more; Each represents the absorbent main agent N1, N2, 、N X Density, in g / L; Respectively represent the auxiliary solvents M1, M2, 、M X Density, in g / L; It is expressed as the density of water in g / L; It is expressed as the sum of the densities of all absorbent main agents, auxiliary solvents and water; The result of formula 1 is expressed in L / g, where i When N, M or H2O respectively, They are , , , wherein, based on the mass of the amine-based water-saving absorbent, is the mass percentage of the main absorbent, is the mass percentage of auxiliary solvent, is the mass percentage of water, calculated based on formula 1 , ; ρ 总 is the density of the amine-based water-saving absorbent, in g / L; δ is the solvent effect factor of the amine water-saving absorbent.

2. The amine low water absorbent according to claim 1, characterized in that: The CO2 absorption load of the amine-based water-saving absorbent is 2.70-2.90 mol / kg, the CO2 desorption load is 2.25-2.40 mol / kg, and the regeneration efficiency is 80-86%.

3. The amine low water absorbent according to claim 2, characterized in that: The chain diamine is selected from at least one of the following:

4. The amine low water absorbent according to claim 2, characterized in that: The auxiliary solvent is selected from at least one of the following:

5. An application of the amine water-saving absorbent according to any one of claims 1 to 4, characterized in that: The application comprises using the amine-based water-saving absorbent to capture carbon dioxide, including the following steps: 1) Preparation of amine low water absorbent: Dissolving the auxiliary solvent and water in the absorbent main agent and stirring until a homogeneous phase is obtained to obtain the organic amine low-water absorbent; 2) Check the air tightness and stability of the device: When the absorption bottle is empty, open the valve of the carbon dioxide cylinder to release CO2 through the pressure reducing valve, set the inlet flow rate of carbon dioxide through the mass flow controller and the gas mass flow meter, and then measure the outlet flow rate of carbon dioxide with a soap film flowmeter; 3) Turn off the carbon dioxide inlet, turn on the heat-collecting constant temperature heating magnetic stirrer, and heat the water bath to the absorption temperature of carbon dioxide; 4) After the absorption temperature is constant, weigh the amine-based water-saving absorbent and place it in the absorption bottle, and then place the absorption bottle in the heat-collecting constant-temperature heating magnetic stirrer for constant temperature heating; 5) Open the carbon dioxide inlet and pass it into the absorption bottle containing the amine-based water-saving absorbent, start timing, and record the carbon dioxide outlet flow rate every certain period of time. After the absorption is completed, a carbon dioxide-rich liquid is obtained.

6. The use according to claim 5, characterized in that: In step 2), the inlet flow rate of the carbon dioxide is set to 100-140 mL / min.

7. The use according to claim 6, characterized in that: In step 3), the absorption temperature is 303~323K.

8. The use according to claim 5, characterized in that: The application further comprises desorbing the amine-based water-saving absorbent after the carbon dioxide is captured, including the following steps: a) setting the temperature of the heat collecting constant temperature heating magnetic stirrer to the desorption temperature; b) After the desorption temperature is constant, the amine-based water-saving absorbent collaborative desorption bottle after carbon dioxide capture is placed in an oil bath, the speed of the magnetic stirrer is adjusted to a preset speed, and the timing is started; c) After desorption begins, the tail gas is first collected with a syringe, diluted and then tested with a chromatogram to confirm that the tail gas is CO2; d) Record the outlet flow rate at regular intervals. After desorption is completed, a CO2-lean liquid is obtained.

9. The use according to claim 8, characterized in that: In step a), the desorption temperature is 373-393 K.

10. The use according to claim 9, characterized in that: In step d), the desorption time is 60 to 80 min.

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