Liquid-liquid two-phase carbon dioxide absorbent as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of carbon dioxide absorbents, and particularly relates to a liquid-liquid two-phase carbon dioxide absorbent as well as a preparation method and application thereof. The liquid-liquid two-phase carbon dioxide absorbent provided by the invention comprises micromolecular monoamine, a tertiary amine phase-splitting agent, an antioxidant, a water-soluble organic solvent, water and the like, the micromolecular monoamine in the composition is responsible for chemical reaction with carbon dioxide, and the tertiary amine phase-splitting agent can promote phase separation and reaction rate; meanwhile, due to the added antioxidant, the circulation capacity is improved, in addition, the use of water is reduced, and the latent heat is reduced, so that the carbon dioxide absorbent provided by the invention has excellent absorption rate, absorption capacity and circulation capacity, and meanwhile, the energy consumption can be reduced, and the viscosity is low; therefore, the technical problem of low performance of the carbon dioxide absorbent in the prior art is solved.

Description

Technical Field

[0001] The present application belongs to the technical field of carbon dioxide absorbents, and in particular relates to a liquid-liquid two-phase carbon dioxide absorbent and a preparation method and application thereof. Background Art

[0002] Anthropogenic carbon emissions caused by social development since the Industrial Revolution have caused a rapid increase in the concentration of carbon dioxide in the atmosphere, resulting in global warming and intensifying the greenhouse effect. In order to solve the dilemma of social development and environmental protection, carbon capture and storage (CCS) can reduce the amount of carbon dioxide emitted into the atmosphere and has attracted the attention of scientists, technicians and environmentalists around the world.

[0003] In addition to physical treatment methods such as molecular sieves and semipermeable membranes, chemical absorption, as a mature carbon dioxide capture technology, occupies a dominant position in industrial applications. It is particularly suitable for treating post-combustion flue gas with low carbon dioxide concentrations, and exhibits excellent removal effects and large absorption capacity. However, traditional amine absorbents, such as carbon capture and storage systems based on 30 wt.% monoethanolamine (MEA), have high energy consumption in the regeneration process (approximately 3.4-3.7 GJ / t CO2) and require an external heat source, resulting in this energy consumption accounting for 60-80% of the total energy consumption of the carbon dioxide absorption process, limiting its further improvement in energy efficiency. Therefore, the development of highly efficient and energy-saving absorbents is of great significance for reducing regeneration energy consumption and promoting the development of chemical absorption technology.

[0004] In the exploration of strategies to reduce energy consumption in the process of capturing carbon dioxide by chemical absorption, the concept of low-water carbon dioxide absorbent has received increasing attention. This strategy to reduce energy consumption uses a stable organic solvent with low specific heat capacity to replace water. As the water content decreases, the latent heat is also significantly reduced, effectively reducing the energy consumption of the regeneration process. Organic amines, ionic liquids and amino silicone oils are considered as the main active ingredients of low-water carbon dioxide absorbents to react with carbon dioxide. However, when ionic liquids and amino silicone oils are used in low-water carbon dioxide absorbents, they face challenges of high viscosity and cost. High-viscosity low-water carbon dioxide absorbents have poor flow properties and require more energy for stirring, transportation and regeneration, affecting mass transfer efficiency. For example, the GAP-0 ionic liquid absorbent proposed by Perry's research group has a viscosity of up to 1300mPa·s at 40°C. At the same time, the two-phase absorbent of polyamines in organic amines also has the problem of high rich-phase viscosity, which limits its development in actual industry. In contrast, low-water carbon dioxide absorbents with small molecule monoamines as the main component are considered to have the potential to break through the "high viscosity barrier" due to their lower viscosity.

[0005] However, the carbon dioxide absorbent used in the chemical absorption method has requirements for performance in terms of fast carbon dioxide absorption rate, absorption capacity, circulation capacity, etc. in addition to viscosity and energy consumption. The current carbon dioxide absorbent has low performance and is difficult to meet the requirements. Summary of the invention

[0006] In view of this, the present application provides a liquid-liquid two-phase carbon dioxide absorbent and a preparation method and application thereof, which are used to solve the technical problem of low performance of carbon dioxide absorbent in the prior art.

[0007] In a first aspect, the present application provides a liquid-liquid two-phase carbon dioxide absorbent, the components of which include: a small molecule monoamine, a tertiary amine phase separator, an antioxidant, a water-soluble organic solvent and water.

[0008] Preferably, the small molecule monoamine is selected from at least one of ethanolamine, N-ethylethanolamine, 2-(methylamino)ethanol and isopropanolamine.

[0009] More preferably, the small molecule monoamine is selected from N-ethylethanolamine and / or 2-(methylamino)ethanol.

[0010] Preferably, the tertiary amine phase separator is selected from at least one of N,N,N,N-tetramethylethylenediamine, N,N,N',N'-tetramethyl-1,3-propylenediamine, N,N-dimethylbutylamine, triethylamine, N,N-diethylpropylamine, N,N-diethylbutylamine, N,N,N',N'',N''-pentamethyldivinyltriamine, N,N-dimethylcyclohexylamine, 1-methylpiperidine, 1-ethylpiperidine, N,N-diethylcyclohexylamine and 1,4-diethylpiperazine.

[0011] More preferably, the tertiary amine phase separation agent is selected from 1-methylpiperidine.

[0012] Preferably, the antioxidant is selected from butylated hydroxyanisole.

[0013] Preferably, the water-soluble organic solvent is selected from at least one of N,N-dimethylpropionamide, dimethyl sulfoxide, N-methylpyrrolidone, sulfolane, dimethyl sulfoxide, N,N-dimethylacetamide, N,N-dimethylformamide and N,N-dimethylpropionamide.

[0014] More preferably, the water-soluble organic solvent is selected from N,N-dimethylpropionamide.

[0015] Preferably, calculated in parts by mass, the low-viscosity liquid-liquid two-phase water-less carbon dioxide absorbent includes: 1000-2000 parts by mass of a small molecule monoamine, 1000-2000 parts by mass of a tertiary amine phase separator, 0.5-2 parts by mass of an antioxidant, 1250-2250 parts by mass of a water-soluble organic solvent and 100-500 parts by mass of water.

[0016] The second aspect of the present application provides a method for preparing the liquid-liquid two-phase carbon dioxide absorbent described in the first aspect of the present application, which can prepare a liquid-liquid two-phase carbon dioxide absorbent described in the first aspect, comprising the steps of: uniformly mixing a small molecule monoamine, a tertiary amine phase separator, an antioxidant, a water-soluble organic solvent and water to obtain a liquid-liquid two-phase carbon dioxide absorbent.

[0017] The third aspect of the present application provides the use of the liquid-liquid two-phase carbon dioxide absorbent described in the first aspect in capturing carbon dioxide gas in exhaust gas.

[0018] Preferably, the waste gas is flue gas generated by coal combustion in a coal-fired power plant. Preferably, the application of the liquid-liquid two-phase carbon dioxide absorbent in capturing carbon dioxide gas in waste gas is specifically: heating the liquid-liquid two-phase carbon dioxide absorbent to 35°C to 55°C to absorb carbon dioxide.

[0019] More preferably, the liquid-liquid two-phase carbon dioxide absorbent is heated to 40° C. to 50° C. to absorb carbon dioxide.

[0020] Furthermore, the liquid-liquid two-phase carbon dioxide absorbent can be heated to 70° C. to 110° C. to desorb carbon dioxide.

[0021] More preferably, the liquid-liquid two-phase carbon dioxide absorbent is heated to 80° C. to 100° C. to desorb carbon dioxide.

[0022] Compared with the prior art, the present application provides a liquid-liquid two-phase carbon dioxide absorbent having at least the following beneficial effects:

[0023] 1. The liquid-liquid two-phase carbon dioxide absorbent provided in the present application can improve the absorption capacity and energy consumption of the carbon dioxide absorbent; after absorbing for 2 hours under the reaction conditions of 40°C and 12 kPa CO2 partial pressure, the maximum absorption load is around 0.64 mol / mol, while the maximum carbon dioxide absorption load of the conventional 30wt% monoethanolamine (MEA) aqueous carbon dioxide absorbent is 0.461 mol / mol, which is 28% higher; at the same time, under the desorption conditions at 90°C, the circulation load is 0.62 mol / mol, while the circulation capacity of the conventional 30wt% monoethanolamine (MEA) aqueous carbon dioxide absorbent is around 0.30 mol / mol, which is 110% higher; in addition, the regeneration energy consumption of the carbon dioxide absorbent provided in the present application is 2.4 GJ / t CO2, while the energy consumption of the conventional 30wt% monoethanolamine (MEA) aqueous carbon dioxide absorbent is around 3.25 GJ / t CO2, which is 36.8% lower.

[0024] 2. The liquid-liquid two-phase carbon dioxide absorbent provided in the present application can increase the cycle load of the carbon dioxide absorbent. After 10 cycles of absorption / desorption tests, 98% of the cycle load can still be retained.

[0025] 3. The liquid-liquid two-phase carbon dioxide absorbent provided in the present application can increase the carbon dioxide absorption load, reduce the volume of the CO2-rich phase and reduce the viscosity by selecting the types of small molecule monoamines, tertiary amine phase separators and organic solvents. DETAILED DESCRIPTION

[0026] The present application provides a liquid-liquid two-phase carbon dioxide absorbent and a preparation method and application thereof, which are used to solve the technical problem that the performance of carbon dioxide absorbent in the prior art is not high.

[0027] The technical solution of the present application will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0028] In view of the defect that the carbon dioxide absorbent used in the current chemical absorption method has low performance, the present application provides a liquid-liquid two-phase carbon dioxide absorbent, which comprises a small molecule monoamine, a tertiary amine phase separator, an antioxidant, a water-soluble organic solvent and water; wherein the small molecule monoamine is the main active component responsible for chemically reacting with carbon dioxide to achieve effective capture of carbon dioxide, the tertiary amine phase separator promotes phase separation and reaction rate, and the antioxidant can reduce the oxidative degradation of the absorbent, improve the recycling rate of the absorbent, and reduce the decrease in the circulation capacity. At the same time, the water-soluble organic solvent reduces the viscosity and increases the solubility of carbon dioxide, reduces the amount of water used, and reduces the latent heat of vaporization, thereby reducing the regeneration energy consumption and operating cost of the carbon dioxide absorbent. As a result, the carbon dioxide absorbent provided by the present application can reduce energy consumption, have low viscosity, and a small rich phase volume. It also has excellent absorption rate, absorption capacity and circulation capacity, and is an efficient and energy-saving low-viscosity liquid-liquid two-phase low-water carbon dioxide absorbent, thereby overcoming the defect that the carbon dioxide absorbent used in the current chemical absorption method has low performance and is difficult to meet the requirements.

[0029] Coal-fired power plants convert the heat energy of coal combustion into electrical energy. The main component of coal is carbon. The gas component in the flue gas generated by coal combustion is mainly carbon dioxide. At the same time, coal contains a small amount of sulfur, so the gas component of the flue gas after coal combustion contains a small amount of sulfur dioxide; and the particulate matter components in the flue gas are mainly a small amount of unburned carbon particles, ash and other components; therefore, the liquid-liquid two-phase carbon dioxide absorbent provided in the present application can capture the carbon dioxide gas component in the flue gas generated by coal combustion in coal-fired power plants.

[0030] Preferably, the present application also improves the types of components in the liquid-liquid two-phase carbon dioxide absorbent; wherein the small molecule monoamine is selected from at least one of ethanolamine (MEA), N-ethylethanolamine (EAE), 2-(methylamino)ethanol (MAE), and isopropanolamine (IPA); wherein, when the small molecule monoamine is selected from N-ethylethanolamine or 2-(methylamino)ethanol, due to the presence of secondary amine structures in the molecules of the two, compared with ethanolamine, the absorption capacity is higher and the reaction heat is reduced, thereby increasing the maximum absorption load. Compounding N-ethylethanolamine and 2-(methylamino)ethanol and adding them to the carbon dioxide absorbent can further increase the maximum absorption load. The relevant information of the selectable small molecule monoamines is shown in Table 1.

[0031] Table 1: Small molecule monoamines

[0032]

[0033] Preferably, the present application also improves the tertiary amine phase separator in the liquid-liquid two-phase carbon dioxide absorbent; the tertiary amine phase separator can be selected from N,N,N,N-tetramethylethylenediamine (TMEDA), N,N,N',N'-tetramethyl-1,3-propylenediamine (TMPDA), N,N-dimethylbutylamine (DMBA), triethylamine (Et3N), N,N-diethylpropylamine (DEPA), N,N-diethylbutylamine (DEBA), N,N,N',N'',N ''-pentamethyldiethylenetriamine (PMDETA), N,N-dimethylcyclohexylamine (DMCA), 1-methylpiperidine (MPD), 1-ethylpiperidine (EPD), N,N-diethylcyclohexylamine (DECA), 1,4-diethylpiperazine (DEPZ) and other ingredients; among them, when the tertiary amine phase separator is selected from 1-methylpiperidine, the rich phase volume can be further reduced and the performance and efficiency of the carbon dioxide absorbent can be improved; the relevant information of the selectable tertiary amine phase separator is shown in Table 2.

[0034] Table 2: Tertiary amine phase separation agents

[0035]

[0036] Preferably, the present application also improves the antioxidant in the liquid-liquid two-phase carbon dioxide absorbent; when the antioxidant is selected from butylated hydroxyanisole, the circulation capacity of the carbon dioxide absorbent can be greatly improved.

[0037] Preferably, the present application also improves the water-soluble organic solvent in the liquid-liquid two-phase carbon dioxide absorbent; the water-soluble organic solvent can be selected from N-methylpyrrolidone (NMP), cyclopentane sulfone (SFL), dimethyl sulfoxide (DMSO), N,N-dimethylacetamide (DMAC), N,N-dimethylformamide (DMF), N,N-dimethylpropionamide (DMPA); when the water-soluble organic solvent is selected from N,N-dimethylpropionamide, it can effectively reduce the viscosity of the carbon dioxide absorbent, improve the regeneration energy consumption and operating cost of the absorbent; the relevant information of the selectable water-soluble organic solvent is shown in Table 3.

[0038] Table 3: Water-soluble organic solvents

[0039]

[0040] Preferably, the low-viscosity liquid-liquid two-phase low-water carbon dioxide absorbent provided in the present application includes, by mass, 1000-2000 parts by mass of small molecule monoamine, 1000-2000 parts by mass of tertiary amine phase separator, 0.5-2 parts by mass of antioxidant, 1250-2250 parts by mass of water-soluble organic solvent and 100-500 parts by mass of water; at this ratio, the carbon dioxide absorbent can have the characteristic of "low water" and still keep the carbon dioxide absorbent solution uniform and stable.

[0041] Correspondingly, the present application also provides a method for preparing a low-viscosity liquid-liquid two-phase low-water carbon dioxide absorbent, which can be obtained by uniformly mixing a small molecule monoamine, a tertiary amine phase separator, an antioxidant, a water-soluble organic solvent and water.

[0042] Correspondingly, the present application also provides the application of the above-mentioned liquid-liquid two-phase carbon dioxide absorbent in capturing carbon dioxide-containing gas; the application object is specifically the application in capturing carbon dioxide-containing flue gas generated by coal combustion in coal-fired power plants, and the application process is specifically absorbing carbon dioxide at 35°C~55°C and desorbing carbon dioxide at 70°C~110°C.

[0043] Example 1

[0044] Example 1 of the present application provides a liquid-liquid two-phase carbon dioxide absorbent, including a preparation process and a performance testing process.

[0045] The preparation process of the liquid-liquid two-phase carbon dioxide absorbent includes: mixing 8g N-ethylethanolamine, 4g 2-(methylamino)ethanol, 12g 1-methylpiperidine, 14g N,N-dimethylpropionamide, 2g deionized water and 0.008g butylated hydroxyanisole in a beaker to obtain a liquid-liquid two-phase carbon dioxide absorbent with a uniform and stable solution.

[0046] The performance test process of the liquid-liquid two-phase carbon dioxide absorbent includes: pouring the liquid-liquid two-phase carbon dioxide absorbent into a three-necked flask and placing it in a water bath, the water bath temperature is stabilized at 40°C, and passing a simulated flue gas composed of 12% carbon dioxide and 88% nitrogen into the absorption bottle at a flow rate of 500ml / min, and reacting for 2 hours; after the reaction, the saturated absorbent is taken out and its phase separation performance is observed. The results show that the volume ratio of the CO2-rich phase is 72%, and the volume ratio of the CO2-lean phase is 28%.

[0047] Example 2

[0048] Example 2 of the present application provides a liquid-liquid two-phase carbon dioxide absorbent, including a preparation process and a performance testing process.

[0049] The preparation process of the liquid-liquid two-phase carbon dioxide absorbent includes: mixing 8g N-ethylethanolamine, 4g 2-(methylamino)ethanol, 12g 1-methylpiperidine, 14g N,N-dimethylpropionamide, 2g deionized water and 0.008g butylated hydroxyanisole in a beaker to obtain a liquid-liquid two-phase carbon dioxide absorbent with a uniform and stable solution.

[0050] The performance test process of the liquid-liquid two-phase carbon dioxide absorbent includes: pouring the liquid-liquid two-phase carbon dioxide absorbent into a three-necked flask and placing it in a water bath, the water bath temperature is stabilized at 40°C, and passing a simulated flue gas composed of 12% carbon dioxide and 88% nitrogen into the absorption bottle at a flow rate of 500ml / min, and reacting for 2 hours; during the reaction, an online infrared analyzer is used to measure the CO2 concentration at the outlet of the reaction system and calculate the maximum absorption load to be 0.64mol / mol. After 10 cycles of absorption / desorption tests, its circulation capacity is 0.615mol / mol, which is reduced by about 4%.

[0051] Example 3

[0052] Example 3 of the present application provides a liquid-liquid two-phase carbon dioxide absorbent, including a preparation process and a performance testing process.

[0053] The preparation process of the liquid-liquid two-phase carbon dioxide absorbent includes: mixing 8g N-ethylethanolamine, 4g 2-(methylamino)ethanol, 12g 1-methylpiperidine, 14g N,N-dimethylpropionamide, 2g deionized water and 0.008g butylated hydroxyanisole in a beaker to obtain a liquid-liquid two-phase carbon dioxide absorbent with a uniform and stable solution.

[0054] The performance test process of the liquid-liquid two-phase carbon dioxide absorbent includes: pouring the liquid-liquid two-phase carbon dioxide absorbent into a three-necked flask and placing it in a water bath, the water bath temperature is stabilized at 40°C, and a simulated flue gas composed of 12% carbon dioxide and 88% nitrogen is passed into the absorption bottle at a flow rate of 500ml / min, and reacted for 2 hours; then a desorption experiment is carried out at 90°C. During the reaction, an online infrared analyzer is used to measure the CO2 concentration at the outlet of the reaction system and the circulation load is calculated to be 0.62mol / mol.

[0055] Example 4

[0056] Example 4 of the present application provides a liquid-liquid two-phase carbon dioxide absorbent, including a preparation process and a performance testing process.

[0057] The preparation process of the liquid-liquid two-phase carbon dioxide absorbent includes: mixing 8g N-ethylethanolamine, 4g 2-(methylamino)ethanol, 12g 1-methylpiperidine, 14g N,N-dimethylpropionamide, 2g deionized water and 0.008g butylated hydroxyanisole in a beaker to obtain a liquid-liquid two-phase carbon dioxide absorbent with a uniform and stable solution, and the tested viscosity is 1.17 mPa·s (40°C).

[0058] The performance test process of the liquid-liquid two-phase carbon dioxide absorbent includes: pouring the liquid-liquid two-phase carbon dioxide absorbent into a three-necked flask and placing it in a water bath, the water bath temperature is stabilized at 40°C, and a simulated flue gas composed of 12% carbon dioxide and 88% nitrogen is passed into the absorption bottle at a flow rate of 500ml / min, and reacted for 2 hours; then the viscosity of the CO2-rich phase is measured at 40°C to be 11.68mPa·s.

[0059] Example 5

[0060] Example 5 of the present application provides a liquid-liquid two-phase carbon dioxide absorbent, including a preparation process and a performance testing process.

[0061] The preparation process of the liquid-liquid two-phase carbon dioxide absorbent includes: mixing 8g N-ethylethanolamine, 4g 2-(methylamino)ethanol, 12g 1-methylpiperidine, 14g N,N-dimethylpropionamide, 2g deionized water and 0.008g butylated hydroxyanisole in a beaker to obtain a liquid-liquid two-phase carbon dioxide absorbent with a uniform and stable solution.

[0062] The performance test process of the liquid-liquid two-phase carbon dioxide absorbent includes: pouring the liquid-liquid two-phase carbon dioxide absorbent into a gas-liquid phase equilibrium reactor to test their reaction heat, and calculating the regeneration energy consumption of the carbon dioxide absorbent according to the Antony equation to be 2.4GJ / t CO2.

[0063] Example 6

[0064] Example 6 of the present application provides a liquid-liquid two-phase carbon dioxide absorbent, using N-ethylethanolamine as a small molecule monoamine, including a preparation process and a performance testing process.

[0065] The preparation process of the liquid-liquid two-phase carbon dioxide absorbent includes: mixing 12g N-ethylethanolamine, 12g 1-methylpiperidine, 14g N,N-dimethylpropionamide, 2g deionized water and 0.008g butylated hydroxyanisole in a beaker to obtain a liquid-liquid two-phase carbon dioxide absorbent with a uniform and stable solution.

[0066] The performance test process of the liquid-liquid two-phase carbon dioxide absorbent includes: pouring the liquid-liquid two-phase carbon dioxide absorbent into a three-necked flask and placing it in a water bath, the water bath temperature is stabilized at 40°C, and passing a simulated flue gas composed of 12% carbon dioxide and 88% nitrogen into the absorption bottle at a flow rate of 500ml / min, and reacting for 2 hours; during the reaction, an online infrared analyzer is used to measure the CO2 concentration at the outlet of the reaction system and calculate the maximum absorption load to be 0.62mol / mol.

[0067] Example 7

[0068] Example 7 of the present application provides a liquid-liquid two-phase carbon dioxide absorbent, using 2-(methylamino)ethanol as a small molecule monoamine, including a preparation process and a performance testing process.

[0069] The preparation process of the liquid-liquid two-phase carbon dioxide absorbent includes: mixing 12g of 2-(methylamino)ethanol, 12g of 1-methylpiperidine, 14g of N,N-dimethylpropionamide, 2g of deionized water and 0.008g of butylated hydroxyanisole in a beaker to obtain a liquid-liquid two-phase carbon dioxide absorbent with a uniform and stable solution.

[0070] The performance test process of the liquid-liquid two-phase carbon dioxide absorbent includes: pouring the liquid-liquid two-phase carbon dioxide absorbent into a three-necked flask and placing it in a water bath, the water bath temperature is stabilized at 40°C, and passing a simulated flue gas composed of 12% carbon dioxide and 88% nitrogen into the absorption bottle at a flow rate of 500ml / min, and reacting for 2 hours; during the reaction, an online infrared analyzer is used to measure the CO2 concentration at the outlet of the reaction system and calculate the maximum absorption load to be 0.53mol / mol.

[0071] Example 8

[0072] Example 8 of the present application provides a low-viscosity liquid-liquid two-phase carbon dioxide absorbent, using N,N,N,N-tetramethylethylenediamine as a phase separation agent, including a preparation process and a performance testing process.

[0073] The preparation process of the liquid-liquid two-phase carbon dioxide absorbent includes: mixing 8g N-ethylethanolamine, 4g 2-(methylamino)ethanol, 12g N,N,N,N-tetramethylethylenediamine, 14g N,N-dimethylpropionamide, 2g deionized water and 0.008g butylated hydroxyanisole in a beaker to obtain a liquid-liquid two-phase carbon dioxide absorbent with a uniform and stable solution.

[0074] The performance test process of the liquid-liquid two-phase carbon dioxide absorbent includes: pouring the liquid-liquid two-phase carbon dioxide absorbent into a three-necked flask and placing it in a water bath, the water bath temperature is stabilized at 40°C, and passing a simulated flue gas composed of 12% carbon dioxide and 88% nitrogen into the absorption bottle at a flow rate of 500ml / min, and reacting for 2 hours; after the reaction, the saturated absorbent is taken out and its phase separation performance is observed. The results show that the volume ratio of the CO2-rich phase is 74%, and the volume ratio of the CO2-lean phase is 26%.

[0075] Example 9

[0076] Example 9 of the present application provides a liquid-liquid two-phase carbon dioxide absorbent, using N-methylpyrrolidone as an organic solvent, including a preparation process and a performance testing process.

[0077] The preparation process of the liquid-liquid two-phase carbon dioxide absorbent includes: mixing 8g N-ethylethanolamine, 4g 2-(methylamino)ethanol, 12g 1-methylpiperidine, 14g N-methylpyrrolidone, 2g deionized water and 0.008g butylated hydroxyanisole in a beaker to obtain a liquid-liquid two-phase carbon dioxide absorbent with a uniform and stable solution.

[0078] The performance test process of the liquid-liquid two-phase carbon dioxide absorbent includes: pouring the liquid-liquid two-phase carbon dioxide absorbent into a three-necked flask and placing it in a water bath, the water bath temperature is stabilized at 40°C, and a simulated flue gas composed of 12% carbon dioxide and 88% nitrogen is passed into the absorption bottle at a flow rate of 500ml / min, and reacted for 2 hours; then the viscosity of the CO2-rich phase is measured at 40°C to be 78.76mPa·s.

[0079] Example 10

[0080] Example 10 of the present application provides a liquid-liquid two-phase carbon dioxide absorbent without the addition of butylated hydroxyanisole, including a preparation process and a performance testing process.

[0081] The preparation process of the liquid-liquid two-phase carbon dioxide absorbent includes: mixing 8g N-ethylethanolamine, 4g 2-(methylamino)ethanol, 12g 1-methylpiperidine, 14g N,N-dimethylpropionamide and 2g deionized water in a beaker to obtain a liquid-liquid two-phase carbon dioxide absorbent with a uniform and stable solution.

[0082] The performance test process of the liquid-liquid two-phase carbon dioxide absorbent includes: pouring the liquid-liquid two-phase carbon dioxide absorbent into a three-necked flask and placing it in a water bath, the water bath temperature is stabilized at 40°C, and passing a simulated flue gas composed of 12% carbon dioxide and 88% nitrogen into the absorption bottle at a flow rate of 500ml / min, and reacting for 2 hours; during the reaction, an online infrared analyzer is used to measure the CO2 concentration at the outlet of the reaction system and calculate the maximum absorption load to be 0.64mol / mol, and after 10 cycles of absorption / desorption tests, its circulation capacity is 0.525mol / mol, which is reduced by about 18%.

[0083] Embodiment 11

[0084] Example 11 of the present application provides a liquid-liquid two-phase carbon dioxide absorbent, which adjusts the temperature during carbon dioxide absorption, including a preparation process and a performance testing process.

[0085] The preparation process of the liquid-liquid two-phase carbon dioxide absorbent includes: mixing 8g N-ethylethanolamine, 4g 2-(methylamino)ethanol, 12g 1-methylpiperidine, 14g N,N-dimethylpropionamide, 2g deionized water and 0.008g butylated hydroxyanisole in a beaker to obtain a liquid-liquid two-phase carbon dioxide absorbent with a uniform and stable solution.

[0086] The performance test process of the liquid-liquid two-phase carbon dioxide absorbent includes: pouring the liquid-liquid two-phase carbon dioxide absorbent into a three-necked flask and placing it in a water bath, the water bath temperature is stabilized at 50°C, and passing a simulated flue gas composed of 12% carbon dioxide and 88% nitrogen into the absorption bottle at a flow rate of 500ml / min. The reaction takes 2 hours, and during the reaction, an online infrared analyzer is used to measure the CO2 concentration at the outlet of the reaction system and the circulating load is calculated to be 0.55mol / mol.

[0087] Example 12

[0088] Example 12 of the present application provides a liquid-liquid two-phase carbon dioxide absorbent, which adjusts the temperature when desorbing carbon dioxide, including a preparation process and a performance testing process.

[0089] The preparation process of the liquid-liquid two-phase carbon dioxide absorbent includes: mixing 8g N-ethylethanolamine, 4g 2-(methylamino)ethanol, 12g 1-methylpiperidine, 14g N,N-dimethylpropionamide, 2g deionized water and 0.008g butylated hydroxyanisole in a beaker to obtain a liquid-liquid two-phase carbon dioxide absorbent with a uniform and stable solution.

[0090] The performance test process of the liquid-liquid two-phase carbon dioxide absorbent includes: pouring the liquid-liquid two-phase carbon dioxide absorbent into a three-necked flask and placing it in a water bath, the water bath temperature is stabilized at 40°C, and a simulated flue gas composed of 12% carbon dioxide and 88% nitrogen is passed into the absorption bottle at a flow rate of 500ml / min, and reacted for 2 hours; then a desorption experiment is carried out at 80°C. During the reaction, an online infrared analyzer is used to measure the CO2 concentration at the outlet of the reaction system and the circulation load is calculated to be 0.50mol / mol.

[0091] Example 13

[0092] Example 13 of the present application provides a liquid-liquid two-phase carbon dioxide absorbent, which adjusts the temperature when desorbing carbon dioxide, including a preparation process and a performance testing process.

[0093] The preparation process of the liquid-liquid two-phase carbon dioxide absorbent includes: mixing 8g N-ethylethanolamine, 4g 2-(methylamino)ethanol, 12g 1-methylpiperidine, 14g N,N-dimethylpropionamide, 2g deionized water and 0.008g butylated hydroxyanisole in a beaker to obtain a liquid-liquid two-phase carbon dioxide absorbent with a uniform and stable solution.

[0094] The performance test process of the liquid-liquid two-phase carbon dioxide absorbent includes: pouring the liquid-liquid two-phase carbon dioxide absorbent into a three-necked flask and placing it in a water bath, the water bath temperature is stabilized at 40°C, and a simulated flue gas composed of 12% carbon dioxide and 88% nitrogen is passed into the absorption bottle at a flow rate of 500ml / min, and reacted for 2 hours; then a desorption experiment is carried out at 100°C. During the reaction, an online infrared analyzer is used to measure the CO2 concentration at the outlet of the reaction system and the circulation load is calculated to be 0.64mol / mol.

[0095] Embodiment 14

[0096] Example 14 of the present application provides a liquid-liquid two-phase carbon dioxide absorbent, in which the dosage of small molecule monoamine is adjusted, including a preparation process and a performance testing process.

[0097] The preparation process of the liquid-liquid two-phase carbon dioxide absorbent includes: mixing 6g N-ethylethanolamine, 4g 2-(methylamino)ethanol, 12g 1-methylpiperidine, 14g N,N-dimethylpropionamide, 4g deionized water and 0.008g butylated hydroxyanisole in a beaker to obtain a liquid-liquid two-phase carbon dioxide absorbent with a uniform and stable solution.

[0098] The performance test process of the liquid-liquid two-phase carbon dioxide absorbent includes: pouring the liquid-liquid two-phase carbon dioxide absorbent into a three-necked flask and placing it in a water bath, the water bath temperature is stabilized at 40°C, and a simulated flue gas composed of 12% carbon dioxide and 88% nitrogen is passed into the absorption bottle at a flow rate of 500ml / min, and reacted for 2 hours; during the reaction, an online infrared analyzer is used to measure the CO2 concentration at the outlet of the reaction system and the maximum absorption load is calculated to be 0.65mol / mol; then a desorption experiment is carried out at 90°C, and during the reaction, an online infrared analyzer is used to measure the CO2 concentration at the outlet of the reaction system and the circulation load is calculated to be 0.60mol / mol; then the viscosity of the CO2-rich phase is measured at 40°C to be 10.72mPa·s.

[0099] Embodiment 15

[0100] Example 15 of the present application provides a liquid-liquid two-phase carbon dioxide absorbent, in which the dosage of the tertiary amine phase separator is adjusted, including a preparation process and a performance testing process.

[0101] The preparation process of the liquid-liquid two-phase carbon dioxide absorbent includes: mixing 8g N-ethylethanolamine, 4g 2-(methylamino)ethanol, 20g 1-methylpiperidine, 6g N,N-dimethylpropionamide, 4g deionized water and 0.008g butylated hydroxyanisole in a beaker to obtain a liquid-liquid two-phase carbon dioxide absorbent with a uniform and stable solution.

[0102] The performance test process of the liquid-liquid two-phase carbon dioxide absorbent includes: pouring the liquid-liquid two-phase carbon dioxide absorbent into a three-necked flask and placing it in a water bath, the water bath temperature is stabilized at 40°C, and a simulated flue gas composed of 12% carbon dioxide and 88% nitrogen is passed into the absorption bottle at a flow rate of 500ml / min, and reacted for 2 hours; during the reaction, an online infrared analyzer is used to measure the CO2 concentration at the outlet of the reaction system and the maximum absorption load is calculated to be 0.62mol / mol; then a desorption experiment is carried out at 90°C, and during the reaction, an online infrared analyzer is used to measure the CO2 concentration at the outlet of the reaction system and the circulation load is calculated to be 0.60mol / mol; then the viscosity of the CO2-rich phase is measured at 40°C to be 13.88mPa·s.

[0103] By comparing Examples 2, 6 and 7 of the present application, it can be seen that different small molecule monoamines will affect the maximum absorption load of the carbon dioxide absorbent. When N-ethylethanolamine and 12g of 2-(methylamino)ethanol are selected as small molecule monoamines and added to the carbon dioxide absorbent, the maximum absorption load of the carbon dioxide absorbent will be increased.

[0104] By comparing Examples 1 and 8 of the present application, it can be seen that different tertiary amine phase separators will affect the rich phase volume of the carbon dioxide absorbent. When 1-methylpiperidine is selected as the tertiary amine phase separator and added to the carbon dioxide absorbent, the volume of the CO2-rich phase in the saturated absorbent will be reduced.

[0105] By comparing Examples 4 and 9 of the present application, it can be seen that different organic solvents, such as N-methylpyrrolidone, will affect the viscosity of the CO2-rich phase in the carbon dioxide absorbent. When N,N-dimethylpropionamide is selected as the organic solvent and added to the carbon dioxide absorbent, the viscosity of the CO2-rich phase in the saturated absorbent will be reduced.

[0106] By comparing Examples 2 and 10 of the present application, it can be seen that the addition reduces the oxidative degradation of the carbon dioxide absorbent, so that the circulation capacity of the carbon dioxide absorbent decreases less, thereby improving the recycling rate of the carbon dioxide absorbent.

[0107] At the same time, by comparing Examples 1-5 and Examples 11-15, it can be seen that by adjusting the amount of raw materials such as small molecular monoamines, tertiary amine phase separators, etc. in the carbon dioxide absorber, and the temperature of absorbing and desorbing carbon dioxide, the performance of the carbon dioxide absorber can be further improved.

[0108] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A liquid-liquid two-phase carbon dioxide absorbent, characterized in that: include: Small molecule monoamine, tertiary amine phase separation agent, antioxidant, water-soluble organic solvent and water.

2. A liquid-liquid two-phase carbon dioxide absorbent according to claim 1, characterized in that: The small molecule monoamine is selected from at least one of ethanolamine, N-ethylethanolamine, 2-(methylamino)ethanol and isopropanolamine.

3. A liquid-liquid two-phase carbon dioxide absorbent according to claim 1, characterized in that: The tertiary amine phase separator is selected from at least one of N,N,N,N-tetramethylethylenediamine, N,N,N',N'-tetramethyl-1,3-propylenediamine, N,N-dimethylbutylamine, triethylamine, N,N-diethylpropylamine, N,N-diethylbutylamine, N,N,N',N'',N''-pentamethyldivinyltriamine, N,N-dimethylcyclohexylamine, 1-methylpiperidine, 1-ethylpiperidine, N,N-diethylcyclohexylamine, and 1,4-diethylpiperazine.

4. The liquid-liquid two-phase carbon dioxide absorbent according to claim 1, characterized in that: The antioxidant is selected from butylated hydroxyanisole.

5. The liquid-liquid two-phase carbon dioxide absorbent according to claim 1, characterized in that: The water-soluble organic solvent is selected from at least one of N-methylpyrrolidone, sulfolane, dimethyl sulfoxide, N,N-dimethylacetamide, N,N-dimethylformamide and N,N-dimethylpropionamide.

6. A liquid-liquid two-phase carbon dioxide absorbent according to any one of claims 1 to 5, characterized in that: Calculated by mass, the liquid-liquid two-phase carbon dioxide absorbent includes: 1000-2000 mass parts of small molecule monoamine, 1000-2000 mass parts of tertiary amine phase separator, 0.5-2 mass parts of antioxidant, 1250-2250 mass parts of water-soluble organic solvent and 100-500 mass parts of water.

7. The method for preparing a liquid-liquid two-phase carbon dioxide absorbent according to any one of claims 1 to 6, characterized in that: The small molecule monoamine, tertiary amine phase separation agent, antioxidant, water-soluble organic solvent and water are uniformly mixed to obtain a liquid-liquid two-phase carbon dioxide absorbent.

8. Use of the liquid-liquid two-phase carbon dioxide absorbent according to any one of claims 1 to 6 in capturing carbon dioxide gas in exhaust gas.

9. The use according to claim 8, characterized in that: The waste gas is flue gas generated by the combustion of coal in a coal-fired power plant.

10. The use according to claim 8, characterized in that: The liquid-liquid two-phase carbon dioxide absorbent is heated to 35° C. to 55° C. to absorb carbon dioxide.

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