Low-partial-pressure CO2 catalytic absorption method and application thereof

Abstract

The invention discloses a low-partial-pressure CO2 catalytic absorption method, and belongs to the technical field of gas separation. The low-partial-pressure CO2 catalytic absorption method comprises the following steps: impregnating a rare earth metal oxide La2O3 or CeO2 on a porous alumina carrier to prepare a solid base catalyst, and catalyzing an organic amine solvent to absorb low-partial-pressure CO2 through the solid base catalyst, compared with an existing CO2 absorption method, the low-partial-pressure CO2 catalytic absorption method has the advantages that the CO2 absorption performance of the low-partial-pressure CO2 catalytic absorption method is superior to that of a single organic amine absorbent, the CO2 absorption performance and the absorption rate can be improved, the use amount of the absorbent is reduced, the size of an absorption tower and the equipment cost are reduced, and positive contribution is made to industrialization of a carbon emission reduction technology.

Description

Technical Field

[0001] The present invention relates to the field of gas separation technology, and in particular to a low partial pressure CO 2 Catalytic absorption method and its application. Background Art

[0002] In recent years, as industries such as electricity, steel, and cement use fossil energy to generate CO 2 Carbon capture, utilization and storage (CCUS) is a common technology for reducing carbon emissions. 2 Capture is the main link in the energy consumption and cost of CCUS system. Chemical absorption is considered to be one of the most effective methods to meet the needs of large-scale carbon capture, but there are a series of problems in the absorption process, such as unstable absorption performance of absorbent, low absorption efficiency, low absorption load, equipment corrosion, etc. These problems will affect CO 2 The absorption performance of the equipment is large, resulting in high investment and operating costs.

[0003] In the past, researchers have focused on the optimization and improvement of complex amine solvents, that is, mixing different types of complex amine solvents in an optimized ratio to give full play to their advantages in order to achieve the purpose of improving absorption performance.

[0004] Chinese patent CN103566735A discloses a method for removing H from natural gas. 2 S, COS, sulfides such as mercaptans and sulfides, and CO 2 A new type of absorption liquid is prepared, which includes hindered amine, alcohol amine, N-methylacetamide, salt catalyst and deionized water. The results show that the absorption liquid has significant advantages such as high desulfurization rate, low regeneration energy consumption, good stability and low price. However, it is difficult for composite amine solvents to simultaneously take into account the improvement of absorption load, fast reaction kinetics and reduction of desorption energy consumption. In addition, research in this field is already relatively mature and it is difficult to make further breakthroughs.

[0005] In response to the above problems, some researchers proposed adding catalysts to composite amine solvents to optimize the absorption of CO by amine-based solutions. 2 process, increasing CO 2 Capture efficiency.

[0006] Chinese patent CN115069068A discloses a method for fast and low-energy capture of CO 2 The method specifically uses a hydrotalcite catalyst to catalyze a tertiary amine solvent to capture CO 2 Compared with the traditional tertiary amine solvent CO 2 Absorption process. The catalyst prepared in this method is cheap and easy to obtain, has high hydrothermal stability, and a large specific surface area, which can effectively improve CO2 absorption rate, thereby achieving low energy consumption CO 2 But existing methods are not enough to capture CO 2 The absorption load and absorption rate are increased to a more ideal level.

[0007] In order to further improve the performance of the composite amine solvent on CO 2 absorption load and capture efficiency, accelerating CO 2 absorption rate, thereby reducing CO 2 Develop solid base catalysts with high catalytic performance and stability for CO 2 The absorption process has high feasibility for industrial application. Summary of the invention

[0008] The present invention aims at using a composite amine solvent to absorb CO in the prior art. 2 There are problems such as unstable absorption performance, low absorption rate and absorption load. 2 Catalytic absorption method and application thereof, using alumina as carrier, loading rare earth metal oxide La 2 O 3 or CeO 2 The solid base catalyst, combined with the organic amine solvent, forms a catalytic CO 2 Absorption system to increase CO 2 Absorption load and absorption efficiency.

[0009] In order to solve the above technical problems, the present invention provides a low partial pressure CO 2 The catalytic absorption method comprises the following steps:

[0010] S1, providing a supported catalyst; the supported catalyst comprises a carrier and an active component; the active component is a rare earth metal oxide;

[0011] S2, providing an organic amine solvent;

[0012] S3, under the action of the supported catalyst provided by S1, the flue gas is reacted with the organic amine solvent provided by S2.

[0013] According to some embodiments of the present invention, in S1, the supported catalyst is a solid base catalyst;

[0014] And / or, the carrier is at least one of alumina, silica, hydrotalcite, fly ash, montmorillonite, and attapulgite; preferably, the carrier is alumina; more preferably, the alumina is γ-Al 2 O 3 ;

[0015] And / or, the rare earth metal oxide is selected from La2 O 3 、CeO 2 At least one of; Preferably, the precursor of the rare earth metal oxide is selected from La(NO 3 ) 3 6H 2 O、Ce(NO 3 ) 3 6H 2 At least one of O.

[0016] According to some embodiments of the present invention, in S1, the loading amount of the active component in the supported catalyst is 20 wt% to 40 wt%, preferably 25 wt% to 35 wt%, for example 25 wt%.

[0017] In the present invention, La 2 O 3 or CeO 2 When rare earth metal oxides such as La are used alone, it is difficult to maintain the stability of physical properties and the utilization of basic sites is poor; alumina is a type of amphoteric oxide that can react with acids and bases, is resistant to amine degradation, has high hydrothermal stability, and can be used as a carrier to load rare earth metal oxides; therefore, La 2 O 3 or CeO 2 The rare earth metal oxides are loaded onto an alumina carrier to prepare a loaded catalyst, which can improve the dispersion and stability of the rare earth metal oxides and slow down the dissolution phenomenon.

[0018] According to some embodiments of the present invention, in S3, the flue gas is N 2 With CO 2 and / or, CO in the flue gas 2 The partial pressure is 3kPa~25kPa (i.e. CO 2 The volume fraction is 3% to 25%), preferably 10kPa to 20kPa, for example 5kPa, 10kPa, 15kPa, 20kPa.

[0019] According to some embodiments of the present invention, in S3, the added amount of the supported catalyst accounts for 5 wt% to 25 wt% of the organic amine solvent, preferably 10 wt% to 15 wt%, for example 10 wt%.

[0020] According to some embodiments of the present invention, in S2, the organic amine solvent includes at least two organic amines; preferably, the organic amine is selected from monoethanolamine (MEA), diglycolamine (DGA), diethanolamine (DEA), triethanolamine (TEA), 2-(butylamino)ethanol (BEA), diisopropanolamine (DIPA), N-methyl-diethanolamine (MDEA), 2-amino-2-methyl-1-propanol (AMP), piperazine (PZ); preferably 2-(butylamino)ethanol (BEA) and 2-amino-2-methyl-1-propanol (AMP).

[0021] According to some embodiments of the present invention, in S2, the molar ratio of 2-(butylamino)ethanol (BEA) to 2-amino-2-methyl-1-propanol (AMP) in the organic amine solvent is (1:4) to (4:1), preferably (3:2) to (3:1), for example 3:2.

[0022] According to some embodiments of the present invention, in S2, the organic amine solvent is an organic amine aqueous solution; and / or, in the organic amine solvent, the total amine concentration is 2.5 mol / L to 5 mol / L, preferably 3.5 mol / L to 4.5 mol / L, for example 4 mol / L. In the present invention, the total amine concentration is the ratio of the sum of the amounts of each organic amine substance in the organic amine aqueous solution to the volume of the organic amine aqueous solution, that is, the total amine concentration = the sum of the amounts of each organic amine substance / the volume of the organic amine aqueous solution.

[0023] According to some embodiments of the present invention, in S3, the reaction conditions include: temperature of 30°C to 60°C, preferably 40°C to 55°C, for example 40°C, 45°C, 50°C, 55°C; time of 0.5h to 5h, preferably 1.5h to 3.5h.

[0024] The second aspect of the present invention provides a low partial pressure CO 2 Application of catalytic absorption methods in gas separation, preferably for separation of CO from flue gas 2 .

[0025] Beneficial effects:

[0026] The low partial pressure CO 2 Catalytic absorption method, based on the improvement of existing organic amine solvent, 2 O 3 or CeO 2 Rare earth metal oxides such as aluminum oxide are loaded on alumina to make solid base catalysts for CO 2 During the absorption process, the solid base catalyst can form dispersed active centers at the physical level, increase the mass transfer interface area, and enhance the gas-liquid mass transfer effect, thereby increasing CO 2 Absorption load; active sites O in solid base catalysts at the chemical level2- It can act as a Lewis basic site, promote molecular transfer as an electron donor in the rate-determining step, and reduce the activation energy, thereby accelerating the CO 2 Absorption reaction rate.

[0027] The low partial pressure CO 2 Catalytic absorption method: solid base catalyst cooperates with organic amine solvent with "coordination effect" to optimize the absorption of CO by amine solution 2 process, increasing CO 2 Capture efficiency.

[0028] The present invention prepares a solid base catalyst with large specific surface area, high catalytic performance, high mechanical stability and recyclability, and cooperates with an organic amine solvent to form a catalytically enhanced CO 2 Absorption system; the low partial pressure CO 2 Catalytic absorption method optimizes CO absorption by amine-based solutions 2 process, improving the absorption of CO using organic amine solvent alone 2 When CO 2 The absorption performance is unstable, and the collection efficiency and absorption load are low.

[0029] The low partial pressure CO 2 In the catalytic absorption method, CO 2 The absorption load can reach 0.84 mol / mol, CO 2 The absorption rate can reach 7.26mmol / mol·min, CO 2 The capture efficiency can reach 95.43%, which has good industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The solid base catalyst La prepared in Example 2-3 2 O 3 -Al 2 O 3 and CeO 2 -Al 2 O 3 N 2 Isothermal adsorption-desorption curves. DETAILED DESCRIPTION

[0031] The present invention will be further described below in conjunction with the embodiments, but the present invention is not limited by these embodiments.

[0032] In the present invention, CO 2 The absorption load (mol / mol) is CO 2 The ratio of the amount of substance of to the sum of the amounts of the organic amines in the organic amine solvent is measured by CO 2The mass change of the four-necked flask before and after absorption or the calculation by acid-base titration analysis can be obtained. 2 The absorption rate is the CO absorption rate within the first 10 minutes of the reaction. 2 The ratio of the change in absorption load to time. 2 The capture efficiency refers to the absorbed CO 2 The amount of CO in the original simulated flue gas 2 The ratio of the quantities is expressed as:

[0033]

[0034] η-CO 2 Capture efficiency, %;

[0035] C in -CO in the simulated flue gas 2 Volume fraction, %;

[0036] C out - CO in simulated flue gas at outlet 2 Volume fraction, %.

[0037] In the present invention, infrared CO 2 The gas analyzer was purchased from Beijing Huayun Instrument Co., Ltd., model GHX-3010E1, with a range of 0-20%.

[0038] In the present invention, the ultrasonic immersion treatment is carried out in an ultrasonic cleaner purchased from Kunshan Jielimei Ultrasonic Instrument Co., Ltd., model KS-250DE.

[0039] In the present invention, the muffle furnace, four-necked flask, spiral condenser, gas flow meter, water bath, etc. are all common commercially available products unless otherwise specified.

[0040] In the present invention, 2-(butylamino)ethanol was purchased from Aladdin Reagent Co., Ltd. and the specification was analytical grade.

[0041] In the present invention, 2-amino-2-methyl-1-propanol was purchased from Aladdin Reagent Co., Ltd. and the specification was analytical grade.

[0042] In the present invention, γ-Al 2 O 3 It was purchased from Shanghai MacLean Biochemical Technology Co., Ltd., model A820850, particle size 4 mm, density 1.06 g / mL, specific surface area 300 m 2 / g, and the total pore volume is 0.53cm 3 / g, and the average pore size is 7.80nm.

[0043] In the present invention, the pressure of the simulated flue gas supply is 100 kPa at normal pressure.

[0044] Example 1

[0045] This embodiment provides a low partial pressure CO 2 Absorption method.

[0046] Prepare 300 mL of an organic amine aqueous solution BEA-AMP with a total amine concentration of 4 mol / L, in which the molar ratio of BEA to AMP is 3:2, and add the organic amine aqueous solution into a 500 mL four-necked flask; place the four-necked flask in a water bath and heat it to the required absorption reaction temperature of 45 °C. At a normal pressure of 100 kPa, add (simulated flue gas) N 2 and CO 2 After mixing, the mixture was introduced into a four-necked flask and the N 2 and CO 2 CO in mixed gas 2 The partial pressure of CO is 10 kPa (i.e. 2 The volume fraction is 10%); the mixed gas after the reaction is condensed by a spiral condenser and then discharged, and then the mixed gas is condensed by an infrared CO 2 Gas analyzer measures outlet CO 2 Concentration; CO 2 After 3 hours of absorption reaction, the reaction was stopped and CO 2 Absorption load, absorption rate and capture efficiency; the statistical absorption results are shown in Table 2.

[0047] Example 2

[0048] This embodiment provides a low partial pressure CO 2 Catalytic absorption method.

[0049] (1) Preparation of solid base catalyst

[0050] The La(NO 3 ) 3 6H 2 O was loaded on γ-Al with a loading amount of 25 wt%. 2 O 3 The specific operation is: take 26.56g of La(NO 3 ) 3 6H 2 O was dissolved in 50 mL of deionized water. After it was fully dissolved, 40 g of γ-Al 2 O 3 Add to La(NO 3 ) 3 6H 2O solution, and ultrasonically immersed at 20 ° C for 1 hour; then the mixed solution after ultrasonic immersion was dried at a temperature of 120 ° C for 15 hours; finally, the dried sample was placed in a muffle furnace, and the muffle furnace was heated to 500 ° C at a rate of 2 ° C / min and maintained for 4 hours, and then naturally cooled to 20 ° C to obtain La 2 O 3 The solid base catalyst with a loading of 25 wt% is labeled as La 2 O 3 -Al 2 O 3 .

[0051] (2) Characterization of solid base catalyst

[0052] The prepared solid base catalyst La 2 O 3 -Al 2 O 3 Perform N 2 Adsorption-desorption characterization test, the test results are shown in Table 1 and Figure 1 .

[0053] (3) Catalytic enhancement of CO absorption by organic amine solvents 2

[0054] Prepare 300 mL of an organic amine aqueous solution BEA-AMP with a total amine concentration of 4 mol / L, wherein the molar ratio of BEA to AMP is 3:2, add the organic amine aqueous solution into a 500 mL four-necked flask, and add 12.72 g of the above-mentioned solid base catalyst La into the organic amine aqueous solution at a rate of 10 wt%. 2 O 3 -Al 2 O 3 ;

[0055] Place the four-necked flask in a water bath and heat it to the required absorption reaction temperature of 45°C. At a normal pressure of 100 kPa, add (simulated flue gas) N 2 and CO 2 After mixing, the mixture was introduced into a four-necked flask and the N 2 and CO 2 CO in the mixed gas 2 The partial pressure of CO is 10 kPa (i.e. 2 The volume fraction is 10%); the mixed gas after the reaction is condensed by a spiral condenser and then discharged, and then the mixed gas is condensed by an infrared CO 2 Gas analyzer measures outlet CO 2 Concentration; CO 2 After 3 hours of absorption reaction, the reaction was stopped and CO 2The absorption load, absorption rate and capture efficiency, and the statistical absorption results are shown in Table 2.

[0056] Comparative Example 1

[0057] The difference between Comparative Example 1 and Example 2 is that in step (3), 12.72 g of γ-Al 2 O 3 Replace solid base catalyst La 2 O 3 -Al 2 O 3 , other conditions remain unchanged, and the statistical absorption results are shown in Table 2.

[0058] Comparative Example 2

[0059] The difference between Comparative Example 2 and Example 2 is that in step (3), 12.72 g of La 2 O 3 Replace solid base catalyst La 2 O 3 -Al 2 O 3 , other conditions remain unchanged, and the statistical absorption results are shown in Table 2.

[0060] Example 3

[0061] This embodiment provides a low partial pressure CO 2 Catalytic absorption method.

[0062] (1) Preparation of solid base catalyst

[0063] The Ce(NO 3 ) 3 6H 2 O was loaded on γ-Al with a loading amount of 25 wt%. 2 O 3 The specific operation is: take 25.23g of Ce(NO 3 ) 3 6H 2 O was dissolved in 50 mL of deionized water. After it was fully dissolved, 40 g of γ-Al 2 O 3 Add to Ce(NO 3 ) 3 6H 2 O solution and ultrasonically immersed at 20°C for 1h; then the mixed solution after ultrasonic immersion was dried at 120°C for 15h; finally, the dried sample was placed in a muffle furnace, the muffle furnace was heated to 500°C at a rate of 2°C / min and maintained for 4h, and then naturally cooled to 20°C to obtain CeO 2Solid base catalyst with a loading of 25 wt%, labeled as CeO 2 -Al 2 O 3 .

[0064] (2) Characterization of solid base catalyst

[0065] The prepared solid base catalyst CeO 2 -Al 2 O 3 Perform N 2 Adsorption-desorption characterization test, the test results are shown in Table 1 and Figure 1 .

[0066] (3) Catalytic absorption of CO by organic amine solvent 2

[0067] Prepare 300 mL of an organic amine aqueous solution BEA-AMP with a total amine concentration of 4 mol / L, wherein the molar ratio of BEA to AMP is 3:2, add the organic amine aqueous solution into a 500 mL four-necked flask, and add 12.72 g of the above-mentioned solid base catalyst CeO to the organic amine aqueous solution at a rate of 10 wt%. 2 -Al 2 O 3 ;

[0068] Place the four-necked flask in a water bath and heat it to the required absorption reaction temperature of 45°C. At a normal pressure of 100 kPa, add (simulated flue gas) N 2 and CO 2 After mixing, the mixture was introduced into a four-necked flask and the N 2 and CO 2 CO in mixed gas 2 The partial pressure of CO is 10 kPa (i.e. 2 The volume fraction is 10%); the mixed gas after the reaction is condensed by a spiral condenser and then discharged, and then discharged by CO 2 Infrared gas analyzer to measure outlet CO 2 Concentration; CO 2 After 3 hours of absorption reaction, the reaction was stopped and CO 2 The absorption load, absorption rate and capture efficiency, and the statistical absorption results are shown in Table 2.

[0069] Comparative Example 3

[0070] The difference between Comparative Example 3 and Example 3 is that in step (3), 12.72 g of CeO 2 Replace solid base catalyst CeO 2 -Al 2 O 3, other conditions remain unchanged, and the statistical absorption results are shown in Table 2.

[0071] Table 1

[0072]

[0073] From the data in Table 1, we can see that compared with pure γ-Al 2 O 3 In contrast, when preparing the solid base catalyst, La 2 O 3 or CeO 2 Loading to γ-Al 2 O 3 After the solid base catalyst La 2 O 3 -Al 2 O 3 and CeO 2 -Al 2 O 3 The specific surface area, total pore volume and average pore diameter of γ-Al 2 O 3 After the active components are loaded on the skeleton, some of the pores are blocked; 2 -Al 2 O 3 In comparison, La 2 O 3 -Al 2 O 3 The specific surface area (282m 2 / g), total pore volume (0.49cm 3 / g) and the average pore size (7.54nm) are larger, indicating that La 2 O 3 -Al 2 O 3 There is a more developed pore structure, which is conducive to exposing more basic sites.

[0074] Furthermore, from γ-Al 2 O 3 , solid base catalyst La 2 O 3 -Al 2 O 3 and CeO 2 -Al 2 O 3 N 2 Adsorption-desorption isotherms ( Figure 1 ) shows that the adsorption-desorption isotherms of the solid base catalysts are all type IV, and the shapes of the hysteresis loops are all H3 type; 2 -Al 2 O 3In comparison, La 2 O 3 -Al 2 O 3 The hysteresis loop in is significantly larger, indicating that La 2 O 3 -Al 2 O 3 More mesoporous structures are formed.

[0075] Table 2

[0076]

[0077] As shown in Table 2, compared with the BEA-AMP solvent without adding catalyst in Example 1, the CO 2 The absorption load, absorption rate and capture efficiency of the catalyst were increased. Furthermore, compared with the single catalyst γ-Al 2 O 3 ,La 2 O 3 and CeO 2 The composite catalyst La 2 O 3 -Al 2 O 3 and CeO 2 -Al 2 O 3 After adding to the organic amine solvent, CO 2 The absorption load, absorption rate and capture efficiency of the catalyst La 2 O 3 -Al 2 O 3 The post-reaction system is CO 2 The absorption performance is the best, CO 2 The absorption load can reach 0.83 mol / mol, CO 2 The absorption rate can reach 7.14mmol / mol·min, CO 2 The capture efficiency can reach 95.43%, which indicates that the rare earth metal oxides loaded on γ-Al 2 O 3 The solid base catalyst prepared above can provide abundant surface alkaline sites and porous surface, increase the gas-liquid contact time, promote the formation of carbamate and bicarbonate, and thus improve CO 2 Absorption capacity and absorption rate.

[0078] Embodiment 4-6

[0079] The difference between Example 4-6 and Example 2 is that the catalytic organic amine solvent absorbs CO2 After the completion, the catalyst La was separated 2 O 3 -Al 2 O 3 After washing, the catalyst La was dried at 120°C. 2 O 3 -Al 2 O 3 Recycling, other conditions remain unchanged; catalyst La 2 O 3 -Al 2 O 3 The number of cycles used for CO 2 The effects of absorption load, absorption rate and capture efficiency are shown in Table 3.

[0080] Table 3

[0081] Example Example 4 Example 5 Example 6 <![CDATA[Usage times of catalyst La 2 O 3 -Al 2 O 3 > 2nd time 3rd 4th <![CDATA[CO 2 Absorption load (mol / mol)]]> 0.81 0.80 0.77 <![CDATA[CO 2 Absorption rate (mmol / mol·min)]]> 7.08 7.05 6.97 <![CDATA[CO 2 Collection efficiency (%)]]> 95.04 94.96 93.84

[0082] It can be seen from Table 3 that the catalyst La 2 O 3 -Al 2 O 3 After being recycled for 4 times, it still has high catalytic activity, CO 2 The absorption load can reach 0.77 mol / mol, CO 2 The absorption rate can reach 6.97mmol / mol·min, CO 2 The capture efficiency can reach 93.84%, which shows that the solid base catalyst La prepared by the impregnation method in the present invention 2 O 3 -Al 2 O 3 It has good stability and high economic practicality.

[0083] Embodiment 7-9

[0084] The difference between Example 7-9 and Example 2 is that the catalytic organic amine solvent absorbs CO 2 The reaction temperatures were set to 40°C, 50°C, and 55°C respectively, and other conditions remained unchanged to carry out the catalytic organic amine solvent absorption of CO 2 , catalyst La 2 O 3 -Al 2 O 3 CO 2 The influence of absorption load, absorption rate and capture efficiency is shown in Table 4.

[0085] Table 4

[0086] Example Example 7 Example 8 Example 9 Temperature(℃) 40 50 55 <![CDATA[CO 2 Absorption load (mol / mol)]]> 0.78 0.75 0.74 <![CDATA[CO 2 Absorption rate (mmol / mol·min)]]> 6.83 6.92 6.74 <![CDATA[CO 2 Collection efficiency (%)]]> 92.48 92.73 91.92

[0087] It can be seen from Table 4 that when the reaction temperature is in the range of 40℃~55℃, CO 2 Absorption load 0.74mol / mol~0.78mol / mol, CO 2 Absorption rate 6.74mmol / mol·min~6.92mmol / mol·min, CO 2 The capture efficiency is 91.92% to 92.73%, indicating that within the reaction temperature range, the catalytic absorption system has a good effect on low partial pressure CO 2 Has good absorption properties.

[0088] Examples 10-15

[0089] The difference between Examples 10-15 and Example 2 is that the CO in the simulated flue gas introduced is 2 In Examples 10-15, the CO in the simulated flue gas is 2 The partial pressure of CO was used as a variable to conduct the experiment. 2 The partial pressure is 3kPa, 5kPa, 15kPa, 20kPa, 25kPa, 30kPa, and other conditions remain unchanged to carry out the catalytic organic amine solvent absorption of CO 2 ; Simulate CO in flue gas 2 The partial pressure of CO 2 The influence of absorption load, absorption rate and capture efficiency is shown in Table 5.

[0090] Table 5

[0091] Example 10 11 12 13 14 15 <![CDATA[CO 2 Partial pressure (kPa)]]> 3 5 15 20 25 30 <![CDATA[CO 2 Absorption load (mol / mol)]]> 0.69 0.78 0.84 0.81 0.72 0.67 <![CDATA[CO 2 Absorption rate (mmol / mol·min)]]> 6.03 6.87 7.26 7.08 6.17 5.95 <![CDATA[CO 2 Collection efficiency (%)]]> 88.81 93.81 95.37 94.34 91.87 89.03

[0092] It can be seen from Table 5 that in the simulated flue gas, CO 2 The partial pressure of CO is in the range of 5kPa to 25kPa. 2 The absorption load is 0.72mol / mol~0.84mol / mol, CO 2 The absorption rate is 6.17mmol / mol·min~7.26mmol / mol·min, CO 2 The capture efficiency is 91.87% to 95.37%, which indicates that under different CO 2 The catalytic absorption system is effective for the absorption of CO in simulated flue gas under different partial pressures. 2 All have good absorption effects. In addition, when simulating CO in flue gas 2 When the partial pressure of CO is lower than 5 kPa or higher than 25 kPa, the catalytic absorption system 2 The absorption effect is poor.

[0093] In summary, the low partial pressure CO 2In the catalytic absorption method, solid base catalyst is used to catalyze the organic amine solvent to absorb CO in the simulated flue gas. 2 It has high absorption load, absorption rate and capture efficiency, and is also applied to CO 2 The solid base catalyst in the absorption process has high catalytic activity, is recyclable, has a long service life, and has strong feasibility for industrial application.

[0094] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A low partial pressure CO2 catalytic absorption method, characterized in that: The following steps are involved: S1, providing a supported catalyst; the supported catalyst comprises a carrier and an active component; the active component is a rare earth metal oxide; S2, providing an organic amine solvent; S3, under the action of the supported catalyst provided by S1, the flue gas is reacted with the organic amine solvent provided by S2.

2. The low partial pressure CO2 catalytic absorption method according to claim 1, characterized in that: In S1, the supported catalyst is a solid base catalyst; And / or, the carrier is selected from at least one of alumina, silica, hydrotalcite, fly ash, montmorillonite, and attapulgite; preferably, the carrier is alumina; more preferably, the alumina is γ-Al2O3; And / or, the rare earth metal oxide is selected from at least one of La2O3 and CeO2; preferably, the precursor of the rare earth metal oxide is selected from at least one of La(NO3)3·6H2O and Ce(NO3)3·6H2O.

3. The low partial pressure CO2 catalytic absorption method according to claim 1 or 2, characterized in that: In S1, the loading amount of the active component in the supported catalyst is 20 wt% to 40 wt%, preferably 25 wt% to 35 wt%.

4. The low partial pressure CO2 catalytic absorption method according to any one of claims 1 to 3, characterized in that: In S2, the organic amine solvent includes at least two organic amines; preferably, the organic amine is selected from monoethanolamine, diglycolamine, diethanolamine, triethanolamine, 2-(butylamino)ethanol, diisopropanolamine, N-methyl-diethanolamine, 2-amino-2-methyl-1-propanol, and piperazine.

5. The low partial pressure CO2 catalytic absorption method according to any one of claims 1 to 4, characterized in that: In S2, the organic amine solvent is an organic amine aqueous solution; and / or, the total amine concentration in the organic amine solvent is 2.5 mol / L to 5 mol / L, preferably 3.5 mol / L to 4.5 mol / L.

6. The low partial pressure CO2 catalytic absorption method according to any one of claims 1 to 5, characterized in that: In S3, the flue gas is a mixture of N2 and CO2; and / or the partial pressure of CO2 in the flue gas is 3 kPa to 25 kPa, preferably 10 kPa to 20 kPa.

7. The low partial pressure CO2 catalytic absorption method according to any one of claims 1 to 6, characterized in that: In S3, the added amount of the supported catalyst accounts for 5wt% to 25wt% of the organic amine solvent, preferably 10wt% to 15wt%.

8. The low partial pressure CO2 catalytic absorption method according to any one of claims 1 to 7, characterized in that: In S3, the reaction conditions include: temperature of 30°C to 60°C, preferably 40°C to 55°C; time of 0.5h to 5h, preferably 1.5h to 3.5h.

9. Use of the low partial pressure CO2 catalytic absorption method according to any one of claims 1 to 8 in gas separation, preferably for separating CO2 from flue gas.

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