Carbon dioxide adsorbent, preparation method and application thereof

Abstract

The application discloses a carbon dioxide adsorbent and a preparation method and application thereof. The adsorbent comprises a carrier, an active component and an auxiliary agent which are loaded on the carrier. The carrier is titanium dioxide, the active component is potassium carbonate, and the auxiliary agent is vanadium pentoxide. The preparation method comprises the following steps: (1) a sol is obtained by mixing a titanium source, an auxiliary agent precursor, ethanol and acid liquid with polymethyl methacrylate microspheres as a template, and then the adsorbent precursor is obtained through filtration, drying and calcination; and (2) the adsorbent precursor obtained in the step (1) is mixed with an active component precursor, and then the adsorbent is obtained through drying and calcination. The prepared adsorbent has good low-temperature reaction activity, and the regeneration reaction temperature is low, so that the energy consumption in the regeneration process is greatly reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of carbon emission reduction, and relates to a carbon dioxide adsorption material, in particular to a low-temperature carbon dioxide solid adsorbent and a preparation method thereof. BACKGROUND

[0002] In recent years, with the large consumption of fossil energy and the influence of human activities, the greenhouse gas, especially carbon dioxide, has increased significantly, and climate change has become one of the most severe challenges facing the sustainable development of mankind. The World Meteorological Organization released a report that the concentration of carbon dioxide in the global atmosphere broke through 410 ppm in 2019, setting a new high.

[0003] Carbon dioxide capture has been considered as a key technology for reducing carbon dioxide emissions in fossil energy power generation and industrial processes. Compared with the traditional solvent absorption process, the solid adsorbent treatment method has attracted widespread attention due to its low energy consumption, small pollution and simple process. The solid adsorbent is divided into high-temperature solid adsorbent, medium-temperature solid adsorbent, low-temperature solid adsorbent and the like according to working conditions; among them, the low-temperature solid adsorbent is mainly used for carbon dioxide removal in raw gas such as natural gas and coal gas, and the working temperature of the adsorbent is usually lower than 200 DEG C, including molecular sieves, MOFs, carbon-based and carbonate materials.

[0004] The renewable alkali metal carbonate adsorbent carbon dioxide removal technology has the advantages of low regeneration temperature, small energy consumption and large adsorption capacity, and is a promising carbon dioxide capture technology. The adsorbent is mainly sodium carbonate and potassium carbonate, which directly adsorbs carbon dioxide by chemical reaction with carbon dioxide. Through the cycle of low-temperature adsorption and high-temperature desorption, the capture of carbon dioxide and the regeneration of the adsorbent are realized, and the specific reaction process when potassium carbonate is used as the adsorbent is as follows:

[0005] Carbonation reaction: CO2+ K2CO3+ H2O ⇋ 2KHCO3

[0006] Regeneration reaction: 2KHCO3⇋ K2CO3+ CO2+ H2O

[0007] When pure carbonate is used as the adsorbent, the carbonation reaction rate is very low, the reaction activity is poor, and the pure carbonate has poor wear resistance and low cycle reaction performance. Therefore, people load active substances on different carriers to improve the reaction performance of the adsorbent.

[0008] CN106163997A stabilizes alumina precursor by calcination or steam treatment, impregnates basic or alkaline earth compound in stabilized alumina, obtains stabilized alumina carrier, and exhibits good cyclic regeneration performance in carbon dioxide adsorption. CN103611491A uses mesoporous alumina as carrier, impregnates potassium carbonate to synthesize alkali functionalized mesoporous alumina-based composite adsorbent, and has advantages of low cost and high cycle performance. However, when Al2O3 is used as carrier, new carbonate species is easily formed in carbonation process, which can be decomposed at high temperature, and increase of regeneration temperature increases energy consumption in reaction process. SUMMARY

[0009] In view of the low carbonation reaction rate and high regeneration energy consumption in the prior art, the present application mainly aims to provide a carbon dioxide adsorbent and a preparation method and application thereof, the prepared adsorbent has good low-temperature reactivity, low regeneration reaction temperature, and greatly reduces the energy consumption in the regeneration process.

[0010] The first aspect of the present application provides a carbon dioxide adsorbent, which comprises a carrier, an active component and an additive supported on the carrier, the carrier is titanium dioxide, the active component is potassium carbonate, and the additive is vanadium pentoxide.

[0011] Further, in the adsorbent, the weight content of potassium carbonate is 5-45%, the weight content of V2O5 is 0.1-15%, and the weight content of the carrier is 40-80%.

[0012] The second aspect of the present application provides a preparation method of a carbon dioxide adsorbent, comprising the following steps:

[0013] (1) using polymethyl methacrylate (PMMA) microspheres as a template, mixing a titanium source, an additive precursor, ethanol and acid solution to obtain a sol, and then filtering, drying and calcining to obtain an adsorbent precursor;

[0014] (2) mixing the adsorbent precursor obtained in step (1) with an active component precursor, and then drying and calcining to obtain an adsorbent.

[0015] Further, in the preparation method of the carbon dioxide adsorbent, the particle size of the polymethyl methacrylate (PMMA) microspheres is 100-1000 nm.

[0016] Further, in the preparation method of the carbon dioxide adsorbent, the pore size of the adsorbent is 20-2000 nm.

[0017] Further, in the preparation method of the carbon dioxide adsorbent, the titanium source is one or more of tetrabutyl titanate, titanium tetrachloride and titanium isopropoxide, and the titanium source is preferably tetrabutyl titanate.

[0018] Further, in the preparation method of the carbon dioxide adsorbent, the acid liquid is one or more of glacial acetic acid, citric acid, and the like, and preferably is glacial acetic acid.

[0019] Further, in the preparation method of the carbon dioxide adsorbent, the assistant precursor is at least one of ammonium metavanadate (NH4VO3) and vanadium pentoxide (V2O5), and preferably is ammonium metavanadate.

[0020] Further, in the preparation method of the carbon dioxide adsorbent, the drying condition in step (1) is as follows: the drying temperature is 20-60°C, and the drying time is 2-6h, and further preferably, the drying is performed under vacuum; and the calcination condition is as follows: the calcination temperature is 400-900°C, and the calcination time is 2-6h.

[0021] Further, in the preparation method of the carbon dioxide adsorbent, the adding amount of the polymethyl methacrylate template agent in step (1) is 10-100g / mol of the titanium source.

[0022] Further, in the preparation method of the carbon dioxide adsorbent, the molar ratio of the titanium source and the assistant precursor in step (1) is 1:0.01-0.5 in terms of elements.

[0023] Further, in the preparation method of the carbon dioxide adsorbent, the molar ratio of the titanium source and the acid liquid in step (1) is 1:0.1-0.5 in terms of elements.

[0024] Further, in the preparation method of the carbon dioxide adsorbent, the active component precursor in step (2) is a potassium salt, and specifically can be one or both of potassium carbonate and potassium bicarbonate.

[0025] Further, in the preparation method of the carbon dioxide adsorbent, the drying condition in step (2) is as follows: the drying temperature is 60-150°C, preferably is 100-120°C, and the drying time is 4-48h, preferably is 6-36h, and more preferably is 8-24h.

[0026] Further, in the preparation method of the carbon dioxide adsorbent, the calcination condition in step (2) is as follows: the calcination temperature is 100-400°C, preferably is 150-350°C, and more preferably is 200-300°C, and the calcination time is 3-10h, preferably is 4-8h.

[0027] The third aspect of the present application provides a carbon dioxide adsorbent obtained by the above preparation method.

[0028] The fourth aspect of the present application provides an application of the above carbon dioxide adsorbent in absorbing carbon dioxide.

[0029] Further, in the above application, a fixed bed or fluidized bed reactor is used, the reaction temperature is 50-100℃, the reaction pressure is 0.1-5Mpa, the volume space velocity is 50-1000h -1 The adsorbent is regenerated under N2 atmosphere, and the regeneration reaction temperature is 100-300℃.

[0030] Compared with the prior art, the carbon dioxide adsorbent and the preparation method thereof have the beneficial effects that:

[0031] 1. The carbon dioxide adsorbent provided by the application uses macroporous ordered titanium dioxide-vanadium pentoxide as a carrier, and V2O5 is introduced in situ during the preparation of the titanium dioxide. On the one hand, the titanium dioxide has a high specific surface area and a pore structure, which is beneficial to the dispersion of the active component potassium carbonate, increases the contact efficiency with CO2 molecules, and improves the adsorption performance. On the other hand, the introduction of the dopant V2O5 can improve the coverage of CO2 on the surface of the adsorbent together with TiO2, promote the diffusion of carbon dioxide molecules, and thus improve the carbonation reaction rate.

[0032] 2. The components V2O5 and TiO2 in the carrier of the carbon dioxide adsorbent provided by the application will not form a difficult-to-decompose carbonate species with the active component potassium carbonate, which is beneficial to improving the cyclic reaction performance of the adsorbent.

[0033] 3. The carbon dioxide adsorbent provided by the application uses potassium carbonate as the active component, has higher reaction activity, and has low reaction temperature and regeneration temperature, and small energy consumption. DETAILED DESCRIPTION

[0034] The catalyst, the preparation method and the application thereof provided by the application will be further described through examples below, but the application should not be considered to be limited to the following examples.

[0035] Example 1

[0036] 20.6g of tetrabutyl titanate and 0.4g of NH4VO3 are added dropwise into 60ml of an ethanol solution, 0.05mol of glacial acetic acid is further added, and stirring is performed for 1h to obtain a sol system. 10.0g of polymethyl methacrylate (PMMA) microsphere templates (with a particle size of 800nm) are added to the sol system, filtration, vacuum drying at 40℃ for 2h, and calcination at 500℃ for 4h are performed to obtain an ordered macroporous carrier. Potassium bicarbonate is used as a precursor to prepare an impregnation solution, 10.0g of the carrier is immersed in the solution, drying is performed at 110℃ for 10h, and calcination is performed at 200℃ for 4h to obtain an adsorbent. The average pore size of the adsorbent is 103nm. The potassium carbonate content of the adsorbent is 28.8wt%, the V2O5 content is 3.9wt%, and the rest is the carrier.

[0037] The adsorbent material is used for low-temperature CO2 adsorption experiments in a fixed bed, and the space velocity is 300h -1, temperature 60℃, 0.1 MPa, CO2 and water vapor mixture was introduced to carry out adsorption. Then, under the nitrogen atmosphere, the temperature was raised to 150℃ to carry out adsorbent decomposition regeneration, to complete a cycle. After 10 cycles, the CO2 adsorption performance remained at 1.5 mmol / g adsorbent.

[0038] Example 2

[0039] Take 11.2g titanium tetrachloride, 0.4g NH4VO3 drop into 40ml ethanol solution, then add 0.08mol glacial acetic acid stirring 1h after getting sol system. 8.8g polymethyl methacrylate (PMMA) microspheres template (particle size of 800nm) is added to the sol system, after filtration, 40℃ vacuum drying 2h, 550℃ calcination 6h after getting ordered macroporous carrier. With potassium bicarbonate as precursor preparation impregnation solution, 10.0g carrier is immersed into the solution, after 110℃ drying 10h, 250℃ calcination 6h after getting adsorbent. The average pore size of the adsorbent is 218nm. The adsorbent, by weight, the potassium carbonate content is 32.5wt%, V2O5 content is 3.7wt%, the rest is carrier.

[0040] The adsorbent material is used for fixed bed low temperature CO2 adsorption experiment, under the condition of 300h -1 , temperature 60℃, 0.2 MPa, CO2 and water vapor mixture was introduced to carry out adsorption, then, under the nitrogen atmosphere, the temperature was raised to 150℃ to carry out adsorbent decomposition regeneration, to complete a cycle. After 10 cycles, the CO2 adsorption performance remained at 1.3 mmol / g adsorbent.

[0041] Example 3

[0042] Take 11.2g titanium tetrachloride, 0.4g NH4VO3 drop into 40ml ethanol solution, then add 0.08mol glacial acetic acid stirring 1h after getting sol system. 8.8g polymethyl methacrylate (PMMA) microspheres template (particle size of 800nm) is added to the sol system, after filtration, 40℃ vacuum drying 2h, 550℃ calcination 6h after getting ordered macroporous carrier. With potassium bicarbonate as precursor preparation impregnation solution, 10.0g carrier is immersed into the solution, after 110℃ drying 10h, 250℃ calcination 6h after getting adsorbent. The average pore size of the adsorbent is 218nm. The adsorbent, by weight, the potassium carbonate content is 32.5wt%, V2O5 content is 3.7wt%, the rest is carrier.

[0043] The adsorbent material is used for fixed bed low temperature CO2 adsorption experiment, under the condition of 300h -1, temperature 65℃, 0.1 MPa, CO2 and water vapor mixture was introduced to carry out adsorption, then in nitrogen atmosphere, temperature was raised to 130℃ to carry out adsorbent decomposition regeneration, to complete a cycle. After 10 cycles, CO2 adsorption performance remained at 1.2 mmol / g adsorbent.

[0044] Example 4

[0045] Take 40.0 g of tetrabutyl titanate, 0.8 g of NH4VO3, drop into 80 ml of ethanol solution, then add 0.08 mol of glacial acetic acid, stir for 1 h to obtain a sol system. 15.0 g of polymethyl methacrylate (PMMA) microsphere template (particle size 600 nm) is added to the sol system, filtered, vacuum dried at 40℃ for 2 h, calcined at 550℃ for 6 h to obtain an ordered macroporous carrier. Potassium bicarbonate is used as a precursor to prepare an impregnation solution, 5.0 g of the carrier is immersed in the solution, dried at 110℃ for 10 h, calcined at 200℃ for 6 h to obtain an adsorbent. The average pore size of the adsorbent is 233 nm. The adsorbent contains 22.8wt% of potassium carbonate, 4.9wt% of V2O5, and the rest is the carrier.

[0046] The adsorbent material is used for fixed bed low temperature CO2 adsorption experiment, under the condition of space velocity 400h -1 , temperature 70℃, 0.1 MPa, CO2 and water vapor mixture is introduced to carry out adsorption, then in nitrogen atmosphere, temperature is raised to 180℃ to carry out adsorbent decomposition regeneration, to complete a cycle. After 10 cycles, CO2 adsorption performance remains at 1.6 mmol / g adsorbent.

[0047] Example 5

[0048] Take 40.0 g of tetrabutyl titanate, 0.8 g of NH4VO3, drop into 80 ml of ethanol solution, then add 0.08 mol of glacial acetic acid, stir for 1 h to obtain a sol system. 15.0 g of polymethyl methacrylate (PMMA) microsphere template (particle size 600 nm) is added to the sol system, filtered, vacuum dried at 40℃ for 2 h, calcined at 550℃ for 6 h to obtain an ordered macroporous carrier. Potassium bicarbonate is used as a precursor to prepare an impregnation solution, 5.0 g of the carrier is immersed in the solution, dried at 110℃ for 10 h, calcined at 200℃ for 6 h to obtain an adsorbent. The average pore size of the adsorbent is 233 nm. The adsorbent contains 22.8wt% of potassium carbonate, 4.9wt% of V2O5, and the rest is the carrier.

[0049] The adsorbent material is used for fixed bed low temperature CO2 adsorption experiment, under the condition of space velocity 400h -1temperature 60°C, 0.1 MPa, then desorption and regeneration of the adsorbent by heating to 150°C under nitrogen atmosphere, to complete one cycle. After 10 cycles, the CO2adsorption capacity remains at 1.2 mmol / g adsorbent.

[0050] Example 6

[0051] Take 35.5 g of tetrabutyl titanate, 1.9 g of V2O5, drop into 80 ml of ethanol solution, then add 0.08 mol of glacial acetic acid to obtain a sol system. 13.0 g of polymethyl methacrylate (PMMA) microsphere template (particle size 600 nm) is added to the sol system, filtered, vacuum dried at 40°C for 2h, and calcined at 550°C for 6h to obtain an ordered macroporous carrier. Potassium bicarbonate is used as a precursor to prepare an impregnation solution, 5.0 g of the carrier is immersed in the solution, dried at 110°C for 10h, and calcined at 180°C for 6h to obtain the adsorbent. The average pore size of the adsorbent is 120 nm. The adsorbent contains 37.2wt% of potassium carbonate, 11.7wt% of V2O5, and the rest is the carrier.

[0052] The adsorbent material is used for low-temperature CO2adsorption experiments in a fixed bed, with a space velocity of 400h -1 -1, temperature 60°C, 0.1 MPa, then desorption and regeneration of the adsorbent by heating to 130°C under nitrogen atmosphere, to complete one cycle. After 10 cycles, the CO2adsorption capacity remains at 1.3 mmol / g adsorbent.

[0053] Example 7

[0054] Take 35.5 g of tetrabutyl titanate, 1.9 g of V2O5, drop into 80 ml of ethanol solution, then add 0.08 mol of glacial acetic acid to obtain a sol system. 13.0 g of polymethyl methacrylate (PMMA) microsphere template (particle size 600 nm) is added to the sol system, filtered, vacuum dried at 40°C for 2h, and calcined at 550°C for 6h to obtain an ordered macroporous carrier. Potassium bicarbonate is used as a precursor to prepare an impregnation solution, 5.0 g of the carrier is immersed in the solution, dried at 110°C for 10h, and calcined at 180°C for 6h to obtain the adsorbent. The average pore size of the adsorbent is 120 nm. The adsorbent contains 37.2wt% of potassium carbonate, 11.7wt% of V2O5, and the rest is the carrier.

[0055] The adsorbent material is used for low-temperature CO2adsorption experiments in a fixed bed, with a space velocity of 400h -1The adsorbent was adsorbed by introducing a mixture of CO2 and water vapor at 60℃ and 0.3MPa, followed by decomposition and regeneration of the adsorbent under a nitrogen atmosphere at 150℃, completing one cycle. After 10 cycles, the CO2 adsorption performance remained at 1.1 mmol / g adsorbent.

[0056] Example 8

[0057] 35.0 g of tetrabutyl titanate and 0.75 g of NH4VO3 were added dropwise to 80 ml of ethanol solution, followed by the addition of 0.1 mol of glacial acetic acid and stirring for 1 h to obtain a sol system. 10.0 g of polymethyl methacrylate (PMMA) microsphere template (500 nm particle size) was added to the sol system, filtered, vacuum dried at 40 °C for 2 h, and calcined at 550 °C for 6 h to obtain an ordered macroporous support. An impregnation solution was prepared using potassium bicarbonate as a precursor, and 5.0 g of the support was impregnated in the solution. After drying at 110 °C for 10 h and calcining at 200 °C for 6 h, the adsorbent was obtained. The average pore size of the adsorbent was 268 nm. By weight, the adsorbent contained 30.8 wt% potassium carbonate, 5.8 wt% V2O5, and the remainder was the support.

[0058] The adsorbent material was used in a fixed-bed low-temperature CO2 adsorption experiment at a space velocity of 400 h⁻¹. -1 The adsorbent was adsorbed by introducing a mixture of CO2 and water vapor at 50℃ and 0.1MPa, and then regenerated by heating to 120℃ under a nitrogen atmosphere, completing one cycle. After 10 cycles, the CO2 adsorption performance remained at 1.4 mmol / g adsorbent.

[0059] Comparative Example 1

[0060] The process was essentially the same as in Example 1, except that vanadium was not added during the preparation of the support. The initial CO2 adsorption capacity of the adsorbent was 0.7 mmol / g adsorbent, which decreased to 0.34 mmol / g adsorbent after 10 cycles.

[0061] Comparative Example 2

[0062] Silica, vanadium pentoxide, and potassium carbonate were directly mixed and used as adsorbents. The initial CO2 adsorption capacity of the adsorbent was 0.4 mmol / g adsorbent, which decreased to 0.11 mmol / g adsorbent after 10 cycles.

Claims

1. A carbon dioxide adsorbent, the adsorbent comprising a carrier and an active component and an auxiliary agent supported on the carrier, the carrier being titanium dioxide, the active component being potassium carbonate, and the auxiliary agent being vanadium pentoxide; a method for preparing the carbon dioxide adsorbent comprising the following steps: (1) mixing a titanium source, an auxiliary agent precursor, ethanol, and an acid solution to obtain a sol using polymethyl methacrylate (PMMA) microspheres as a template, and then filtering, drying, and calcining to obtain an adsorbent precursor; the auxiliary agent precursor being at least one of ammonium metavanadate and vanadium pentoxide; (2) mixing the adsorbent precursor obtained in step (1) with an active component precursor, and then drying and calcining to obtain the adsorbent.

2. The carbon dioxide adsorbent according to claim 1, characterized by: The weight content of potassium carbonate is 5-45%, the weight content of V2O5 is 0.1-15%, and the weight content of the carrier is 40-80%, based on the weight of the adsorbent.

3. A method for preparing a carbon dioxide adsorbent, comprising the following steps: (1) mixing a titanium source, an auxiliary agent precursor, ethanol, and an acid solution to obtain a sol using polymethyl methacrylate (PMMA) microspheres as a template, and then filtering, drying, and calcining to obtain an adsorbent precursor; the auxiliary agent precursor being at least one of ammonium metavanadate and vanadium pentoxide; (2) mixing the adsorbent precursor obtained in step (1) with an active component precursor, and then drying and calcining to obtain the adsorbent.

4. The method for preparing the carbon dioxide adsorbent according to claim 3, characterized by: The particle size of the polymethyl methacrylate microspheres is 100-1000 nm.

5. The method for preparing the carbon dioxide adsorbent according to claim 3, characterized in that: The titanium source is one or more of tetrabutyl titanate, titanium tetrachloride, and titanium isopropoxide.

6. The method for preparing the carbon dioxide adsorbent according to claim 3, characterized in that: The titanium source is tetrabutyl titanate.

7. The method for preparing the carbon dioxide adsorbent according to claim 3, characterized in that: The acid solution is one or more of glacial acetic acid and citric acid.

8. The method for preparing the carbon dioxide adsorbent according to claim 3, characterized in that: The acid solution is glacial acetic acid.

9. The method for preparing the carbon dioxide adsorbent according to claim 3, characterized in that: The auxiliary agent precursor is ammonium metavanadate.

10. The method for preparing the carbon dioxide adsorbent according to claim 3, characterized in that: In step (1), the drying conditions are as follows: the drying temperature is 20-60°C, the drying time is 2-6 h, and the drying is performed under vacuum; the calcining conditions are as follows: the calcining temperature is 400-900°C, and the calcining time is 2-6 h.

11. The method for preparing the carbon dioxide adsorbent according to claim 3, characterized in that: In step (1), the addition amount of the polymethyl methacrylate template agent is 10-100 g / mol of the titanium source.

12. The method for preparing the carbon dioxide adsorbent according to claim 3, characterized in that: In step (1), the molar ratio of the titanium source to the auxiliary agent precursor, on an elemental basis, is 1:0.01-0.

5.

13. The method for preparing the carbon dioxide adsorbent according to claim 3, characterized in that: In step (1), the molar ratio of the titanium source to the acid solution, on an elemental basis, is 1:0.1-0.

5.

14. The method for preparing the carbon dioxide adsorbent according to claim 3, characterized in that: In step (2), the active component precursor is a potassium salt.

15. The method for preparing the carbon dioxide adsorbent according to claim 3, characterized in that: In step (2), the active component precursor is one or both of potassium carbonate and potassium bicarbonate.

16. The method for preparing the carbon dioxide adsorbent according to claim 3, characterized in that: In step (2), the drying conditions are as follows: the drying temperature is 60-150°C, and the drying time is 4-48 h.

17. The method for preparing the carbon dioxide adsorbent according to claim 3, characterized in that: In step (2), the drying conditions are as follows: the drying temperature is 100-120°C, and the drying time is 6-36 h.

18. The method of claim 3, wherein the carbon dioxide adsorbent is prepared by: In step (2), the drying time is 8-24 h.

19. The method for preparing the carbon dioxide adsorbent according to claim 3, characterized in that: In step (2), the calcining conditions are as follows: the calcining temperature is 100-400°C, and the calcining time is 3-10 h.

20. The method for preparing the carbon dioxide adsorbent according to claim 3, characterized in that: In step (2), the calcining conditions are as follows: the calcining temperature is 150-350°C, and the calcining time is 4-8 h.

21. The method of claim 3, wherein the carbon dioxide adsorbent is prepared by: In step (2), the calcining conditions are as follows: the calcining temperature is 200-300°C.

22. A carbon dioxide adsorbent obtained by the method according to any one of claims 3-21.

23. Use of the carbon dioxide adsorbent of any one of claims 1, 2, 22 for absorbing carbon dioxide.