Nonmetal-doped transition metal-coated biomass porous carbon sphere photothermal conversion material, integrated CO2 photothermal continuous trapping system and method

Abstract

The invention provides a non-metal-doped transition metal-coated biomass porous carbon sphere photothermal conversion material and an integrated CO2 photothermal continuous trapping system and method, and belongs to the technical field of CO2 trapping. According to the invention, biomass porous carbon spheres are used as a catalytic functional unit, the carbon spheres have good absorption and conversion capability on solar spectrum, and transition metal is coated on the basis, so that the light absorption capability and the photothermal conversion capability are further enhanced; by introducing P, S and N non-metallic elements for doping, the crystal configuration of the original material can be changed, the energy band structure of the material can be adjusted, the light absorption capacity and the photothermal conversion capacity of the material are further improved, the carbon-based material is applied to alcohol amine solution CO2 trapping equipment, the mass transfer process of absorption liquid in the absorption process can be accelerated, and in the desorption process, the absorption efficiency is improved. Light energy can be converted into heat energy by means of the photo-thermal conversion effect, energy exchange is conducted between the heat energy and rich liquid in a local micro area (the surfaces of the doped carbon-coated metal particles), energy is provided for the desorption process of CO2, and therefore CO2 desorption heat absorption is compensated, and energy consumption is further reduced.

Description

Technical Field

[0001] The present invention relates to the field of CO2 capture technology, and in particular to a non-metal-doped transition metal-coated biomass porous carbon sphere photothermal conversion material, an integrated CO2 photothermal continuous capture system and method. Background Art

[0002] The development of green and efficient CO2 capture and storage (CCS) technology is a research area that is given priority support by science and technology plans.

[0003] The amine solution capture method is currently one of the more mature carbon dioxide capture technologies in coal-fired power plants. It uses amine solution to chemically capture CO2, and then heats the rich liquid to release CO2 to regenerate the absorption liquid. This method has the advantages of high absorption efficiency and fast release, but the traditional chemical absorption-heating desorption strategy still faces the problem of high energy consumption.

[0004] In order to solve the problem of high energy consumption of amine solution capture method, heterogeneous catalysts are currently designed to reduce the heat of CO2 desorption, strengthen mass transfer and catalytic processes, reduce energy consumption, and achieve low-temperature desorption of CO2 at 90°C. At present, the existing heterogeneous catalysts mainly include molecular sieves, zeolites, MOFs materials and metal catalysts, see Xing L, Wei K, Li Y, et al. TiO2 Coating Strategy for Robust Catalysis of the Metal-Organic Framework toward Energy-Efficient CO2 Capture. Environmental Science & Technology 2021, 55, 11216-11224 and Zhang X, Huang Y, Gao H, et al. Zeolite catalyst-aided tri-solvent blend amine regeneration: An alternative pathway to reduce the energy consumption inamine-based CO2 capture process [J]. Applied energy, 2019, 240: 827-841.

[0005] However, how to further reduce the desorption temperature, solve the excessive dependence on external heat source - superheated steam, and reduce equipment corrosion and thermal degradation of the absorption liquid are issues to be addressed in this field. In addition, most of the current heterogeneous catalytic desorption systems are limited by the difficulty in accelerating the CO2 absorption process, and the system's lean liquid-rich liquid cycle process involves a complex catalyst preparation process, which limits its large-scale application. Summary of the invention

[0006] In view of this, the purpose of the present invention is to provide a non-metal-doped transition metal-coated biomass porous carbon sphere photothermal conversion material, an integrated CO2 photothermal continuous capture system and method. The non-metal-doped transition metal-coated biomass porous carbon sphere photothermal conversion material provided by the present invention has a good catalytic effect on CO2 absorption and desorption, realizes the integrated process of CO2 absorption and desorption, and can use light energy to compensate for desorption heat, further reduce the desorption temperature, and reduce energy consumption.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] The present invention provides a method for preparing a non-metal-doped transition metal-coated biomass porous carbon sphere photothermal conversion material, comprising the following steps:

[0009] Mixing a transition metal source, a sugar carbon source, water and ethanol to obtain a mixed solution; the transition metal in the transition metal source includes one or more of Cu, Fe, Ni and Ti;

[0010] The mixed solution is subjected to a hydrothermal reaction to obtain a carbon sphere precursor of a coated transition metal after solid-liquid separation;

[0011] In an Ar-H2 atmosphere, the carbon sphere precursor of the coated transition metal is subjected to a first calcination to obtain a porous carbon sphere precursor of the coated transition metal;

[0012] Placing a non-metallic doping agent at the front end of a tube furnace, placing the porous carbon sphere precursor of the coated transition metal at the rear end of the tube furnace, and calcining the non-metallic doping agent and the porous carbon sphere precursor of the coated transition metal for a second time in an Ar-H2 atmosphere to obtain a non-metallic doped transition metal coated biomass porous carbon sphere photothermal conversion material;

[0013] The non-metallic element in the non-metallic doping agent includes one or more of S, P and N.

[0014] Preferably, the transition metal source includes one or more of copper acetate, nickel nitrate, iron nitrate and titanium tetrachloride;

[0015] The sugar carbon source includes one or more of glucose, fructose and sucrose;

[0016] The mass ratio of the transition metal source to the sugar carbon source is 0.5 to 2:9.

[0017] Preferably, the volume ratio of water to ethanol is 8:1-3;

[0018] The temperature of the hydrothermal reaction is 140-220° C. and the time is 6-18 hours.

[0019] Preferably, in the Ar-H2 atmosphere, the volume percentage of H2 is 1 to 10%;

[0020] The temperature of the first calcination is 250-800° C., and the insulation time is 2-6 hours.

[0021] Preferably, the non-metallic doping agent includes one or more of red phosphorus, urea and sulfur;

[0022] The mass ratio of the sugar carbon source to the non-metallic doping agent is 4.5:1-3;

[0023] During the second calcination, the temperature at the front end of the tubular furnace is 500-600°C, and the temperature at the rear end of the tubular furnace is 300-400°C;

[0024] The holding time of the second calcination is 2 to 8 hours.

[0025] The present invention provides a non-metal-doped transition metal-coated biomass porous carbon sphere photothermal conversion material prepared by the above-mentioned preparation method, the chemical composition of which includes MCX, wherein M represents a transition metal, including one or more of Cu, Fe, Ni and Ti; C represents a porous carbon sphere; and X represents a non-metal element, including one or more of S, P and N.

[0026] The present invention provides the use of the above-mentioned non-metal-doped transition metal-coated biomass porous carbon sphere photothermal conversion material in the absorption and desorption of carbon dioxide by an alcohol amine solution.

[0027] The present invention provides an integrated CO2 photothermal continuous capture system, comprising a plurality of photothermal absorption / desorption towers connected in parallel, wherein a single photothermal absorption / desorption tower is provided with a flue gas inlet, a flue gas outlet and a CO2 outlet;

[0028] A single photothermal absorption / desorption tower is built with an alcoholamine absorption solution and a non-metal-doped transition metal-coated biomass porous carbon ball photothermal conversion material.

[0029] Preferably, a single photothermal absorption / desorption tower is connected to a heater and a cooler;

[0030] A single photothermal absorption / desorption tower has a built-in light source or is exposed to an external light source.

[0031] The present invention provides a method for CO2 photothermal capture based on the above-mentioned integrated CO2 photothermal continuous capture system, wherein the first photothermal absorption / desorption tower and the second photothermal absorption / desorption tower of the integrated CO2 photothermal continuous capture system alternately perform a heating absorption of CO2 and a photothermal catalytic desorption process of CO2, comprising the following steps:

[0032] Open the flue gas inlet of the first photothermal absorption / desorption tower, pass the flue gas containing CO2 into the first photothermal absorption / desorption tower, and heat and absorb CO2. When CO2 is absorbed saturated, close the flue gas inlet of the first photothermal absorption / desorption tower, open the flue gas inlet of the second photothermal absorption / desorption tower, pass the flue gas containing CO2 into the second photothermal absorption / desorption tower, and continue to heat and absorb CO2.

[0033] While the second photothermal absorption / desorption tower is heating and absorbing CO2, the embedded light source of the first photothermal absorption / desorption tower is turned on, or the first photothermal absorption / desorption tower is exposed to an external light source to perform photothermal catalytic desorption of CO2, and the captured CO2 is discharged through the CO2 outlet.

[0034] The present invention provides a method for preparing a non-metal-doped transition metal-coated biomass porous carbon sphere photothermal conversion material, comprising the following steps: mixing a transition metal source, a sugar carbon source, water and ethanol to obtain a mixed solution; the transition metal in the transition metal source comprises one or more of Cu, Fe, Ni and Ti; subjecting the mixed solution to a hydrothermal reaction, and obtaining a carbon sphere precursor of the coated transition metal after solid-liquid separation; and calcining the carbon sphere precursor of the coated transition metal for the first time in an Ar-H2 atmosphere. , obtain a porous carbon sphere precursor coated with transition metal; place a non-metallic doping agent at the front end of a tube furnace, place the porous carbon sphere precursor coated with transition metal at the rear end of the tube furnace, and calcine the non-metallic doping agent and the porous carbon sphere precursor coated with transition metal for a second time in an Ar-H2 atmosphere to obtain a non-metallic doped transition metal coated biomass porous carbon sphere photothermal conversion material (abbreviated as MCX); the non-metallic element in the non-metallic doping agent includes one or more of S, P and N. The present invention uses biomass porous carbon spheres as catalytic functional primitives, and the carbon spheres themselves have good absorption and conversion capabilities for a wide range of solar spectra. On this basis, transition metals are coated to further enhance the light absorption capacity and photothermal conversion capacity; by introducing P, S, and N non-metallic element doping, the original carbon material and metal material crystal configuration can be changed, the energy band structure of the material can be adjusted, and the light absorption capacity and photothermal conversion capacity of the material can be further improved. The transition metal-coated biomass porous carbon ball photothermal conversion material provided by the present invention is applied to the alcohol amine solution CO2 capture equipment, which can accelerate the mass transfer process of the absorption liquid in the absorption process. In the desorption process, the carbon ball material can use the photothermal conversion effect to convert light energy into heat energy, and exchange energy with the rich liquid in the local micro-region (such as the internal pores or surface pores of the carbon ball material) to provide energy for the release of CO2, thereby compensating for the CO2 desorption heat and further reducing energy consumption. Finally, the desorption rate is improved at a lower desorption temperature (such as 85°C), and to a certain extent, the problems of equipment corrosion or absorption liquid pyrolysis caused by high-temperature desorption are alleviated.

[0035] At the same time, the preparation method provided by the present invention is simple to operate, low in cost, and easy to realize industrial mass production.

[0036] The present invention provides an integrated CO2 photothermal continuous capture system, including a plurality of photothermal absorption / desorption towers connected in parallel, a single photothermal absorption / desorption tower is provided with a flue gas inlet, a flue gas outlet and a CO2 outlet; a single photothermal absorption / desorption tower is built with an alcohol amine absorption solution and a non-metal-doped transition metal-coated biomass porous carbon sphere photothermal conversion material. The present invention constructs an integrated recyclable CO2 continuous capture and desorption system by means of an embedded light source or external natural light conditions, and adds the above-mentioned non-metal-doped transition metal-coated biomass porous carbon sphere photothermal conversion material to the solution in the photothermal absorption / desorption tower to promote the absorption / desorption process. The first photothermal absorption / desorption tower and the second photothermal absorption / desorption tower of the integrated CO2 photothermal continuous capture system can alternately perform the heating absorption of CO2 and the photothermal catalytic desorption process of CO2, thereby realizing the continuous capture and release of CO2, improving the capture efficiency and reducing energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic diagram of the structure of an integrated CO2 photothermal continuous capture system;

[0038] Figure 2 Schematic diagram of the integrated CO2 photothermal continuous capture system with built-in light source and contact with external light source;

[0039] Figure 3 This is the SEM image of the Cu-CP obtained in Example 1;

[0040] Figure 4 TEM image of Cu-CP obtained in Example 1;

[0041] Figure 5 XRD diagrams of the biomass porous carbon sphere photothermal conversion materials obtained in Examples 1 to 3 and Comparative Example 1;

[0042] Figure 6 The results of the absorption of CO2 in the alcohol amine solution by the materials obtained in Examples 1 to 6 and Comparative Examples 1 to 2;

[0043] Figure 7 The results are the desorption amounts of CO2 in the alcohol amine solution by the materials obtained in Examples 1 to 6 and Comparative Examples 1 to 2.

[0044] Figure 8 This is the regeneration energy consumption diagram of the Cu-CP material obtained in Example 1 for the alcoholamine solution. DETAILED DESCRIPTION

[0045] The present invention provides a method for preparing a non-metal-doped transition metal-coated biomass porous carbon sphere photothermal conversion material, comprising the following steps:

[0046] Mixing a transition metal source, a sugar carbon source, water and ethanol to obtain a mixed solution; the transition metal in the transition metal source includes one or more of Cu, Fe, Ni and Ti;

[0047] The mixed solution is subjected to a hydrothermal reaction to obtain a carbon sphere precursor of a coated transition metal after solid-liquid separation;

[0048] In an Ar-H2 atmosphere, the carbon sphere precursor of the coated transition metal is subjected to a first calcination to obtain a porous carbon sphere precursor of the coated transition metal;

[0049] Placing a non-metallic doping agent at the front end of a tube furnace, placing the porous carbon sphere precursor of the coated transition metal at the rear end of the tube furnace, and calcining the non-metallic doping agent and the porous carbon sphere precursor of the coated transition metal for a second time in an Ar-H2 atmosphere to obtain a non-metallic doped transition metal coated biomass porous carbon sphere photothermal conversion material;

[0050] The non-metallic element in the non-metallic doping agent includes one or more of S, P and N.

[0051] The present invention mixes a transition metal source, a sugar carbon source, water and ethanol to obtain a mixed solution. In the present invention, the transition metal in the transition metal source includes one or more of Cu, Fe, Ni and Ti; in the present invention, the transition metal source preferably includes one or more of copper acetate, nickel nitrate, iron nitrate and titanium tetrachloride.

[0052] In the present invention, the carbohydrate carbon source preferably includes one or more of glucose, fructose and sucrose; the mass ratio of the transition metal source to the carbohydrate carbon source is preferably 0.5 to 2:9, more preferably 1:9.

[0053] In the present invention, the water is preferably deionized water, and the volume ratio of water to ethanol is preferably 8:1 to 3. In the present invention, the volume ratio of the mass of the carbohydrate carbon source to water is preferably 3 to 6 g:60 to 90 mL, more preferably 4.5 g:80 mL.

[0054] In the present invention, the mixing method is preferably stirring and / or ultrasonic mixing.

[0055] The present invention conducts a hydrothermal reaction on the mixed solution, and obtains a carbon sphere precursor of a coated transition metal after solid-liquid separation. In the present invention, the hydrothermal reaction is preferably carried out in a hydrothermal kettle, the temperature of the hydrothermal reaction is preferably 140 to 220° C., more preferably 160 to 200° C., and the time is preferably 6 to 18 hours, more preferably 8 to 12 hours.

[0056] In the present invention, the solid-liquid separation is preferably centrifugal; in the present invention, the centrifugal speed is preferably 8000-10000 r / min, more preferably 10000 r / min, and the time is preferably 10-15 min, more preferably 10 min.

[0057] In the present invention, after the solid-liquid separation, the present invention preferably removes the supernatant, washes, dries and grinds the obtained solid. In the present invention, the washing method is preferably centrifugal washing, and the washing liquid used for the washing is preferably a mixture of alcohol and water, and the volume ratio of the alcohol to water is preferably 1:1; in the present invention, the alcohol is preferably ethanol. The present invention performs the centrifugal washing until the supernatant is clear. In the present invention, the drying is preferably carried out in an oven, and the drying temperature is preferably 80°C and the time is preferably 6h. The present invention has no special requirements for the grinding method, and the grinding method familiar to those skilled in the art can be used.

[0058] After obtaining the carbon sphere precursor of the coated transition metal, the present invention performs a first calcination on the carbon sphere precursor of the coated transition metal in an Ar-H2 atmosphere to obtain a porous carbon sphere precursor of the coated transition metal. In the present invention, the volume percentage of H2 in the Ar-H2 atmosphere is preferably 1-10%, and more preferably 3-7%. In the present invention, the first calcination is preferably carried out in a tube furnace, and the temperature of the first calcination is preferably 250-800°C, and more preferably 400-600°C; the insulation time is preferably 2-6h, and more preferably 3-5h. In the present invention, the heating rate from room temperature to the first calcination temperature is preferably 5°C / min. Through the first calcination, the present invention gives the carbon sphere a porous structure and reduces the transition metal to a metal element.

[0059] After obtaining the porous carbon sphere precursor of the coated transition metal, the present invention places the non-metallic doping agent at the front end of the tube furnace, places the porous carbon sphere precursor of the coated transition metal at the rear end of the tube furnace, and performs a second calcination on the non-metallic doping agent and the porous carbon sphere precursor of the coated transition metal in an Ar-H2 atmosphere to obtain a biomass porous carbon sphere photothermal conversion material of the coated transition metal. In the present invention, the non-metallic doping agent preferably includes one or more of red phosphorus, urea and sulfur; the mass ratio of the carbohydrate carbon source to the non-metallic doping agent is preferably 4.5:1 to 3, more preferably 4.5:2.

[0060] In the present invention, the volume percentage of H2 in the Ar-H2 atmosphere is preferably 1 to 10%, more preferably 3 to 7%.

[0061] In the present invention, during the second calcination, the temperature at the front end of the tube furnace is preferably 500-600°C, and the temperature at the rear end of the tube furnace is preferably 300-400°C; the insulation time of the second calcination is preferably 2-6h, more preferably 3-5h. In the present invention, the heating rate of the second calcination is preferably 5°C / min. The present invention adopts a method of calcining the non-metallic doping reagent and the porous carbon sphere precursor of the coated transition metal separately, and utilizes the higher temperature at the front end to first convert the non-metallic doping reagent into a gaseous state, and is entrained by the airflow to the rear end to react with the porous carbon sphere precursor of the coated transition metal, thereby ensuring sufficient contact and reaction of the non-metallic doping reagent.

[0062] The present invention provides a non-metal-doped transition metal-coated biomass porous carbon sphere photothermal conversion material prepared by the above-mentioned preparation method, the chemical composition of which is expressed as MCX, wherein M represents a transition metal, including one or more of Cu, Fe, Ni and Ti; C represents a porous carbon sphere; and X represents a non-metal element, including one or more of S, P and N.

[0063] In the present invention, in the non-metal doped transition metal-coated biomass porous carbon sphere photothermal conversion material, the mass content of the transition metal is preferably 1-3%, more preferably 1.5-2.5%; the mass content of the non-metallic element is preferably 2-7%, more preferably 3-5%; the remainder is porous carbon spheres.

[0064] In the present invention, the particle size of the non-metal doped transition metal-coated biomass porous carbon sphere photothermal conversion material is preferably 100-600nm, more preferably 200-500nm; the pore size is preferably 0.7-15nm, more preferably 2-10nm. In the present invention, the specific surface area of ​​the non-metal doped transition metal-coated biomass porous carbon sphere photothermal conversion material is preferably 200-800m 2 ·g -1 , more preferably 400 to 600 m 2 ·g -1 ; The pore volume is preferably 0.10 to 0.15 cm 3 ·g -1 , more preferably 0.12 to 0.14 cm 3 ·g -1 .

[0065] The present invention provides the use of the above-mentioned non-metal-doped transition metal-coated biomass porous carbon sphere photothermal conversion material in the absorption and desorption of carbon dioxide by an alcohol amine solution.

[0066] The present invention provides an integrated CO2 photothermal continuous capture system, comprising a plurality of photothermal absorption / desorption towers connected in parallel, wherein a single photothermal absorption / desorption tower is provided with a flue gas inlet, a flue gas outlet and a CO2 outlet;

[0067] A single photothermal absorption / desorption tower is built with a mixture of an alcohol amine absorption solution and a non-metal-doped transition metal-coated biomass porous carbon ball photothermal conversion material.

[0068] In the present invention, the number of the photothermal absorption / desorption towers is preferably 2 to 3; in the present invention, when the number of the photothermal absorption / desorption towers is 2, the two photothermal absorption / desorption towers alternately perform the heating absorption of CO2 and the photothermal catalytic desorption process of CO2; when the number of the photothermal absorption / desorption towers is 3, another photothermal absorption / desorption tower is supplemented according to actual working conditions.

[0069] The present invention has no special requirements on the locations of the smoke inlet, smoke outlet and CO2 outlet, and they can be designed accordingly according to actual working conditions.

[0070] In the present invention, the alcoholamine is preferably ethanolamine.

[0071] In the present invention, the mass fraction of the alcoholamine in the alcoholamine absorption solution is preferably 30%; the mass content of the non-metal doped transition metal-coated biomass porous carbon ball photothermal conversion material in the alcoholamine absorption solution is preferably 0.0375-0.1wt%, more preferably 0.075wt%.

[0072] In the present invention, the single photothermal absorption / desorption tower is preferably connected to a heater and a cooler. The present invention has no special requirements for the specific types of the heater and the cooler, and a heater or cooler familiar to those skilled in the art can be used. In the present invention, the photothermal absorption / desorption tower is embedded with a light source or is in contact with an external light source. In the present invention, the light intensity of the embedded light source is preferably natural light intensity, and the wavelength is preferably full spectrum.

[0073] In the present invention, when the photothermal absorption / desorption tower contacts an external light source, the construction material of the photothermal absorption / desorption tower is a transparent material. In the present invention, the external light source is preferably natural light.

[0074] In the present invention, the structural schematic diagram of the integrated CO2 photothermal continuous capture system is as follows Figure 1 As shown, the schematic diagram of the integrated CO2 photothermal continuous capture system with an embedded light source and contact with an external light source is as shown in Figure 2 As a specific embodiment of the present invention, this design scenario is suitable for a small boiler.

[0075] The present invention provides a method for CO2 photothermal capture based on the above-mentioned integrated CO2 photothermal continuous capture system, wherein the first photothermal absorption / desorption tower and the second photothermal absorption / desorption tower of the integrated CO2 photothermal continuous capture system alternately perform a heating absorption of CO2 and a photothermal catalytic desorption process of CO2, comprising the following steps:

[0076] Open the flue gas inlet of the first photothermal absorption / desorption tower, pass the flue gas containing CO2 into the first photothermal absorption / desorption tower, and heat and absorb CO2. When CO2 is absorbed saturated, close the flue gas inlet of the first photothermal absorption / desorption tower, open the flue gas inlet of the second photothermal absorption / desorption tower, pass the flue gas containing CO2 into the second photothermal absorption / desorption tower, and continue to heat and absorb CO2.

[0077] While the second photothermal absorption / desorption tower is heating and absorbing CO2, the embedded light source of the first photothermal absorption / desorption tower is turned on, or the first photothermal absorption / desorption tower is exposed to an external light source to perform photothermal catalytic desorption of CO2, and the captured CO2 is discharged through the CO2 outlet.

[0078] In the present invention, the flue gas containing CO2 preferably contains 10-15% CO2, preferably 12-14% CO2, in terms of volume percentage. As a specific embodiment of the present invention, the remaining component of the flue gas containing CO2 is preferably N2.

[0079] In the present invention, the flow rate of the flue gas containing CO2 is preferably 100 to 200 sccm, more preferably 150 sccm.

[0080] In the present invention, the temperature of the heated absorption of CO2 is preferably 40-50°C, more preferably 45°C; the time is preferably 90-150 min, more preferably 100-130 min.

[0081] In the present invention, the temperature of the photothermal catalytic desorption of CO2 is preferably 85 to 95°C, more preferably 90°C; the time is preferably 30 to 60 min, more preferably 40 to 50 min.

[0082] The following is a detailed description of a non-metal-doped transition metal-coated biomass porous carbon ball photothermal conversion material, an integrated CO2 photothermal continuous capture system and method provided by the present invention in conjunction with the embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0083] Example 1

[0084] The preparation method of non-metal-doped transition metal-coated biomass porous carbon sphere photothermal conversion material Cu-CP adopts the following steps:

[0085] ① Weigh 0.5g of copper acetate and 4.5g of glucose, then dissolve them in a mixture of 80mL of deionized water and 10mL of ethanol, and dissolve them into a uniform blue-green solution by stirring and ultrasonication;

[0086] ② Add the water-heated kettle and place it in a drying oven and heat at 180℃ for 8h;

[0087] ③ After cooling down, the solution was placed in a centrifuge and centrifuged for 10 minutes at a speed of 10000r / min, and then the supernatant was removed, and the drug was repeatedly washed with a solution of alcohol and water mixed in a ratio of 1:1, and centrifuged until the supernatant was clear; the obtained solid was placed in an oven, dried at 80°C for 6 hours, and the carbon sphere precursor of the coated transition metal was obtained after grinding;

[0088] ④ After the Ar-H2 is introduced, the ground copper-coated carbon sphere precursor is placed in a tube furnace and calcined at 550°C for 2 hours to form porous carbon spheres coated with copper;

[0089] ⑤ After introducing Ar-H2, place 1g of red phosphorus in the front temperature zone of the tubular furnace and set the temperature to 600℃. Place the calcined carbon balls in the rear temperature zone and set the temperature to 400℃. Keep warm for 2h to obtain the biomass porous carbon ball photothermal conversion material Cu-CP coated with transition metal.

[0090] The SEM image of the obtained Cu-CP is shown in Figure 3 As shown by Figure 3 It can be seen that the synthesized material has a carbon sphere structure, good dispersibility, and a particle size range of 300 to 500 nm.

[0091] The TEM image of the obtained Cu-CP is shown in Figure 4 As shown by Figure 4 It can be seen that the synthesized material has no crystal lattice.

[0092] Example 2

[0093] The preparation method of non-metal-doped transition metal-coated biomass porous carbon sphere photothermal conversion material Cu-CS adopts the following steps:

[0094] ① Weigh 0.5g of copper acetate and 4.5g of glucose, then dissolve them in a mixture of 80mL of deionized water and 10mL of ethanol, and dissolve them into a uniform blue-green solution by stirring and ultrasonication;

[0095] ② Add the water-heated kettle and place it in a drying oven and heat at 180℃ for 8h;

[0096] ③ After cooling down, the solution was placed in a centrifuge and centrifuged for 10 minutes at a speed of 10000r / min, and then the supernatant was removed, and the drug was repeatedly washed with a solution of alcohol and water mixed in a ratio of 1:1, and centrifuged until the supernatant was clear; the obtained solid was placed in an oven, dried at 80°C for 6 hours, and the carbon sphere precursor of the coated transition metal was obtained after grinding;

[0097] ④ After the Ar-H2 is introduced, the ground copper-coated carbon sphere precursor is placed in a tube furnace and calcined at 550°C for 2 hours to form porous carbon spheres coated with copper;

[0098] ⑤ After introducing Ar-H2, place 1g of sulfur in the front temperature zone of the tubular furnace and set the temperature to 600℃. Place the calcined carbon balls in the rear temperature zone and set the temperature to 400℃. Keep warm for 2h to obtain the transition metal-coated biomass porous carbon ball photothermal conversion material Cu-CS.

[0099] Example 3

[0100] The preparation method of non-metal-doped transition metal-coated biomass porous carbon sphere photothermal conversion material Cu-CN adopts the following steps:

[0101] ① Weigh 0.5g of copper acetate and 4.5g of glucose, then dissolve them in a mixture of 80mL of deionized water and 10mL of ethanol, and dissolve them into a uniform blue-green solution by stirring and ultrasonication;

[0102] ② Add the water-heated kettle and place it in a drying oven and heat at 180℃ for 8h;

[0103] ③ After cooling down, the solution was placed in a centrifuge and centrifuged for 10 minutes at a speed of 10000r / min, and then the supernatant was removed, and the drug was repeatedly washed with a solution of alcohol and water mixed in a ratio of 1:1, and centrifuged until the supernatant was clear; the obtained solid was placed in an oven, dried at 80°C for 6 hours, and the transition metal-coated carbon sphere precursor was obtained after grinding;

[0104] ④ After the Ar-H2 is introduced, the ground copper-coated carbon sphere precursor is placed in a tube furnace and calcined at 550°C for 2 hours to form copper-coated porous carbon spheres;

[0105] ⑤ After introducing Ar-H2, place 1g of urea in the front temperature zone of the tubular furnace and set the temperature to 600℃. Place the calcined carbon balls in the rear temperature zone and set the temperature to 400℃. Keep warm for 2h to obtain the transition metal-coated biomass porous carbon ball photothermal conversion material Cu-CN.

[0106] Comparative Example 1

[0107] The difference from Example 1 is that red phosphorus is not added in step ⑤, and the transition metal-coated biomass porous carbon ball photothermal conversion material Cu-C is obtained.

[0108] The XRD patterns of the biomass porous carbon sphere photothermal conversion materials obtained in Examples 1 to 3 and Comparative Example 1 are shown in Figure 5 As shown. Figure 5 It can be seen that the carbon ball has a certain copper characteristic peak after being coated with metallic copper. With the doping of N, S, and P elements, the crystal structure of the material changes, the characteristic peak of copper disappears, and it changes from crystalline copper to disordered copper. Figure 4 The TEM image also shows that there is no obvious crystalline structure inside the P-doped material.

[0109] Comparative Example 2

[0110] The difference from Example 1 is that copper acetate is not added in step ①, and red phosphorus is not added in step ⑤, and biomass porous carbon balls C are obtained.

[0111] Example 4

[0112] The preparation method of non-metal-doped transition metal-coated biomass porous carbon sphere photothermal conversion material Fe-CP adopts the following steps:

[0113] ① Weigh 0.5g ferric nitrate and 4.5g glucose, then dissolve them in a mixture of 80mL deionized water and 10mL ethanol, and dissolve them into a uniform solution by stirring and ultrasonication;

[0114] ② Add the water-heated kettle and place it in a drying oven and heat at 180℃ for 8h;

[0115] ③ After cooling down, the solution was placed in a centrifuge and centrifuged for 10 minutes at a speed of 10000r / min, and then the supernatant was removed, and the drug was repeatedly washed with a solution of alcohol and water mixed in a ratio of 1:1, and centrifuged until the supernatant was clear; the obtained solid was placed in an oven, dried at 80°C for 6 hours, and the transition metal-coated carbon sphere precursor was obtained after grinding;

[0116] ④ After introducing Ar-H2, the ground iron-coated carbon sphere precursor was placed in a tube furnace and calcined at 550°C for 2h to form porous carbon spheres coated with iron;

[0117] ⑤ After introducing Ar-H2, place 1g of red phosphorus in the front temperature zone of the tubular furnace and set the temperature to 600℃. Place the calcined carbon balls in the rear temperature zone and set the temperature to 400℃. Keep warm for 2h to obtain the transition metal-coated biomass porous carbon ball photothermal conversion material Fe-CP.

[0118] Example 5

[0119] The preparation method of non-metal-doped transition metal-coated biomass porous carbon sphere photothermal conversion material Ni-CP adopts the following steps:

[0120] ① Weigh 0.5g nickel nitrate and 4.5g glucose, then dissolve them in a mixture of 80mL deionized water and 10mL ethanol, and dissolve them into a uniform solution by stirring and ultrasonication;

[0121] ② Add the water-heated kettle and place it in a drying oven and heat at 180℃ for 8h;

[0122] ③ After cooling down, the solution was placed in a centrifuge and centrifuged for 10 minutes at a speed of 10000r / min, and then the supernatant was removed, and the drug was repeatedly washed with a solution of alcohol and water mixed in a ratio of 1:1, and centrifuged until the supernatant was clear; the obtained solid was placed in an oven, dried at 80°C for 6 hours, and the transition metal-coated carbon sphere precursor was obtained after grinding;

[0123] ④ After introducing Ar-H2, the ground nickel-coated carbon sphere precursor was placed in a tube furnace and calcined at 550°C for 2h to form nickel-coated porous carbon spheres;

[0124] ⑤ After introducing Ar-H2, place 1g of red phosphorus in the front temperature zone of the tubular furnace and set the temperature to 600℃. Place the calcined carbon balls in the rear temperature zone and set the temperature to 400℃. Keep warm for 2h to obtain the transition metal-coated biomass porous carbon ball photothermal conversion material Ni-CP.

[0125] Example 6

[0126] The preparation method of non-metal-doped transition metal-coated biomass porous carbon sphere photothermal conversion material Ti-CP adopts the following steps:

[0127] ① Weigh 0.5g titanium tetrachloride and 4.5g glucose, dissolve in a mixture of 80mL deionized water and 10mL ethanol, and dissolve into a uniform solution by stirring and ultrasonication;

[0128] ② Add the water-heated kettle and place it in a drying oven and heat at 180℃ for 8h;

[0129] ③ After cooling down, the solution was placed in a centrifuge and centrifuged for 10 minutes at a speed of 10000r / min, and then the supernatant was removed, and the drug was repeatedly washed with a solution of alcohol and water mixed in a ratio of 1:1, and centrifuged until the supernatant was clear; the obtained solid was placed in an oven, dried at 80°C for 6 hours, and the transition metal-coated carbon sphere precursor was obtained after grinding;

[0130] ④ After the Ar-H2 is introduced, the ground titanium-coated carbon sphere precursor is placed in a tube furnace and calcined at 550°C for 2 hours to form porous carbon spheres coated with titanium;

[0131] ⑤ After introducing Ar-H2, place 1g of red phosphorus in the front temperature zone of the tubular furnace and set the temperature to 600℃. Place the calcined carbon balls in the rear temperature zone and set the temperature to 400℃. Keep warm for 2h to obtain the transition metal-coated biomass porous carbon ball photothermal conversion material Ti-CP.

[0132] Performance Testing

[0133] The absorption and desorption of CO2 in the alcohol amine solution were tested on the materials obtained in Examples 1 to 6 and Comparative Examples 1 to 2, and the method was as follows:

[0134] During the absorption test, the CO2 flow rate at the inlet end was set to 100 sccm, 40 g of 30% ethanolamine solution was loaded into the absorber, the content of the biomass porous carbon ball photothermal conversion material obtained in Examples 1 to 6 and Comparative Examples 1 to 2 was 0.075 wt%, the absorption temperature was 40°C, and the absorption was performed for 1 hour.

[0135] The results of the absorption of CO2 in the alcohol amine solution by the materials obtained in Examples 1 to 6 and Comparative Examples 1 to 2 are as follows: Figure 6 shown. Figure 6 The blank group in the figure represents the CO2 absorption of the blank ethanolamine solution, which is Figure 6 It can be seen that the non-metal-doped transition metal-coated biomass porous carbon ball photothermal conversion material provided by the present invention has a significant effect on improving the absorption of CO2.

[0136] During the desorption process, the ethanolamine solution saturated with the above process was placed under a xenon lamp to simulate light, the temperature was set to 80°C, and the desorption was carried out for 0.5h.

[0137] The results of the desorption of CO2 in the alcohol amine solution by the materials obtained in Examples 1 to 6 and Comparative Examples 1 to 2 are as follows: Figure 7 shown. Figure 7 The blank group in the figure represents the CO2 desorption amount of the blank ethanolamine solution under light conditions, which is Figure 7 It can be seen that under light conditions, the non-metal doped transition metal-coated biomass porous carbon ball photothermal conversion material provided by the present invention has a significant effect on improving the desorption amount of CO2, among which Cu-CP has the best effect on improving the desorption amount of CO2 under light conditions.

[0138] The regeneration energy consumption (i.e., CO2 desorption energy consumption) of the Cu-CP material obtained in Example 1 for the alcohol amine solution is shown in the figure Figure 8 As shown. Figure 8It can be seen that in a set of desorption tests (0.5h), the relative energy consumption in the desorption process was between 11% and 50%, which had a significant effect of reducing energy consumption. Among them, the desorption time reached the lowest relative energy consumption at about 600s. Around this time point, the material had the greatest improvement in desorption rate and the highest energy consumption compensation.

[0139] Application Example 1

[0140] Build as Figure 1 In the integrated CO2 photothermal continuous capture system shown, the mass of the amine absorption solution in a single photothermal absorption / desorption tower is 40 g, the mass fraction of ethanolamine in the amine absorption solution is 30%, and the amine absorption solution contains 0.075 wt% of non-metal-doped transition metal-coated biomass porous carbon ball photothermal conversion material Cu-CP.

[0141] Use the No. 1 photothermal absorption / desorption tower and the No. 2 photothermal absorption / desorption tower to alternately carry out the heating absorption of CO2 and the photothermal catalytic desorption process of CO2. The flue gas is pure CO2 and the flue gas flow rate is 100 sccm. First, the CO2 absorption process of tower No. 1 is carried out for 1 hour at a temperature of 40°C. After the absorption of tower No. 1 is completed, the valve control of tower No. 1 is closed, and the valve control of tower No. 2 is opened to pass the flue gas into the No. 2 photothermal absorption / desorption tower for continuous CO2 absorption for 1 hour at a temperature of 40°C. At the same time, the CO2 rich liquid in tower No. 1 can be desorbed for 1 hour. Heat the solution to 85°C with the heater of tower No. 1, turn on the embedded light source, perform photothermal catalytic desorption on the rich liquid, release CO2, and cool it to 40°C after the desorption process is completed, and then repeat the absorption process.

[0142] According to the test, the outlet flue gas flow rate of a single photothermal absorption / desorption tower is 100sccm, i.e. 100mL / min, the CO2 absorption capacity is 50-100mg / h, and the desorption capacity is 20-40mg / 0.5h.

[0143] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a non-metal-doped transition metal-coated biomass porous carbon sphere photothermal conversion material, comprising the following steps: Mixing a transition metal source, a sugar carbon source, water and ethanol to obtain a mixed solution; the transition metal in the transition metal source includes one or more of Cu, Fe, Ni and Ti; The mixed solution is subjected to a hydrothermal reaction to obtain a carbon sphere precursor of a coated transition metal after solid-liquid separation; In an Ar-H2 atmosphere, the carbon sphere precursor of the coated transition metal is subjected to a first calcination to obtain a porous carbon sphere precursor of the coated transition metal; Placing a non-metallic doping agent at the front end of a tube furnace, placing the porous carbon sphere precursor of the coated transition metal at the rear end of the tube furnace, and calcining the non-metallic doping agent and the porous carbon sphere precursor of the coated transition metal for a second time in an Ar-H2 atmosphere to obtain a non-metallic doped transition metal coated biomass porous carbon sphere photothermal conversion material; The non-metallic element in the non-metallic doping agent includes one or more of S, P and N.

2. The preparation method according to claim 1, characterized in that: The transition metal source includes one or more of copper acetate, nickel nitrate, iron nitrate and titanium tetrachloride; The sugar carbon source includes one or more of glucose, fructose and sucrose; The mass ratio of the transition metal source to the sugar carbon source is 0.5 to 2:

9.

3. The preparation method according to claim 1 or 2, characterized in that: The volume ratio of water to ethanol is 8:1-3; The temperature of the hydrothermal reaction is 140-220° C. and the time is 6-18 hours.

4. The preparation method according to claim 1, characterized in that: In the Ar-H2 atmosphere, the volume percentage of H2 is 1 to 10%; The temperature of the first calcination is 250-800° C., and the insulation time is 2-6 hours.

5. The preparation method according to claim 1, characterized in that: The non-metallic doping agent includes one or more of red phosphorus, urea and sulfur; The mass ratio of the sugar carbon source to the non-metallic doping agent is 4.5:1-3; During the second calcination, the temperature at the front end of the tubular furnace is 500-600°C, and the temperature at the rear end of the tubular furnace is 300-400°C; The holding time of the second calcination is 2 to 8 hours.

6. The non-metal-doped transition metal-coated biomass porous carbon sphere photothermal conversion material prepared by the preparation method according to any one of claims 1 to 5, wherein the chemical composition includes MCX, wherein M represents a transition metal, including one or more of Cu, Fe, Ni and Ti; C represents a porous carbon sphere; and X represents a non-metal element, including one or more of S, P and N.

7. Use of the non-metal-doped transition metal-coated biomass porous carbon sphere photothermal conversion material according to claim 6 in the absorption and desorption of carbon dioxide by an alcohol amine solution.

8. An integrated CO2 photothermal continuous capture system, comprising a plurality of photothermal absorption / desorption towers connected in parallel, wherein a single photothermal absorption / desorption tower is provided with a flue gas inlet, a flue gas outlet and a CO2 outlet; A single photothermal absorption / desorption tower is internally provided with an alcoholamine absorption solution and the non-metal-doped transition metal-coated biomass porous carbon sphere photothermal conversion material according to claim 6.

9. The integrated CO2 photothermal continuous capture system according to claim 8, characterized in that: A single photothermal absorption / desorption tower is connected to a heater and a cooler; A single photothermal absorption / desorption tower has a built-in light source or is exposed to an external light source.

10. A method for CO2 photothermal capture based on the integrated CO2 photothermal continuous capture system according to claim 8 or 9, characterized in that: The first photothermal absorption / desorption tower and the second photothermal absorption / desorption tower of the integrated CO2 photothermal continuous capture system alternately perform a process of heating absorption of CO2 and photothermal catalytic desorption of CO2, including the following steps: Open the flue gas inlet of the first photothermal absorption / desorption tower, pass the flue gas containing CO2 into the first photothermal absorption / desorption tower, and heat and absorb CO2. When CO2 is absorbed saturated, close the flue gas inlet of the first photothermal absorption / desorption tower, open the flue gas inlet of the second photothermal absorption / desorption tower, pass the flue gas containing CO2 into the second photothermal absorption / desorption tower, and continue to heat and absorb CO2. While the second photothermal absorption / desorption tower is heating and absorbing CO2, the embedded light source of the first photothermal absorption / desorption tower is turned on, or the first photothermal absorption / desorption tower is exposed to an external light source to perform photothermal catalytic desorption of CO2, and the captured CO2 is discharged through the CO2 outlet.

Images