Multi-layer thin-wall NiO / stainless steel hollow ball for catalyzing analysis of amine absorbent
By preparing multi-layer thin-walled NiO/stainless steel hollow spheres as catalysts, the problem of high energy consumption of amine-based CO2 chemical absorbers in the desorption process is solved, and the effect of reducing desorption temperature and energy consumption, improving catalytic activity and extending service life is achieved.
Patent Information
- Application Number
- CN202411856715.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-17
- Publication Date
- 2025-03-25
AI Technical Summary
In the prior art, amine-based CO2 chemical absorbers require high temperature and a large amount of energy in the process of desorption of CO2, resulting in high energy consumption and short service life of the absorber.
By preparing multi-layer thin-walled NiO/stainless steel hollow spheres, it is used as a catalyst to increase the contact area between the acidic catalyst and the absorbent, promote the CO2 desorption process, and reduce the desorption temperature and energy consumption.
It effectively reduces the temperature and energy consumption of CO2 desorption, improves catalytic activity, extends the service life of the absorbent, and realizes the recycling of the catalyst.
Smart Images
Figure CN119680549A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of metal oxide catalysts, and in particular relates to a multi-layer thin-wall NiO / stainless steel hollow ball for catalyzing the decomposition of amine absorbents. Background Art
[0002] As a structural and functional integrated material, metal hollow sphere composite materials have the characteristics of low density and high porosity. As a low-density and high specific surface area reinforcement, metal hollow spheres often obtain a porous structure during the sintering process, so they can increase the contact area with the matrix or solution, thereby playing a positive role in the fields of reaction and sound insulation, shielding and heat absorption. In addition to being actively used in acoustics, shielding, damping and other fields, they have also entered the fields of biology, chemistry, energy, environmental protection, etc.
[0003] The preparation methods of metal hollow spheres are generally divided into template removal method and template-free method. In the template removal method, round particles with stable chemical properties under certain conditions are usually used as templates for hollow spheres. A layer of metal powder is wrapped on the template by a certain method to form a blank, and the template is removed by a certain method to obtain metal hollow spheres. In the template removal method, polystyrene is often used as a template for metal hollow spheres because of its low price. In the process of preparing metal hollow spheres, the main method used in the template removal stage is vacuum sintering. In vacuum sintering, the sintering temperature and insulation time are the main factors affecting the ball formation rate, performance and porosity. The advantages of using the template removal method to prepare metal hollow spheres are simple operation, low cost and easy mass production.
[0004] In the carbon dioxide capture device, organic amines are used to absorb carbon dioxide, and then desorb carbon dioxide (amine catalytic regeneration). At this time, steam heating (about 100-120°C) is required. In order to promote the desorption process and reduce the desorption temperature and time, a catalyst needs to be added to speed up the reaction.
[0005] Commonly used amine CO2 chemical absorbents need to be heated to desorb CO2. Taking ethanolamine commonly used in industry as an example, its CO2 absorption reaction rate constant k+ (about 8000L / mol*s) is more than 200 times the CO2 desorption reaction rate constant k- (about 35L / mol*s), which requires a lot of energy to promote amine desorption. At the same time, excessively high temperatures (about 120°C) will accelerate the oxidative degradation and thermal degradation of amines and shorten the service life of amine absorbents. The catalyst for CO2 desorption is a solid acid material, but the solid acid catalyst has a limited contact area with the amine absorbent, which is inconvenient to use and has a high catalytic temperature and a long reaction time.
[0006] The present invention prepares a multi-layer porous thin-wall NiO hollow sphere loaded with an acidic catalyst, which is used as a catalyst after RNH2 absorbs CO2. This can increase the contact path and time between amines and the acidic catalyst, promote the process of CO2 desorption by the amine absorbent, reduce the desorption temperature and desorption energy consumption, and has significant economic value. Summary of the invention
[0007] The purpose of the present invention is to provide a multilayer thin-wall NiO / stainless steel hollow sphere for catalyzing the decomposition of amine absorbents. The multilayer thin-wall NiO / stainless steel hollow sphere is prepared by vacuum sintering NiO powder and stainless steel hollow spheres using stainless steel hollow spheres as templates, thereby increasing the contact area between the acid catalyst and the absorbent; and after the NiO hollow spheres lose activity in a cyclic reaction, the NiO hollow spheres can be recovered through conventional chemical reactions for recycling.
[0008] In order to achieve the above object, the technical solution of the present invention is:
[0009] The invention discloses a multi-layer thin-wall NiO / stainless steel hollow sphere for catalyzing the decomposition of amine absorbents. The catalyst is characterized in that the stainless steel hollow sphere is used as the inner layer structure and template, NiO powder is coated on the surface of the stainless steel hollow sphere by a coating method to obtain a multi-layer hollow sphere embryo; the NiO powder is sintered in a vacuum sintering furnace to form a NiO shell on the outer surface of the stainless steel hollow sphere, thereby obtaining a multi-layer porous thin-wall NiO hollow sphere.
[0010] Preferably, the stainless steel hollow ball is a 316L stainless steel hollow ball.
[0011] Preferably, the diameter of the multi-layer thin-wall NiO / stainless steel hollow sphere is 2-10 mm, wherein the wall thickness of the NiO layer is 10-1000 μm.
[0012] Preferably, the NiO spherical powder is a NiO powder prepared by gas atomization, water atomization or mechanical ball milling, with a particle size not greater than 70 μm and a spherical or irregular shape.
[0013] The preparation method of a multi-layer thin-wall NiO / stainless steel hollow sphere for catalytic amine absorbent decomposition of the present invention comprises the following steps: using the stainless steel hollow sphere as the inner layer structure and template, spraying metal oxide powder and mist binder solution on the surface of the stainless steel hollow sphere, coating the metal oxide powder on the surface of the stainless steel hollow sphere, and naturally drying to obtain a multi-layer hollow sphere embryo; sintering the multi-layer hollow sphere embryo and removing the binder.
[0014] More specifically, the method for preparing a multi-layer thin-walled NiO / stainless steel hollow sphere with catalytic amine absorbent desorption described in the present invention comprises the following steps: (1) placing the stainless steel hollow sphere in NiO spherical powder and rolling it, and spraying a mist binder solution therein at the same time, so that the NiO spherical powder is bonded and coated on the surface of the stainless steel hollow sphere; (2) naturally drying after coating to obtain a multi-layer hollow sphere embryo; (3) placing the multi-layer hollow sphere embryo in an argon-protected vacuum sintering furnace for sintering to obtain the multi-layer thin-walled NiO / stainless steel hollow sphere.
[0015] Preferably, the step (1) is: placing the stainless steel hollow ball into a rolling device of an automatic coating machine and adding NiO powder thereto; after starting the rolling, using the nozzle device of the automatic coating machine to spray a mist binder solution onto the surface of the stainless steel hollow ball, so that the NiO powder is bonded and coated on the surface of the stainless steel hollow ball.
[0016] Preferably, the mist binder solution is a polyvinyl alcohol aqueous solution with a mass concentration of 2% to 6%, and the spraying amount thereof is 1 / 10 to 1 / 8 of the mass of the NiO powder.
[0017] Preferably, the rotation speed of the automatic coating machine is 30 to 200 r / min, and the coating time is 10 to 60 min.
[0018] Preferably, the drying temperature in step (2) is 10-50° C. (preferably 25-35° C.), and the drying time is 30-120 min.
[0019] In order to ensure that NiO does not react with other impurity gases (CO2, O2) as much as possible under high temperature environment, in the step (3), the multilayer hollow spherical embryo is placed in a vacuum sintering furnace at room temperature and the furnace door is closed; the vacuum pump is turned on and when the vacuum degree reaches 10 -2 The vacuum sintering furnace is filled with argon; the argon is continuously passed and the temperature is raised to 330-400°C (preferably 330-360°C, for example 350°C) at a rate of 1.5-2.5°C / min, kept at this temperature for 20-50min, and the binder is removed; the temperature is then raised to 1100-1200°C at a rate of 10-15°C / min and kept at this temperature for 100-150min; and the multilayer thin-walled NiO / stainless steel hollow spheres are obtained after cooling in the furnace.
[0020] Compared with the prior art, the present invention has the following beneficial effects:
[0021] The multilayer thin-walled NiO / stainless steel hollow sphere prepared by the automatic coating method of the present invention has the characteristics of low manufacturing cost and strong operability, has certain designability, and can realize mass production; the outer layer of NiO and the inner layer of stainless steel are metallurgically bonded by high-temperature sintering, and when reduced by conventional chemical reactions, the interface bonding does not crack, ensuring that the NiO catalytic product and the stainless steel hollow sphere will not fall off, so that the catalyst can be recycled. Compared with the single-layer metal hollow sphere, the stainless steel shell can effectively improve the strength of the NiO hollow sphere, so that the deformation behavior of the hollow sphere under different stress states changes from brittle fracture to plastic fracture; while providing support, the stainless steel can also generate Fe-Ni series compounds with NiO to further enhance the catalytic effect. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 The schematic diagram of the structure of the multi-layer thin-wall NiO / stainless steel hollow sphere of the present invention, wherein: 1 is a 316L stainless steel hollow sphere; 2 is a NiO shell layer.
[0023] Figure 2 This is the macroscopic morphology of the multilayer thin-walled NiO / stainless steel hollow sphere of Example 1.
[0024] Figure 3 This is the SEM image of the multilayer thin-walled NiO / stainless steel hollow sphere of Example 1. DETAILED DESCRIPTION
[0025] Those skilled in the art should recognize that the present embodiment is only used to illustrate the present invention, and is not used to limit the present invention. Any changes or modifications to the embodiment within the scope of the present invention are within the scope of the claims of the present invention.
[0026] Example 1
[0027] A multilayer thin-walled NiO / stainless steel hollow sphere for catalyzing the decomposition of amine absorbents, the preparation method comprising the following steps:
[0028] S1, placing 316L stainless steel hollow balls with an average diameter of 3 mm into a rolling device of an automatic coating machine, adding NiO spherical powder with a particle size of 40 to 65 μm thereto; turning on the rolling device; adjusting the rotation speed of the rolling device to 200 r / min; using a polyvinyl alcohol aqueous solution with a concentration of 4.5% as a binder, and the amount of the binder is 1 / 10 of the mass of the NiO spherical powder; at the same time, spraying the atomized binder solution into the rolling device through a nozzle device, and the coating time is 15 minutes; after the coating is completed, taking out the blank, and naturally air-drying it at a room temperature of 30 to 35° C., and the drying time is 90 minutes, to obtain a multi-layer hollow ball blank;
[0029] S2, put the multilayer hollow spherical embryo into a white alumina crucible, and then put it into a vacuum sintering furnace at room temperature; after closing the sintering furnace door, turn on the vacuum pump to draw vacuum for 90 minutes to ensure that the vacuum degree of the sintering furnace is 10 -2 After that, argon gas is introduced into the vacuum sintering furnace. When the vacuum degree is reduced to 0, the exhaust switch is turned on. When Ar gas is detected at the exhaust port, heating is started; the temperature is raised to 350°C at a rate of 2°C / min and kept for 30 minutes. At this time, the binder is gasified and volatilized; the temperature is then raised to 1350°C at a rate of 10°C / min and kept for 120 minutes. At this time, the NiO spherical powder is metallurgically combined with the 316L stainless steel forming; then the exhaust valve is closed, the Ar gas is turned off and the furnace is cooled to room temperature to obtain multi-layer thin-walled NiO / 316L hollow spheres. After testing, the outer diameter of the multi-layer thin-walled NiO / 316L hollow spheres is 3.5-4 mm, and the wall thickness of the NiO layer is 500-1000 μm.
[0030] Example 2
[0031] A multilayer thin-walled NiO / stainless steel hollow sphere for catalyzing the decomposition of amine absorbents, the preparation method comprising the following steps:
[0032] S1, placing 316L stainless steel hollow balls with an average diameter of 5 mm into a rolling device of an automatic coating machine, adding NiO spherical powder with a particle size of 40 to 65 μm thereto; turning on the rolling device; adjusting the rotation speed of the rolling device to 300 r / min; using a polyvinyl alcohol aqueous solution with a concentration of 5.8% as a binder, and the amount of the binder is 1 / 9 of the mass of the NiO spherical powder; at the same time, spraying the atomized binder solution into the rolling device through a nozzle device, and the coating time is 10 minutes; after the coating is completed, taking out the blank, and naturally air-drying it at a room temperature of 30 to 35° C., and the drying time is 90 minutes, to obtain a multi-layer hollow ball blank;
[0033] S2, put the multilayer hollow spherical embryo into a white alumina crucible, and then put it into a vacuum sintering furnace at room temperature; after closing the sintering furnace door, turn on the vacuum pump to draw vacuum for 90 minutes to ensure that the vacuum degree of the sintering furnace is 10 -2 After that, argon gas is introduced into the vacuum sintering furnace. When the vacuum degree is reduced to 0, the exhaust switch is turned on. When Ar gas is detected at the exhaust port, heating is started; the temperature is raised to 360°C at a rate of 1.5°C / min and kept for 30 minutes, at which time the binder is gasified and volatilized; the temperature is then raised to 1400°C at a rate of 15°C / min and kept for 120 minutes, at which time the NiO spherical powder is metallurgically combined with the 316L stainless steel forming; then the exhaust valve is closed, the Ar gas is turned off and the furnace is cooled to room temperature to obtain multi-layer thin-walled NiO / 316L hollow spheres. After testing, the outer diameter of the multi-layer thin-walled NiO / 316L hollow spheres is 6.2-6.6 mm, of which the wall thickness of the NiO layer is 200-600 μm.
[0034] Comparative Example 1
[0035] Comparative Example 1 is a multilayer thin-walled NiO hollow sphere made by using polystyrene spheres as a template agent, and the preparation method includes the following steps:
[0036] S1, putting polystyrene balls with an average diameter of 3 mm into the rolling device of the automatic coating machine, adding NiO spherical powder with a particle size of 40-65 μm thereto; turning on the rolling device; adjusting the rotation speed of the rolling device to 200 r / min; using a polyvinyl alcohol aqueous solution with a concentration of 4.5% as a binder, and the amount of the binder is 1 / 10 of the mass of the NiO spherical powder; at the same time, spraying the atomized binder solution into the rolling device through a nozzle device, and the coating time is 15 minutes; after the coating is completed, taking out the blank, and naturally drying it at a room temperature of 30-35° C., and the drying time is 90 minutes, to obtain a multi-layer hollow spherical blank;
[0037] S2, put the multilayer hollow spherical embryo into a white alumina crucible, and then put it into a vacuum sintering furnace at room temperature; after closing the sintering furnace door, turn on the vacuum pump to draw vacuum for 90 minutes to ensure that the vacuum degree of the sintering furnace is 10 -2 Then, argon gas is introduced into the vacuum sintering furnace. When the vacuum degree is reduced to 0, the exhaust switch is turned on. When Ar gas is detected at the exhaust port, heating is started; the temperature is raised to 350°C at a rate of 2°C / min and kept for 30 minutes. At this time, the binder is gasified and volatilized; the temperature is then raised to 1350°C at a rate of 10°C / min and kept for 120 minutes. At this time, the polystyrene balls are burned off, leaving only NiO spherical powder through metallurgical forming; then the exhaust valve is closed, the Ar gas is turned off and the furnace is cooled to room temperature to obtain multi-layer thin-walled NiO hollow balls. After testing, the outer diameter of the multi-layer thin-walled NiO hollow balls is 3.5-4 mm, and the wall thickness of the NiO layer is 500-1000 μm.
[0038] Test experiment example
[0039] Multilayer thin-walled NiO / 316L hollow spheres were added to the self-developed decarbonization absorbent with ethanolamine (MDEA) as the main component, and a CO2 adsorption and desorption cycle test was carried out. After the desorption was completed, the mass reduction per unit time was calculated as the desorption rate. The test results are listed in Table 1.
[0040] Table 1CO 2 Desorption rate table
[0041]
[0042] As can be seen from Table 1, compared with no catalyst and NiO powder as a catalyst, the CO2 desorption rate of Example 1-2 is greatly increased. Although Comparative Example 1 also has good catalytic activity, it was found during the experiment that these NiO hollow balls will break and collapse after one use, resulting in a sharp decrease in catalytic activity compared with Comparative Example 1. The stainless steel shell of Example 1-2 can effectively improve the strength of the NiO hollow balls, so that the deformation behavior of the hollow balls under different stress states changes from brittle fracture to plastic fracture; while providing support, stainless steel can also generate Fe-Ni series compounds with NiO, further enhancing the catalytic effect.
Claims
1. A multi-layer thin-walled NiO / stainless steel hollow sphere for catalyzing the decomposition of amine absorbents, characterized in that: The catalyst uses a stainless steel hollow sphere as the inner layer structure and template, and NiO powder is coated on the surface of the stainless steel hollow sphere by a coating method to obtain a multi-layer hollow sphere embryo; the NiO powder is sintered in a vacuum sintering furnace to form a layer of NiO shell on the outer surface of the stainless steel hollow sphere, thereby obtaining a multi-layer porous thin-walled NiO hollow sphere.
2. The multi-layer thin-walled NiO / stainless steel hollow sphere according to claim 1, characterized in that: The stainless steel hollow ball is a 316L stainless steel hollow ball.
3. The multi-layer thin-walled NiO / stainless steel hollow sphere according to claim 1, characterized in that: The diameter of the multi-layer thin-wall NiO / stainless steel hollow sphere is 2-10 mm, wherein the wall thickness of the NiO layer is 10-1000 μm.
4. The multi-layer thin-walled NiO / stainless steel hollow sphere according to claim 1, characterized in that: The NiO spherical powder is prepared by gas atomization, water atomization or mechanical ball milling, has a particle size of no more than 70 μm and is spherical or irregular in shape.
5. The method for preparing multi-layer thin-walled NiO / stainless steel hollow spheres according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: using a stainless steel hollow ball as an inner layer structure and a template, spraying metal oxide powder and a mist binder solution onto the surface of the stainless steel hollow ball, coating the metal oxide powder on the surface of the stainless steel hollow ball, and naturally drying to obtain a multi-layer hollow ball embryo; sintering the multi-layer hollow ball embryo and removing the binder.
6. The method for preparing multi-layer thin-walled NiO / stainless steel hollow spheres according to claim 5, characterized in that: The method comprises the following steps: (1) placing a stainless steel hollow ball in NiO spherical powder and rolling it, and spraying a mist binder solution therein at the same time, so that the NiO spherical powder is bonded and coated on the surface of the stainless steel hollow ball; (2) drying the powder naturally after coating to obtain a multi-layer hollow ball embryo; (3) placing the multi-layer hollow ball embryo in an argon-protected vacuum sintering furnace for sintering to obtain the multi-layer thin-wall NiO / stainless steel hollow ball.
7. The method for preparing multi-layer thin-walled NiO / stainless steel hollow spheres according to claim 6, characterized in that: The step (1) is: placing a stainless steel hollow ball into a rolling device of an automatic coating machine, and adding NiO powder thereto; after starting the rolling, using a nozzle device of the automatic coating machine to spray a mist adhesive solution onto the surface of the stainless steel hollow ball, so that the NiO powder is bonded and coated on the surface of the stainless steel hollow ball.
8. The method for preparing multi-layer thin-walled NiO / stainless steel hollow spheres according to claim 6, characterized in that: The mist binder solution is a polyvinyl alcohol aqueous solution with a mass concentration of 2% to 6%, and the spraying amount thereof is 1 / 10 to 1 / 8 of the mass of the NiO powder.
9. The method for preparing multi-layer thin-walled NiO / stainless steel hollow spheres according to claim 6, characterized in that: The drying temperature in step (2) is 10 to 50° C., and the drying time is 30 to 120 minutes.
10. The method for preparing multi-layer thin-walled NiO / stainless steel hollow spheres according to claim 6, characterized in that: In the step (3), the multilayer hollow spherical embryo is placed in a vacuum sintering furnace at room temperature and the furnace door is closed; the vacuum pump is turned on and when the vacuum degree reaches 10 -2 The vacuum sintering furnace is filled with argon; the argon is continuously passed and the temperature is raised to 330-400°C (preferably 330-360°C, for example 350°C) at a rate of 1.5-2.5°C / min, and the temperature is kept at that rate for 20-50min to remove the binder; the temperature is then raised to 1100-1200°C at a rate of 10-15°C / min and the temperature is kept at that rate for 100-150min; and the multilayer thin-walled NiO / stainless steel hollow spheres are obtained after cooling in the furnace.