Manganese-titanium spherical activated carbon molding catalytic material and application thereof

Abstract

The invention discloses a manganese-titanium spherical activated carbon molding catalytic material and application thereof, and belongs to the technical field of catalytic materials. According to the manganese-titanium spherical activated carbon formed catalyst, manganese and titanium are used as active components, and spherical activated carbon is used as a carrier. Manganese and titanium on the surface of the prepared manganese-titanium spherical activated carbon formed catalyst form Lewis acid sites, the spherical activated carbon provides abundant pore channels, the contact area between the active sites and reactants is increased, and the activity of the catalyst is effectively improved. In addition, manganese, titanium and carbon atoms on the surface of the activated carbon carrier form stable three-coordination and four-coordination structures, so that the stability of metal sites is enhanced, and the high temperature resistance, alkali resistance and stability of the catalyst are improved. The problems of the existing solid acid catalyst are effectively solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalytic materials, and more specifically relates to a manganese-titanium spherical activated carbon formed catalytic material and its application. Background Art

[0002] In the field of carbon capture in the power industry, the post-combustion chemical absorbent technology has the advantages of fast absorption rate and large absorption capacity, and can handle large-flow and low-pressure CO2 tail gas. It is currently the most mature and typical technology. In order to improve the desorption rate of CO2 in the regeneration tower in the post-combustion chemical absorbent technology and reduce the desorption energy consumption, researchers have proposed a solid acid catalytic desorption technology, which uses the protonic acid ( acid) and electronic acid (Lewis acid) on the surface of the solid acid catalyst to increase the proton transfer rate of the desorption system, lower the energy barrier of the CO2 desorption reaction, and achieve low-temperature desorption (100 - 110 °C) of the saturated alkanolamine solution. Reducing the desorption energy consumption through the catalytic action of the solid acid is not only beneficial to improving the energy utilization rate of the capture process, but also can slow down the thermal degradation of the amine solution and reduce the corrosion of the regeneration equipment, thereby significantly reducing the operating cost of the capture system.

[0003] At present, there are mainly three types of solid acids applied to catalyze CO2 desorption: metal oxides, molecular sieves, and composite materials of metal oxides and molecular sieves. Metal oxide-based solid acids are prone to leaching of metal ions at high temperatures and in alkaline environments, resulting in serious deactivation of the catalyst, and the leached ions will also accelerate the oxidative degradation of the alkanolamine solution, seriously affecting the stability of the capture system. The pores of molecular sieve and composite solid acid catalysts are easily blocked, and the catalytic performance deteriorates severely after long-term operation. Replacing or regenerating them greatly increases the desorption cost. Therefore, developing a highly efficient solid acid catalyst with stable performance is the key to promoting the catalytic desorption technology. However, the solid acid catalytic desorption materials are still in the initial stage of research and development, and the reported materials are still in powder form, which is easy to block equipment during the alkanolamine circulation process and also increases the filling difficulty, unable to meet the actual carbon capture operation requirements.

[0004] How to solve the above problems existing in the existing solid acid catalysts and realize the popularization and application of the catalytic desorption technology has become the research focus in this field. Summary of the Invention

[0005] The purpose of the present invention is to provide a manganese-titanium spherical activated carbon formed catalytic material and its application to solve the problems existing in the above-mentioned prior art, and to prepare a solid acid catalyst with high catalytic activity, more stable performance, not blocking equipment, and easier to fill.

[0006] To achieve the above purpose, the present invention provides the following solutions:

[0007] One of the technical solutions of the present invention: Provide a manganese-titanium spherical activated carbon formed catalyst, wherein the manganese-titanium spherical activated carbon formed catalyst uses manganese and titanium as active components and spherical activated carbon as a carrier.

[0008] Preferably, the particle size of the spherical activated carbon is 3-6 mm; the manganese-titanium spherical activated carbon formed catalyst is a spherical solid with a particle size of 3-6 mm.

[0009] In the present invention, using manganese and titanium as active components, compared with other metals (such as iron, nickel, cobalt, etc.), manganese and titanium are more stable and not easily cause the degradation of the absorbent at the absorption end. Using spherical activated carbon as a carrier, compared with other carriers (such as molecular sieves, porous ceramics, etc.), the activated carbon has a larger specific surface area and a wide pore size distribution, has good thermal stability and chemical stability, and the cost raw material source is wide, the production cost is relatively low, and the economy is good. The present invention uses spherical activated carbon to solve the problem that traditional powder catalysts are easy to block equipment, and at the same time can avoid the catalyst entering the absorption end and causing the oxidation degradation problem of the absorbent.

[0010] Another technical solution of the present invention: Provide a preparation method of the manganese-titanium spherical activated carbon formed catalyst, comprising the following steps:

[0011] Immerse the spherical activated carbon in a mixed solution composed of a manganese source, a titanium source and water, then perform solid-liquid separation and calcine the obtained solid to obtain the manganese-titanium spherical activated carbon formed catalyst.

[0012] Preferably, the manganese source includes one or more of manganese acetate, manganese nitrate and manganese sulfate.

[0013] Preferably, the titanium source includes titanium tetrachloride and / or titanium sulfate.

[0014] Preferably, the dosage ratio of the manganese source, the titanium source and water is 0-1 g: 0-1 g: 15-25 mL, wherein the dosages of the manganese source and the titanium source are not 0.

[0015] Further, the dosage ratio of the manganese source, the titanium source and water is more preferably 0.5 g: 0.5 g: 20 mL.

[0016] Further, the mixed solution is obtained by ultrasonic mixing of the manganese source, the titanium source and water; the ultrasonic mixing time is 20 min. The present invention does not specifically limit the ultrasonic power of the ultrasonic mixing as long as the mixing is uniform. The present invention also does not specifically limit the dosage ratio of the mixed solution and the spherical activated carbon as long as the mixed solution can submerge the spherical activated carbon.

[0017] Preferably, the mass ratio of the manganese source, the titanium source and the spherical activated carbon is 0-1: 0-1: 5-10, wherein the dosages of the manganese source and the titanium source are not 0.

[0018] Furthermore, the mass ratio of the manganese source, titanium source and spherical activated carbon is more preferably 0.5:0.5:7.

[0019] Preferably, the impregnation time is 24 - 25 h.

[0020] Furthermore, the solid-liquid separation method includes but is not limited to suction filtration.

[0021] Preferably, the calcination is carried out in a protective atmosphere; the calcination temperature is 500 - 800 °C, the heating rate is 5 °C / min, and the holding time is 1 - 4 h.

[0022] Furthermore, the protective atmosphere includes a nitrogen atmosphere.

[0023] Furthermore, the calcination temperature is more preferably 600 - 700 °C, and the holding time is more preferably 2 - 3 h.

[0024] Furthermore, before the calcination, there is also a step of drying the taken solid; the drying method includes vacuum drying; the drying temperature is 70 °C and the time is 2 h.

[0025] The third technical solution of the present invention: Provide the application of the manganese-titanium spherical activated carbon formed catalyst in the catalytic field.

[0026] Preferably, the catalytic field includes the catalytic CO2 desorption field, and the desorption temperature is 90 - 95 °C.

[0027] On the surface of the manganese-titanium spherical activated carbon formed catalyst prepared by the present invention, manganese and titanium metals form Lewis acid sites, and the spherical activated carbon provides rich pores, enhancing the contact area between the active sites and the reactants, and effectively improving the activity of the catalyst. In addition, manganese and titanium metals form stable three-coordination and four-coordination structures with carbon atoms on the surface of the activated carbon carrier, enhancing the stability of the metal sites, and improving the high-temperature resistance, alkali resistance and stability of the catalyst. After 700 min of desorption testing, the performance of the catalyst remains stable, and the desorption amount of CO2 can still remain at a high level.

[0028] Through the synergistic effect of manganese and titanium bimetals and the high specific surface area and porous structure provided by spherical activated carbon, the present invention significantly improves the catalytic efficiency. When applied in low-temperature catalytic CO2 desorption, it can significantly improve the desorption rate and cycling ability.

[0029] In addition, in the present invention, the electronegativities of manganese and titanium ions are different. During the calcination process, manganese is more likely to form a high-valent oxidation state, improving the activity of the catalyst, while titanium is more likely to form a stable tetravalent compound, enhancing the corrosion resistance of the catalyst. Through the synergistic effect of manganese and titanium, as well as the coordination structure formed by the metal and carbon atoms in the activated carbon molding material, the stability and catalytic activity of the catalyst are significantly enhanced, effectively improving the desorption rate and desorption amount of CO2.

[0030] The present invention discloses the following technical effects:

[0031] 1. The manganese-titanium spherical activated carbon molding catalyst obtained in the present invention has excellent high-temperature resistance, alkali resistance and stability. After 700 min of desorption testing, the performance of the catalyst remains stable, and the desorption amount of CO2 can still remain at a high level.

[0032] 2. The manganese-titanium spherical activated carbon molding catalyst obtained in the present invention can effectively improve the desorption rate and desorption amount of CO2. Under the condition that the desorption temperature is 95 °C, the highest desorption rate of CO2 is increased to 2.97 mmol / min. The non-catalytic desorption rate under the same conditions is only 1.39 mmol / min. The manganese-titanium spherical activated carbon molding catalyst increases the desorption rate by 213%. When the desorption reaction proceeds for 60 min, the cumulative amount of CO2 desorbed non-catalytically is 13.48 mmol, and the cumulative amount of CO2 desorbed catalytically is 58.57 mmol. The manganese-titanium spherical activated carbon molding catalyst increases the desorption amount by 4.34 times.

[0033] 3. The manganese-titanium spherical activated carbon molding catalyst obtained in the present invention is a black small ball, which will not block the equipment during use and is easier to load, fully meeting the actual carbon capture operation requirements.

[0034] 4. When the manganese-titanium spherical activated carbon molding catalyst obtained in the present invention is used for catalyzing the desorption of CO2, the desorption temperature only needs to be 90-95 °C, greatly reducing the energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a physical picture of the Mn-Ti@C catalyst prepared in Example 1;

[0036] Figure 2 It is a schematic diagram of the device for desorption performance testing;

[0037] Figure 3 It is the highest desorption rate under non-catalytic conditions (blank) and Ti@C catalyst, Mn@C catalyst and Mn-Ti@C catalyst;

[0038] Figure 4 It is the desorption amount under non-catalytic conditions (blank) and Mn-Ti@C catalyst;

[0039] Figure 5 The desorption amounts of the Mn-Ti@C catalysts with dosages of 0.5 g, 1 g, 1.5 g, and 2 g;

[0040] Figure 6 The desorption amounts of the Mn-Ti@C catalysts at desorption temperatures of 85 °C, 90 °C, and 95 °C;

[0041] Figure 7 The change in the desorption amount of the Mn-Ti@C catalyst after 10 cycles;

[0042] Figure 8 The XRD diffraction results of the Mn-Ti@C catalyst before and after desorption;

[0043] Figure 9 The Raman spectra of MEA under non-catalytic conditions and Mn-Ti@C catalytic conditions;

[0044] Figure 10 The maximum desorption rate and desorption amount of the catalysts obtained in Example 1 and Comparative Example 3 under non-catalytic conditions (blank); Detailed Embodiments

[0045] Now, various exemplary embodiments of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0046] It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0047] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0048] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0049] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0050] The post-combustion chemical absorbent technology mainly uses alcohol amine solution as the absorbent. During the capture process, the low-load alcohol amine reacts with CO2 at a low temperature in the absorber tower and is discharged after the decarbonized flue gas is treated. At the same time, the high-load absorbent passes through the heat exchanger and enters the desorption tower for high-temperature regeneration, releasing pure CO2 gas for further compression, storage, conversion and utilization, and the absorbent is pumped into the absorption tower again to complete the cycle. However, the alcohol amine absorption products, carbamate and protonated amine, are very stable, and a large amount of high-grade heat source needs to be invested in the regeneration tower for the desorption reaction to occur. High temperature also causes the gasification of water, taking away a large amount of latent heat of evaporation. Therefore, in the process of alcohol amine absorption carbon capture, the desorption temperature is as high as 120-130°C, and the desorption energy consumption is about 3.6GJ / tCO2, accounting for more than 70% of the overall process operation energy consumption. In order to increase the desorption rate of CO2 in the regeneration tower in the post-combustion chemical absorbent technology and reduce the desorption energy consumption, the researchers proposed a solid acid catalytic desorption technology. However, the solid acid catalysts commonly used in the existing solid acid catalytic desorption technology have problems such as poor stability, difficulty in loading, and easy clogging of equipment, which greatly affects the desorption efficiency.

[0051] The manganese-titanium spherical activated carbon shaped catalyst of the present invention has high catalytic activity, more stable performance, will not clog equipment, and is easier to load, effectively solving the problems existing in existing solid acid catalysts.

[0052] The manganese-titanium spherical activated carbon shaped catalyst of the present invention is described in detail below.

[0053] The spherical activated carbon and columnar activated carbon used in the following examples and comparative examples were purchased from Pingdingshan Green Source Activated Carbon Co., Ltd. The particle size of the spherical activated carbon was 3 to 6 mm.

[0054] Unless otherwise specified, other raw materials used in the following examples, comparative examples and performance tests are commercially available products, and the sources of the commercially available products have no effect on the effects achieved.

[0055] The room temperature involved in the present invention is 25±5°C unless otherwise specified.

[0056] Example 1

[0057] This embodiment provides a manganese-titanium spherical activated carbon formed catalyst, and the specific preparation steps are as follows:

[0058] Dissolve 0.5 g of manganese acetate and 0.5 g of titanium tetrachloride in 20 mL of deionized water at room temperature, ultrasonically mix for 20 min to obtain a mixed solution; immerse 7 g of spherical activated carbon into the above mixed solution, continue to ultrasonically mix for 20 min, and then let it stand for 24 h. After solid-liquid separation, take the solid and vacuum dry it at 70 °C for 2 h, then place it in a tubular furnace, and heat it to 700 °C at a heating rate of 5 °C / min under a nitrogen atmosphere, keep it warm for 2 h, and after natural cooling, obtain black spheres with a particle size of 3-6 mm, which is the manganese-titanium spherical activated carbon formed catalyst, denoted as Mn-Ti@C.

[0059] The physical picture of the manganese-titanium spherical activated carbon formed catalyst prepared in this embodiment is as Figure 1 shown. As Figure 1 can be seen, the catalyst prepared in this embodiment is spherical, which can effectively solve the problem that traditional powder catalysts are easy to block equipment, and at the same time can avoid the catalyst from entering the absorption end and causing the oxidation and degradation problem of the absorbent.

[0060] Example 2

[0061] This embodiment provides a manganese-titanium spherical activated carbon formed catalyst, and the specific preparation steps are as follows:

[0062] Dissolve 0.8 g of manganese acetate and 0.1 g of titanium tetrachloride in 20 mL of deionized water at room temperature, ultrasonically mix for 20 min to obtain a mixed solution; immerse 6 g of spherical activated carbon into the above mixed solution, continue to ultrasonically mix for 20 min, and then let it stand for 24 h. After solid-liquid separation, take the solid and vacuum dry it at 70 °C for 2 h, then place it in a tubular furnace, and heat it to 800 °C at a heating rate of 5 °C / min under a nitrogen atmosphere, keep it warm for 2 h, and after natural cooling, obtain black spheres with a particle size of 3-6 mm, which is the manganese-titanium spherical activated carbon formed catalyst.

[0063] Example 3

[0064] This embodiment provides a manganese-titanium spherical activated carbon formed catalyst, and the specific preparation steps are as follows:

[0065] Dissolve 0.2 g of manganese acetate and 0.7 g of titanium tetrachloride in 25 mL of deionized water at room temperature, and ultrasonically mix for 20 min to obtain a mixed solution; Immerse 10 g of spherical activated carbon into the above mixed solution, continue to ultrasonically mix for 20 min, and then let it stand for 24 h. After solid-liquid separation, take the solid and vacuum dry it at 70 °C for 2 h, then place it in a tube furnace, heat it to 600 °C at a heating rate of 5 °C / min under a nitrogen atmosphere, keep it at this temperature for 3 h, and naturally cool it to obtain black spheres with a particle size of 3 - 6 mm, which is the manganese-titanium spherical activated carbon formed catalyst.

[0066] Comparative Example 1

[0067] This comparative example provides a manganese spherical activated carbon formed catalyst, and the specific preparation steps are as follows:

[0068] The difference from Example 1 is that the addition of titanium tetrachloride is omitted, and the others are the same as in Example 1. Finally, black spheres with a particle size of 3 - 6 mm are obtained, which is the manganese spherical activated carbon formed catalyst, denoted as Mn@C.

[0069] Comparative Example 2

[0070] This comparative example provides a titanium spherical activated carbon formed catalyst, and the specific preparation steps are as follows:

[0071] The difference from Example 1 is that the addition of manganese acetate is omitted, and the others are the same as in Example 1. Finally, black spheres with a particle size of 3 - 6 mm are obtained, which is the titanium spherical activated carbon formed catalyst, denoted as Ti@C.

[0072] Comparative Example 3

[0073] This comparative example provides a manganese-titanium columnar activated carbon formed catalyst, and the specific preparation steps are as follows:

[0074] The difference from Example 1 is that the spherical activated carbon is replaced with columnar activated carbon with a size of 4 mm (diameter) × 10 mm (height), and the others are the same as in Example 1. Finally, a black column with a size of 4 mm (diameter) × 10 mm (height) is obtained, which is the manganese-titanium columnar activated carbon formed catalyst.

[0075] Desorption performance test:

[0076] The desorption performance test device is as Figure 2As shown, it consists of a magnetic stirring constant temperature oil bath, an online gas flowmeter, a silica gel drying tube, a condenser and a desktop computer, which monitors the flow rate and cumulative amount of CO2 released from the alkanolamine solution at a certain heating temperature, so as to evaluate the activity of the catalyst. The specific steps are as follows: Heat the oil bath and set the magnetic stirring rate to 200 r / min; Measure 300 mL of ethanolamine (MEA) solution saturated with absorption and place it in a 500 mL round-bottom flask, and add the catalyst; Turn on the condensed water, and the desorbed CO2 gas enters the silica gel drying tube through the condenser to fully remove water vapor; After drying, the gas flows into the gas flowmeter, and the instantaneous flow rate of CO2 is recorded through the connected computer.

[0077] The desorption amount and desorption rate of CO2 are calculated by the following formula:

[0078]

[0079] In the formula: n CO2 (t) — The content of CO2 at the outlet of the experimental device at time t, mmol;

[0080] V M — The molar volume of the gas at room temperature, mL / mmol;

[0081] V CO2 (t) — The instantaneous flow rate of CO2 at the outlet of the experimental device, mmol / min;

[0082] R — The desorption rate of CO2 at the outlet of the experimental device, mmol / min;

[0083] n CO2 — The content of CO2 at the outlet of the experimental device, mmol;

[0084] t — The reaction time, min.

[0085] 1. Test the desorption performance of non-catalytic conditions (blank) and Ti@C catalyst, Mn@C catalyst and Mn-Ti@C catalyst according to the above method. The dosage of each catalyst is 1 g and the desorption temperature is 95 °C. The highest desorption rate obtained is as Figure 3 shown.

[0086] Figure 3 is the highest desorption rate of non-catalytic conditions (blank) and Ti@C catalyst, Mn@C catalyst and Mn-Ti@C catalyst. From Figure 3It can be seen that under non-catalytic conditions, the highest desorption rate of CO2 is 1.39 mmol / min; under catalytic conditions, the highest desorption rates corresponding to the Ti@C catalyst, Mn@C catalyst, and Mn-Ti@C catalyst are 2.42 mmol / min, 2.59 mmol / min, and 2.97 mmol / min, respectively. Among them, Mn-Ti@C has the best desorption performance, which is 213% of that under non-catalytic conditions, indicating that the catalyst described in the present invention increases the desorption rate by 213%. Therefore, Mn-Ti@C exhibits better performance than single-metal catalysts, which is due to the synergistic effect of the bimetals, significantly improving the activity of the catalyst by accelerating the proton cycle.

[0087] 2. Test the change of the desorption amount of CO2 with time under non-catalytic conditions (blank) and the Mn-Ti@C catalyst according to the above method. The dosage of the Mn-Ti@C catalyst is 1 g, and the desorption temperature is 95 °C. The results are as Figure 4 shown.

[0088] Figure 4 are the desorption amounts under non-catalytic conditions (blank) and the Mn-Ti@C catalyst. It can be Figure 4 seen that under non-catalytic conditions, the cumulative desorption amount of CO2 at 60 min of the desorption reaction is 13.48 mmol. Under the catalytic conditions of the Mn-Ti@C catalyst, the desorption amounts of CO2 corresponding to 30 min, 45 min, and 60 min of the desorption reaction are 25.57 mmol, 48.18 mmol, and 58.57 mmol, respectively. When the desorption reaction proceeds for 60 min, the cumulative desorption amount of CO2 under non-catalytic conditions is 13.48 mmol, and the cumulative desorption amount of CO2 catalyzed by the Mn-Ti@C catalyst is 58.57 mmol. The Mn-Ti@C catalyst increases the desorption amount by 4.34 times. Thus, compared with non-catalytic conditions, the Mn-Ti@C catalyst can release more CO2 within the same reaction time. In the actual regeneration process, the residence time is limited. Therefore, the use of the Mn-Ti@C catalyst will have a significant effect on improving the desorption efficiency in the regeneration tower and increasing the amine circulation capacity.

[0089] 3. Test the effect of the dosage of the Mn-Ti@C catalyst on the desorption rate according to the above method. The dosages of the Mn-Ti@C catalyst are 0.5 g, 1 g, 1.5 g, and 2 g, respectively, and the desorption temperature is 95 °C. The obtained results are as Figure 5 shown.

[0090] Figure 5 are the desorption amounts of the Mn-Ti@C catalyst with dosages of 0.5 g, 1 g, 1.5 g, and 2 g. It can be Figure 5It can be seen that when the dosage increases from 0.5 g to 1 g, the maximum desorption rate of CO2 catalyzed by the Mn-Ti@C catalyst increases significantly; when the dosage increases from 1.5 g to 2 g, the change in the maximum desorption rate of CO2 catalyzed by the Mn-Ti@C catalyst is not significant. The above test results indicate that the catalyst has a significant effect on the desorption rate within the appropriate dosage range, and exceeding this range will lead to waste of the catalyst.

[0091] When the dosage of the Mn-Ti@C catalyst is only 0.5 g, the maximum desorption rate of CO2 is 2.1 mmol / min, which is higher than the maximum desorption rate of CO2 under non-catalytic conditions, fully indicating that the Mn-Ti@C catalyst has excellent catalytic activity.

[0092] When the dosages of the Mn-Ti@C catalyst are 0.5 g, 1 g, 1.5 g, and 2 g respectively, the desorption amounts of CO2 after 60 min of desorption are 46.16 mmol, 58.57 mmol, 58.56 mmol, and more than 59.12 mmol respectively. The catalytic desorption amount with a Mn-Ti@C catalyst dosage of 0.5 g is 3.4 times that under non-catalytic conditions, and the catalytic desorption amount with a dosage of 2 g is 4.38 times that under non-catalytic conditions. After 60 min of desorption, the desorption amounts corresponding to different dosages of the Mn-Ti@C catalyst gradually tend to be the same. This is because the absorption product carbamate in the desorption liquid decreases significantly, resulting in a rapid decrease in the concentration of the reactants in the desorption system, and the desorption reaction reaches equilibrium. According to the incremental analysis of the dosage and desorption amount, a dosage of 1 g of the Mn-Ti@C catalyst is more appropriate, otherwise it will cause waste of the catalyst.

[0093] 4. According to the above method, the effect of the desorption temperature on the desorption rate of the Mn-Ti@C catalyst was tested. The dosage of the Mn-Ti@C catalyst was 1 g, and the desorption temperatures were 85 °C, 90 °C, and 95 °C respectively. The results obtained are as Figure 6 shown.

[0094] Figure 6 The desorption amounts of the Mn-Ti@C catalyst at desorption temperatures of 85 °C, 90 °C, and 95 °C. From Figure 6It can be seen that when the desorption temperature is increased from 85 °C to 95 °C, the maximum desorption rate of CO2 changes significantly: when the desorption temperature is 85 °C, the maximum catalytic desorption rate is only 0.98 mmol / min, which is lower than the desorption rate at 95 °C under non-catalytic conditions; when the desorption temperature is 90 °C, the maximum desorption rate under catalytic conditions is 2.56 mmol / min, which is significantly higher than the desorption rate at 95 °C under non-catalytic conditions; when the desorption temperature is 95 °C, the maximum desorption rate under catalytic conditions is 2.97 mmol / min, and the increase in the desorption rate is limited, but it is still significantly higher than the maximum desorption rate under non-catalytic conditions. Thus, it can be seen that within a certain temperature range, the CO2 desorption rate will increase with the increase of the desorption temperature. The Mn-Ti@C catalyst effectively improves the desorption rate of CO2 at relatively low temperatures, which is of great significance for adjusting the desorption temperature and reducing the desorption energy consumption.

[0095] 5. Test the stability of the Mn-Ti@C catalyst according to the above method:

[0096] Under the conditions of a Mn-Ti@C catalyst dosage of 1 g and a desorption temperature of 95 °C, continuous desorption is carried out for 700 min, with each 70 min as a cycle, and a total of 10 cycles are carried out. The results are as Figure 7 shown.

[0097] Figure 7 is the change in the desorption amount of the Mn-Ti@C catalyst after 10 cycles. From Figure 7 it can be seen that the desorption performance of the Mn-Ti@C catalyst remains stable in the first 4 cycles, and the average maximum desorption rate is about 3 mmol / min; after 10 cycles, the desorption rate of the Mn-Ti@C catalyst is basically stable at 2.1 mmol / min, still higher than that under non-catalytic conditions. This indicates that the catalyst has excellent stability, and its desorption performance is still better than that under non-catalytic conditions after 700 min.

[0098] 6. Characterize the crystal phase structure of the Mn-Ti@C catalyst before desorption and the Mn-Ti@C catalyst after 700 min of desorption. The results are as Figure 8 shown.

[0099] Figure 8 are the XRD diffraction results of the Mn-Ti@C catalyst before and after desorption. Among them, Mn-Ti@C represents the Mn-Ti@C catalyst before desorption, and Mn-Ti@C-MEA represents the Mn-Ti@C catalyst after 700 min of desorption. From Figure 8It can be seen that in the XRD pattern of the Mn-Ti@C catalyst before desorption, typical broad and weak diffraction peaks of activated carbon appeared, mainly in the range of 2θ = 20° - 25°, indicating its amorphous carbon structure. For the Mn-Ti@C catalyst before desorption, in addition to the amorphous characteristics of activated carbon, characteristic diffraction peaks corresponding to the crystal phases of MnO2 and TiO2 were also observed. Among them, the diffraction peaks of MnO2 mainly appeared at 2θ = 35.3° and 43.5°, corresponding to its (110) and (200) crystal planes; the characteristic peak of the anatase phase of TiO2 was located at 2θ = 49.4°, attributed to the (200) crystal plane. The presence of these characteristic diffraction peaks indicates that manganese and titanium were successfully loaded and formed the corresponding oxide crystal phases. At the same time, the intensity of the diffraction peaks was relatively low, which was related to the high surface area of the activated carbon matrix and the high dispersion of metal oxides. The results of the crystal phase structure characterization of the Mn-Ti@C catalyst after 700 min of desorption showed that the XRD patterns of the Mn-Ti@C catalyst before and after desorption were consistent, proving the high stability of the Mn-Ti@C catalyst in an alkaline and high-temperature environment, indicating that the catalyst could maintain excellent catalytic activity during long-term operation.

[0100] 7. The decomposition mechanisms of the absorption products bicarbonate (HCO3 - ), carbonate (CO3 2- ), and carbamate (RNHCOO - ) under non-catalytic conditions and Mn-Ti@C catalytic conditions were studied. The dosage of the Mn-Ti@C catalyst was 1 g, the desorption temperature was 95 °C, and the desorption time was 30 min. The obtained results are as Figure 9 shown.

[0101] Figure 9 are the Raman spectra of MEA under non-catalytic conditions and Mn-Ti@C catalytic conditions. Among them, Mn-Ti@C-30min represents the Mn-Ti@C catalytic condition, and Un-catalytic-30min represents the non-catalytic condition. The results show that the characteristic peaks at 1018, 1066, and 1159 cm -1 correspond to the C-OH stretching vibration in the HCO3 - structure, the symmetric C-O stretching vibration of CO3 2- , and the C-N stretching vibration of RNHCOO - , respectively. The results show that under non-catalytic conditions, the intensities of the three characteristic peaks of CO3 2- , HCO3 - , and RNHCOO - were significantly different. Compared with the non-desorbed MEA under non-catalytic conditions, the peak intensity of MEA under catalytic conditions was significantly reduced, indicating that more absorption products decomposed into CO2.

[0102] 8. Test the desorption performance of the catalysts obtained under non-catalytic conditions (blank), Example 1 and Comparative Example 3 according to the above method. The dosage of each catalyst is 1 g, and the desorption temperature is 95 °C. The highest desorption rate and the change of desorption amount with time are as Figure 10 shown.

[0103] Figure 10 The highest desorption rate and desorption amount of the catalysts obtained under non-catalytic conditions (blank), Example 1 and Comparative Example 3. As Figure 10 can be seen, at the same catalyst dosage, the highest desorption rate and desorption amount of the spherical catalyst are better than those of the columnar catalyst. This is because the specific surface area of the spherical catalyst is larger, and the resistance of the spherical formed catalyst to the liquid is smaller, which helps the uniform distribution of reactants and products. In addition, from the perspective of processing, the spherical catalyst is easier to prepare. The distribution of mechanical stress and thermal stress of the spherical catalyst in the reactor is more uniform, reducing the risk of breakage and wear. Compared with the columnar catalyst, the spherical catalyst is also easier to fill and unload, greatly simplifying the loading and recovery processes and reducing the operation cost. Therefore, the spherical catalyst has more advantages.

[0104] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other.

[0105] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A manganese-titanium spherical activated carbon catalyst, characterized in that: The manganese-titanium spherical activated carbon shaped catalyst uses manganese and titanium as active components and spherical activated carbon as a carrier.

2. The manganese-titanium spherical activated carbon shaped catalyst according to claim 1, characterized in that: The particle size of the spherical activated carbon is 3 to 6 mm; the manganese-titanium spherical activated carbon shaped catalyst is a spherical solid with a particle size of 3 to 6 mm.

3. The method for preparing the manganese-titanium spherical activated carbon shaped catalyst according to claim 1 or 2, characterized in that: The steps include: The spherical activated carbon is placed in a mixed solution consisting of a manganese source, a titanium source and water for immersion, and then the solid-liquid separation is performed to obtain the solid for calcination to obtain the manganese-titanium spherical activated carbon formed catalyst.

4. The preparation method according to claim 3, characterized in that: The manganese source includes one or more of manganese acetate, manganese nitrate and manganese sulfate; the titanium source includes titanium tetrachloride and / or titanium sulfate.

5. The preparation method according to claim 3, characterized in that: The dosage ratio of the manganese source, the titanium source and water is 0-1g:0-1g:15-25mL, wherein the dosage of the manganese source and the titanium source is not 0.

6. The preparation method according to claim 3, characterized in that: The mass ratio of the manganese source, the titanium source and the spherical activated carbon is 0-1:0-1:5-10, wherein the dosage of the manganese source and the titanium source is not zero.

7. The preparation method according to claim 3, characterized in that: The immersion time is 24 to 25 hours.

8. The preparation method according to claim 3, characterized in that: The calcination is carried out under a protective atmosphere; the calcination temperature is 500-800° C., the heating rate is 5° C. / min, and the heat preservation time is 1-4 hours.

9. Use of the manganese-titanium spherical activated carbon shaped catalyst according to claim 1 or 2 in the field of catalysis.

10. The use according to claim 9, characterized in that: The catalytic field includes the field of catalytic CO2 desorption, and the desorption temperature is 90-95°C.

Images