Methods for capturing and recovering carbon dioxide from FCC flue gas
By combining composite amine liquid with zirconium-based catalysts and nickel salts, and optimizing the component ratio and equipment selection, the problems of high energy consumption and corrosion in carbon dioxide capture of FCC flue gas were solved, achieving efficient and low-energy carbon dioxide recovery.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2024-12-27
- Publication Date
- 2026-06-30
AI Technical Summary
In existing technologies, carbon dioxide capture methods in FCC flue gas suffer from high energy consumption, amine degradation, and equipment corrosion, making it difficult to achieve efficient and low-energy carbon dioxide recovery.
A composite amine liquid (polyene amine and alkanolamine) was combined with zirconium-based catalyst and nickel salt. The component ratio was optimized, and the particle size of the zirconium-based catalyst and the gas-liquid flow rate were combined to use a bubble column and a sieve plate column for carbon dioxide capture and regeneration.
It improves carbon dioxide capture efficiency, reduces energy consumption, and significantly improves amine degradation and equipment corrosion, achieving efficient and low-energy carbon dioxide recovery.
Smart Images
Figure BDA0005214989060000121
Abstract
Description
Technical Field
[0001] This invention relates to the field of industrial gas treatment, and specifically to a method for capturing and recovering carbon dioxide from FCC flue gas. Background Technology
[0002] Fluid catalytic cracking (FCC) is one of the most important conversion processes in oil refineries. The flue gas emitted during this process contains large amounts of sulfur oxides, nitrogen oxides, carbon dioxide, and catalyst dust, causing serious environmental pollution. After treating the sulfur oxides and nitrogen oxides in the FCC flue gas, the carbon dioxide it contains can be recovered, thereby reducing carbon emissions.
[0003] Currently, the most researched and technologically mature carbon dioxide capture technology is post-combustion capture, including chemical absorption, physical absorption, and membrane separation. Among these, chemical absorption utilizes alkaline liquids as absorbents to directly separate carbon dioxide from flue gas. It boasts high separation efficiency and low cost, making it the most mature and widely used carbon dioxide capture process. The absorbent is crucial for chemical absorption, determining the carbon dioxide absorption efficiency and the energy consumption of the entire carbon capture system. Furthermore, mitigating the amine degradation and equipment corrosion problems caused by alkaline absorbents is a key research focus. Therefore, providing a high-performance absorbent with low energy consumption and low degradation / corrosion rates, and further optimizing processes, equipment, and conditions to achieve a more effective overall carbon dioxide capture and recovery system for better recovery of carbon dioxide from FCC flue gas, is a pressing issue that needs to be addressed. Summary of the Invention
[0004] The purpose of this invention is to overcome the problems existing in the prior art and provide a method for capturing and recovering carbon dioxide from FCC flue gas. This method has high carbon dioxide capture efficiency, low energy consumption, and improves the phenomena of amine degradation and equipment corrosion.
[0005] To achieve the above objectives, the present invention provides a method for capturing and recovering carbon dioxide from FCC flue gas, the method comprising:
[0006] FCC flue gas is fed to an absorption tower and reacted with the absorbent to obtain a rich liquid that absorbs carbon dioxide. The rich liquid is then fed to a regeneration tower for thermal regeneration to obtain a lean liquid. The lean liquid is then fed back to the absorption tower for recycling.
[0007] The absorbent comprises 10-40 wt% of a composite amine solution, 0.01-0.5 wt% of a zirconium-based catalyst, 2-6 wt% of a nickel salt and water; the composite amine solution comprises polyene amine and alkanolamine, wherein the volume ratio of the polyene amine to the alkanolamine is 1:0.2-0.5.
[0008] This invention provides a method for capturing and recovering carbon dioxide from FCC flue gas by designing a special absorbent. Through the synergistic effect of its components, the absorbent achieves excellent carbon dioxide absorption efficiency and effectively reduces energy consumption, while also mitigating amine degradation and equipment corrosion during the capture and recovery process. Detailed Implementation
[0009] The endpoints and any values of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.
[0010] This invention provides a method for capturing and recovering carbon dioxide from FCC flue gas, the method comprising:
[0011] FCC flue gas is fed to an absorption tower and reacted with the absorbent to obtain a rich liquid that absorbs carbon dioxide. The rich liquid is then fed to a regeneration tower for thermal regeneration to obtain a lean liquid. The lean liquid is then fed back to the absorption tower for recycling.
[0012] The absorbent comprises 10-40 wt% of a composite amine solution, 0.01-0.5 wt% of a zirconium-based catalyst, 2-6 wt% of a nickel salt and water; the composite amine solution comprises polyene amine and alkanolamine, wherein the volume ratio of the polyene amine to the alkanolamine is 1:0.2-0.5.
[0013] According to the present invention, polyene amines have good carbon dioxide capture effect, but they also have the drawbacks of high energy consumption and corrosion of equipment. By introducing a small amount of alkanolamine to form a composite amine liquid and combining it with zirconium-based catalyst and nickel salt, and by adjusting the content of each component, the performance can be improved by multiple times and the heat transfer process and mass transfer process in the desorption process can be optimized and enhanced. This makes the absorbent liquid have good selectivity for carbon dioxide, strong capture capacity, and reduced energy consumption, while significantly reducing its amine liquid degradation and corrosion rate.
[0014] According to the present invention, the zirconium-based catalyst, using inorganic nanoparticles as a support, has a small particle size and can adhere to the liquid surface, thereby increasing the contact area between the gas and liquid phases. Simultaneously, in the presence of the zirconium-based catalyst, the surface tension of the composite amine solution obtained by combining polyene amines with a small amount of alkanolamines also decreases. While enhancing the performance of the composite amine solution, the zirconium-based catalyst and nickel salt can also inhibit the degradation of the amine solution, promote the desorption reaction, and lower the pH of the absorbent, thus promoting the formation of more bicarbonate ions. Furthermore, it can also act as a thermal buffer, reducing the energy consumption for the thermal desorption and regeneration of the absorbent.
[0015] According to the present invention, the contents of the composite amine solution, zirconium-based catalyst, and nickel salt in the absorbent should be coordinated to achieve the optimal synergistic effect. Adjusting the three to a suitable range can maximize their respective effects and promote each other. The selection and content of each component in the absorbent affect the performance of the final absorbent. To obtain an absorbent with better performance, preferably, the content of the composite amine solution in the absorbent is 20-30 wt%, for example, it can be 20 wt%, 25 wt%, 28 wt%, and 30 wt%, or any value within any range thereof.
[0016] Preferably, the zirconium-based catalyst in the absorbent is present in an amount of 0.05-0.2 wt%, for example, 0.05 wt%, 0.1 wt%, 0.15 wt%, and 0.2 wt%, or any value within these ranges. As the content increases, the effective absorption ratio of carbon dioxide first increases and then decreases; therefore, it needs to be set within a suitable range to achieve the best absorption effect.
[0017] Preferably, the nickel salt content in the absorbent is 3-5 wt%, for example, it can be 3 wt%, 4 wt%, 4.5 wt%, and 5 wt%, or any value between these values. Lower nickel salt content allows for higher carbon dioxide loading when combined with other components, while higher content provides greater thermal compensation to reduce energy consumption. However, as the nickel salt content gradually increases, the improvement in absorbent performance due to nickel salt decreases. Therefore, considering performance, cost, and equipment requirements, the nickel salt content needs to be adjusted within a suitable range.
[0018] Preferably, the volume ratio of the polyene amine to the alkanolamine is 1:0.2-0.3, for example, it can be 1:0.2, 1:0.25 and 1:0.3 and any range between these values.
[0019] Preferably, the polyene amine is selected from one or more of diethylenetriamine, triethylenetetramine, tetraethylenepentamine and pentaethylenehexamine, and is more preferably triethylenetetramine and / or tetraethylenepentamine;
[0020] Preferably, the alkanolamine is selected from ethanolamine, diethanolamine, triethanolamine, diethanolisopropanolamine, and triisopropanolamine, and more preferably one or more of triethanolamine, diethanolisopropanolamine, and triisopropanolamine.
[0021] Preferably, the nickel salt is selected from one or more of nickel chloride, nickel sulfate, nickel nitrate and nickel carbonate, and is more preferably nickel sulfate and / or nickel nitrate.
[0022] According to the present invention, the absorption of carbon dioxide by the composite amine liquid can be enhanced through the synergistic effect of zirconium-based catalyst and nickel salt. The gas-liquid flow rate affects the enhancement effect. The inventors of this invention have discovered that controlling the gas-liquid flow rate within a certain range can reduce mass transfer resistance and is beneficial to the enhancing effect of the catalyst and nickel salt. To ensure more sufficient contact between the FCC flue gas and the absorbent liquid and to enhance the ability of the catalyst and nickel salt to absorb carbon dioxide by the composite amine liquid, thereby improving absorption efficiency and reducing energy consumption, preferably, relative to 1m... 3 The lean liquor has a circulation rate of / h, and the volumetric flow rate of the FCC flue gas is 100-300 Nm³. 3 / h, preferably 150-250Nm 3 / h, for example, can be 150Nm 3 / h, 180Nm 3 / h, 200Nm 3 / h and 250Nm 3 / h and other values and the range between any of these values. The circulation volume of the lean solution is also the amount of absorbent solution used.
[0023] Preferably, the pressure of the FCC flue gas is 0.1-0.5 MPa, more preferably 0.2-0.4 MPa, for example, it can be 0.2 MPa, 0.25 MPa, 0.3 MPa and 0.4 MPa and any range between these values.
[0024] According to the present invention, in order to obtain better carbon dioxide capture and recovery effects and avoid adverse effects, the FCC flue gas preferably undergoes desulfurization, denitrification, and dust removal treatment. The desulfurization, denitrification, and dust removal treatments can employ commonly known methods in the art, as long as the raw gas is purified to contain only carbon dioxide, oxygen, and nitrogen. For example, a Venturi scrubber can be used for dust removal.
[0025] According to the present invention, in order to improve the efficiency of the carbon capture system and increase the carbon dioxide absorption rate, preferably, the volume content of carbon dioxide in the FCC flue gas is 5-30%, more preferably 10-20%, for example, it can be 10%, 12%, 15%, 18% and 20% and any range between these values.
[0026] According to the present invention, the absorbent exhibits excellent surface and volume effects through the synergistic effect of the composite amine solution, zirconium-based catalyst, and nickel salt. This enhances the mass transfer rate between the gas and liquid phases during carbon dioxide absorption and improves the stability of the absorbent. The nickel salt can also undergo hydrolysis, thereby lowering the pH of the absorbent and providing a favorable environment for bicarbonate generation, facilitating desorption and regeneration of the absorbent. Furthermore, in the presence of the zirconium-based catalyst, the nickel salt, with its strong coordination ability, can form a complex with the composite amine solution. The endothermic dissociation reaction of this complex stores the chemical energy released during carbon dioxide absorption by the amine and regenerates and releases heat during carbon dioxide desorption, thus compensating for the energy required for carbon dioxide desorption and reducing energy consumption.
[0027] According to the present invention, in order to obtain a high-performance zirconium-based catalyst and thereby enhance its synergistic effect with the composite amine liquid and nickel salt to improve the various properties of the absorbent, preferably, the preparation method of the zirconium-based catalyst includes: dissolving zirconium salt in a solvent, adding inorganic nanoparticles for high-temperature reaction to obtain a catalyst precursor, drying and calcining the catalyst precursor, and pulverizing it to obtain the zirconium-based catalyst.
[0028] According to the present invention, in order to make the components more uniformly dispersed and to achieve more sufficient contact, the solvent is preferably selected from one or more of water, methanol, diethyl ether, acetone, acetonitrile, tetrahydrofuran, ethyl acetate, 1,4-dioxane, dimethyl sulfoxide and N,N-dimethylformamide, preferably water and / or ethanol.
[0029] According to the present invention, in order to obtain a better zirconium-based catalyst, preferably, the zirconium salt is selected from one or more of zirconium chloride, zirconium sulfate, zirconium nitrate and zirconium carbonate, and more preferably zirconium sulfate and / or zirconium nitrate.
[0030] Preferably, the concentration of the zirconium salt in the solvent is 30-60 g / L, more preferably 40-50 g / L, for example, it can be 40 g / L, 45 g / L, 48 g / L and 50 g / L and any range between these values.
[0031] Preferably, the inorganic nanoparticles are selected from one or more of aluminum oxide nanoparticles, titanium dioxide nanoparticles, silicon dioxide nanoparticles, magnesium oxide nanoparticles, and iron oxide nanoparticles, and are more preferably aluminum oxide nanoparticles and / or titanium dioxide nanoparticles.
[0032] Preferably, the average particle size of the inorganic nanoparticles is 50-300 nm, more preferably 100-200 nm, and can be, for example, 100 nm, 120 nm, 150 nm, and 200 nm, or any value between these values. By adjusting the average particle size of the inorganic nanoparticles, the particles can have stronger surface activity.
[0033] Preferably, the mass ratio of the zirconium salt to the inorganic nanoparticles is 1:4-10, more preferably 1:6-8, for example, it can be 1:6, 1:6.5, 1:7 and 1:8 and any range between these values.
[0034] According to the present invention, in order to obtain a zirconium-based catalyst with better properties, the conditions for the high-temperature reaction preferably include: temperature 70-100°C and time 8-36h; more preferably, temperature 80-90°C (for example, values such as 80°C, 85°C, 88°C, and 90°C, and any range thereof) and time 12-24h (for example, values such as 12h, 16h, 20h, and 24h, and any range thereof).
[0035] Preferably, after the high-temperature reaction is completed, the resulting mixture is filtered, and the resulting filter cake is washed. The washing solvent is selected from one or more of water, methanol, diethyl ether, acetone, acetonitrile, tetrahydrofuran, ethyl acetate, 1,4-dioxane, dimethyl sulfoxide, and N,N-dimethylformamide, preferably water and / or ethanol. After washing, drying and calcination are performed.
[0036] Preferably, the drying conditions include: a temperature of 80-150℃ and a time of 8-30h; more preferably, a temperature of 100-120℃ (e.g., values such as 100℃, 110℃, 115℃, and 120℃, or any range thereof) and a time of 12-24h (e.g., values such as 12h, 16h, 20h, and 24h, or any range thereof).
[0037] Preferably, the calcination conditions include: a heating rate of 1-5℃ / min, a temperature of 400-700℃, and a time of 2-8h; more preferably, a heating rate of 2-4℃ / min (e.g., values such as 2℃ / min, 3℃ / min, 3.5℃ / min, and 4℃ / min, or any range thereof), a temperature of 500-600℃ (e.g., values such as 500℃, 520℃, 550℃, and 600℃, or any range thereof), and a time of 4-6h (e.g., values such as 4h, 5h, 5.5h, and 6h, or any range thereof).
[0038] Preferably, the calcination process is carried out in a non-reactive gas atmosphere. The non-reactive gas may be selected, for example, from nitrogen and / or argon.
[0039] According to the present invention, after completing the aforementioned steps, further pulverization yields a zirconium-based catalyst that meets the requirements. Preferably, the pulverization method is ball milling, with conditions including: rotation speed 2000-5000 rpm, time 4-10 h; preferably, rotation speed 3000-4000 rpm (e.g., values such as 3000 rpm, 3200 rpm, 3600 rpm, and 4000 rpm, and any range thereof), time 6-8 h (e.g., values such as 6 h, 6.5 h, 7 h, and 8 h, and any range thereof). Controlling the particle size of the catalyst within a suitable range through ball milling can improve the performance of the absorbent. Larger particle sizes result in smaller relative surface areas and energy of the catalyst particles, while reducing particle size enhances surface activity and Brownian motion, but also leads to agglomeration, decreased dispersibility and stability, thus affecting its enhanced effect on the absorption of carbon dioxide by the composite amine liquid. Therefore, it is necessary to control the particle size of the zirconium-based catalyst within a suitable range by controlling the ball milling conditions.
[0040] According to the present invention, during the carbon dioxide absorption and desorption regeneration processes, excessively high temperatures will increase the activation energy of the catalyst particles, leading to agglomeration, while excessively low temperatures will inhibit carbon dioxide absorption. In order to minimize energy consumption while avoiding the above-mentioned adverse effects and achieving good carbon dioxide absorption and desorption regeneration rates, the contact reaction temperature is preferably 20-50°C, more preferably 30-40°C, for example, it can be 30°C, 35°C, 38°C, and 40°C, or any range between these values.
[0041] Preferably, the temperature of the thermal regeneration is 80-140℃, more preferably 100-120℃, for example, it can be 100℃, 105℃, 110℃ and 120℃ and any range between these values.
[0042] According to the present invention, in order to better cooperate with the technical solution of the present invention, the absorption tower and the regeneration tower can be selected. Preferably, the absorption tower is a bubble column. Preferably, the regeneration tower is a sieve plate tower. In the bubble column, the gas is introduced into the liquid phase through nozzles, and many small bubbles with high specific surface area are generated at the gas-liquid interface, thereby improving the gas-liquid interface area. At the same time, the zirconium-based catalyst particles can also be adsorbed on the gas-liquid interface to form a three-dimensional network structure, reducing the bubble size, increasing the liquid film thickness and bubble stiffness, thereby inhibiting the phase aggregation and coalescence of bubbles, increasing the gas-liquid mass transfer area and improving the mass transfer coefficient, which is beneficial to the carbon dioxide absorption process. Since the absorbent contains a zirconium-based catalyst, a sieve plate tower, which is more suitable for treating solid particles containing this, is selected as the regeneration tower. At the same time, the sieve plate tower also has strong corrosion resistance.
[0043] This invention employs a composite amine solution made from polyene amines and alkanolamines, combined with a zirconium-based catalyst and a mixture of nickel salt and water as the absorbent. This effectively addresses the drawbacks of polyene amines, such as high energy consumption and high corrosion rates, and further enhances carbon dioxide capture and desorption / regeneration efficiency. The absorbent strengthens mass and heat transfer rates and reduces the heat of reaction to promote carbon dioxide absorption and rich-liquid desorption / regeneration reactions. The nickel salt also acts as a heat buffer to compensate for energy loss during carbon dioxide desorption. The method of this invention offers excellent results, a simple process, low process requirements, and low cost. It requires no new equipment and can be implemented using existing equipment.
[0044] The present invention will be described in detail below through embodiments.
[0045] In the following examples, the apparatus used is conventional experimental apparatus in the field, the experimental operations and testing methods adopted are conventional operations and methods in the field, and the raw materials and reagents used are commercially available.
[0046] The operation process in each example is as follows: FCC flue gas is sent to the absorption tower to react with the absorbent to obtain a rich liquid that absorbs carbon dioxide. The rich liquid is sent to the regeneration tower for thermal regeneration to obtain a lean liquid. The lean liquid is then sent to the absorption tower for recycling.
[0047] Example 1
[0048] The FCC flue gas is FCC flue gas that has undergone desulfurization, denitrification, and dust removal treatment, with a volumetric flow rate of 100 Nm³. 3 The flow rate is 0.2 MPa per hour, and the FCC flue gas contains 20% carbon dioxide, 10% oxygen, and the remainder nitrogen. The circulation rate of the lean absorbent is 0.5 m³ / h. 3 / h. The absorption tower is a bubble column, and the regeneration tower is a sieve plate column. The contact reaction temperature in the absorption tower is 30℃, and the thermal regeneration temperature in the regeneration tower is 120℃.
[0049] The absorbent consists of 30 wt% triethylenetetramine-triethanolamine composite amine solution (the volume ratio of triethylenetetramine to triethanolamine is 1:0.2), 0.05 wt% zirconium-based catalyst, 5 wt% nickel nitrate, and the balance being water.
[0050] The zirconium-based catalyst was prepared by the following method: zirconium nitrate was dissolved in water (zirconium nitrate concentration was 40 g / L), and titanium dioxide nanoparticles (average particle size was 200 nm; the mass ratio of zirconium nitrate to titanium dioxide nanoparticles was 1:6) were added. The reaction was carried out at 90 °C for 12 h, and the reaction solution was filtered to obtain the catalyst precursor. The catalyst precursor was washed with water and dried at 100 °C for 24 h, then transferred to a tube furnace and heated to 600 °C at a heating rate of 2 °C / min under a nitrogen atmosphere, and calcined at 600 °C for 6 h. After calcination, the product was ball-milled at 3000 rpm for 8 h to obtain the zirconium-based catalyst.
[0051] Example 2
[0052] The FCC flue gas is FCC flue gas that has undergone desulfurization, denitrification, and dust removal treatment, with a volumetric flow rate of 75 Nm³. 3 The flow rate is 0.4 MPa per hour, and the FCC flue gas contains 15% carbon dioxide and 18% oxygen by volume, with the remainder being nitrogen. The circulation rate of the lean absorbent is 0.5 m³ / h. 3 / h. The absorption tower is a bubble column, and the regeneration tower is a sieve plate column. The contact reaction temperature in the absorption tower is 40℃, and the thermal regeneration temperature in the regeneration tower is 100℃.
[0053] The absorbent consists of 20 wt% tetraethylenepentamine-triisopropanolamine composite amine solution (the volume ratio of tetraethylenepentamine to triisopropanolamine is 1:0.3), 0.2 wt% zirconium-based catalyst, 3 wt% nickel sulfate, and the balance being water.
[0054] The zirconium-based catalyst was prepared by the following method: zirconium sulfate was dissolved in water (zirconia concentration 50 g / L), and alumina nanoparticles (average particle size 100 nm; zirconium sulfate to alumina nanoparticle mass ratio 1:8) were added. The reaction mixture was reacted at 80 °C for 24 h. After filtration, the catalyst precursor was obtained. The catalyst precursor was washed with ethanol and dried at 120 °C for 12 h. Then, it was transferred to a tube furnace and heated to 500 °C at a heating rate of 4 °C / min under a nitrogen atmosphere. The product was calcined at 500 °C for 8 h. After calcination, the product was ball-milled at 4000 rpm for 6 h to obtain the zirconium-based catalyst.
[0055] Example 3
[0056] The method is the same as in Example 1, except that the content of the triethylenetetramine-triethanolamine complex amine solution in the absorbent is 10 wt%.
[0057] Example 4
[0058] The method is the same as in Example 1, except that the content of the triethylenetetramine-triethanolamine complex amine solution in the absorbent is 40 wt%.
[0059] Example 5
[0060] The method is the same as in Example 1, except that the zirconium-based catalyst content in the absorbent is 0.5 wt%.
[0061] Example 6
[0062] The method is the same as in Example 1, except that the content of nickel nitrate in the absorbent is 2 wt%.
[0063] Example 7
[0064] The method is the same as in Example 1, except that the content of nickel nitrate in the absorbent is 6 wt%.
[0065] Example 8
[0066] The method is the same as in Example 1, except that the volume ratio of triethylenetetramine to triethanolamine in the triethylenetetramine-triethanolamine composite amine solution is 1:0.1.
[0067] Example 9
[0068] The method is the same as in Example 1, except that in the triethylenetetramine-triethanolamine composite amine solution, the volume ratio of triethylenetetramine to triethanolamine is 1:0.4.
[0069] Example 10
[0070] The method is the same as in Example 1, except that the volumetric flow rate of the FCC flue gas is 150 Nm³. 3 / h.
[0071] Comparative Example 1
[0072] The method is the same as in Example 1, except that a zirconium-based catalyst is not used in the absorbent.
[0073] Comparative Example 2
[0074] The method is the same as in Example 1, except that nickel nitrate is not used in the absorbent.
[0075] Comparative Example 3
[0076] The method is the same as in Example 1, except that the triethylenetetramine-triethanolamine complex amine solution is replaced with triethylenetetramine alone.
[0077] Test case
[0078] The absorption and desorption processes were performed according to the conditions in the examples above, and the cycle was repeated 5 times. The performance data after 5 cycles were statistically analyzed using conventional methods, and the data are shown in Table 1.
[0079] Table 1
[0080]
[0081] As can be seen from Table 1, Examples 1-10 using the technical solution of the present invention are superior to Comparative Examples 1-3. This demonstrates that the technical solution of the present invention achieves a good carbon dioxide recovery rate and effectively reduces energy consumption, while significantly improving the degradation of amine solution and equipment corrosion during the collection and recovery process.
[0082] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.
Claims
1. A method for capturing and recovering carbon dioxide from FCC flue gas, characterized in that, The method includes: FCC flue gas is fed to an absorption tower and reacted with the absorbent to obtain a rich liquid that absorbs carbon dioxide. The rich liquid is then fed to a regeneration tower for thermal regeneration to obtain a lean liquid. The lean liquid is then fed back to the absorption tower for recycling. The absorbent comprises 10-40 wt% of a composite amine solution, 0.01-0.5 wt% of a zirconium-based catalyst, 2-6 wt% of a nickel salt and water; the composite amine solution comprises polyene amine and alkanolamine, wherein the volume ratio of the polyene amine to the alkanolamine is 1:0.1-0.
4.
2. The method according to claim 1, wherein, The content of the composite amine solution in the absorbent is 20-30 wt%. And / or, the zirconium-based catalyst in the absorbent is present in an amount of 0.05-0.2 wt%; And / or, the content of the nickel salt in the absorbent is 3-5 wt%; And / or, the volume ratio of the polyene amine to the alkanolamine is 1:0.2-0.
3.
3. The method according to claim 1 or 2, wherein, Relative to 1m 3 The lean liquor has a circulation rate of / h, and the volumetric flow rate of the FCC flue gas is 100-300 Nm³. 3 / h, preferably 150-250Nm 3 / h; And / or, the pressure of the FCC flue gas is 0.1-0.5 MPa, preferably 0.2-0.4 MPa.
4. The method according to any one of claims 1-3, wherein, The polyene amine is selected from one or more of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine, preferably triethylenetetramine and / or tetraethylenepentamine; And / or, the alkanolamine is selected from ethanolamine, diethanolamine, triethanolamine, diethanolisopropanolamine and triisopropanolamine, preferably one or more of triethanolamine, diethanolisopropanolamine and triisopropanolamine.
5. The method according to any one of claims 1-4, wherein, The nickel salt is selected from one or more of nickel chloride, nickel sulfate, nickel nitrate and nickel carbonate, preferably nickel sulfate and / or nickel nitrate.
6. The method according to any one of claims 1-5, wherein, The method for preparing the zirconium-based catalyst includes: dissolving zirconium salt in a solvent, adding inorganic nanoparticles and reacting at high temperature to obtain a catalyst precursor, drying and calcining the catalyst precursor, and pulverizing it to obtain the zirconium-based catalyst.
7. The method according to claim 6, wherein, The solvent is selected from one or more of water, methanol, diethyl ether, acetone, acetonitrile, tetrahydrofuran, ethyl acetate, 1,4-dioxane, dimethyl sulfoxide and N,N-dimethylformamide, preferably water and / or ethanol; And / or, the zirconium salt is selected from one or more of zirconium chloride, zirconium sulfate, zirconium nitrate and zirconium carbonate, preferably zirconium sulfate and / or zirconium nitrate; And / or, the concentration of the zirconium salt in the solvent is 30-60 g / L, preferably 40-50 g / L; And / or, the inorganic nanoparticles are selected from one or more of aluminum oxide nanoparticles, titanium dioxide nanoparticles, silicon dioxide nanoparticles, magnesium oxide nanoparticles and iron oxide nanoparticles, preferably aluminum oxide nanoparticles and / or titanium dioxide nanoparticles. And / or, the average particle size of the inorganic nanoparticles is 50-300 nm, preferably 100-200 nm; And / or, the mass ratio of the zirconium salt to the inorganic nanoparticles is 1:4-10, preferably 1:6-8.
8. The method according to claim 6 or 7, wherein, The conditions for the high-temperature reaction include: temperature 70-100℃, time 8-36h; preferably, temperature 80-90℃, time 12-24h. And / or, the drying conditions include: temperature 80-150℃, time 8-30h; preferably temperature 100-120℃, time 12-24h; And / or, the conditions for the calcination treatment include: a heating rate of 1-5℃ / min, a temperature of 400-700℃, and a time of 2-8h; preferably, a heating rate of 2-4℃ / min, a temperature of 500-600℃, and a time of 4-6h. And / or, the pulverization method is ball milling, with conditions including: rotation speed 2000-5000 rpm, time 4-10 h; preferably 3000-4000 rpm, time 6-8 h.
9. The method according to any one of claims 1-8, wherein, The temperature of the contact reaction is 20-50℃, preferably 30-40℃; And / or, the temperature of the thermal regeneration is 80-140°C, preferably 100-120°C; And / or, the FCC flue gas undergoes desulfurization, denitrification, and dust removal treatment; And / or, the volume content of carbon dioxide in the FCC flue gas is 5-30%, preferably 10-20%.
10. The method according to any one of claims 1-9, wherein, The absorption tower is a bubble tower; And / or, the regeneration tower is a sieve plate tower.