Molecular sieve ion exchange method
By using room-temperature single-stage ammonium salt ion exchange and metal salt treatment, the problems of high temperature, multiple exchange cycles, high operational complexity, and poor environmental friendliness in molecular sieve ion exchange technology have been solved. This has enabled efficient and environmentally friendly molecular sieve production, improved the physical properties and catalytic activity of molecular sieves, and made them suitable for high-end petrochemical catalysis and fine chemical fields.
Patent Information
- Application Number
- CN202510882109.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-27
- Publication Date
- 2025-11-21
AI Technical Summary
Existing molecular sieve ion exchange technology suffers from drawbacks such as high temperature, numerous exchange cycles, high operational complexity, poor environmental friendliness, and insufficient catalytic performance. These drawbacks are particularly significant for ZSM-5, ZSM-11, ZSM-22, ZSM-23, ZSM-48, and SSZ-13 molecular sieves, affecting their performance and production efficiency.
A single-stage ammonium salt ion exchange method at room temperature, combined with metal salt treatment, simplifies the operation process. Using environmentally friendly ammonium salt as the exchanger, and through optimized process and equipment design, efficient ion exchange of molecular sieves is achieved, avoiding damage to the molecular sieve structure caused by high temperature and improving catalytic activity.
It significantly reduces energy consumption and production costs, improves production efficiency, simplifies operation processes, reduces environmental pollution, enhances the physical and chemical properties of molecular sieves, and strengthens catalytic activity and product quality stability. It is suitable for high-end petrochemical catalysis and fine chemical fields.
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Figure CN120984356A_ABST
Abstract
Description
Technical Field
[0001] This application relates to a molecular sieve ion exchange method, belonging to the field of molecular sieve synthesis post-processing technology. Background Technology
[0002] In the production of molecular sieves, ion exchange is an essential post-processing step. Its main purpose is to adjust the molecular sieve's acid-base properties, pore size, pore volume, specific surface area, and elemental composition to meet the needs of different industrial applications. For example, in the catalytic cracking process in the petrochemical industry, molecular sieves need to undergo ion exchange to remove sodium and potassium ions, thereby improving the activity and selectivity of the molecular sieve catalyst.
[0003] In the selection of exchange resins, existing methods mainly use strong acid exchange resins such as sulfuric acid and hydrochloric acid. Although these strong acids are effective in ion exchange, they bring serious safety and environmental problems. For example, the use of sulfuric acid and hydrochloric acid poses operational risks, and the wastewater generated after ion exchange contains a large amount of acidic substances, which is difficult and costly to treat. If not properly treated, direct discharge will cause serious pollution to the ecological environment such as soil and water bodies, which is inconsistent with the current concept of green chemistry and sustainable development. In addition, the use of strong acid exchange resins can easily damage the crystal structure of molecular sieves, reduce crystallinity and the content of metals such as aluminum, and cause "dealuminization" or "demetallization" during exchange, thereby reducing important parameters of molecular sieves such as acid strength, acid quantity, pore volume, and specific surface area.
[0004] To address these issues, researchers are currently focusing on using ammonium salts for ion exchange, aiming to overcome the problems associated with strong acid exchangers. However, the ammonium salt ion exchange process still faces numerous unresolved challenges.
[0005] 1. From a temperature perspective, the ammonium salt ion exchange method requires relatively high temperatures.
[0006] For example, in some industrial-scale ion exchange processes, the temperature often needs to be maintained between 60 and 120°C. High-temperature conditions not only require additional heating equipment and energy consumption, increasing production costs, but may also damage the crystal structure of molecular sieves, thereby affecting their performance.
[0007] 2. In terms of the number of exchanges, in order to achieve the expected levels of sodium (Na) ion and potassium (K) ion content, multiple exchange operations using ammonium salts are often required.
[0008] Repeated exchanges of ammonium salts not only prolong the production cycle and reduce production efficiency, but each exchange process is also accompanied by material loss and increased processing costs. Since most ammonium salt solutions are acidic, repeated exchanges can also cause some damage to the molecular sieve structure.
[0009] 3. High degree of complexity in operation
[0010] High-temperature calcination is required before and after the two exchanges. Repeated calcination can easily lead to the collapse of the molecular sieve structure, and a decrease in crystallinity, pore volume, specific surface area, acid strength and acid content.
[0011] 4. High operational requirements and high risk of error.
[0012] Traditional processes may also involve complex equipment assembly, material addition sequence, and strict control of reaction temperature and time, which requires high professional skills from operators and increases the risk of human error in the production process.
[0013] Compared to other molecular sieves with low silica-to-alumina ratios, ZSM-5, ZSM-11, ZSM-22, ZSM-23, ZSM-48, and SSZ-13 molecular sieves have relatively smaller pore sizes and slower mass transfer rates. Therefore, these problems become more pronounced when ammonium salts undergo ion exchange treatment.
[0014] In summary, existing molecular sieve ion exchange technologies have significant drawbacks in terms of temperature, number of exchange cycles, operational complexity, environmental friendliness of the exchanger, and catalytic performance. There is an urgent need for a novel ion exchange method for six molecular sieves: ZSM-5, ZSM-11, ZSM-22, ZSM-23, ZSM-48, and SSZ-13, to address these issues. Summary of the Invention
[0015] To address the aforementioned issues, a molecular sieve ion exchange method is provided. This method employs specific ion exchange treatments on six particular molecular sieves, which can reduce environmental pollution, save operation time, and improve the product quality and catalytic activity of the molecular sieves, facilitating their industrial application.
[0016] This application provides a molecular sieve ion exchange method, comprising the following steps:
[0017] (1) The molecular sieve after removing the organic template agent is dried to constant weight, wherein the molecular sieve is selected from at least one of ZSM-5 molecular sieve, ZSM-11 molecular sieve, ZSM-22 molecular sieve, ZSM-23 molecular sieve, ZSM-48 molecular sieve, and SSZ-13 molecular sieve;
[0018] (2) The dried molecular sieve is added to the ammonium salt solution and ion exchange is carried out at 20-30℃ for 0.5-3h;
[0019] (3) The molecular sieve obtained above is separated, dried and activated to obtain the final product.
[0020] The ion exchange method of this application is designed for the aforementioned six specific types of molecular sieves. Treating these six molecular sieves with the aforementioned ion exchange method offers the following advantages:
[0021] (1) Reduced Energy Consumption: Traditional high-temperature ion exchange processes require maintaining a reaction temperature of 60–120°C, resulting in significant costs in terms of heating equipment operation and energy consumption. Traditional processes generally employ high-temperature ion exchange, and those skilled in the art generally believe that low-temperature exchange is ineffective, rarely considering low-temperature exchange methods. This application breaks through the limitations of traditional high-temperature exchange by employing exchange at room temperature under specific conditions, eliminating the need for additional heating equipment to maintain a high-temperature environment and directly reducing energy consumption. For example, a medium-sized molecular sieve production enterprise performing thousands of ion exchange operations annually can save a significant amount of electricity or steam energy using this method, amounting to hundreds of thousands of yuan in economic costs, effectively reducing production costs.
[0022] (2) Simplified Operation and Increased Efficiency: Traditional processes involve complex equipment assembly, material addition sequences, and multiple exchange operations, resulting in long production cycles and cumbersome operations. This invention optimizes the process, requiring only one exchange to achieve the required K and Na ion content, with relatively simple operation steps, significantly shortening the production cycle. A single ammonium salt exchange process takes only 0.5–3 hours; including pre- and post-processing time, efficiency is greatly improved compared to the several days required by traditional multiple exchanges. This not only allows companies to produce more products in the same amount of time, increasing capacity, but also reduces the time and effort required for manual operation, lowering labor costs. Simultaneously, the simplified operation process reduces the possibility of human error, improving product quality stability.
[0023] (3) Environmental Advantages: This invention uses environmentally friendly ammonium salts as the exchange medium, completely eliminating strong acid exchange mediums such as sulfuric acid and hydrochloric acid. Wastewater generated by using sulfuric acid and hydrochloric acid contains heavy metal ions and strong acidic substances, making treatment costly and difficult. In contrast, the wastewater generated after ammonium salt exchange is relatively easy to purify using conventional methods such as biochemical treatment. For example, after simple aeration and sedimentation, the wastewater can meet discharge standards, greatly reducing the wastewater treatment pressure and environmental costs for enterprises. This is of great significance for the entire molecular sieve production industry to develop in a green and sustainable direction, conforming to current global requirements for environmental protection and sustainable development, and helping enterprises establish a good social image and enhance market competitiveness.
[0024] (4) Improved Product Quality: On the one hand, room-temperature ammonium salt exchange avoids the potential damage to the molecular sieve crystal structure caused by high temperatures. This allows the molecular sieve to not only maintain its original excellent physical and chemical properties, such as crystallinity, acid strength and amount, pore size distribution, pore volume, and specific surface area, but also to improve these properties to a certain extent. On the other hand, the precisely controlled primary exchange process of ammonium salts allows for more accurate adjustment of the ionic composition in the molecular sieve, making the product quality more stable and controllable. This provides more reliable products for applications with extremely high molecular sieve performance requirements, such as high-end petrochemical catalysis and fine chemicals, helping to improve the production efficiency and product quality of related industries.
[0025] (5) Enhanced catalytic activity: By reacting the molecular sieve with nickel salt, cobalt salt, and copper salt after the ammonium salt exchange, a molecular sieve with good catalytic activity can be directly obtained. Compared with the traditional impregnation method for loading nickel salt, cobalt salt, and copper salt, the catalytic activity of the molecular sieve can be significantly improved.
[0026] Optionally, the concentration of the ammonium salt solution in step (2) is 0.5–2 mol / L;
[0027] The solid-liquid mass ratio of the molecular sieve to the ammonium salt solution is 1:(5-10).
[0028] The aforementioned ammonium salt dosage, combined with room-temperature ion exchange conditions, synergistically improves the efficiency of ion exchange on molecular sieves. This allows for achieving the required K and Na ion content with a single room-temperature exchange, significantly enhancing efficiency. However, if the ammonium salt concentration is too high, the pH of the ammonium salt solution will decrease, causing dealuminization of the molecular sieve during ion exchange and leading to structural damage, making it difficult to maintain basic catalytic performance. Conversely, if the ammonium salt concentration is too low or the solid-liquid mass ratio is too high, insufficient ammonium salt dosage will hinder effective ion exchange on the molecular sieve, resulting in insufficient K and Na ion content.
[0029] Optionally, the ammonium salt in step (2) is selected from at least one of ammonium nitrate, ammonium chloride, ammonium sulfate, ammonium oxalate, ammonium phosphate, ammonium bicarbonate, ammonium carbonate, and ammonium acetate, preferably ammonium bicarbonate or ammonium carbonate.
[0030] Ammonium bicarbonate and ammonium carbonate produce wastewater that is easier to treat than other ammonium salts, better meets the standards of industrialized environmentally friendly production, and is easier to promote and use.
[0031] Optionally, the stirring speed in step (2) is 100 to 300 rpm to fully disperse the molecular sieve in the ammonium salt solution, ensuring that each molecular sieve particle can fully contact the ammonium salt solution, further improving the ion exchange efficiency and saving operation time.
[0032] The applicant also found that current molecular sieves used in the catalytic hydrogenation of hydrocarbon-based biodiesel to produce biojet fuel require loading with metals such as nickel, cobalt, and copper. However, traditional loading methods (such as impregnation) have drawbacks such as uneven dispersion of active components, concentration of active components on the outer surface of the molecular sieve, and easy formation of bulk metal oxide components with low activity and low selectivity. As a result, the catalytic activity and selectivity of metal-loaded molecular sieves are not high, and the yield of biojet fuel is low.
[0033] Optionally, step (3) may be preceded by the following step:
[0034] After separating, washing and drying the molecular sieve from step (2), it is placed in a metal salt solution and treated at 20-80°C for 0.5-3 hours. The metal salt is selected from at least one of nickel salt, cobalt salt and copper salt.
[0035] This application further obtains molecular sieves with good catalytic activity directly by reacting them with metal salts after ammonium salt exchange. Compared with the traditional method of loading metal salts, this significantly improves the catalytic activity and selectivity of the molecular sieves. Furthermore, it fully utilizes the pore effect, specific surface area, and pore volume of the molecular sieves to improve the dispersion and uniformity of the metal active components, achieving a synergistic catalytic effect between the acid centers and the metal active centers of the molecular sieves.
[0036] The above treatment method is more suitable for ZSM-22 molecular sieve, ZSM-23 molecular sieve, and ZSM-48 molecular sieve, which have better catalytic effects on the hydrogenation of hydrocarbon-based biodiesel to produce biojet fuel.
[0037] Optionally, the concentration of metal ions in the metal salt solution is 0.5–2 mol / L, and the solid-liquid mass ratio of the molecular sieve to the metal salt solution is 1:(5–10).
[0038] The excessive use of nickel, cobalt, and copper salts resulted in an excess of these salts being unable to participate in the exchange process. This excess salt was washed away during subsequent water washing, leading to increased costs and difficulties in wastewater treatment.
[0039] Optionally, the metal salt is selected from nickel salt and cobalt salt, and the molar ratio of nickel ions to cobalt ions in the metal salt solution is 1:(0.2-1).
[0040] For the specific catalytic reaction of hydrogenating hydrocarbon-based biodiesel to produce biojet fuel, the amount of nickel ions in the metal salt must be no less than that of cobalt ions. This is because nickel is the main catalyst and cobalt is the co-catalyst in this reaction. Under the aforementioned ratio, treating the molecular sieve allows cobalt to better assist nickel in catalysis, resulting in a higher biojet fuel yield. If the proportion of cobalt ions is too high, the co-catalyst becomes dominant, leading to a decrease in the amount of the main catalyst. Furthermore, cobalt becomes less effective at assisting nickel in catalysis, thus reducing the biojet fuel yield.
[0041] Optionally, the nickel salt is selected from at least one of nickel chloride, nickel nitrate, nickel sulfate, and nickel acetate.
[0042] Optionally, the cobalt salt is selected from at least one of cobalt chloride, cobalt nitrate, cobalt sulfate, and cobalt acetate.
[0043] Optionally, the copper salt is selected from at least one of copper chloride, copper nitrate, copper sulfate, and copper acetate.
[0044] Optionally, the drying temperature in step (1) is 100-120°C and the drying time is 2-4 hours.
[0045] The drying process in step (1) can reduce the influence of residual moisture in the molecular sieve, fully release the ion exchange sites in the molecular sieve, improve the ion exchange efficiency and ion exchange effect, and also eliminate impurities.
[0046] Optionally, the separation in step (3) can be achieved by using filtration or centrifugation equipment to separate the molecular sieve from the solution, such as a plate and frame filter press, a vacuum filtration device, or a high-speed centrifuge. During filtration or centrifugation, it is important to ensure that the filtration or centrifugation speed is moderate to avoid the loss of molecular sieve particles through the filter cloth due to excessively fast filtration or centrifugation speed, or to avoid affecting production efficiency due to excessively slow filtration or centrifugation speed. Generally, the filtration or centrifugation time is controlled between 0.5 and 2 hours to ensure sufficient solid-liquid separation.
[0047] Optionally, in step (3), the molecular sieve is rinsed multiple times with deionized water, with each rinse using 3 to 5 times the mass of the molecular sieve. The washing process can be carried out by rinsing, soaking and stirring followed by filtration or centrifugation to ensure the removal of residual ammonium salt solution and exchanged sodium and potassium ions from the surface of the molecular sieve. The number of washes is generally 3 to 5 times. After each wash, the conductivity of the washing solution is measured. When the conductivity decreases to a certain value (e.g., less than 100 μS / cm), the washing is considered qualified.
[0048] Optionally, the drying temperature in step (3) is 80-100℃ and the drying time is 4-6h.
[0049] The drying in step (3) is used to remove residual moisture from the molecular sieve. During the drying process, the molecular sieve can be turned over periodically to ensure even heating and accelerate the drying speed.
[0050] Optionally, the activation temperature in step (3) is 400-600℃ and the activation time is 2-4h.
[0051] Step (3) involves activating the dried molecular sieve to restore and enhance its post-ion exchange properties. During the activation process, the internal structure of the molecular sieve is further adjusted, and ammonium ions decompose into ammonia gas, thereby forming more acidic sites and improving the acidity and other properties of the molecular sieve.
[0052] The beneficial effects of this application include, but are not limited to:
[0053] 1. The molecular sieve ion exchange method according to this application has the advantages of effectively reducing energy consumption, simplifying operation process, improving product and catalytic activity, improving production efficiency and being environmentally friendly, and has great economic and environmental benefits.
[0054] 2. The molecular sieve ion exchange method of this application can improve the physical, chemical and catalytic properties of molecular sieves, and enhance the quality stability and controllability of molecular sieves, while reducing operational difficulty and environmental pollution.
[0055] 3. The molecular sieve ion exchange method of this application reduces the production cycle, improves the production efficiency of molecular sieves, increases production capacity, and at the same time, the reasonable design of the reaction process and the selection of appropriate equipment simplify the operation process, reduce the difficulty of operation, reduce the possibility of human error, and improve the stability of product quality.
[0056] 4. According to the molecular sieve ion exchange method of this application, the molecular sieve is innovatively treated by a single ammonium salt exchange method at room temperature. This treatment method breaks with conventional understanding and can achieve the required content of K ions and Na ions, thus greatly improving production efficiency.
[0057] 5. The molecular sieve ion exchange method according to this application not only enables the concentrations of K and Na ions to meet the standards, but also increases the relative crystallinity of the molecular sieve by more than 13%, the specific surface area by more than 8%, and the pore volume by more than 7%. When further exchanged with metal salts, a highly efficient catalyst for the catalytic production of biojet fuel from hydrocarbon-based biodiesel hydrogenation can be obtained. Compared with the supported catalyst obtained by the widely used equal-volume impregnation method, the conversion rate and yield of biojet fuel are significantly improved. Attached Figure Description
[0058] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:
[0059] Figure 1The images shown are XRD patterns of the molecular sieve before and after ion exchange in Example 1 of this application. Detailed Implementation
[0060] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.
[0061] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application were all purchased commercially.
[0062] Unless otherwise specified, the methods used in the embodiments and comparative examples of this application are conventional methods in the prior art. The initial specific surface area of the ZSM-5 molecular sieve used in the following embodiments and comparative examples is 337 m². 2 / g, initial pore volume is 0.18cm 3 / g; The initial specific surface area of ZSM-11 molecular sieve is 350m². 2 / g, initial pore volume is 0.25cm³ 3 / g; The initial specific surface area of ZSM-22 molecular sieve is 160m². 2 / g, initial pore volume is 0.12cm³ 3 / g; The initial specific surface area of ZSM-23 molecular sieve is 228m². 2 / g, initial pore volume is 0.21cm 3 / g; The initial specific surface area of ZSM-48 molecular sieve is 375m². 2 / g, initial pore volume is 0.26cm³ 3 / g; The initial specific surface area of SSZ-13 molecular sieve is 550m². 2 / g, initial pore volume is 0.30cm³ 3 / g.
[0063] Example 1
[0064] This embodiment relates to a molecular sieve ion exchange method, including the following steps:
[0065] (1) Dry the ZSM-22 molecular sieve at 120℃ for 2 hours until constant weight;
[0066] (2) The dried molecular sieve was added to the ammonium nitrate solution with a concentration of 1 mol / L and a solid-liquid mass ratio of 1:8 between the molecular sieve and the ammonium nitrate solution. Ion exchange was carried out at 25℃ for 2 h.
[0067] (3) The molecular sieve obtained above is separated by a vacuum filter, washed 5 times with 5 times the mass of the molecular sieve with deionized water, dried at 90°C for 5 hours, and finally activated at 500°C for 3 hours to obtain the final product.
[0068] Example 2
[0069] This embodiment relates to a molecular sieve ion exchange method, including the following steps:
[0070] (1) Dry the ZSM-11 molecular sieve at 120℃ for 2 hours until constant weight;
[0071] (2) The dried molecular sieve was added to the ammonium chloride solution with a concentration of 0.5 mol / L and a solid-liquid mass ratio of 1:10 between the molecular sieve and the ammonium chloride solution. Ion exchange was carried out at 20℃ for 3 h.
[0072] (3) The molecular sieve obtained above is separated by a plate and frame filter press, washed 5 times with deionized water at a mass of 3 times that of the molecular sieve, dried at 80°C for 6 hours, and finally activated at 400°C for 2 hours to obtain the final product.
[0073] Example 3
[0074] This embodiment relates to a molecular sieve ion exchange method, including the following steps:
[0075] (1) Dry the ZSM-5 molecular sieve at 100℃ for 4 hours until constant weight;
[0076] (2) The dried molecular sieve was added to the ammonium sulfate solution with a concentration of 2 mol / L and a solid-liquid mass ratio of 1:5 between the molecular sieve and the ammonium salt solution. Ion exchange was carried out at 30℃ for 0.5 h.
[0077] (3) The molecular sieve obtained above is separated by centrifugation, washed three times with five times the mass of deionized water, dried at 100℃ for 4 hours, and finally activated at 600℃ for 2 hours to obtain the final product.
[0078] Example 4
[0079] This embodiment relates to a molecular sieve ion exchange method, including the following steps:
[0080] (1) Dry the ZSM-23 molecular sieve at 120℃ for 2 hours until constant weight;
[0081] (2) The dried molecular sieve was added to the ammonium phosphate solution with a concentration of 0.8 mol / L and a solid-liquid mass ratio of 1:7 between the molecular sieve and the ammonium phosphate solution. Ion exchange was carried out at 22℃ for 2.5 h.
[0082] (3) The molecular sieve obtained above is separated by centrifugation, washed 4 times with deionized water at a mass of 4 times that of the molecular sieve, dried at 85°C for 5.5 h, and finally activated at 550°C for 3 h to obtain the final product.
[0083] Example 5
[0084] This embodiment relates to a molecular sieve ion exchange method, including the following steps:
[0085] (1) Dry ZSM-48 molecular sieve at 100℃ for 4 hours until constant weight;
[0086] (2) The dried molecular sieve was added to the ammonium carbonate solution with a concentration of 1.5 mol / L and a solid-liquid mass ratio of 1:5 between the molecular sieve and the ammonium carbonate solution. Ion exchange was carried out at 30℃ for 1 h.
[0087] (3) The molecular sieve obtained above is separated by centrifugation, washed three times with five times the mass of deionized water, dried at 90℃ for 5h, and finally activated at 520℃ for 3h to obtain the final product.
[0088] Example 6
[0089] This embodiment relates to a molecular sieve ion exchange method, including the following steps:
[0090] (1) Dry the SSZ-13 molecular sieve at 110℃ for 3 hours until constant weight;
[0091] (2) The dried molecular sieve was added to the ammonium acetate solution with a concentration of 1.1 mol / L and a solid-liquid mass ratio of 1:8 between the molecular sieve and the ammonium acetate solution. Ion exchange was carried out at 25°C for 2 hours.
[0092] (3) The molecular sieve obtained above is separated by centrifugation, washed 5 times with 5 times the mass of deionized water, dried at 95℃ for 4.5h, and finally activated at 580℃ for 2.5h to obtain the final product.
[0093] Example 7
[0094] The difference between this embodiment and Example 1 is that the concentration of the ammonium nitrate solution is 2.5 mol / L.
[0095] Example 8
[0096] The difference between this embodiment and Embodiment 1 is that the solid-liquid mass ratio of the molecular sieve to the ammonium nitrate solution is 1:4.
[0097] Example 9
[0098] The difference between this embodiment and Embodiment 1 is that ammonium bicarbonate is used instead of ammonium nitrate.
[0099] Example 10
[0100] The difference between this embodiment and embodiment 1 is that steps (1) and (2) remain unchanged;
[0101] (3) The molecular sieve obtained above was separated by a vacuum filter, washed 5 times with 5 times the mass of the molecular sieve in deionized water, and then dried at 90°C for 5 hours.
[0102] (4) The dried molecular sieve was placed in a nickel nitrate solution with a nickel ion concentration of 1.0 mol / L and a solid-liquid mass ratio of 1:7 between the molecular sieve and the nickel nitrate solution, and treated at 40°C for 2.5 h.
[0103] (5) The molecular sieve obtained above is separated by a vacuum filter, washed 5 times with 5 times the mass of the molecular sieve in deionized water, dried at 90°C for 5 hours, and finally activated at 500°C for 3 hours to obtain the final product.
[0104] Example 11
[0105] The difference between this embodiment and embodiment 10 is that the molecular sieve from step (4) is placed in a cobalt chloride solution with a cobalt ion concentration of 0.5 mol / L and a solid-liquid mass ratio of 1:5 between the molecular sieve and the cobalt chloride solution, and treated at 80°C for 0.5 h.
[0106] Example 12
[0107] The difference between this embodiment and embodiment 10 is that the molecular sieve from step (4) is placed in a copper sulfate solution with a copper ion concentration of 1.0 mol / L and a solid-liquid mass ratio of 1:10 between the molecular sieve and the copper sulfate solution, and is treated at 20°C for 3 hours.
[0108] Example 13
[0109] The difference between this embodiment and embodiment 10 is that the molecular sieve in step (4) is placed in a mixed solution of nickel nitrate and cobalt chloride, the concentration of nickel ions in the mixed solution is 1.0 mol / L, the concentration of cobalt ions is 0.2 mol / L, and the solid-liquid mass ratio of the molecular sieve to the mixed solution is 1:7.
[0110] Example 14
[0111] The difference between this embodiment and Embodiment 13 is that the concentration of cobalt ions is 1.0 mol / L.
[0112] Example 15
[0113] The difference between this embodiment and Embodiment 13 is that the concentration of cobalt ions is 1.2 mol / L.
[0114] Example 16
[0115] In this embodiment, the molecular sieve obtained in Example 1 is loaded into a nickel nitrate solution with a nickel ion concentration of 1.0 mol / L by an equal-volume impregnation method.
[0116] Comparative Example 1
[0117] The difference between this comparative example and Example 1 is that the temperature of ion exchange in step (2) is 60°C.
[0118] Comparative Example 2
[0119] The difference between this comparative example and Example 1 is that after step (3) is completed, steps (2) and (3) are performed again, that is, two ion exchanges are performed.
[0120] Comparative Example 3
[0121] The difference between this comparative example and Example 10 is that steps (2) and (3) are omitted, and steps (4) and (5) are performed directly.
[0122] Test Example 1
[0123] The K and Na ion contents of the molecular sieves prepared in the above examples and comparative examples were tested, and the specific results are shown in Table 1. In Table 1, "-" indicates that the substance was not detected.
[0124] The specific method for testing the K and Na ion content is as follows: determination by X-ray fluorescence spectrometry (XRF).
[0125] Table 1
[0126]
[0127]
[0128] Test Example 2
[0129] The relative crystallinity, specific surface area, and pore volume of the molecular sieves before and after preparation in the above embodiments and comparative examples were tested. The change rate of relative crystallinity, specific surface area, and pore volume of the molecular sieve after preparation compared with the molecular sieve before preparation was calculated. The specific results are shown in Table 2.
[0130] The relative crystallinity change rate = [(relative crystallinity of the molecular sieve after treatment - relative crystallinity of the initial molecular sieve) / relative crystallinity of the initial molecular sieve] * 100%. A relative crystallinity change rate greater than 0 indicates that the relative crystallinity of the molecular sieve increases after ion exchange, while a relative crystallinity change rate less than 0 indicates that the relative crystallinity of the molecular sieve decreases after ion exchange.
[0131] Specific surface area change rate = [(specific surface area of the molecular sieve after treatment - specific surface area of the initial molecular sieve) / specific surface area of the initial molecular sieve] * 100%. A specific surface area change rate greater than 0 indicates that the specific surface area of the molecular sieve increases after ion exchange, while a specific surface area change rate less than 0 indicates that the specific surface area of the molecular sieve decreases after ion exchange.
[0132] The pore volume change rate is calculated as follows: [(pore volume of the molecular sieve after treatment - pore volume of the initial molecular sieve) / pore volume of the initial molecular sieve] * 100%. A pore volume change rate greater than 0 indicates that the pore volume of the molecular sieve increases after ion exchange, while a pore volume change rate less than 0 indicates that the pore volume of the molecular sieve decreases after ion exchange.
[0133] The specific methods for testing relative crystallinity, specific surface area, and pore volume are as follows:
[0134] The relative crystallinity was determined by X-ray diffraction (XRD). The relative crystallinity is calculated as: (sum of the relative intensities of the main characteristic peaks of the molecular sieve sample in the XRD spectrum / sum of the relative intensities of the main characteristic peaks of the reference molecular sieve sample in the XRD spectrum) * 100%.
[0135] Specific surface area and pore volume were determined using a nitrogen physical adsorption analyzer.
[0136] Figure 1 The XRD patterns of the molecular sieve in Example 1 before and after ammonium salt ion exchange are shown in the figure. It can be seen from the figure that the XRD diffraction peak of ZSM-22 molecular sieve after ammonium nitrate ion exchange is significantly enhanced, and the relative crystallinity calculated based on the XRD diffraction peak intensity is also increased. This indicates that the room temperature ion exchange method of the present invention can significantly improve the crystallinity of molecular sieve.
[0137] Table 2
[0138]
[0139] Test Example 3
[0140] The molecular sieve catalysts prepared in Examples 10-16 and Comparative Example 3 were pre-reduced in situ online in a fixed-bed reactor.
[0141] The reduced molecular sieve catalyst was used in the catalytic hydrogenation of hydrocarbon-based biodiesel to produce bio-jet fuel. Specific operating conditions were: reaction temperature 280℃, hydrogen pressure 4 MPa, hydrogen to hydrocarbon-based biodiesel volume ratio (hydrogen-to-oil ratio) 1000, and mass hourly space velocity (HHSV) 2.0 h⁻¹. -1 .
[0142] The conversion rate of hydrocarbon-based biodiesel, the yield of biojet fuel, and the freezing point of biojet fuel in the above-mentioned process of hydrogenating hydrocarbon-based biodiesel to biojet fuel were tested. The specific test results are shown in Table 3. The biojet fuel prepared using the molecular sieve catalysts in the following examples and comparative examples all had freezing points below -40℃, proving that the reaction products meet the requirements for use as biojet fuel.
[0143] Table 3
[0144] Test number Hydrocarbon-based biodiesel conversion rate (%) Bio-jet fuel yield (%) Example 10 73.4 62.1 Example 11 56.2 31.8 Example 12 43.9 26.1 Example 13 76.4 67.9 Example 14 73.5 45.7 Example 15 58.2 35.2 Example 16 42.8 37.0 Comparative Example 3 45.8 46.8
[0145] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.
Claims
1. A molecular sieve ion exchange method, characterized in that, Includes the following steps: (1) The molecular sieve after removing the organic template agent is dried to constant weight, wherein the molecular sieve is selected from at least one of ZSM-5 molecular sieve, ZSM-11 molecular sieve, ZSM-22 molecular sieve, ZSM-23 molecular sieve, ZSM-48 molecular sieve, and SSZ-13 molecular sieve; (2) The dried molecular sieve is added to the ammonium salt solution and ion exchange is carried out at 20-30℃ for 0.5-3h; (3) The molecular sieve obtained above is separated, washed, dried and activated to obtain the final product.
2. The molecular sieve ion exchange method according to claim 1, characterized in that, The concentration of the ammonium salt solution in step (2) is 0.5–2 mol / L; The solid-liquid mass ratio of the molecular sieve to the ammonium salt solution is 1:(5-10).
3. The molecular sieve ion exchange method according to claim 1, characterized in that, The ammonium salt mentioned in step (2) is selected from at least one of ammonium nitrate, ammonium chloride, ammonium sulfate, ammonium oxalate, ammonium phosphate, ammonium bicarbonate, ammonium carbonate, and ammonium acetate.
4. The molecular sieve ion exchange method according to claim 1, characterized in that, Step (3) is preceded by the following steps: After separating, washing and drying the molecular sieve from step (2), it is placed in a metal salt solution and treated at 20-80°C for 0.5-3 hours. The metal salt is selected from at least one of nickel salt, cobalt salt and copper salt.
5. The molecular sieve ion exchange method according to claim 4, characterized in that, The concentration of metal ions in the metal salt solution is 0.5–2 mol / L, and the solid-liquid mass ratio of the molecular sieve to the metal salt solution is 1:(5–10).
6. The molecular sieve ion exchange method according to claim 4, characterized in that, The metal salt is selected from nickel salt and cobalt salt, and the molar ratio of nickel ions to cobalt ions in the metal salt solution is 1:(0.2~1).
7. The molecular sieve ion exchange method according to claim 1, characterized in that, The nickel salt is selected from at least one of nickel chloride, nickel nitrate, nickel sulfate, and nickel acetate.
8. The molecular sieve ion exchange method according to claim 1, characterized in that, The cobalt salt is selected from at least one of cobalt chloride, cobalt nitrate, cobalt sulfate, and cobalt acetate.
9. The molecular sieve ion exchange method according to claim 1, characterized in that, The copper salt is selected from at least one of copper chloride, copper nitrate, copper sulfate, and copper acetate.
10. The molecular sieve ion exchange method according to claim 1, characterized in that, The activation temperature in step (3) is 400-600℃, and the activation time is 2-4h.