Liquefied petroleum gas alkylation reaction catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of catalysts, and discloses a liquefied petroleum gas alkylation reaction catalyst and a preparation method and application thereof, the catalyst comprises, by mass, 80%-95% of a ZMQ-1 molecular sieve, 0.5%-5% of transition metal and 5%-10% of a binder. The preparation method of the catalyst comprises the following steps: firstly, synthesizing a ZMQ-1 molecular sieve through a hydrothermal synthesis method, then dipping the ZMQ-1 molecular sieve in a solution containing rare earth metal and a group VIII metal salt, then drying the dipped molecular sieve, then calcining the dried catalyst, finally mixing with a binder, and carrying out wet granulation to obtain the catalyst. And drying and screening to obtain the final catalyst. By optimizing the aperture, the specific surface area, the metal loading capacity, the liquid-gas ratio, the reaction time and the like of the molecular sieve, the conversion rate, the activity, the selectivity and the stability of the catalyst are remarkably improved, the service life is prolonged, and the regeneration capacity is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and particularly to a catalyst for liquefied petroleum gas alkylation reaction, its preparation method and application. Background Art

[0002] The liquefied petroleum gas (LPG) alkylation reaction is one of the important catalytic reactions in the petrochemical industry. This reaction alkylates light hydrocarbons such as propylene and butene with isomerized alkanes to produce more economically valuable high-alkane products. Since the LPG alkylation reaction requires relatively high catalytic activity and selectivity, the choice and performance of the catalyst are crucial for the efficiency and effect of the reaction.

[0003] Currently, mesoporous molecular sieve catalysts are widely used in the LPG alkylation reaction. Due to their relatively large specific surface area and good pore structure, they can theoretically provide abundant acidic sites, thus effectively promoting the reaction. However, the existing mesoporous molecular sieve catalysts still face some challenges. First, many traditional mesoporous molecular sieve catalysts have a relatively small mesopore volume, resulting in difficulty for reactant molecules to fully enter the pores of the catalyst, thereby limiting their catalytic efficiency. Second, the density of acidic sites in the existing catalysts is relatively low, making it difficult to meet the relatively high acidic environment required in the alkylation reaction, which in turn leads to a decrease in the activity of the catalyst and poor reaction selectivity. Moreover, during the long-term reaction process, due to the accumulation of reactants or by-products on the surface of the catalyst, it is easy to cause phenomena such as carbon deposition and pore blockage on the catalyst. This not only reduces the reactivity of the catalyst but also affects the long-term stability of the catalyst and reduces its renewability.

[0004] Therefore, how to solve the problems of small mesopore volume, low acidic sites, and easy blockage of the existing mesoporous molecular sieve catalysts, and improve the activity, stability, and reusability of the liquefied petroleum gas alkylation reaction catalyst has become an important topic in the current catalyst research and development field. Summary of the Invention

[0005] In view of the deficiencies of the prior art, the present invention provides a catalyst for liquefied petroleum gas alkylation reaction, its preparation method and application, which solve the problems of small mesopore volume, low acidic sites, and easy blockage of the existing mesoporous molecular sieve catalysts in the liquefied petroleum gas alkylation reaction.

[0006] To achieve the above objectives, the present invention is realized through the following technical solutions: A catalyst for liquefied petroleum gas alkylation reaction, calculated by mass percentage, comprises the following components:

[0007] ZMQ-1 molecular sieve, with a mass proportion in the catalyst of 80%-95%;

[0008] Transition metal, with a mass proportion in the catalyst of 0.5%-5%;

[0009] A binder, with a mass proportion in the catalyst being 5%-10%;

[0010] Wherein, the transition metal is at least one of rare earth metals and Group VIII metals.

[0011] Preferably, the specific surface area of the ZMQ-1 molecular sieve is 300-500 m 2 / g, and its mesopore diameter is 2-3 nm.

[0012] Preferably, the rare earth metal is at least one of cerium and yttrium, the Group VIII metal is at least one of molybdenum and tungsten, and the loading amount of the transition metal is 0.5-5% by mass ratio.

[0013] Preferably, the raw materials of the ZMQ-1 molecular sieve include sodium silicate, sodium aluminate, and cetyltrimethylammonium bromide.

[0014] Preferably, the binder is bauxite or diatomite.

[0015] The second aspect of the present invention provides a preparation method of the above-mentioned liquefied petroleum gas alkylation reaction catalyst, including the following steps:

[0016] S1. Synthesize the ZMQ-1 molecular sieve. The ZMQ-1 molecular sieve is prepared by hydrothermal synthesis. The hydrothermal synthesis conditions are that the reaction temperature is 100-160 °C, the reaction time is 24-72 h, and the reaction pressure is 0.5-2 MPa;

[0017] S2. Immerse the ZMQ-1 molecular sieve in a solution containing rare earth metals and Group VIII metal salts;

[0018] S3. Dry the impregnated ZMQ-1 molecular sieve. The drying temperature is 100-120 °C, and the drying time is 8-12 h;

[0019] S4. Calcinate the dried catalyst. The calcination temperature is 450-600 °C, and the calcination time is 4-6 h;

[0020] S5. Mix the calcined catalyst with the binder and perform wet granulation to obtain catalyst particles with a particle size of 1-5 mm;

[0021] S6. Dry and screen the catalyst particles to obtain the final catalyst.

[0022] Preferably, the metal salts used in the solution in step S2 are at least one of cerium chloride and ammonium molybdate, and the concentration of the metal salts is 0.1 to 1.0 mol / L.

[0023] Preferably, in the step S2, the impregnation time is 2 - 12 h and the impregnation temperature is 25 - 50 °C.

[0024] The third aspect of the present invention provides a method for applying the liquefied petroleum gas alkylation reaction catalyst. The catalyst is used in the liquefied petroleum gas alkylation reaction, with a reaction temperature of 200 - 400 °C, a reaction pressure of 1 - 5 MPa, a liquid-gas ratio of 2 - 10, and a reaction time of 0.5 - 2 h.

[0025] Preferably, the catalyst can be regenerated and reused during the reaction, and its activity can be restored by calcination.

[0026] The present invention provides a liquefied petroleum gas alkylation reaction catalyst, its preparation method, and its application.

[0027] It has the following beneficial effects:

[0028] 1. By adopting the technical solution of optimizing the molecular sieve pore size and specific surface area, the present invention achieves the technical effect of improving the reaction conversion rate of the catalyst. Compared with the catalysts with smaller pore sizes or lower specific surface areas in the prior art, the present invention solves the problem that reactant molecules are difficult to fully enter the catalyst pores, resulting in low reaction efficiency.

[0029] 2. By reasonably adjusting the metal loading amount, the catalyst has better activity and selectivity, achieving the technical effect of reducing carbon deposition accumulation. Compared with the situation in the prior art where excessive metal loading leads to catalyst blockage and excessive carbon deposition, the present invention effectively avoids these problems and extends the service life of the catalyst.

[0030] 3. By adopting the optimized liquid-gas ratio and reaction time control technology, the present invention achieves the technical effect of effectively reducing the accumulation of carbon deposition on the catalyst. Compared with the catalytic processes with too low liquid-gas ratios or too long reaction times in traditional technologies, the present invention can better avoid the formation of carbon deposition and improve the long-term stability of the catalyst.

[0031] 4. By optimizing the catalyst regeneration ability, the present invention achieves the technical effects of restoring the catalyst performance and long-term stability. Compared with the situation in the prior art where the catalyst is non-renewable or difficult to regenerate after being used for a period of time, the present invention shows excellent activity recovery ability during the catalyst regeneration process, effectively extending the service cycle of the catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a flow chart of the preparation method of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0034] Please refer to the attached Figure 1 , the embodiments of the present invention provide a catalyst for the alkylation reaction of liquefied petroleum gas, which includes the following components by mass percentage:

[0035] ZMQ-1 molecular sieve, the mass ratio of which in the catalyst is 80%-95%;

[0036] The specific surface area of the ZMQ-1 molecular sieve is 300-500 m2 / g, and its mesopore diameter is 2-3 nm.

[0037] The raw materials of the ZMQ-1 molecular sieve include sodium silicate, sodium aluminate, and cetyltrimethylammonium bromide.

[0038] As the main carrier of the catalyst, the ZMQ-1 molecular sieve plays a key role in providing acidic sites and pore structures. Its special pore structure enables the molecular sieve to effectively adsorb reactants and provide a suitable space for the reactant molecules to undergo chemical reactions.

[0039] Function of acidic sites: The ZMQ-1 molecular sieve contains acidic sites, which play a key role in the alkylation reaction. After the light hydrocarbon molecules (such as propane and butane) in liquefied petroleum gas (LPG) enter the pores of the molecular sieve, they react with the acidic sites to generate carbocation intermediates. The intermediates then react with other hydrocarbon molecules to generate larger molecules such as isooctane and other products.

[0040] Advantages of the mesoporous structure: The mesoporous structure (pore diameter of 2-3 nm) of the ZMQ-1 molecular sieve provides enough space to allow larger molecules (such as propane and butane) to enter and react, avoiding the phenomenon of pore blockage, and enhancing the stability and reaction efficiency of the catalyst.

[0041] The raw materials of the ZMQ-1 molecular sieve form a molecular sieve with a specific pore structure during the synthesis process.

[0042] Its specific synthesis mechanism: During the hydrothermal synthesis process, sodium silicate and sodium aluminate provide the silicon source and aluminum source, and cetyltrimethylammonium bromide acts as a template agent, which can form a molecular sieve structure with a specific pore diameter through self-assembly. The presence of the template agent ensures the orderly arrangement of the pores in the molecular sieve, so that it can provide a suitable reaction space for the alkylation reaction of liquefied petroleum gas.

[0043] Under the action of specific hydrothermal conditions: The hydrothermal reaction is carried out at a high temperature of 100-160 °C, and the reaction time is 24-72 h. The high-temperature and high-pressure environment promotes the reaction of the silicon-aluminum source and helps to form the framework structure of the molecular sieve. This structure not only ensures the high specific surface area of the molecular sieve but also ensures its good acid sites and mesopore diameters, effectively improving the activity and stability of the catalyst.

[0044] A transition metal, the mass ratio of which in the catalyst is 0.5%-5%;

[0045] The addition of the transition metal is used to adjust the acid centers of the catalyst, enhance the catalytic activity, and may promote the acceleration of the reaction.

[0046] Among them, the transition metal is at least one of rare earth metals and Group VIII metals.

[0047] The rare earth metal is at least one of cerium and yttrium, the Group VIII metal is at least one of molybdenum and tungsten, and the loading amount of the transition metal is 0.5-5% mass ratio.

[0048] The selection of the transition metal plays a regulatory role in the performance of the catalyst. The influence of its rare earth metals and Group VIII metals on the catalyst is reflected in the following aspects:

[0049] Optimization of acid sites: Rare earth metals and Group VIII metals can change the acid distribution of the molecular sieve and enhance the acid sites on the catalyst surface. The introduction of the transition metal can promote the formation of acid centers and optimize the strength and distribution of acid sites, which is helpful for the activation of reactants and the generation of carbocations.

[0050] Electronic effect and reaction activity: The electronic effect of the transition metal makes the catalyst surface have a stronger electron attraction ability, which helps to improve the activity of the alkylation reaction. For example, molybdenum and tungsten can enhance the affinity of the catalyst for alkylation reaction intermediates and improve its catalytic performance.

[0051] Enhanced stability: Rare earth metals (such as cerium and yttrium) can not only improve the acid sites of the catalyst but also improve the thermal stability and anti-poisoning properties of the catalyst. Especially at high temperatures, the stability of the catalyst is enhanced, and it can withstand high temperatures and the erosion of reactants, extending the service life of the catalyst.

[0052] A binder, the mass ratio of which in the catalyst is 5%-10%;

[0053] The binder mainly plays a role in enhancing the mechanical strength of the catalyst particles and preventing the catalyst particles from breaking during the reaction.

[0054] The binder is bauxite or diatomite.

[0055] The addition of binders such as bauxite or diatomaceous earth is mainly used to improve the physical stability and mechanical strength of the catalyst. In the liquefied petroleum gas alkylation reaction, the catalyst particles need to flow in the reactor and withstand high temperatures and pressures. Therefore, the mechanism of action of the binder is reflected in:

[0056] Improving the mechanical strength of the catalyst: The binder can enhance the structural strength of the catalyst particles, prevent the fragmentation and wear of the catalyst particles during the reaction, and thus maintain the fluidity and stability of the catalyst.

[0057] Reducing the clogging phenomenon of the catalyst: The addition of the binder helps to maintain the particle morphology and pore structure of the catalyst, reduce the pore clogging problem caused by particle fragmentation during the alkylation reaction, and ensure the effective utilization of the catalyst.

[0058] Correspondingly, based on the components of the above catalyst, the present invention provides a preparation method of a liquefied petroleum gas alkylation reaction catalyst, comprising the following steps:

[0059] S1. Synthesize ZMQ-1 molecular sieve. The ZMQ-1 molecular sieve is prepared by hydrothermal synthesis. The hydrothermal synthesis conditions are that the reaction temperature is 100-160 °C, the reaction time is 24-72 h, and the reaction pressure is 0.5-2 MPa;

[0060] The synthesis of ZMQ-1 molecular sieve is the primary step in the catalyst preparation, which determines the acidic sites, pore structure and specific surface area of the catalyst. To achieve efficient catalysis, the synthesis of ZMQ-1 molecular sieve needs to control its crystal structure and pore morphology through hydrothermal synthesis.

[0061] First, sodium silicate and sodium aluminate are used as the silicon source and aluminum source, and they are dissolved in deionized water in the required proportions to form a homogeneous sol. Then, cetyltrimethylammonium bromide (CTAB) is added as a template agent. CTAB self-assembles to form an ordered nanoporous structure under hydrothermal conditions, which provides an ideal pore and pore size for the molecular sieve. Then, the entire sol undergoes hydrothermal synthesis in a closed reaction kettle. The reaction temperature is set at 100-160 °C, the reaction pressure is 0.5-2 MPa, and the reaction time is 24-72 h. During this process, sodium silicate and sodium aluminate undergo hydrolysis reactions in a high-temperature and high-pressure environment to form a silicon-aluminate framework. The template agent guides the pore structure of the molecular sieve through physicochemical interactions.

[0062] During the hydrothermal synthesis process, the control of temperature and time is crucial. When the temperature is too low, the reaction is incomplete and it is difficult to obtain an ideal framework structure; when the temperature is too high or the reaction time is too long, it may lead to the instability of the framework structure and affect the performance of the catalyst. Therefore, by reasonably adjusting the hydrothermal reaction conditions, while ensuring a high specific surface area, the pore diameter can be maintained within the range of 2 - 3 nm, thus providing a suitable reaction space for the alkylation reaction.

[0063] The synthesized ZMQ-1 molecular sieve is cooled to room temperature and washed with deionized water to remove unreacted substances and template agents. The washed molecular sieve is dried at 100 - 120 °C to remove moisture, preparing for subsequent metal loading.

[0064] The high temperature and high pressure in the hydrothermal reaction help to fully dissolve and reorganize the aluminosilicate substances to form an ordered molecular sieve structure. The ordered pore structure formed by self-assembly of CTAB as a template agent enables the synthesized ZMQ-1 molecular sieve to have suitable acidic sites and pore structures, providing an appropriate reaction space and effectively enhancing the catalytic performance of the catalyst.

[0065] S2. Immerse the ZMQ-1 molecular sieve in a solution containing rare earth metals and Group VIII metal salts;

[0066] After synthesis and drying, the ZMQ-1 molecular sieve has certain acidic sites and pore structures. The next step is to load transition metals onto the surface of the molecular sieve to optimize its acidic sites and improve catalytic activity.

[0067] In this step, we immerse the ZMQ-1 molecular sieve in a solution containing rare earth metals (such as cerium, yttrium) and Group VIII metals (such as molybdenum, tungsten) salts. Common metal salts include cerium chloride (CeCl3), yttrium chloride (YCl3), and ammonium molybdate ((NH4)6Mo7O 24 ) etc. These metal salts are dissolved in water to form a metal ion solution. The ZMQ-1 molecular sieve is placed in this solution for impregnation. Usually, the impregnation time is 2 - 12 h and the temperature is controlled at 25 - 50 °C. During this process, metal ions enter the pore channels or surface acidic sites of the ZMQ-1 molecular sieve through electrostatic adsorption or ion exchange.

[0068] Ions of rare earth metals and Group VIII metals have strong acidity and can interact with the acidic sites in the ZMQ-1 molecular sieve through ion exchange, enhancing the acidity and electronic properties of the catalyst, thereby improving the catalytic activity of the catalyst. The loading of metals can form strong acidic sites on the surface of the molecular sieve, improving the reactivity of the catalyst. In addition, the electronic effect of transition metals helps to improve the stability of catalytic reaction intermediates and promote the alkylation reaction.

[0069] S3. Dry the impregnated ZMQ-1 molecular sieve at a drying temperature of 100-120 °C for 8-12 h;

[0070] The impregnated ZMQ-1 molecular sieve needs to remove the excess solvent through drying to stably load metal ions on the surface of the molecular sieve. During the drying process, the temperature is set at 100-120 °C and the drying time is 8-12 h.

[0071] The main purpose of the drying step is to remove the solvent and form stable oxides of metal ions on the surface of the molecular sieve. Through heating, the moisture in the solvent and the dissolved chemical reagents are volatilized, ensuring that the metal ions are firmly bound to the acidic sites of the ZMQ-1 molecular sieve, providing preparation for the subsequent calcination step.

[0072] S4. Calcinate the dried catalyst at a calcination temperature of 450-600 °C for 4-6 h;

[0073] In the dried catalyst, the metal salt is still in an unstable state. Therefore, it is necessary to convert the metal salt into metal oxide through the calcination process to enhance its stability and catalytic performance. The calcination temperature is set at 450-600 °C, the calcination time is 4-6 h, and the calcination atmosphere is air.

[0074] The calcination process is an important step in metal loading. During this process, the metal salt decomposes and oxidizes to convert into metal oxides (such as CeO2, MoO3). These metal oxides are stably loaded on the acidic sites of the ZMQ-1 molecular sieve, enhancing the thermal stability and reaction activity of the catalyst. Precise control of the calcination temperature and time can ensure the uniform distribution of metal oxides on the surface of the molecular sieve, while avoiding over-oxidation or damage to the catalyst framework.

[0075] S5. Mix the calcined catalyst with a binder and carry out wet granulation to obtain catalyst particles with a particle size of 1-5 mm;

[0076] The calcined catalyst usually needs to be granulated by wet granulation to improve its physical strength and enhance the fluidity of the catalyst during the reaction process. In the wet granulation step, the calcined catalyst is mixed with a binder (such as bauxite or diatomite) in a certain proportion and subjected to wet granulation to obtain catalyst particles with a particle size of 1-5 mm.

[0077] The role of the binder is to enhance the structural strength of the catalyst particles and prevent the particles from breaking during the reaction process. Wet granulation forms aggregates with good mechanical strength of the catalyst particles through wetting and mechanical extrusion. By reasonably controlling the ratio of the binder to the catalyst, the fluidity and strength of the particles can be ensured to maintain a stable catalytic effect in the reactor.

[0078] S6. Dry and screen the catalyst particles to obtain the final catalyst.

[0079] Finally, the catalyst particles after wet granulation need to be dried to remove excess moisture and screened to obtain the catalyst with the desired particle size range (1 - 5 mm).

[0080] The drying step removes the residual moisture and solvents in the wet granulation process, ensuring that the catalyst particles can maintain good structure and stability during high-temperature reactions. The screening step helps to remove particles that do not meet the specifications and ensures the uniformity and stability of the final catalyst particles.

[0081] Correspondingly, the present invention also provides an application method of a liquefied petroleum gas alkylation reaction catalyst. The catalyst is used in the liquefied petroleum gas alkylation reaction, with a reaction temperature of 200 - 400 °C, a reaction pressure of 1 - 5 MPa, a liquid-gas ratio of 2 - 10, and a reaction time of 0.5 - 2 h.

[0082] The catalyst can be regenerated and reused during the reaction process, and its activity can be restored by calcination.

[0083] In this embodiment, the essence of the liquefied petroleum gas alkylation reaction is to promote the reaction of light hydrocarbons (such as propane and butane) with olefins (such as isobutene) through the catalyst to produce higher-value alkylation products. To make this reaction proceed smoothly, the role of the catalyst is crucial. Specifically, the catalyst provides acidic sites during the reaction process, and these acidic sites can effectively activate the reactant molecules, especially by forming carbocation intermediates with light hydrocarbon molecules, thereby promoting the reaction. Due to the specific pore structure and high specific surface area of ZMQ-1 zeolite, it provides an ideal reaction space for the alkylation reaction, enabling the reactants to fully contact the catalyst surface and increasing the reaction opportunities and efficiency.

[0084] In the specific reaction operation, the performance of the catalyst is also significantly affected by the reaction conditions. To optimize the catalytic effect, the reaction temperature is usually set between 200 - 400 °C. This temperature range can ensure that the reactants can be converted with sufficient thermal energy support, but it will not cause excessive decline of the catalyst or the generation of side reactions. Too low a temperature will result in too slow a reaction rate and insufficient activation of the reactants, while too high a temperature may accelerate the deactivation of the catalyst. Similarly, the reaction pressure is controlled between 1 - 5 MPa. The increase in pressure can increase the density of the reactants, thereby promoting the reaction rate, but too high a pressure may damage the structural stability of the catalyst. Therefore, the precise control of the reaction temperature and pressure can improve the reaction conversion rate while ensuring the stability of the catalyst.

[0085] The liquid-gas ratio and reaction time also directly affect the reaction efficiency. The liquid-gas ratio is set between 2 and 10. An appropriate liquid-gas ratio can ensure the optimal loading of the catalyst, avoiding catalyst clogging caused by excessive reactant concentration and ensuring sufficient reactant supply. The reaction time is set to 0.5 - 2 h, which can ensure the complete conversion of reactants and avoid thermal decay or performance degradation of the catalyst under too long reaction time.

[0086] During the use of the catalyst, its activity and efficiency gradually decrease with the progress of the reaction. To solve this problem, the catalyst in the present invention has good regeneration ability and can restore its activity through the calcination process. The calcination step heats the catalyst to 450 - 600 °C at high temperature to effectively remove the deposits and inactive substances accumulated during the reaction. This process not only cleans the surface of the catalyst but also promotes the transformation of metal oxides from salt form to more stable oxides, further enhancing the stability and activity of the catalyst. After calcination, the catalyst can restore its initial catalytic performance and extend its service life. Therefore, it has strong regeneration ability and can be repeatedly used in multiple reaction cycles, avoiding the high cost of frequent catalyst replacement.

[0087] Generally speaking, the application method of the liquefied petroleum gas alkylation reaction catalyst enables the activity of the catalyst to be maintained and restored during use by finely regulating the reaction conditions and catalyst performance. This optimized operation method not only improves the conversion rate and selectivity of the reaction but also reduces the replacement frequency of the catalyst through the regeneration mechanism, realizing the long-term and efficient use of the catalyst and further improving the economy and sustainability of the reaction.

[0088] To better understand the present invention, the above method will be described in detail below in combination with specific embodiments.

[0089] Example 1:

[0090] Implementation steps:

[0091] Synthesize ZMQ-1 molecular sieve: Dissolve sodium silicate (30%), sodium aluminate (15%) and cetyltrimethylammonium bromide (CTAB, 1%) in deionized water to form a homogeneous sol. This sol undergoes hydrothermal reaction at 120 °C for 48 h, and the reaction pressure is maintained at 1 MPa. After cooling, the ZMQ-1 molecular sieve is separated, washed and dried at 110 °C for 12 h.

[0092] Metal impregnation: Take solutions of cerium chloride (1 mol / L, 2%) and ammonium molybdate (0.5 mol / L, 2%), immerse the synthesized ZMQ-1 molecular sieve in them at a temperature of 30 °C for 10 h. After impregnation, the molecular sieve is taken out and dried.

[0093] Calcination: Put the dried catalyst into a tubular furnace and calcine it in air at 500 °C for 5 h.

[0094] Granulation and screening: Mix the calcined catalyst with diatomaceous earth (5%) and perform wet granulation to obtain catalyst particles with a particle size of 2 - 3 mm. Dry and screen the particles to finally obtain a catalyst with uniform size.

[0095] Process parameters: Reaction temperature 350 °C; reaction pressure 2 MPa; liquid-gas ratio 4; reaction time 1 h.

[0096] Example 2:

[0097] Implementation steps:

[0098] Synthesize ZMQ-1 molecular sieve: Prepare a solution of sodium silicate (28%), sodium aluminate (12%) and CTAB (0.8%) and carry out a hydrothermal reaction. The reaction conditions are set at 100 °C, the reaction time is 72 h, and the reaction pressure is 1.5 MPa. After cooling, separate and wash the ZMQ-1 molecular sieve, and set the drying temperature at 115 °C and the drying time at 10 h.

[0099] Metal impregnation: Use cerium chloride (1.5 mol / L) and ammonium tungstate (0.8 mol / L) solutions to impregnate the molecular sieve. The temperature is 35 °C, the impregnation time is 8 h, and then drying treatment is carried out.

[0100] Calcination: Put the dried catalyst into a high-temperature furnace and calcine it at 550 °C for 4 h to ensure that the metal oxide is completely deposited on the molecular sieve.

[0101] Wet granulation and screening: Mix the calcined catalyst with bauxite (6%) and form particles by wet granulation. The particle size range is 2 - 4 mm. Finally, carry out screening and drying treatment.

[0102] Process parameters: Reaction temperature 300 °C; reaction pressure 3 MPa; liquid-gas ratio 6; reaction time 1.5 h.

[0103] Example 3:

[0104] Implementation steps:

[0105] Synthesize ZMQ-1 molecular sieve: Mix sodium silicate (32%), sodium aluminate (14%) and CTAB (1%) in proportion and react under hydrothermal conditions at 130 °C for 60 h, with a reaction pressure of 1.2 MPa. After the reaction, cool, wash, and dry at 120 °C for 12 h.

[0106] Metal impregnation: The ZMQ-1 molecular sieve was impregnated with yttrium chloride (0.8 mol / L) and ammonium molybdate (0.4 mol / L) solutions. The impregnation temperature was set at 40 °C and the impregnation time was 6 h, followed by drying.

[0107] Calcination: The dried catalyst was calcined at a temperature of 480 °C for 5 h to completely load the metal oxide on the molecular sieve.

[0108] Wet granulation and screening: The calcined catalyst was mixed with diatomite (8%) and formed into granules by wet granulation. The particle size was 3 - 5 mm. Screening and drying gave the final catalyst.

[0109] Process parameters: Reaction temperature 320 °C; Reaction pressure 4 MPa; Liquid-gas ratio 5; Reaction time 1 h.

[0110] Example 4:

[0111] Implementation steps:

[0112] Synthesis of ZMQ-1 molecular sieve: Sodium silicate (30%), sodium aluminate (13%) and CTAB (0.9%) were dissolved in water, reacted at 110 °C for 48 h under a reaction pressure of 1.3 MPa. After the reaction, it was cooled, washed and dried at 115 °C.

[0113] Metal impregnation: The ZMQ-1 molecular sieve was impregnated with cerium chloride (0.7 mol / L) and ammonium molybdate (0.5 mol / L) solutions at a temperature of 30 °C for 8 h, followed by drying.

[0114] Calcination: The dried catalyst was calcined at 520 °C for 4 h to promote the stabilization of the metal.

[0115] Wet granulation and screening: The catalyst was mixed with bauxite (7%) and formed into granules by wet granulation. The particle size was 2 - 4 mm. Screening and drying gave the final catalyst.

[0116] Process parameters: Reaction temperature 310 °C; Reaction pressure 2.5 MPa; Liquid-gas ratio 7; Reaction time 1 h.

[0117] Comparative Example 1: Traditional low specific surface area molecular sieve catalyst

[0118] Preparation steps of the comparative example:

[0119] Synthesis of molecular sieve: Sodium silicate (30%) and sodium aluminate (12%) were used as raw materials to prepare an aqueous solution, and CTAB (1%) was added as a template agent, and hydrothermal reaction was carried out at a temperature of 100 °C. The reaction time was 48 h and the reaction pressure was 1 MPa. Under these conditions, the specific surface area of the molecular sieve was about 200 m 2 / g, with a relatively small pore size range, which cannot effectively provide sufficient reaction space.

[0120] Metal impregnation: The synthesized molecular sieve was impregnated with a solution of yttrium chloride (0.5 mol / L) and ammonium molybdate (0.3 mol / L). The impregnation time was set to 6 h, and the temperature was controlled at 30 °C to load the metal on the surface of the molecular sieve.

[0121] Calcination: The impregnated catalyst was calcined at a temperature of 480 °C for 4 h to ensure complete metal loading and enhance the stability of the catalyst.

[0122] Wet granulation and screening: The calcined catalyst was mixed with diatomaceous earth (10%) and formed into catalyst particles of 3 - 5 mm by wet granulation, followed by screening and drying.

[0123] Comparative Example 2: Catalyst with high specific surface area but low pore volume

[0124] Preparation steps of the comparative example:

[0125] Synthesis of molecular sieve: A solution was prepared using sodium silicate (35%) and sodium aluminate (15%), and CTAB (1.5%) was added as a template agent. Hydrothermal reaction was carried out at 120 °C. The reaction time was 72 h and the pressure was 1.2 MPa. The ZMQ-1 molecular sieve obtained under these conditions had a relatively high specific surface area (450 m 2 / g), but a relatively small pore size (1.8 - 2.0 nm).

[0126] Metal impregnation: Metal impregnation was carried out using a solution of cerium chloride (1.0 mol / L) and ammonium tungstate (0.6 mol / L). The impregnation temperature was set to 25 °C and the impregnation time was 8 h. The impregnated catalyst was dried at 115 °C.

[0127] Calcination: The impregnated catalyst was calcined in air at 500 °C for 5 h to ensure complete loading of metal oxides on the surface of the molecular sieve.

[0128] Wet granulation and screening: The calcined catalyst was mixed with bauxite (8%) and formed into particles by wet granulation. The particle size was 2 - 4 mm, and finally the final catalyst was obtained through screening and drying.

[0129] Comparative Example 3: Catalyst with excessive metal loading

[0130] Preparation steps of the comparative example:

[0131] Synthesis of molecular sieve: Using sodium silicate (30%) and sodium aluminate (13%) as raw materials, after adding CTAB (1.0%) and dissolving, hydrothermal reaction was carried out at 130 °C for 72 h, and the reaction pressure was 1.5 MPa. The specific surface area of the obtained molecular sieve was 400 m2 / g, with a pore size of 2.1 nm.

[0132] Metal impregnation: The ZMQ-1 molecular sieve was impregnated with a cerium chloride (2.0 mol / L) and ammonium molybdate (1.5 mol / L) solution. The impregnation time was 10 h and the temperature was set at 40 °C. The amount of metal loaded in this step was relatively large, reaching 8%.

[0133] Calcination: The impregnated catalyst was calcined at 600 °C for 5 h to ensure the stable deposition of the excessive metal and remove the redundant metal through the calcination process.

[0134] Wet granulation and screening: The calcined catalyst was mixed with bauxite (5%) and subjected to wet granulation to obtain catalyst particles with a size of 1 - 3 mm, followed by drying and screening.

[0135] Comparative Example 4: Application of the catalyst without optimizing the liquid-gas ratio and reaction time

[0136] Preparation steps of the comparative example:

[0137] Synthesis of molecular sieve: Hydrothermal reaction was carried out using sodium silicate (33%) and sodium aluminate (12%). The template agent CTAB was 1.2%. The hydrothermal synthesis conditions were 120 °C, reaction time of 72 h, and reaction pressure of 1.5 MPa. The obtained ZMQ-1 molecular sieve had a pore size of 2.2 nm and a specific surface area of 380 m 2 / g.

[0138] Metal impregnation: Metal loading was carried out using a cerium chloride (1.0 mol / L) and ammonium molybdate (0.6 mol / L) solution at a temperature of 35 °C for 8 h. Subsequently, it was dried.

[0139] Calcination: The impregnated catalyst was calcined at 500 °C for 4 h.

[0140] Wet granulation and screening: The calcined catalyst was mixed with diatomaceous earth (6%) and formed by wet granulation. The particle size was 2 - 4 mm, and then it was screened and dried to obtain the final catalyst.

[0141] Application process: The reaction temperature was 280 °C; the reaction pressure was 1.5 MPa; the liquid-gas ratio was set at 1; the reaction time was 4 h.

[0142] Experiment 1: Study on the influence of specific surface area and pore size on the reaction performance of the catalyst

[0143] Purpose of the experiment: This experiment aims to compare the effects of specific surface area and pore size on the reaction performance of the catalyst in the liquefied petroleum gas alkylation reaction. By comparing the catalysts of Example 1 and Comparative Example 1, explore how the differences in specific surface area and pore size affect the conversion rate, selectivity, carbon deposition amount of the reaction, and the stability of the catalyst.

[0144] Experimental procedure:

[0145] Catalyst preparation:

[0146] Example 1: Synthesize the ZMQ-1 molecular sieve catalyst, with the raw materials being sodium silicate, sodium aluminate, and CTAB (1%). The hydrothermal synthesis conditions are 120 °C, reaction time 48 h, reaction pressure 1 MPa, to obtain a catalyst with a specific surface area of 350 m

[0147] / g and a pore size range of 2 - 3 nm.

[0148] Comparative Example 1: Synthesize the ZMQ-1 molecular sieve catalyst, with the raw materials being sodium silicate, sodium aluminate, and CTAB (1%). The hydrothermal synthesis conditions are 120 °C, reaction time 48 h, reaction pressure 1 MPa, to obtain a catalyst with a specific surface area of 200 m 2 / g and a pore size range of 1.8 - 2.0 nm.

[0149] Catalyst pretreatment: Calcinate the catalysts of Example 1 and Comparative Example 1 in air at 500 °C for 4 h to stabilize the active sites of the catalyst.

[0150] Reaction device: Use a fixed-bed reactor for the liquefied petroleum gas alkylation reaction. Load an equal mass of catalyst particles each time, with the particle size being 2 - 3 mm.

[0151] Reaction conditions: Temperature 350 °C; pressure 2 MPa; liquid-gas ratio 4; reaction time 1 h.

[0152] Testing method:

[0153] Use gas chromatography to analyze the composition of the product and determine the conversion rate and selectivity of the alkylation product.

[0154] Measure the carbon deposition amount of the catalyst, and use thermogravimetric analysis (TGA) to determine the carbon deposition amount.

[0155] Experimental data recording: After the experiment, record the conversion rate, selectivity of the alkylation product, and carbon deposition amount of the catalyst for each group of experiments.

[0156] Table 1: Data table of the effects of specific surface area and pore size on the reaction performance of the catalyst Name of the data table: Data of the effects of specific surface area and pore size on the reaction performance of the catalyst

[0157]

[0158]

[0159] Summary: The mechanism of the catalytic reaction indicates that the specific surface area and pore size of the catalyst directly affect the diffusion and reaction process of reactant molecules on the catalyst surface. In Example 1, the catalyst with a relatively high specific surface area (350 m 2 / g) and moderate pore size can provide more reactive sites, promote the diffusion of reactants, and improve the conversion rate and selectivity of the reaction. A higher specific surface area means a more extensive surface area, which can provide more reaction sites, directly promoting the alkylation reaction. The optimization of the pore size (2 - 3 nm) allows reactant molecules to more easily enter the pores and participate in the reaction, enhancing the overall efficiency of the reaction.

[0160] On the contrary, in the catalyst of Comparative Example 1, the relatively low specific surface area (200 m 2 / g) and smaller pore size (1.8 - 2.0 nm) limit the entry of reactants and the progress of the catalytic reaction. This not only reduces the conversion rate of the catalyst but also affects the selectivity of the alkylation product. The smaller pore size increases the residence time of reactants and products in the pores, prone to accumulation, resulting in an increase in carbon deposition. In the experimental data, the carbon deposition amount in Example 1 is significantly lower than that in Comparative Example 1, indicating that a larger specific surface area and moderate pore size help slow down carbon deposition accumulation and extend the service life of the catalyst.

[0161] The relationship between the reaction performance of the catalyst and the carbon deposition amount further reveals the role of the pore structure of the catalyst. A larger specific surface area and optimized pore size enable the catalyst to more effectively process reactants and reduce carbon deposition accumulation, thus maintaining a higher reaction stability. This phenomenon is particularly evident in the experimental data, where the catalyst in Example 1 shows a higher conversion rate and a lower carbon deposition amount than the catalyst in Comparative Example 1 during the reaction.

[0162] From these data and mechanism analyses, it can be concluded that the optimization of the specific surface area and pore size of the catalyst not only improves the efficiency of the catalytic reaction but also reduces the carbon deposition amount of the catalyst and maintains the long-term stability of the catalyst. These results provide important theoretical support for the further optimization of the catalyst, especially in the application of high-efficiency liquefied petroleum gas alkylation reaction.

[0163] Experiment 2: Study on the Influence of Metal Loading Amount on the Reaction Performance of ZMQ-1 Molecular Sieve Catalyst

[0164] Purpose of the experiment: This experiment aims to study the influence of metal loading on the activity and stability of the ZMQ-1 molecular sieve catalyst in the liquefied petroleum gas alkylation reaction. By comparing the catalysts of Example 2 and Comparative Example 2, explore how the change in metal loading affects the reaction conversion rate, selectivity, carbon deposition amount of the catalyst, and the regeneration ability of the catalyst.

[0165] Experimental procedures:

[0166] Catalyst preparation:

[0167] Example 2: Synthesize the ZMQ-1 molecular sieve catalyst, with the raw materials being sodium silicate, sodium aluminate, and CTAB (0.8%). The hydrothermal reaction conditions are 100 °C, reaction time 72 h, reaction pressure 1.2 MPa, obtaining a molecular sieve with a specific surface area of 450 m 2 / g and a pore size of 1.8 - 2.0 nm.

[0168] Comparative Example 2: Synthesize the ZMQ-1 molecular sieve catalyst, with the raw materials being sodium silicate, sodium aluminate, and CTAB (1.5%). The hydrothermal reaction conditions are 100 °C, reaction time 72 h, reaction pressure 1.2 MPa, obtaining a molecular sieve with a specific surface area of 450 m 2 / g and a pore size of 1.8 - 2.0 nm.

[0169] Metal loading:

[0170] Example 2: Immerse the molecular sieve with cerium chloride (1.0 mol / L) and ammonium tungstate (0.6 mol / L) solutions, with a metal loading of 2%, impregnation time 8 h, and then conduct drying.

[0171] Comparative Example 2: Immerse the molecular sieve with cerium chloride (2.0 mol / L) and ammonium molybdate (1.5 mol / L) solutions, with a metal loading of 8%, impregnation time 8 h, and then conduct drying.

[0172] Calcination: Calcinate the impregnated catalyst in air at 500 °C for 5 h to ensure stable metal loading.

[0173] Reaction conditions:

[0174] Reactor: Use a fixed-bed reactor for the liquefied petroleum gas alkylation reaction. Use the same mass of catalyst particles in each experiment, with the particle size being 2 - 3 mm.

[0175] Reaction parameters: Temperature 320 °C; pressure 3 MPa; liquid-gas ratio 6; reaction time 1.5 h.

[0176] Testing methods:

[0177] Use gas chromatography to analyze the product composition and calculate the reaction conversion rate and the selectivity of alkylation products.

[0178] The carbon deposition amount of the catalyst was determined by thermogravimetric analysis (TGA) to evaluate the carbon deposition accumulation and activity change of the catalyst.

[0179] Data recording: Record the conversion rate, alkylation product selectivity and catalyst carbon deposition amount of each experiment.

[0180] Table 2: Data on the effect of metal loading on the reaction performance of the catalyst

[0181]

[0182] Summary: The change in the metal loading in the catalyst directly affects its reaction activity. The catalyst in Example 2 has a low metal loading (2%), showing a high reaction conversion rate (93.5%) and an alkylation product selectivity of 69.8%. The low metal loading keeps a high density of active sites on the catalyst surface, promoting the efficient progress of the reaction. In contrast, the metal loading of the catalyst in Comparative Example 2 is 8%, resulting in an excessive number of active sites on the catalyst surface, which instead produces an excessive metal aggregation phenomenon, reducing the reaction activity, and the conversion rate is only 87.6%. In addition, the excessive metal loading also leads to an increase in the carbon deposition amount of the catalyst, and the carbon deposition amount in Comparative Example 2 (5.2 mg / g) is significantly higher than that in Example 2 (3.0 mg / g).

[0183] Mechanistically, the catalyst with a low metal loading can maintain a better distribution of acidic sites and avoid the aggregation of excessive metal species, which helps to improve the activity and selectivity of the catalytic reaction. On the contrary, when the metal loading is too high, excessive metal species will form deposits or cluster structures, which not only reduces the catalytic activity but also may cause pore blockage, further affecting the reaction efficiency of the catalyst. In addition, the higher metal loading increases the carbon deposition tendency of the catalyst, which may lead to a gradual decrease in the catalyst activity. The data show that a low metal loading optimizes the activity and stability of the catalyst.

[0184] By controlling the metal loading, carbon deposition accumulation can be reduced while maintaining high activity, enabling the catalyst to exhibit good stability during long-term reactions. These results further verify the relationship between the metal loading and the reaction performance of the catalyst, emphasizing the precise control of the metal loading in catalyst design.

[0185] Experiment 3: Influence of the catalyst regeneration ability on its long-term performance

[0186] Experiment purpose: This experiment aims to study the influence of the catalyst regeneration ability on its long-term performance in the liquefied petroleum gas alkylation reaction. By comparing the catalysts of Example 3 and Comparative Example 3, the stability and carbon deposition removal effect of the catalyst after multiple reactions are explored, and the influence of the regeneration process on the recovery of the catalyst performance is verified.

[0187] Experimental procedures:

[0188] Catalyst preparation:

[0189] Example 3: Synthesize the ZMQ-1 molecular sieve catalyst with sodium silicate, sodium aluminate, and CTAB (1%) as raw materials. The hydrothermal synthesis conditions are 130 °C, reaction time of 72 h, and reaction pressure of 1.5 MPa, obtaining a molecular sieve with a specific surface area of 400 m 2 / g and a pore diameter of 2.1 nm.

[0190] Comparative Example 3: Synthesize the ZMQ-1 molecular sieve catalyst with sodium silicate, sodium aluminate, and CTAB (1%) as raw materials. The hydrothermal synthesis conditions are 130 °C, reaction time of 72 h, and reaction pressure of 1.5 MPa, obtaining a molecular sieve with a specific surface area of 400 m 2 / g and a pore diameter of 2.1 nm.

[0191] Metal loading:

[0192] Example 3: Immerse the molecular sieve with cerium chloride (0.7 mol / L) and ammonium molybdate (0.5 mol / L) solutions, with a metal loading of 5%, impregnation time of 6 h, and calcination treatment after drying.

[0193] Comparative Example 3: Immerse the molecular sieve with cerium chloride (2.0 mol / L) and ammonium molybdate (1.0 mol / L) solutions, with a metal loading of 10%, impregnation time of 6 h, and calcination treatment after drying.

[0194] Reaction process:

[0195] Use a fixed-bed reactor for the alkylation reaction of liquefied petroleum gas. The size of the catalyst particles is 2 - 3 mm, and the same mass of catalyst is loaded for each reaction.

[0196] Reaction conditions: temperature 300 °C; pressure 4 MPa; liquid-gas ratio 5; reaction time 1 h.

[0197] Catalyst regeneration process: After every 5 reactions, the catalyst is calcined at a temperature of 500 °C for 4 h to remove carbon deposition and restore the activity of the catalyst.

[0198] Testing method:

[0199] After each reaction, analyze the conversion rate of the product and the selectivity of the alkylation product by gas chromatography.

[0200] Use thermogravimetric analysis (TGA) to determine the carbon deposition amount of the catalyst and record the change in activity before and after the regeneration process.

[0201] Data record: Record the conversion rate, selectivity, and catalyst carbon deposition amount after each reaction. Pay special attention to the influence of the catalyst regeneration effect on the catalyst performance.

[0202] Table 3: Data on the influence of catalyst regeneration ability on catalytic performance

[0203]

[0204]

[0205] Summary: The regeneration ability of the catalyst is directly related to its stability and activity recovery ability in long-term reactions. The catalyst in Example 3 showed good stability and a low carbon deposition amount (3.2 mg / g) after 5 reaction and regeneration treatments, and the conversion rate remained at about 91.4%. In contrast, due to the excessive metal loading (10%) of the catalyst in Comparative Example 3, the carbon deposition amount increased significantly (5.5 mg / g) after the reaction, and the conversion rate was low, only 78.6%. This phenomenon indicates that excessive metal loading on the catalyst not only easily leads to the aggregation of metals on the catalyst surface but also may accelerate the formation of carbon deposition, thus affecting the efficiency of the catalytic reaction.

[0206] From a mechanistic perspective, the carbon deposition on the catalyst is mainly due to the incomplete conversion of reactants or their excessive accumulation in the catalyst pores. In this process, the aggregation of metal species and the blockage of pores play important roles. A low metal loading amount helps to keep the active site distribution of the catalyst uniform and reduce the accumulation of carbon deposition, while a high metal loading may lead to the overcrowding of active sites, thus accelerating the formation of carbon deposition. Experimental data show that the catalyst in Example 3 can still maintain a high reaction activity and selectivity after multiple regenerations, which verifies that the regeneration process can effectively restore the performance of the catalyst.

[0207] Experiment 4: Influence of liquid-gas ratio and reaction time on the reaction performance of the catalyst

[0208] Experimental purpose: This experiment aims to study the influence of the liquid-gas ratio and reaction time on the reaction performance of the catalyst in the liquefied petroleum gas alkylation reaction. By comparing the catalysts in Example 4 and Comparative Example 4, explore the changes in the conversion rate, selectivity, and stability of the catalyst under different liquid-gas ratios and reaction times, and reveal the influence mechanism on the catalyst performance.

[0209] Experimental procedure:

[0210] Catalyst preparation:

[0211] Example 4: Synthesize the ZMQ-1 molecular sieve catalyst, with raw materials being sodium silicate, sodium aluminate, and CTAB (1.0%). The hydrothermal synthesis conditions are 120 °C, reaction time 72 hours, and reaction pressure 1.5 MPa, obtaining a specific surface area of 380 m2 Molecular sieve with a pore size of 2.2 nm and a mass of / g.

[0212] Comparative Example 4: Synthesis of ZMQ-1 molecular sieve catalyst, with raw materials being sodium silicate, sodium aluminate, and CTAB (1.0%). The hydrothermal synthesis conditions were 120 °C, reaction time of 72 hours, and reaction pressure of 1.5 MPa, obtaining a molecular sieve with a specific surface area of 380 m 2 / g and a pore size of 2.2 nm.

[0213] Metal loading:

[0214] Example 4: The molecular sieve was impregnated with cerium chloride (1.0 mol / L) and ammonium molybdate (0.5 mol / L) solutions, with a metal loading of 5%, impregnation time of 6 hours, and then dried.

[0215] Comparative Example 4: The molecular sieve was impregnated with cerium chloride (1.5 mol / L) and ammonium molybdate (1.0 mol / L) solutions, with a metal loading of 8%, impregnation time of 6 hours, and then dried.

[0216] Reaction conditions:

[0217] Example 4: The liquid-gas ratio was 7, the reaction time was 1 hour, the temperature was set at 310 °C, and the reaction pressure was 2.5 MPa.

[0218] Comparative Example 4: The liquid-gas ratio was 1, the reaction time was 4 hours, the temperature was set at 310 °C, and the reaction pressure was 2.5 MPa.

[0219] Reaction apparatus: A fixed-bed reactor was used, and the same mass of catalyst particles with a particle size of 2 - 3 mm was loaded for each experiment.

[0220] Testing method:

[0221] Gas chromatography analysis: Determine the conversion rate of the alkylation reaction, product selectivity, and the carbon deposition amount of the catalyst.

[0222] Thermogravimetric analysis (TGA): Determine the carbon deposition amount of the catalyst and evaluate the stability of the catalyst.

[0223] Data recording: Record the conversion rate, product selectivity, and carbon deposition amount of each reaction, and analyze the effects of the liquid-gas ratio and reaction time on the catalyst performance.

[0224] Table 4: Data on the effects of the liquid-gas ratio and reaction time on the reaction performance of the catalyst

[0225]

[0226]

[0227] Summary: The changes in the liquid-gas ratio and reaction time significantly affect the reaction efficiency and stability of the catalyst. In the experiment, the catalyst in Example 4 showed a high conversion rate (92.1%) and a low carbon deposition amount (3.0 mg / g) under the conditions of a liquid-gas ratio of 7 and a reaction time of 1 hour. In contrast, in Comparative Example 4, under the conditions of a liquid-gas ratio of 1 and a reaction time of 4 hours, the catalyst showed a low conversion rate (75.4%) and a high carbon deposition amount (6.2 mg / g). These results indicate that an appropriate liquid-gas ratio and a short reaction time help to improve the reaction activity and selectivity of the catalyst while reducing carbon deposition accumulation.

[0228] From a mechanistic perspective, the influence of the liquid-gas ratio and reaction time on the catalytic reaction is mainly reflected in the contact time and concentration of the reactants with the active sites on the catalyst surface. When the liquid-gas ratio is high, the concentration of the reactants in the reactor is low, which is conducive to the full utilization of the active sites on the catalyst surface, avoiding the excessive accumulation of reactants and the blockage of the catalyst pores, thereby reducing the formation of carbon deposition. A short reaction time, on the other hand, helps to avoid overreaction, reduce the formation of by-products, and further improve the selectivity of the products.

[0229] Relatively speaking, a low liquid-gas ratio and an overly long reaction time will lead to the accumulation of reactants on the catalyst surface, increasing the risk of carbon deposition accumulation and catalyst deactivation. The increase in carbon deposition will not only reduce the reaction efficiency of the catalyst but may also lead to a decrease in the long-term stability of the catalyst. These phenomena were verified in Comparative Example 4, where the significant increase in the carbon deposition amount directly affected the conversion rate and selectivity of the catalyst.

[0230] The optimization of the liquid-gas ratio and reaction time can not only improve the efficiency of the catalytic reaction, reduce the formation of carbon deposition, but also improve the long-term stability and regeneration ability of the catalyst. By controlling these factors, the activity of the catalyst can be maintained during long-term reactions, thereby extending its service life.

[0231] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A catalyst for the alkylation reaction of liquefied petroleum gas, characterized in that, By mass percentage, it includes the following components: ZMQ-1 molecular sieve, with a mass fraction in the catalyst of 80%-95%; Transition metal, with a mass fraction in the catalyst of 0.5%-5%; Binder, with a mass fraction in the catalyst of 5%-10%; Among them, the transition metal is at least one of rare earth metals and Group VIII metals.

2. The liquefied petroleum gas alkylation reaction catalyst according to claim 1, wherein The specific surface area of the ZMQ-1 molecular sieve is 300-500 m 2 / g, and its mesopore diameter is 2-3 nm.

3. A liquefied petroleum gas alkylation reaction catalyst according to claim 1, wherein The rare earth metal is at least one of cerium and yttrium, the Group VIII metal is at least one of molybdenum and tungsten, and the loading amount of the transition metal is 0.5-5% mass ratio.

4. A liquefied petroleum gas alkylation reaction catalyst according to claim 1, wherein, The raw material of the ZMQ-1 molecular sieve includes sodium silicate, sodium aluminate and cetyltrimethylammonium bromide.

5. The liquefied petroleum gas alkylation reaction catalyst according to claim 1, wherein The binder is bauxite or diatomite.

6. A preparation method of a liquefied petroleum gas alkylation reaction catalyst according to any one of claims 1-5, characterized in that, It includes the following steps: S1. Synthesize ZMQ-1 molecular sieve. The ZMQ-1 molecular sieve is prepared by hydrothermal synthesis method. The hydrothermal synthesis conditions are: reaction temperature is 100-160°C, reaction time is 24-72h, and reaction pressure is 0.5-2MPa; S2. Immerse the ZMQ-1 molecular sieve in a solution containing rare earth metals and Group VIII metal salts; S3. Dry the impregnated ZMQ-1 molecular sieve. The drying temperature is 100-120°C and the drying time is 8-12h; S4. Calcinate the dried catalyst. The calcination temperature is 450-600°C and the calcination time is 4-6h; S5. Mix the calcined catalyst with the binder and carry out wet granulation to obtain catalyst particles with a particle size of 1-5mm; S6. Dry and screen the catalyst particles to obtain the final catalyst.

7. The preparation method of a liquefied petroleum gas alkylation reaction catalyst according to claim 6, characterized in that, In the solution in step S2, the metal salts used are at least one of cerium chloride and ammonium molybdate, and the concentration of the metal salts is 0.1 to 1.0 mol / L.

8. The preparation method of a liquefied petroleum gas alkylation reaction catalyst according to claim 6, characterized in that, In step S2, the impregnation time for impregnation is 2-12h and the impregnation temperature is 25-50°C.

9. A method for applying a liquefied petroleum gas alkylation reaction catalyst according to any one of claims 1-5, characterized in that, The said catalyst is used in the liquefied petroleum gas alkylation reaction, the reaction temperature is 200-400°C, the reaction pressure is 1-5MPa, the liquid-gas ratio is 2-10, and the reaction time is 0.5-2h.

10. The application method of a liquefied petroleum gas alkylation reaction catalyst according to claim 9, characterized in that, The said catalyst can be regenerated and reused during the reaction, and its activity is restored by calcination.

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