Efficient catalytic cracking method and system based on ZMQ-1 molecular sieve

Abstract

The invention relates to the field of petrochemical engineering, and discloses an efficient catalytic cracking method and system based on a ZMQ-1 molecular sieve, which takes a heavy oil product subjected to desulfurization and metal impurity removal as a raw material, and performs cracking reaction by using a catalyst taking the ZMQ-1 molecular sieve as a core. The reaction conditions are as follows: the temperature is 450-550 DEG C, the pressure is 0.1-0.3 MPa, the weight ratio of the catalyst to the raw materials is 1: 10-1: 20, and the space velocity is 2-6h <-1 >; and low-carbon olefins, light aromatic hydrocarbons and gasoline fractions are recovered from cracking products through gas-liquid separation, and uncracked heavy oil products can be cyclically subjected to secondary cracking. The system comprises a raw material pretreatment unit, a catalytic cracking unit, a product separation unit and an uncracked component reflux unit. According to the present invention, through the grading pore channel design of the ZMQ-1 molecular sieve and the introduction of the appropriate metal auxiliary agent, the efficient conversion of the heavy oil, the selective generation of the target product and the significant reduction of the coke generation amount are achieved, and the characteristics of green low carbon, high efficiency and energy saving are provided.

Description

Technical Field

[0001] The invention relates to the technical field of petrochemical industry, and in particular to a high-efficiency catalytic cracking method and system based on ZMQ-1 molecular sieve. Background Art

[0002] Catalytic cracking technology is one of the important processes in the field of petrochemicals for converting heavy oil products into light, high-value-added chemicals. In recent years, with the increasing complexity of crude oil quality, heavy raw materials contain a large amount of high molecular weight alkanes, aromatics and heterocyclic compounds, which puts higher requirements on the conversion efficiency of catalytic cracking technology and the selectivity of target products. However, it is difficult for existing catalyst systems to balance efficient conversion and product quality when processing these complex raw materials. Traditional catalysts (such as USY molecular sieves and β-type molecular sieves) mainly rely on smaller pore structures and acidic centers for reactions, which makes it difficult for large molecular raw materials to effectively diffuse and fully contact active sites, resulting in low reaction efficiency and limited product distribution. In addition, traditional catalysts are prone to generate a large amount of coke during the cracking process, which not only reduces the life of the catalyst, but also increases the regeneration frequency and operating costs.

[0003] In order to meet the needs of efficient conversion of complex raw materials, the pore structure, acid distribution and adaptability of reaction conditions of the catalyst are particularly important. Although some improved molecular sieve catalysts have achieved certain performance optimization by adjusting the pore size, they still have obvious deficiencies in light product selectivity and resistance to coke formation. At the same time, the complex preparation process and high regeneration cost also limit the extensiveness of its industrial application.

[0004] Therefore, developing a catalytic cracking catalyst system with higher activity, better selectivity, lower coke production, and adaptability to a variety of complex raw materials has become a key direction for solving the bottleneck of existing technologies. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a high-efficiency catalytic cracking method and system based on ZMQ-1 molecular sieve, which achieves efficient conversion of heavy oil and highly selective production of light hydrocarbons and aromatics by optimizing the pore structure and reaction system of the catalyst, while significantly reducing the amount of coke generated.

[0006] To achieve the above objectives, the present invention is implemented by the following technical scheme: a high-efficiency catalytic cracking method based on ZMQ-1 molecular sieve, comprising the following steps:

[0007] (1) Heavy oil is used as raw material and pre-treated after desulfurization and removal of metal impurities;

[0008] (2) The pretreated raw material is passed into a catalytic cracking unit and cracked using a catalyst with a ZMQ-1 molecular sieve as the core, wherein:

[0009] The ZMQ-1 molecular sieve has 28-membered ring macropores and 10-membered ring micropores;

[0010] (3) Control the reaction temperature to 450-550°C, the pressure to 0.1-0.3 MPa, the catalyst: raw material weight ratio to 1:10 to 1:20, and the space velocity to 2-6 h -1 Catalytic cracking is carried out under the conditions of

[0011] (4) Separate the cracking products into gas and liquid, recover low-carbon olefins, light aromatics and gasoline fractions, and recycle the uncracked heavy oil products for secondary cracking.

[0012] The present invention also provides a high-efficiency catalytic cracking system based on ZMQ-1 molecular sieve, comprising:

[0013] Raw material pretreatment unit, used for heating, desulfurization and removal of metal impurities of raw materials;

[0014] A catalytic cracking unit, including a ZMQ-1 molecular sieve catalyst reactor, is used for cracking at a temperature of 450-550°C and a pressure of 0.1-0.3MPa;

[0015] A product separation unit, used for condensing, gas-liquid separation and fraction recovery of cracking products;

[0016] Catalyst regeneration unit is used to remove coke on the catalyst surface and regulate the acid center.

[0017] The present invention provides a high-efficiency catalytic cracking method and system based on ZMQ-1 molecular sieve, which has the following beneficial effects:

[0018] 1. The present invention effectively improves the cracking conversion rate of heavy oil by adopting the hierarchical pore structure of ZMQ-1 molecular sieve and combining it with appropriate acid distribution. Compared with traditional catalysts, the present invention can more efficiently crack macromolecules such as long-chain alkanes and polycyclic aromatic hydrocarbons, improve the conversion efficiency of target products, and is particularly suitable for heavy raw materials such as vacuum gas oil and petroleum tar.

[0019] 2. Through the size selectivity of the micropores of the ZMQ-1 molecular sieve to the product molecules, the present invention significantly increases the production ratio of light aromatics and low-carbon olefins. At the same time, by introducing metal additives, the selectivity of dehydrogenation aromatization and low-carbon olefin production is further enhanced, so that the quality and yield of light hydrocarbon products are significantly optimized.

[0020] 3. The present invention introduces an appropriate amount of promoter into the catalyst, inhibits the polymerization reaction through hydrogenation, reduces the generation of coke precursors, and optimizes the acid distribution to avoid excessive cracking reactions. Compared with traditional catalysts, the coke generation of the present invention is significantly reduced, thereby extending the service life of the catalyst and reducing the regeneration frequency and related costs.

[0021] 4. The present invention can achieve efficient catalytic cracking at relatively low temperature, low pressure and high space velocity. The adaptability to such harsh reaction conditions demonstrates the high activity and stability of ZMQ-1 molecular sieve, further reduces the energy consumption and cost of industrial operation, and improves the flexibility of equipment operation.

[0022] 5. The present invention realizes a green and low-carbon cracking process by reducing coke generation and energy consumption while increasing the yield of the target product. The high selectivity of the product not only reduces the need for processing by-products, but also optimizes the utilization efficiency of raw materials, showing significant environmental friendliness and economic benefits.

[0023] 6. The ZMQ-1 molecular sieve catalyst of the present invention has a wide range of raw material adaptability, including vacuum gas oil, petroleum tar, heavy crude oil and other complex oil products, and can achieve the optimization of different target products by adjusting the reaction conditions and the type of catalyst additives. This flexibility meets the production needs of diversified and high value-added products in the petrochemical industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a method flow diagram of the present invention;

[0025] Figure 2 It is a schematic diagram of the system structure of the present invention.

[0026] Among them, 10, raw material pretreatment unit; 20, catalytic cracking unit; 30, product separation unit; 40, catalyst regeneration unit. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Please see attached Figure 1The present invention provides a high-efficiency catalytic cracking method based on ZMQ-1 molecular sieve, which realizes high-efficiency cracking and conversion of heavy oil products under optimized reaction conditions by using a ZMQ-1 molecular sieve catalyst with a unique structure. The method can significantly improve the yield of light olefins (such as ethylene, propylene), light aromatics and gasoline fractions, and minimize the amount of coke generated, while extending the catalyst life, and realizing low-carbon, energy-saving and high-efficiency industrial applications.

[0029] like Figure 1 As shown, the efficient catalytic cracking method based on ZMQ-1 molecular sieve may include the following steps:

[0030] S1. Pre-treating heavy oil raw materials to desulfurize and remove metal impurities;

[0031] S2, the pretreated raw material enters the catalytic cracking unit and is cracked using a catalyst with ZMQ-1 molecular sieve as the core;

[0032] S3, completing catalytic cracking under set conditions;

[0033] S4. Separate the cracking products into gas and liquid, recover the target products and circulate the uncracked heavy oil products for secondary cracking.

[0034] Each step of the present invention is described in detail below.

[0035] In this embodiment, the main purpose of step S1 is to perform necessary pretreatment on heavy oil products to improve the efficiency of the subsequent catalytic cracking process and protect the catalyst active center from contamination. Heavy oil products mainly include but are not limited to complex polymer raw materials such as vacuum gas oil (VGO), vacuum residue oil and coking heavy oil.

[0036] Specifically, the pretreatment steps include the following process contents:

[0037] As an option, the heavy oil needs to be mildly hydrotreated during the pretreatment process, mainly to remove sulfides and metal impurities therein. Exemplarily, the process can be carried out at a temperature range of 200-350°C, and the hydrogenation pressure is controlled at 0.5-3.0MPa. The catalyst used can be a cobalt sulfide-molybdenum catalyst or other conventional hydrodesulfurization catalyst to ensure effective removal of sulfides to less than 100ppm, while reducing the heavy metal content to a level acceptable to the catalyst.

[0038] In a possible implementation, the crude oil can be heated to 300-400°C after hydrodesulfurization to reduce its viscosity for subsequent processing. It should be noted that the heating step not only reduces the fluidity of the raw material, but also reduces the risk of deposition of some polymers on the catalyst surface.

[0039] In specific implementation, suspended impurity particles can be further removed by filtering or sedimentation. For example, tiny solid particles in the raw materials can be removed by multi-stage filters, and the particle size is controlled to be less than 20 microns to reduce the wear of subsequent reactors and catalysts.

[0040] In some embodiments, for heavy oil products with high sulfur or high metal content, a staged desulfurization process may be considered, for example, removing soluble sulfides at a lower temperature (200-250°C) in the first stage and removing the remaining sulfides and metal impurities at a higher temperature (300-350°C) in the second stage.

[0041] It should be noted that the pretreatment step is not only to improve the chemical properties of the raw materials, but also to adjust the viscosity and fluidity of the raw materials by adding appropriate amounts of light hydrocarbons (such as propane or butane). The specific addition ratio is determined according to the properties of the raw materials, generally between 1-5wt%.

[0042] It is understandable that for a specific crude oil product, the pretreatment process can be appropriately adjusted according to its composition. For example, for a raw material containing more polycyclic aromatic hydrocarbons, the hydrogenation reaction time can be increased to improve the desulfurization and demetallization efficiency; while for a low-sulfur raw material, heating and filtering can be performed directly to simplify the process.

[0043] It should be further emphasized that any desulfurization, heating or filtering equipment used in this step should meet the continuity requirements of industrial operation. For example, the hydrodesulfurization unit can adopt a fixed bed or moving bed design to ensure the efficiency and stability of large-scale raw material processing.

[0044] In this embodiment, the purpose of step S2 is to send the pretreated heavy oil product to the catalytic cracking unit, and use the catalyst system with ZMQ-1 molecular sieve as the core to carry out catalytic cracking reaction on the raw material. Through the unique pore structure and regulated acid center of ZMQ-1 molecular sieve, the cracking and isomerization reaction path of macromolecular oil products is optimized, and the yield of light olefins and light aromatics is increased.

[0045] Specifically, the ZMQ-1 molecular sieve catalyst is the core of the present invention, which has a 28-membered ring ultra-large channel (pore size of about 23.11) and a 10-membered ring medium-micro channel (pore size range of 5.44-5.81). As an option, the 28-membered ring channel provides sufficient diffusion space and activation sites for macromolecular aromatics and long-chain alkanes, while the 10-membered ring medium-micro channel promotes further cracking of intermediates to generate light olefins through size selectivity.

[0046] In one possible implementation, the acidic center of the ZMQ-1 molecular sieve is regulated by introducing trivalent framework elements (such as aluminum and gallium) and non-silicon tetravalent elements (such as germanium and titanium), forming uniformly distributed strong and weak acidic points. This acid distribution enables the catalyst to effectively activate the CC bond, which not only promotes the cracking reaction but also inhibits side reactions (such as coke formation). It should be noted that the acid strength and distribution of the ZMQ-1 molecular sieve can be precisely controlled by adjusting the silicon / aluminum ratio (or other framework element ratio).

[0047] In some embodiments, in order to further improve the catalyst performance, a metal promoter such as nickel, molybdenum or vanadium may be loaded on the surface of the ZMQ-1 molecular sieve, and the loading amount is generally controlled at 0.5-5wt%. For example, the nickel promoter mainly enhances the hydrocracking performance, while molybdenum and vanadium are more suitable for cracking polycyclic aromatic hydrocarbons.

[0048] It is understood that the catalytic cracking unit can adopt a fluidized bed reactor or a fixed bed reactor, and the specific form depends on the process requirements. In the fluidized bed, the ZMQ-1 molecular sieve catalyst circulates in the form of fine particles and is fully in contact with the oil raw material; while in the fixed bed, the catalyst realizes continuous processing of the raw material in the form of a fixed bed layer. It should be noted that the selection of an appropriate reactor form can be adjusted according to the composition of the raw material and the target product.

[0049] For example, heavy oil is pumped into the cracking unit by a high-pressure pump and then contacts a catalyst heated to the process temperature. In the reactor, the oil molecules first diffuse to the active center through the 28-membered ring channel of the ZMQ-1 molecular sieve, and are broken into intermediate chain hydrocarbons under the action of the acidic center. Subsequently, these intermediate chain hydrocarbons further enter the micropores in the 10-membered ring, undergo secondary cracking and isomerization reactions, and generate low-carbon olefins and light aromatics.

[0050] As an option, a multi-stage reaction bed can be set inside the reactor, and the catalyst characteristics used in each stage of the reaction bed can be different. For example, the catalyst in the first stage bed is mainly used for macromolecular cracking, while the catalyst in the second stage bed is used for selective regulation of intermediate products, thereby realizing step-by-step optimization of the cracking path.

[0051] It should be further emphasized that the ratio of catalyst to oil products in the catalytic cracking process is controlled at 1:10 to 1:20 (weight ratio). This ratio not only ensures the full cracking of oil products, but also minimizes the amount of catalyst used and reduces the overall cost.

[0052] In some embodiments, the catalytic cracking unit can be equipped with an online gas chromatograph (GC) or a mass spectrometer (MS) for real-time monitoring to analyze product composition and reaction conversion. Exemplarily, these online monitoring devices can dynamically adjust the reaction conditions through a feedback mechanism, such as optimizing temperature, pressure or catalyst flow rate to ensure efficient generation of the target product.

[0053] In this embodiment, the purpose of step S3 is to achieve efficient cracking of heavy oil products and highly selective generation of light products by optimizing the catalytic cracking reaction conditions. The core of this step is to control key parameters such as reaction temperature, pressure, catalyst dosage and space velocity, and give full play to the structural and performance advantages of ZMQ-1 molecular sieve catalyst.

[0054] Specifically, the catalytic cracking reaction is carried out in a temperature range of 450-550°C, preferably 450-500°C. As an option, this temperature range can both ensure the high efficiency of the catalyst and reduce the occurrence of side reactions (such as coke formation) at high temperatures. It should be noted that the high thermal stability of the ZMQ-1 molecular sieve ensures that it maintains structural integrity and acidic activity for a long time in the range of 450-550°C.

[0055] In a possible implementation, the reaction pressure is controlled at 0.1-0.3 MPa, preferably normal pressure or slightly positive pressure (0.1 MPa). Exemplarily, low pressure or normal pressure conditions facilitate rapid evaporation and diffusion of the crude oil into the pore system of the catalyst, while reducing equipment investment and operating costs.

[0056] The weight ratio of catalyst to raw material is controlled at 1:10 to 1:20. It should be noted that this ratio not only reduces the amount of catalyst used and improves economic efficiency, but also reduces the amount of coke generated during the cracking process while ensuring the activity of the catalyst. As an option, the catalyst can be fully contacted with the raw oil in the form of a fixed bed or fluidized particles, and the specific form can be adjusted according to industrial production needs.

[0057] In some embodiments, the reaction space velocity (LHSV) is controlled at 2-6h -1 , preferably 3-5h -1 Specifically, under high space velocity conditions, the crude oil can be cracked in a short time, which reduces the carbon deposition pressure on the catalyst surface and improves the processing capacity of the device. It should be noted that by dynamically adjusting the space velocity, efficient reaction optimization under different raw materials or target product conditions can be achieved.

[0058] Exemplarily, heavy oil products are preheated and sent to the reactor to fully contact with the ZMQ-1 molecular sieve catalyst heated to the process temperature. In the reactor, the macromolecular raw materials first diffuse and activate in the 28-membered ring super-large pores, and the CC bond cleavage reaction occurs through the catalytic action of the acidic center of the catalyst to generate intermediate products (such as medium-chain alkanes, cycloalkanes, etc.). Subsequently, these intermediate products enter the micropores in the 10-membered ring and are further cracked to generate target products (such as low-carbon olefins such as ethylene and propylene, and light aromatics).

[0059] It should be further emphasized that the uniform distribution and strength of the catalyst acid center are crucial to the selectivity of the target product during the reaction. In one possible implementation, the ZMQ-1 molecular sieve regulates the framework acidity by introducing aluminum or germanium to form a suitable ratio of strong and weak acids, which not only promotes the cracking reaction but also inhibits the occurrence of side reactions.

[0060] It is understood that in order to improve the stability and efficiency of the catalytic cracking process, the temperature, pressure and product composition of the cracking reaction can be monitored in real time by an online monitoring system (such as a gas chromatograph GC and a mass spectrometer MS). These monitoring data can be used to feedback and adjust the reaction conditions to optimize the generation of the target product.

[0061] In some embodiments, in order to further improve the efficiency of the system, the reactor can be designed as a multi-stage reaction bed. Specifically, the catalyst of the first-stage reaction bed is mainly used to crack macromolecules, while the catalyst of the second-stage reaction bed focuses on the selective regulation of intermediate products, thereby maximizing the yield of light olefins.

[0062] In this embodiment, the purpose of step S4 is to perform efficient gas-liquid separation and component recovery on the catalytic cracking products, while realizing the recycling of uncracked heavy oil products, so as to improve resource utilization efficiency and ensure high selectivity of target products.

[0063] Specifically, the products generated by catalytic cracking reactions are composed of multiple components, including low-carbon olefins (such as ethylene and propylene), light aromatics (such as benzene, toluene, and xylene), gasoline fractions, and uncracked heavy oil products. In order to achieve efficient separation and recovery, the product separation process is designed as a multi-stage process.

[0064] In a possible implementation, the high temperature cracking product at the reactor outlet first passes through a cooling device to preliminarily separate the gas phase component from the liquid phase component. Exemplarily, the cooling temperature is controlled within the range of 40-60°C so that the light olefins remain in the gas phase, while the gasoline fraction and heavier components are separated in the liquid phase. It should be noted that the cooling device can be a shell and tube heat exchanger or other industrial cooling equipment.

[0065] As an option, the gas phase after cooling is further separated by compression and distillation to recover the target products such as ethylene and propylene. Specifically, the recovery of light olefins can adopt a three-stage compression system, after compressing the gas phase components to 0.5-1.0MPa, ethylene and propylene are separated and purified by a cryogenic distillation column.

[0066] In some embodiments, the liquid phase is separated into light aromatics (such as benzene and toluene) and gasoline fractions by atmospheric or vacuum distillation. Specifically, the light aromatics can be recovered as high value-added chemical raw materials, while the gasoline fraction can be directly used as fuel or further refined.

[0067] It should be noted that after the uncracked heavy oil is separated from the bottom of the distillation unit, it is directly returned to the catalytic cracking unit for secondary cracking. The design of recycling the uncracked heavy components significantly improves the utilization rate of raw materials and reduces waste.

[0068] In one possible implementation, in order to improve separation efficiency and product recovery rate, a multi-stage separation device can be equipped in the system. For example, the cooling device in the first stage is used to separate the gas phase and the liquid phase; the distillation tower in the second stage is used to recover light olefins; and the distillation device in the third stage is used to separate light aromatics and gasoline fractions. It should be noted that the multi-stage separation device can be operated continuously to meet the high efficiency requirements of industrial applications.

[0069] It is understood that in the above separation process, in order to prevent the coke particles from affecting the separation equipment, the product gas and liquid flow through the filter device to remove the possible residual solid impurities. Exemplarily, the filter device can use a ceramic filter element or a metal mesh filter element, and its filtration accuracy is controlled at 5-10 microns.

[0070] In some embodiments, in order to optimize energy efficiency, a heat recovery device may be incorporated into the gas-liquid separation and circulation process. For example, heat from the high-temperature product may be recovered through heat exchange to preheat the raw oil or other process heating, thereby reducing overall energy consumption.

[0071] In general, the present invention uses ZMQ-1 molecular sieve as the core catalyst, and utilizes its unique structure of 28-membered ring super-large pores and 10-membered ring micro-pores, as well as regulated acid centers and metal promoters to significantly improve the yield of light olefins, light aromatics and gasoline fractions. At the same time, by strictly controlling the reaction temperature (450-550°C), pressure (0.1-0.3MPa), catalyst: raw material ratio (1:10 to 1:20) and space velocity (2-6h -1 ), combined with efficient multi-stage gas-liquid separation and recycling of uncracked components, it achieves energy conservation and consumption reduction, extends catalyst life and efficient resource utilization, and provides a low-carbon, green and efficient catalytic cracking technology solution for the petrochemical industry.

[0072] Please see attached Figure 2 The present invention also provides a high-efficiency catalytic cracking system based on ZMQ-1 molecular sieve, whose structure and operation mode can effectively realize the high-efficiency cracking conversion of raw materials and optimize the service life of the catalyst. The system is mainly composed of a raw material pretreatment unit 10, a catalytic cracking unit 20, a product separation unit 30 and a catalyst regeneration unit 40. The following will be described in detail according to the function of each unit:

[0073] Raw material pretreatment unit 10

[0074] In an embodiment of the present invention, the main function of the feedstock pretreatment unit 10 is to provide suitable feedstock for the catalytic cracking reaction. The unit includes feedstock heating, desulfurization and metal impurity removal devices. Through this unit, heavy feedstock can be effectively pretreated to reduce impurities in the feedstock and avoid catalyst poisoning or instability during the reaction.

[0075] Heating device: After the raw materials enter the heating device, they are heated to the required temperature (for example, 300-400°C) to reduce the viscosity of the raw materials and promote their subsequent cracking reaction.

[0076] Desulfurization device: The raw materials are desulfurized to remove sulfides to avoid poisoning of catalysts. The desulfurization process can adopt hydrodesulfurization or other conventional desulfurization technologies.

[0077] Metal impurity removal device: Remove metal impurities from raw materials through specific filtration or adsorption technology to prevent these impurities from contaminating the catalyst or reducing the activity of the catalyst during the catalytic cracking reaction.

[0078] Catalytic cracking unit 20

[0079] The catalytic cracking unit 20 is the core part of the whole cracking system, which uses ZMQ-1 molecular sieve catalyst to realize cracking reaction under set temperature and pressure conditions. The unit includes a ZMQ-1 molecular sieve catalyst reactor, a reaction control system and a transmission system.

[0080] ZMQ-1 molecular sieve catalyst reactor: The reactor uses ZMQ-1 molecular sieve catalyst, which has 28-membered ring macropores and 10-membered ring micropores, which can effectively promote the cracking reaction of macromolecular hydrocarbons in the raw materials. The reactor operates in the temperature range of 450-550℃ and the pressure is controlled between 0.1-0.3MPa to ensure the efficient catalytic cracking process.

[0081] Reaction control system: This system is used to control important process parameters such as temperature, pressure and catalyst-to-raw material ratio in the reactor to ensure that the reaction conditions are always optimized and to improve the efficiency and product selectivity of the cracking reaction.

[0082] Catalyst to raw material ratio control system: by adjusting the catalyst to raw material ratio (1:10 to 1:20), and the space velocity (2-6h -1 ), ensuring optimal catalyst utilization efficiency and product distribution.

[0083] Product separation unit 30

[0084] The main function of the product separation unit 30 is to condense, separate gas and liquid, and recover fractions of the products after the cracking reaction. The design of this unit ensures the efficient recovery of target products (such as light olefins, light aromatics, gasoline fractions), and can return incompletely cracked heavy oil products to the catalytic cracking unit 20 for secondary cracking through a reflux device.

[0085] Condensation device: This device cools the cracked gas to condense the low-carbon olefins (such as ethylene, propylene, etc.) at low temperature and separate them. The condensation temperature is generally set between -20℃ and -60℃ to ensure condensation efficiency.

[0086] Gas-liquid separation device: This device is used to effectively separate the light aromatics and gasoline fractions in the condensed cracking products. After the liquid phase and gas phase are separated, the light aromatics and gasoline fractions can be recycled for subsequent production or as chemical raw materials.

[0087] Circulation reflux device: For the heavy oil products that are not completely cracked, the reflux device guides them back to the catalytic cracking unit 20 for secondary cracking treatment. The reflux device can improve the raw material conversion rate, reduce the waste of raw materials, and improve the overall cracking efficiency.

[0088] Catalyst regeneration unit 40

[0089] The main function of the catalyst regeneration unit 40 is to regenerate the catalyst that is contaminated or coked during use, restore its activity, and thus extend the service life of the catalyst. The unit usually includes two steps: coke removal and acid center conditioning.

[0090] Coke removal device: During the catalytic cracking reaction, a certain amount of coke will accumulate on the catalyst surface, resulting in a decrease in catalyst activity. Therefore, the coke on the catalyst surface is removed by combustion or gasification to restore the catalyst performance.

[0091] Acid center conditioning device: After removing the coke, the acid center of the catalyst may change, so acid center conditioning is required to restore the catalyst to the ideal acid state. The conditioning method can include acidification treatment or adding an appropriate amount of chemical additives.

[0092] The entire system works in coordination through an advanced automated control system to ensure the high efficiency of raw material processing, cracking reaction and product recovery. At the same time, the various units of the system are connected through pipelines and pumping devices, and the fluid transmission and reaction process can be carried out in a closed and continuous state, thus ensuring the stability and safety of the process.

[0093] In order to better understand the present invention, the above method is described in detail below in conjunction with specific embodiments.

[0094] Example 1: High-efficiency catalytic cracking method based on ZMQ-1 molecular sieve

[0095] Raw material: Heavy vacuum gas oil (VGO)

[0096] Catalyst: Catalyst with ZMQ-1 molecular sieve as the core and alumina catalyst as the carrier.

[0097] Reaction conditions:

[0098] Reaction temperature: 500℃

[0099] Reaction pressure: 0.2MPa

[0100] Space speed: 4h -1

[0101] Catalyst: raw material ratio: 1:15

[0102] Operation process:

[0103] After the VGO raw material is pretreated and desulfurized and metal impurities are removed, it is passed into the catalytic cracking reaction unit. The reaction is carried out under the above conditions. The catalyst is based on ZMQ-1 molecular sieve and reacts with the raw oil for catalytic cracking. After the cracking products are separated by gas and liquid, the yield of light olefins reaches 20%, the yield of gasoline fraction is 40%, and the yield of light aromatics is 15%.

[0104] Example 2: High-efficiency catalytic cracking method based on ZMQ-1 molecular sieve

[0105] Raw material: vacuum residue

[0106] Catalyst: ZMQ-1 molecular sieve and rare earth metal composite catalyst

[0107] Reaction conditions:

[0108] Reaction temperature: 480℃

[0109] Reaction pressure: 0.15MPa

[0110] Space speed: 3h -1

[0111] Catalyst: raw material ratio: 1:12

[0112] Operation process:

[0113] The pretreated vacuum residue is added to the cracking reaction system and cracked under the action of ZMQ-1 molecular sieve and rare earth metal composite catalyst. The reaction products are recovered through the gas-liquid separation device to recover light olefins, gasoline fractions and part of heavy oil, and then enter the cracking reaction unit again for secondary cracking. Finally, the yield of gasoline fraction is 38%, the yield of light aromatics is 12%, and the uncracked oil is recovered and reprocessed.

[0114] Example 3: High-efficiency catalytic cracking method based on ZMQ-1 molecular sieve

[0115] Raw material: heavy crude oil

[0116] Catalyst: Pure ZMQ-1 molecular sieve

[0117] Reaction conditions:

[0118] Reaction temperature: 530℃

[0119] Reaction pressure: 0.25MPa

[0120] Space speed: 5h -1

[0121] Catalyst: raw material ratio: 1:18

[0122] Operation process:

[0123] After desulfurization and removal of metal impurities, heavy crude oil is passed into the catalytic cracking reaction unit. The reaction is carried out under the above conditions, using pure ZMQ-1 molecular sieve as a catalyst for cracking. Among the gas-liquid separation products after cracking, the yield of light olefins is 25%, and the yield of gasoline fraction is 43%. By recycling the uncracked oil products, the utilization rate of the catalyst and the cracking efficiency are improved.

[0124] Example 4: High-efficiency catalytic cracking method based on ZMQ-1 molecular sieve

[0125] Raw material: petroleum tar

[0126] Catalyst: ZMQ-1 molecular sieve and nano-molybdenum catalyst complex

[0127] Reaction conditions:

[0128] Reaction temperature: 490℃

[0129] Reaction pressure: 0.18MPa

[0130] Space speed: 6h -1

[0131] Catalyst: raw material ratio: 1:14

[0132] Operation process:

[0133] Under the action of ZMQ-1 molecular sieve and nano-molybdenum catalyst complex, petroleum tar raw material was successfully converted into light oil in the cracking reaction. After gas-liquid separation, the yield of light oil products was 50%, the yield of low-carbon olefins was 22%, and the yield of light aromatics was 18%. The uncracked oil was recovered for secondary cracking, which further increased the yield of the product.

[0134] Example 5: High-efficiency catalytic cracking method based on ZMQ-1 molecular sieve

[0135] Raw material: heavy oil (containing a higher proportion of asphaltene)

[0136] Catalyst: ZMQ-1 molecular sieve and multi-metal catalyst

[0137] Reaction conditions:

[0138] Reaction temperature: 470℃

[0139] Reaction pressure: 0.3MPa

[0140] Space speed: 4h -1

[0141] Catalyst: raw material ratio: 1:10

[0142] Operation process:

[0143] During the pretreatment of heavy oil, the quality of the raw materials is optimized by removing sulfur, nitrogen and metal impurities. The cracking reaction is carried out under appropriate temperature, pressure and catalyst: raw material ratio conditions. Under the action of ZMQ-1 molecular sieve and multi-metal catalyst, the yield of light olefins in the oil cracking products is 18%, light aromatics is 16%, and gasoline fraction is 45%. Some uncracked oil products are cracked to obtain higher product yields through secondary cracking.

[0144] Comparative experiment 1:

[0145] Objective: To compare the effects of ZMQ-1 molecular sieve and traditional catalysts (such as USY molecular sieve) on the cracking efficiency of crude oil, light hydrocarbon yield and coke production in the catalytic cracking process.

[0146] Experimental materials:

[0147] Vacuum gas oil (VGO) is used, a typical heavy oil product containing a large amount of aromatic hydrocarbons, cycloparaffins and long-chain alkanes.

[0148] Initial components: VGO sulfur content is 1.5wt%, and metal impurity concentration is 30ppm.

[0149] catalyst:

[0150] Experimental Example 1: A ZMQ-1 molecular sieve catalyst having a structure of 28-membered ring macropores and 10-membered ring micropores was used. The catalyst preparation method is as follows:

[0151] The ZMQ-1 precursor was prepared by sol-gel method using SiO2 and Al2O3 as the main raw materials.

[0152] An appropriate amount of template agent is added to the precursor, and the ZMQ-1 molecular sieve is synthesized through a hydrothermal synthesis process.

[0153] The synthesized ZMQ-1 molecular sieve was calcined at 550°C for 4 hours to remove the template and activate the catalyst.

[0154] Comparative Example 1: USY molecular sieve is used as a traditional catalyst, and the preparation method of the catalyst is as follows:

[0155] USY molecular sieve was prepared by hydrothermal synthesis method using SiO2 and Al2O3 as raw materials.

[0156] During the synthesis process, a template is added and the synthesis is carried out under hydrothermal reaction conditions.

[0157] The calcination temperature was set at 600 °C and the calcination time was 5 h to remove the template and activate the catalyst.

[0158] Reaction conditions: reaction temperature: 500°C, reaction pressure: 0.2MPa, space velocity: 4h -1 , catalyst: raw material ratio: 1:15.

[0159] Reactor: A fixed bed reactor was used, feed rate: 1000 g / h, catalyst volume in the reactor: 200 mL.

[0160] Reaction time: The reaction time for each experiment is 2 hours, and the product separation and analysis are carried out after the experiment.

[0161] Experimental steps:

[0162] 1. Catalyst pretreatment: The catalyst is activated by calcining at 550°C for 4 hours using air fluidization to ensure that the active center of the catalyst is clean and moisture is removed.

[0163] 2. Raw material pretreatment: Desulfurize the VGO raw oil and reduce its sulfur content to less than 0.1wt% using hydrodesulfurization technology. Metal removers are further used to remove metal impurities to ensure that the catalyst is not poisoned by metals.

[0164] 3. Reaction condition setting: The pretreated VGO crude oil was introduced into the fixed bed reactor and adjusted to the required reaction conditions (500°C, 0.2MPa, space velocity 4h -1 ).

[0165] 4. Catalytic cracking reaction: Start the reaction and keep the reaction temperature, pressure and space velocity stable. Monitor the state of the catalyst and the gas and liquid distribution of the product during the reaction. Collect gas and liquid products regularly.

[0166] 5. Product separation and analysis: After the reaction is completed, gas-liquid separation is performed to collect different components such as light hydrocarbons, aromatics, and diesel. The product composition is analyzed using gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). The yield of each product is measured, and the overall raw material conversion rate and selectivity are calculated.

[0167] The experimental results are shown in the following table:

[0168]

[0169]

[0170] According to the results shown in the experimental data table, the performance of Experimental Example 1 (ZMQ-1 molecular sieve catalyst) and Comparative Example 1 (USY catalyst) in the catalytic cracking reaction is significantly different. The specific analysis is as follows:

[0171] 1. Raw material conversion rate

[0172] The average feed conversion rate of Experimental Example 1 is 82.3%, which is significantly higher than 78.4% of Comparative Example 1. This difference shows that the ZMQ-1 molecular sieve exhibits higher catalytic activity in the catalytic cracking process. The ZMQ-1 molecular sieve has a special structure of 28-membered ring ultra-large pores and 10-membered ring micropores, which enables it to crack macromolecular raw materials more effectively. In contrast, the smaller pore structure of the USY molecular sieve limits its cracking efficiency of macromolecular raw materials in the cracking process, resulting in its lower conversion rate.

[0173] 2. Yield of light hydrocarbons and low carbon olefins

[0174] In terms of light hydrocarbon yield, the average result of Experimental Example 1 is 45.6%, which is significantly higher than 38.7% of Comparative Example 1. This improvement is mainly attributed to the special pore structure and excellent acid properties of ZMQ-1 molecular sieve. ZMQ-1 molecular sieve can better catalyze the cracking reaction of hydrocarbon molecules, especially for the production of low molecular weight olefins and aromatics with higher selectivity.

[0175] In terms of the average yield of light olefins (ethylene and propylene), Experimental Example 1 also performed well, reaching 23.4%, while Comparative Example 1 was only 18.5%. This shows that ZMQ-1 molecular sieve can more effectively generate light light olefins in cracking reactions, especially under low temperature and high space velocity reaction conditions, this advantage is more obvious. This highly selective light olefin generation further improves the efficiency of the present invention in cracking reactions and helps to produce high value-added olefin products.

[0176] 3. Gasoline fraction yield

[0177] The average gasoline fraction yield of Experimental Example 1 is 18.1%, which is better than 15.2% of Comparative Example 1. This difference is also due to the fact that the ZMQ-1 molecular sieve can more effectively promote the cracking of heavy oil products through its ultra-large pores and medium-micro pore structures, generating more gasoline and diesel-type light oil products. Due to the small pore size of the USY molecular sieve, relatively more heavy products are generated in the cracking reaction, resulting in a lower yield of the gasoline fraction.

[0178] 4. Coke production

[0179] In terms of coke generation, the average coke generation of Experimental Example 1 is 5.2%, which is lower than 7.3% of Comparative Example 1. The reduction in coke generation shows that the ZMQ-1 molecular sieve can effectively inhibit side reactions (such as aromatization and polymerization reactions) in the cracking process and reduce the generation of coke. This feature is very important in the catalytic cracking process because coke not only reduces the service life of the catalyst, but also may affect the quality and subsequent processing of the product. Therefore, the ZMQ-1 molecular sieve can significantly reduce the generation of coke while improving the conversion rate and the yield of light hydrocarbons, thereby optimizing the economic and environmental benefits of the cracking reaction.

[0180] From the experimental results, the ZMQ-1 molecular sieve catalyst used in the present invention has significant advantages in many aspects compared with the traditional USY molecular sieve catalyst. Specifically:

[0181] 1. Advantages of pore structure: ZMQ-1 molecular sieve has super large pores of 28-membered rings and medium and micro pores of 10-membered rings, which can effectively promote the cracking reaction of macromolecular crude oil and increase the production of low molecular weight light hydrocarbons. The uniqueness of this pore structure is not available in traditional USY molecular sieves, which have relatively small pores, limiting the conversion of macromolecular crude oil and the production of light products.

[0182] 2. Efficient cracking and selectivity control: The ZMQ-1 molecular sieve catalyst of the present invention not only improves the conversion rate of raw materials, but also performs outstandingly in the generation of light hydrocarbons, low-carbon olefins and gasoline fractions. This shows that the ZMQ-1 molecular sieve has better cracking efficiency and selectivity control ability, and can more accurately control the distribution of cracking products, thereby improving the quality and yield of the products.

[0183] 3. Lower coke generation: ZMQ-1 molecular sieve can effectively reduce coke generation, which is crucial to the long-term stability and economy of the catalyst. The reduction of coke means that the activity of the catalyst is better maintained during the long-term reaction process, which prolongs the service life of the catalyst, reduces the regeneration frequency and cost, and thus can reduce operating costs in practical applications.

[0184] Through the above analysis, it can be concluded that the method of catalytic cracking using ZMQ-1 molecular sieve catalyst in the present invention is significantly superior to the traditional USY molecular sieve catalyst in terms of reaction efficiency, product selectivity, coke formation inhibition, etc. This innovative catalyst not only improves the cracking efficiency, but also optimizes the economic and environmental benefits in the cracking process, and has good industrial application prospects.

[0185] Comparative experiment 2:

[0186] Objective: To compare the catalytic cracking performance of ZMQ-1 molecular sieve with that of β-type molecular sieve and to verify the role of the unique 28-membered ring super-large pores and 10-membered ring micro-pores of ZMQ-1 molecular sieve in improving the catalytic cracking efficiency and light product yield.

[0187] Experimental materials:

[0188] Vacuum residue oil (VGO), a typical heavy oil product, is used, which contains a large amount of polycyclic aromatic hydrocarbons and long-chain alkanes.

[0189] Initial composition: VGO with a sulfur content of 1.2 wt% and a metal impurity concentration of 25 ppm.

[0190] catalyst:

[0191] Experimental Example 2 uses a ZMQ-1 molecular sieve catalyst having a structure of 28-membered ring macropores and 10-membered ring micropores, and the preparation method is the same as that of Experimental Example 1.

[0192] Comparative Example 2: Using a β-type molecular sieve catalyst (12-membered ring structure).

[0193] Preparation method:

[0194] A silicon source (fumed silica) and an aluminum source (sodium aluminate) were mixed to prepare a silicon-aluminum precursor solution with a Si / Al ratio of 30:1.

[0195] Tetraethylammonium cation was added as a template, and the hydrothermal crystallization conditions were 160°C and the time was 7 days.

[0196] The crystallized product is centrifuged, washed and dried, and calcined at 600°C for 5 hours to remove the template and activate the molecular sieve.

[0197] Reaction conditions: reaction temperature: 480°C, reaction pressure: 0.1MPa, space velocity: 3h -1 , catalyst: raw material ratio: 1:12.

[0198] Reactor: A fixed bed reactor was used, feed rate: 800 g / h, catalyst volume in the reactor: 150 mL.

[0199] Reaction time: The reaction time for each experiment is 3 hours, and the product separation and analysis are carried out after the experiment.

[0200] Experimental steps:

[0201] 1. Catalyst pretreatment: The catalyst was activated by calcining at 550°C (ZMQ-1 molecular sieve) and 600°C (β-type molecular sieve) for 6 hours and 5 hours respectively to ensure the removal of moisture and impurities.

[0202] 2. Raw material pretreatment: Use hydrodesulfurization technology to reduce the sulfur content of vacuum residue to below 0.1wt%, and then remove metal impurities to ensure that the catalyst activity is not affected by poisoning.

[0203] 3. Setting of reaction conditions: Pump the treated vacuum residue oil into the fixed bed reactor and operate it according to the set reaction temperature, pressure and space velocity conditions.

[0204] 4. Catalytic cracking reaction: The cracking reaction is carried out under the condition of maintaining stable temperature and pressure. The state of the catalyst in the reaction is monitored and the amount of gas and liquid products generated is recorded.

[0205] 5. Product separation and analysis: After the reaction is completed, the products are collected by a gas-liquid separation device, and the light hydrocarbon and aromatic components are analyzed by gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC), respectively. The heavy oil conversion rate, light aromatic yield and low-carbon olefin product distribution are measured, and the catalytic efficiency is calculated.

[0206] The experimental results are shown in the following table:

[0207]

[0208] According to the experimental results of comparative experiment 2, there is a significant difference in performance between experimental example 2 (ZMQ-1 molecular sieve catalyst) and comparative example 2 (β-type molecular sieve catalyst) in the catalytic cracking process. The method of the present invention realizes efficient catalytic cracking reaction through the hierarchical pore structure of ZMQ-1 molecular sieve, greatly improves the raw material conversion rate and target product yield, and significantly reduces the amount of coke generated. The specific analysis is as follows:

[0209] 1. Significant improvement in heavy oil conversion rate

[0210] The heavy oil conversion rate of Experimental Example 2 reached 84.5%, which was 6.4 percentage points higher than that of Comparative Example 2 (78.1%). This result is due to the unique 28-membered ring ultra-large pore structure of the ZMQ-1 molecular sieve, which enables the macromolecular polycyclic aromatic hydrocarbons and long-chain alkanes in the raw materials to diffuse smoothly into the interior of the catalyst and fully contact with the active sites. In contrast, the 12-membered ring pores of the β-type molecular sieve limit the diffusion efficiency of the macromolecular raw materials, resulting in the inability to effectively crack some macromolecules.

[0211] The ultra-large pores of the ZMQ-1 molecular sieve not only improve the applicability of the catalyst to macromolecular raw materials, but also reduce the diffusion resistance of the cracking reaction, thereby achieving a higher conversion rate. This pore structure design makes the method of the present invention show unique advantages in processing heavy oil products with high molecular weight and complex structure.

[0212] 2. Significant optimization of light aromatics yield

[0213] In terms of the yield of light aromatics, Experimental Example 2 reached 22.3%, which was nearly 4 percentage points higher than 18.5% of Comparative Example 2. The production of light aromatics (such as benzene, toluene, and xylene) involves complex cracking and reforming reactions, and the hierarchical pore design of ZMQ-1 molecular sieve (28-membered ring super-large pores and 10-membered ring micro-pores) plays a key role in this process.

[0214] 28-membered ring channel: provides ample reaction space for heavy oil molecules, making the large molecules more efficient in cracking into intermediate products (such as medium-chain alkanes).

[0215] 10-membered ring channels: The mesopores further selectively crack the intermediates and improve the selective generation of light aromatics by limiting the size effect.

[0216] In contrast, the β-type molecular sieve has only a single 12-membered ring channel, and its subsequent cracking and selective regulation capabilities for intermediate products are weak, resulting in a low yield of light aromatics.

[0217] 3. Substantial increase in the yield of low-carbon olefins

[0218] In terms of the yield of low-carbon olefins (such as ethylene and propylene), Experimental Example 2 showed a significant advantage, reaching 26.7%, which was 5.5 percentage points higher than 21.2% of Comparative Example 2. This shows that the hierarchical pore structure of the ZMQ-1 molecular sieve not only promotes the initial cracking of macromolecules, but also effectively improves the selectivity of the target olefin product.

[0219] This performance improvement is due to the following characteristics of ZMQ-1 molecular sieve:

[0220] Optimization of acidity distribution: ZMQ-1 molecular sieve achieves moderate acidity strength by adjusting the silicon / aluminum ratio, making it more active in cracking reactions while inhibiting the occurrence of side reactions (such as polymerization reactions).

[0221] Pore ​​matching: The micropores in the 10-membered ring are size-selective for low-carbon olefins, effectively inhibiting the formation of larger molecular weight products, thereby increasing the yield of olefins.

[0222] In contrast, β-type molecular sieves have a significant disadvantage in the yield of light olefins due to their smaller pore size and lack of ability to selectively control the graded intermediate products.

[0223] 4. Significant reduction in coke generation

[0224] The coke production in Experimental Example 2 was 5.8%, significantly lower than 7.2% in Comparative Example 2. The reduction in coke production is mainly attributed to the fact that the ultra-large pores of the ZMQ-1 molecular sieve reduce the probability of side reactions in the cracking reaction, especially polymerization reactions and coke deposition reactions. This performance not only extends the service life of the catalyst, but also greatly reduces the frequency of catalyst regeneration, thereby improving the economic efficiency of the reaction.

[0225] In contrast, due to the limited pore size of β-zeolite, macromolecules are prone to polymerization on the catalyst surface to form coke, resulting in a high amount of coke. This coke deposition may further poison the active sites of the catalyst and reduce the catalytic efficiency.

[0226] Comparative experiment 3:

[0227] Objective: To compare the catalytic performance of pure ZMQ-1 molecular sieve and supported nickel promoter, and to verify the effect of metal promoter on improving cracking efficiency, light aromatics yield and reducing coke generation.

[0228] Experimental raw materials: petroleum tar, a heavy oil product containing high concentrations of aromatic hydrocarbons, long-chain alkanes and impurities (sulfur content of 2.5wt%, metal impurity concentration of 50ppm).

[0229] catalyst:

[0230] Experimental Example 3: ZMQ-1 molecular sieve catalyst loaded with 0.5 wt% nickel

[0231] Preparation method:

[0232] 1. Use the prepared pure ZMQ-1 molecular sieve as the carrier. The preparation method of ZMQ-1 molecular sieve is:

[0233] A silicon source (fumed silica) and an aluminum source (aluminum nitrate) were mixed to prepare a gel at a Si / Al molar ratio of 20:1.

[0234] A diquaternary phosphorus template (cyclohexyl substituent) was added and hydrothermal crystallization was carried out at 180°C for 10 days.

[0235] After washing and drying, the sintered film was calcined at 550°C for 4 hours to remove the template and activate the film.

[0236] 2. Nickel metal loading method:

[0237] The ZMQ-1 molecular sieve was mixed with 0.5 mol / L nickel nitrate solution, stirred for 12 hours and then dried.

[0238] The ZMQ-1 molecular sieve loaded with 0.5 wt % nickel was prepared by calcining at 400° C. for 3 hours.

[0239] Comparative Example 3: Pure ZMQ-1 molecular sieve catalyst

[0240] Preparation method:

[0241] The same ZMQ-1 molecular sieve preparation method was used without the subsequent metal loading step.

[0242] Reaction conditions: reaction temperature: 490°C, reaction pressure: 0.15MPa, space velocity: 4h -1 , catalyst: raw material ratio: 1:18.

[0243] Reactor: fixed bed reactor, feed rate: 800 g / h, catalyst volume in the reactor: 150 mL.

[0244] Reaction time: The reaction time for each experiment is 2 hours, and the product separation and analysis are carried out after the experiment.

[0245] Experimental steps:

[0246] 1. Catalyst pretreatment: The catalyst of Experimental Example 3 was activated by calcining at 400°C for 3 hours; the catalyst of Comparative Example 3 was activated by calcining at 550°C for 4 hours. Ensure the cleanliness of the active center of the catalyst.

[0247] 2. Raw material pretreatment: desulfurize petroleum tar to a sulfur content of less than 0.5wt%, and remove some metal impurities at the same time.

[0248] 3. Reaction condition setting: The pretreated petroleum tar is fed into a fixed bed reactor and operated at 490°C and 0.15MPa.

[0249] 4. Catalytic cracking reaction: start the reaction, keep the temperature, pressure and space velocity stable, and monitor the changes in gas and liquid phases during the reaction.

[0250] 5. Product separation and analysis: After the reaction is completed, the product is collected by a gas-liquid separation device. The gas phase components (low-carbon olefins) are analyzed by gas chromatography-mass spectrometry (GC-MS); the liquid phase components (light aromatics) are analyzed by high-performance liquid chromatography (HPLC); the coke production and the total raw material conversion rate are measured.

[0251] The experimental results are shown in the following table:

[0252]

[0253] According to the experimental results of comparative experiment 3, there is a significant difference in catalytic cracking performance between experimental example 3 (ZMQ-1 molecular sieve catalyst loaded with 0.5wt% nickel) and comparative example 3 (pure ZMQ-1 molecular sieve catalyst). The present invention introduces a nickel metal promoter, which synergizes with the hierarchical pore structure of the ZMQ-1 molecular sieve, significantly improves the conversion efficiency of heavy oil, the yield of light aromatics and low-carbon olefins, and significantly reduces the amount of coke generated.

[0254] 1. Significant improvement in heavy oil conversion rate

[0255] The heavy oil conversion rate of Experimental Example 3 reached 88.7%, which was 6.6 percentage points higher than 82.1% of Comparative Example 3. This significant improvement was due to the introduction of the nickel additive, which effectively reduced the cracking activation energy of the CC bond in the heavy oil molecule through its hydrocracking function.

[0256] Nickel metal provides hydrogenation sites on the catalyst surface, activates hydrogen elements in the molecules, inhibits the occurrence of macromolecular polymerization reactions, and thus promotes the efficient conversion of macromolecules to small molecules.

[0257] In contrast, Comparative Example 3 (pure ZMQ-1 molecular sieve) lacks the hydrogenation function of nickel metal and relies only on the acid center of the molecular sieve for cracking. Although it has certain activity, its cracking efficiency for petroleum tar with high asphaltene content is relatively low.

[0258] 2. Improvement of light aromatics yield

[0259] The yield of light aromatics in Experimental Example 3 was 26.4%, which was 3.9 percentage points higher than 22.5% in Comparative Example 3. The introduction of nickel additive has two promoting effects on the formation of light aromatics:

[0260] Dehydrogenation aromatization function: Nickel additives can effectively catalyze the dehydrogenation of cycloalkanes to generate aromatics. Combined with the micropore structure of the 10-membered ring of ZMQ-1 molecular sieve, this function can further improve the selectivity of aromatics.

[0261] Synergistic effect of acidic centers: The acidic sites of ZMQ-1 zeolite provide intermediates through catalytic cracking, while the nickel additive can selectively promote the formation and stability of aromatic precursors.

[0262] In contrast, although the pure ZMQ-1 molecular sieve in Comparative Example 3 has a higher graded pore diffusion performance, it lacks the nickel metal dehydrogenation aromatization function, resulting in a low production of light aromatics.

[0263] 3. Significant improvement in the yield of light olefins

[0264] The yield of low-carbon olefins (ethylene, propylene) in Experimental Example 3 reached 28.9%, which was 4.2 percentage points higher than 24.7% in Comparative Example 3. This indicates that a synergistic effect is formed between the nickel additive and the ZMQ-1 molecular sieve:

[0265] Nickel additives can stabilize intermediate products during the cracking process through hydrogenation function, thereby reducing unnecessary side reactions (such as further polymerization).

[0266] The 28-membered ring ultra-large pores of the ZMQ-1 molecular sieve effectively process large molecular raw materials, while the 10-membered ring micropores are size-selective for the production of light olefins, thus ensuring the highly selective production of olefins.

[0267] In Comparative Example 3, pure ZMQ-1 molecular sieve lacks the hydrogenation function of nickel metal. Although it can still produce a certain amount of light olefins, its selectivity and efficiency are lower than those of the nickel-loaded catalyst.

[0268] 4. Reduction of coke generation

[0269] The coke production in Experimental Example 3 is 5.3%, which is significantly lower than 6.7% in Comparative Example 3. The reduction of coke production by nickel additive is mainly achieved through the following mechanisms:

[0270] Hydrogenation inhibits side reactions: Nickel additives inhibit the polymerization reaction of raw material molecules and intermediate products by activating hydrogen molecules, thereby reducing the formation of coke precursors.

[0271] Acid site regulation: The introduction of nickel additive can adjust the acid distribution of ZMQ-1 molecular sieve, avoid excessive cracking reaction caused by excessive acid sites, and thus reduce the formation of coke.

[0272] In contrast, although the acid sites of the pure ZMQ-1 molecular sieve in Comparative Example 3 can carry out effective cracking reactions, their ability to control the polymerization side reactions of macromolecules is relatively weak, resulting in a higher amount of coke generated.

[0273] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-efficiency catalytic cracking method based on ZMQ-1 molecular sieve, characterized in that: The following steps are involved: (1) Heavy oil is used as raw material and pre-treated after desulfurization and removal of metal impurities; (2) The pretreated raw material is passed into a catalytic cracking unit and cracked using a catalyst with a ZMQ-1 molecular sieve as the core, wherein: The ZMQ-1 molecular sieve has 28-membered ring macropores and 10-membered ring micropores; (3) Control the reaction temperature to 450-550°C, the pressure to 0.1-0.3 MPa, the catalyst: raw material weight ratio to 1:10 to 1:20, and the space velocity to 2-6 h -1 Catalytic cracking is carried out under the conditions of (4) Separate the cracking products into gas and liquid, recover low-carbon olefins, light aromatics and gasoline fractions, and recycle the uncracked heavy oil products for secondary cracking.

2. A high-efficiency catalytic cracking method based on ZMQ-1 molecular sieve according to claim 1, characterized in that: The heavy oil product is vacuum gas oil, vacuum residue oil or coking heavy oil, which is mildly hydrogenated at 200-350° C. to remove sulfide and heavy metal impurities.

3. A high-efficiency catalytic cracking method based on ZMQ-1 molecular sieve according to claim 1, characterized in that: The ZMQ-1 molecular sieve catalyst is prepared by the following steps: A synthetic gel consisting of a silicon source, a trivalent skeleton element source, a diquaternary phosphorus cation template and a fluorine-containing mineralizer is prepared, wherein the molar ratio of SiO2:X2O3:M2O is 1:0.1-0.5:0.1-1; The synthesized gel is crystallized under hydrothermal conditions at 50-250° C. for 5-15 days and then calcined to remove the organic template.

4. A high-efficiency catalytic cracking method based on ZMQ-1 molecular sieve according to claim 3, characterized in that: The calcination temperature of the catalyst is 550-700° C., and the calcination time is 6-12 hours.

5. A high-efficiency catalytic cracking method based on ZMQ-1 molecular sieve according to claim 3, characterized in that: The catalyst was optimized by the following steps: Introducing trivalent elements and non-silicon tetravalent elements into the ZMQ-1 molecular sieve framework to enhance the activation ability of its acidic center; A metal promoter is loaded on the surface of the molecular sieve, wherein the metal promoter is at least one of nickel, molybdenum and vanadium.

6. A high-efficiency catalytic cracking method based on ZMQ-1 molecular sieve according to claim 1, characterized in that: The reaction conditions of the catalytic cracking also include: Temperature range 450-500℃, pressure range 0.1-0.2MPa, space velocity 3-5h -1 .

7. A high-efficiency catalytic cracking method based on ZMQ-1 molecular sieve according to claim 1, characterized in that: The coke produced during the cracking process is processed by the following steps: The catalyst is regenerated by burning away the coke in an oxygen environment at 550-600°C; After regeneration, 600-700°C steam is introduced to condition the acid center.

8. A high-efficiency catalytic cracking method based on ZMQ-1 molecular sieve according to claim 1, characterized in that: The cracked products are processed by a three-stage separation device, specifically including: (1) Condensation and recovery of light olefins; (2) Gas-liquid separation to recover light aromatics and gasoline fractions; (3) Circulating uncracked heavy oil products with large molecular weight to the reactor for secondary cracking.

9. A high-efficiency catalytic cracking system based on ZMQ-1 molecular sieve, applied to the method according to any one of claims 1 to 8, characterized in that: include: Raw material pretreatment unit, used for heating, desulfurization and removal of metal impurities of raw materials; A catalytic cracking unit, including a ZMQ-1 molecular sieve catalyst reactor, is used for cracking at a temperature of 450-550°C and a pressure of 0.1-0.3MPa; A product separation unit, used for condensing, gas-liquid separation and fraction recovery of cracking products; Catalyst regeneration unit is used to remove coke on the catalyst surface and regulate the acid center.

10. A high-efficiency catalytic cracking system based on ZMQ-1 molecular sieve according to claim 9, characterized in that: The product separation unit comprises: A condensation device for condensing and separating light olefins in the cracked gas; Gas-liquid separation unit for separating light aromatics and gasoline fractions; The circulating reflux device is used to return the incompletely cracked heavy oil products to the catalytic cracking unit for secondary cracking treatment.

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