Combined process method for improving vacuum residue catalytic cracking product yield

Abstract

The invention provides a combined process method for improving the yield of vacuum residue catalytic cracking products, which comprises the following steps: determining the asphaltene dispersion coefficient d of vacuum residue according to a formula (1), where w asphaltene, w colloid and w aromatics respectively represent the mass fractions of asphaltene, colloid and aromatics in vacuum residue; and carrying out modification and catalytic cracking reaction on the vacuum residue. According to the combined process method, the asphaltene dispersion coefficient d is ingeniously designed, and d is smaller than or equal to 0.5 and dgt; the vacuum residue of which the content is 0.5 is modified by adopting different modification methods, and then catalytic cracking reaction is performed under different conditions, so that the density of a catalyst in a reactor is improved, oil-agent contact in the reactor is improved, the contact instantaneous effective agent-oil ratio can be improved, the catalytic cracking reaction ratio can be remarkably improved, thermal cracking and condensation coke generation reactions are reduced, and the catalytic cracking efficiency is improved. Conversion of inferior heavy oil is promoted, meanwhile, the coke yield is remarkably reduced, and the yield of high-value products is increased.

Description

Technical Field

[0001] This invention relates to the field of catalytic cracking technology, specifically to a combined process method for improving the yield of vacuum residue catalytic cracking products. Background Technology

[0002] The most significant challenge in processing and utilizing heavy crude oil is the lightening of vacuum residue. Vacuum residue accounts for 40% to 50% of total crude oil. Due to its high density, high residual carbon, high metal content, and high sulfur and nitrogen content, vacuum residue is very difficult to process. Clean, efficient, and economically feasible vacuum residue processing technology has become one of the key challenges that the refining industry continues to tackle.

[0003] Since the 1990s, catalytic cracking (FCC) technology has played an increasingly important role in residue processing. Globally, FCC units blend residue with 25% to 75% of their output, and residue FCC conversion capacity accounts for over 25% of the world's total FCC production capacity. Heavy oil FCC units are the most important production facilities for heavy oil light processing in my country, currently processing approximately 47% of residue. Conventional FCC feedstocks are generally relatively high-quality residue with a carbon residue mass fraction of less than 6% and a nickel and vanadium mass fraction of less than 35 μg / g. Large quantities of high-sulfur, high-carbon residue, and high-metal content residue must undergo pretreatment before entering FCC units. This is because vacuum residue is a colloidal dispersion system with a supramolecular stable structure, composed of asphaltenes and heavy gums, which generally exists as molecular aggregates in crude oil or residue. In FCC units, the dispersed phase in the residue oil system cannot be fully atomized and dispersed, but preferentially adsorbs onto the catalyst surface, directly leading to a significant increase in coking. The accompanying metal deposition also accelerates catalyst deactivation, thus preventing the FCC unit from operating stably for extended periods. How to utilize the intervention of a dispersion medium to promote the depolymerization of asphaltenes to reduce coking in the catalytic cracking process and improve liquid yield has become a research focus.

[0004] Furthermore, vacuum residue is typically hydrotreated before being blended in catalytic cracking units. However, as the catalyst in the hydrotreating unit nears the end of its operation, the demetallization and decarbonization effects decrease. During catalyst replacement in the hydrotreating unit, the upgrading of vacuum residue becomes a limiting factor for its entry into catalytic cracking. Improving the colloidal dispersibility of vacuum residue and reducing its carbon residue content through simple and effective methods to decrease the coke yield in catalytic cracking has become a crucial technical requirement for refineries.

[0005] Supercritical water, with a critical temperature of 374.2℃ and a critical pressure of 22.12 MPa, possesses unique physicochemical properties, making it a preferred solvent that is inexpensive, readily available, and environmentally friendly. It is widely used in research on heavy oil reforming. Subcritical water typically refers to near-supercritical water with temperatures above 300℃ and pressures above 12 MPa, operating under relatively lower conditions. CN101558136A discloses a method for reforming heavy oil using supercritical water. This method allows for the continuous reforming of heavy oil into a light oil with low density, low viscosity, and low carbon residue using a tubular reactor through three or more processes: mixing, reforming, and separation. While this method can reform heavy oil, it does not address the adaptability of feedstocks, the degree of product reforming, or the processing and utilization of the reformed product.

[0006] CN106987265A discloses a method for reducing the viscosity of heavy oil based on supercritical water. This method involves mixing heavy oil with supercritical water and then transferring the thermal cracking of the heavy oil to supercritical water within a pseudo-homogeneous structure, thereby achieving viscosity reduction of the heavy oil at a relatively low temperature and in a short time. However, this method is an intermittent process and does not address the adaptability of feedstocks, the degree of product modification, or how the modified product is processed and utilized.

[0007] Although SCW has good dissolving power, its dissolving power for different components such as aromatics, gums, and asphaltenes varies significantly under the same conditions. While saturated components may dissolve completely under the same hydrothermal conditions, asphaltenes often only partially dissolve. Therefore, SCW exhibits significantly different dissolving and dispersing abilities for vacuum residue with different four-component compositions. Based on the colloidal solution theory of surfactants, asphaltenes and gums, which can form supramolecular structures, are considered surfactants. When their concentration is low, the micelles formed by the dispersed phase are spherical; when the concentration of asphaltenes and gums is high, the micelles formed by the dispersed phase are asymmetrical or layered. As the vacuum residue fraction becomes heavier, the supramolecular structures formed by asphaltenes and gums become larger. (Heavy Oil Chemistry, Liang Wenjie, 2000.8).

[0008] Improving the asphaltenes dispersibility of vacuum residue to increase the yield of high-value catalytic cracking products is a pressing technical problem that needs to be solved. Summary of the Invention

[0009] To address the above problems, this invention provides a combined process method for improving the yield of vacuum residue catalytic cracking products.

[0010] This invention provides a combined process method for improving the yield of vacuum residue catalytic cracking products, comprising:

[0011] S1. Determine the asphaltene dispersion coefficient d of vacuum residue according to formula (1).

[0012]

[0013] Among them, w 沥青质 w 胶质 w 芳香分 These represent the mass fractions of asphaltenes, resins, and aromatics in vacuum residue, respectively.

[0014] S2. The vacuum residue is subjected to upgrading and catalytic cracking reactions, wherein,

[0015] When d≤0.5, vacuum residue is subjected to the following upgrading and catalytic cracking reactions:

[0016] (S21) The vacuum residue is preheated with water and then fed into the reforming reactor to carry out the first hydrothermal reforming reaction under subcritical water conditions.

[0017] (S22) The water vapor is separated from the product of the first hydrothermal reforming reaction in a separator. The resulting first reformed oil is mixed with an optional catalytic cracking feedstock and then fed into a catalyst with a density of 50–80 kg / m³. 3 In a heavy oil reactor, a catalytic cracking reaction is carried out in the presence of a catalytic cracking catalyst to obtain reaction oil and gas and coking catalyst. The reaction oil and gas are separated to obtain the product.

[0018] When d > 0.5, the vacuum residue is subjected to the following upgrading and catalytic cracking reactions:

[0019] (T21) The vacuum residue is pre-dissolved in heavy circulation oil, then preheated with water and enters the reforming reactor to carry out the second hydrothermal reforming reaction under supercritical water conditions.

[0020] (T22) The second hydrothermal reforming reaction products are separated into heavy cycle oil, water, and second reformed oil in a separator; the second reformed oil is then mixed with optional catalytic cracking feedstock and fed into a catalyst with a density of 85–120 kg / m³. 3 In the heavy oil reactor, a catalytic cracking reaction is carried out in the presence of a catalytic cracking catalyst to obtain reaction oil and gas and coking catalyst. The reaction oil and gas are separated to obtain products and heavy cycle oil, and the obtained heavy cycle oil is used as a dispersion solvent.

[0021] And S3. The coking catalyst from steps (S22) and (T22) is recycled after being regenerated in a regenerator with low oxygen content.

[0022] Optionally, the vacuum residue oil has a density greater than 950 kg / m³ at 20°C. 3 The residual carbon content is not less than 10%, and the total mass fraction of resin and asphalt is greater than 20%.

[0023] Optionally, the subcritical conditions for water in step (S21) include:

[0024] The reaction temperature is 300–370℃, the reaction pressure is 10–20MPa, the reaction time is 3–10min, and the water-oil mass ratio is 1–4.

[0025] Preferably, the reaction temperature is 300–350°C, the reaction pressure is 12–18 MPa, the reaction time is 3–8 min, and the water-to-oil mass ratio is 1–2.

[0026] Optionally, in step (T21), before preheating with water, the vacuum residue and heavy circulation oil are preheated at a temperature of 250–350°C, preferably 250–300°C.

[0027] The heavy cycle oil mentioned in step (T21) has a distillation range of 250-300°C, wherein the mass fraction of bicyclic aromatics is 50%-80%, and the mass fraction of tricyclic and higher aromatics is less than 10%.

[0028] The mass ratio of the heavy circulating oil and the vacuum residue in step (T21) is (0.01~0.2):1.

[0029] Optionally, the supercritical conditions for water in step (T21) include:

[0030] The reaction temperature is 380–420℃, the reaction pressure is 22.5–30 MPa, the reaction time is 1–3 min, and the water-oil mass ratio is 3–5.

[0031] Optionally, in steps (S22) and (T22), the conditions of the separator each include: a temperature of 250–300°C and a pressure of 0.1–0.3 MPa;

[0032] The water mass fraction in the first modified oil and the second modified oil is 0.1% to 0.3% respectively.

[0033] Optionally, in steps (S22) and (T22), the catalytic cracking feedstock is selected from hydrotreated wax oil, hydrotreated residue oil, vacuum wax oil, atmospheric residue oil, coking wax oil, deasphalted oil, and feedstock oil.

[0034] In step (S22), the blending mass ratio of the first modified oil is 55-100%, based on the total mass of the first modified oil and the catalytic cracking feedstock.

[0035] In step (T22), the blending mass ratio of the second modified oil is 20-50%, based on the total mass of the second modified oil and the catalytic cracking feedstock.

[0036] Optionally, in steps (S22) and (T22), each of the heavy oil reactors is a combination of one or more selected from riser reactors, fluidized bed reactors, and upward conveying line reactors, or a combination of multiple reactors of the same type, including series and / or parallel connections; the riser reactor is a riser of equal diameter and / or a riser of variable diameter, and the fluidized bed reactor is selected from one or more selected from equal or variable diameter fast bed reactors, conveying bed reactors, and dense phase fluidized bed reactors;

[0037] The conditions for the catalytic cracking reaction in steps (S22) and (T22) each include:

[0038] The reaction temperature is 500-560℃, the reaction time is 1-20 seconds, the agent-to-oil weight ratio is (5-50):1, the water-to-oil weight ratio is (0.05-0.20):1, and the gas linear velocity is 0.5-3.0 m / s.

[0039] Optionally, the conditions for regenerating the coking catalyst obtained from steps (S22) and (T22) in the regenerator each include:

[0040] The regeneration temperature is 600–680℃, the apparent linear velocity of the fluidized bed gas is 0.1–3.0 m / s, the average residence time of the catalyst is 0.1–2.0 min, and the CO volume content in the regenerated flue gas is >1.0%.

[0041] Optionally, the catalytic cracking catalysts described in steps (S22) and (T22) are each independently:

[0042] It contains 15-65 wt% natural minerals, 10-30 wt% oxides, and 25-75 wt% Y-type molecular sieves and β-type molecular sieves; the weight ratio of Y-type molecular sieves and β-type molecular sieves is 1:4 to 4:0.1, and the Y-type molecular sieve is at least one of rare earth-containing DASY molecular sieves and REY molecular sieves;

[0043] Total specific surface area greater than 260m² 2 / g, the proportion of mesopore volume to total pore volume is 20% to 60%.

[0044] Beneficial effects:

[0045] This invention's combined process method ingeniously designs the asphaltene dispersion coefficient d, and uses different reforming methods to reform vacuum residue oil with d≤0.5 and d>0.5 respectively. Then, catalytic cracking reaction is carried out under different conditions to increase the catalyst density in the reactor and improve the oil-agent contact in the reactor. This can increase the effective agent-oil ratio at the moment of contact, significantly increase the proportion of catalytic cracking reaction, and reduce thermal cracking and condensation coking reactions. This achieves the goal of promoting the conversion of inferior heavy oil while significantly reducing coke yield and increasing the yield of high-value products. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of one embodiment of the combined process method of the present invention for improving the yield of vacuum residue catalytic cracking products, which is suitable for operation when the asphaltene dispersion coefficient d≤0.5;

[0047] Figure 2 This is a schematic diagram of one embodiment of the combined process method of the present invention for improving the yield of vacuum residue catalytic cracking products, which is suitable for operation when the asphaltene dispersion coefficient d>0.5;

[0048] Explanation of reference numerals in the attached figures

[0049] 1-Heavy oil reactor 2-Stripper 3-Settler

[0050] 4-Regenerator 5-Cyclone Separator 6-Gas Collection Chamber

[0051] 7-Regenerator line; 8-First slide valve; 9-Regenerator line

[0052] 10-Second slide valve; 11-Pre-lift medium; 12-Atomizing medium pipeline

[0053] 13-Catalytic cracking feed line 14-Stripping medium line

[0054] 15 - Reaction oil and gas pipeline; 16 - Regeneration medium pipeline; 17 - Regeneration flue gas pipeline

[0055] 18-Reforming reactor; 19-Separator; 20-Premixer

[0056] 21-Water vapor 22-Pressure relief residue pipeline 23-Light gas

[0057] 24 - Conventional catalytic cracking feedstock pipeline; 25 - Disperser; 26 - Heavy circulation oil pipeline

[0058] 27-Oil-water separator 28-Water Detailed Implementation

[0059] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. Through these descriptions, the features and advantages of the present application will become clearer and more apparent.

[0060] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0061] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0062] The inventors of this application have discovered that the compositional ratio of components in the colloidal structure of vacuum residue reflects the aromatic gradient of the dispersion medium and its ability to peptize asphaltenes, determining the colloidal state, the dispersion ability of initial asphaltenes, and the supramolecular structural hierarchy. Therefore, the overall colloidal structure of vacuum residue can be redefined based on its component composition. Based on its component mass composition, the asphaltenes dispersion coefficient is defined as follows: The colloidal structure of residual oil can be distinguished based on the asphaltene dispersion coefficient. The upgrading effect varies significantly for residual oils with different colloidal structures, resulting in marked differences in upgrading methods, conditions, utilization of upgraded products, and process design. Based on the above research, the following inventive idea is proposed.

[0063] This invention provides a combined process method for improving the yield of vacuum residue catalytic cracking products, comprising:

[0064] S1. Determine the asphaltene dispersion coefficient d of vacuum residue according to formula (1).

[0065]

[0066] Among them, w 沥青质 w 胶质 w 芳香分 These represent the mass fractions of asphaltenes, resins, and aromatics in vacuum residue, respectively.

[0067] S2. The vacuum residue is subjected to upgrading and catalytic cracking reactions, wherein,

[0068] When d≤0.5, vacuum residue is subjected to the following upgrading and catalytic cracking reactions:

[0069] (S21) The vacuum residue is preheated with water and then fed into the reforming reactor to carry out the first hydrothermal reforming reaction under subcritical water conditions.

[0070] (S22) The water vapor is separated from the product of the first hydrothermal reforming reaction in a separator. The resulting first reformed oil is mixed with an optional catalytic cracking feedstock and then fed into a catalyst with a density of 50–80 kg / m³. 3 In a heavy oil reactor, a catalytic cracking reaction is carried out in the presence of a catalytic cracking catalyst to obtain reaction oil and gas and coking catalyst. The reaction oil and gas are separated to obtain the product.

[0071] When d > 0.5, the vacuum residue is subjected to the following upgrading and catalytic cracking reactions:

[0072] (T21) The vacuum residue is pre-dissolved in heavy circulation oil, then preheated with water and enters the reforming reactor to carry out the second hydrothermal reforming reaction under supercritical water conditions.

[0073] (T22) The second hydrothermal reforming reaction products are separated into heavy cycle oil, water, and second reformed oil in a separator; the second reformed oil is then mixed with optional catalytic cracking feedstock and fed into a catalyst with a density of 85–120 kg / m³. 3 In the heavy oil reactor, a catalytic cracking reaction is carried out in the presence of a catalytic cracking catalyst to obtain reaction oil and gas and coking catalyst. The reaction oil and gas are separated to obtain products and heavy cycle oil, and the obtained heavy cycle oil is used as a dispersion solvent.

[0074] And S3. The coking catalyst from steps (S22) and (T22) is recycled after being regenerated in a regenerator with low oxygen content.

[0075] Specifically, in step (S21), the vacuum residue and water can be preheated separately before entering the reforming reactor. The preheating temperature for both vacuum residue and water can be 250–350°C. The reaction oil-gas separation in steps (S22) and (T22) can be carried out in the subsequent fractionation system. The catalyst density in steps (S22) and (T22) can represent the catalyst density per unit volume. The water vapor separated in step (S22), the heavy cycle oil separated in step (T22), and the water can be recycled. The statement in steps (S22) and (T22) that the reformed oil is mixed with optional catalytic cracking feedstock before entering the heavy oil reactor indicates that the reformed oil can be used alone as feedstock in the heavy oil reactor, in which case no other catalytic cracking feedstock is introduced, or the reformed oil is mixed with a certain amount of other catalytic cracking feedstock before entering the heavy oil reactor.

[0076] Through years of research and experimentation, the inventors of this application unexpectedly discovered that, based on the asphaltene dispersion coefficient d of the components in vacuum residue as described above, different colloidal structures can be defined for vacuum residue. When d ≤ 0.5, the colloidal structure of vacuum residue is in a sol state, and when d > 0.5, the colloidal structure of vacuum residue is in a gel state. Vacuum residue with different colloidal structures can undergo hydrothermal reforming under suitable conditions. The reformed products can then undergo catalytic cracking under the reaction conditions of contact with corresponding fortifying agents. This can effectively improve reforming efficiency, significantly increase the proportion of catalytic cracking reaction, promote the conversion of inferior heavy oil, significantly reduce coke yield, and increase the yield of valuable products. In particular, the asphalt dispersion coefficient d is cleverly defined using the above formula (1). When d ≤ 0.5, hydrothermal reforming is carried out under subcritical water conditions in step (S21), followed by catalytic cracking under the conditions of step (S22). When d > 0.5, hydrothermal reforming is carried out under supercritical water conditions in step (T21), followed by catalytic cracking under the conditions of step (T22). The conversion rate of vacuum residue is significantly improved, and the yield of high-value products such as liquefied petroleum gas, gasoline and diesel is greatly improved.

[0077] In one embodiment of the combined process method described above in this invention, the vacuum residue oil has a density greater than 950 kg / m³ at 20°C. 3 The residual carbon content is not less than 10%, and the total mass fraction of resin and asphalt is greater than 20%.

[0078] In this invention, the aforementioned vacuum residue can be a vacuum residue fraction obtained under conventional vacuum distillation conditions well known in the art. When the vacuum residue under the above conditions is modified and catalytically cracked according to the combined process method of this invention, the vacuum residue can be better converted into high-value products such as liquefied petroleum gas, gasoline and diesel, while the yield of heavy oil and coke is significantly reduced.

[0079] In another embodiment of the combined process method described above, the subcritical conditions for water in step (S21) include:

[0080] The reaction temperature is 300–370℃, the reaction pressure is 10–20MPa, the reaction time is 3–10min, and the water-oil mass ratio is 1–4.

[0081] Preferably, the reaction temperature is 300–350°C, the reaction pressure is 12–18 MPa, the reaction time is 3–8 min, and the water-to-oil mass ratio is 1–2.

[0082] It should be noted that for vacuum residue with d≤0.5, by controlling the subcritical conditions of water in step (S21) as described above, the first modified oil obtained can complete the catalytic cracking reaction with a higher conversion rate and obtain high yields of liquefied petroleum gas, gasoline and diesel. In particular, when the subcritical conditions of water are optimally controlled as described above, the yield of high-value products can be further improved, and the yields of heavy oil and coke can be significantly reduced.

[0083] In one embodiment of the above-described combined process method of the present invention, in step (T21), before preheating with water, the vacuum residue and heavy circulation oil are preheated at a temperature of 250-350°C, preferably 250-300°C.

[0084] The heavy cycle oil mentioned in step (T21) has a distillation range of 250-300°C, wherein the mass fraction of bicyclic aromatics is 50%-80%, and the mass fraction of tricyclic and higher aromatics is less than 10%.

[0085] The mass ratio of the heavy circulating oil and the vacuum residue in step (T21) is (0.01~0.2):1.

[0086] It should be noted that for vacuum residue with d>0.5, heavy cycle oil with the above-mentioned distillation range and composition is selected, and vacuum residue and heavy cycle oil are mixed in the above-mentioned mass ratio and preheated at the above-mentioned temperature. Then, after preheating with water, a reforming reaction is carried out. The reformed products obtained in this way can be better converted into high-value products such as liquefied petroleum gas, gasoline and diesel through subsequent catalytic cracking steps.

[0087] In another embodiment of the combined process method described above, the supercritical conditions for water in step (T21) include:

[0088] The reaction temperature is 380–420℃, the reaction pressure is 22.5–30 MPa, the reaction time is 1–3 min, and the water-oil mass ratio is 3–5.

[0089] It should be noted that for vacuum residue with d>0.5, by controlling the supercritical conditions of water in step (T21) as described above, the second modified oil obtained can complete the catalytic cracking reaction with a higher conversion rate and obtain high yields of liquefied petroleum gas, gasoline and diesel, while significantly reducing the yields of heavy oil and coke.

[0090] In one embodiment of the above-described combined process method of the present invention, in steps (S22) and (T22), the conditions of the separator each include: a temperature of 250-300°C and a pressure of 0.1-0.3 MPa.

[0091] The water mass fraction in the first modified oil and the second modified oil is 0.1% to 0.3% respectively.

[0092] By controlling the separation conditions in steps (S22) and (T22) as described above, and controlling the water content of the two types of modified oils as described above, the modified oils are subjected to catalytic cracking reactions in steps (S22) and (T22) respectively. This can reduce the generation of heavy oil and coke while obtaining a high yield of high-value products.

[0093] In one embodiment of the above-described combined process method of the present invention, in steps (S22) and (T22), the catalytic cracking feedstock is selected from hydrogenated wax oil, hydrogenated residue oil, vacuum wax oil, atmospheric residue oil, coking wax oil, deasphalted oil, and feedstock oil.

[0094] In step (S22), the blending mass ratio of the first modified oil is 55-100%, based on the total mass of the first modified oil and the catalytic cracking feedstock.

[0095] In step (T22), the blending mass ratio of the second modified oil is 20-50%, based on the total mass of the second modified oil and the catalytic cracking feedstock.

[0096] Specifically, the feedstock oil used as a feedstock for catalytic cracking can be any processed feedstock oil suitable for direct use as a feedstock for catalytic cracking. The blending mass ratio of the first modified oil represents the proportion of the first modified oil in the total mass of the first modified oil and the catalytic cracking feedstock, and the blending mass ratio of the second modified oil represents the proportion of the second modified oil in the total mass of the second modified oil and the catalytic cracking feedstock.

[0097] Based on the properties and reactivity of vacuum residue, its viscosity, asphaltene dispersibility, carbon residue, and molecular weight are significantly improved after modification. However, using it alone as a feedstock for catalytic cracking may affect the long-term operation of the unit, especially the coking situation and catalyst activity. Metal deposition on the catalyst can lead to extremely high catalyst consumption. Therefore, in practice, it is preferable to blend it with conventional catalytic cracking feedstock. Moreover, the performance and product distribution of vacuum residue are significantly improved, and the blending ratio can be greatly increased in actual processing. Conventional catalytic cracking feedstocks generally have a carbon residue mass fraction of less than 6% and a total mass fraction of nickel and vanadium of less than 30 μg / g. When vacuum residue is blended, controlling the blending ratio as described above in steps (S22) and (T22) allows the mixture formed by the modified oil and catalytic cracking feedstock to complete the catalytic cracking reaction with a high conversion rate. The yields of high-value products such as liquefied petroleum gas, gasoline, and diesel are high, while the yields of heavy oil and coke are significantly reduced.

[0098] In one embodiment of the combined process method described above in this invention, in steps (S22) and (T22), each of the heavy oil reactors is a combination of one or more selected from riser reactors, fluidized bed reactors, and upward conveying line reactors, or a combination of multiple reactors of the same type, wherein the combination method includes series and / or parallel connection; the riser reactor is a riser of equal diameter and / or a riser of variable diameter, and the fluidized bed reactor is selected from one or more selected from equal diameter or variable diameter fast bed reactors, conveying bed reactors, and dense phase fluidized bed reactors;

[0099] The conditions for the catalytic cracking reaction in steps (S22) and (T22) each include:

[0100] The reaction temperature is 500-560℃, the reaction time is 1-20 seconds, the agent-to-oil weight ratio is (5-50):1, the water-to-oil weight ratio is (0.05-0.20):1, and the gas linear velocity is 0.5-3.0 m / s.

[0101] It should be noted that vacuum residue has a high density, high carbon residue, and high metal content. Although its properties are significantly improved after reforming, it still requires more favorable reaction conditions for contact with the catalyst to increase the proportion of catalytic cracking, reduce thermal cracking and condensation coking reactions, and reduce the impact of metal deposition on the reaction. However, in conventional catalytic cracking reactors, the catalyst is mainly transported in a dilute phase, making it difficult to meet these requirements. Furthermore, vacuum residue has a large molecular weight and large molecular dynamic diameter, resulting in poor contact and diffusion with the catalyst, poor accessibility to the catalyst's active sites, and unsatisfactory conversion and product selectivity. By selecting a heavy oil reactor as described above and controlling the catalytic cracking reaction conditions as described above, especially controlling the catalyst density to 50–80 kg / m³ in steps (S22) and (T22), the desired catalytic cracking solution can be achieved. 3 85~120kg / m 3 This can further improve the conversion rate of vacuum residue, thereby increasing the yield of high-value products such as liquefied petroleum gas, gasoline, and diesel.

[0102] In one embodiment of the combined process method of the present invention, the conditions for regenerating the coking catalyst obtained from steps (S22) and (T22) in the regenerator each include:

[0103] The regeneration temperature is 600–680℃, the apparent linear velocity of the fluidized bed gas is 0.1–3.0 m / s, the average residence time of the catalyst is 0.1–2.0 min, and the CO volume content in the regenerated flue gas is >1.0%.

[0104] It should be noted that by controlling the catalyst regeneration conditions as described above, the resulting regenerated catalyst, when playing a catalytic role in steps (S22) and (T22), is conducive to better converting the hydrothermally reformed oil into high-value products such as liquefied petroleum gas, gasoline, and diesel, while reducing the generation of heavy oil and coke.

[0105] In one embodiment of the combined process method of the present invention, the catalytic cracking catalysts described in steps (S22) and (T22) are each independent:

[0106] It contains 15-65 wt% natural minerals, 10-30 wt% oxides, and 25-75 wt% Y-type molecular sieves and β-type molecular sieves; the weight ratio of Y-type molecular sieves and β-type molecular sieves is 1:4 to 4:0.1, and the Y-type molecular sieve is at least one of rare earth-containing DASY molecular sieves and REY molecular sieves;

[0107] Total specific surface area greater than 260m² 2 / g, the proportion of mesopore volume to total pore volume is 20% to 60%.

[0108] Vacuum residue has a high metal content, which continuously deposits on the catalyst surface during catalytic cracking. In particular, the vanadium-formed V₂O₅ has a melting point lower than the catalyst's regeneration temperature (approximately 700°C), flowing across the catalyst surface as a highly fluid substance and entering the zeolite and its acidic centers along the catalyst's pores. It reacts with sodium in the catalyst to form nNa₂O·V₂O₅, which has an even lower melting point, damaging the zeolite structure and reducing the catalyst's thermal stability. Furthermore, vacuum residue has a large molecular diameter and high content of cycloalkanes and aromatic hydrocarbons. To enhance contact with the catalyst and diffusion within the pores, it is necessary to increase the catalyst's specific surface area and pore diameter, while simultaneously enhancing its performance in promoting cycloalkanes to open rings. By controlling the composition, total specific surface area, and mesoporous volume ratio of the catalytic cracking catalyst as described above, high conversion rates and high yields of high-value products can be achieved.

[0109] In summary, this invention utilizes hydrothermal conditions for reforming, achieving similar reforming effects in a shorter time compared to viscosity-reducing cracking, thus effectively improving processing efficiency. Simultaneously, under the selected conditions, virtually no coke or cracking gas is generated, simplifying the process and facilitating implementation. Through hydrothermal reforming, the optimized reactor increases catalyst density and improves oil-catalyst contact, thereby increasing the instantaneous effective catalyst-to-oil ratio, significantly increasing the proportion of catalytic cracking reactions, and reducing thermal cracking and condensation coking reactions. This achieves the goal of promoting the conversion of inferior heavy oil while significantly reducing coke yield and increasing the yield of high-value products.

[0110] When d≤0.5, the reforming and catalytic cracking of vacuum residue can be carried out as follows: Figure 1 The process is carried out in the system shown. When d > 0.5, the upgrading and catalytic cracking reactions of vacuum residue can be performed as follows: Figure 2 The process is carried out in the system shown. The vacuum residue from the vacuum residue pipeline 22 enters the disperser 25 for dispersion and depolymerization under the dissolution and dispersion of the heavy circulation oil from the heavy circulation oil pipeline 26. The preheated mixed oil and water vapor 21 enter the reforming reactor 18 for hydrothermal reforming. The reforming product enters the separator 19 to separate the light gas and obtain the reformed oil. The light gas 23 enters the oil-water separator 27 to separate the heavy circulation oil and water 28, which can be recycled.

[0111] The modified oil and conventional catalytic cracking feedstock (optional) from conventional catalytic cracking feedstock line 24 are uniformly mixed in premixer 20, and then used as catalytic feedstock to enter heavy oil reactor 1 via catalytic cracking feedstock line 13. High-temperature regenerated catalyst from regenerator line 9 moves upward along the riser under the lifting action of pre-lifting medium 11. Catalytic feedstock from catalytic cracking feedstock line 13 is atomized and dispersed by atomizing medium from atomizing medium line 12, and then reacts with the high-temperature catalyst. The resulting reaction oil gas and coked catalyst are separated in settling tank 3 by cyclone separator 5. The separated reaction oil gas enters gas collection chamber 6 and then goes to subsequent separation unit via reaction oil gas line 15 to separate dry gas, liquefied petroleum gas, gasoline, light cycle oil, heavy cycle oil, and other products. The heavy cycle oil can be used as a dispersion solvent to mix with vacuum residue and then enter disperser 25 for recycling. The coking catalyst is stripped in the stripper 2 via the stripping medium from the stripping medium pipeline 14 and then enters the regenerator 4 via the regenerator pipeline 7 (which is equipped with a first slide valve 8). It comes into contact with the regenerating medium from the regenerating medium pipeline 16 to undergo incomplete coking regeneration (oxygen-deficient regeneration). The generated regenerated flue gas goes to the subsequent unit via the regenerated flue gas pipeline 17. The high-temperature regenerated catalyst returns to the heavy oil reactor 1 via the regenerating medium pipeline 9 (which is equipped with a second slide valve 10).

[0112] When d≤0.5, the reforming and catalytic cracking of vacuum residue can be carried out. Figure 1 Performed in the system shown. Figure 1 The operation process and Figure 2 similar.

[0113] The present invention will be further described in detail below through examples, but these examples are not intended to limit the invention. In the following examples, unless otherwise specified, the experimental instruments and raw materials involved are all commercially available products.

[0114] The properties of the heavy oil feedstock used in the examples are shown in Table 1. The commercial brand of the cracking catalyst used is CDOS, produced by Qilu Catalyst Plant of China Petroleum & Chemical Corporation Catalyst Branch. The properties of the catalyst are shown in Table 2.

[0115] In Table 1, the asphaltene dispersion coefficient d for vacuum residue A and vacuum residue B is calculated according to the following formula (1):

[0116]

[0117] Table 1 Properties of Heavy Oil Feedstock

[0118] project Vacuum residue A Vacuum residue B Hydrogenated wax oil <![CDATA[Density at 20 °C, kg / m 3 > 1008.0 1125.0 897.1 Carbon residue,% 17.6 29.8 0.21 Composed of four components, % Saturated hydrocarbons 17.5 45.60 77.0 Aromatics 52.50 24.70 19.8 gelatinous 25.20 14.20 3.2 Asphalt 5.00 15.50 <0.11 Asphalt dispersion coefficient d 0.11 1.31 /

[0119] Table 2 Catalyst Properties

[0120] Catalyst number CDOS Main chemical composition (%) <![CDATA[Al2O3]]> 53.50 <![CDATA[SiO2]]> 39.20 <![CDATA[Na2O]]> 0.431 <![CDATA[Heap ratio, kg / m 3 > 875 Pore ​​volume, mL / g 0.50 <![CDATA[Specific surface area, m 2 / g]]> 280 Average particle size, μm 66 active,% 64

[0121] Example 1

[0122] According to the embodiments Figure 1 The system process was tested on a medium-sized unit. Vacuum residue A was preheated to 280°C, water was preheated to 280°C, and the mixture was reformed in a reforming reactor at a reaction temperature of 325°C, a water-to-oil mass ratio of 2, a reaction pressure of 15 MPa, and a reaction time of 4 min. The reformed product was subjected to water vapor separation at a temperature of 250°C and a pressure of 0.2 MPa, and the resulting reformed oil (with a water mass fraction of 0.13%) entered a catalytic reactor. The reactor was then tested at a reaction temperature of 520°C, a reaction time of 3 seconds, a catalyst-to-oil weight ratio of 20, a water-to-oil weight ratio of 0.1, a gas linear velocity of 1.0 m / s, and a catalyst density of 65 kg / m³ per unit volume in the riser reactor. 3 The reaction occurs under certain conditions. The reacting oil and gas and the spent catalyst are separated in a settling tank. The reacting oil and gas are then separated into products in a subsequent separation unit. The spent catalyst is sent to a regenerator for oxygen-deficient regeneration under conditions of a regeneration temperature of 650℃, a gas linear velocity of 2.0m / s, and a residence time of 0.3min. The CO volume content in the regenerated flue gas is 1.2%.

[0123] Detailed operating conditions and test results are shown in Table 3.

[0124] Comparative Example 1-1

[0125] The reaction and regeneration units of the experimental apparatus were the same as in Example 1, except for the modification unit. The reaction and regeneration conditions were the same as in Example 1. Detailed operating conditions and experimental results are shown in Table 3.

[0126] Comparative Examples 1-2

[0127] The reaction and regeneration units of the experimental setup were the same as in Example 1. The modified oil of vacuum residue A, heat-treated at 350°C for 40 min, was used as the catalyst feedstock. The reaction and regeneration conditions were the same as in Example 1. Detailed operating conditions and experimental results are shown in Table 3.

[0128] Table 3

[0129]

[0130]

[0131] As can be seen, compared with untreated and heat-treated vacuum residue A, the conversion rate of upgraded vacuum residue A can be increased by 6.70 percentage points and 5.54 percentage points, respectively. The product distribution is mainly higher-value liquefied petroleum gas (LPG) and gasoline, while the yields of heavy oil and coke are significantly reduced. The total yields of LPG, gasoline, and diesel from upgraded vacuum residue A can be increased by 6.39 percentage points and 4.54 percentage points, respectively.

[0132] Furthermore, the product distribution of vacuum residue A after hydrothermal modification for 4 minutes was significantly better than that after heat treatment for 40 minutes, and the modification efficiency was significantly better than that after heat treatment.

[0133] Example 2

[0134] According to the embodiments Figure 2 The system process was tested on a medium-sized unit. Heavy circulating oil preheated to 280°C was dissolved with vacuum residue B at a ratio of 0.15:1. Water was preheated to 280°C. The mixture was then subjected to a reforming reaction in a reforming reactor at a reaction temperature of 400°C, a water-to-oil mass ratio of 3, a reaction pressure of 23 MPa, and a reaction time of 2 min. The reformed product was separated into light oil and gas (heavy circulating oil and water) at 280°C and 0.2 MPa. The resulting reformed oil (with a water mass fraction of 0.12%) was mixed with hydrotreated wax oil at a 30% ratio (30% being the percentage of reformed oil in the total feed) and fed into a fast fluidized bed reactor. The reactor was operated at a reaction temperature of 520°C, a reaction time of 3 seconds, a catalyst-to-oil weight ratio of 20, a water-to-oil weight ratio of 0.1, a gas linear velocity of 1.5 m / s, and a catalyst density of 110 kg / m³ per unit volume. 3 The reaction occurs under certain conditions. The reaction oil and gas and the spent catalyst are separated in a settling tank. The reaction oil and gas are then separated in a subsequent separation unit to obtain the product and recycle oil (which is recycled as a dispersion solvent). The spent catalyst is sent to the regenerator for oxygen-deficient regeneration under the conditions of a regeneration temperature of 650℃, a gas linear velocity of 2.0m / s, and a residence time of 0.3min. The CO volume content in the regenerated flue gas is 1.2%.

[0135] The heavy cycle oil has a distillation range of 265–300℃, with a bicyclic aromatic hydrocarbon mass fraction of 72% and a tricyclic or higher aromatic hydrocarbon mass fraction of 6%.

[0136] Detailed operating conditions and test results are shown in Table 4.

[0137] Comparative Example 2-1

[0138] The reaction and regeneration units of the experimental apparatus were the same as in Example 2, except for the modification unit. Vacuum residue B and hydrotreated wax oil were mixed in the same proportion. The reaction and regeneration conditions were the same as in Example 2. Detailed operating conditions and experimental results are shown in Table 4.

[0139] Comparative Example 2-2

[0140] The reaction and regeneration units of the experimental apparatus were the same as in Example 2. The modified oil of vacuum residue B, heat-treated at 400°C for 40 min, was mixed with hydrotreated wax oil in the same proportion and used as the catalyst feedstock. The reaction and regeneration conditions were the same as in Example 2. Detailed operating conditions and experimental results are shown in Table 4.

[0141] Comparative Examples 2-3

[0142] The reaction unit and regeneration unit of the experimental apparatus are the same as those in Example 2, except that:

[0143] Vacuum residue B was reformed under subcritical water conditions. The reforming conditions were as follows:

[0144] The modification reaction was carried out at a reaction temperature of 320℃, a water-to-oil mass ratio of 3, a reaction pressure of 12MPa, and a reaction time of 2min.

[0145] Table 4

[0146] Comparative Example 2-1 Comparative Example 2-2 Comparative Examples 2-3 Example 2 Modification unit Reaction temperature / °C / 400 320 400 Reaction pressure / MPa / 2 12 23 Water-oil mass ratio / / 3 3 Reaction time / min / 40 2 2 Catalytic unit Reaction temperature / °C 520 520 520 520 Agent-to-oil ratio 20 20 20 20 Water-oil weight ratio 0.1 0.1 0.1 0.1 <![CDATA[Catalyst density / (kg / m 3 )]]> 110 110 110 110 Product distribution / % dry air 5.35 5.08 4.90 4.56 Liquefied gas 9.10 12.02 14.02 16.56 gasoline 24.47 28.42 29.17 32.24 diesel fuel 23.63 22.63 21.78 20.12 heavy oil 18.62 14.64 14.31 13.2 coke 18.83 17.21 15.82 13.32 Conversion rate / % 57.75 62.73 63.91 66.68 (Liquefied petroleum gas + gasoline + diesel) / % 57.20 63.07 64.97 68.92

[0147] As can be seen, compared with untreated, heat-treated, and subcritically reformed vacuum residue B, the conversion rate of supercritically reformed vacuum residue B can be increased by 8.93 percentage points, 3.95 percentage points, and 2.77 percentage points, respectively. The product distribution is mainly higher-value liquefied petroleum gas (LPG) and gasoline, while the yields of heavy oil and coke are significantly reduced. The total yields of LPG, gasoline, and diesel from supercritically reformed vacuum residue B can be increased by 11.72 percentage points, 5.85 percentage points, and 3.95 percentage points, respectively.

[0148] Furthermore, the product distribution of vacuum residue B after 2 minutes of hydrothermal modification was significantly better than that after 40 minutes of heat treatment, and the modification efficiency was significantly better than that after heat treatment.

[0149] In the description of this application, it should be noted that the terms "upper", "lower", "inner", "outer", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship in the working state of this application. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0150] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0151] The present application has been described above with reference to preferred embodiments; however, these embodiments are merely exemplary and illustrative. Various substitutions and modifications can be made to the present application based on these embodiments, all of which fall within the protection scope of the present application.

Claims

1. A combined process method for improving the yield of vacuum residue catalytic cracking products, characterized in that, include: S1. Determine the asphaltene dispersion coefficient d of vacuum residue according to formula (1). Among them, w 沥青质 w 胶质 w 芳香分 These represent the mass fractions of asphaltenes, resins, and aromatics in vacuum residue, respectively. S2. The vacuum residue is subjected to upgrading and catalytic cracking reactions, wherein, When d≤0.5, vacuum residue is subjected to the following upgrading and catalytic cracking reactions: (S21) The vacuum residue is preheated with water and then fed into the reforming reactor to carry out the first hydrothermal reforming reaction under subcritical water conditions. (S22) The water vapor is separated from the product of the first hydrothermal reforming reaction in a separator. The resulting first reformed oil is mixed with an optional catalytic cracking feedstock and then fed into a catalyst with a density of 50–80 kg / m³. 3 In a heavy oil reactor, a catalytic cracking reaction is carried out in the presence of a catalytic cracking catalyst to obtain reaction oil and gas and coking catalyst. The reaction oil and gas are separated to obtain the product. When d > 0.5, the vacuum residue is subjected to the following upgrading and catalytic cracking reactions: (T21) The vacuum residue is pre-dissolved in heavy circulation oil, then preheated with water and enters the reforming reactor to carry out the second hydrothermal reforming reaction under supercritical water conditions. (T22) The second hydrothermal reforming reaction products are separated into heavy cycle oil, water, and second reformed oil in a separator; the second reformed oil is then mixed with optional catalytic cracking feedstock and fed into a catalyst with a density of 85–120 kg / m³. 3 In the heavy oil reactor, a catalytic cracking reaction is carried out in the presence of a catalytic cracking catalyst to obtain reaction oil and gas and coking catalyst. The reaction oil and gas are separated to obtain products and heavy cycle oil, and the obtained heavy cycle oil is used as a dispersion solvent. And S3. The coking catalyst from steps (S22) and (T22) is recycled after being regenerated in a regenerator with low oxygen content.

2. The combined process method according to claim 1, characterized in that, The vacuum residue oil has a density greater than 950 kg / m³ at 20°C. 3 The residual carbon content is not less than 10%, and the total mass fraction of resin and asphalt is greater than 20%.

3. The combined process method according to claim 1, characterized in that, The subcritical conditions for water in step (S21) include: The reaction temperature is 300–370℃, the reaction pressure is 10–20MPa, the reaction time is 3–10min, and the water-oil mass ratio is 1–4. Preferably, the reaction temperature is 300–350°C, the reaction pressure is 12–18 MPa, the reaction time is 3–8 min, and the water-to-oil mass ratio is 1–2.

4. The combined process method according to claim 1, characterized in that, In step (T21), before preheating with water, the vacuum residue and heavy circulation oil are preheated at a temperature of 250-350°C, preferably 250-300°C. The heavy cycle oil mentioned in step (T21) has a distillation range of 250-300°C, wherein the mass fraction of bicyclic aromatics is 50%-80%, and the mass fraction of tricyclic and higher aromatics is less than 10%. The mass ratio of the heavy circulating oil and the vacuum residue in step (T21) is (0.01~0.2):

1.

5. The combined process method according to claim 1, characterized in that, The supercritical conditions for water in step (T21) include: The reaction temperature is 380–420℃, the reaction pressure is 22.5–30 MPa, the reaction time is 1–3 min, and the water-oil mass ratio is 3–5.

6. The combined process method according to claim 1, characterized in that, In steps (S22) and (T22), the conditions for the separator each include: a temperature of 250–300°C and a pressure of 0.1–0.3 MPa. The water mass fraction in the first modified oil and the second modified oil is 0.1% to 0.3% respectively.

7. The combined process method according to claim 1, characterized in that, In steps (S22) and (T22), the catalytic cracking feedstocks are each selected from hydrotreated wax oil, hydrotreated residue oil, vacuum wax oil, atmospheric residue oil, coking wax oil, deasphalted oil, and feedstock oil; In step (S22), the blending mass ratio of the first modified oil is 55-100%, based on the total mass of the first modified oil and the catalytic cracking feedstock. In step (T22), the blending mass ratio of the second modified oil is 20-50%, based on the total mass of the second modified oil and the catalytic cracking feedstock.

8. The combined process method according to claim 1, characterized in that, In steps (S22) and (T22), each of the heavy oil reactors is a combination of one or more selected from riser reactors, fluidized bed reactors, and upward conveying line reactors, or a combination of multiple reactors of the same type, with the combination method including series and / or parallel connection; the riser reactor is a riser of equal diameter and / or a riser of variable diameter, and the fluidized bed reactor is selected from one or more selected from equal diameter or variable diameter fast bed reactors, conveying bed reactors, and dense phase fluidized bed reactors; The conditions for the catalytic cracking reaction in steps (S22) and (T22) each include: The reaction temperature is 500-560℃, the reaction time is 1-20 seconds, the agent-to-oil weight ratio is (5-50):1, the water-to-oil weight ratio is (0.05-0.20):1, and the gas linear velocity is 0.5-3.0 m / s.

9. The combined process method according to claim 1, characterized in that, The conditions for regenerating the coked catalyst obtained from steps (S22) and (T22) in the regenerator each include: The regeneration temperature is 600–680℃, the apparent linear velocity of the fluidized bed gas is 0.1–3.0 m / s, the average residence time of the catalyst is 0.1–2.0 min, and the CO volume content in the regenerated flue gas is >1.0%.

10. The combined process method according to claim 1, characterized in that, The catalytic cracking catalysts described in steps (S22) and (T22) are each independent: It contains 15–65 wt% natural minerals, 10–30 wt% oxides, and 25–75 wt% Y-type and β-type molecular sieves; the weight ratio of Y-type and β-type molecular sieves is 1:4 to 4: 0.1, the Y-type molecular sieve is at least one of the rare earth-containing DASY molecular sieve and REY molecular sieve; Total specific surface area greater than 260m² 2 / g, the proportion of mesopore volume to total pore volume is 20% to 60%.

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