A method for processing residual oil

Abstract

This invention discloses a method for processing residual oil. The method includes sequentially subjecting the residual oil feedstock to alkali metal treatment and catalytic cracking, followed by separation to obtain catalytic cracking heavy distillate oil; the catalytic cracking heavy distillate oil is mixed with alkali metal and filtered through a catalytic cracking filtration unit, then mixed with the residual oil feedstock for alkali metal treatment. This method significantly improves the reaction efficiency of alkali metal treatment in residual oil, has low operational severity and low hydrogen consumption, and a long operating cycle. It can maximize the quality and yield of light oil products while reducing equipment operating costs.

Description

Technical Field

[0001] This invention relates to a method for processing residual oil, and more specifically to a method for processing residual oil using an alkali metal treatment-catalytic cracking combined process. Background Technology

[0002] Deep processing of heavy oil is a key area of ​​technological development in the refining industry, and it is of great significance for improving the depth of crude oil processing and increasing the yield of light oil. Catalytic cracking is one of the most important methods for lightening heavy oil, with advantages such as high conversion rate, high production flexibility, and low investment and operating costs. However, residue oil fractions are enriched with a large amount of non-ideal components such as sulfur, nitrogen, metals, and asphaltenes, which can easily cause deactivation of catalytic cracking catalysts and a reduction in oil quality. Therefore, it is necessary to combine catalytic cracking with other processes to process residue oil feedstocks, and to use other processes to pretreat the residue oil feedstocks to reduce the impurity content and lower the carbon residue value.

[0003] Currently, the most widely used pretreatment method for catalytic cracking feedstock is residue hydrotreating, i.e., a combined process of residue hydrotreating and catalytic cracking.

[0004] CN102876377A discloses a fixed-bed residue hydrotreating-catalytic cracking combined process. The feedstock, after passing through an upflow reactor, is mixed with catalytic cracking heavy fraction and then enters a downflow fixed-bed reactor. The liquid phase obtained after separation of the hydrotreating effluent undergoes catalytic cracking, and the resulting catalytic cracking heavy fraction is returned to the inlet of the downflow fixed-bed reactor. This invention increases the bed porosity by using an upflow reactor, which alleviates to some extent the problem of large pressure drop changes at the beginning and end of conventional fixed-bed reactors, thus helping to extend the operating cycle. However, the upflow reactor provides a relatively hydrogen-deficient atmosphere, which can lead to the slow formation of sediments or coke, affecting feedstock distribution and flow, and ultimately causing hot spots. Therefore, this invention cannot fundamentally solve the problems of poor adaptability to feedstocks and short operating cycles in fixed-bed residue hydrotreating technology.

[0005] CN102453547A discloses a combined process for heavy oil to lighten distillate. This method employs two fluidized bed reactors connected in series for the hydroconversion of heavy oil feedstock, with the hydrotreated product used as feedstock for a catalytic cracking unit. The fluidized bed reactors are sequentially loaded with a hydrodemetallization catalyst and a hydrodesulfurization catalyst. When the catalyst activity in one of the fluidized bed reactors significantly decreases, that reactor is removed from the combined process flow, and a standby reactor containing the same catalyst is switched on to continue the hydrotreating operation, ensuring continuous operation of the combined process. This method can save costs, simplify the operation process, and maximize the production of light distillate oil; it also ensures the continuity of the entire fluidized bed operating system, guaranteeing long-term operation of the unit. However, this method requires switching reactors online under high temperature and high pressure conditions, placing high demands on the performance of the high-pressure switching valve and the skills of the operators. Furthermore, fluidized bed residue hydrotreating, as a traditional hydrotreating technology, still suffers from drawbacks such as high reaction severity, high hydrogen consumption, and poor desulfurization selectivity.

[0006] CN101434867A discloses a combined process of slurry bed residue hydrotreating and catalytic cracking. Residue oil and catalytic cracking clarified oil are fed together into a slurry bed hydrotreating unit, where a hydrotreating reaction is carried out in the presence of hydrogen and a catalyst. The vacuum distillate obtained from the hydrotreating reaction enters the catalytic cracking unit, while the vacuum residue oil is recycled back to the slurry bed hydrotreating unit. The catalytic cracking clarified oil and heavy recycle oil can be wholly or partially fed into the slurry bed hydrotreating unit. Although the feedstock adaptability and operating cycle of slurry bed residue hydrotreating technology are superior to those of fixed bed residue hydrotreating technology, the tail oil from slurry bed residue hydrotreating is difficult to process, and this technology cannot fundamentally overcome the drawbacks of traditional hydrotreating technologies, such as high reaction severity, high hydrogen consumption, and poor desulfurization selectivity. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for processing residual oil. This method fully utilizes the characteristics of alkali metal treatment and catalytic cracking technologies, significantly improving the reaction efficiency of alkali metal treatment in residual oil. It features low operational severity, low hydrogen consumption, and a long operating cycle, maximizing the quality and yield of light oil products while reducing operating costs.

[0008] A method for processing residual oil, wherein the method employs a combined process of alkali metal treatment and catalytic cracking. The residual oil feedstock is sequentially treated with alkali metal and then catalytic cracking to obtain a catalytic cracking heavy distillate oil. The catalytic cracking heavy distillate oil is mixed with alkali metal and filtered through a catalytic cracking filtration device. The resulting material is then mixed with the residual oil feedstock for alkali metal treatment.

[0009] A specific method for processing residual oil, the method comprising the following steps:

[0010] (1) After the alkali metal and the heavy distillate oil from the catalytic cracking unit are mixed, they enter the filtration system of the catalytic cracking unit;

[0011] (2) The filtered material obtained in step (1) is mixed with the residual oil raw material and fed into the residual oil alkali metal treatment device for reaction;

[0012] (3) The material after the reaction in step (2) is separated into solid phase products and generated oil by solid-liquid separation;

[0013] (4) The generated oil obtained in step (3) enters the catalytic cracking unit and reacts in the presence of the catalytic cracking catalyst. The reaction products are separated to obtain dry gas, liquefied gas, gasoline, diesel and heavy distillate oil. The heavy distillate oil repeats the process of step (1).

[0014] In step (1) of the method of the present invention, the alkali metal includes one or more of lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs) and francium (Fr), preferably lithium (Li), sodium (Na) and potassium (K).

[0015] In step (1) of the method of the present invention, the heavy distillate oil of the catalytic cracking unit is a fraction with a temperature >230°C.

[0016] In step (1) of the method of the present invention, the alkali metal is liquefied by heating to a suitable temperature and then mixed with catalytic cracking heavy distillate oil in a mixer to obtain a liquid-phase alkali metal-liquid-phase heavy distillate oil mixture. The temperature is generally 100-280℃, preferably 180-250℃. The mixer includes various types of equipment that can achieve material mixing, such as SK type, SV type, SX type static mixer, jet mixer, and Venturi mixer.

[0017] In step (1) of the method of this invention, the filtration system of the catalytic cracking unit can adopt conventional catalytic cracking slurry filtration systems in the prior art, such as the Hypulse LSI filtration system developed by MOTT Corporation of the United States, the fully automatic slurry filter system developed by PALL Corporation of the United States, and the porous metal filtration technology developed by China University of Petroleum or Antai Technology Co., Ltd. The filter element is a porous medium, such as a sintered metal powder filter element and a multi-layer sintered metal wire mesh filter element. The filter can be one or more sets, preferably two or more sets, which can be switched online.

[0018] In step (1) of the method of the present invention, the liquid-phase alkali metal-liquid-phase heavy distillate oil mixture obtained by mixing alkali metal and heavy distillate oil from the catalytic cracking unit enters the filter in the filtration system. The catalyst contained in the catalytic cracking heavy distillate oil forms a filter cake on the inner surface of the filter element, thereby causing the liquid alkali metal to pass through the filter cake and filter element under high pressure, forming uniformly distributed droplets in the oil phase. The size of the alkali metal droplets can be adjusted by changing the filter element structure.

[0019] In step (1) of the method of the present invention, the liquid-phase alkali metal-liquid-phase heavy distillate oil mixture obtained by mixing alkali metal and heavy distillate oil from the catalytic cracking unit enters the filter for filtration. When the filter element pressure difference reaches a set value or the set filtration cycle is reached, backwashing medium needs to be introduced into the system to enter the backwashing stage to discharge the filter cake. The backwashing medium includes nitrogen, filtrate, and light and heavy circulating oil.

[0020] In step (2) of the method of the present invention, the residual oil feedstock includes atmospheric residue, vacuum residue, or heavy oil from other sources. The properties of the residual oil feedstock are as follows: density 0.80-0.98 g / cm³. 3 Viscosity (100℃) 50-1200 mm 2 / s, sulfur content 0.1-6.0wt.%, nitrogen content 500-5000ppm, Ni+V content 50-250ppm.

[0021] In step (2) of the method of the present invention, the alkali metal treatment device for residual oil is a stirred tank reactor with a stirring rate of 300-1500 r / min, preferably 500-1000 r / min.

[0022] In step (2) of the method of the present invention, the raw materials and alkali metals are mixed and reacted in the presence of hydrogen. The reaction involves desulfurization, denitrification, demetallization and thermal cracking.

[0023] In step (2) of the method of the present invention, the reaction conditions for the alkali metal treatment of the residue oil are as follows: reaction temperature 230-390℃, hydrogen partial pressure 0.1-18.0MPa, molar ratio of alkali metal to sulfur content of raw material 1-5, and hydrogen-to-oil volume ratio 100-1000Nm. 3 / m 3 The preferred operating conditions are: reaction temperature 280-370℃, hydrogen partial pressure 3.0-16.0 MPa, alkali metal to raw material sulfur molar ratio 2-3.5, and hydrogen-to-oil volume ratio 300-800 Nm³. 3 / m 3 .

[0024] In step (3) of the method of the present invention, the solid-liquid separation device includes various types of equipment that can realize solid-liquid separation, such as horizontal screw centrifuge, disc separator, hydrocyclone, and filter separator.

[0025] In step (3) of the method of the present invention, the solid product contains substances such as alkali metal sulfides, alkali metal nitrides, and heavy metals.

[0026] The solid product obtained in step (3) of the method of the present invention is further separated, and the heavy metals are separated and drawn out of the device; the alkali metal sulfides and alkali metal nitrides are regenerated in the regeneration device to generate alkali metals, elemental sulfur and nitrogen, wherein the alkali metals are returned to the reaction zone, and the elemental sulfur and nitrogen are drawn out of the device. The regeneration device is any type of device / process that can realize the regeneration of alkali metals, such as the alkali metal electrolytic regeneration process technology developed by Ceramatec Inc., Salt Lake City, Utah.

[0027] In step (3) of the method of the present invention, the solid content in the generated oil is controlled to be 50-500ppm, preferably 1-200ppm; the acid value of the generated oil is adjusted to be less than 1.0mgKOH / g, preferably less than 0.5mgKOH / g.

[0028] In step (3) of the method of the present invention, the solid-liquid separation is performed at least twice. A solid-liquid product A and a generated oil A are obtained through the first solid-liquid separation. An acidic additive is added to the generated oil A, and a second solid-liquid separation is performed in a purification device to obtain a solid product B and a generated oil B. The solid content in the generated oil A is controlled to be 1500-3000 ppm, preferably 1200-2500 ppm; the base value of the generated oil A is adjusted to 15-30 mg KOH / g, preferably 11-20 mg KOH / g. The acidic additive includes one or more of formic acid, hydrochloric acid, trichloroacetic acid, and phosphoric acid. It is preferred that the acidic additive is added under stirring, and more preferably under suitable temperature and stirring conditions. The temperature is generally 100-330℃, preferably 150-300℃. The stirring rate is generally 50-1500 r / min, preferably 150-1200 r / min. The purification and treatment device includes various types of reaction equipment capable of liquid-phase reactions, such as batch reactors, tubular reactors, and jet reactors. The solid content of the resulting oil B obtained after secondary solid-liquid separation is controlled to be 50-600 ppm, preferably 1-200 ppm. After treatment with acidic additives, the acid value of the resulting oil B is less than 1.0 mg KOH / g, preferably less than 0.5 mg KOH / g.

[0029] In step (4) of the method of the present invention, the generated oil obtained in step (3) enters the catalytic cracking unit alone or mixed with other raw materials.

[0030] In step (4) of the method of the present invention, the catalytic cracking can be carried out using conventional techniques in the art. The catalytic cracking unit can be one or more units, and each unit should include at least one reactor and one regenerator. The reactor of the catalytic cracking unit can be of various types, preferably a riser reactor. The catalytic cracking unit is equipped with a fractionation tower, which can be set separately for each catalytic cracking unit or shared. Compared with conventional catalytic cracking fractionation towers, the design of the catalytic cracking fractionation tower is simplified, and it only fractionates dry gas, liquefied petroleum gas, catalytic cracked gasoline, diesel, and heavy distillate.

[0031] In step (4) of the method of the present invention, the catalytic cracking catalyst can be a conventional catalytic cracking catalyst, composed of zeolite, inorganic oxides and optionally clay. The zeolite is one or more of rare earth Y-type zeolite (REY), rare earth hydrogen Y-type zeolite (REHY), ultrastable Y-type zeolite (USY), ZSM-5, ZSM-11, and ZSM-12. The inorganic oxide is silicon dioxide (SiO2) and / or aluminum oxide (Al2O3).

[0032] In step (4) of the method of the present invention, the catalytic cracking reaction conditions are: reaction temperature 400-650℃, reaction time 0.1-15s, catalyst-to-oil ratio (by weight) 2-30, pressure 0.1-0.8MPa, and regeneration temperature 600-800℃. Preferred reaction conditions are: reaction temperature 430-550℃, reaction time 0.1-8s, catalyst-to-oil ratio (by weight) 4-15, pressure 0.1-0.5MPa, and regeneration temperature 650-750℃.

[0033] This invention employs a combined process of alkali metal treatment and catalytic cracking for residue oil processing. Utilizing the high reactivity of alkali metals, the alkali metal treatment technology can remove impurities from residue oil under mild conditions. The reaction temperature of this technology is lower than that of traditional residue oil hydrotreating, effectively increasing liquid yield and thus improving the quality and yield of light oil products. Furthermore, this technology directly treats residue oil with alkali metals, eliminating the need for catalysts and waste agent disposal issues, effectively reducing equipment investment and operating costs.

[0034] For alkali metal treatment technology in residual oil, the dispersion of alkali metals in the reaction system affects the contact efficiency between the alkali metals and the oil phase, which is a key factor influencing the reaction rate and impurity removal effect. This invention heats the alkali metals to a liquid state and then mixes them with catalytic cracking heavy distillate oil before introducing them into a filter. The catalyst powder from the catalytic cracking heavy distillate oil forms a filter cake on the inner surface of the filter element. Therefore, the liquid alkali metals can form uniformly distributed droplets under the combined action of the filter cake and the filter element, improving the dispersion of the alkali metals in the reaction system, thereby enhancing the reaction rate and impurity removal effect.

[0035] The advantages of this invention are:

[0036] (1) This invention can give full play to the characteristics of high impurity removal rate and high liquid yield of alkali metal treatment technology for residual oil, and maximize the quality and yield of light oil products.

[0037] (2) In this invention, alkali metals are heated to a liquid state and then mixed with catalytic cracking heavy distillate oil before entering a filter. On the one hand, this removes catalyst powder carried in the catalytic cracking heavy distillate oil to avoid affecting the quality of the oil; on the other hand, the catalyst powder forms a filter cake on the inner surface of the filter element, allowing the liquid alkali metals to form uniformly distributed droplets under the dual action of the filter cake and the filter element, thereby increasing the dispersion of alkali metals in the reaction system and thus improving the reaction rate and the impurity removal effect.

[0038] (3) The alkali metal treatment technology for residual oil has low reaction severity and does not require high temperature and high pressure reaction conditions; it does not require catalysts and there is no waste agent treatment problem, which can effectively reduce equipment investment and operating costs and is conducive to energy conservation and environmental protection.

[0039] (4) The alkali metal treatment technology for residual oil has a high removal rate of impurities and can significantly reduce the sulfur, nitrogen and metal content in the feedstock. The resulting oil is used as feedstock for catalytic cracking units, which effectively slows down catalyst deactivation, thereby reducing the frequency of catalyst regeneration and reducing the operating cost of the unit.

[0040] (5) The heavy distillate oil from catalytic cracking is recycled to the alkali metal treatment reaction zone of the residue oil, which can dilute the residue oil feed, reduce the viscosity of the feedstock, and help improve the dispersion of alkali metals in the reaction system, reduce the reaction difficulty and the severity of processing.

[0041] (6) The catalytic cracking fractionation tower does not need to separately fractionate the catalytic cracking circulating oil and catalytic cracking slurry. They can be extracted together as heavy distillate, thereby simplifying the fractionation tower structure and reducing the investment and operating energy consumption of the unit. Attached Figure Description

[0042] The attached figure is a schematic diagram of the process flow of a residual oil processing method provided by the present invention.

[0043] 1 is a mixer, 2 is a filter, 3 is an alkali metal treatment unit for residual oil, 4 is a separation unit, 5 is a regeneration unit, 6 is a purification unit, 7 is a separation unit, 8 is a catalytic cracking unit, 9 is alkali metal, 10 is a liquid-phase alkali metal-liquid-phase heavy distillate oil mixture, 11 is a backwashing medium, 12 is residue, 13 is a mixture in which alkali metal droplets are highly dispersed in the oil phase, 14 is residual oil feedstock, 15 is hydrogen, 16 is the product of alkali metal treatment reaction, and 17 is the solid product A (heavy distillate) from alkali metal treatment. 18 is alkali metal obtained from the regeneration reaction, 19 is oil A produced by alkali metal treatment, 20 is acidic additive, 21 is the product of purification treatment reaction, 22 is oil B produced, 23 is nitrogen, 24 is elemental sulfur, 25 is heavy metal, 26 is hydrogen and hydrogen sulfide, 27 is dry gas, 28 is liquefied petroleum gas, 29 is catalytic cracking gasoline, 30 is catalytic cracking diesel, 31 is catalytic cracking heavy distillate oil, 32 is coke, and 33 is solid product B (alkali metal salt). Detailed Implementation

[0044] The method provided by the present invention will now be described with reference to the accompanying drawings.

[0045] Alkali metal from pipeline 9 and alkali metal obtained from the regeneration reaction from pipeline 18 are mixed with catalytic cracking heavy distillate oil from pipeline 31 at a certain temperature in mixer 1. The resulting liquid-phase alkali metal-liquid-phase heavy distillate oil mixture enters filter 2 via pipeline 10. During the backwashing stage, the backwashing medium enters filter 2 via pipeline 11, and the residue containing catalyst powder is extracted via pipeline 12. The mixture obtained after treatment by filter 2, with alkali metal droplets highly dispersed in the oil phase, is mixed with residue feedstock from pipeline 14 and hydrogen from pipeline 15 via pipeline 13 and then enters the residue alkali metal treatment unit 3 for reaction. The reaction products enter separator 4 via pipeline 16 for primary solid-liquid separation. Solid product A (heavy metals, alkali metal sulfides, and alkali metal nitrides) enters regenerator 5 via pipeline 17, while non-renewable heavy metals are extracted via pipeline 25. The solid alkali metal sulfides and alkali metal nitrides undergo a regeneration reaction to produce alkali metals, elemental sulfur, and nitrogen. The regenerated alkali metals are returned to mixer 1 via pipeline 18, while nitrogen and elemental sulfur are extracted via pipelines 23 and 24, respectively. The resulting product oil A after solid / liquid separation enters purification unit 6 via pipeline 19, where it reacts with acidic additives from pipeline 20 to produce hydrogen, hydrogen sulfide, and a solid-liquid mixture. Hydrogen and hydrogen sulfide are extracted via pipeline 26, and the solid-liquid mixture enters separator 7 via pipeline 21 for secondary solid-liquid separation to obtain product oil B and solid product B. Solid product B is extracted via pipeline 33. The generated oil B enters the catalytic cracking unit 8 via pipeline 22 for cracking reaction. The reaction products are separated into dry gas, liquefied petroleum gas, catalytic cracked gasoline, catalytic cracked light diesel oil, catalytic cracked heavy distillate oil and coke via a fractionation tower. The dry gas, liquefied petroleum gas, catalytic cracked gasoline, catalytic cracked light diesel oil and coke are extracted via pipelines 27, 28, 29, 30 and 32 respectively. The catalytic cracked heavy distillate oil is circulated to the mixer 1 via pipeline 31.

[0046] The following embodiments will further illustrate the method provided by the present invention, but do not limit the present invention.

[0047] The alkali metal treatment experiments of the residue oil in the examples and comparative examples were conducted on a pilot-scale residue oil alkali metal treatment device designed in the laboratory. The alkali metal used was sodium metal, and the separation device was a horizontal screw centrifuge. The acid additive used was a mixture of formic acid and acetic acid in a 1:1 mass ratio. The catalytic cracking experiments in the examples and comparative examples were conducted on a small riser reactor pilot-scale device. The commercial brand of the catalytic cracking catalyst used was CGP-2, produced by Sinopec Catalyst Changling Branch. In the catalytic cracking experiments, the heavy distillate oil referred to as catalytic cracking heavy cycle oil and catalytic cracking slurry oil. The mixer used in the examples and comparative examples was an SK-type static mixer, and the filter used was a multi-layer metal wire mesh sintered filtration technology jointly developed by China University of Petroleum and other institutions.

[0048] The residue feedstock A used in the examples and comparative examples was obtained from the atmospheric residue of the refinery, and its properties are listed in Table 1.

[0049] Example 1

[0050] This embodiment employs a combined process of alkali metal treatment and catalytic cracking for residue oil processing. Sodium metal is heated to 180°C and mixed with catalytic cracking heavy distillate oil, then fed into a mixer. The resulting mixture is filtered and then mixed with residue oil feedstock A before entering the alkali metal treatment unit. The reaction products undergo solid-liquid separation in a horizontal screw centrifuge at 3500 r / min to obtain product oil A and solid product A. The product oil A is then purified by reacting with an acidic additive in a purification unit at 150°C and a stirring rate of 200 r / min to remove alkaline impurities. Finally, it is centrifuged again at 8500 r / min to remove solid impurities before entering the catalytic cracking unit.

[0051] Comparative Example 1

[0052] This comparative example employs a fixed-bed residue hydrotreating and catalytic cracking combined process for residue processing. Residue feedstock A, catalytic cracking heavy distillate, and hydrogen are mixed and then fed into the fixed-bed residue hydrotreating unit for reaction. The resulting product oil is then fed into the catalytic cracking unit. The fixed bed uses FZC-28, FZC-30, and FZC-41 catalysts developed and manufactured by the Fushun Petrochemical Research Institute, with a catalyst loading volume ratio of 3:2:1.

[0053] The reaction conditions for fixed-bed residue hydrotreating, alkali metal treatment, and catalytic cracking are shown in Table 2. The product properties from these processes are shown in Tables 3 and 4, and the product distribution from catalytic cracking is shown in Table 5. The data in the tables show that, under conditions where the reaction severity of alkali metal treatment (280℃, 3MPa) is significantly lower than that of fixed-bed residue hydrotreating (380℃, 12MPa), the impurity removal rate of alkali metal treatment is significantly better than that of fixed-bed residue hydrotreating. Furthermore, when the oil treated by alkali metal treatment is used as feedstock in the catalytic cracking unit, the yield of light oil products is high, and the sulfur content of the gasoline fraction is lower (17.7ppm).

[0054] Table 1 Properties of Raw Materials

[0055]

[0056] Table 2 Test conditions for combined processes

[0057]

[0058] Table 3 Properties of products from alkali metal treatment / fixed-bed residue hydrotreating

[0059]

[0060] Table 4 Properties of Catalytic Cracking Products

[0061]

[0062] Table 5 Distribution of Catalytic Cracking Products

[0063]

[0064] Example 2

[0065] The process flow in this embodiment is the same as in Embodiment 1. Sodium metal is heated to 250°C and mixed with catalytic cracking heavy distillate oil, then fed into a mixer. The resulting mixture is filtered and then mixed with residue oil feedstock A before entering the residue oil alkali metal treatment unit. The primary separation is performed using a horizontal screw centrifuge at a speed of 8500 r / min. During the secondary separation, the purification unit temperature is 300°C, the stirring rate is 1200 r / min, and the horizontal screw centrifuge speed is 8500 r / min.

[0066] Example 2-1

[0067] The process flow for this comparative example is the same as in Example 1. Sodium metal is heated to 300°C and mixed with catalytic cracking heavy distillate oil, then fed into a mixer. The resulting mixture is filtered and then mixed with residue feedstock A before entering the residue alkali metal treatment unit. All parameters during the separation process are the same as in Example 2.

[0068] Example 3

[0069] The process flow in this embodiment is the same as in Embodiment 1. Sodium metal is heated to 220°C and mixed with catalytic cracking heavy distillate oil, then fed into a mixer. The resulting mixture is filtered and then mixed with residue oil feedstock A before entering the residue oil alkali metal treatment unit. The primary separation is performed using a horizontal screw centrifuge at a speed of 6000 r / min. During the secondary separation, the purification unit temperature is 275°C, the stirring rate is 700 r / min, and the horizontal screw centrifuge speed is 8500 r / min.

[0070] The reaction conditions for alkali metal treatment and catalytic cracking of residual oil are shown in Table 6, and the product properties of alkali metal treatment and catalytic cracking of residual oil are shown in Tables 7 and 8.

[0071] Table 6. Main operating conditions for alkali metal treatment and catalytic cracking of residual oil.

[0072]

[0073] Table 7. Product Properties of Alkali Metal Residue Oil Processing

[0074]

[0075] Table 8 Product Properties of Catalytic Cracking

[0076]

Claims

1. A method for processing residual oil, characterized in that: The method includes the following steps: (1) After the alkali metal is heated to liquefy it, it is mixed with the heavy distillate oil from catalytic cracking and then enters the filter in the filtration system of the catalytic cracking unit. The heating temperature is 100-280℃. The catalyst powder carried in the heavy distillate oil from catalytic cracking forms a filter cake on the inner surface of the filter element, so that the liquid alkali metal forms uniformly distributed droplets. (2) The filtered material obtained in step (1) is mixed with the residual oil raw material and fed into the residual oil alkali metal treatment device for reaction; (3) The material after the reaction in step (2) is separated into solid phase products and generated oil by solid-liquid separation; (4) The generated oil obtained in step (3) enters the catalytic cracking unit and reacts in the presence of the catalytic cracking catalyst. The reaction products are separated to obtain dry gas, liquefied gas, catalytic cracking gasoline, catalytic cracking light diesel oil, catalytic cracking heavy distillate oil and coke. The catalytic cracking heavy distillate oil repeats the process of step (1). In step (1), the alkali metal includes one or more of lithium, sodium, and potassium; In step (1), the catalytic cracking heavy distillate is a distillate with a temperature >230℃; In step (2), the reaction operating conditions are as follows: reaction temperature 230-390℃, hydrogen partial pressure 0.1-18.0MPa, alkali metal to raw material sulfur molar ratio 1-5, and hydrogen-to-oil volume ratio 100-1000 Nm. 3 / m 3 .

2. The method according to claim 1, characterized in that: The heating temperature is 180-250℃.

3. The method according to claim 1, characterized in that: In step (1), the catalytic cracking unit filtration system is a porous metal filtration system, and the filter is one or more sets.

4. The method according to claim 1, characterized in that: In step (1), the catalytic cracking unit filtration system is either a Hypulse LSI type filtration system or a fully automatic slurry filter system.

5. The method according to claim 3, characterized in that: The filters are in sets of two or more.

6. The method according to claim 1, characterized in that: In step (2), the residual oil feedstock includes atmospheric residue, vacuum residue, or heavy oil from other sources; the properties of the residual oil feedstock are as follows: density 0.80-0.98 g / cm³. 3 Viscosity at 100℃: 50-1200 mm 2 / s, sulfur content 0.1-6.0wt.%, nitrogen content 500-5000ppm, Ni+V content 50-250ppm.

7. The method according to claim 1, characterized in that: In step (2), the alkali metal treatment device for residual oil is a stirred tank reactor with a stirring rate of 300-1500 r / min.

8. The method according to claim 7, characterized in that: The stirring speed is 500-1000 r / min.

9. The method according to claim 1, characterized in that: In step (2), the reaction operating conditions are as follows: reaction temperature 280-370℃, hydrogen partial pressure 3.0-16.0MPa, alkali metal to raw material sulfur molar ratio 2-3.5, and hydrogen-to-oil volume ratio 300-800 Nm. 3 / m 3 .

10. The method according to claim 1, characterized in that: In step (3), the solid-liquid separation device is one of the following: a horizontal screw centrifuge, a disc separator, a hydrocyclone, and a filter separator.

11. The method according to claim 1, characterized in that: The solid products obtained in step (3) are further separated, and the heavy metals are separated and taken out of the device; the alkali metal sulfides and alkali metal nitrides are regenerated in the regeneration device to generate alkali metals, elemental sulfur and nitrogen, wherein the alkali metals are returned to the mixer described in step (1), and the elemental sulfur and nitrogen are taken out of the device.

12. The method according to claim 1, characterized in that: The catalytic cracking reaction conditions described in step (4) are: reaction temperature 400-650℃, reaction time 0.1-15s, agent-to-oil weight ratio 2-30, pressure 0.1-0.8MPa, and regeneration temperature 600-800℃.

13. The method according to claim 12, characterized in that: The catalytic cracking reaction conditions described in step (4) are: reaction temperature 430-550℃, reaction time 0.1-8s, agent-to-oil weight ratio 4-15, pressure 0.1-0.5MPa, and regeneration temperature 650-750℃.

14. The method according to claim 1, characterized in that: The catalytic cracking catalyst in step (4) is composed of zeolite, inorganic oxide and optional clay. The zeolite is one or more of rare earth Y-type zeolite, ultrastable Y-type zeolite, ZSM-5, ZSM-11 and ZSM-12. The inorganic oxide is silicon dioxide and / or aluminum oxide.

15. The method according to claim 1, characterized in that: The catalytic cracking catalyst described in step (4) consists of zeolite, inorganic oxides and optional clay, wherein the zeolite is rare earth hydrogen Y-type zeolite.

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