Feedstock oil catalytic cracking reactor

Abstract

A raw material oil catalytic cracking reaction device, comprising: a reactor and a settler arranged above the reactor, wherein the lower section of the riser extends into the reactor through the bottom of the reactor, the lower section of the riser in the reactor comprises a variable diameter section, the cross section of the variable diameter section gradually increases from top to bottom, a plurality of openings are arranged on the wall of the variable diameter section of the lower section of the riser, one end of the lower section of the riser in the reactor is open, and the lower section of the lower section of the riser below the variable diameter section is connected with the regenerant inclined pipe. Through the structure of the lower section of the riser arranged in the reaction device, appropriate high-temperature catalysts enter the annular gap reaction zone between the reactor and the lower section of the riser to contact and react with the raw material oil, the yield of low olefins such as ethylene and propylene is improved, and the yield of methane is reduced.

Description

Technical Field

[0001] This application relates to a fluidized bed reactor, specifically a feedstock oil catalytic cracking reactor, belonging to the petrochemical field. Background Technology

[0002] With advancements in new energy vehicle technology and improved engine efficiency, coupled with diminishing returns on refined oil production, refining capacity will gradually exhibit structural overcapacity. Meanwhile, demand for ethylene, propylene, and aromatics is increasing, creating a contradiction with traditional refining processes. In recent years, some companies have begun to integrate and innovate traditional refining processes or even completely overturn traditional refining procedures, elevating integrated refining and chemical production to a new level: Crude Oil to Chemicals (COTC). In terms of the yield of crude oil converted into basic petrochemical feedstocks, the yields for various process routes are roughly as follows: traditional fuel-type refineries 5%–10%, conventional integrated refining and chemical plants 10%–20%, and COTC plants exceeding 40%, potentially reaching 80%. Therefore, crude oil production of chemical feedstocks is a primary means for petroleum refining enterprises to transform, upgrade, and improve efficiency.

[0003] ExxonMobil's direct catalytic cracking technology for olefins abroad employs a combination of flash evaporation and steam cracking. Domestically, crude oil steam cracking and catalytic cracking technologies have also been developed, but these utilize light crude oil. High-temperature reactions are often used in the direct catalytic cracking of paraffinic crude oil, but these high temperatures can easily lead to excessive thermal cracking, producing large amounts of methane and resulting in low yields of low-carbon olefins.

[0004] Chinese patent application CN202010099964.1 discloses a method for increasing the production of low-carbon olefins through thermal cracking of petroleum hydrocarbons. The method involves contacting petroleum hydrocarbon feedstock oil and water vapor with a polymerization inhibitor and a contacting agent at a reaction temperature of 600-900℃ in a thermal cracking reactor, resulting in a thermal cracking reaction. The reaction temperature is 700℃, and the feedstock concentration is 0.86 g / cm³. -3 When processing wax oil, the composition is ethylene + propylene 38.92%. No byproducts such as methane are mentioned.

[0005] Chinese patent application CN101293806A discloses a catalytic conversion method for improving the yield of low-carbon olefins. In this method, the feedstock is injected through a nozzle into a riser and / or a fluidized bed reactor, where it contacts and reacts with the catalyst. Hydrogen-rich gas is injected into the reactor to separate the reacted oil and gas from the catalyst that has been coked after the reaction. This method suppresses the re-conversion reaction of low-carbon olefins after their formation by injecting hydrogen-rich gas into the reactor, thereby increasing the yield of low-carbon olefins, especially propylene. However, it has little effect on reducing dry gas yield or improving heavy oil conversion.

[0006] Chinese patent application CN200910210330.2 discloses a catalytic cracking method for heavy oil catalytic cracking, achieving high heavy oil conversion and propylene yield, but low dry gas and coke yields. The first riser reactor uses heavy feedstocks, primarily heavy hydrocarbons and / or various animal and vegetable oils rich in hydrocarbons, and is divided into two reaction zones: Zone I has a reaction temperature of 500–700°C; Zone II has a reaction temperature of 480–600°C. The second riser uses light feedstocks and heavy oil as feedstocks, with a reaction temperature of 520–580°C. The use of multiple reactors and multiple reaction zones promotes feedstock conversion and increases olefin yield. Summary of the Invention

[0007] The primary objective of this application is to improve the selectivity of low-carbon olefins such as ethylene and propylene in the catalytic cracking of feedstock oil, and to reduce the yield of methane.

[0008] The second objective of this application is to reduce or even avoid coking in the settler during the catalytic cracking reaction of feedstock oil, and to avoid the problem of catalyst runoff in the unit.

[0009] The feedstock catalytic cracking reactor provided in this application includes: a reactor and a settling tank disposed above the reactor. The lower section of the riser extends into the reactor through the bottom of the reactor. The lower section of the riser inside the reactor includes a variable diameter section. The cross-section of the variable diameter section gradually increases from top to bottom. Multiple openings are provided on the wall of the variable diameter section of the lower section of the riser. One end of the lower section of the riser inside the reactor is open. The lower section of the riser below the variable diameter section of the lower section of the riser is configured to be connected to the regenerator inclined tube.

[0010] By utilizing the structure of the lower section of the riser in the reaction apparatus of this application, an appropriate high-temperature catalyst enters the annular reaction zone between the reactor and the lower section of the riser to contact and react with the feedstock oil, thereby increasing the yield of low olefins such as ethylene and propylene, while reducing the yield of methane.

[0011] The settling device of the feedstock catalytic cracking reactor provided in this application includes: a settling tank, a primary separator and a cyclone separator. The primary separator and the cyclone separator are located in the settling tank. The primary separator is configured to be connected to the reactor side wall through an outlet. The primary separator includes a bend and a feed pipe connected to the bend. The bend bends upward from the connection with the reactor side wall.

[0012] The oil and gas discharged from the reactor, along with the catalyst, pass through the bend in the primary separator. Most of the catalyst is discharged through the feed pipe of the primary separator, while the oil and gas enter the cyclone separator for further gas-solid separation. This significantly reduces the amount of oil and gas that directly enters the settling tank, preventing coking in the settling tank and reducing the workload of the cyclone separator. Attached Figure Description

[0013] Figure 1 A schematic diagram of one embodiment of a feedstock oil catalytic cracking reactor.

[0014] Figure 2 A schematic diagram of the structure within the dense phase transport reaction section.

[0015] Figure 3 Cross-sectional view of the primary separator inside the settling tank.

[0016] Figure 4 A schematic diagram of the straight-tube reactor used in Comparative Example 1.

[0017] 1. Pre-lifting medium, 2. Pre-lifting pipe, 3. Regeneration inclined pipe, 4. Distribution pipe, 5. Raw material nozzle, 6. Lower section of the riser, 7. Variable diameter section of the lower riser, 8. Opening on the side wall of the riser, 9. Upper outlet of the lower section of the riser, 10. Upward oil and gas, 11. Regenerant, 12. Riser, 13. Reactor settling tank, 14. Oil and gas separation system, 15. Pre-regeneration inclined pipe, 16. Regenerator settling tank, 17. Flue gas, 18. 19. Conveying medium; 20. Primary gas-solid separator; 21. Primary gas-solid separator feed pipe; 22. Coarse cyclone separator; 23. High-efficiency cyclone separator; 24. Guide cone; 25. Primary gas-solid separator feed pipe air-lift section; 26. First air-lift medium; 27. Coarse cyclone separator material leg degassing section; 28. Coarse cyclone separator feed pipe; 29. ​​Air and fuel; 30. Dense phase conveying reaction section; 31. Second air-lift medium. Detailed Implementation

[0018] The feedstock catalytic cracking reactor of the present invention is described in further detail below. The scope of protection of this application is not limited thereto, but is defined by the claims. Certain specific details disclosed provide a comprehensive understanding of the various disclosed embodiments. However, those skilled in the art will recognize that embodiments can be implemented using other materials, etc., without employing one or more of these specific details.

[0019] Unless the context otherwise requires, the terms “comprising” and “including” in the specification and claims shall be understood as open-ended and inclusive, meaning “including, but not limited to”.

[0020] The terms "implementation," "an implementation," "another implementation," or "certain implementations" used in this specification refer to specific features, structures, or characteristics described in relation to the implementation, which are included in at least one implementation. Therefore, "implementation," "an implementation," "another implementation," or "certain implementations" do not necessarily all refer to the same implementation. Furthermore, specific features, structures, or characteristics can be combined in any way within one or more implementations. Each feature disclosed in this specification can be replaced by any alternative feature that provides the same, equivalent, or similar purpose. Therefore, unless otherwise specified, the disclosed features are merely general examples of equivalent or similar features.

[0021] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. Unless otherwise stated, all percentages, ratios, proportions, or parts are by weight.

[0022] The term "gas-solid separation efficiency" refers to the mass fraction of catalyst that is separated into gas and solid phases from the total catalyst entering the separator.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as are familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention. The preferred embodiments and materials described herein are for illustrative purposes only.

[0024] In existing feedstock catalytic cracking reactions, maintaining the catalytic cracking temperature within the reactor requires a relatively high input catalyst temperature. This high temperature, due to the instantaneous high temperature upon contact between the feedstock and the high-temperature catalyst, leads to excessive thermal cracking, resulting in a high methane yield. Furthermore, the low catalyst circulation rate within the reactor results in incomplete feedstock conversion and low selectivity for low-olefins such as ethylene and propylene. The feedstock catalytic cracking reactor proposed in this application addresses these shortcomings.

[0025] On the one hand, the feedstock catalytic cracking reactor provided in this application includes: a reactor and a settling tank disposed above the reactor, wherein the lower section of the riser extends into the reactor through the bottom of the reactor, the lower section of the riser in the reactor includes a variable diameter section, the cross-section of the variable diameter section gradually increases from top to bottom, a plurality of openings are provided on the wall of the variable diameter section of the lower section of the riser, one end of the lower section of the riser in the reactor is open, and the lower section of the riser below the variable diameter section is configured to be connected to the regenerator inclined tube.

[0026] In this application, multiple openings are provided on the variable-diameter section of the lower riser section as outlets for the high-temperature catalyst. The regenerated high-temperature catalyst enters through the lower part of the lower riser section, moves upward under the influence of the lifting medium, and enters the reactor through the openings in the variable-diameter section and the upper opening. The regenerated high-temperature catalyst can enter the annular reaction zone between the lower riser section and the reactor wall from multiple directions, increasing the catalyst circulation rate. Relatively speaking, the temperature of the high-temperature catalyst will not be excessively high. Therefore, it avoids excessive thermal cracking caused by excessively high instantaneous temperature when the feedstock comes into contact with the high-temperature catalyst, thus preventing a reduction in methane yield. Furthermore, sufficient contact between the feedstock oil and the catalyst within the annular reaction zone ensures the yield of low-carbon olefins such as ethylene and propylene.

[0027] Typically, the lower section of the reactor and riser has a circular cross-section.

[0028] In some implementations, the lower section of the riser pipe has a truncated cone shape, and in the axial direction, the angle between the pipe wall of the lower section and the axis is 1-88°.

[0029] In the preferred embodiment, the angle between the pipe wall of the variable diameter section and the axis is 2-30°.

[0030] By providing openings for catalyst ejection on the inclined tube wall of the truncated cone-shaped variable-diameter section, the catalyst can be ejected from the side wall into the annular space without increasing the reactor pressure. This low pressure helps maintain a high olefin yield. On the other hand, the high-temperature catalyst can be injected obliquely upwards into the annular space through the openings, ensuring full contact between the catalyst and the feedstock. The catalyst can also continue to move upwards together, further contacting and reacting with the high-temperature catalyst ejected from the upper opening, thus ensuring that the temperature remains essentially constant within the annular reaction region.

[0031] In some implementations, at least two openings are provided on the same cross-section of the pipe wall of the variable diameter section, and they are evenly distributed.

[0032] In some implementations, at least four openings are provided on the same cross-section of the pipe wall of the variable diameter section, and they are evenly distributed.

[0033] In the axial direction, openings are provided on at least two cross sections of the pipe wall of the variable diameter section.

[0034] On the pipe wall of the reducing section, the total area of ​​the openings accounts for 10-80% of the total area of ​​the reducing section in the lower part of the riser.

[0035] The mass of catalyst entering the annular reaction zone can be controlled by increasing the number and area of ​​openings on the sidewall of the lower section of the tube, thereby controlling the reaction temperature in the annular reaction zone. Therefore, for different reaction systems, the number and area of ​​openings are determined to control the temperature of the annular reaction zone.

[0036] In some embodiments, the reactor includes an interconnected dense-phase transport bed reaction section and a riser, the dense-phase transport bed reaction section being located below the riser, wherein the lower section of the riser extends into the dense-phase transport bed reaction section through the bottom of the reactor.

[0037] The ratio of the length of the variable diameter section of the lower section of the riser in the dense phase conveying bed reactor to the total length of the dense phase conveying bed reaction section is 0.2-0.8:1, preferably 0.3-0.6:1.

[0038] The diameter ratio of the riser and the dense phase conveying bed reaction section in the reactor is 0.1-0.8:1, preferably 0.2-0.8:1.

[0039] The diameter ratio of the lower section of the riser pipe to the reaction section of the dense phase conveying bed is 0.1-0.8:1, preferably 0.2-0.8:1.

[0040] By setting the conveying bed in the dense phase section of the riser according to the above-mentioned ratio, a constant-temperature reaction zone is formed that allows the raw materials and catalyst to fully contact, ensuring the full conversion of the raw materials and the generation of the target product olefins.

[0041] In some implementations, a gas distributor is provided in the annular reaction zone between the lower section of the riser and the dense phase transport reaction section to distribute the dilution medium.

[0042] The dilution medium generally refers to nitrogen or steam, and some reactions are called atomized steam.

[0043] The feedstock oil is introduced into the annular reaction zone between the lower section of the riser and the dense phase transport reaction zone. Preferably, the feedstock oil is injected into the annular reaction zone below the lower section of the riser.

[0044] In some embodiments, the reaction apparatus further includes a pre-lifting pipe, which is located within the lower section of the riser. The outlet end of the pre-lifting pipe is positioned above the upper edge of the outlet of the regeneration inclined tube, not exceeding 0.5 m, preferably not exceeding 0.2 m. This arrangement allows for smooth upward movement of the catalyst.

[0045] In some embodiments, the ratio of the pre-lifting pipe diameter to the lower section diameter of the lifting pipe is 0.1-0.9:1, preferably 0.2-0.7:1. The linear velocity at the pre-lifting pipe outlet is controlled at 1-40 m / s, preferably 1-20 m / s.

[0046] The reaction apparatus of this application is used for catalytic cracking reactions of one or more of crude oil, wax oil, heavy oil, gasoline, naphtha, diesel oil or hydrocarbons.

[0047] In some embodiments, the reaction apparatus of this application is used in crude oil catalytic cracking reactions.

[0048] A crude oil catalytic cracking reaction using the above-mentioned reaction apparatus, wherein the reaction temperature in the annular reaction zone is controlled at 400-800℃; the residence time is controlled at 0.1-5s; and the catalyst-to-oil ratio is controlled between 5-60.

[0049] In the preferred embodiment, the reaction temperature in the annular gap reaction zone is controlled at 500-750℃.

[0050] In the preferred embodiment, the residence time in the annular reaction zone is controlled to be preferably 0.2-3 seconds.

[0051] The residence time of the entire reactor is controlled between 1 and 8 seconds, preferably 2 to 7 seconds.

[0052] Under the above reaction conditions, the yields of ethylene and propylene, the catalytic cracking products of crude oil, are high, while the yield of methane is low.

[0053] In some embodiments, the outlet gas velocity of the opening in the lower section of the riser wall within the dense phase transport reaction section is 0.1-20 m / s, preferably 1-10 m / s. The average linear velocity of the catalyst outlet at the upper opening of the lower section of the riser is 0.2-20 m / s, preferably 1-15 m / s.

[0054] The average linear velocity at the outlet of the dense phase conveying reaction section is controlled at 1-20 m / s, preferably 3-15 m / s.

[0055] By limiting the catalyst rate as described above, sufficient reaction time is ensured for the feedstock and catalyst oil.

[0056] In some implementations, the distance between the dilution medium distribution pipe and the raw material nozzle is in the ratio of (0.1-10):1 to the riser pipe diameter.

[0057] In some implementations, the mass ratio between dilution gas and raw material is 0.1-0.7:1, preferably 0.1-0.6:1.

[0058] In some implementations, the average linear velocity of the gas in the cross-sectional area of ​​the riser outlet is controlled at 0.1-50 m / s, preferably 1-20 m / s.

[0059] The crude oil catalytic cracking method described in this application can achieve a yield of over 46% for low olefins such as ethylene and propylene, and less than 14% for methane.

[0060] On the other hand, the feedstock catalytic cracking reactor of this application also includes a settling device, which includes a settling tank, a primary separator, and a cyclone separator. The primary separator and the cyclone separator are located in the settling tank. The primary separator includes a bend and a feed pipe connected to the bend. The first end of the bend is connected to an outlet on the side wall of the reactor, and the second end of the bend is connected to the cyclone separator. The bend bends upward from the connection with the side wall of the reactor. The feed pipe includes a feed pipe air-lift section and a feed pipe conveying section.

[0061] In some embodiments, the bend in the primary separator includes a smoothly transitioning curved section; from the first end to the second end of the bend, relative to the central axis of the reactor, the curved section first extends away from the central axis and then extends closer to the central axis.

[0062] The primary separator serves to initially separate the catalyst. When the catalyst and oil / gas enter the primary separator, they directly collide with the curved sidewalls, causing the catalyst to settle naturally. Most of the oil / gas and a small amount of catalyst enter the subsequent separation system of the cyclone separator. The settled catalyst, after stripping, enters the settling tank, thereby reducing the amount of oil / gas carried in the catalyst.

[0063] The catalyst separated by the primary separator reduces the separation load on the subsequent cyclone separator, preventing a large amount of catalyst from entering the cyclone separator during unit fluctuations and hindering catalyst separation. Simultaneously, the primary separator includes a stripping section to remove oil and gas from the catalyst, reducing the proportion of oil and gas carried by the catalyst. This allows for more efficient stripping of the catalyst in the settling tank, reducing coking in the settling tank.

[0064] Preferably, in the longitudinal section of the curved section, the side closest to the central axis of the reactor is arc-shaped with a central angle of 120° to 240°.

[0065] In some implementations, the side closest to the central axis of the reactor in the longitudinal section of the curved section is arc-shaped with a central angle of 180°.

[0066] In some implementations, the lower edge of the bend is connected to the upper end of the feed pipe in the longitudinal section of the bend, so that the feed pipe and the bend are in communication.

[0067] The lower edge of the bend between the first end of the bend and the feed pipe is arc-shaped, and the central angle of the arc is 0 to 90°. Preferably, the central angle of the arc is 5-80°.

[0068] The curved section structure of the primary separator in this application uses the curvature to block most of the catalyst from the oil and gas discharged from the reactor; to some extent, it can stabilize the oil and gas velocity, thereby reducing the amount of catalyst entering the coarse cyclone separator inlet, reducing the load on the cyclone separator, and thus reducing catalyst loss.

[0069] During start-up, shutdown, or abnormal operating conditions, catalyst circulation is often unstable, and gas velocity fluctuates. This prevents the cyclone separator from achieving its designed separation efficiency, resulting in the catalyst failing to separate properly and instead entering the subsequent fractionation system along with the oil and gas. Even during start-up, shutdown, or abnormal operating conditions, because the oil, gas, and catalyst pass through the primary separator described in this application before entering the cyclone separator, the catalyst and oil entering the cyclone separator can achieve excellent gas-solid separation, thereby reducing catalyst loss.

[0070] In some implementations, the cross-section of the bend first increases and then decreases from the first end to the second end.

[0071] The reactor is a riser reactor, and the ratio of the cross-sectional diameter of the primary separator bend to the riser diameter is (1-5):1. Preferably, the ratio of the cross-sectional diameter of the primary separator bend to the riser diameter is (1-3):1.

[0072] By setting the diameter ratio, the gas velocity entering the primary separator can be controlled, and the amount of catalyst deposited can be controlled.

[0073] In some embodiments, the feed pipe of the primary separator includes a feed pipe air lift section and a feed pipe conveying section. The upper end of the feed pipe air lift section is connected to the lower edge of the bend, and the lower end of the feed pipe air lift section is connected to the upper end of the feed pipe conveying section. A gas distributor is provided in the feed pipe air lift section.

[0074] The stripping medium enters the stripping section of the feed pipe via a gas distributor. The catalyst, after passing through the primary separator, also enters the stripping section of the feed pipe, where the stripping medium degasses the catalyst, removing any carried oil and gas. The degassed catalyst then enters the conveying section of the feed pipe. This significantly reduces the amount of oil and gas carried in the catalyst discharged through the feed pipe.

[0075] The stripping medium includes nitrogen or water vapor.

[0076] Preferably, the outlet gas velocity of the stripping medium at the gas distributor is 0.1-5 m / s, more preferably 0.5-3 m / s.

[0077] In some embodiments, the diameter ratio of the feed pipe conveying section to the feed pipe lift section in the primary separator is (0.1-1):1. Preferably, the diameter ratio of the feed pipe conveying section to the feed pipe lift section is (0.5-0.8):1.

[0078] The diameter of the feed pipe conveying section is smaller than that of the stripping section, which can reduce the downward speed of the catalyst and allow the oil and gas carried in the catalyst to be removed more completely.

[0079] In some embodiments, a guide cone is provided below the outlet of the feeding section conveying pipe. The guide cone is a conical structure with a cross-section that gradually increases from top to bottom, and the conical surface of the conical structure gradually bends away from the center line of the cone from the apex to the bottom edge.

[0080] Compared to the end with the largest cross-section of the guide cone, the end with the smallest cross-section of the guide cone is closer to the outlet of the feeding section conveying pipe.

[0081] The guide cone can be fixed below the outlet of the feed section conveying pipe using various methods available in the art. For example, it can be fixed to the wall of the settling tank using a support frame, or fixed to the primary separator. This application does not impose any limitations, as long as the fixing element does not substantially affect the movement of the catalyst.

[0082] The purpose of the guide cone is to buffer the force of the catalyst falling into the settler, reduce the impact on the catalyst, and prevent the catalyst from breaking due to impact. At the same time, it also serves to disperse the catalyst.

[0083] In some implementations, the ratio of the distance between the lower surface of the guide cone and the outlet of the primary separator feed pipe to the diameter of the feed port is (0.5-3):1.

[0084] In some implementations, the lower surface of the guide cone is circular, and the ratio of the diameter of the lower bottom surface of the guide cone to the diameter of the discharge port is (1-5):1.

[0085] In some implementations, the area of ​​the lower bottom of the guide cone is larger than the area of ​​the outlet.

[0086] The catalyst and oil gas discharged from the reactor outlet undergo gas-solid separation in the primary separator, achieving a gas-solid separation efficiency of 50-95%. The oil gas separated in the primary separator carries a small amount of catalyst into the cyclone separator, reducing the load on the cyclone separator.

[0087] In some embodiments, the cyclone separator of this application includes a coarse cyclone separator and a high-efficiency cyclone separator, with the outlet of the primary separator connected to the coarse cyclone separator.

[0088] The coarse cyclone separator includes a main body and a feed pipe. The feed pipe includes a degassing section and a conveying section. The upper end of the degassing section is connected to the lower end of the main body, and the lower end of the degassing section is connected to the upper end of the conveying section.

[0089] In the degassing section of the feed pipe of the coarse cyclone separator.

[0090] In some embodiments, a guide cone is provided below the outlet of the feed section of the coarse cyclone separator. The guide cone is a conical structure with a cross-section that gradually increases from top to bottom, and the conical surface of the conical structure gradually bends away from the center line of the cone from the apex to the bottom edge.

[0091] In some implementations, the ratio of the distance between the bottom surface of the guide cone and the outlet of the coarse cyclone separator discharge pipe to the discharge port diameter is (0.5-3):1.

[0092] To further improve gas-solid separation, the catalyst and oil gas pass through a coarse cyclone separator and then enter a high-efficiency cyclone separator. The coarse cyclone separator and the high-efficiency cyclone separator are connected by a straight pipe.

[0093] The settling device of this application can be used as a settling device in a reactor for catalytic cracking reaction or catalytic fission, or as a settling device in a catalyst regenerator.

[0094] The settler of this application is preferably suitable for catalytic cracking or cracking reaction units, wherein the mass ratio of catalyst to feedstock is 5-80, and the reaction temperature is 500-800℃.

[0095] The main technical advantages of this invention are as follows: By sequentially setting a gas-solid primary separator, a coarse cyclone separator, and a high-efficiency cyclone separator at the riser outlet, the gas-solid primary separator is used to perform preliminary separation of oil and gas and catalyst, separating most of the catalyst and reducing the load on the coarse cyclone separator, thereby avoiding catalyst runoff; at the same time, by setting stripping sections or degassing sections in the lower part of the gas-solid primary separator and the coarse cyclone separator, the oil and gas carried by the catalyst are removed, thereby avoiding coking in the settling tank and improving the unit's resistance to fluctuations.

[0096] The reaction system for catalytic cracking of feedstock oil according to the present invention is further illustrated below with reference to specific embodiments.

[0097] Example 1

[0098] like Figure 1 As shown, the feedstock catalytic cracking reaction system of this embodiment includes a reaction apparatus and a catalyst regeneration apparatus. The reaction apparatus includes a reactor and a reactor settling tank 13 located above the reactor. The reactor includes a lower section 6 of a riser pipe, a dense phase conveying bed reaction section 30, and a riser pipe 12, which are connected and communicated sequentially from bottom to top. The lower section 6 of the riser pipe extends into the dense phase conveying bed reaction section 30 through the bottom of the dense phase conveying bed reaction section 30.

[0099] In this embodiment, the lower section of the riser, the dense phase conveying bed reaction section, and the riser all have circular cross-sections. The diameter of the dense phase conveying bed reaction section is larger than that of the lower section of the riser and the riser itself.

[0100] like Figure 2As shown, the lower section 6 of the riser tube in the dense phase conveying bed reaction section 30 includes a variable diameter section 7, which is frustum-shaped. The angle between the tube wall and the axis of the variable diameter section is preferably 2-30°. The variable diameter section 7 is located in the upper part of the lower section of the riser tube, and the upper end of the lower section 6 is an opening 9. Multiple openings are provided on the peripheral wall of the variable diameter section 7, with at least four openings 8 evenly distributed in the same circumferential direction, and openings provided on at least two circumferences in the axial direction. The total area of ​​the openings accounts for 10-80% of the total area of ​​the variable diameter section of the riser tube. Preferably, the ratio of the length of the variable diameter section of the lower section of the riser tube to the total length of the dense phase conveying bed reaction section 30 is 0.2-0.8:1, preferably 0.3-0.6:1. The diameter ratio of the riser tube / lower section of the riser tube and the dense phase conveying bed reaction section of the reactor is 0.1-0.8:1, preferably 0.2-0.8:1.

[0101] A gas distributor for distributing the dilution medium is installed in the annular reaction zone between the lower section of the riser and the dense phase transport reaction section; preferably, the distributor is located below the variable diameter section or below the lowest opening of the lower section of the riser. The nozzle 5 for the feedstock oil (e.g., crude oil) is located above the gas distributor 4 for the dilution medium.

[0102] The lower section of the riser is a straight pipe, which is connected to the regeneration inclined pipe 3. The pre-lift pipe 2 is located inside the straight pipe. The outlet of the pre-lift pipe 2 is located above the upper edge of the outlet of the regeneration inclined pipe, not exceeding 0.5m, preferably not exceeding 0.2m.

[0103] like Figure 1 As shown, the lower section 6 of the riser is connected to the regenerator settling tank 16 via the regeneration inclined pipe 3. The regenerated catalyst 11 enters the lower section of the riser through the regeneration inclined pipe 3. The pre-lifting medium in the pre-lifting pipe 2 drives the regenerated catalyst 11 upward and into the variable diameter section 7 of the lower section 6. The regenerated catalyst enters the dense phase transport reaction section 30 through the opening 8 in the wall of the variable diameter section and the upper opening 9. In the annular reaction zone between the dense phase transport reaction section 30 and the lower section 6 of the riser, the feedstock oil (e.g., crude oil) and dilution medium enter the annular reaction zone and fully contact and react with the regenerated catalyst in the annular reaction zone. Subsequently, the oil and gas and the catalyst move upward together into the riser 12, and then together into the reactor settling tank 13 for gas-solid separation. The separated oil and gas 14 are discharged from the reactor settling tank and enter the separation system. The separated regenerated agent is transported to the regenerator 18 through the regenerated inclined pipe and the transport medium 19. Air and fuel 29 are introduced at the bottom of the regenerator to regenerate the regenerated agent. The regenerated catalyst and flue gas enter the regenerator settling tank 16 for gas-solid separation, and the flue gas 17 is discharged outside the regenerator settling tank 16. The second stripping medium 31 is introduced into both the reactor regenerator 13 and the regenerator settling tank 16.

[0104] Example 2

[0105] Based on Example 1, this example further describes the arrangement of the separator within the reactor settling tank 13. (See reference...) Figure 1 and Figure 3 The reactor settling tank 13 is equipped with a primary separator 20, a coarse cyclone separator 22, and a high-efficiency cyclone separator 23. The riser pipe 2 can extend into or outside the reactor settling tank 13. Regardless of the arrangement of the riser pipe 12, its sidewall is connected to the first end of the primary separator 20, the second end of the primary separator 20 is connected to the coarse cyclone separator 22, and the coarse cyclone separator 22 is connected to the high-efficiency cyclone separator 23.

[0106] Combined as attached Figure 3 The structure of the primary separator and the coarse cyclone separator is further described in detail.

[0107] The primary separator 20 is connected to the side wall of the riser pipe 12. The primary separator 20 includes a bend and a feed pipe connected to the bend. The first end of the bend of the primary separator 20 is connected to the riser pipe 12, and the bend bends upward. The second end of the bend is connected to the coarse cyclone separator 22. In the longitudinal section of the bend, the side closest to the central axis of the riser pipe 12 (the upper edge) is semi-circular, and the side furthest from the central axis of the riser pipe 12 (the lower edge) is arc-shaped, with a central angle of 80°.

[0108] The primary separator 20's feed pipe includes a feed pipe conveying section 21 and a feed pipe air lift section 25. The feed pipe air lift section 25 is located above the feed pipe conveying section 21, and its upper end is connected to and communicates with the lower edge of the bend. A guide cone 24 is provided below the feed pipe conveying section 21. The diameter of the primary separator's feed pipe air lift section 25 is three times the diameter of the lift pipe 3 and three times the diameter of the feed pipe conveying section 21. The length ratio of the primary separator's feed pipe air lift section to the feed pipe conveying section is 1:2. The distance between the guide cone 24 and the lower opening of the primary separator's feed pipe conveying section 21 is 0.3m.

[0109] After the oil and gas pass through the primary gas-solid separator, 80% of the catalyst enters the gas lift section 25 of the primary gas-solid separator feed pipe. The first gas lift medium, water vapor 26, enters the gas lift section of the primary gas-solid separator feed pipe through the distribution pipe to remove part of the oil and gas. The catalyst passes through the conveying section 21 of the primary gas-solid separator feed pipe downwards, and after passing through the guide cone 24, it is redistributed and enters the settling tank.

[0110] The catalyst discharged from the riser 12 outlet, along with the oil and gas, enters the primary separator 20, coarse cyclone separator 22, and high-efficiency cyclone separator 23 within the settler for gas-solid separation. The separated oil and gas then enter oil and gas 14 to the separation system.

[0111] Example 3

[0112] Based on Example 2, this example further defines the structure of the coarse cyclone separator.

[0113] The oil, gas and catalyst that have been initially separated by the primary separator 20 enter the coarse cyclone separator 22 for further separation.

[0114] The upper part of the primary separator is bent and connected to the side wall of the coarse cyclone separator in an arc shape. On the longitudinal section of the bend, the side away from the central axis of the riser 12 is a smooth surface. That is, on the side away from the central axis of the riser 12, there are no further restrictions on the degree of bending on the side away from the central axis of the riser 12 between the feed pipe and the inlet of the coarse cyclone separator, and the ratio of the cross section of each part of the bend to the diameter of the riser pipe should satisfy (1-5):1.

[0115] The coarse cyclone separator includes a main body, a degassing section 27 of the coarse cyclone separator's feed pipe, and a conveying section 28 of the feed pipe, connected sequentially from top to bottom. A flow cone 24 is installed below the outlet of the conveying section 28. After the gas is degassed in the degassing section 27 of the feed pipe, it enters the coarse cyclone separator's feed pipe 28 and is then dispersed into the settling tank by the flow cone 24.

[0116] Preferably, the length ratio of the main body of the coarse cyclone separator 22 to the degassing section 27 of the coarse cyclone separator discharge pipe is 1:1, and the ratio of the diameter of the necking point between the two to the diameter of the coarse cyclone separator 22 is 0.5:1. The diameter ratio of the conveying section 28 of the coarse cyclone separator discharge pipe to the degassing section 27 of the coarse cyclone separator discharge pipe is 0.5:1, and the length ratio is 2:1.

[0117] After entering the coarse cyclone separator, the oil and gas and the catalyst enter the high-efficiency cyclone separator 23. The catalyst after the oil and gas are removed enters the settling tank through the feed pipe. Together with the catalyst separated by the gas-solid primary separator and the coarse cyclone separator, it enters the regenerator for coking through the waiting inclined tube.

[0118] The reactor configuration using the settling tank structure of Example 3 was employed. The reaction conditions were as follows: feedstock was Daqing crude oil; catalyst was MMC-2 catalytic cracking catalyst; the mass ratio of catalyst to feedstock was 30; and the reaction temperature was controlled at approximately 500°C. After reaction, the mixture was separated by a settling tank, with catalyst loss of only 1%. This indicates low catalyst loss and strong resistance to fluctuations in the reactor's performance.

[0119] Examples 4-6 below use the reactor from Example 1 to carry out catalytic cracking of crude oil. The cracking catalyst prepared in Example 8 of patent CN202010022024.2 is used.

[0120] Example 4

[0121] The reactor of Example 1 was used to carry out the catalytic cracking reaction of crude oil.

[0122] Raw material: Daqing crude oil

[0123] Reaction conditions: The reaction temperature in the lower part of the dense phase conveying reaction section is 700℃, the reaction temperature in the upper part is 700℃, the reaction temperature at the top outlet of the riser is 690℃, the residence time in the annular reaction zone is 0.3s, the mass ratio of dilution gas to raw material is 0.3, the porosity of the sidewall of the lower diameter-changing section of the riser is 70%, the diameter ratio of the lower section of the riser to the dense phase conveying reaction section is 0.5:1, and the ratio of the length of the lower diameter-changing section of the riser to the total length of the dense phase conveying reaction section is 0.6:1. The composition of the products after the reaction is shown in the table below (each substance's content is a mass percentage).

[0124] Example 5

[0125] Raw material: Daqing crude oil

[0126] Reaction conditions: The reaction temperature in the lower part of the dense-phase bed reactor was 690℃, the reaction temperature in the upper part was 690℃, the reaction temperature at the top outlet of the riser was 680℃, the residence time in the dense-phase bed reactor was 0.3s, the mass ratio of dilution gas to feedstock was 0.4, the opening rate of the sidewall of the variable-diameter section of the lower riser was 60%, the diameter ratio of the lower riser section to the dense-phase conveying reaction section was 0.5:1, and the ratio of the length of the variable-diameter section of the lower riser section to the total length of the dense-phase conveying reaction section was 0.8:1. The composition of the products after the reaction is shown in the table below (each substance's content is a mass percentage).

[0127] Composition of Daqing crude oil

[0128]

[0129]

[0130] Comparison of different implementation schemes

[0131]

[0132] Comparative Example 1

[0133] Raw material: Daqing crude oil

[0134] Reaction conditions: reaction temperature at the bottom of the riser is 750℃, reaction temperature at the outlet of the riser is 700℃, residence time is 0.3s, and the mass ratio of dilution gas to raw material is 0.3.

[0135] Reactor: Conventional straight-tube reactor, such as Figure 4 The straight-tube riser reactor 12.

[0136] Comparative Example 2

[0137] The comparative example differs from Example 3 in all process conditions except for the configuration of the cyclone separator in the reactor settling tank. Instead of the primary separator described in this application, a conventional two-stage cyclone separator is used: a primary cyclone separator and an inlet top cyclone separator. The riser outlet is connected to the primary cyclone separator, and the primary cyclone separator outlet is connected to the top cyclone separator inlet. The gas-solid separation process involves high-temperature oil and gas, along with the catalyst, directly entering the primary cyclone separator. After entering the top cyclone separator, the oil and gas enter the gas collection chamber and are transported via oil and gas pipelines to the bottom of the fractionation tower for fractionation. The separated catalyst is discharged from the wing valves at the bottom of the primary and top cyclone separators, reaches the bottom of the settling tank, and enters the regenerator for coking via the waiting inclined pipe.

[0138] The reactor configuration using this comparative settling device differs from other reaction conditions described in Example 3, except that the mass ratio of catalyst to feed oil reaches 10. After the reaction, the catalyst is separated by the settling device, and the catalyst loss reaches 10%.

Claims

1. A feedstock oil catalytic cracking reactor, comprising: The reactor and the settling tank located above the reactor, wherein the lower section of the riser extends into the reactor through the bottom of the reactor, and the lower section of the riser inside the reactor includes a variable diameter section, the cross-section of which gradually increases from top to bottom, and multiple openings are provided on the wall of the variable diameter section of the lower section of the riser. One end of the lower section of the riser inside the reactor is open, and the lower section of the riser below the variable diameter section is connected to the regenerant inclined tube. The primary separator and the cyclone separator are located inside the settling tank of the settling tank. The primary separator includes a bend and a feed pipe connected to the bend. In the longitudinal section of the bend, the lower edge of the bend is connected to the upper end of the feed pipe. The first end of the bend is connected to the outlet on the side wall of the reactor, and the second end of the bend is connected to the cyclone separator. The bend bends upward from the connection point with the side wall of the reactor.

2. The reaction apparatus according to claim 1, characterized in that, The reducing section of the lower section of the riser is frustum-shaped, and in the axial direction, the angle between the pipe wall of the reducing section and the axis is 1-88 degrees. o .

3. The reaction apparatus according to claim 2, characterized in that, The angle between the pipe wall and the axis of the reducing section is 2-30 degrees. o .

4. The reaction apparatus according to claim 1, characterized in that, At least two openings shall be provided on the same cross-section of the pipe wall in the variable diameter section, and they shall be evenly distributed.

5. The reaction apparatus according to claim 4, characterized in that, In the axial direction, openings are provided on at least two cross sections of the pipe wall of the variable diameter section.

6. The reaction apparatus according to claim 4 or 5, characterized in that, On the pipe wall of the reducing section, the total area of ​​the openings accounts for 10-80% of the total area of ​​the reducing section in the lower part of the riser.

7. The reaction apparatus according to claim 1 or 2, characterized in that, The reactor includes an interconnected dense phase conveyed bed reaction section and a riser. The dense phase conveyed bed reaction section is located below the riser, and the lower section of the riser extends into the dense phase conveyed bed reaction section through the bottom of the reactor.

8. The reaction apparatus according to claim 7, characterized in that, The ratio of the length of the lower section of the riser pipe in the reaction section of the dense phase conveying bed to the total length of the reaction section of the dense phase conveying bed is (0.2-0.8):

1.

9. The reaction apparatus according to claim 7, characterized in that, The ratio of the length of the lower section of the riser pipe in the reaction section of the dense phase conveying bed to the total length of the reaction section of the dense phase conveying bed is (0.3-0.6):

1.

10. The reaction apparatus according to claim 7, characterized in that, The diameter ratio of the riser and the dense phase conveying bed reaction section of the reactor is (0.1-0.8):

1.

11. The reaction apparatus according to claim 7, characterized in that, The diameter ratio of the riser and the dense phase conveying bed reaction section of the reactor is 0.2-0.8:

1.

12. The reaction apparatus according to claim 7, characterized in that, A gas distributor is installed in the annular reaction zone between the lower section of the riser and the dense phase conveying bed reaction section to distribute the dilution medium; The feedstock oil is introduced into the annular reaction zone between the lower section of the riser and the reaction section of the dense phase conveying bed.

13. The reaction apparatus according to claim 12, characterized in that, The feedstock oil is injected into the annular reaction zone above the gas distributor in the dense phase conveying bed.

14. The reaction apparatus according to any one of claims 1-5, characterized in that, The feed pipe of the primary separator includes a feed pipe air lift section and a feed pipe conveying section.

15. The reaction apparatus according to any one of claims 1-5, characterized in that, The bend in the primary separator includes a smoothly transitioning curved section; from the first end to the second end of the bend, relative to the central axis of the reactor, the curved section first extends away from the central axis and then extends closer to the central axis.

16. The reaction apparatus according to claim 15, characterized in that, In the longitudinal section of the curved section, the side closest to the central axis of the reactor is arc-shaped; the central angle of the arc is 120°~240°.

17. The reaction apparatus according to any one of claims 1-5, characterized in that, The lower edge of the bend between the first end of the bend and the feed pipe is arc-shaped, and the central angle of the arc is between 0 and 90 degrees. o And the central angle of the arc is not 0. o .

18. The reaction apparatus according to claim 17, characterized in that, The central angle of the arc is 5-80 degrees. o .

19. The reaction apparatus according to any one of claims 1-5, characterized in that, From the first end to the second end of the bend, the cross-section of the bend first increases and then decreases.

20. The reaction apparatus according to claim 19, characterized in that, The reactor is a riser reactor, and the ratio of the cross-sectional diameter of the primary separator bend to the riser diameter is (1-5):

1.

21. The reaction apparatus according to claim 20, characterized in that, The ratio of the cross-sectional diameter of the primary separator bend to the diameter of the riser pipe is (1-3):

1.

22. A method for catalytic cracking of crude oil using the reaction apparatus of claim 12, characterized in that, The reaction temperature in the annular reaction zone is controlled at 400-800℃; the residence time in the annular reaction zone is controlled at 0.1-5 s; and the agent-to-oil ratio is controlled at 5-60.

23. The method according to claim 22, characterized in that, The reaction temperature in the annular reaction zone is controlled at 500-750℃; The residence time in the annular reaction zone is controlled to be 0.2-3 seconds.

24. The method according to claim 22, characterized in that, The residence time of the entire reactor is controlled between 1 and 8 seconds.

25. The method according to claim 22, characterized in that, The residence time of the entire reactor is controlled between 2 and 7 seconds.

26. The method according to claim 22, characterized in that, The reactor includes an interconnected dense phase conveying bed reaction section and a riser. The dense phase conveying bed reaction section is located below the riser. The outlet gas velocity of the opening in the pipe wall of the variable diameter section of the lower part of the riser in the dense phase conveying bed reaction section is 0.1-20 m / s.

27. The method according to claim 22, characterized in that, The outlet gas velocity of the opening in the pipe wall of the variable diameter section of the lower section of the riser in the reaction section of the dense phase conveying bed is 1-10 m / s.

28. The method according to claim 22, characterized in that, The average linear velocity of the catalyst at the upper outlet of the lower section of the riser is 0.2-20 m / s.

29. The method according to claim 22, characterized in that, The average linear velocity of the catalyst at the upper outlet of the lower section of the riser is 1-15 m / s.

30. The method according to claim 22, characterized in that, The average linear velocity at the outlet of the reaction section of the dense phase conveying bed is controlled at 1-20 m / s.

31. The method according to claim 22, characterized in that, The average linear velocity at the outlet of the reaction section of the dense phase conveying bed is controlled at 3-15 m / s.

32. The method according to claim 22, characterized in that, The distance between the dilution medium distribution pipe and the raw material nozzle is 0.1-30m.

33. The method according to claim 22, characterized in that, The distance between the dilution medium distribution pipe and the raw material nozzle is 0.5-10m.

34. The method according to claim 22, characterized in that, The mass ratio between the dilution medium and the raw material is 0.1-0.7:

1.

35. The method according to claim 22, characterized in that, The mass ratio between the dilution medium and the raw material is 0.1-0.6:

1.

36. The application of the reaction apparatus according to any one of claims 1-5 in the catalytic cracking reaction of hydrocarbons; The hydrocarbons mentioned include one or a mixture of several of crude oil, wax oil, heavy oil, gasoline, naphtha, and diesel.

Images