A downflow reaction system and method for catalytic cracking

Abstract

This application provides a catalytic cracking downflow bed reactor system and method, including a downflow bed reactor and a rapid separation device located at the outlet of the downflow bed reactor. The downflow bed reactor includes a recirculating cylinder, a straight cylinder, and a booster. The inlet of the straight cylinder is located inside the recirculating cylinder for receiving catalyst output from the recirculating cylinder, and the outlet of the straight cylinder is located outside the recirculating cylinder for outputting the catalyst and oil / gas after catalytic cracking within the straight cylinder. The outlet of the booster extends through the top of the recirculating cylinder to the inlet of the straight cylinder. The booster is configured to input a booster gas flow to propel the catalyst from the recirculating cylinder to the straight cylinder. The system provided by this invention achieves high-throughput operation of catalyst particles within the downflow bed, increasing the production capacity of the downflow bed reactor system.

Description

Technical Field

[0001] This application relates to the field of oil refining equipment, and in particular to a catalytic cracking downflow reaction system and method. Background Technology

[0002] The efficient conversion and optimized utilization of heavy oil is a crucial foundation for national economic development, possessing significant practical and strategic importance. Riser catalytic cracking has long been an important means of lightening heavy oil, but the non-uniform ring-core structure and gas-solid backmixing characteristics of riser reactors reduce heavy oil conversion rates and product selectivity. Compared to riser reactors, downflow bed reactors offer advantages such as near-plug flow pattern and low gas-solid backmixing, providing potential advantages in oil refining processes.

[0003] However, the widely used downflow bed reactors have limitations due to their structure, resulting in a low concentration of catalyst particles in the bed. This makes it difficult to achieve high catalyst circulation flux, leading to a decrease in light oil production. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a descending bed reaction system and method for catalytic cracking, which achieves high-throughput operation of catalyst particles within the descending bed and improves the production capacity of the descending bed reaction system.

[0005] The first aspect of this invention provides a downflow reaction system for catalytic cracking, the technical solution of which is:

[0006] A catalytic cracking downflow reactor system includes a downflow reactor and a rapid separation device located at the outlet of the downflow reactor. The downflow reactor includes a recirculation cylinder, a straight cylinder, and a booster.

[0007] The inlet of the straight cylinder is located inside the folding cylinder and is used to receive the catalyst output from the folding cylinder. The outlet of the straight cylinder is located outside the folding cylinder and is used to output the catalyst and oil and gas after catalytic cracking reaction inside the straight cylinder.

[0008] The outlet of the booster extends through the top of the deflector to the inlet of the straight cylinder; wherein the booster is configured to input a booster gas flow to drive the catalyst from inside the deflector into the straight cylinder.

[0009] As one preferred embodiment, the return tube is provided with a catalyst inlet and an oil / gas inlet, respectively, and the return tube is used to simultaneously receive the catalyst and the oil / gas; wherein...

[0010] A jet zone is formed inside the deflection tube, and the jet zone corresponds to the area above the inlet of the straight cylinder.

[0011] The straight cylinder is used to receive the catalyst and oil and gas output from the return cylinder for catalytic cracking reaction.

[0012] As a preferred embodiment, the return cylinder is provided with a catalyst inlet, and the straight cylinder is provided with an oil and gas inlet; the return cylinder is used to receive the catalyst separately.

[0013] An overflow zone is formed inside the folding cylinder, and the overflow zone corresponds to the area above the inlet of the straight cylinder.

[0014] The straight cylinder is used to receive the catalyst output from the return cylinder and the oil and gas input from its own oil and gas inlet for catalytic cracking reaction.

[0015] As one preferred embodiment, the oil and gas inlet is connected to a gas nozzle that extends obliquely upwards or downwards along one side of the deflector cylinder; or...

[0016] The oil and gas inlet is connected to a gas nozzle that extends obliquely upward or downward along one side of the straight cylinder.

[0017] As one of the preferred options, a steam loosening straight pipe and a duct-type rectifier are sequentially arranged inside the straight cylinder from the inlet to the outlet.

[0018] As one of the preferred options, a conical baffle is provided inside the straight cylinder, and the conical baffle is located below the oil and gas inlet.

[0019] As a preferred embodiment, a flow-rectifying baffle ring is provided in the straight cylinder body near the outlet.

[0020] As one of the preferred embodiments, the return cylinder is provided with a fluidizing steam inlet, which is configured to introduce fluidizing steam, and an air distribution plate is provided inside the return cylinder above the fluidizing steam inlet.

[0021] As one preferred embodiment, the rapid separation device includes a separator body and a central cylinder. The separator body has a mixture inlet and a catalyst outlet on its two sides, respectively. The central cylinder is partially inserted into the separator body, and an oil / gas outlet is located at the end of the central cylinder extending outside the separator body.

[0022] At least one air guide groove is provided on the inner wall surface of the central cylinder.

[0023] A second aspect of the present invention also provides a method for carrying out catalytic cracking reactions relying on a catalytic cracking downbed reaction system as provided in the first aspect of the present invention.

[0024] Compared with the prior art, this application has the following advantages:

[0025] This invention provides a catalytic cracking downflow reactor system, comprising a downflow reactor and a rapid separation device located at the outlet of the downflow reactor. The downflow reactor includes a recirculating cylinder, a straight cylinder, and a booster. The inlet of the straight cylinder is located inside the recirculating cylinder and is used to receive the catalyst output from the recirculating cylinder. The outlet of the straight cylinder is located outside the recirculating cylinder and is used to output the catalyst and oil / gas after the catalytic cracking reaction within the straight cylinder. The outlet of the booster extends through the top of the recirculating cylinder to the inlet of the straight cylinder. The booster is configured to input a booster gas flow to propel the catalyst from the recirculating cylinder to the straight cylinder.

[0026] By adopting the technical solution of this application, the recirculating cylinder, as the inlet component of the downward-flowing bed reactor, can at least introduce the catalyst, while the straight cylinder, as the main component of the downward-flowing bed reactor where the catalytic cracking reaction occurs, establishes the environment for the catalyst and oil and gas to carry out the catalytic cracking reaction and can organize and control the degree of catalytic cracking reaction. The rapid separation device, as the outlet structure of the downward-flowing bed reaction system, can realize the rapid separation of catalyst particles and oil and gas products, terminating the catalytic cracking reaction. Furthermore, a booster extending into the straight cylinder is installed inside the recirculating cylinder. The booster gas flow input by the booster can enhance the fluidity and velocity of the catalyst in the downward-flowing bed reactor, thereby avoiding stagnation and blockage caused by catalyst particles colliding and accumulating at the inlet of the straight cylinder. Therefore, it increases the catalyst circulation flux, improves the efficiency of the catalytic cracking reaction, and increases the yield of light products.

[0027] The methods described in this embodiment of the invention have the same advantages over the prior art as the systems described above, and will not be repeated here. Attached Figure Description

[0028] To more clearly illustrate the technical solution of this application, the drawings used in the description of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the structural principle of a descending bed reactor according to an embodiment of this application;

[0030] Figure 2 This is a schematic diagram of the overall structure of the straight cylinder according to an embodiment of this application;

[0031] Figure 3 This is a schematic diagram of the structural principle of a descending bed reactor according to another embodiment of this application;

[0032] Figure 4This is a schematic diagram of the overall structure of the straight cylinder according to another embodiment of this application;

[0033] Figure 5 This is a front view structural schematic diagram of the fast separation device according to another embodiment of this application;

[0034] Figure 6 This is a top view of the fast separation device according to another embodiment of this application;

[0035] Figure 7 This is a flow path diagram of the catalyst and oil and gas described in another embodiment of this application;

[0036] Figure 8 This is yet another flow path diagram of the catalyst and oil and gas described in another embodiment of this application.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1. Reversing cylinder; 2. Straight cylinder body; 3. Oil and gas inlet; 4. Catalyst inlet; 5. Rectifying baffle ring; 6. Duct-type rectifier; 7. Steam loosening straight pipe; 8. Conical rectifier baffle; 9. Rectifier internal structure insert; 10. Booster; 11. Air distribution plate; 12. Fluidized steam inlet; 13. Separator body; 131. Mixed material inlet; 132. Catalyst outlet; 133. Oil and gas outlet; 14. Central cylinder; 141. Gas guide groove. Detailed Implementation

[0039] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0040] It should be noted that a downflow bed reactor is a reactor in which both gas and solids move downwards simultaneously. Compared with other fluidized bed reactors (such as bubbling beds, turbulent beds, and risers), it possesses characteristics such as plug flow reactor performance and the absence of gas-solid backmixing. In recent years, downflow bed reactors have been considered a novel type of multiphase flow reactor with great application potential in high-intensity operations such as high-temperature, ultra-short contact time reactions.

[0041] A multi-stage countercurrent catalytic cracking / pyrolysis system and method have been proposed by relevant technicians, in which a representative downflow bed reactor is used to construct the catalytic cracking / pyrolysis reaction environment. However, this downflow bed reactor has at least the following shortcomings:

[0042] 1. In existing downward flow bed reactors, catalyst particles need to collide above the straight cylinder in the downward flow bed, reduce their velocity to zero, and then accelerate in the opposite direction. This makes it easy for catalyst particles to become clogged at the inlet of the straight cylinder, making it difficult to further increase the catalyst circulation flux, reduce the oil-to-catalyst ratio, weaken the reaction efficiency, and reduce the yield of light products.

[0043] 2. In the straight cylinder of the downward flow bed reactor, the catalyst particles tend to form concentrated rings near the wall, resulting in uneven distribution of catalyst particles in the bed and low oil-agent contact efficiency, which further reduces the yield and quality of light products.

[0044] 3. During degassing, the oil and gas in the horizontal fast separator at the outlet of the downflow bed reactor enter the central cylinder 14 through the gap near the side of the cylinder. The oil and gas pressure is high and the gas velocity is fast, which causes the oil and gas to carry a large number of catalyst particles out, resulting in incomplete degassing and a decrease in fast separation efficiency. This needs to be further improved to meet the ultra-high requirements for efficient gas-solid separation in the catalytic reaction process.

[0045] The main technical content of the present invention will be described in detail below with reference to several embodiments. Among them, the embodiment of the deflector tube 1 with a jet zone described below can be combined with... Figure 1 , Figure 2 and Figure 8 The technical solution of the present invention will be clearly and thoroughly explained. The embodiment of the return cylinder 1 with an overflow zone can be combined with... Figure 3 , Figure 4 and Figure 7 The technical solution of this invention will be clearly and thoroughly explained; embodiments of the fast separation device can be combined with... Figure 5 and Figure 6 The technical solution of this invention is clearly and thoroughly explained. Although the embodiment omitting the booster 10 is not shown separately, its main structure can still be referred to in the accompanying drawings of other embodiments. Figures 1-8 The black arrows represent the flow paths of oil and gas, while the white arrows represent the flow paths of the catalyst.

[0046] The main objective of this invention is to solve the problem of high-throughput operation of current catalysts. This invention provides a descending bed catalytic cracking reaction system, including a descending bed reactor and a rapid separation device located at the outlet of the descending bed reactor. The descending bed reactor includes a recirculating cylinder 1, a straight cylinder 2, and a booster 10. The inlet of the straight cylinder 2 is located inside the recirculating cylinder 1, for receiving the catalyst output from the recirculating cylinder 1. The outlet of the straight cylinder 2 is located outside the recirculating cylinder 1, for outputting the catalyst and oil / gas after the catalytic cracking reaction within the straight cylinder 2. The outlet of the booster 10 extends through the top of the recirculating cylinder 1 to the inlet of the straight cylinder 2. The booster 10 is configured to input a booster gas flow to propel the catalyst from the recirculating cylinder 1 to the straight cylinder 2.

[0047] Specifically, you can refer to Figures 1-4 , Figure 1 An exemplary downward-flowing bed reactor according to some embodiments of this disclosure is shown; Figure 2 It shows Figure 1 The straight cylindrical body 2 inside the descending bed reactor shown; Figure 2 An exemplary downward-flowing bed reactor according to some embodiments of this disclosure is shown; Figure 4 It shows Figure 3 The straight cylindrical body 2 shown is inside the downward-flowing bed reactor. The return cylinder 1 can be understood as the inlet component of the downward-flowing bed reactor. It can be bullet-shaped or M-shaped to receive catalyst and / or oil and gas. The catalyst and / or oil and gas can flow around the space inside the return cylinder 1 to prepare for the subsequent catalytic cracking reaction.

[0048] The straight cylinder 2 can be understood as the main component of the downward-flowing bed reactor where the catalytic cracking reaction takes place. The catalyst and oil / gas undergo catalytic cracking within the cylinder, producing light hydrocarbon products. The catalyst and oil / gas after the catalytic cracking reaction are output through the outlet of the straight cylinder 2. The straight cylinder 2 can be partially embedded within the return cylinder 1, with the remaining portion extending outside the return cylinder 1. Specifically, the straight cylinder 2 extends vertically from the top to the bottom of the return cylinder 1, penetrating the bottom and extending a certain distance beyond the bottom, and is separated from the top of the return cylinder 1. The end of the straight cylinder 2 near the top of the return cylinder 1 serves as the inlet. The catalyst initially flows around the perimeter of the return cylinder 1, colliding with the space between the inlet of the straight cylinder 2 and the top wall of the return cylinder 1, and then flows in the opposite direction into the straight cylinder 2. The end of the straight cylinder 2 near the top of the return cylinder 1 serves as the outlet to discharge the catalyst and oil / gas.

[0049] During the flow of the catalyst towards the straight cylinder 2, this invention innovatively introduces a booster 10. The booster 10 can be understood as a pipe structure forming a gas velocity flow space. Part of it is embedded within the deflector cylinder 1 and located at the inlet of the straight cylinder 2, allowing the gas outlet of the booster 10 to communicate with the inlet of the straight cylinder 2. The remaining part extends a distance from the top of the deflector cylinder 1, with its end serving as a gas inlet. Since catalyst particles easily accumulate at the inlet of the descending bed, the booster 10 delivers a boosting gas flow. This boosting gas flow flows downwards along the internal space of the booster 10 to the inlet of the straight cylinder 2. The boosting gas flow possesses kinetic energy, generating thrust. This not only breaks up the accumulation of catalyst particles but also pushes the accumulated catalyst particles downwards from the inlet of the straight cylinder 2 into the straight cylinder 2, increasing the driving force of the catalyst flow within the bed, promoting the flow between catalyst particles, enhancing the catalyst's fluidity and flow rate, and making it less prone to stagnation and blockage within the straight cylinder 2, thus achieving high-throughput operation of the catalyst particles.

[0050] In some embodiments, the airflow outlet of the booster 10 can extend a certain distance into the interior of the cylindrical body 2.

[0051] In some embodiments, the outlet of the straight cylinder 2 is connected to a rapid separation device, which can be understood as the outlet structure of a downward bed reactor system, used for the rapid separation of catalyst particles and oil and gas products to terminate the catalytic cracking reaction.

[0052] In some embodiments, the return cylinder 1 can receive both catalyst and oil / gas, and output them together into the straight cylinder 2. The oil / gas can be feedstock oil or an oil / gas mixture that has undergone a certain degree of reaction. In some embodiments, the oil / gas in the straight cylinder 2 can be received through its own oil / gas inlet 3 without being transported through the return cylinder 1. The oil / gas can preferably be an oil / gas mixture.

[0053] It is understandable that staff can adjust the flow rate and speed of the booster airflow to regulate the smooth and rapid high-flux flow of catalyst particles in the descending bed.

[0054] As a further explanation of this embodiment, the booster gas flow can be oil and gas, with the gas flow inlet of the booster 10 connected to an oil and gas storage device, such as a feedstock oil delivery branch pipe or a gas phase outlet of a fast separation unit in a multi-stage countercurrent catalytic cracking reaction system, i.e., a small portion of the oil and gas as reactants is used as the booster gas flow. Optionally, the booster gas flow can be accelerating steam, with the gas flow inlet of the booster 10 connected to a steam generating device, such as a boiler.

[0055] Thus, the downflow bed reaction system, composed of the return cylinder 1, the straight cylinder 2, the booster 10, and the fast separation device, works synergistically to achieve the flow, reaction, and separation of catalyst and oil and gas during the catalytic cracking reaction. This improves reaction efficiency, makes it suitable for catalytic cracking processes, and enhances production efficiency, reaction selectivity, and system flexibility. At the same time, it can reduce catalyst loss and consumption. Catalytic cracking processes equipped with the downflow bed reaction system of this embodiment are expected to become an important means in industrial catalytic reactions.

[0056] Please refer to it again. Figure 3 , Figure 4 and Figure 7 As mentioned above, the return cylinder 1 can receive both catalyst and oil / gas. In this embodiment, the return cylinder 1 is provided with a catalyst inlet 4 and an oil / gas inlet 3, and the return cylinder 1 is used to simultaneously receive catalyst and oil / gas. A jet zone is formed inside the return cylinder 1, and the jet zone corresponds to the area above the inlet of the straight cylinder 2. The straight cylinder 2 is used to receive the catalyst and oil / gas output from the return cylinder 1 for catalytic cracking reaction.

[0057] Specifically, catalyst inlet 4 can be defined as the introduction of catalyst, and oil and gas inlet 3 can be defined as the introduction of oil and gas. The catalyst and oil and gas enter the return cylinder 1 through catalyst inlet 4 and oil and gas inlet 3, and flow towards the top wall of the cylinder along its perimeter. Catalyst inlet 4 is located in the lower middle part of return cylinder 1, and oil and gas inlet 3 is located in the upper middle part of return cylinder 1. The catalyst and oil and gas mix at high speed in the gap between the inlet of the straight cylinder 2 and the top wall of return cylinder 1, forming a jet zone. The jet zone can be understood as the region where the catalyst and oil and gas interact, where the catalyst mixes with the oil and gas and forms a gas-solid two-phase flow. During the flow process, the catalyst and oil and gas are effectively mixed, thereby promoting the catalytic cracking reaction.

[0058] Next, the gas-solid mixture flows in the opposite direction to the outlet inside the straight cylinder 2, and the oil and gas are fully mixed with the catalyst particles. The particles in the bed move in a near-horizontal flow. Inside the straight cylinder 2, the catalyst and oil and gas continue to react and decompose into small molecule light products.

[0059] In some embodiments, the oil and gas inlet 3 is slightly higher than the inlet position of the straight cylinder 2 inside the return cylinder 1; in some embodiments, there are multiple oil and gas inlets 3, which are evenly distributed around the periphery of the outer wall of the return cylinder 1; in some embodiments, the size of the catalyst inlet 4 is larger than the size of the oil and gas inlet 3.

[0060] Please refer to it again. Figure 1 , Figure 2 and Figure 8As mentioned above, the oil and gas in the straight cylinder 2 can be transported without passing through the return cylinder 1, and can be received through its own oil and gas inlet 3. In this embodiment, the return cylinder 1 is provided with a catalyst inlet 4, and the straight cylinder 2 is provided with an oil and gas inlet 3. The return cylinder 1 is used to receive the catalyst alone. An overflow zone is formed inside the return cylinder 1, and the overflow zone corresponds to the area above the inlet of the straight cylinder 2. The straight cylinder 2 is used to receive the catalyst output from the return cylinder 1 and the oil and gas input from its own oil and gas inlet 3 for catalytic cracking reaction.

[0061] Specifically, the catalyst enters the return cylinder 1 through catalyst inlet 4, while the oil and gas enter the straight cylinder 2 through oil and gas inlet 3. The catalyst first flows from the periphery to the top wall of the return cylinder 1, causing high-speed mixing of the catalyst in the gap between the inlet of the straight cylinder 2 and the top wall of the return cylinder 1, forming an overflow zone. This overflow zone can be understood as the area with the highest catalyst particle concentration, where the catalyst overflows from the return cylinder 1 and flows into the straight cylinder 2. The catalyst can then enter the straight cylinder 2 along the flow path inside the return cylinder 1, mixing with the oil and gas within the straight cylinder 2 to undergo catalytic cracking and decompose into small-molecule light products.

[0062] In this embodiment, there are multiple oil and gas inlets 3, which are evenly distributed around the periphery of the outer wall of the cylindrical body 2. In some embodiments, the oil and gas inlets 3 are located on the side wall of the cylindrical body 2 extending out of the return cylinder 1. In some embodiments, the oil and gas inlets 3 are located on the side wall of the cylindrical body 2 inside the return cylinder 1, and are lower than the catalyst inlet 4.

[0063] The deflector cylinder 1 is provided with a fluidizing steam inlet 12, which is configured to introduce fluidizing steam. An air distribution plate 11 is provided inside the deflector cylinder 1 above the fluidizing steam inlet 12.

[0064] The fluidizing steam inlet 12 can be connected to a fluidizing steam pipeline to input fluidizing steam into the return cylinder 1. The fluidizing steam allows the catalyst to flow smoothly within the return cylinder 1, promoting mixing within the catalyst bed and further preventing the sedimentation and accumulation of catalyst particles. Above the fluidizing steam inlet 12, an air distribution plate 11 is installed. This air distribution plate 11 is a device for controlling gas flow and distribution, featuring a mesh-like porous structure that allows the fluidizing steam to enter the return cylinder 1 uniformly through the mesh or openings, creating a uniform flow state within the return cylinder 1.

[0065] Thus, the setting of the air distribution plate 11 can effectively control the flow direction and speed of the fluidizing steam. The fluidizing steam in the deflector cylinder 1 with the jet zone can help the catalyst and oil and gas mix fully. The fluidizing steam in the deflector cylinder 1 with the overflow zone can ensure that the catalyst forms a fluidized state inside the deflector cylinder 1.

[0066] The fluidized steam inlet 12 can be located on the bottom wall of the return cylinder 1, and the air distribution plate 11 is located below the catalyst inlet 4.

[0067] In some embodiments, the amount of fluidizing steam required to be input into the deflector 1 with the jet zone can be greater than the amount of fluidizing steam required to be input into the deflector 1 with the overflow zone.

[0068] It is worth mentioning that the deflector 1 with a jet zone has a high degree of gas-solid mixing. The oil and gas input from the oil and gas inlet 3 can preferably be feedstock oil. Feedstock oil usually needs to have a greater degree of mixing with the catalyst, and feedstock oil that has not yet undergone catalytic cracking can participate more fully in the cracking reaction, enabling the rapid generation of light intermediate products from crude oil catalytic cracking. The deflector 1 with an overflow zone has a shorter gas-solid mixing time. The oil and gas input from the oil and gas inlet 3 can preferably be an oil and gas mixture. The oil and gas mixture usually contains small molecules after cracking, which can avoid secondary cracking or over-reaction and avoid the generation of unnecessary reaction products, thereby improving the yield of light intermediate products.

[0069] In an embodiment with a jet zone in the deflector 1, the oil / gas inlet 3 is connected to a gas nozzle that extends obliquely upwards or downwards along one side of the deflector 1. Alternatively,

[0070] In an embodiment of the deflector cylinder 1 with an overflow zone, the oil and gas inlet 3 is connected to a gas nozzle that extends obliquely upward or downward along one side of the straight cylinder 2.

[0071] Specifically, a gas nozzle refers to a nozzle connected to at least one side of the return cylinder 1 or the straight cylinder 2, communicating with an oil and gas inlet 3 opened on the side wall of the return cylinder 1 or the straight cylinder 2. The gas nozzle can extend in an upward or downward inclined direction to guide and transport oil and gas. Depending on the inclination direction of the gas nozzle, the angle and direction of the oil and gas entering the return cylinder 1 or the straight cylinder 2 can be controlled to meet different reaction requirements. The inclined gas nozzle can generate dynamic effects such as rotation or vortexes when the oil and gas enter the return cylinder 1 or the straight cylinder 2, increasing the contact area and mixing degree between the gas and catalyst particles, thereby promoting the catalytic cracking reaction. Of course, by adjusting the nozzle design and process parameters, such as the nozzle shape, size, and inclination angle, the input oil and gas speed and flow rate can be controlled to adapt to different catalytic cracking reaction conditions and product requirements, which will not be elaborated upon further in this paper.

[0072] In some embodiments, the gas nozzles located on the return cylinder 1 may be arranged in the same or different directions as the gas nozzles located on the straight cylinder 2. That is, the gas nozzles of both reactors are inclined upward or inclined downward, or the gas nozzles of one descending bed reactor are inclined upward and the gas nozzles of the other descending bed reactor are inclined downward.

[0073] In a preferred embodiment, the gas nozzle located on the return cylinder 1 extends downward at an angle outward from one side of the return cylinder 1, so that when the oil and gas are injected into the return cylinder 1 from the outside, they are injected towards the top wall of the return cylinder 1. Under the high-speed flow of the oil and gas at the nozzle outlet, they rapidly mix with the catalyst in the top area of ​​the return cylinder 1 to form a high-concentration, high-speed gas-solid mixing zone. This allows the catalyst and oil and gas to mix at high speed in the gap between the inlet of the straight cylinder 2 and the top wall of the return cylinder 1, forming a gas-solid mixed jet zone, increasing the degree of reaction between the catalyst and the oil and gas, so as to achieve a high degree of catalytic cracking reaction of the feedstock oil.

[0074] In a preferred embodiment, the gas nozzle located on the straight cylinder 2 extends upward at an angle outward along one side of the straight cylinder 2, so that when the oil and gas are injected into the straight cylinder 2 from the outside, they are injected towards the outlet direction of the straight cylinder 2, thus avoiding gas-solid back mixing in the reaction area.

[0075] Another objective of this application is to address the problem that in current downward-flowing bed reactors, catalyst particles in the straight cylinder tend to form concentrated rings near the wall, resulting in uneven distribution of catalyst particles within the bed, low oil-catalyst contact efficiency, and further reduced yield and quality of light products. This application proposes a technical solution:

[0076] The cylindrical body 2 is provided with a steam loosening straight pipe 7 and a duct-type rectifier 6 sequentially arranged from the inlet to the outlet. In this embodiment, the steam loosening straight pipe 7 can be several vertically extending pipes into which steam can be introduced. The steam fluid generates intense turbulence and vibration within the straight pipe, causing collisions and loosening between catalyst particles. This breaks up the catalyst particles from the denser sidewalls, further increasing the fluidity and velocity of the catalyst particles and promoting the uniform distribution of the catalyst within the cylindrical body 2, thereby improving the contact efficiency between the catalyst and the oil and gas. Furthermore, the duct-type rectifier 6 typically consists of a set of ducts with a specific structure, which can be a porous plate or a slender tube. This duct can guide the flow of the catalyst and the oil and gas, forming a more uniform flow pattern, avoiding confusion and cross-contamination of the oil and gas, and allowing the catalyst particles and the oil and gas to flow more orderly, thereby further improving the contact efficiency between the catalyst and the oil and gas.

[0077] It is worth mentioning that the steam loosening straight pipe 7 and the duct rectifier 6 are more suitable for the straight cylinder 2 where the inlet is a jet zone.

[0078] As an extension of this embodiment, the booster 10 can be omitted from the deflector 1 that forms the jet region (e.g., ...). Figure 3 (See illustration). The fluidity and uniformity of the catalyst are improved by using steam to loosen the straight pipe 7 and the duct rectifier 6 within the straight cylinder 2.

[0079] Furthermore, a rectifier baffle ring 5 is installed below the duct-type rectifier 6. The rectifier baffle ring 5 can be understood as an annular groove or annular wall, which can change the direction and velocity of gas flow, causing the gas to rotate and reflux around the rectifier baffle ring 5, thereby promoting gas-solid mixing and uniform distribution of the catalyst. Thus, after the catalyst and oil / gas inside the straight cylinder 2 are loosened, dispersed, and homogenized by the steam-loosened straight pipe 7 and the duct-type rectifier 6, they are rectified by the impact of the rectifier baffle ring 5, effectively avoiding catalyst accumulation and dead zones. Consequently, a near-horizontal plug flow of catalyst and oil / gas is formed within the straight cylinder 2 for mixing and operation.

[0080] In another technical solution, a conical baffle 8 is provided inside the cylindrical body 2, and the conical baffle 8 is located below the oil and gas inlet 3. In this embodiment, the conical baffle 8 is located below the oil and gas inlet 3 of the cylindrical body 2, and is usually conical or similar in shape. It can guide and rectify the oil and gas entering the cylindrical body 2, and adjust the contact time and mixing degree between the catalyst and the oil and gas. The gas-solid mixing time between the oil and gas entering the cylindrical body 2 and the catalyst, as mentioned above, is relatively short, which can adapt to the reaction environment of the oil and gas mixture. By setting the conical baffle 8, which is opposite to the flow direction of the oil and gas mixture, the flow path of the oil and gas mixture is blocked and changed, so that the oil and gas mixture will change direction and diffuse when passing through the conical baffle 8. The gas flow rate decreases, the residence time of the gas in the cylindrical body 2 is prolonged, and the contact and mixing between the catalyst particles and the gas are increased, so as to control the degree of reaction and improve the reaction efficiency.

[0081] It is worth mentioning that the conical baffle 8 is more suitable for the straight cylinder 2, where the inlet is an overflow zone.

[0082] Furthermore, a flow-rectifying baffle ring 5 is provided below the conical flow-rectifying baffle 8. In this embodiment, after the catalyst and oil-gas mixture inside the cylindrical body 2 are dispersed by the impact of the conical flow-rectifying baffle 8, they are rectified by the impact of the flow-rectifying baffle ring 5, thereby forming a near-horizontal plug flow in the cylindrical body 2 where the catalyst and oil-gas mixture mix and operate.

[0083] In some embodiments, a steam loosening straight pipe 7 and / or a duct-type rectifier 6 may be provided between the conical rectifier baffle 8 and the rectifier baffle ring 5. In some embodiments, the catalyst entering the straight cylinder 2 has high kinetic energy due to the action of the booster 10, and the gas-solid two-phase contact and mixing can be fully achieved through the conical rectifier baffle 8, eliminating the need for secondary rectification by providing the steam loosening straight pipe 7 and the duct-type rectifier 6. In some embodiments, other rectifier internal structure inserts 9 may be provided above the conical rectifier baffle 8.

[0084] It should be noted that for any aspects of the steam loosening straight pipe 7, duct rectifier 6, conical rectifier baffle 8, and other rectifier internal components 9 not described in detail in this invention, please refer to the prior art.

[0085] Rapid separation units are commonly used in chemical processes such as catalytic cracking and are essential equipment for catalytic cracking production enterprises. The oil and gas output from the outlet of a descending bed reactor needs to be rapidly and efficiently separated from the catalyst particles to avoid secondary reactions and improve product yield. Another objective of this application is to address the problem in current horizontal rapid separation units at the outlet of descending bed reactors where, during degassing, oil and gas enter the central cylinder 14 through a gap near the side of the cylinder. The high pressure and velocity of the oil and gas cause a large amount of catalyst particles to be carried out, resulting in incomplete degassing.

[0086] Please refer to it again. Figure 5 and Figure 6 , Figure 5 The main structure of an exemplary fast-resolution device according to some embodiments of the present disclosure is shown. Figure 6 It shows Figure 5 The top view of the fast separation device shown.

[0087] The rapid separation device proposed in this application includes a separator body 13 and a central cylinder 14. The separator body 13 has a mixture inlet 131 and a catalyst outlet 132 on both sides. The central cylinder 14 is partially inserted into the separator body 13, and the end of the central cylinder 14 extending out of the separator body 13 has an oil and gas outlet 133. The inner wall of the central cylinder 14 is provided with at least one gas guide groove 141.

[0088] Specifically, the separator body 13 is annular, with its mixture inlet 131 opening facing upwards and located on the upper side of the separator body, communicating with the outlet of the straight cylinder 2 to receive the gas-solid mixture discharged from the straight cylinder 2. The catalyst outlet 132 is located on the lower side of the separator body 13 and opens downwards to discharge the catalyst separated within the separator body 13 by the central cylinder 14. The inlet end of the central cylinder 14 is located within the pipe connecting the mixture inlet 131 and the catalyst outlet 132 of the separator body 13, receiving the oil, gas, and catalyst input from the mixture inlet 131, while the outlet end extends out of the separator body 13 to discharge the separated oil and gas.

[0089] Since the inner wall of the central cylinder 14 is provided with at least one gas guide groove 141, when the oil and gas carrying a large amount of catalyst flows in the central cylinder 14 along the gas pressure, it is guided and constrained by the gas guide groove 141, which reduces the gas velocity and pressure fluctuation of the oil and gas, thereby reducing the amount of gas carrying catalyst, which helps to improve the efficiency of the fast separation device, achieve better gas-solid separation effect, and improve the catalyst recovery rate.

[0090] Preferably, a plurality of gas guide grooves 141 are arranged at intervals along the periphery of the inner wall of the central cylinder 14. More preferably, a plurality of gas guide grooves 141 are spaced apart in the inner wall region of the central cylinder 14 facing the catalyst outlet 132.

[0091] Another aspect of the present invention is to provide a method for carrying out catalytic cracking reactions in a bed reaction system based on catalytic cracking as described above.

[0092] The above method embodiments are basically similar to the system embodiments, so the description is relatively simple. For relevant details, please refer to the description of the method embodiments.

[0093] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0094] It should also be noted that, in this document, the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention 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, and therefore should not be construed as a limitation of the invention. Furthermore, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations, nor should they be construed as indicating or implying relative importance. Moreover, the term "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements, but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device.

[0095] The foregoing has provided a detailed description of a catalytic cracking downflow reaction system and method provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are merely for the purpose of aiding understanding this application, and the content of this specification should not be construed as limiting this application. Furthermore, those skilled in the art will recognize that various modifications and variations in the specific implementation methods and application scope may occur based on this application. It is neither necessary nor possible to exhaustively list all possible implementation methods here, but any obvious changes or modifications derived therefrom are still within the protection scope of this application.

Claims

1. A descending bed reaction system for catalytic cracking, characterized in that, The reactor includes a descending bed reactor and a rapid separation device located at the outlet of the descending bed reactor. The descending bed reactor includes a recirculation cylinder, a straight cylinder, and a booster. The inlet of the straight cylinder is located inside the folding cylinder and is used to receive the catalyst output from the folding cylinder. The outlet of the straight cylinder is located outside the folding cylinder and is used to output the catalyst and oil and gas after catalytic cracking reaction inside the straight cylinder. The booster outlet extends through the top of the deflector to the inlet of the straight cylinder; wherein the booster is configured to input a booster gas flow to drive the catalyst from inside the deflector into the straight cylinder; The reflux cylinder is equipped with a catalyst inlet and an oil / gas inlet, respectively, and is used to simultaneously receive both catalyst and oil / gas; wherein... A jet zone is formed inside the deflection tube, and the jet zone corresponds to the area above the inlet of the straight cylinder. The straight cylinder is used to receive the catalyst and oil and gas output from the return cylinder for catalytic cracking reaction; a steam loosening straight pipe and a duct rectifier are sequentially arranged in the straight cylinder from the inlet to the outlet.

2. A downflow reaction system for catalytic cracking, characterized in that, The reactor includes a descending bed reactor and a rapid separation device located at the outlet of the descending bed reactor. The descending bed reactor includes a recirculation cylinder, a straight cylinder, and a booster. The inlet of the straight cylinder is located inside the folding cylinder and is used to receive the catalyst output from the folding cylinder. The outlet of the straight cylinder is located outside the folding cylinder and is used to output the catalyst and oil and gas after catalytic cracking reaction inside the straight cylinder. The booster outlet extends through the top of the deflector to the inlet of the straight cylinder; wherein the booster is configured to input a booster gas flow to drive the catalyst from inside the deflector into the straight cylinder; The folding cylinder is equipped with a catalyst inlet, and the straight cylinder is equipped with an oil and gas inlet. The folding cylinder is used to receive the catalyst separately. An overflow zone is formed inside the folding cylinder, and the overflow zone corresponds to the area above the inlet of the straight cylinder. The straight cylinder is used to receive the catalyst output from the deflector cylinder and the oil and gas input from its own oil and gas inlet for catalytic cracking reaction; a conical rectifier baffle is provided inside the straight cylinder, and the conical rectifier baffle is located below the oil and gas inlet.

3. A catalytic cracking downflow reaction system according to claim 1 or 2, characterized in that, The oil and gas inlet is connected to a gas nozzle that extends obliquely upwards or downwards along one side of the deflector cylinder; or... The oil and gas inlet is connected to a gas nozzle that extends obliquely upward or downward along one side of the straight cylinder.

4. A catalytic cracking downflow reaction system according to claim 1 or 2, characterized in that, A flow-rectifying baffle ring is provided inside the straight cylinder near the outlet of the straight cylinder.

5. A catalytic cracking downflow reaction system according to claim 1 or 2, characterized in that, The deflector cylinder is provided with a fluidizing steam inlet, which is configured to introduce fluidizing steam. An air distribution plate is provided inside the deflector cylinder above the fluidizing steam inlet.

6. A catalytic cracking downflow reaction system according to claim 1 or 2, characterized in that, The rapid separation device includes a separator body and a central cylinder. The separator body has a mixture inlet and a catalyst outlet on both sides, respectively. The central cylinder is partially inserted into the separator body, and an oil / gas outlet is located at the end of the central cylinder extending outside the separator body. At least one air guide groove is provided on the inner wall surface of the central cylinder.

7. A method for carrying out catalytic cracking reaction relying on a catalytic cracking downbed reaction system as described in any one of claims 1-6.

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