Apparatus and method for catalytic cracking

Abstract

The invention relates to the technical field of catalysis, and discloses a catalytic cracking device and method. The device comprises a multi-stage reaction unit and a cracking reaction unit, the multi-stage reaction unit comprises a variable-diameter riser and a multi-stage reaction settler, and the cracking reaction unit comprises a cracking riser and a cracking settler; the variable-diameter lifting pipe comprises a first reaction zone, a second reaction zone and a third reaction zone which are sequentially connected in series in the length direction, the inner diameter of the second reaction zone is larger than that of the first reaction zone and that of the third reaction zone, and an inner conveying pipe extending into the second reaction zone is arranged at the joint of the third reaction zone and the second reaction zone; the cracking settler comprises a cracking steam stripping section, a turbulence reaction section and a cracking settling section which are sequentially arranged along the length direction of the cracking settler, an outlet of the cracking riser is positioned in the turbulence reaction section, and the cracking steam stripping section is provided with a cracking catalyst outlet communicated with the second reaction area. The device can improve the reaction efficiency of catalytic cracking of heavy oil and light hydrocarbon, and realizes tight coupling of heavy oil and light hydrocarbon.

Description

Technical Field

[0001] The present invention relates to the field of catalytic technology, and in particular to a device and method for catalytic cracking. Background Art

[0002] In the early catalytic cracking reaction, aluminum silicate beads were used as catalysts, and the reactor used a dense bed reactor; with the emergence of highly active and highly selective zeolite catalysts, the reaction rate of petroleum hydrocarbons and catalysts was greatly accelerated, and the reactor used a fast-transport bed riser, which was conducive to improving the yield and selectivity of liquid products. The riser reactor has made great progress in structure and operation compared with the dense bed reactor, mainly in the mixing of oil, gas and catalyst in the feed section, the rapid separation of the outlet product, the reduction of the temperature gradient on the riser cross section and the reduction of returns. Since the highly active zeolite catalyst greatly improves the reaction intensity, since the 1960s and 1970s, many companies have developed their own fast-transport bed reactors, namely riser reactors. Due to their good elasticity and flexibility, they emphasize the primary cracking of heavy oil, and the light oil yield and selectivity are relatively ideal. This type of reactor still has strong vitality. Since the end of the last century, the National III gasoline standard has begun to limit the olefin content of gasoline. CN1237477A, ​​CN1245202A, CN1232069A, etc. have proposed a variable diameter riser, adding a section of expansion in the middle of the riser to form a fluidized bed reaction section, which can further enhance the secondary reaction of the generated gasoline. Studies have found that this type of reactor can take into account the secondary conversion of gasoline while performing the primary cracking of heavy oil.

[0003] Initial variable diameter riser technology did not consider the need for internal components between the riser section and the fluidized bed section to adjust the gas-solid fluidization state. Since the size of the industrial device is meter-level, if there are no internal components, it is difficult to form a stable fluidization of the gas-solid fluid at the bottom of the expansion section due to factors such as the high-speed fluid jet from the lower riser entering the expansion section, and then form a stable solid particle dense phase area. Although in the industrial implementation of variable diameter risers, arched (convex) distribution plates, special-shaped (basin-shaped) distribution plates, concave distribution plates and mushroom-head distributors have been introduced successively, which can make the high-speed oil and gas and catalysts coming out of the riser form a fully uniform steady-state fluidization, and some catalysts form a stable fluidized bed; however, the expansion section of the riser is generally connected to the upper riser through a reduced diameter truncated cone-shaped outer cylinder, and no internal components are installed in this section to adjust the gas-solid fluidization.

[0004] In order to improve the quality of gasoline, reduce the olefin content of gasoline and increase the yield of cracked gas, a large number of technical measures for light hydrocarbon recycling have been disclosed at home and abroad. There are two typical methods: the first is to recycle gasoline or other light hydrocarbons to the original heavy oil riser, generally injected into the upstream of the feedstock oil nozzle. For example, US5043522A and US5846403A disclose injecting catalytic cracking gasoline into the upstream of the feedstock oil nozzle and using a high-temperature, high-activity regeneration catalyst to catalytically convert it; CN1160746A also discloses a method of injecting low-quality gasoline such as straight-run gasoline and coking gasoline into the lower part of the riser reaction to give priority to the reaction of the gasoline. The first method is to use a separate gasoline or light hydrocarbon riser for refining. For example, CN1069054A and US3784463A both use a double riser reactor to carry out the reaction, injecting low-quality gasoline including catalytic cracking crude gasoline into the gasoline riser reactor, and using high temperature and large agent-to-oil ratio reaction conditions to achieve catalytic modification of low-quality gasoline to increase the liquefied gas yield and gasoline octane number; the molecules generated after the light hydrocarbon feed contacts the catalyst are relatively small, and the volume expansion is obvious, which affects the heavy oil feed at the top of the catalytic cracking riser reactor and the contact between the heavy oil and the catalyst. Among them, the first method is to keep the heavy oil reaction from having a negative impact and the proportion of light hydrocarbon recycling is low; the second method is to add a separate light hydrocarbon riser on the basis of the traditional single riser reactor, so that the light hydrocarbons can undergo a secondary cracking reaction separately and the separate optimized reactions of different raw materials can be achieved. However, the traditional riser has poor control over the reaction depth. For example, if the riser outlet temperature is increased to achieve a higher conversion depth, over-cracking reaction is likely to occur; if the reaction temperature at the riser outlet is low, the ideal conversion depth cannot be achieved.

[0005] In addition, "A Brief Analysis of the Application of Catalytic Cracking DCC Double Riser Process" reported the device characteristics of the catalytic cracking DCC double riser process (i.e. DCC plus), the heavy oil reactor includes a riser and a turbulent bed, and the oil, gas and catalyst at the end of the light hydrocarbon riser are injected into the main settler; "Analysis of the Operation of Catalytic Cracking Units of the Combined Process of Heavy Oil MIP and Inferior Catalytic Cracking Diesel LTAG" disclosed the double reactor process of the combination of heavy oil MIP reactor and inferior catalytic cracking diesel LTAG reactor. However, there are still some defects such as the effect of the cracking reaction of heavy raw materials and light hydrocarbons is not ideal, and the product properties and product distribution are not easy to flexibly control. Summary of the invention

[0006] The object of the present invention is to provide a catalytic cracking device and method, which can enhance the gas-solid mixing and contact in the heavy oil cracking process and the light hydrocarbon cracking process, improve the catalytic reaction efficiency, realize the close coupling of the heavy oil reactor and the light hydrocarbon reactor, and improve the operational flexibility of regulating product properties and product distribution.

[0007] The inventors of the present invention unexpectedly discovered in the study of catalytic cracking that after coupling a heavy oil reactor using an expanded diameter riser in parallel with a light hydrocarbon cracking reactor, the catalyst after cracking the light hydrocarbons is recycled from the cracking catalyst outlet to the expanded diameter section of the heavy oil reactor, which not only allows the heavy oil cracking process and the light hydrocarbon cracking process to be carried out independently, thereby increasing the recycling ratio of light hydrocarbons, but also helps to strengthen the catalytic reaction of the heavy oil; by arranging an internal conveying pipe inside the expanded diameter section of the heavy oil reactor, the gas-solid fluidization state of the expanded diameter section can be changed and optimized, and the adjustment range of the gas linear velocity and the catalyst bed density in the expanded diameter section can be widened; and the turbulent reaction section is set in the cracking settler of the light hydrocarbon cracking reactor, which is also conducive to the fully enhanced contact between the light hydrocarbons and the cracking catalyst in the reaction section, and can achieve efficient contact reaction between the light hydrocarbons and the catalyst at a relatively low temperature and low space velocity, avoiding excessive cracking reaction of the light hydrocarbons caused by excessive reaction temperature; at this time, the coupling of the heavy oil reactor and the light hydrocarbon cracking reactor can simultaneously perform separate and efficient cracking / cracking operation control on the heavy oil and the light hydrocarbons, has more operating means, and can achieve various flexible operations for regulating product properties and product distribution.

[0008] In order to achieve the above-mentioned purpose, the first aspect of the present invention provides a catalytic cracking device, which includes a multi-stage reaction unit and a cracking reaction unit, the multi-stage reaction unit includes a multi-variable diameter riser and a multi-stage reaction settler, and the cracking reaction unit includes a cracking riser and a cracking settler; the multi-variable diameter riser includes a first reaction zone, a second reaction zone and a third reaction zone connected in series in sequence along its length direction, the outlet of the third reaction zone is connected to the multi-stage reaction settler, the inner diameter of the second reaction zone is larger than the inner diameters of the first reaction zone and the third reaction zone, and the connection between the third reaction zone and the second reaction zone is provided with an inner conveying pipe extending into the interior of the second reaction zone; the cracking settler includes a cracking stripping section, a turbulent reaction section and a cracking sedimentation section arranged in sequence along its length direction, the outlet of the cracking riser is located in the turbulent reaction section, and the cracking stripping section is provided with a cracking catalyst outlet connected to the second reaction zone.

[0009] Preferably, the ratio of the inner diameter of the inner transport pipe to that of the third reaction zone is 0.9-1.2:1, and the ratio of the length of the inner transport pipe to that of the second reaction zone is 0.15-0.8:1.

[0010] More preferably, the ratio of the inner diameters of the first reaction zone, the second reaction zone and the third reaction zone is 1:2-5:0.7-1.5, and the ratio of the lengths is 1:0.3-2:0.5-2; the ratio of the inner diameters of the turbulent reaction section, the cracking stripping section and the cracking sedimentation section is 1:0.4-0.8:2.5-5, and the ratio of the lengths is 1:1.5-3:1.5-4; the ratio of the lengths of the multi-variable riser to the cracking riser is 1:0.5-1.2.

[0011] Further preferably, at least one inner delivery hole is provided on the side wall of the inner delivery pipe, and the distance between the inner delivery hole and the entrance of the third reaction zone is 0.5-2 m.

[0012] Specifically, the ratio of the total area of ​​at least one of the inner delivery holes to the cross-sectional area of ​​the inner delivery tube is 0.05-0.3:1.

[0013] As a preferred embodiment, a distribution internal component connected to the first reaction zone is provided in the second reaction zone, and a plurality of distribution holes are provided on the distribution internal component.

[0014] Preferably, the distribution internal component includes a distribution cylinder connected to the first reaction zone and an end distribution plate connected to the distribution cylinder, the distribution cylinder and the end distribution plate are both provided with the distribution holes, and the end distribution plate is located at one end of the distribution cylinder away from the first reaction zone.

[0015] More preferably, the ratio of the sum of the areas of the distribution holes on the distribution cylinder to the cross-sectional area of ​​the first reaction zone is 0.6-4:1; the ratio of the sum of the areas of the distribution holes on the end distribution plate to the vertical projection area of ​​the end distribution plate is 0.1-0.3:1.

[0016] More preferably, a side channel extending toward the outside of the distribution tube is provided at the distribution holes on the distribution tube, and an opening section of the side channel away from the distribution tube is an inclined surface toward the first reaction zone.

[0017] Further preferably, the ratio of the area of ​​the end distribution plate to the cross-sectional area of ​​the second reaction zone is 0.7-0.85:1.

[0018] Specifically, the first reaction zone, the second reaction zone, the third reaction zone and the inner transport pipe are coaxially arranged, and the cracking catalyst outlet is located at the bottom of the cracking stripping section and is connected to the bottom of the second reaction zone.

[0019] More specifically, the multi-variable diameter riser also includes a multi-stage reaction pre-lifting section connected to the inlet of the first reaction zone, the cracking riser includes a cracking pre-lifting section and a cracking reaction section connected in series along its length direction, the outlet of the cracking reaction section is located at one end of the turbulent reaction section close to the cracking stripping section, the transition section between the multi-stage reaction pre-lifting section and the first reaction zone is connected to the multi-stage reaction feed unit, and the transition section between the cracking pre-lifting section and the cracking reaction section is connected to the cracking feed unit.

[0020] More specifically, a cracking distributor is provided at the outlet of the cracking reaction section, and the gas phase outlet of the cracking sedimentation section is connected to the multi-stage reaction settler.

[0021] Typically, the device also includes a regeneration unit, and the multistage reaction settler is provided with a multistage reaction catalyst outlet connected to the feed inlet of the regeneration unit, and the regeneration catalyst outlet of the regeneration unit is connected to the multi-variable riser and / or the cracking riser.

[0022] A second aspect of the present invention provides a method for catalytic cracking, using the above-mentioned device, the method comprising the following steps:

[0023] A multi-stage reaction mixture formed by mixing heavy raw materials and a multi-stage reaction catalyst is input from the inlet of the first reaction zone, enters the first reaction zone and the second reaction zone in sequence, and then enters the third reaction zone from the inner delivery pipe to perform a multi-stage catalytic reaction to obtain a multi-stage reactant. The multi-stage reactant is subjected to a multi-stage reaction separation in the multi-stage reaction settler to obtain a multi-stage reaction oil and gas product and a multi-stage reaction catalyst to be produced;

[0024] A cracking mixture formed by mixing a light raw material and a cracking catalyst is input from the inlet of the cracking riser, undergoes a cracking catalytic reaction through the cracking riser to obtain a cracking reactant, and after the cracking reactant enters the turbulent reaction section for a turbulent reaction, undergoes cracking separation through the cracking settling section, and undergoes cracking stripping through the cracking stripping section to obtain a cracking oil and gas product and a cracking catalyst to be produced;

[0025] The catalyst to be produced by cracking is introduced into the second reaction zone from the cracking catalyst outlet and mixed with the multi-stage reaction mixture.

[0026] Preferably, the inlet temperature of the inner transport pipe is 510-540°C, and the outlet temperature of the cracking riser is 540-620°C.

[0027] Preferably, the inlet temperature of the inner transport pipe is 550-640°C, and the outlet temperature of the cracking riser is 560-660°C.

[0028] More preferably, the residence time of the multi-stage reaction mixture in the first reaction zone is 0.8-2s, the residence time in the second reaction zone is 5-15s, and the residence time in the third reaction zone is 0.5-1.5s; the residence time of the cracking mixture in the cracking riser is 0.8-3.5s, and the residence time in the turbulent reaction section is 3-13s.

[0029] Through the above technical scheme, the catalytic cracking device provided by the present invention can independently carry out the heavy oil cracking process and the light hydrocarbon cracking process through the multi-stage reaction unit and the cracking reaction unit arranged in parallel, thereby increasing the recycling ratio of light hydrocarbons, and recycling the catalyst after the light hydrocarbon cracking from the cracking catalyst outlet to the second reaction zone, which helps to increase the flow rate and activity of the catalyst in the second reaction zone, strengthen the catalytic reaction of the heavy oil, and realize the close coupling of the heavy oil cracking process and the light hydrocarbon cracking process; by arranging the inner conveying pipe inside the multi-variable diameter riser of the multi-stage reaction unit, the gas-solid fluidization state of the second reaction zone can be changed and optimized, and the second reaction zone can be widened. The adjustment range of the gas linear velocity and the catalyst bed density is coordinated with the setting of a turbulent reaction section in the cracking settler of the cracking reaction unit. The cracking catalyst density of the turbulent reaction section is relatively large, which is conducive to the fully enhanced contact between the light hydrocarbons and the cracking catalyst in the reaction section, and can achieve efficient contact reaction between the light hydrocarbons and the catalyst at a relatively low temperature and low space velocity, avoiding excessive cracking reaction of the light hydrocarbons due to excessive reaction temperature; the coupling of the two reaction units in the device provided by the present invention can simultaneously perform separate cracking / cracking operation control on heavy oil and light hydrocarbons, and has more operating means to achieve various flexible operations for regulating product properties and product distribution.

[0030] Other advantages of the present invention and the technical effects of the preferred embodiments will be further described in the following specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0032] Figure 1 It is a structural schematic diagram of a specific implementation mode of the catalytic cracking device in the present invention;

[0033] Figure 2 It is a structural schematic diagram of a specific implementation mode of the internal delivery pipe and the distribution internal component in the present invention.

[0034] Description of Reference Numerals

[0035] 1-multi-stage reaction unit, 11-multi-variable riser, 11a-first reaction zone, 11b-second reaction zone, 11c-third reaction zone, 11d-multi-stage reaction pre-lifting section, 12-multi-stage reaction settler, 12a-multi-stage reaction stripping section, 12b-multi-stage reaction settling section, 12c-multi-stage reaction cyclone separator, 13-inner conveying pipe, 13a-inner conveying hole, 14-distribution internal component, 14a-distribution hole, 14b-distribution cylinder, 14c-end distribution plate, 14d-side channel, 15-multi-stage reaction catalyst outlet;

[0036] 2-cracking reaction unit, 21-cracking riser, 21a-cracking pre-lifting section, 21b-cracking reaction section, 22-cracking distributor, 23-cracking settler, 23a-cracking stripping section, 23b-turbulent reaction section, 23c-cracking settling section, 23d-cracking cyclone separator, 24-cracking gas phase conveying pipe, 25-cracking catalyst outlet;

[0037] 3-regeneration unit, 31-regeneration catalyst outlet, 32-regeneration cyclone separator, 33-regeneration air inlet, 34-regeneration flue gas outlet;

[0038] 4-catalyst heat collector; 5-pipeline to be regenerated; 6-regeneration pipeline; 7-multi-stage reaction feed unit; 8-cracking feed unit; 9-quenching oil and gas unit; 10-stripping steam unit;

[0039] A-multi-stage reaction pre-lifting gas; B-cracking pre-lifting gas; C-regeneration air; D-regeneration flue gas; E-reaction oil and gas; F-multi-stage reaction stripping steam; G-low-temperature water vapor; H-high-temperature water vapor. DETAILED DESCRIPTION

[0040] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0041] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connection" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, it can be abutment, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] It should be understood that the directions or positional relationships indicated by the terms "upper", "lower", "front", "back", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated, therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features.

[0043] In a basic embodiment of the present invention, see Figure 1The catalytic cracking device comprises a multistage reaction unit 1 and a cracking reaction unit 2, wherein the multistage reaction unit 1 comprises a multi-variable riser 11 and a multistage reaction settler 12, and the cracking reaction unit 2 comprises a cracking riser 21 and a cracking settler 23; the multi-variable riser 11 comprises a first reaction zone 11a, a second reaction zone 11b and a third reaction zone 11c which are sequentially connected in series along its length direction, the outlet of the third reaction zone 11c is connected to the multistage reaction settler 12, the inner diameter of the second reaction zone 11b is larger than that of the first reaction zone 11a, the outlet of the third reaction zone 11c is connected to the multistage reaction settler 12, the inner diameter of the second reaction zone 11b is larger than that of the first reaction zone 11c, and the outlet of the third reaction zone 11c is connected to the multistage reaction settler 12, and the inner diameter of the second reaction zone 11b is larger than that of the first reaction zone 11c. The inner diameter of the reaction zone 11a and the third reaction zone 11c, the connection between the third reaction zone 11c and the second reaction zone 11b is provided with an inner transport pipe 13 extending into the second reaction zone 11b; the cracking settler 23 includes a cracking stripping section 23a, a turbulent reaction section 23b and a cracking sedimentation section 23c arranged in sequence along its length direction, the outlet of the cracking riser 21 is located in the turbulent reaction section 23b, and the cracking stripping section 23a is provided with a cracking catalyst outlet 25 connected to the second reaction zone 11b.

[0044] The catalytic cracking device provided by the present invention can be applied to catalytic cracking or catalytic cracking processes in various chemical production fields, and is particularly suitable for catalytic cracking / catalytic cracking of heavy oil and light hydrocarbons, for example, producing ultra-low olefin gasoline and high-yield cracking gas; its reaction unit 1 is used as a heavy raw material (heavy oil) for catalytic cracking / catalytic cracking, and the cracking reaction unit 2 is used as a light raw material (light hydrocarbon) for catalytic cracking / catalytic cracking. It should be emphasized that the catalytic cracking device in the present application is based on the parallel arrangement of the multi-stage reaction unit 1 and the cracking reaction unit 2. By replacing the catalyst and adjusting the operating conditions, the switching of the two operating modes of ultra-low olefin gasoline and high-yield cracking gas can be achieved, and the adjustment depth and variation range of the two modes can be increased to achieve a processing volume with a larger proportion of light hydrocarbons relative to heavy oil; wherein, the light hydrocarbons can come from outside the multi-stage reaction unit 1 in the device and even outside the use workshop or factory. In addition, when the multistage reaction unit 1 and the cracking reaction unit 2 are connected in parallel, the catalyst after the cracking of the light hydrocarbons is recycled to the second reaction zone 11b from the cracking catalyst outlet 25, so that the high-temperature spent catalyst after the light hydrocarbon reaction has a high cracking activity and is supplemented to the second reaction zone 11b of the multistage reaction unit 1, thereby effectively improving the catalyst concentration and catalyst activity inside the second reaction zone 11b, and realizing the close coupling of the multistage reaction unit 1 and the cracking reaction unit 2.

[0045] The inventors found in the research process that if the superficial gas velocity in the expansion section of the conventional MIP-CGP reactor is too low, it is not enough to carry the catalyst to the third reaction zone 11c, which is prone to choking and even accumulation of catalyst in the expansion section, causing device accidents; if the superficial gas velocity is too high, the catalyst dense phase section cannot be formed in the expansion section, and the process requirements cannot be met. By setting an internal delivery pipe 13 in the second reaction zone 11b (i.e., the expansion section) with a larger inner diameter in the multi-variable riser 11, the above defects can be effectively overcome, and the following effects are produced: First, when the superficial gas velocity in the second reaction zone 11b is reduced to form a turbulent bed, when the upper interface of the turbulent bed submerges the bottom port of the internal delivery pipe 13, the catalyst on the top of the turbulent bed can be sucked away, and the height of the turbulent bed in the second reaction zone 11b can be controlled. Secondly, the upper part of the expanded diameter section at the upper part of the second reaction zone 11b, which is coaxial and at the same height as the inner conveying pipe 13, can be used as the dilute phase section of the turbulent bed. The gas carries a large amount of particulate solids and scatters them to the dilute phase section above the turbulent bed. As the gas flow rate decreases, a free space for the solid particles to settle is formed, and the catalyst particles entrained by the turbulent bed will fall into the lower part of the second reaction zone 11b again, thereby enhancing the back mixing of the catalyst. Since a considerable amount of gas is stored in the free space, a buffer space can be provided for the gas pulsation in the multi-variable riser 11. The above two effects can, to a certain extent, avoid the rapid increase and sharp fluctuation of a large amount of catalyst and gas pressure in the multi-variable riser 11, thereby widening the gas linear velocity range for optimal operation in the second reaction zone 11b. Third, the gas-solid fluidization in the second reaction zone 11b is a turbulent bed. At the bottom of the turbulent bed, the solid phase is violently turbulent and in a continuous phase. The solid-gas ratio per unit space is large, the bubble diameter of the solid particles in the turbulent bed is small, and the gas-solid contact efficiency is enhanced. Generally, the gas-solid contact efficiency is higher than that of various forms of conveying beds, and it is suitable for some fields that require further enhancement of the gas-solid contact efficiency. Fourth, if a gas velocity greater than 2m / s is used, since the gas velocity in the expanded diameter section at the same height as the inner conveying pipe 13 is small, the catalyst thrown up by the high-speed gas below can be made to land in the second reaction zone 11b at the bottom, thereby increasing the catalyst density at the bottom of the second reaction zone 11b and enhancing gas-solid mixing and contact.

[0046] Compared with the conventional MIP-CGP reactor, the inner delivery pipe 13 provided by the present invention changes the flow state of the gas and the catalyst in the second reaction zone 11b to a certain extent. The gas superficial velocity range in the second reaction zone 11b is wider. The superficial gas velocity of the conventional MIP-CGP expansion section is 1.4-2.8m / s, and the industrial operation device is generally preferably 1.5-2.0m / s; in the multi-stage reaction unit 1 provided by the present invention, the superficial gas velocity in the second reaction zone 11b can form a dense phase section at the bottom of the second reaction zone 11b at 0.7-3.5m / s, and the preferred operating range of the superficial gas velocity is 0.9-2.5m / s; correspondingly, the ratio of the inner diameter of the second reaction zone 11b to the first reaction zone 11a in the present invention is larger. Preferably, the ratio of the inner diameter of the second reaction zone 11b to the first reaction zone 11a is 2-5:1, and more preferably 1.7-3.5:1.

[0047] In the present invention, when the catalytic cracking device is in use, the multi-stage reaction unit 1 and the cracking reaction unit 2 are usually arranged vertically, the length direction of the multi-variable riser 11 is the vertical direction, the first reaction zone 11a, the second reaction zone 11b and the third reaction zone 11c are connected in sequence from bottom to top, the length direction of the cracking settler 23 is also the vertical direction, the cracking stripping section 23a, the turbulent reaction section 23b and the cracking sedimentation section 23c are connected in sequence from bottom to top; the multi-stage reaction settler 12 and the multi-variable riser 11 can be coaxially arranged or arranged in parallel.

[0048] In the present invention, the multi-stage reaction settler 12 generally includes a multi-stage reaction stripping section 12a and a multi-stage reaction settling section 12b arranged from bottom to top, and the multi-stage reaction settling section 12b is provided with a single-stage or multi-stage reaction cyclone separator 12c, so that the material of the multi-variable diameter riser 11 can enter the multi-stage reaction settling section 12b and be separated by the multi-stage reaction cyclone separator 12c, so that the separated catalyst to be regenerated enters the multi-stage reaction stripping section 12a and is stripped by the multi-stage reaction stripping steam F and then discharged, and can enter the catalyst regenerator for air charring regeneration treatment and then return to the multi-stage reaction unit 1 for recycling.

[0049] The basic implementation of the catalytic cracking device provided above, when applied to catalytic cracking, comprises the following steps:

[0050] The heavy raw material is atomized by steam and mixed with a multi-stage reaction catalyst at the bottom of the first reaction zone 11a to form a multi-stage reaction mixture. The multi-stage reaction mixture is input from the inlet of the first reaction zone 11a, and enters the first reaction zone 11a and the second reaction zone 11b in sequence. The expansion of the second reaction zone 11b can prolong the residence time of the multi-stage reaction mixture and fully mix and contact, fully complete the secondary reaction of the heavy oil and its intermediate fraction, and then enter the third reaction zone 11c from the inner delivery pipe 13 to perform a multi-stage catalytic reaction to obtain a multi-stage reactant. Since the inner delivery pipe 13 and the lifting delivery pipe of the third reaction zone 11c are reduced in diameter to increase the flow rate of the mixture, the mixture quickly enters the multi-stage reaction settler 12 for multi-stage reaction separation to obtain a multi-stage reaction oil and gas product and a multi-stage reaction catalyst to be produced. The multi-stage reaction catalyst to be produced with carbon after the reaction is discharged with or without steam stripping;

[0051] The cracking mixture formed by mixing the light raw material and the cracking catalyst is input from the inlet of the cracking riser 21, and undergoes a cracking catalytic reaction through the cracking riser 21 to obtain a cracking reactant. The cracking reactant enters the turbulent reaction section 23b for a turbulent reaction, and then undergoes cracking separation through the cracking settling section 23c, and undergoes cracking stripping through the cracking stripping section 23a to obtain a cracking oil and gas product and a cracking catalyst to be produced.

[0052] The catalyst to be produced by cracking is introduced into the second reaction zone 11b from the cracking catalyst outlet 25 and mixed with the multi-stage reaction mixture to increase the activity and density of the multi-stage reaction catalyst in the second reaction zone 11b.

[0053] In the present invention, the heavy raw material is petroleum hydrocarbon and / or other mineral oil, the petroleum hydrocarbon is selected from at least one of vacuum gas oil (VGO), atmospheric gas oil (AGO), coker gas oil (CGO), deasphalted oil (DAO), vacuum residue oil (VR), atmospheric residue oil (AR) and hydrogenated heavy oil; other mineral oils are selected from at least one of coal liquefaction oil, oil sand oil and shale oil. Preferably, the heavy raw material is selected from at least one of vacuum gas oil, atmospheric gas oil, coker gas oil, deasphalted oil, vacuum residue oil, atmospheric residue oil and hydrogenated heavy oil; wherein VGO, AGO, CGO, DAO, VR, AR are unhydrogenated whole fractions or partial fractions, or are hydrogenated whole fractions or partial fractions.

[0054] In the present invention, the light raw material is selected from at least one of olefin-rich gasoline, diesel, and light hydrocarbons with carbon atoms of 4-8 that are not rich in olefins / rich in olefins. The olefin-rich gasoline can be gasoline obtained by catalytic cracking using the device provided by the present invention, conventional catalytic cracking gasoline, other catalytic cracking gasoline, coking gasoline, thermal cracking gasoline, thermal cracking gasoline, or a mixture of more than one of them; the light hydrocarbons not rich in olefins can be selected from straight-run naphtha, straight-run gasoline, hydrogenated naphtha, alkanes with carbon atoms of 4-8, and raffinate oil, or a mixture of more than one of them.

[0055] In the present invention, the multi-stage reaction catalyst and the cracking catalyst in the method can be all types of catalytic cracking or catalytic cracking catalysts, and the active components thereof are selected from one or more catalysts selected from Y or HY type zeolites containing or not containing rare earth, ultrastable Y type zeolites containing or not containing rare earth, ZSM-5 series zeolites or high silicon zeolites with a five-membered ring structure prepared by other methods, and amorphous silicon-aluminum catalysts. The multi-stage reaction catalyst and the cracking catalyst can be the same catalyst or different catalysts.

[0056] During the use of the above device, in order to control the reaction temperature of the multi-stage reaction unit 1, a quenching agent can be injected at any position of the upper part of the first reaction zone 11a and the middle part of the second reaction zone 11b of the multi-stage reaction unit 1. Preferably, a quenching oil and gas unit 9 is provided from the top of the first reaction zone 11a to the bottom of the second reaction zone 11b. The quenching agent can be selected from at least one of water, recycled oil, gasoline, diesel and waste oil, and the injection amount is 1-10wt% of the amount of catalytic raw material (heavy raw material), and the temperature of the quenching agent is 10-200°C, preferably 10-30°C.

[0057] In the present invention, most of the catalyst in the cracking reaction unit 2 falls into the turbulent reaction section 23b, so that the catalyst density of the turbulent reaction section 23b and the cracking stripping section 23a is relatively large. By controlling the catalyst to be transported out from the bottom of the cracking settler 23, the catalyst in the middle and top of the cracking settler 23 gradually falls into the cracking stripping section 23a at the bottom. The catalyst that falls into the cracking stripping section 23a can be output from the cracking catalyst outlet 25 after or without steam stripping. The cracking catalyst outlet 25 is connected to any position from the end of the first reaction zone 11a to the middle of the second reaction zone 11b through a pipeline to input the cracking catalyst to be generated into the second reaction zone 11b of the multi-variable riser 11. In addition, a pipeline can be added to connect the cracking catalyst outlet 25 to the catalyst regenerator for recovery. Preferably, the cracking catalyst outlet 25 is located at the bottom of the cracking stripping section 23a and is connected to the bottom of the second reaction zone 11b (one end close to the first reaction zone 11a) through a pipeline. A sliding valve can be provided on the pipeline to adjust the amount of cracking catalyst to be input into the second reaction zone 11b by controlling the opening of the sliding valve, and the catalyst stock in the cracking settler 23 can also be adjusted.

[0058] Since the cracking catalyst has a low coke content and a high temperature after the reaction with light hydrocarbons, it still has a high catalytic activity. When it is input into the second reaction zone 11b, the flow rate of the catalyst and its catalytic activity are increased, which is beneficial to strengthening the catalytic reaction in the multi-variable riser 11; the oil and gas after the reaction of the light hydrocarbons separated by the cracking settler 23 do not enter the various reaction zones of the multi-variable riser 11 for the heavy oil reaction, and do not affect the oil and gas flow rate and flow velocity of the second reaction zone 11b, and thus do not affect the gas-solid fluidization of the second reaction zone 11b, and at the same time shorten the residence time of the light hydrocarbons in the high-temperature reaction zone in the cracking reaction unit 2, thereby reducing the degree of thermal cracking reaction.

[0059] In the present invention, the inner diameter of the inner delivery pipe 13 is smaller than that of the second reaction zone 11b. Preferably, the ratio of the inner diameters of the inner delivery pipe 13 to the third reaction zone 11c is 0.9-1.2:1, and more preferably, the ratio of the inner diameters of the inner delivery pipe 13 to the third reaction zone 11c is 0.95-1.05:1, so that the inner diameters of the two are equivalent, so as to further widen the adjustment range of the apparent linear velocity of the gas in the second reaction zone 11b, so that the reaction oil and gas flow rate (representing the processing capacity of the device) that the multi-stage reaction unit 1 can withstand can be adjusted or fluctuated within a larger range.

[0060] In the present invention, the length of the inner delivery pipe 13 is less than the length of the second reaction zone 11b. Preferably, the ratio of the length of the inner delivery pipe 13 to the second reaction zone 11b is 0.15-0.8:1, more preferably 0.2-0.6:1, which can better make the gas-solid fluidization state and turbulence effect in the second reaction zone 11b better. It should be noted that the second reaction zone 11b can be cylindrical, or a truncated cone with a gradually expanding diameter from bottom to top, or a cylindrical shape with two or three stages of expansion; the height of the second reaction zone 11b refers to the sum of the heights of its own region, the transition section between it and the first reaction zone 11a, and the transition section between it and the third reaction zone 11c.

[0061] In the present invention, as a preferred embodiment of the inner transport pipe 13, the distance between the bottom port of the inner transport pipe 13 and the bottom of the second reaction zone 11b (i.e., the outlet of the first reaction zone 11a) is 2-8m, preferably 3-6m; the length of the inner transport pipe 13 is 2-7m, preferably 3-5m; at this time, the height of the turbulent bed in the second reaction zone 11b can be better controlled.

[0062] The inventors of the present invention have found through research on the catalyst particles in the variable diameter riser, especially the expanded diameter section, that from the perspective of axial distribution, the axial density of the particles in the expanded diameter section is "S-shaped" with a thin top and a dense bottom distribution. Although the height of the dense phase section is affected by the gas velocity and the particle delivery amount, it is concentrated in the bottom section below 60% of the height of the expanded diameter section. From the perspective of radial distribution of catalyst particles, at any cross section of the reactor, the maximum velocity of the catalyst particles is at the center of the riser, and the particle velocity maintains a relatively large and relatively constant value in the central area. The degree of decline from the center to the tube wall is relatively slow. After r / R (r represents the distance from the central axis, and R is the pipe radius) reaches a certain value, the particle velocity suddenly decreases and is almost zero near the side wall. The side wall effect exists in the entire variable diameter riser. In the lower pneumatic conveying riser, the gas velocity is above 10m / s, and the axial velocity of the catalyst particles in the region of r / R<0.8 is relatively high. However, in the expansion section, due to the gas superficial velocity of 1.5-3m / s, the side wall effect is more obvious; in the lower part of the expansion section, the catalyst particle velocity is relatively high in the region of r / R<0.7, but the axial velocity of the catalyst particles close to the side wall is zero or even negative; in the upper part of the expansion section, the catalyst particle velocity is relatively high in the region of r / R<0.6, but the catalyst particle velocity close to the side wall is maintained at around 0, that is, a large part of the catalyst is suspended in this section, and this part of the catalyst may stay in the expansion section for too long, affecting the best process effect. Based on this, in a preferred case, at least one inner delivery hole 13a is provided on the side wall of the inner delivery pipe 13, and the distance between the inner delivery hole 13a and the entrance of the third reaction zone 11c is 0.5-2m. The setting of the inner delivery hole 13a enables the gas in the upper part of the second reaction zone 11b of the expanded diameter section and the coaxial part of the inner delivery pipe 13 to be in a flowing state, so as to prevent the appearance of a dead zone without gas flow in the upper part of the second reaction zone 11b, so as to further improve the turbulence effect and catalytic reaction efficiency in the second reaction zone 11b.

[0063] In the present invention, it is preferred that a plurality of inner delivery holes 13a are provided, and they can be evenly distributed circumferentially on the inner delivery tube 13. Further preferably, the ratio of the total area of ​​at least one inner delivery hole 13a to the cross-sectional area of ​​the inner delivery tube 13 is 0.05-0.3:1. The cross-sectional area of ​​the inner delivery tube 13 refers to the area of ​​the cross section perpendicular to the length direction of the inner delivery tube 13.

[0064] In the present invention, the transition section between the first reaction zone 11a and the second reaction zone 11b, and the transition section between the second reaction zone 11b and the third reaction zone 11c are dome-shaped or truncated cone-shaped, and are coaxially arranged with the entire multi-stage reaction unit 1. Preferably, the first reaction zone 11a, the second reaction zone 11b, the third reaction zone 11c and the inner transport pipe 13 are coaxially arranged.

[0065] As a preferred embodiment, the ratio of the inner diameters of the first reaction zone 11a, the second reaction zone 11b and the third reaction zone 11c is 1:2-5:0.7-1.5, and the ratio of the lengths is 1:0.3-2:0.5-2. In this case, it is more conducive to prolonging the residence time of the oil agent in the second reaction zone 11b and fully mixing and contacting, so as to fully complete the secondary reaction of the heavy oil and its intermediate fractions.

[0066] In the present invention, the cracking settler 23 is a two-stage expansion structure, the outer diameters of the cylinders of the cracking stripping section 23a, the turbulent reaction section 23b and the cracking settling section 23c are increased successively, and the cracking riser 21 is located in the turbulent reaction section 23b or in the transition section between the turbulent reaction section 23b and the cracking settling section 23c. As a preferred embodiment of the cracking separator 23, the ratio of the inner diameters of the turbulent reaction section 23b, the cracking stripping section 23a and the cracking settling section 23c is 1:0.4-0.8:2.5-5, and the ratio of the lengths is 1:1.5-3:1.5-4. At this time, it is more conducive to the efficient and sufficient reaction of light hydrocarbons and catalysts in the turbulent reaction section 23b, and the efficient contact reaction of light hydrocarbons and catalysts at a lower temperature and low space velocity is achieved.

[0067] In the present invention, the cracking riser 21 and the cracking settler 23 of the cracking reaction unit 2 are preferably coaxially arranged.

[0068] As a preferred embodiment of the present invention, the ratio of the length of the multi-diameter riser 11 to the cracking riser 21 is 1:0.5-1.2, more preferably 1:0.6-1. The ratio of the inner diameter of the first reaction zone 11a in the multi-diameter riser 11 to the inner diameter of the cracking riser 21 is 1:0.2-1. At this time, the coupling effect between the multi-stage reaction unit 1 and the cracking reaction unit 2 can be better achieved. Generally, the height of the multi-diameter riser 11 in a medium-sized device in a laboratory is about 20 meters; the height of the variable diameter riser 11 in industrial production is about 40 meters.

[0069] As another preferred embodiment of the present invention, see Figure 2 The second reaction zone 11b is provided with a distribution internal member 14 connected to the first reaction zone 11a, and a plurality of distribution holes 14a are provided on the distribution internal member 14, that is, the distribution internal member 14 is an open-hole distribution member. The main body of the distribution internal member 14 is located in the transition section between the first reaction zone 11a and the second reaction zone 11b, and its function is to quickly reduce the high-speed gas-solid particles in the first reaction zone 11a to the gas-solid fluidized state required by the second reaction zone 11b.

[0070] In the present invention, the distribution internal component 14 can be an open distribution plate with an opening rate of 8-35%; or a cap-type distributor with a mushroom head, a cone or an umbrella-shaped top and outputting oil and gas from a side channel can be used. The cap-type distributor can be a conventional umbrella-shaped distributor, a mushroom head distributor or a conical cap-shaped distributor. Specifically, the distribution internal component 14 includes a distribution tube 14b connected to the first reaction zone 11a and an end distribution plate 14c connected to the distribution tube 14b. The distribution tube 14b and the end distribution plate 14c are both provided with distribution holes 14a. The end distribution plate 14c is located at one end of the distribution tube 14b away from the first reaction zone 11a. Among them, the end distribution plate 14c can be an umbrella-shaped or dome-shaped, for example, an arched (convex) distribution plate, a special-shaped (basin-shaped) distribution plate, or a concave distribution plate.

[0071] As a preferred embodiment of the end distribution plate 14c, the ratio of the sum of the areas of the multiple distribution holes 14a opened on the end distribution plate 14c (i.e., the total hole area) to the vertical projection area of ​​the end distribution plate 14c is 0.1-0.3:1, which can make the gas above the end distribution plate 14c flow smoothly and prevent the accumulation of catalyst on the end distribution plate 14c. The vertical projection area of ​​the end distribution plate 14c refers to the area occupied by the shadow of the outer contour of the end distribution plate 14c on the vertical plane after the horizontal parallel light irradiates the end distribution plate 14c.

[0072] In the present invention, the distribution holes 14a on the distribution cylinder 14b may be rectangular or elliptical. Preferably, the ratio of the sum of the areas of the distribution holes 14a on the distribution cylinder 14b to the cross-sectional area of ​​the first reaction zone 11a is 0.6-4:1, which can better improve the deceleration and distribution effect of the high-speed gas-solid particles in the first reaction zone 11a. The cross-sectional area of ​​the first reaction zone 11a refers to the area of ​​the cross section perpendicular to the length direction of the first reaction zone 11a.

[0073] As a preferred embodiment of the distribution tube 14b, a side channel 14d extending to the outside of the distribution tube 14b is provided at the distribution hole 14a on the distribution tube 14b, and the opening section of the side channel 14d away from the distribution tube 14b is an inclined surface facing the first reaction zone 11a. The cross section of the side channel 14d (the cross section perpendicular to the length direction of the side channel 14d) corresponds to the distribution hole 14a on the distribution tube 14b, and can be rectangular or elliptical. The opening section of the side channel 14d away from the distribution tube 14b is generally not perpendicular to the axis of the side channel 14d, and the opening section is an inclined surface facing the first reaction zone 11a, that is, the extension line of the section is at a certain oblique upward angle with the axis of the multi-stage reaction unit 1; the upper part of the opening section is a part of the side channel 14d, so as to avoid the outlet of the side channel 14d from being blocked by the catalyst as much as possible, and ensure the patency of the outlet of the side channel 14d.

[0074] As another preferred embodiment of the distribution tube 14b, the ratio of the area of ​​the end distribution plate 14c to the cross-sectional area of ​​the second reaction zone 11b is 0.7-0.85:1, so that the gas velocity at the edge of the end distribution plate 14c is above 2.5m / s, preferably above 3.5m / s, to ensure that no catalyst accumulation occurs at the bottom of the second reaction zone 11b or even in the transition section to cause an operation accident of the device. The area of ​​the end distribution plate 14c is the projected area of ​​the outer contour of the end distribution plate 14c, and the cross-sectional area of ​​the second reaction zone 11b is the area of ​​the cross section perpendicular to the length direction of the second reaction zone 11b.

[0075] In the present invention, a wear-resistant lining, such as a ceramic wear-resistant lining, is installed or coated in the inner conveying hole 13a and / or the distribution hole 14a.

[0076] In the present invention, in order to fully mix the raw materials and the catalyst, preferably, the multi-variable riser 11 also includes a multi-stage reaction pre-lifting section 11d connected to the inlet of the first reaction zone 11a, and the cracking riser 21 includes a cracking pre-lifting section 21b and a cracking reaction section 21a connected in series along its length direction, and the outlet of the cracking reaction section 21a is located at one end of the turbulent reaction section 23b close to the cracking stripping section 23a, the transition section between the multi-stage reaction pre-lifting section 11d and the first reaction zone 11a is connected to the multi-stage reaction feed unit 7, and the transition section between the cracking pre-lifting section 21b and the cracking reaction section 21a is connected to the cracking feed unit 8. Multistage reaction pre-lifting gas A is injected through the multistage reaction pre-lifting section 11d, mixed with the multistage reaction catalyst and then ascended, and the heavy raw material atomized by water vapor enters the multi-variable diameter riser 11 from the multistage reaction feeding unit 7, so that the heavy raw material and the multistage reaction catalyst contact and react in the first reaction zone 11a; cracking pre-lifting gas B is injected through the cracking pre-lifting section 21b, mixed with the cracking catalyst and then ascended, and the light raw material atomized by water vapor enters the cracking riser 21 from the cracking feeding unit 8, so that the light raw material and the cracking catalyst contact and react in the cracking reaction section 21a.

[0077] In the present invention, in order to improve the contact effect between the catalyst and the light hydrocarbons after the light hydrocarbon reaction mixture enters the turbulent reaction section 23b and improve the catalytic reaction efficiency, preferably, a cracking distributor 22 is provided at the outlet of the cracking reaction section 21a.

[0078] In the present invention, the gas phase outlet of the cracking and settling section 23c can be merged into the main oil and gas pipeline, or can be communicated with the multi-stage reaction settler 12. For example, a gas collecting chamber is provided at the top of the multi-stage reaction settler 12, and the gas phase outlet of the cracking and settling section 23c is communicated with the gas collecting chamber through the cracking gas phase delivery pipe 24, so that the reacted oil and gas E (including the reacted oil and gas of the heavy raw material and the reacted oil and gas of the light raw material) are discharged from the gas collecting chamber. The bottom of the cracking and stripping section 23a can be provided with a stripping steam unit 10 to pass steam to strip the catalyst in the cracking and stripping section 23a.

[0079] When the catalytic cracking device provided by the present invention is used, the multi-stage reaction unit 1 and the cracking reaction unit can be respectively equipped with corresponding catalyst regenerators. When the multi-stage reaction catalyst and the cracking catalyst are the same, the two can also share a catalyst regenerator. As a preferred embodiment of the present invention, the device also includes a regeneration unit 3, and the multi-stage reaction settler 12 is provided with a multi-stage reaction catalyst outlet 15 connected to the feed inlet of the regeneration unit 3, and the regeneration catalyst outlet 31 of the regeneration unit 3 is connected to the multi-variable riser 11 and / or the cracking riser 21. Among them, the cracking catalyst outlet 25 is not only connected to the second reaction zone 11b, but also connected to the feed inlet of the regeneration unit 3, so that part of the catalyst to be regenerated of the cracking reaction unit 2 is directly input into the regeneration unit 3.

[0080] In the present invention, a regeneration cyclone separator 32 is arranged in the regeneration unit 3, and a regeneration air inlet 33 is arranged at the bottom and a regeneration flue gas outlet 34 is arranged at the top. The catalyst to be regenerated enters the regeneration unit 3 through the regeneration pipeline 5, and contacts with the regeneration air C entering through the regeneration air inlet 33 to undergo an oxidation reaction. The regeneration flue gas D is output from the regeneration flue gas outlet 34 and enters the flue gas turbine for further energy recovery and treatment. The high-temperature regenerated catalyst generated by burning the coke enters the catalyst heat exchanger 4 through the regeneration pipeline 6, and the low-temperature water vapor G enters the catalyst heat exchanger 4 from the heat extraction steam inlet to extract heat from the regenerated catalyst to become high-temperature water vapor H, which is output from the heat extraction steam outlet. The cooled regenerated catalyst flows back to the bottom of the first reaction zone 11a and the bottom of the cracking riser 21 through the regeneration pipeline 6 for recycling.

[0081] In the present invention, part or all of the multi-stage reaction catalyst and part or all of the cracking catalyst adopt the regenerated catalyst outputted from the regenerated catalyst outlet 31 .

[0082] Based on the catalytic cracking device provided above, the second aspect of the present invention provides a method for applying the device to catalytic cracking, the method comprising the following steps:

[0083] The multi-stage reaction mixture formed by mixing the heavy raw material and the multi-stage reaction catalyst is input from the inlet of the first reaction zone 11a, enters the first reaction zone 11a and the second reaction zone 11b in sequence, and then enters the third reaction zone 11c from the inner delivery pipe 13 to perform a multi-stage catalytic reaction to obtain a multi-stage reactant. The multi-stage reactant is separated by a multi-stage reaction in the multi-stage reaction settler 12 to obtain a multi-stage reaction oil and gas product and a multi-stage reaction catalyst to be produced;

[0084] The cracking mixture formed by mixing the light raw material and the cracking catalyst is input from the inlet of the cracking riser 21, and undergoes a cracking catalytic reaction through the cracking riser 21 to obtain a cracking reactant. The cracking reactant enters the turbulent reaction section 23b for a turbulent reaction, and then undergoes cracking separation through the cracking settling section 23c, and undergoes cracking stripping through the cracking stripping section 23a to obtain a cracking oil and gas product and a cracking catalyst to be produced.

[0085] The catalyst to be produced by cracking is introduced into the second reaction zone 11b from the cracking catalyst outlet 25 and mixed with the multi-stage reaction mixture.

[0086] The device and method provided by the present invention have multiple operation modes. For example, in the ultra-low olefin gasoline operation mode, the multi-stage reaction unit 1 adopts a catalyst with high gasoline production and olefin reduction function, controls the catalyst circulation amount, the quenching agent injection amount of the quenching oil and gas unit 9, does not supplement or supplements an appropriate amount of regeneration agent or a cooled regeneration agent (the temperature is generally 560-660° C.) or a carbon-containing catalyst to be regenerated with a carbon content of <0.5% at the bottom or middle of the second reaction zone 11b, and controls the temperature in the second reaction zone 11b to be 510-540° C., with an optimization range of 515-530° C., and controls the inlet temperature of the inner delivery pipe 13 to be 510-540° C., with an optimization range of 515-530° C., so as to realize the production mode of ultra-low olefin gasoline;

[0087] At the same time, the cracking reaction unit 2 cracks various olefin-rich catalytic light gasoline, coker gasoline, etc., which can further reduce the amount of high-olefin gasoline throughout the plant and reduce the olefin content in the gasoline pool of the whole plant. The outlet temperature of the cracking riser 21 is controlled at 540-620°C, preferably 560-600°C.

[0088] For another example, in the high-yield cracking gas mode, the multi-stage reaction unit 1 uses a catalytic cracking catalyst that produces high-yield cracking gas, and the bottom or middle of the second reaction zone 11b is not supplemented or supplemented with an appropriate amount of regeneration agent or a cooled regeneration agent (temperature is generally 580-680°C) or a carbon-containing catalyst to be regenerated with a carbon content of <0.5% (temperature is generally 580-680°C), and the temperature in the second reaction zone 11b is controlled at 560-660°C, with an optimization range of 560-600°C, and the inlet temperature of the inner delivery pipe 13 is controlled at 550-640°C, with an optimization range of 560-600°C, so that the high-yield cracking gas operation mode can be achieved;

[0089] At the same time, the cracking reaction unit 2 recycles light hydrocarbons rich in C4-C8 olefins, or gasoline or diesel, and the outlet temperature of the cracking riser 21 is controlled at 560-660°C, preferably 580-640°C; in this way, the cracking gas output of the whole plant can be further increased, that is, the output of raw materials required for light hydrocarbon processing units such as MTBE, light gasoline etherification, and polypropylene can be increased, and the refining product structure of the whole plant can be adjusted.

[0090] In the present invention, the temperature of the regenerated catalyst before the heavy feedstock or light feedstock contacts the catalyst (ie, the oil agent) is 660-760°C.

[0091] Based on the device and method provided by the present invention, the apparent residence time of oil and gas in the multi-stage reaction mixture in the first reaction zone 11a is 0.8-2s, the apparent residence time of oil and gas in the second reaction zone 11b is 5-15s, and the apparent residence time of oil and gas in the third reaction zone 11c is 0.5-1.5s; the residence time of the cracking mixture in the cracking riser 21 is 0.8-3.5s, more preferably 1-2.5s; the residence time in the turbulent reaction section 23b is 3-13s.

[0092] As a relatively preferred specific embodiment of the catalytic cracking device in the present invention, the catalytic cracking device includes a multi-stage reaction unit 1, a cracking reaction unit 2 and a regeneration unit 3, the multi-stage reaction unit 1 includes a multi-variable diameter riser 11 and a multi-stage reaction settler 12; the multi-variable diameter riser 11 includes a multi-stage reaction pre-lifting section 11d, a first reaction zone 11a, a second reaction zone 11b and a third reaction zone 11c which are connected in series and coaxially along its length direction, the outlet of the third reaction zone 11c is connected to the multi-stage reaction settler 12, a quenching oil and gas unit 9 is arranged from the top of the first reaction zone 11a to the bottom of the second reaction zone 11b, and the ratio of the inner diameters of the first reaction zone 11a, the second reaction zone 11b and the third reaction zone 11c is The ratio of the diameter of the inner tube 13 to the diameter of the third reaction zone 11c is 1:2-5:0.7-1.5, the ratio of the length is 1:0.3-2:0.5-2, an inner delivery pipe 13 extending into the second reaction zone 11b is provided at the connection between the third reaction zone 11c and the second reaction zone 11b, the ratio of the inner diameter of the inner delivery pipe 13 to the inner diameter of the third reaction zone 11c is 0.9-1.2:1, the ratio of the length of the inner delivery pipe 13 to the second reaction zone 11b is 0.15-0.8:1, a plurality of inner delivery holes 13a are provided on the side wall of the inner delivery pipe 13, the distance between the inner delivery hole 13a and the entrance of the third reaction zone 11c is 0.5-2m, the ratio of the total area of ​​the plurality of inner delivery holes 13a to the cross-sectional area of ​​the inner delivery pipe 13 is 0.05-0.3:1, and the second reaction zone 11c is 1:2-5:0.7-1.5, the ratio of the length of the inner delivery pipe 13 to the second reaction zone 11b is 1:0.3-2:0.5-2, an inner delivery pipe 13 extending into the second reaction zone 11b is provided at the connection between the third reaction zone 11c and the second reaction zone 11b, the ratio of the inner diameter of the inner delivery pipe 13 to the inner diameter of the third reaction zone 11c is 0.9-1.2:1, the ratio of the length of the inner delivery pipe 13 to the second reaction zone 11b is 0.15-0.8:1, a plurality of inner delivery holes 13a are provided on the side wall of the inner delivery pipe 13, the distance between the inner delivery hole 13a and the entrance of the third reaction zone 11c is 0.5-2m The zone 11b is provided with a distribution internal component 14 connected to the first reaction zone 11a, and the distribution internal component 14 includes a distribution cylinder 14b connected to the first reaction zone 11a and an end distribution plate 14c connected to the distribution cylinder 14b, and a plurality of distribution holes 14a are provided on the distribution cylinder 14b and the end distribution plate 14c, and the end distribution plate 14c is located at one end of the distribution cylinder 14b away from the first reaction zone 11a, and the ratio of the area of ​​the end distribution plate 14c to the cross-sectional area of ​​the second reaction zone 11b is 0.7-0.85:1, and the ratio of the sum of the areas of the plurality of distribution holes 14a provided on the end distribution plate 14c to the vertical projection area of ​​the end distribution plate 14c is 0.1-0.3:1, and the distribution holes 14a on the distribution cylinder 14b are 0.7-0.85:1. The ratio of the sum of the areas of a and the cross-sectional area of ​​the first reaction zone 11a is 0.6-4:1, a side channel 14d extending to the outside of the distribution tube 14b is provided at the distribution hole 14a on the distribution tube 14b, and the opening section of the side channel 14d away from the distribution tube 14b is an inclined surface facing the first reaction zone 11a, and the transition section between the multi-stage reaction pre-lifting section 11d and the first reaction zone 11a is connected to the multi-stage reaction feeding unit 7, and the multi-stage reaction settler 12 includes a multi-stage reaction stripping section 12a and a multi-stage reaction settling section 12b arranged from bottom to top, and a primary or multi-stage reaction cyclone separator 12c is arranged in the multi-stage reaction settling section 12b, and a multi-stage reaction catalyst outlet 15 is arranged at the bottom of the multi-stage reaction stripping section 12a;

[0093] The cracking reaction unit 2 includes a cracking riser 21 and a cracking settler 23 which are coaxially arranged. The cracking riser 21 includes a cracking pre-lifting section 21b and a cracking reaction section 21a which are sequentially connected in series along its length direction. The transition section between the cracking pre-lifting section 21b and the cracking reaction section 21a is connected to the cracking feeding unit 8. The cracking settler 23 includes a cracking stripping section 23a, a turbulent reaction section 23b and a cracking settling section 23c which are sequentially arranged along its length direction. The outlet of the cracking reaction section 21a is located at one end of the turbulent reaction section 23b close to the cracking stripping section 23a. A cracking settling section 23c is provided at the outlet of the cracking reaction section 21a. The distributor 22, the bottom of the cracking stripping section 23a is provided with a cracking catalyst outlet 25 connected to the bottom of the second reaction zone 11b, the inner diameter ratio of the turbulent reaction section 23b, the cracking stripping section 23a and the cracking settling section 23c is 1:0.4-0.8:2.5-5, and the length ratio is 1:1.5-3:1.5-4, a single-stage or two-stage cracking cyclone separator 23d is arranged in the cracking settling section 23c, the gas phase outlet of the cracking settling section 23c is connected to the gas collecting chamber at the top of the multi-stage reaction settler 12 through the cracking gas phase conveying pipe 24, and the bottom of the cracking stripping section 23a is provided with a stripping steam unit 10;

[0094] A regeneration cyclone separator 32 is provided in the regeneration unit 3, and a regeneration catalyst outlet 31 is provided on the side wall, a regeneration air inlet 33 is provided at the bottom, and a regeneration flue gas outlet 34 is provided at the top. The multi-stage reaction catalyst outlet 15 and the cracking catalyst outlet 25 are both connected to the feed port of the regeneration unit 3 through the waiting pipeline 5. The regeneration catalyst outlet 31 is connected to the multi-stage reaction pre-lift section 11d and the cracking pre-lift section 21b through the regeneration pipeline 6, and a catalyst heat collector 4 is provided on the regeneration pipeline 6;

[0095] The length ratio of the multi-variable riser 11 to the cracking riser 21 is 1:0.5-1.2, and wear-resistant linings are installed or coated in the inner conveying holes 13a and the distribution holes 14a.

[0096] The present invention will be described in detail below through examples.

[0097] In the following examples, heavy raw materials (heavy oil), light hydrocarbons I, and light hydrocarbons II were all provided by a refinery of China Petrochemical Corporation, catalysts I and II were all provided by China Petrochemical Catalyst Co., Ltd., and product distribution and gasoline composition were detected by chromatography; unless otherwise specified, the remaining raw materials were conventional commercial products, and the parameters involved were all based on existing corresponding methods.

[0098] Example 1

[0099] A relatively preferred specific embodiment of the catalytic cracking device provided above is used to process the heavy feedstock oil in Table 1 using the catalyst I in Table 2 to produce ultra-low olefin gasoline. The properties of the feedstock in Example 1 are shown in Table 1. The recycled light gasoline uses light hydrocarbon A as the light hydrocarbon feedstock, and the recycled light gasoline accounts for 30% of the heavy feedstock, half of which is the light gasoline produced by the device itself, and the other half comes from other devices outside the device.

[0100] In the device provided in Example 1, the total length of the multi-variable riser 11 is about 18 meters, the diameter of the multi-stage reaction pre-lifting section 11d is 0.25 meters, and the height is 1.5 meters. The diameter of the first reaction zone 11a is 0.30 meters, and the height is 4 meters; the diameter of the second reaction zone 11b is 1.2 meters, and the height is 7.6 meters. The diameter of the inner delivery pipe 13 is 0.30 meters, and the height is 2.5 meters; the diameter of the third reaction zone 11c is 0.30 meters, and the height is 4 meters. The longitudinal section of the junction of the first reaction zone 11a and the second reaction zone 11b is an isosceles trapezoid, and the angle between the side line of the isosceles trapezoid and the axis is 45°, and the height of the isosceles trapezoid is 0.45 meters; the longitudinal section of the junction of the second reaction zone 11b and the third reaction zone 11c is 0.30 meters, and the height of the isosceles trapezoid is 0.45 meters. The surface is an isosceles trapezoid, the angle between the side line of the isosceles trapezoid and the axis is 45°, and the height of the isosceles trapezoid is 0.45 meters; the distance between the inner delivery hole 13a and the entrance of the third reaction zone 11c is 1 meter, the ratio of the total area of ​​the multiple inner delivery holes 13a to the cross-sectional area of ​​the inner delivery pipe 13 is 0.2:1, the distribution internal component 14 forms a cap-shaped distribution internal component, the ratio of the area of ​​the end distribution plate 14c to the cross-sectional area of ​​the second reaction zone 11b is 0.8:1, the ratio of the sum of the areas of the multiple distribution holes 14a opened on the end distribution plate 14c to the vertical projection area of ​​the end distribution plate 14c is 0.2:1, and the ratio of the sum of the areas of the distribution holes 14a on the distribution tube 14b to the cross-sectional area of ​​the first reaction zone 11a is 2:1;

[0101] The total height of the cracking riser 21 is 13 meters, of which the height of the cracking pre-lifting section 21b is 2 meters and the diameter is 0.12 meters, the height of the cracking reaction section 21a is 11 meters and the diameter is 0.15 meters, the height of the cracking stripping section 23a is 3 meters and the diameter is 0.35 meters, the height of the turbulent reaction section 23b is 1.5 meters and the diameter is 0.5 meters, the height of the cracking sedimentation section 23c is 2.5 meters and the diameter is 1.3 meters, and the diameter of the cracking gas phase conveying pipe 24 is 0.2 meters.

[0102] The multi-stage reaction pre-lift gas A entering from the bottom of the multi-stage reaction pre-lift section 11d is mixed with the regenerated catalyst (catalyst I) directly transported from the catalyst heat collector 4 or the regeneration unit 3 through the regeneration pipeline 6 and moves upward. At the connection between the top of the multi-stage reaction pre-lift section 11d and the main body of the first reaction zone 11a, the heavy raw material atomized by water vapor enters the multi-diameter riser 11 through the heavy oil feeding system 7, and the oil agent contacts and reacts in the first reaction zone 11a, and moves upward along the multi-diameter riser 11 through the distribution internal component 14 to enter the second reaction zone 11b; due to the decrease in the apparent velocity of oil and gas and the diversion of oil and gas, the catalyst in the second reaction zone 11b is in a turbulent bed or dense phase transport bed state, which strengthens the contact of the oil agent; in the transition section between the second reaction zone 11b and the first reaction zone 11a, a quenching agent can be injected from the quenching oil and gas unit 9, and the catalyst to be regenerated output from the cracking catalyst outlet 25 can be injected from the bottom of the second reaction zone 11b to supplement the catalyst activity in the second reaction zone 11b;

[0103] The cracking pre-lift gas B is injected from the bottom of the cracking pre-lift section 21b and mixed with the regenerated catalyst (catalyst I) directly from the catalyst heat collector 4 or the regeneration unit 3 to move upward. At the connection between the top of the cracking pre-lift section 21b and the cracking reaction section 21a, the light raw material (light hydrocarbon I) atomized by water vapor or directly mechanically atomized enters the cracking riser 21 through the cracking feed unit 8. The light raw material and the catalyst contact and react in the cracking reaction section 21a and move upward, and enter the bottom of the turbulent reaction section 23b through the cracking distributor 22 at the top end of the cracking reaction section 21a, and the oil after the reaction is The gas and the catalyst are separated; the catalyst is stripped at the bottom of the cracking stripping section 23a with or without the steam introduced by the stripping steam unit 10, and then sent to the second reaction zone 11b through the cracking catalyst outlet 25, and the separated light hydrocarbon reaction oil and gas enter the gas collecting chamber at the top of the multi-stage reaction settler 12 through the light hydrocarbon delivery pipe on the cracking settling section 23c or directly enter the multi-stage reaction settler 12; the multi-stage reaction mixture in the second reaction zone 11b and the catalyst to be produced after the reaction in the cracking riser 21 are fully mixed, contacted and redistributed, and then passed relative to the second reaction zone 1 The inner conveying pipe 13 with a reduced diameter of 1b enters the third reaction zone 11c, and is connected to the multi-stage reaction cyclone separator 12c in the multi-stage reaction settling section 12b at the top of the third reaction zone 11c for multi-stage reaction separation. After the reaction of the heavy raw material, the oil and gas are output from the top of the multi-stage reaction cyclone separator 12c, and then enter the oil and gas fractionation tower at the bottom of the multi-stage reaction settling vessel 12 through the large oil transfer line, etc.; after the reaction of the heavy raw material, the catalyst containing coke enters the multi-stage reaction stripping section 12a at the bottom of the multi-stage reaction settling vessel 12 from the conveying pipe at the bottom of the multi-stage reaction cyclone separator 12c, and is stripped by the multi-stage reaction. The catalyst to be regenerated after stripping by steam F enters the regeneration unit 3 through the regeneration pipeline 5, contacts with the regeneration air C entering from the bottom of the regeneration unit 3 to undergo an oxidation reaction, and the regenerated flue gas D is output from the top of the regeneration unit 3 to enter the flue gas turbine for further energy recovery and treatment; the high-temperature regenerated catalyst generated by burning the coke enters the catalyst heat exchanger 4 through the regeneration pipeline 6, and converts the low-temperature water vapor G into high-temperature water vapor H after heat extraction. The cooled regenerated catalyst is refluxed to the bottom of the first reaction zone 11a and the bottom of the cracking riser 21 through the regeneration pipeline 6 exiting the catalyst heat exchanger 4 for recycling.

[0104] The remaining operating conditions, product distribution and main properties of gasoline obtained are shown in Table 3.

[0105] Comparative Example 1

[0106] The catalytic cracking device includes the multistage reaction unit 1 used in Example 1 and a conventional cracking unit, the cracking unit uses a conventional riser, does not contain a cracking settler, and the riser is directly connected to a cyclone separator, and the heavy feedstock oil in Table 1 is processed using the catalyst I in Table 2 to produce ultra-low olefin gasoline. The parameters of the multistage reaction unit 1 are the same as those in Example 1, and the riser outlet temperature of the cracking unit is the same as the outlet temperature of the cracking riser 21 in Example 1.

[0107] The remaining operating conditions, product distribution and main properties of gasoline obtained are shown in Table 3.

[0108] Comparative Example 2

[0109] The catalytic cracking device includes the multistage reaction unit 1 described in Example 1, without the cracking reaction unit 2, without refining light hydrocarbons, and using the catalyst I in Table 2 to process the heavy crude oil in Table 1 to produce ultra-low olefin gasoline; the various parameters of the multistage reaction unit 1 are the same as those in Example 1.

[0110] The remaining operating conditions, product distribution and main properties of gasoline obtained are shown in Table 3.

[0111] Comparative Example 3

[0112] The catalytic cracking device includes the multi-stage reaction unit 1 used in Example 1, without the cracking reaction unit 2, without refining light hydrocarbons, and the diameter of the second reaction zone 11b is 0.9 meters, the second reaction zone 11b is not provided with an internal delivery pipe 13, and the remaining parameters of the multi-stage reaction unit 1 are the same as those of Comparative Example 2. The heavy feedstock oil in Table 1 is processed using the catalyst I to produce a low-olefin gasoline operation mode.

[0113] The remaining operating conditions, product distribution and main properties of gasoline obtained are shown in Table 3.

[0114] Example 2

[0115] Compared with Example 1, the catalytic cracking device used in this embodiment is the same as that in Example 1 except that the distribution internal component 14 connecting the first reaction zone 11a and the second reaction zone 11b is a mushroom head type distributor, the catalyst uses the catalyst II in Table 2, and the operating conditions are different. The properties of the raw materials in this embodiment are shown in Table 1, wherein the recycled light gasoline uses light hydrocarbon II as the light raw material, and the recycled light gasoline accounts for 30% of the heavy raw materials, half of which is the light gasoline produced by the device itself, and the other half comes from other devices outside the device.

[0116] The remaining operating conditions, product distribution and main properties of gasoline obtained are shown in Table 3.

[0117] Comparative Example 4

[0118] The catalytic cracking device includes the multistage reaction unit 1 used in Example 1 and a conventional cracking unit, the cracking unit uses a conventional riser, does not contain a cracking settler, and the riser is directly connected to a cyclone separator, and uses the catalyst II in Table 2 to process the heavy feedstock oil in Table 1 to produce more cracked gas. The various parameters of the multistage reaction unit 1 are the same as those in Example 2, and the outlet temperature of the riser of the cracking unit is the same as the outlet temperature of the cracking riser 21 in Example 1.

[0119] The remaining operating conditions, product distribution and main properties of gasoline obtained are shown in Table 3.

[0120] Comparative Example 5

[0121] The catalytic cracking device includes the multi-stage reaction unit 1 used in Example 1, without the cracking reaction unit 2, without recycling light hydrocarbons, using the catalyst II in Table 2 to process the heavy feedstock oil in Table 1, and performing an operation mode of producing more cracked gas. The various parameters of the multi-stage reaction unit 1 are the same as those in Example 2.

[0122] The remaining operating conditions, product distribution and main properties of gasoline obtained are shown in Table 3.

[0123] Comparative Example 6

[0124] The catalytic cracking device includes the multi-stage reaction unit 1 used in Example 1, without the cracking reaction unit 2, without recycling light hydrocarbons, and the diameter of the second reaction zone 11b is 0.9 meters, the internal transport pipe 13 is not set in the second reaction zone 11b, and the remaining parameters of the multi-stage reaction unit 1 are the same as those in Comparative Example 5.

[0125] The remaining operating conditions, product distribution and main properties of gasoline obtained are shown in Table 3.

[0126] Table 1 Raw material properties

[0127] project Heavy raw materials Light hydrocarbons I Light hydrocarbons II <![CDATA[Density (20 °C) kg / m 3 > 0.8954 0.7121 0.7243 Carbon residue value, wt% 2 —— —— Elemental analysis Carbon content, wt% 86.85 86.46 86.67 Hydrogen content, wt% 12.58 13.46 13.22 Sulfur content, wt% 0.37 —— —— Nitrogen content, wt% 0.27 —— —— Hydrocarbon composition analysis Saturated hydrocarbons, wt% 68.24 —— —— Aromatics, wt% 20.09 —— —— Gel, wt% 10.72 —— —— Asphaltene, wt% 0.95 —— —— Ni content, μg / g 4.3 —— —— V content, μg / g 0.3 —— —— PONA,wt% P —— 6 4 I —— 26 13 O —— 49 62 N —— 4 3 A —— 15 18

[0128] Table 2 Catalyst properties

[0129] Main Catalyst Catalyst I Catalyst II Zeolite Type ReHY is the main ZSM-5 is the main Chemical composition, wt% Alumina 46.4 52.1 Sodium oxide 0.22 0.15 Sieve composition, wt% 0~40μm 20.23 25.54 40~80μm 52.12 48.05 >110μm —— 26.41 <![CDATA[Specific surface area / m 2 .g -1 > 165 210 <![CDATA[Deposition density / g.cm -3 > 0.76 0.79 <![CDATA[Apparent density / g·cm -3 > 0.71 0.75 Micro-anti-activity, % 68 58 Sieve composition, wt% 0.38 0.28

[0130] Table 3 Operating conditions and product distribution

[0131]

[0132] As can be seen from Table 3, Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 3 are all in the mode of producing ultra-low olefin gasoline. Example 1 and Comparative Example 1 recycle 30% of light hydrocarbons I, half of which come from olefin-rich light gasoline outside the device; Comparative Example 2 and Comparative Example 3 do not recycle gasoline; Compared with Comparative Example 1, Comparative Example 2 and Comparative Example 3, gasoline olefins in Example 1 are reduced by 2.6, 3.6 and 6.4 percentage points, respectively, and propylene yields are increased by 0.5, 0.7 and 1.1 percentage points, respectively; This shows that the device and method provided by the present invention can significantly reduce the olefin content of gasoline and moderately increase the propylene yield.

[0133] Example 2, Comparative Example 4, Comparative Example 5 and Comparative Example 6 are all operating modes of producing more cracked gas. Example 2 and Comparative Example 4 recycle 30% of light hydrocarbons II, half of which come from olefin-rich light gasoline outside the device; Comparative Example 5 and Comparative Example 6 do not recycle gasoline; Compared with Comparative Example 4, Comparative Example 5 and Comparative Example 6, the gasoline olefins in Example 2 are reduced by 3.3, 11.2 and 13.8 percentage points respectively, and the propylene yield is increased by 1.3, 2.6 and 4.5 percentage points respectively; This shows that the device and method provided by the invention can significantly reduce the olefin content of gasoline and increase the propylene yield.

[0134] The device and method provided by the present invention can promote the reduction of gasoline olefins in the gasoline pool of the entire refinery, and the cracking gas yield is significantly improved. However, for the entire refinery, the yield or output of cracking gas is significantly improved.

[0135] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0136] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations. In addition, the various different embodiments of the present invention can also be combined arbitrarily, as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A catalytic cracking device, characterized in that: The device comprises a multistage reaction unit (1) and a cracking reaction unit (2), wherein the multistage reaction unit (1) comprises a multi-variable diameter riser (11) and a multistage reaction settler (12), and the cracking reaction unit (2) comprises a cracking riser (21) and a cracking settler (23); the multi-variable diameter riser (11) comprises a first reaction zone (11a), a second reaction zone (11b) and a third reaction zone (11c) which are sequentially connected in series along its length direction, the outlet of the third reaction zone (11c) is connected to the multistage reaction settler (12), the inner diameter of the second reaction zone (11b) is larger than the inner diameters of the first reaction zone (11a) and the third reaction zone (11c), and an inner transport pipe (13) extending into the second reaction zone (11b) is provided at the connection between the third reaction zone (11c) and the second reaction zone (11b); The cracking settler (23) comprises a cracking stripping section (23a), a turbulent reaction section (23b) and a cracking settling section (23c) which are sequentially arranged along its length direction; the outlet of the cracking riser (21) is located in the turbulent reaction section (23b); and the cracking stripping section (23a) is provided with a cracking catalyst outlet (25) which is connected to the second reaction zone (11b).

2. The device according to claim 1, characterized in that The ratio of the inner diameter of the inner transport pipe (13) to the inner diameter of the third reaction zone (11c) is 0.9-1.2:1, and the ratio of the length of the inner transport pipe (13) to the second reaction zone (11b) is 0.15-0.8:

1.

3. The device according to claim 1, characterized in that The ratio of the inner diameters of the first reaction zone (11a), the second reaction zone (11b) and the third reaction zone (11c) is 1:2-5:0.7-1.5, and the ratio of their lengths is 1:0.3-2:0.5-2; The ratio of the inner diameters of the turbulent reaction section (23b), the cracking stripping section (23a) and the cracking sedimentation section (23c) is 1:0.4-0.8:2.5-5, and the ratio of the lengths is 1:1.5-3:1.5-4; The ratio of the length of the multi-variable riser (11) to the length of the cracking riser (21) is 1:0.5-1.

2.

4. The device according to claim 1, characterized in that At least one inner delivery hole (13a) is provided on the side wall of the inner delivery pipe (13), and the distance between the inner delivery hole (13a) and the entrance of the third reaction zone (11c) is 0.5-2m.

5. The device according to claim 4, characterized in that The ratio of the total area of ​​at least one of the inner delivery holes (13a) to the cross-sectional area of ​​the inner delivery tube (13) is 0.05-0.3:

1.

6. The device according to any one of claims 1 to 5, characterized in that The second reaction zone (11b) is provided with a distribution internal component (14) connected to the first reaction zone (11a), and the distribution internal component (14) is provided with a plurality of distribution holes (14a).

7. The device according to claim 6, characterized in that The distribution internal component (14) comprises a distribution cylinder (14b) connected to the first reaction zone (11a) and an end distribution plate (14c) connected to the distribution cylinder (14b), the distribution cylinder (14b) and the end distribution plate (14c) are both provided with the distribution holes (14a), and the end distribution plate (14c) is located at one end of the distribution cylinder (14b) away from the first reaction zone (11a).

8. The device according to claim 7, characterized in that The ratio of the sum of the areas of the distribution holes (14a) on the distribution cylinder (14b) to the cross-sectional area of ​​the first reaction zone (11a) is 0.6-4:1; The ratio of the sum of the areas of the distribution holes (14a) on the end distribution plate (14c) to the vertical projection area of ​​the end distribution plate (14c) is 0.1-0.3:

1.

9. The device according to claim 7, characterized in that A side channel (14d) extending to the outside of the distribution tube (14b) is provided at the distribution hole (14a) on the distribution tube (14b), and the opening section of the side channel (14d) away from the distribution tube (14b) is an inclined surface facing the first reaction zone (11a).

10. The device according to claim 7, characterized in that The ratio of the area of ​​the end distribution plate (14c) to the cross-sectional area of ​​the second reaction zone (11b) is 0.7-0.85:

1.

11. The device according to any one of claims 1 to 5, characterized in that The first reaction zone (11a), the second reaction zone (11b), the third reaction zone (11c) and the inner transport pipe (13) are coaxially arranged, and the cracking catalyst outlet (25) is located at the bottom of the cracking stripping section (23a) and is connected to the bottom of the second reaction zone (11b).

12. The device according to any one of claims 1 to 5, characterized in that The multi-variable diameter riser (11) further comprises a multi-stage reaction pre-lift section (11d) connected to the inlet of the first reaction zone (11a); the cracking riser (21) comprises a cracking pre-lift section (21b) and a cracking reaction section (21a) which are sequentially connected in series along its length direction; the outlet of the cracking reaction section (21a) is located at one end of the turbulent reaction section (23b) close to the cracking stripping section (23a); the transition section between the multi-stage reaction pre-lift section (11d) and the first reaction zone (11a) is connected to a multi-stage reaction feed unit (7); and the transition section between the cracking pre-lift section (21b) and the cracking reaction section (21a) is connected to a cracking feed unit (8).

13. The device according to claim 12, characterized in that A cracking distributor (22) is provided at the outlet of the cracking reaction section (21a), and the gas phase outlet of the cracking sedimentation section (23c) is connected to the multi-stage reaction settler (12).

14. The device according to any one of claims 1 to 5, characterized in that The device also includes a regeneration unit (3), the multistage reaction settler (12) is provided with a multistage reaction catalyst outlet (15) connected to the feed inlet of the regeneration unit (3), and the regeneration catalyst outlet (31) of the regeneration unit (3) is connected to the multi-variable riser (11) and / or the cracking riser (21).

15. A catalytic cracking method, characterized in that: Using the device according to any one of claims 1 to 14, the method comprises the following steps: A multi-stage reaction mixture formed by mixing heavy raw materials and a multi-stage reaction catalyst is input from the inlet of the first reaction zone (11a), enters the first reaction zone (11a), the second reaction zone (11b) in sequence, and then enters the third reaction zone (11c) from the inner delivery pipe (13) to undergo a multi-stage catalytic reaction to obtain a multi-stage reactant. The multi-stage reactant is subjected to a multi-stage reaction separation in the multi-stage reaction settler (12) to obtain a multi-stage reaction oil and gas product and a multi-stage reaction catalyst to be produced; A cracking mixture formed by mixing a light raw material and a cracking catalyst is input from the inlet of the cracking riser (21), undergoes a cracking catalytic reaction through the cracking riser (21) to obtain a cracking reactant, and the cracking reactant enters the turbulent reaction section (23b) for a turbulent reaction, is cracked and separated through the cracking settling section (23c), and is cracked and stripped through the cracking stripping section (23a) to obtain a cracked oil and gas product and a cracking catalyst to be produced; The catalyst to be produced by cracking is introduced into the second reaction zone (11b) from the cracking catalyst outlet (25) to be mixed with the multi-stage reaction mixture.

16. The method according to claim 15, characterized in that The inlet temperature of the inner transport pipe (13) is 510-540°C, and the outlet temperature of the cracking riser (21) is 540-620°C.

17. The method according to claim 15, characterized in that The inlet temperature of the inner transport pipe (13) is 550-640°C, and the outlet temperature of the cracking riser (21) is 560-660°C.

18. The method according to any one of claims 15 to 17, characterized in that The residence time of the multi-stage reaction mixture in the first reaction zone (11a) is 0.8-2s, the residence time in the second reaction zone (11b) is 5-15s, and the residence time in the third reaction zone (11c) is 0.5-1.5s; The residence time of the cracking mixture in the cracking riser (21) is 0.8-3.5 seconds, and the residence time in the turbulent reaction section (23b) is 3-13 seconds.

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