Light oil catalytic cracking reaction method and system maintaining thermal balance

Abstract

This application relates to a catalytic cracking reaction method and system. Light oil and regenerated catalyst are transported to a cracking reactor for catalytic cracking. The resulting reaction products are separated. The resulting regenerated catalyst enters a dense phase settling section to continue coking with coking fuel oil. The coked regenerated catalyst is then transported to a regenerator for charring and recycling. The catalytic cracking method of this application improves ethylene and propylene selectivity and reduces methane generation. It also addresses the heat balance issue while maintaining the physical and chemical properties of the catalyst.

Description

Technical Field

[0001] The present application relates to the technical field of fluidized catalytic cracking, and more specifically, to a reaction method and system for catalytic cracking of light oil suitable for maintaining thermal balance. Background Art

[0002] Currently, there is an oversupply of refining capacity, a slowdown in terminal consumption of refined oil products, and an oversupply of refined oil products, which has become an urgent problem for refining companies. In the chemical raw material market, ethylene and propylene, as basic chemical raw materials, remain in strong market demand. The consumption of ethylene and propylene has been increasing year by year. Taking my country as an example, it is estimated that by the end of 2023, my country's ethylene and propylene production capacity will reach approximately 44 million tons / year and 52 million tons / year, respectively, with an average annual compound growth rate of 11.5% and 8.7%, respectively. As a result, the domestic refining landscape and resource flows will undergo structural reorganization, the growth rate of terminal consumption of refined oil products will slow down, and the consumption of light chemical oil will increase significantly. Therefore, the transformation from refining to chemical industry has become an inevitable direction for the development of refineries. Catalytic cracking, as the link between refining and chemical industry, is a key technology in the transformation process from refining to chemical industry.

[0003] Catalytic cracking processes typically use heavy petroleum hydrocarbons as feedstock, particularly paraffin-based vacuum distillates or atmospheric residues, which yield high yields of light olefins such as propylene. With the increasing heaviness and degradation of global crude oil, high-quality heavy petroleum hydrocarbon resources are becoming increasingly scarce, creating an urgent need to expand the feedstock range for catalytic cracking technology. As refineries adjust and transform their product mix, improving oil quality also generates significant amounts of light petroleum hydrocarbons as byproducts. For a typical 10 million ton fuel oil refinery, annual light petroleum hydrocarbon production can reach millions of tons, representing approximately 10% of crude oil processing capacity. For integrated refining and chemical companies or chemical refineries, the production and proportion of light petroleum hydrocarbons will increase significantly as crude oil conversion deepens. Efficiently utilizing these light hydrocarbon resources has become a key focus of research and attention within the refining and chemical industry.

[0004] Catalytic cracking technologies targeting light olefins as their primary target products feature high conversion rates, high reaction temperatures, and high reaction heat. This requires more heat than conventional fluidized bed catalytic regenerators or other catalytic conversion methods. The coke generated by the cracking itself often fails to meet the heat balance requirements of the reaction-regeneration system. Lighter feedstocks exacerbate this problem of insufficient heat sources. When insufficient coke is generated during the reaction, slurry oil recycling or external fuel oil addition to the regenerator are typically used to provide the required heat. Because slurry oil contains a high concentration of polycyclic aromatic hydrocarbons, it readily adsorbs onto the catalyst's active sites, affecting the accessibility of the active sites to the feedstock molecules and, consequently, the catalytic reaction selectivity. Furthermore, because catalytic cracking utilizes molecular sieves as the active component of the catalyst, the localized high temperatures generated by the combustion of fuel oil within the regenerator cause the aluminum in the molecular sieve framework to gradually dislodge, leading to irreversible damage to the catalyst. This fundamentally addresses the impact of the high-temperature hotspots generated by the localized combustion of external fuel oil on the catalyst's skeletal structure and reaction performance. In order to solve this problem, the existing technical solutions all start from the regenerator system, such as setting up an oxygen-depleted area in the regenerator, introducing fuel oil into the oxygen-depleted area to mix with the catalyst, and then entering the regenerator for burning and regeneration; or arranging a heater in the regenerator and using a fuel nozzle, the fuel nozzle is constructed to spray a mixture of fuel and oxygen-containing gas for combustion to supplement heat; or injecting methane, relying on the combustion heat of methane to supplement heat for the reaction. The heat supplementation method in the above technology has alleviated the adverse effects of the catalyst, but it has not fundamentally solved the impact of the high-temperature hot spots generated by the local combustion of the external fuel oil on the catalyst skeleton structure and reaction performance, thereby seriously affecting the reaction selectivity. Therefore, in the development of light oil catalytic cracking technology, while improving the selectivity of low-carbon olefins, insufficient heat balance is also a technical problem that must be solved. Summary of the Invention

[0005] The purpose of this application is to provide a light oil catalytic cracking reaction method and system that maintains thermal balance, thereby increasing the yield of ethylene and propylene, solving the problem of thermal balance during the reaction process from the reaction aspect, and improving the selectivity of the catalytic reaction.

[0006] The present application provides a catalytic cracking reaction-regeneration system, comprising:

[0007] Catalytic cracking reactor,

[0008] Oil separation equipment,

[0009] settler, and

[0010] Regenerator,

[0011] The cracking reactor is provided with a pre-lift gas inlet at the bottom, a catalyst inlet, one or more cracking feedstock inlets, and an oil agent outlet at the top; the oil agent outlet of the cracking reactor is in fluid communication with the oil agent separation device, so that the reaction oil gas from the catalytic cracking reactor and the regenerated catalyst are separated in the oil agent separation device;

[0012] The settler is configured to collect the spent catalyst separated in the oil separation device; and the settler is provided with a sidewall regenerated catalyst inlet and a dense phase settling section, wherein the sidewall regenerated catalyst inlet is located above the dense phase settling section; the dense phase settling section is provided with a sidewall coking fuel oil inlet, a coking fuel oil feed distributor and a spent catalyst outlet at the bottom;

[0013] The regenerator is provided with an inlet for catalyst to be regenerated, a first regenerated catalyst outlet and a second regenerated catalyst outlet; the first regenerated catalyst outlet is fluidically connected to the catalyst inlet of the cracking reactor, so that at least a portion of the regenerated catalyst is circulated back to the cracking reactor; the second regenerated catalyst outlet is fluidically connected to the regenerated catalyst inlet on the side wall of the settler, so that at least a portion of the regenerated catalyst is circulated back to the settler for coking reaction; the inlet for catalyst to be regenerated is fluidically connected to the outlet for catalyst to be regenerated of the settler, so that the carbonized catalyst of the settler enters the regenerator for regeneration.

[0014] In one embodiment, the dense phase sedimentation section is provided with a feed annular distributor, and the side wall coking fuel oil inlet is provided on the feed annular distributor; the distance between the feed annular distributor and the bottom of the dense phase sedimentation section is 2 / 3 to 3 / 4 of the height of the dense phase sedimentation section.

[0015] In one embodiment, the feed annular distributor is provided with 2-8 evenly distributed upward inclined holes, and the axes of the inclined holes converge at the same intersection of the central axial line of the settler.

[0016] In one embodiment, the catalytic cracking reactor comprises, from bottom to top:

[0017] optional pre-lift zone;

[0018] A reaction zone, the reaction zone comprising at least one reduced-diameter reaction section, the reduced-diameter reaction section being in the form of a hollow cylinder with a substantially circular cross-section and open bottom and top ends, the inner diameter of which decreases continuously or discontinuously from bottom to top; and

[0019] export zone;

[0020] wherein the optional pre-lifting zone is connected to the bottom end of the reaction zone, the top end of the reaction zone is connected to the outlet zone, and at least one raw material feed port is provided on the optional pre-lifting zone and / or the bottom end of the reaction zone;

[0021] The cross-sectional inner diameter of the bottom end of the reaction zone is greater than or equal to the cross-sectional inner diameter of the optional pre-lifting zone, and the cross-sectional inner diameter of the top end is equal to or smaller than the cross-sectional inner diameter of the optional pre-lifting zone and the cross-sectional inner diameter of the outlet zone; the regenerated catalyst inlet is provided at the bottom of the reaction zone and / or the optional pre-lifting zone.

[0022] In one embodiment, the ratio of the inner diameter of the bottom cross-section of the reaction zone of the catalytic cracking reactor to the total height of the catalytic cracking reactor is 0.01:1 to 0.5:1; the ratio of the total height of the reaction zone to the total height of the catalytic cracking reactor is 0.15:1 to 0.8:1.

[0023] In one embodiment, the reaction zone of the catalytic cracking reactor includes 1-3 reduced diameter reaction sections.

[0024] Preferably, the reduced diameter reaction section of the catalytic cracking reactor is in the form of a hollow truncated cone, and the longitudinal section is an isosceles trapezoid; the ratio of the inner diameter of the top cross-section to the height of the reduced diameter reaction section is independently 0.005-0.3:1, the ratio of the inner diameter of the bottom cross-section to the height of the reduced diameter reaction section is independently 0.015-0.25:1, and the ratio of the inner diameter of the bottom cross-section to the inner diameter of the top cross-section is independently greater than 1.2 and less than or equal to 10; the ratio of the height of the reduced diameter reaction section to the total height of the catalytic cracking reactor is independently 0.15:1 to 0.8:1.

[0025] In one embodiment, the ratio of the inner diameter to the height of the pre-lift zone of the catalytic cracking reactor is 0.02-0.4:1; and the ratio of its height to the total height of the catalytic cracking reactor is 0.01:1 to 0.2:1.

[0026] In one embodiment, the pre-lifting zone of the catalytic cracking reactor is connected to the reaction zone by a first connecting section, the longitudinal section of the first connecting section is an isosceles trapezoid, and the outward inclination angle α of the side of the isosceles trapezoid is 5-85°.

[0027] In one embodiment, the ratio of the inner diameter of the cross section of the reactor outlet zone to the height is 0.01-0.3:1, and the ratio of the height of the outlet zone to the total height of the reactor is 0.05:1 to 0.5:1.

[0028] The present application also provides a light oil catalytic cracking method for maintaining thermal balance, characterized in that the method comprises:

[0029] 1) Preheated light oil is introduced from the bottom of the cracking reactor, contacts with the regenerated catalyst from the regenerator and performs catalytic cracking reaction from bottom to top. The resulting oil mixture is introduced into the oil separation equipment for separation to obtain reaction products and catalyst to be regenerated.

[0030] 2) The catalyst to be generated enters the dense phase settling section below the settler and undergoes a coking reaction with the coking fuel oil introduced from the upper part of the dense phase settling section to obtain reaction oil gas and carbonized catalyst, wherein the reaction oil gas enters the oil agent separation device for separation to obtain reaction products.

[0031] 3) The carbonized catalyst is transported to the regenerator for char regeneration, and the resulting regenerated catalyst is circulated to the cracking reactor and the settling section of the settler.

[0032] In one embodiment, the light oil includes gaseous hydrocarbons and light distillate oil; preferably, the properties of the light oil meet one, two, three or four of the following indicators: density at 20°C is less than 860 kg / m3, residual carbon is 0-0.5% by weight, total aromatic hydrocarbon content is 0%-30% by weight, and the end distillation point is less than 360°C.

[0033] In one embodiment, the conditions of the catalytic cracking reaction include: a reaction temperature of 510-750°C, a reaction time of 0.5-10 seconds, a catalyst-oil weight ratio of 10:1 to 50:1, a weight ratio of pre-lift gas to feed oil of 0.05:1 to 2.0:1, a catalyst density of 20-100 kg / m3, a linear velocity of 4-18 m / s, and a reaction pressure of 130-450 kPa.

[0034] In one embodiment, the method further comprises introducing a C4 hydrocarbon fraction and / or a C5-C6 light gasoline fraction into the cracking reactor for catalytic cracking reaction.

[0035] In one embodiment, the conditions of the coking reaction include: a reaction temperature of 460-650°C, a reaction time of 2-20 seconds, a catalyst-oil weight ratio of 3:1 to 30:1, a fluidizing gas to coking fuel oil weight ratio of 0.01:1 to 0.2:1, and a catalyst particle density of 300-450 kg / m3.

[0036] In one embodiment, the method is carried out in the catalytic cracking reaction-regeneration system of the present application.

[0037] In the present application, the reduced diameter reaction section set in the cracking reactor, especially the reduced diameter structure of the conical reaction section, is conducive to accelerating the reaction oil and gas to leave the reaction zone, shortening the reaction time, and reducing the catalyst backmixing, which is conducive to reducing the secondary conversion reaction of the light olefins generated by the primary reaction and improving the selectivity of light olefins.

[0038] In the present application, the stripping section of the traditional catalytic cracking unit is eliminated, and the original stripping section space is used as a coking reaction site. The characteristic that the catalyst to be generated still has a relatively high cracking reaction activity is utilized, and suitable reaction conditions are provided for the coking fuel oil. The coking raw oil reacts with the catalyst under relatively low temperature and oxygen-free fluidized conditions to cause a coking reaction, so that the coke adheres to the catalyst and is then transported to the regeneration system. Under the action of high temperature and oxygen-rich gas, it is fully burned to release heat, supplying the heat required for the reaction without damaging the properties of the catalyst. This realizes the replenishment of the coke source from the reaction system end and solves the heat balance problem of the catalytic cracking unit.

[0039] When the method and system of this application are used in catalytic cracking reactions, the contact efficiency between the feedstock and the catalyst is high, the catalytic reaction selectivity is good, the yield of high-value-added products such as ethylene and propylene is high, and the yield of byproducts such as methane is low. This helps refineries transform, develop, and expand from oil refining to chemical raw material production, solving the problem of petrochemical raw material shortages and improving the economic benefits of refineries. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings are used to provide a further understanding of the present application and constitute a part of the specification. Together with the following detailed description, they are used to explain the present application but do not constitute a limitation of the present application. In the accompanying drawings:

[0041] Figure 1 A schematic diagram of an embodiment of a catalytic cracking reactor of the present application;

[0042] Figure 2 A schematic diagram of a catalytic cracking system according to an embodiment of the present application. DETAILED DESCRIPTION

[0043] The present application will be further described in detail below through the accompanying drawings and examples, through which the features and advantages of the present application will become more clear and distinct.

[0044] The word "exemplary" is used exclusively herein to mean "serving as an example, example, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.

[0045] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0046] Any specific numerical value disclosed herein (including the endpoints of a numerical range) is not limited to the exact value of the numerical value, but should be understood to also include values ​​close to the exact value, such as all possible values ​​within ±5% of the exact value. Moreover, for a disclosed numerical range, any combination of the endpoints of the range, between the endpoints and the specific points in the range, and between the specific points can be used to generate one or more new numerical ranges, and these new numerical ranges should also be considered to be specifically disclosed herein.

[0047] In this application, the terms "upstream" and "downstream" are used in relation to the direction of flow of the reactants. For example, when the reactants flow from bottom to top, "upstream" refers to a position below, while "downstream" refers to a position above.

[0048] Unless otherwise specified, the terms used herein have the same meaning as commonly understood by those skilled in the art. If a term is defined herein and its definition is different from the commonly understood meaning in the art, the definition herein shall prevail.

[0049] The present application provides a light oil catalytic cracking method for maintaining thermal balance, the method comprising:

[0050] 1) Preheated light oil is introduced from the bottom of the cracking reactor, contacts with the regenerated catalyst from the regenerator and performs catalytic cracking reaction from bottom to top. The resulting oil mixture is introduced into the oil separation equipment for separation to obtain reaction products and catalyst to be regenerated.

[0051] 2) The catalyst to be generated enters the dense phase settling section below the settler and undergoes a coking reaction with the coking fuel oil introduced from the upper part of the dense phase settling section to obtain reaction oil gas and carbonized catalyst, wherein the reaction oil gas enters the oil agent separation device for separation to obtain reaction products.

[0052] 3) The carbonized catalyst is transported to the regenerator for char regeneration, and the resulting regenerated catalyst is circulated to the cracking reactor and the settling section of the settler.

[0053] Figure 2 A catalytic cracking reaction-regeneration system capable of implementing this method is shown. The catalytic cracking method of the present invention is further described below in conjunction with this catalytic cracking reaction-regeneration system. The following description of the catalytic cracking method of the present invention is also applicable to the catalytic cracking reaction-regeneration system of the present invention, and vice versa.

[0054] The catalytic cracking reaction-regeneration system comprises:

[0055] Catalytic cracking reactor 100,

[0056] Oil separation equipment 201,

[0057] settler 200, and

[0058] Regenerator 500.

[0059] like Figure 1 As shown, the catalytic cracking reactor 100 can be provided with a pre-lift gas inlet 101, one or more cracking feed oil inlets (e.g., a cracking feed feed inlet 102 at the bottom, a C4 hydrocarbon fraction and / or C5-C6 light gasoline fraction inlet 105, etc.), a catalyst inlet 103 at the bottom, and an oil agent outlet 104 at the top. The oil agent outlet 104 of the cracking reactor is in fluid communication with the oil agent separation device 201, so that the first reaction oil gas and the first spent catalyst from the catalytic cracking reactor 100 are separated in the oil agent separation device 201.

[0060] In one embodiment, the catalytic cracking reactor 100 includes, from bottom to top:

[0061] Optional pre-lift zone I,

[0062] Reaction zone II, wherein the reaction zone II includes at least one reduced-diameter reaction section, wherein the reduced-diameter reaction section is a hollow cylinder with a substantially circular cross-section and open bottom and top ends, and the inner diameter of the hollow cylinder decreases continuously or discontinuously from bottom to top; and

[0063] Export Zone III,

[0064] The optional pre-elevation zone I is connected to the bottom end of the reaction zone II, the top end of the reaction zone II is connected to the outlet zone III, and at least one raw material feed port 102 is provided on the optional pre-elevation zone and / or the bottom end of the reaction zone;

[0065] The cross-sectional inner diameter of the bottom end of the reaction zone II is greater than or equal to the cross-sectional inner diameter of the optional pre-lift zone I, and the cross-sectional inner diameter of the top end is equal to or less than the cross-sectional inner diameter of the optional pre-lift zone and the cross-sectional inner diameter of the outlet zone.

[0066] like Figure 1 As shown, the catalytic cracking reactor may include the pre-lifting zone I, which is arranged at the bottom of the catalytic cracking reactor and is used to pre-lift the catalyst entering the reactor. Figure 1As shown, a catalyst inlet 103 is provided at the lower part of the pre-lifting zone I for inputting the catalyst. The pre-lifting zone I can be a hollow cylindrical structure, and the ratio of its inner diameter to height is 0.02-0.4:1; the ratio of its height to the total height of the reactor is 0.01:1 to 0.2:1, preferably 0.05:1 to 0.15:1. In one embodiment, the inner diameter of the pre-lifting zone I can be 0.2-5 meters, preferably 0.4-3 meters. In an embodiment in which a pre-lifting zone I is present, a pre-lifting medium can be input into the pre-lifting zone I through a pre-lifting gas inlet 101. In an embodiment in which a pre-lifting zone I is present, at least one catalyst inlet 103 can also be provided at the bottom of the pre-lifting zone I for allowing the catalyst to pass through the pre-lifting zone I into the reactor.

[0067] According to the present application, the pre-lift zone I is not necessary. For example, when the reaction zone II of the reactor of the present application is used in series with other reactors such as a riser reactor, the reaction zone II can be directly connected to the outlet of the other reactor located upstream without the need to use the pre-lift zone I. In one embodiment, the catalytic cracking reactor may not include the pre-lift zone I. At this time, the bottom of the reaction zone II may be provided with at least one raw material feed port 102 to facilitate the entry of raw materials and the like into the catalytic cracking reactor. In an embodiment in which there is no pre-lift zone I, the bottom of the reaction zone II may be provided with at least one catalyst inlet (not shown) for allowing the catalyst to enter the reactor. Of course, the reaction zone II may not be provided with a catalyst inlet, and the catalyst therein may be derived from the catalyst carried in the logistics of other reactors. Both embodiments are within the scope of protection of the present application.

[0068] like Figure 1 As shown, the catalytic cracking reactor may include a reaction zone II. A pre-lift zone I is connected to the bottom end 110 of the reaction zone II, and the top end 120 of the reaction zone II is connected to the outlet zone III. At least one catalyst inlet 103 and at least one raw material feed port 102 are provided on the pre-lift zone and / or at the bottom of the reaction zone. The inner diameter of the cross section of the bottom end 110 of the reaction zone II is greater than or equal to the inner diameter of the cross section of the pre-lift zone I, and the inner diameter of the cross section of the top end 120 is equal to or less than the inner diameter of the cross section of the pre-lift zone I and the inner diameter of the cross section of the outlet zone III.

[0069] In the catalytic cracking reactor provided in the present application, the reaction zone II is a fluidized bed. Preferably, the fluidized bed is one or a combination of a transport fluidized bed, a turbulent fluidized bed and a fast bed.

[0070] In one embodiment, the pre-elevation zone I is connected to the reaction zone II via a first transition section I-1. The longitudinal section of the first transition section I-1 may be an isosceles trapezoid, and the outward inclination angle α of the side of the isosceles trapezoid may be 5-85°, preferably 15-75°.

[0071] like Figure 1 As shown, the raw material feed port can be provided at the upper portion of the pre-elevation zone I, in the first transition section I-1, or at the lower portion of the reaction zone II. In particular, in an embodiment where the pre-elevation zone I is not present, a raw material feed port 102 can be provided at the lower portion of the reaction zone II for feeding raw materials.

[0072] In one embodiment, the ratio of the inner diameter of the bottom cross-section of the reaction zone II to the total height of the reactor is 0.01:1 to 0.5:1, preferably 0.05:1 to 0.2:1; the ratio of the total height of the reaction zone II to the total height of the reactor is 0.15:1 to 0.8:1, for example 0.2:1 to 0.75:1.

[0073] like Figure 1 As shown, the reaction zone II includes at least one diameter-reducing reaction section, which is a hollow cylinder with a roughly circular cross-section and open bottom and top ends, and its inner diameter decreases continuously or discontinuously from bottom to top.

[0074] In this application, "reduced diameter" refers to a decrease in inner diameter in a discontinuous manner, such as steps or jumps, or in a continuous manner. An example of a "reduced diameter section with a discontinuous decrease in inner diameter from bottom to top" includes a column consisting of two or more hollow cylinders with decreasing inner diameters.

[0075] For example, the reaction zone II may be cylindrical, including one or more hollow truncated cone sections, or may be cylindrical, including two or more hollow cylindrical sections. According to the present application, when the reaction zone includes two or more reduced diameter reaction sections, the reduced diameter reaction sections may have the same or different heights, and this application does not impose strict restrictions on this.

[0076] In a preferred embodiment, the reaction zone II comprises a cylindrical form consisting of one or more hollow truncated conical segments and optional connecting segments for connecting adjacent hollow truncated conical segments, or a cylindrical form consisting of two or more hollow cylindrical segments and optional connecting segments for connecting adjacent hollow cylindrical segments.

[0077] In one embodiment, Figure 1 As shown, the reaction zone II includes a reduced diameter reaction section, which is in the form of a hollow truncated cone, and its longitudinal section is an isosceles trapezoid; the inner diameter D of the top cross section is 120 The height h of the reduced diameter reaction section IIThe ratio is 0.005-0.3:1 independently, and the inner diameter D of the bottom cross section 110 The height h of the reduced diameter reaction section II The ratio is 0.015-0.25:1 independently, and the inner diameter of the bottom cross section D 110 and the inner diameter D of the top cross section 120 The ratio of each is independently greater than 1.2 and less than or equal to 10, more preferably 1.5 to 5; the diameter reduction reaction section h II The ratio of the height of the bottom end to the total height h of the reactor is 0.15:1 to 0.8:1, preferably 0.2:1 to 0.75:1. In one embodiment, the inner diameter D of the bottom cross section is 110 The ratio of the height h1 of the reduced diameter reaction section to the total height h of the reactor is 0.01:1 to 0.5:1, preferably 0.05:1 to 0.2; the ratio of the height h1 of the reduced diameter reaction section to the total height h of the reactor is 0.15:1 to 0.8:1, preferably 0.2:1 to 0.75:1, and the total height h1 of the reaction zone II is 0.15:1 to 0.8:1, preferably 0.2:1 to 0.75:1. II The ratio of the inner diameter D of the top cross section of the reduced diameter reaction section 100 to the total height h of the reactor is 0.15:1 to 0.8:1, preferably 0.2:1 to 0.75:1. 110 In one embodiment, the total height h of the reaction zone II is 0.2-5 meters, preferably 0.4-3 meters. II It may be about 2-50 meters, preferably about 5-40 meters, and more preferably about 8-20 meters.

[0078] In the catalytic cracking reactor of the present application, the reduced-diameter reaction section, especially the conical reaction section, has a large bottom space, which can effectively increase the catalyst density in the reactor, thereby greatly increasing the ratio of catalyst to reaction raw materials in the reactor, strengthening the primary cracking reaction of the raw materials, not only improving the reaction conversion rate, but also increasing the yield of light olefins; moreover, the reduced-diameter reaction section, especially the reduced-diameter structure of the conical reaction section, is conducive to accelerating the reaction oil and gas to leave the reaction zone, shortening the reaction time, and reducing catalyst backmixing, which is conducive to reducing the secondary conversion reaction of the light olefins generated by the primary reaction and improving the selectivity of light olefins.

[0079] In the catalytic cracking reactor provided herein, the reactor may be provided with one or more, for example, one, two or more, raw material feed ports, and the one or more raw material feed ports may be independently provided at the outlet end of the pre-elevation zone I, or at the bottom of the reaction zone II. Further preferably, the positions of the multiple raw material inlets are independently located at the same height or at different heights of the reaction zone II. Thus, raw materials of different properties can be fed separately at different raw material feed ports.

[0080] like Figure 1As shown, the catalytic cracking reactor may include an outlet zone III. In one embodiment, the outlet zone III may be in the form of a hollow cylinder with a cross-sectional inner diameter and a height h III The ratio is 0.01-0.3:1, the height h of the outlet area III The ratio to the total height h of the reactor is 0.05: 1 to 0.5: 1, more preferably 0.1: 1 to 0.35: 1. In one embodiment, the inner diameter of the outlet zone III is 0.2-5 meters, preferably 0.4-3 meters.

[0081] As mentioned above, the inner diameter of the cross section at the top of reaction zone II is equal to or smaller than the inner diameter of the cross section of outlet zone III. In one embodiment, the inner diameter of the cross section at the top of reaction zone II is equal to the inner diameter of the cross section of outlet zone III.

[0082] In one embodiment, the inner diameter of the cross section at the top of reaction zone II is smaller than the inner diameter of the cross section of outlet zone III. In this case, reaction zone II and outlet zone III may be connected by a third transition section (not shown). The longitudinal section of the third transition section may be an isosceles trapezoid, and the outward inclination angle of the side of the isosceles trapezoid may be 5-85°, preferably 15-75°.

[0083] The outlet end 104 of the outlet zone III may be directly connected to the inlet of the oil separation device 201 , such as a cyclone separator.

[0084] In one embodiment, the light oil used in this application includes gaseous hydrocarbons and light distillate oil. The properties of the light oil meet one, two, three, or four of the following indicators: density at 20°C less than 860 kg / m3, carbon residue 0-0.5% by weight, total aromatics content 0%-30% by weight, and end-of-range boiling point less than 360°C.

[0085] In one embodiment, the gaseous hydrocarbons can be selected from a mixture of one or more of saturated liquefied gas, unsaturated liquefied gas, and C4 fractions; the light distillate oil includes petroleum hydrocarbons, oxygen-containing compounds, and distillate oils generated from biomass or waste plastics with a distillation range of 25 to 360°C; the petroleum hydrocarbons can be selected from a mixture of one or more of primary processed straight-run naphtha, straight-run kerosene, and straight-run diesel; and a mixed oil of one or more of secondary processed topped oil, raffinate oil, hydrocracked light naphtha, pentane oil, coker gasoline, Fischer-Tropsch synthetic oil, catalytic cracking light gasoline, hydrogenated gasoline, and hydrogenated diesel.

[0086] In one embodiment, the catalyst comprises, on a dry basis and based on the dry weight of the catalyst, 1-50 wt%; 5-99 wt% inorganic oxide, and 0-70 wt% clay. The zeolite comprises a medium-pore zeolite and an optional large-pore zeolite, wherein the medium-pore zeolite is selected from the group consisting of ZSM series zeolites, ZRP zeolites, and any combination thereof; and the large-pore zeolite is selected from the group consisting of rare earth Y-type zeolites, rare earth hydrogen Y-type zeolites, ultrastable Y-type zeolites, and high-silica Y-type zeolites, and any combination thereof. On a dry basis, the medium-pore zeolite accounts for 10-100 wt%, preferably 50-90 wt%, of the total weight of the zeolite.

[0087] In the present application, the medium-pore zeolite and large-pore zeolite are defined in accordance with conventional definitions in the art, that is, the average pore diameter of the medium-pore zeolite is about 0.5-0.6 nm, and the average pore diameter of the large-pore zeolite is about 0.7-1.0 nm.

[0088] As an example, the large-pore zeolite can be selected from one or more of rare earth Y (REY) type zeolite, rare earth hydrogen Y (REHY) type zeolite, ultrastable Y type zeolite obtained by different methods, and high silicon Y type zeolite. The medium-pore zeolite can be selected from zeolites with MFI structure, such as ZSM series zeolites and / or ZRP zeolites. Optionally, the above-mentioned medium-pore zeolites can also be modified with non-metallic elements such as phosphorus and / or transition metal elements such as iron, cobalt, and nickel. A more detailed description of ZRP zeolite can be found in U.S. Patent No. 5,232,675A. ZSM series zeolites are preferably selected from a mixture of one or more of ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38, ZSM-48 and other zeolites of similar structures. A more detailed description of ZSM-5 can be found in U.S. Patent No. 3,702,886A.

[0089] According to the present application, the inorganic oxide as a binder is preferably silicon dioxide (SiO2) and / or aluminum oxide (Al2O3). The clay as a matrix (ie, a carrier) is preferably kaolin and / or halloysite.

[0090] In one embodiment, the catalytic cracking reaction conditions include: a reaction temperature of 550-750°C, a reaction time of 0.5-10 seconds, a catalyst-to-oil weight ratio of 10:1 to 50:1, a pre-lift gas to feedstock weight ratio of 0.05:1 to 2.0:1, a catalyst density of 20-100 kg / m³, a linear velocity of 4-18 m / s, and a reaction pressure of 130-450 kPa. In one embodiment, the pre-lift gas is selected from water vapor, nitrogen, dry gas, rich gas, or C4 fraction, or a mixture thereof.

[0091] In one embodiment, the feedstock oil is introduced into the cracking reactor at one location, or the feedstock oil is introduced into the cracking reactor at more than one location, which may be the same or different.

[0092] In one embodiment, the method further comprises introducing a C4 hydrocarbon fraction and / or a C5-C6 light gasoline fraction into the cracking reactor for catalytic cracking reaction.

[0093] In this application, the C4 hydrocarbon fraction refers to low-molecular-weight hydrocarbons that exist in gaseous form at room temperature and pressure and have the C4 fraction as a main component, including alkanes, alkenes, and alkynes with 4 carbon atoms in their molecules. It can include both gaseous hydrocarbon products rich in the C4 hydrocarbon fraction produced by the method of the present invention (e.g., liquefied gas) and gaseous hydrocarbons rich in the C4 fraction produced by other devices. The C4 hydrocarbon fraction produced by the method of the present invention is preferred. The C4 hydrocarbon fraction is preferably a C4 hydrocarbon fraction rich in olefins, and the C4 olefin content can be greater than 50% by weight, preferably greater than 60% by weight, and more preferably greater than 70% by weight.

[0094] In the present application, the C5-C6 light gasoline fraction may include the pyrolysis gasoline produced by the method of the present invention, or may include gasoline fractions produced by other devices, for example, at least one C5-C6 fraction selected from catalytic pyrolysis gasoline, catalytic cracking gasoline, straight-run gasoline, coker gasoline, thermal pyrolysis gasoline, thermal cracking gasoline, and hydrogenated gasoline. The C5-C6 light gasoline is preferably an olefin-rich fraction, wherein the olefin content is greater than 50% by weight, preferably greater than 60% by weight.

[0095] In one embodiment, C4 hydrocarbons or C5-C6 light gasoline fraction is introduced into the cracking reactor at one or more locations downstream.

[0096] In the present application, the oil separation device 201 is used to separate the reaction products and catalyst from the oil from the catalytic cracking reactor 100. The oil separation device 201 is connected to the outlet port 104 of the catalytic cracking reactor. The oil separation device 201 can be a cyclone separator or an outlet rapid separator.

[0097] In the present application, the settler 200 is configured to collect the regenerated catalyst separated in the oil-agent separation device 201. Furthermore, the settler 200 is provided with a sidewall regenerated catalyst inlet 201 and a dense phase settling section 205, wherein the sidewall regenerated catalyst inlet 201 is located above the dense phase settling section 205. The dense phase settling section 205 is provided with a sidewall coking fuel oil inlet 208, a coking fuel oil feed distributor 209, and a bottom regenerated catalyst outlet 206. A fluidizing gas inlet 207 is also provided at the bottom of the dense phase settling section 205 for introducing a fluidizing gas to fluidize the catalyst in the dense phase settling section. The fluidizing gas can be nitrogen, water vapor, or a mixture thereof.

[0098] In the present application, a dense phase settling section 205 is provided at the lower portion of the settler 200 for introducing the green coking fuel oil into the dense phase settling section 205 .

[0099] In one embodiment, the reaction conditions in the dense phase settling section 205 include: a reaction temperature of 460-650°C, a reaction time of 2-20 seconds, a fluidizing gas to coking fuel oil weight ratio of (0.01-0.2):1, and a catalyst bed density of 300-450 kg / m³. In one embodiment, the amount of coking fuel oil injected can be 10-50% of the total weight of the feedstock introduced into the catalytic cracking reactor.

[0100] In one embodiment, the coking fuel oil is a mixture of pyrolysis heavy oil produced by the device and secondary processed distillate oil, or a mixture thereof. Preferably, the secondary processed distillate oil can be selected from a mixture of one or more of catalytic cracking diesel, catalytic cracking diesel, coker gasoline, straight run diesel and coker diesel.

[0101] In one embodiment, the dense phase settling section 205 is provided with a horizontally arranged green coking fuel oil annular feed distributor 209, which is configured to distribute the green coking fuel oil input through one or more green coking fuel oil inlets provided on the side wall of the settler.

[0102] In one embodiment, the feed distributor 209 is disposed in the lower middle portion of the dense phase settling section, and the distance between the feed distributor and the bottom of the dense phase settling section is independently 2 / 3 to 3 / 4 of the height of the coking fuel oil inlet.

[0103] In one embodiment, the feed distributor 209 is provided with 2-8 evenly distributed upward inclined holes, and the axes of the inclined holes converge at the same intersection of the central axial line of the settler.

[0104] In one embodiment, a certain proportion of regenerated catalyst is introduced into the dense phase settling section of the settler, and the regenerated catalyst is introduced from one or more positions above the dense phase settling section. The proportion of regenerated catalyst introduced into the dense phase settling section of the settler can be adjusted as needed, for example, it can account for 5-20 wt% of the total regenerated catalyst based on the total weight of the total regenerated catalyst.

[0105] The regenerator 500 is used to regenerate the regenerated catalyst. Its lower portion is equipped with an oxygen-containing gas inlet 501, a regenerated catalyst inlet 505, and two regenerated catalyst outlets 506 and 508. A flue gas outlet 504 is located at the top. The first regenerated catalyst outlet 506 is in fluid communication with the catalyst inlet 103 of the cracking reactor, allowing at least a portion of the regenerated catalyst to be recycled back to the cracking reactor. The second regenerated catalyst outlet 508 is in fluid communication with the regenerated catalyst inlet 210 on the sidewall of the settler, allowing at least a portion of the regenerated catalyst to be recycled back to the settler for coking. The regenerated catalyst inlet 505 is in fluid communication with the regenerated catalyst outlet 206 of the settler, allowing the carbonized catalyst in the settler to enter the regenerator for regeneration.

[0106] In one embodiment, the catalytic cracking reactor and the settler are generally arranged in parallel at different heights.

[0107] In the catalytic cracking system of the present application, there may be one or more catalytic cracking reactors, a combination of one catalytic cracking reactor of the present application and another existing catalytic cracking reactor, or a combination of multiple catalytic cracking reactors of the present application. These reactors may be connected in parallel and connected to the oil-agent separation device.

[0108] In the catalytic cracking system provided herein, the settler, oil-agent separation device, regenerator, reaction product separation device, and the like can all be devices well known to those skilled in the art, and the connections between these devices can also be made using methods known in the art. For example, the oil-agent separation device can include a cyclone separator and an outlet rapid separator.

[0109] The catalytic cracking method and system of the present application can efficiently produce chemical raw materials such as ethylene and propylene from light petroleum hydrocarbons. It can not only fundamentally solve the problem of heat balance, but also reduce the damage caused to the catalyst and regeneration system by the traditional method of spraying combustion oil, saving catalyst costs, and helping refineries to transform, develop and extend from oil refining to chemical raw material production, which not only solves the problem of shortage of petrochemical raw materials, but also improves the economic benefits of refineries.

[0110] The present application will be further described below with reference to the preferred embodiments shown in the accompanying drawings, but the present application is not limited thereby.

[0111] Figure 2 A preferred embodiment of the catalytic cracking reaction system of the present application is given.

[0112] The pre-lift gas enters the pre-lift zone I of the cracking reactor from the bottom of the cracking reactor 100 through the pre-lift gas inlet 101. The high-temperature regenerated catalyst from the regenerator enters the pre-lift zone I at the bottom of the cracking reactor 100 through the regenerated catalyst inlet 103, mixes with the pre-lift gas, and moves upward. It contacts the feedstock oil from the feedstock oil inlet 102 and undergoes a catalytic cracking reaction in the reaction zone II. The carbonized catalyst and the oil and gas generated by the reaction flow upward, enter the outlet zone III, and enter the oil agent separation device 201 through the outlet 104.

[0113] The reaction oil and gas separated by the oil agent separation device 201 enter the gas collection chamber 202 and are introduced into the product separation system (not shown) through the oil and gas pipeline 203; the separated catalyst to be regenerated enters the dense phase settling section 205, and the regenerated catalyst is introduced into the dense phase settling section 205 through the side wall regeneration catalyst inlet 210; the coking fuel oil is introduced into the feed distribution pipe 204 through the coking fuel oil inlet 208, and is injected into the dense phase settling section 205 through the nozzle, where it contacts the catalyst to be regenerated and undergoes a coking reaction. The reacted catalyst to be regenerated enters the regenerator 500; the oxygen-containing gas inlet 501 The oxygen-containing gas enters the regenerator after passing through the gas distributor 502, contacts the coke-containing catalyst, causes a complete combustion reaction, and completely releases heat. Part of the regenerated catalyst is returned to the settling section 205 of the catalytic cracking reactor through the second regenerated catalyst outlet 508 and the side wall regenerated catalyst inlet 210 for recycling, and part of the catalyst is sent to the catalytic cracking reactor through the regenerated catalyst outlet 506 and the regenerated catalyst inlet 103 for reaction use; the regenerated flue gas is recovered through the cyclone separator 503 to remove the entrained catalyst, and then sent to the subsequent energy recovery system through the flue gas outlet 504.

[0114] Example

[0115] The following examples further illustrate the present invention but are not intended to limit the present invention. The catalyst used in the experiments was an industrial catalyst with the trade name NCC. The cracking reaction feedstock was Yanshan straight-run naphtha obtained from the Yanshan Petrochemical atmospheric and vacuum unit. The coking fuel oil was catalytic diesel obtained from the Anqing Petrochemical catalytic cracking unit. The properties of the two feedstocks are shown in Table 1.

[0116] Example 1

[0117] according to Figure 2 The system was tested: the structure of the catalytic cracking reactor used is as follows:

[0118] The total height of the reactor is 10 meters, of which the pre-lifting zone is 2 meters and the inner diameter is 0.2 meters; the reaction zone is 5 meters high, the inner diameter of the top cross section is 0.2 meters, and the inner diameter of the bottom cross section is 0.3 meters; the outlet zone is 3 meters high and has an inner diameter of 0.2 meters.

[0119] The structure of the settler is as follows:

[0120] The distance between the annular feed distributor and the bottom of the dense phase settling section is 2 / 3 of the height of the dense phase settling section;

[0121] A regenerated catalyst inlet is provided above the dense phase settling section.

[0122] The cracking reaction of straight-run naphtha is carried out in the cracking reactor. The preheated raw oil is introduced from the lower part of the cracking reactor, contacts the regenerated catalyst from the regenerator and undergoes a catalytic cracking reaction from bottom to top to obtain an oil mixture of the reaction product and the regenerated catalyst. The oil mixture enters the cyclone separator from the reactor outlet, and the reaction product and the regenerated catalyst are quickly separated. The reaction product is cooled and collected.

[0123] The regenerated catalyst enters the dense phase settling section under the action of gravity. The bottom fluidizing steam creates a turbulent fluidization state. Anqing slurry (i.e., coking fuel oil) is then injected into the dense phase settling section, where it comes into contact with the regenerated catalyst to initiate a coking reaction. The coked, carbonized catalyst is then transported to the regenerator for regeneration by contact with air. A portion of the regenerated catalyst is returned to the catalytic cracking reactor for recycling, while a portion is recycled back to the dense phase settling section. The regenerated catalyst recycled back to the dense phase settling section accounts for 10% of the weight of the regenerated catalyst recycled back to the catalytic cracking reactor. The operating conditions and product distribution are listed in Table 2.

[0124] From the results in Table 2, it can be seen that the methane yield is 14.43%, the ethylene yield is 18.07% by weight, the propylene yield is 18.68% by weight, the coke yield is 6.35%, the methane selectivity is 16.99%, and the total selectivity of ethylene and propylene is 43.29%.

[0125] Comparative Example 1

[0126] according to Figure 2 The test was conducted in a system in which green coking fuel oil was not injected into the dense phase settling section.

[0127] A cracking reaction test of straight-run naphtha was carried out in a catalytic cracking reactor. Preheated feedstock oil was introduced from the lower part of the cracking reactor, contacted with the regenerated catalyst from the regenerator, and a catalytic cracking reaction was carried out from bottom to top to obtain an oil-agent mixture of reaction products and the regenerated catalyst. The oil-agent mixture entered a cyclone separator from the reactor outlet, and the reaction products and the regenerated catalyst were quickly separated. The reaction products were cooled and collected.

[0128] The spent catalyst is collected by gravity in the dense phase settling section and then directly enters the regenerator via a standpipe. It is regenerated by contact with air and then returned to the catalytic cracking reactor for recycling. The operating conditions and product distribution are listed in Table 2.

[0129] The results in Table 2 show that the methane yield was 14.76%, the ethylene yield was 18.01% by weight, the propylene yield was 18.40% by weight, the coke yield was 3.92%, the methane selectivity was 17.62%, and the combined ethylene and propylene selectivity was 43.46%. The coke yield in this comparative example was low, and the coke produced was insufficient to maintain the thermal balance of the reaction.

[0130] It can be seen from the results of the above examples that the catalytic cracking reaction system of the present application can not only reduce the methane yield and improve the selectivity of ethylene and propylene, but also produce coke with high selectivity, providing a heat source for the regenerator from the reaction system without affecting the regeneration system.

[0131] In the description of this application, it should be noted that the terms "upper", "lower", "inside", "outside", "front", "back", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships in the working state of this application. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on this application.

[0132] In the description of this application, it should be noted that, unless otherwise specified or limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0133] The present application has been described above in conjunction with preferred embodiments, but these embodiments are merely exemplary and serve only as an illustrative example. On this basis, various replacements and improvements can be made to the present application, all of which fall within the scope of protection of the present application.

[0134] Table 1 Properties of cracking reaction raw materials and coking fuel oil

[0135] Straight-run naphtha Anqing slurry <![CDATA[Density at 20 °C, kg / m 3 > 752.5 1068.6 Refractive index at 70℃ 1.6361 <![CDATA[Viscosity at 100°C, millimeters 2 / second]]> 11.5 Carbon residue, % (weight) 0 4.79 Carbon content, % (weight) 87.47 91.22 Hydrogen content, % (weight) 14.53 8.06 Sulfur content, % (weight) 0.014 0.331 Nitrogen content, mg / kg 1.2 2100 Basic nitrogen, mg / kg / 86 Distillation range, ℃ 5% (volume) / 364.5 10% (volume) 90.9 373.2 30% (volume) 121.7 400.6 50% (volume) 145.8 425.6 70% (volume) 167.3 464.8 95% (volume) 197.5 /

[0136] Table 2 Operating conditions and results of Example 1 and Comparative Example 1

[0137]

Claims

1. A catalytic cracking reaction-regeneration system comprising: Catalytic cracking reactor, Oil separation equipment, settler, and Regenerator, The catalytic cracking reactor is provided with a pre-lift gas inlet at the bottom, a catalyst inlet, one or more cracked feedstock inlets, and an oil agent outlet at the top, wherein the catalytic cracking reactor includes a reaction zone, the reaction zone includes at least one reduced diameter reaction section, the reduced diameter reaction section is a hollow cone with a substantially circular cross-section and open bottom and top ends, and its inner diameter decreases continuously or discontinuously from bottom to top; the oil agent outlet of the catalytic cracking reactor is in fluid communication with the oil agent separation device, so that the reaction oil gas and the catalyst to be regenerated from the catalytic cracking reactor are separated in the oil agent separation device; The settler is configured to collect the regenerated catalyst separated in the oil-agent separation device; and the settler is provided with a sidewall regenerated catalyst inlet and a dense phase settling section, wherein the sidewall regenerated catalyst inlet is located above the dense phase settling section; the dense phase settling section is provided with a sidewall coking fuel oil inlet, a coking fuel oil feed distributor and a regenerated catalyst outlet at the bottom, wherein a fluidizing gas inlet is further provided at the bottom of the dense phase settling section for introducing a fluidizing gas, so that the catalyst in the dense phase settling section is in a turbulent fluidized state; The regenerator is provided with an inlet for catalyst to be regenerated, a first regenerated catalyst outlet and a second regenerated catalyst outlet; the first regenerated catalyst outlet is fluidically connected to the catalyst inlet of the catalytic cracking reactor, so that at least a portion of the regenerated catalyst is circulated back to the catalytic cracking reactor; the second regenerated catalyst outlet is fluidically connected to the regenerated catalyst inlet on the side wall of the settler, so that at least a portion of the regenerated catalyst is circulated back to the settler for coking reaction; the inlet for catalyst to be regenerated is fluidically connected to the outlet for catalyst to be regenerated of the settler, so that the carbonized catalyst of the settler enters the regenerator for regeneration.

2. The catalytic cracking reaction-regeneration system according to claim 1, wherein: The dense phase sedimentation section is provided with a feed annular distributor, and the side wall coking fuel oil inlet is arranged on the feed annular distributor; the distance between the feed annular distributor and the bottom of the dense phase sedimentation section is 2 / 3 to 3 / 4 of the height of the dense phase sedimentation section.

3. The catalytic cracking reaction-regeneration system according to claim 2, wherein: The feed annular distributor is provided with 2-8 evenly distributed upward inclined holes, and the axes of the inclined holes converge at the same intersection of the central axial lines of the settler.

4. The catalytic cracking reaction-regeneration system according to claim 1, wherein: The catalytic cracking reactor comprises, from bottom to top, optional pre-lift zone; A reaction zone, the reaction zone comprising at least one reduced-diameter reaction section, the reduced-diameter reaction section being in the form of a hollow cylinder with a substantially circular cross-section and open bottom and top ends, the inner diameter of which decreases continuously or discontinuously from bottom to top; and export zone; wherein the optional pre-lifting zone is connected to the bottom end of the reaction zone, the top end of the reaction zone is connected to the outlet zone, and at least one raw material feed port is provided on the optional pre-lifting zone and / or the bottom end of the reaction zone; The cross-sectional inner diameter of the bottom end of the reaction zone is greater than or equal to the cross-sectional inner diameter of the optional pre-lifting zone, and the cross-sectional inner diameter of the top end is equal to or smaller than the cross-sectional inner diameter of the optional pre-lifting zone and the cross-sectional inner diameter of the outlet zone; the regenerated catalyst inlet is provided at the bottom of the reaction zone and / or the optional pre-lifting zone.

5. The catalytic cracking reaction-regeneration system according to claim 4, wherein: The ratio of the inner diameter of the bottom cross section of the reaction zone of the catalytic cracking reactor to the total height of the catalytic cracking reactor is 0.01:1 to 0.5:1; the ratio of the total height of the reaction zone to the total height of the catalytic cracking reactor is 0.15:1 to 0.8:

1.

6. The catalytic cracking reaction-regeneration system according to claim 4, characterized in that: The reaction zone of the catalytic cracking reactor includes 1 to 3 reduced diameter reaction sections.

7. The catalytic cracking reaction-regeneration system according to claim 6, characterized in that: The reduced diameter reaction section of the catalytic cracking reactor is in the form of a hollow truncated cone, and its longitudinal section is an isosceles trapezoid; the ratio of the inner diameter of its top cross-section to the height of the reduced diameter reaction section is independently 0.005-0.3:1, the ratio of the inner diameter of the bottom cross-section to the height of the reduced diameter reaction section is independently 0.015-0.25:1, and the ratio of the inner diameter of the bottom cross-section to the inner diameter of the top cross-section is independently greater than 1.2 and less than or equal to 10; the ratio of the height of the reduced diameter reaction section to the total height of the catalytic cracking reactor is independently 0.15:1 to 0.8:

1.

8. The catalytic cracking reaction-regeneration system according to claim 4, characterized in that: The ratio of the inner diameter to the height of the pre-lift zone of the catalytic cracking reactor is 0.02-0.4:1; and the ratio of the height of the pre-lift zone to the total height of the catalytic cracking reactor is 0.01:1 to 0.2:

1.

9. The catalytic cracking reaction-regeneration system according to claim 8, characterized in that: The pre-lift zone of the catalytic cracking reactor is connected to the reaction zone by a first connecting section, the longitudinal section of the first connecting section is an isosceles trapezoid, and the outward inclination angle α of the side of the isosceles trapezoid is 5-85 o .

10. The catalytic cracking reaction-regeneration system according to claim 4, characterized in that: The ratio of the inner diameter of the cross section of the outlet zone of the catalytic cracking reactor to the height is 0.01-0.3:1, and the ratio of the height of the outlet zone to the total height of the catalytic cracking reactor is 0.05:1 to 0.5:

1.

11. A method for catalytic cracking of light oil while maintaining thermal balance, characterized in that: The method includes: 1) The preheated light oil is introduced from the lower part of the catalytic cracking reactor, contacts with the regenerated catalyst from the regenerator and undergoes catalytic cracking reaction from bottom to top. The resulting oil-agent mixture is introduced into the oil-agent separation equipment for separation to obtain the reaction product and the catalyst to be regenerated. 2) The catalyst to be generated enters the dense phase settling section at the lower part of the settler and reacts with the coking fuel oil introduced from the upper part of the dense phase settling section to generate coking oil gas and carbonized catalyst, wherein the reaction oil gas enters the oil agent separation device for separation to obtain reaction products. 3) The carbonized catalyst is transported to the regenerator for charring and regeneration, and a portion of the regenerated catalyst is recycled to the catalytic cracking reactor and a portion is recycled to the dense phase settling section. The method is carried out in the catalytic cracking reaction-regeneration system according to any one of claims 1 to 10.

12. The method according to claim 11, wherein The light oil includes gaseous hydrocarbons and light distillate oil.

13. The method according to claim 12, wherein: The properties of the light oil meet one, two, three or four of the following indicators: density at 20°C is less than 860 kg / m3, residual carbon is 0-0.5% by weight, total aromatic hydrocarbon content is 0%-30% by weight, and final distillation point is less than 360°C.

14. The method according to claim 11, wherein The conditions for the catalytic cracking reaction include: a reaction temperature of 510-750°C, a reaction time of 0.5-10 seconds, a catalyst-to-oil weight ratio of 10:1 to 50:1, a weight ratio of pre-lift gas to feedstock oil of 0.05:1 to 2.0:1, a catalyst density of 20-100 kg / m3, a linear velocity of 4-18 m / s, and a reaction pressure of 130-450 kPa.

15. The method according to claim 11, characterized in that The method further comprises introducing a C4 hydrocarbon fraction and / or a C5-C6 light gasoline fraction into the catalytic cracking reactor for a catalytic cracking reaction.

16. The method according to claim 11, wherein The coking reaction conditions include: reaction temperature of 460-650°C, reaction time of 2-20 seconds, catalyst-oil weight ratio of 3:1 to 30:1, fluidizing gas to coking fuel oil weight ratio of 0.01:1 to 0.2:1, and catalyst particle density of 300-450 kg / m3.

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