Catalytic cracking reactor, catalytic cracking system and method

Abstract

The application relates to a catalytic cracking reactor, a catalytic cracking system and a method, the catalytic cracking reactor comprising, from bottom to top, an optional pre-lifting zone, a reaction zone, the reaction zone comprising at least one reduced-diameter reaction section, and an outlet zone. The catalytic cracking reactor and system of the application can be used to efficiently produce chemical raw materials such as ethylene and propylene from light petroleum hydrocarbons, helping refineries to transform, develop and extend from oil refining to chemical raw material production, solving the problem of shortage of petrochemical raw materials and improving the economic benefits of the refineries. When the reactor and system of the application are used for catalytic cracking reaction, the contact efficiency of raw materials and catalysts is high, the selectivity of catalytic reaction is good, the yield of high-value-added products such as ethylene and propylene is high, and the yield of by-products such as methane is low.

Description

Technical Field

[0001] This application relates to the field of petrochemicals, and more specifically, to a catalytic cracking reactor, a catalytic cracking system, and a method. Background Technology

[0002] Ethylene and propylene are the most basic raw materials for petrochemicals and the foundation for producing various important organic chemical products. The production scale, output, and technological level of ethylene and propylene are important indicators of a country's petrochemical industry development level. Although my country's ethylene production capacity and output rank second in the world, and its propylene production capacity and output rank first, they still cannot meet the needs of my country's national economic development and the improvement of people's living standards. In 2020, my country's equivalent demand for ethylene and propylene was 58.63 million tons and 47.5 million tons, respectively. Based on equivalent demand, the self-sufficiency rates for ethylene and propylene were approximately 51.4% and 79.9%, respectively, and olefin production still fell short of demand. Currently, steam cracking of naphtha and other light hydrocarbons remains the main production technology for ethylene and propylene. To achieve the required cracking temperature, the cracking furnaces use fossil fuels to heat the furnace tubes, making the steam cracking furnace a major source of carbon dioxide emissions, with high energy consumption, poor product selectivity, and the generation of large amounts of methane. In view of this, researchers have been developing catalytic cracking technology for olefins from naphtha and other light hydrocarbons.

[0003] CN201510296090.8 discloses a method for converting naphtha, which combines naphtha catalytic cracking with steam cracking of low-carbon alkanes and catalytic cracking of high-carbon alkanes and high-carbon olefins to produce low-carbon olefins, light aromatics, and high-octane gasoline. Since most reactants are converted in the relatively low-temperature catalytic cracking process, overall energy consumption can be reduced.

[0004] CN201910080462.1 discloses a feedstock conversion device containing naphtha, comprising reacting naphtha-containing feedstock in a fast fluidized bed reactor to obtain product gas and catalyst to be regenerated; then, part of the stripped catalyst to be regenerated is fed to the fast fluidized bed reactor, and part is fed into a regenerator. The technical problem solved by this device is to reduce the impact of thermal cracking reaction in naphtha catalytic cracking technology and reduce the yield of methane in the product.

[0005] CN 201811440380.5 discloses a process for producing propylene and co-producing aromatics via low-temperature catalytic reaction using naphtha or light hydrocarbons as raw materials. The raw material, naphtha or light hydrocarbons, is heated by a heat exchanger and / or a furnace before entering a fixed-bed reactor. Under the action of a specific catalyst, a low-temperature catalytic reaction is carried out. The reaction products are separated by a separation system to obtain ethylene, propylene, C4 and C5 hydrocarbons, and byproducts such as toluene and xylene, among other aromatics. A portion of the C4 and C5 hydrocarbons are recycled back to the reactor.

[0006] CN201910201885.4 discloses a combined reactor for alkane dehydrogenation and catalytic cracking of hydrocarbons to produce olefins. The disclosed reactor for catalytic dehydrogenation and cracking of alkane to produce olefins includes a reactor for catalytic dehydrogenation and cracking, and a settling section. The settling section is located at the top of the reactor. The reactor includes a dehydrogenation reaction section and a cracking reaction section, with the dehydrogenation reaction section located below the cracking reaction section. One end of a catalyst regeneration inclined tube is connected to the dehydrogenation reaction section. This method is beneficial to both the dehydrogenation reaction and the catalytic cracking reaction.

[0007] Compared to steam cracking, naphtha fixed-bed catalytic cracking is characterized by a lower reaction temperature, but it has a lower conversion rate for low-carbon alkanes. Combining naphtha catalytic cracking with steam cracking can improve ethylene yield to some extent, but carbon emissions remain a concern. Combining it with alkane dehydrogenation is a promising technological approach, but the mechanism by which dehydrogenation and cracking complement each other in terms of catalysts and process technology is still under investigation.

[0008] Naphtha and other light feedstocks have small molecules and high activation energies, requiring high reaction temperatures. This often leads to high methane yields as a byproduct, and the catalytic cracking reaction generates significant heat, requiring a large amount of heat to achieve the desired reaction. The coke produced during cracking often fails to meet the heat balance requirements of the reaction-regeneration system. The low coke production during catalytic cracking of naphtha and other light hydrocarbons necessitates large amounts of external fuel oil. Because catalytic cracking uses molecular sieves as the active component of the catalyst, the localized high temperatures generated by fuel oil combustion in the regenerator cause aluminum to gradually leach from the molecular sieve framework, gradually decreasing catalyst activity and further reducing reactant conversion rates. Therefore, catalytic cracking technology for naphtha and other light feedstocks needs continuous improvement and development to achieve higher reaction conversion rates and selectivity. The existing technologies mentioned above propose methods and catalysts for converting petroleum hydrocarbon feedstocks into low-carbon olefins through catalytic cracking, but they fail to address the problems of insufficient heat of reaction and high methane yields during the cracking of light feedstocks. Summary of the Invention

[0009] The purpose of this application is to provide a catalytic cracking reactor, system, and method to improve the selectivity of the catalytic cracking reaction of light feedstocks to produce ethylene and propylene, reduce the methane yield, and solve the problem of insufficient heat in the catalytic cracking reaction of light feedstocks.

[0010] This application provides a catalytic cracking reactor, characterized in that the catalytic cracking reactor comprises, from bottom to top:

[0011] Optional pre-promotion area

[0012] The reaction zone includes at least one diameter-reducing reaction section, which is a hollow cylinder with a generally circular cross-section and open at the bottom and top, its inner diameter decreasing continuously or discontinuously from bottom to top; and

[0013] Export area

[0014] The optional pre-lifting zone is connected to the bottom of the reaction zone, the top of the reaction zone is connected to the outlet zone, and at least one raw material inlet is provided on the optional pre-lifting zone and / or at the bottom of the reaction zone.

[0015] The inner diameter of the cross-section at the bottom of the reaction zone is greater than or equal to the inner diameter of the cross-section of the optional pre-lifting zone, and the inner diameter of the cross-section at the top is equal to or less than the inner diameter of the cross-section of the optional pre-lifting zone and the inner diameter of the cross-section of the outlet zone.

[0016] One or more reaction directing agent inlets are provided downstream of the reaction zone, and the distance between the one or more reaction directing agent inlets and the outlet end of the reaction zone is 0 to 20% of the total height of the reaction zone.

[0017] In one embodiment, the ratio of the bottom cross-sectional inner diameter of the reaction zone to the total height of the 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 reactor is 0.15:1 to 0.8:1.

[0018] In one embodiment, the reaction zone includes 1-3 diameter-reducing reaction sections.

[0019] In one embodiment, the reduced-diameter reaction section is in the form of a hollow truncated cone with an isosceles trapezoidal longitudinal section; 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 its 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 reactor is independently 0.15:1 to 0.8:1.

[0020] In one embodiment, the inner diameter of the top cross-section of each of the diameter-reducing reaction sections is independently 0.2-5 meters.

[0021] In one embodiment, the ratio of the inner diameter to the height of the pre-lifting zone is 0.02-0.4:1; and the ratio of its height to the total height of the reactor is 0.01:1 to 0.2:1.

[0022] In one embodiment, the inner diameter of the pre-lifting zone is 0.2-5 meters.

[0023] In one embodiment, the pre-lifting zone and the reaction zone are connected by a first connecting section, the longitudinal section of which is an isosceles trapezoid with an outward inclination angle α of 5-85° on the side of the isosceles trapezoid.

[0024] In one embodiment, the ratio of the cross-sectional inner diameter to the height of the outlet zone 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.

[0025] In one embodiment, the cross-sectional inner diameter of the outlet area is 0.2-5 meters.

[0026] This application also provides a catalytic cracking system, which includes a catalytic cracking reaction device, an oil separation device, a stripping device, an optional reaction product separation device, and a regenerator, characterized in that the catalytic cracking reaction device includes one or more catalytic cracking reactors of this application.

[0027] In one embodiment, at least one fuel oil inlet is provided in the lower part of the stripping unit and / or in the connecting pipeline between the stripping unit and the regenerator.

[0028] In one embodiment, at least one fuel oil inlet is provided at the lower part of the stripping device.

[0029] The distance between each fuel oil inlet and the bottom of the stripping device is independently 0-30% of the height of the stripping device.

[0030] In one embodiment, the oil separation device includes a settling device arranged coaxially or at different heights with the catalytic cracking reactor.

[0031] This application also provides a catalytic cracking method, including the step of bringing reactants and catalysts into contact and reacting in the catalytic cracking system described above in this application.

[0032] In one embodiment, the reaction raw materials are selected from light feedstock oils of C4-C20.

[0033] In one embodiment, a reaction directing agent is introduced into the catalytic cracking reactor through a reaction directing agent inlet. The reaction directing agent is selected from water and petroleum distillate oil, and the petroleum distillate oil is selected from one or more of gasoline distillate, diesel distillate, wax oil distillate, and slurry oil.

[0034] In one embodiment, the feed weight ratio of the reaction directing agent to the reaction raw material is 0.03-0.3:1.

[0035] In one embodiment, at least one fuel oil inlet is provided in the lower part of the stripping unit of the catalytic cracking system and / or in the connecting pipeline between the stripping unit and the regenerator.

[0036] The method includes: injecting fuel oil through the fuel oil inlet, so that the stripped catalyst and fuel oil enter the regenerator for regeneration.

[0037] In one embodiment, the temperature of the regenerated catalyst after regeneration by the regenerator is 680-780°C.

[0038] In the catalytic cracking reactor of this application, the large bottom space of the narrowed reaction section, especially the conical reaction section, can effectively increase the catalyst density in the reactor, thereby significantly increasing the ratio of catalyst to reactants in the reactor, enhancing the primary cracking reaction of the reactants, improving not only the reaction conversion rate but also the yield of low-carbon olefins. Moreover, the narrowed structure of the narrowed reaction section, especially the conical reaction section, facilitates the acceleration of the reaction oil and gas leaving the reaction zone, shortens the reaction time, and reduces catalyst backmixing, which helps to reduce the secondary conversion reaction of low-carbon olefins generated in the primary reaction and improves the selectivity of low-carbon olefins.

[0039] In the catalytic cracking reactor provided in this application, a reaction directing agent can be injected downstream of the reaction zone, effectively improving the temperature distribution within the reactor and thus altering the cracking reaction process, achieving the technical effect of reducing methane emissions. Furthermore, when the directing agent is petroleum distillate oil, petroleum hydrocarbons also serve as a supplementary fuel oil, helping to improve the thermal balance.

[0040] In the catalytic cracking system provided in this application, fuel oil can be injected into the lower part of the stripper, so that the fuel oil forms additional coke on the catalyst. After entering the regenerator, it can be evenly distributed in the catalyst bed and stably and uniformly combusted and released heat under the action of oxygen-containing gas. This achieves synergistic control of fuel oil distribution and coking on the catalyst, avoids local hot spots, and effectively protects the performance of the catalyst.

[0041] The catalytic cracking reactor and system of this application can efficiently produce chemical feedstocks such as ethylene and propylene from light petroleum hydrocarbons, helping refineries transform, develop, and extend their operations from oil refining to chemical feedstock production. This not only solves the problem of petrochemical feedstock shortages but also improves the economic efficiency of refineries. When the reactor 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 by-products such as methane is low. Attached Figure Description

[0042] The accompanying drawings are provided to further illustrate the present application and form part of the specification. They are used together with the following detailed description to explain the present application, but do not constitute a limitation thereof. In the drawings:

[0043] Figure 1This is a schematic diagram of a catalytic cracking reactor according to one embodiment of the present application.

[0044] Figure 2 A schematic diagram of a catalytic cracking reactor according to another embodiment of this application.

[0045] Figure 3 This is a schematic diagram of a catalytic cracking system according to one embodiment of the present application.

[0046] Figure 4 A schematic diagram of a catalytic cracking system according to another embodiment of this application. Detailed Implementation

[0047] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. Through these descriptions, the features and advantages of the present application will become clearer and more apparent.

[0048] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0049] Any specific numerical values ​​disclosed herein (including the endpoints of numerical ranges) are not limited to their exact values, but should be understood to also include values ​​close to the exact value, such as all possible values ​​within ±5% of the exact value. Furthermore, with respect to the disclosed numerical ranges, one or more new numerical ranges can be obtained by arbitrarily combining the endpoint values ​​of the range, the endpoint values ​​with specific point values ​​within the range, and the specific point values ​​themselves; these new numerical ranges should also be considered as specifically disclosed herein.

[0050] In this application, the terms "upstream" and "downstream" refer to the direction of reaction material flow. For example, when the reaction material flows from bottom to top, "upstream" refers to the position located at the bottom, while "downstream" refers to the position located at the top.

[0051] Unless otherwise stated, the terms used herein have the same meaning as commonly understood by those skilled in the art, and if a term is defined herein and its definition differs from the common understanding in the art, the definition herein shall prevail.

[0052] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0053] like Figure 1 and Figure 2 As shown, this application provides a catalytic cracking reactor, which comprises, from bottom to top:

[0054] Optional pre-lifting zone I,

[0055] Reaction zone II, comprising at least one diameter-reducing reaction section, wherein the diameter-reducing reaction section is a hollow cylinder with a generally circular cross-section and open at the bottom and top, and its inner diameter decreases continuously or discontinuously from bottom to top; and

[0056] Export Zone III

[0057] The optional pre-lifting zone I is connected to the bottom of the reaction zone II, the top of the reaction zone II is connected to the outlet zone III, and at least one raw material inlet 9 is provided on the optional pre-lifting zone and / or the bottom of the reaction zone.

[0058] The inner diameter of the cross-section at the bottom of the reaction zone II is greater than or equal to the inner diameter of the cross-section of the optional pre-lifting zone I, and the inner diameter of the cross-section at the top is equal to or less than the inner diameter of the cross-section of the optional pre-lifting zone and the inner diameter of the cross-section of the outlet zone.

[0059] One or more reaction directing agent inlets 10 are provided downstream of the reaction zone II, and the distance between the one or more reaction directing agent inlets 10 and the outlet end of the reaction zone II is 0 to 20% of the total height of the reaction zone.

[0060] like Figure 1 and Figure 2 As shown, the catalytic cracking reactor may include the pre-lifting zone I, which is located at the bottom of the catalytic cracking reactor and is used to pre-lift the catalyst, etc., entering the reactor. Figure 1 and Figure 2 As shown, a catalyst inlet 110 is provided at the lower part of the pre-lifting zone I for introducing catalyst. The pre-lifting zone I can be a hollow cylindrical structure with an inner diameter to height ratio of 0.02-0.4:1 and a height to total reactor height ratio of 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 embodiments with a pre-lifting zone I, a pre-lifting medium can be introduced into the pre-lifting zone I through a pre-lifting medium pipeline 8. In embodiments with a pre-lifting zone I, at least one catalyst inlet 110 can also be provided at the bottom of the pre-lifting zone I for allowing the catalyst to enter the reactor through the pre-lifting zone I.

[0061] According to this application, the pre-lift zone I is not mandatory. For example, when the reaction zone II of the reactor of this application is used in series with other reactors, such as riser reactors, the reaction zone II can be directly connected to the outlet of the other reactor located upstream, without the need for the pre-lift zone I. In one embodiment, the catalytic cracking reactor may not include the pre-lift zone I. In this case, the bottom of the reaction zone II may be provided with at least one feed inlet 9 to facilitate the entry of raw materials into the catalytic cracking reactor. In embodiments where the pre-lift zone I is absent, the bottom of the reactor II may be provided with at least one catalyst inlet (not shown) to allow the catalyst to enter the reactor. Of course, the reactor II may also not be provided with a catalyst inlet, and the catalyst therein may be derived from the catalyst carried in the stream of other reactors. Both of these embodiments are within the scope of protection of this application.

[0062] like Figure 1 and Figure 2 As shown, the catalytic cracking reactor may include a reaction zone II. A pre-lifting zone I is connected to the bottom 210 of the reaction zone II, and the top 220 of the reaction zone II is connected to the outlet zone III. At least one catalyst inlet 21 and at least one feed inlet 9 are provided on the pre-lifting zone and / or at the bottom of the reaction zone. The inner diameter of the cross-section of the bottom 210 of the reaction zone II is greater than or equal to the inner diameter of the cross-section of the pre-lifting zone I, and the inner diameter of the cross-section of the top 220 is equal to or less than the inner diameter of the cross-section of the pre-lifting zone I and the inner diameter of the cross-section of the outlet zone III.

[0063] In the catalytic cracking reactor provided in this application, the reaction zone II is a fluidized bed, preferably a combination of one or more of a transport fluidized bed, a turbulent fluidized bed, and a fast bed.

[0064] In one embodiment, the pre-lifting zone I and the reaction zone II are connected by a first transition section I-1. The longitudinal section of the first transition section I-1 can be an isosceles trapezoid, and the outward inclination angle α of the side of the isosceles trapezoid can be 5-85°, preferably 15-75°.

[0065] like Figure 1 As shown, the raw material inlet 9 can be located in the upper part of the pre-lifting zone I, in the first transition section I-1, or in the lower part of the reaction zone II. In particular, in embodiments where the pre-lifting zone I is absent, the lower part of the reactor II can be provided with the raw material inlet 9 for feeding raw materials.

[0066] In one embodiment, the ratio of the bottom cross-sectional inner diameter 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.

[0067] In the reactor of this application, reaction zone II is provided with one or more reaction directing agent inlets 10 near the outlet. More preferably, each of the reaction directing agent inlets 10 is independently located at a position 0 to 20% from the outlet end of the reaction zone, more preferably at a position 0% to 10% from the outlet end of the reaction zone. Figure 1 and 2 As shown, the distance L between the one or more reaction directing agent inlets 10 and the outlet end 220 of the reaction zone II is... 10 Each of the total height h of the reaction zone is independent. II 0% to 20%, for example, 0% to 10%.

[0068] Injecting a reaction directing agent downstream of the reaction zone of the catalytic cracking reactor can effectively improve the temperature distribution within the reactor, thereby altering the cracking reaction process and achieving the technical effect of reducing methane emissions. In one embodiment, the reaction directing agent can be selected from water and petroleum distillate oil, wherein the petroleum distillate oil is selected from one or more of gasoline distillate, diesel distillate, wax oil distillate, and slurry oil. Furthermore, when the directing agent is petroleum distillate oil, petroleum hydrocarbons also serve to supplement the fuel oil, helping to improve the thermal balance.

[0069] like Figure 1 and Figure 2 As shown, the reaction zone II includes at least one diameter-reducing reaction section, which is a hollow cylinder with a generally circular cross-section and open at the bottom and top, and whose inner diameter decreases continuously or discontinuously from bottom to top.

[0070] According to this application, "diameter reduction" refers to a decrease in the inner diameter in a discontinuous manner, such as a step-like or abrupt manner, or a continuous manner. As an example of "a diameter reduction segment with a discontinuous decrease in inner diameter from bottom to top", a column composed of two or more segments with decreasing inner diameters can be cited.

[0071] As an example, the reaction zone II can be a cylindrical shape comprising one or more hollow truncated conical segments, or a cylindrical shape comprising two or more hollow cylindrical segments. According to this application, when the reaction zone comprises two or more reduced-diameter reaction segments, each reduced-diameter reaction segment can have the same or different heights; this application does not impose strict limitations on this.

[0072] 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.

[0073] In one embodiment, the reaction zone II includes 1-3 diameter-reduction reaction sections, for example, 1 diameter-reduction reaction section 100 (e.g., Figure 1 As shown), for example, two series-connected narrowing reaction sections 100 and 100' (as shown). Figure 2 (As shown), for example, three series-connected narrowing reaction sections.

[0074] In one implementation, such as Figure 1 As shown, the reaction zone II includes a narrowed reaction section 100, which is in the shape of a hollow truncated cone, and its longitudinal section is an isosceles trapezoid; the inner diameter D of its top cross-section is... 220 With the height h1 of the diameter-reducing reaction section (in) Figure 1 In the middle, h1 and h II The ratios of the equal parts are each independent and range from 0.005 to 0.3:1. The inner diameter D of the bottom cross-section... 210 The ratio of the height h1 of the reduced-diameter reaction section to the height h1 of the reduced-diameter reaction section is independently 0.015-0.25:1, and the inner diameter D of the bottom cross-section is... 210 With the inner diameter D of the top cross section 220 The ratio of each is independently greater than 1.2 and less than or equal to 10, more preferably 1.5 to 5; the ratio of the height of the narrowed reaction section h1 to the total height h of the reactor is independently 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 210 The ratio of the height h1 of the reactor 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 one or more narrowing reaction sections to the total height h of the reactor is independently 0.15:1 to 0.8:1, preferably 0.2:1 to 0.75:1, and the total height h of the reaction zone II is... II The ratio of the reactor's height to its total height h 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 top cross-section of the narrowed reaction section 100 is... 210 The height is 0.2-5 meters, preferably 0.4-3 meters. In one embodiment, the total height h of the reaction zone II is... II It can be about 2-50 meters, preferably about 5-40 meters, and more preferably about 8-20 meters.

[0075] In one implementation, such as Figure 2As shown, the reaction zone II includes two series-connected narrowed reaction sections 100 and 100'. Both narrowed reaction sections 100 and 100' are hollow truncated cones with an isosceles trapezoidal longitudinal section; the inner diameter D of their apex cross-section... 220 D 220’ The ratios of the heights h1 and h1' of the reduced-diameter reaction section are each independently 0.005-0.3:1, and the inner diameter D of the bottom cross-section... 210 D 210’ The ratios of the heights h1 and h1' of the reduced-diameter reaction section are each independently 0.015-0.25:1, and the inner diameter D of the bottom cross-section... 210 D 210’ With the inner diameter D of the top cross section 220 D 220’ The ratio of each is independently greater than 1.2 and less than or equal to 10, more preferably 1.5 to 5; the ratio of the height of the narrowed reaction sections h1 and h1' to the total height h of the reactor is independently 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... 210 D 220’ The ratio of the height h1 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, h1' of the one or more narrow-diameter reaction sections to the total height h of the reactor is independently 0.15:1 to 0.8:1, preferably 0.2:1 to 0.75:1, and the total height h of the reaction zone II is... II The ratio of the reactor height to the total reactor height h 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 top cross-section of the narrowed reaction sections 100, 100' is... 210 D 210’ Each of the individual zones has a height of 0.2-5 meters, preferably 0.4-3 meters. In one embodiment, the total height h of the reaction zone II is... II It can be about 2-50 meters, preferably about 5-40 meters, and more preferably about 8-20 meters.

[0076] In one embodiment, the reduced-diameter reaction sections 100 and 100' are connected by a second transition section II-1. The longitudinal section of the second transition section II-1 can be an isosceles trapezoid, and the outward inclination angle α of the side of the isosceles trapezoid can be 5-85°, preferably 15-75°.

[0077] In the catalytic cracking reactor of this application, the large bottom space of the narrowed reaction section, especially the conical reaction section, can effectively increase the catalyst density in the reactor, thereby significantly increasing the ratio of catalyst to reactants in the reactor, enhancing the primary cracking reaction of the reactants, improving not only the reaction conversion rate but also the yield of low-carbon olefins. Moreover, the narrowed structure of the narrowed reaction section, especially the conical reaction section, facilitates the acceleration of the reaction oil and gas leaving the reaction zone, shortens the reaction time, and reduces catalyst backmixing, which helps to reduce the secondary conversion reaction of low-carbon olefins generated in the primary reaction and improves the selectivity of low-carbon olefins.

[0078] In other embodiments, the reaction zone includes one or more narrow-diameter reaction sections, each of which independently comprises two or more hollow cylinders with decreasing inner diameters. In this case, the reaction zone is a cylindrical shape comprising two or more hollow cylindrical sections. The cross-sectional inner diameter of each of the two or more hollow cylindrical sections is independently 0.2-5 meters, preferably 0.4-3 meters, and the ratio of this inner diameter to the total height of the reactor is 0.01:1 to 0.5:1, preferably 0.05:1 to 0.2. The ratio of the height of each of the two or more hollow cylindrical sections to the total height of the reactor is independently 0.15:1 to 0.8:1, preferably 0.2:1 to 0.75:1, and the ratio of the height of the reaction zone to the total height of the reactor is 0.15:1 to 0.8:1, preferably 0.2:1 to 0.75:1.

[0079] In the catalytic cracking reactor provided in this application, the reactor may be provided with one or more, for example, one, two or more, feed inlets 9, 16. These feed inlets 9, 16 may be independently located at the outlet end of the pre-lifting zone I or at the bottom of the reaction zone II. More preferably, the multiple feed inlets are each independently located at the same height or different heights within the reaction zone II. Figure 2 As shown, one raw material inlet 9 can be located at the outlet end of the pre-lifting zone I, and another raw material inlet 16 can be located at the outlet end of the first diameter-reducing reaction section 100 of the reaction zone II. Therefore, raw materials of different properties can be fed through different raw material inlets. For example, C4-C12 hydrocarbon raw materials can be fed through raw material inlet 9, and C12-C20 hydrocarbon raw materials can be fed through raw material inlet 16.

[0080] like Figure 1 and Figure 2 As shown, the catalytic cracking reactor may include an outlet zone III. In one embodiment, the outlet zone III may be a hollow cylindrical shape, with its cross-sectional inner diameter and height h. III The ratio is 0.01-0.3:1, and the height h of the exit area is... IIIThe ratio of the height 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 previously stated, 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 can be connected by a third transition section (not shown). The longitudinal section of this third transition section can be an isosceles trapezoid, and the outward inclination angle α of the side of the isosceles trapezoid can be 5-85°, preferably 15-75°.

[0083] The outlet end of the outlet zone III can be open or directly connected to the inlet of the cyclone separator.

[0084] This application also provides a catalytic cracking system, which includes a catalytic cracking reactor, an oil separation unit, a stripping unit, an optional reaction product separation unit, and a regenerator, wherein the catalytic cracking reactor includes one or more of the catalytic cracking reactors described above in this application.

[0085] Figure 3 and Figure 4 A catalytic cracking system incorporating the aforementioned catalytic cracking reactor of this application is shown. Wherein, Figure 3 Catalytic cracking reactors in such reactors Figure 1 As shown, Figure 4 Catalytic cracking reactors in such reactors Figure 2 As shown.

[0086] like Figure 3 and Figure 4 As shown, the catalytic cracking system includes the catalytic cracking reactor 1, oil-to-chemicals separation device 5, settling tank 3, stripping device 4, and regenerator 2 described in this application.

[0087] The catalytic cracking reactor 1 is provided with a catalyst inlet 13 at the bottom, a raw material inlet 9, 16 at the bottom and an oil outlet 150 at the top;

[0088] The oil-catalyst separation unit 5 is used to separate the reaction products and catalyst from the oil in the catalytic cracking reactor 1;

[0089] Settler 3 is used to settle the catalyst separated by oil separator 5 before it enters stripping unit 4;

[0090] Stripping unit 4 is used to strip the catalyst therein in order to recover the reaction oil and gas;

[0091] The regenerator 2 is connected to the stripping unit 4 via the regeneration inclined tube 12, which is used to allow the regenerated catalyst from the stripping unit 4 to enter the regenerator 2 for regeneration; the regenerator 2 is also connected to the catalytic cracking reactor 1 via the regeneration inclined tube 13, which is used to allow the regenerated catalyst regenerated by the regenerator 2 to be recycled back to the catalytic cracking reactor 1 for reaction.

[0092] In the catalytic cracking system of this application, there can be one or more catalytic cracking reactors. These reactors can be a combination of one catalytic cracking reactor from this application with other existing catalytic cracking reactors, or a combination of multiple catalytic cracking reactors from this application. These reactors can be connected in parallel and connected to an oil-solvent separation unit.

[0093] The reaction oil and gas (i.e., reaction products) separated by the oil-reaction separator 5 are collected in the gas collecting chamber 6 and then transported via pipeline 7 to a subsequent reaction product separation device (not shown) for further separation. This reaction product separation device may be equipped with a reaction product inlet, a dry gas outlet, a liquefied petroleum gas (LPG) outlet, a cracked gasoline outlet, a cracked diesel outlet, and a cracked heavy oil outlet, used to separate the reaction products into dry gas, LPG, cracked gasoline, cracked diesel, and cracked heavy oil according to their distillation range.

[0094] In regenerator 2, the catalyst to be generated is burned under the action of oxygen-containing regeneration gas introduced through pipeline 14 to obtain regenerated catalyst, which is then fed into reactor 1 through regeneration inclined pipe 13; while flue gas is discharged through pipeline 15 into the energy recovery system.

[0095] In the catalytic cracking system of this application, at least one fuel oil inlet can be provided in the lower part of the stripping unit 4 and / or in the connecting pipeline 12 between the stripping unit and the regenerator to provide additional fuel oil to the catalyst to be recycled. This allows the fuel oil to form additional coke on the catalyst before it enters the regenerator. After entering the regenerator, the fuel oil is uniformly distributed in the catalyst bed, and under the action of oxygen-containing gas, it can burn stably and uniformly, releasing heat. This achieves synergistic control of fuel oil distribution and coking on the catalyst, avoiding localized hot spots and effectively protecting the catalyst's performance.

[0096] In one embodiment, at least one fuel oil inlet 11 is provided at the lower part of the stripping device, wherein the fuel oil inlet 11 is located at a distance L from the bottom end of the stripping device. 11 Each of these values ​​is independently 0-30% of the height h4 of the stripping device, preferably 5%-25%.

[0097] In the catalytic cracking system provided in this application, the stripping unit, oil-to-reagent separation unit, regenerator, other units, and reaction product separation unit can all be equipment well known to those skilled in the art, and the connection methods between these units can also be carried out in accordance with methods known in the art. For example, the oil-to-reagent separation unit may include a cyclone separator and an outlet rapid separator. In some specific embodiments, the oil-to-reagent separation unit includes a settling device arranged coaxially or at different heights with the catalytic cracking reactor.

[0098] On the other hand, this application provides a catalytic cracking method, which includes the step of bringing reactants and catalysts into contact and reacting in the catalytic cracking system described above in this application.

[0099] The catalytic cracking reactor and system provided in this application are suitable for catalytic cracking reactions of various feedstocks, such as light hydrocarbons or light distillate oils, oxygenated hydrocarbons, shale oils, hydrorefined wax oils, hydrotreated wax oils, hydrocracking tail oils, or a mixture of one or more of the above feedstocks to produce low-carbon olefins, especially the reaction of catalytic cracking of light hydrocarbons or light distillate oils to produce low-carbon olefins.

[0100] For example, the light hydrocarbon or light distillate oil can be a gaseous hydrocarbon, petroleum hydrocarbon with a distillation range of 25–350°C, oxygenated compounds, or distillate oil derived from biomass or waste plastics; the gaseous hydrocarbon can be selected from one or more mixtures of saturated liquefied petroleum gas (LPG), unsaturated LPG, and C4 fractions; the petroleum hydrocarbon can be selected from one or more mixtures of primary processed straight-run naphtha, straight-run kerosene, and straight-run diesel; and secondary processed topping oil, residue oil, hydrocracked light naphtha, pentane oil, coking gasoline, Fischer-Tropsch synthetic oil, catalytic cracked light gasoline, hydrotreated gasoline, and hydrotreated diesel. In one embodiment, the reaction feedstock is selected from C4-C20 light feedstock oils.

[0101] In one embodiment, the reaction conditions in the reaction zone include: a reaction temperature of 510-750°C, a reaction time of 0.5-10 seconds, an agent-to-oil weight ratio of 10:1 to 50:1, and a water-to-oil weight ratio of 0.05:1 to 2.0:1.

[0102] In one embodiment, the reaction conditions in the reaction zone include: a reaction temperature of 550-700°C, a reaction time of 1-5 seconds, an agent-to-oil weight ratio of 20:1 to 40:1, and a water-to-oil weight ratio of 0.2:1 to 0.8:1.

[0103] In one embodiment, the catalyst comprises, on a dry basis and based on the dry weight of the catalyst, 1-50 wt%, preferably 5-45 wt%, more preferably 10-40 wt% of zeolite; 5-99 wt%, preferably 10-80 wt%, more preferably 20-70 wt% of inorganic oxide; and 0-70 wt%, preferably 5-60 wt%, more preferably 10-50 wt% of clay.

[0104] In one embodiment, the zeolite includes mesoporous zeolite and optionally macroporous zeolite, wherein the mesoporous zeolite is selected from ZSM series zeolite, ZRP zeolite, and any combination thereof; and the macroporous zeolite is selected from rare earth Y-type zeolite, rare earth hydrogen Y-type zeolite, ultrastable Y-type zeolite, and high silica Y-type zeolite, and any combination thereof.

[0105] In one embodiment, the mesoporous zeolite accounts for 10-100% by weight, preferably 50-90% by weight, on a dry basis, of the total weight of the zeolite.

[0106] In this application, the terms mesoporous zeolite and macroporous zeolite are defined according to conventional definitions in the art, namely, the average pore size of mesoporous zeolite is about 0.5-0.6 nm, and the average pore size of macroporous zeolite is about 0.7-1.0 nm.

[0107] As an example, the macroporous zeolite may 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-silica Y type zeolite. The mesoporous zeolite may be selected from zeolites with an MFI structure, such as ZSM series zeolites and / or ZRP zeolite. Optionally, the above-mentioned mesoporous zeolites may 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 US Patent 5,232,675A. The ZSM series zeolites are preferably selected from one or more mixtures of ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38, ZSM-48, and other zeolites with similar structures. A more detailed description of ZSM-5 can be found in US Patent 3,702,886A.

[0108] According to this application, the inorganic oxide, as a binder, is preferably silicon dioxide (SiO2) and / or aluminum oxide (Al2O3). The clay, as a matrix (i.e., carrier), is preferably kaolin and / or hydrous kaolin.

[0109] In one embodiment, a reaction directing agent is introduced into the catalytic cracking reactor through a reaction directing agent inlet. The reaction directing agent is selected from water and petroleum distillate oil, and the petroleum distillate oil is selected from one or more of gasoline distillate, diesel distillate, wax oil distillate, and slurry oil.

[0110] In one embodiment, the feed weight ratio of the reaction directing agent to the reaction raw material is 0.03-0.3:1.

[0111] In one embodiment, at least one fuel oil inlet is provided in the lower part of the stripping unit of the catalytic cracking system and / or in the connecting pipeline between the stripping unit and the regenerator.

[0112] The method includes: injecting fuel oil through the fuel oil inlet, so that the stripped catalyst and fuel oil enter the regenerator for regeneration.

[0113] The fuel oil injection rate to the feed weight ratio of the reaction raw materials is 0.05-0.2:1. In one embodiment, the temperature of the regenerated catalyst after regeneration in the regenerator is 680-780°C.

[0114] The catalytic cracking reactor, system, and method of this application can efficiently produce chemical feedstocks such as ethylene and propylene from light petroleum hydrocarbons, helping refineries to transform, develop, and extend from oil refining to chemical feedstock production. This not only solves the problem of petrochemical feedstock shortage but also improves the economic efficiency of refineries.

[0115] The present application will be further described below with reference to the preferred embodiments shown in the accompanying drawings, but this does not limit the present application.

[0116] Figure 1 A preferred embodiment of the catalytic cracking reactor of this application is provided, wherein the catalytic cracking reactor 1 comprises, from bottom to top, a pre-lifting zone I, a reaction zone II, and an outlet zone III. The reaction zone II includes a narrowed reaction section 100, which is a hollow truncated cone with an isosceles trapezoidal longitudinal section. A catalyst inlet 110 is provided at the lower part of the pre-lifting zone I, and a raw material inlet 9 is provided at the upper part of the pre-lifting zone I and / or the bottom of the reaction zone II. The inner diameter of the cross-section at the bottom of the reaction zone II is larger than the inner diameter of the pre-lifting zone I, and the inner diameter of the cross-section at the top is equal to the inner diameter of the pre-lifting zone I and the inner diameter of the outlet zone III. One or more, for example, one, two, or more reaction directing agent inlets 10 are provided on the downstream sidewall of the reaction zone II.

[0117] Figure 3 Showing contains Figure 1 The catalytic cracking system of the catalytic cracking reactor 1, wherein the lower sidewall of the stripper 4 is provided with one or more, for example one, two or more supplementary fuel oil inlets 11.

[0118] The pre-lifting medium enters the catalytic cracking reactor 1 from the bottom of the pre-lifting zone I via pipeline 8. The pre-lifting medium can be dry gas, steam, or a mixture thereof. Hot regenerated catalyst from the regeneration inclined tube 13 enters the lower part of the pre-lifting zone I and moves upward under the lifting action of the pre-lifting medium. Reactant feedstocks, such as preheated light feed oil and atomized steam, are injected upstream of the pre-lifting zone I and / or at the bottom of the reaction zone II via feed pipeline 9, mixing and contacting with the existing catalyst in the catalytic cracking reactor, and undergoing catalytic cracking reaction as they pass through the reaction zone II from bottom to top. The reaction products flow upwards and come into contact with the reaction directing agent injected through the reaction directing agent inlet 10, causing the reaction to terminate in time. The resulting catalyst with coke and the reaction oil and gas enter the oil-solid separation device 5, such as a cyclone separator, through outlet zone III for gas-solid separation. The separated reaction oil and gas are led out through the gas collection chamber 6 and the large oil and gas pipe 7 and enter the subsequent separation system. The separated catalyst with coke enters the stripper. The stripped catalyst comes into contact with the fuel oil injected through the supplementary fuel oil inlet 11 and further deposits coke. Then, it enters the regenerator 2 through the regenerator inclined pipe 12 and mixes with the air 14 at the bottom of the regenerator for coke burning and regeneration. The regenerated catalyst is returned to the reactor 1 for recycling through the regeneration inclined pipe 13. The regenerated flue gas enters the energy recovery system through pipeline 15.

[0119] Figure 2 Another preferred embodiment of the catalytic cracking reactor of this application is provided, wherein the reactor comprises, from bottom to top, a pre-lifting zone I, a reaction zone II, and an outlet zone III. The reaction zone II includes two narrow-diameter reaction sections 100 and 100', both cylindrical in shape comprising two hollow truncated conical sections, each with an isosceles trapezoidal longitudinal section. A catalyst inlet is located at the lower part of the pre-lifting zone I, a raw material inlet is located upstream of the pre-lifting zone I and / or at the bottom of the first reaction section 100, and a raw material or reclaimed material inlet is located at the bottom of the second reaction section 100'. The inner diameter of the cross-section at the bottom end of each hollow truncated conical section is larger than the inner diameter of the pre-lifting zone I, and the inner diameter of the cross-section at the top end is equal to the inner diameter of the pre-lifting zone I and the inner diameter of the outlet zone II. One or more, for example, one, two, or more reaction directing agent inlets 10 are located on the downstream sidewall of the second reaction section.

[0120] Figure 4 Showing contains Figure 2 The catalytic cracking system of the catalytic cracking reactor 1, wherein the lower sidewall of the stripper is provided with one or more, for example one, two or more supplementary fuel oil inlets 11.

[0121] The pre-lifting medium enters the catalytic cracking reactor from the bottom of the pre-lifting zone I via pipeline 8. The pre-lifting medium can be dry gas, steam, or a mixture thereof. The hot regenerated catalyst, whether cooled or uncooled, from the regeneration inclined tube 13 enters the lower part of the pre-lifting zone I and moves upward under the lifting action of the pre-lifting medium. Reactants, such as preheated light feedstock oil and atomized steam, are injected into the upper reaches of the pre-lifting zone I and / or the bottom of the first reaction section 100 via feed pipeline 9, where they mix and react with the existing catalyst in the catalytic cracking reactor. The reaction stream mixes with recycled C4 introduced from the bottom of the second reaction section 100' via pipeline 16 for further reaction. The reaction products flow upward and contact with the reaction directing agent injected via pipeline 10 to quench the cracking reaction in a timely manner. The catalyst containing coke and the reaction oil and gas enter the oil-agent separator 5, such as a cyclone separator, via outlet zone III. The gas-solid separation process is carried out in the separator. The separated reaction oil and gas are led out through the gas collection chamber 6 and the large oil and gas pipe 7 and enter the subsequent separation system. The catalyst with coke is separated and enters the stripper. The stripped catalyst comes into contact with the fuel oil injected through the supplementary fuel oil inlet 11. After further coke deposition, it enters the regenerator 2 through the regenerator inclined pipe 12 and mixes with the air 14 at the bottom of the regenerator for coke burning and regeneration. The regenerated catalyst is returned to the reactor 1 for recycling through the regeneration inclined pipe 13. The regenerated flue gas enters the energy recovery system through the pipeline 15.

[0122] Example

[0123] The following embodiments will further illustrate this application, but do not limit this application.

[0124] The feedstock used in the following examples and comparative examples is straight-run naphtha, the properties of which are shown in Table 1. The catalyst used is a commercial catalytic cracking catalyst purchased from the Catalyst Division of China Petroleum & Chemical Corporation, with the brand name NCC.

[0125] Example 1

[0126] Using the feedstock and NCC catalyst shown in Table 1, in Figure 1 The experiment was conducted on the medium-sized apparatus shown, in which the reactor structure is as follows:

[0127] The reactor has a total height of 10 meters, including a 2-meter pre-lifting zone with an inner diameter of 0.2 meters; a 5-meter reaction zone with an inner diameter of 0.2 meters at the top and 0.3 meters at the bottom; and a 3-meter outlet zone with an inner diameter of 0.2 meters. The inlet of the reaction directing agent is located 0.5 meters from the outlet.

[0128] In the stripper, the replenishment fuel oil inlet is located at a distance of 10% of the height of the stripping device from the bottom end of the stripping unit.

[0129] The hot-regenerated catalyst from the regeneration inclined tube 13 enters the lower part of the pre-lifting zone I and moves upward under the lifting action of the pre-lifting medium. Preheated feed oil and atomized steam are injected into the upper part of the pre-lifting zone I through the feed line 9, where they mix and contact with the existing catalyst in the catalytic cracking reactor, and carry out the catalytic cracking reaction as they pass through the reaction zone II from bottom to top. The reaction products flow upwards and come into contact with the reaction directing agent injected through the reaction directing agent inlet 10, causing the reaction to terminate in time. The resulting catalyst with coke and the reaction oil and gas enter the oil-solid separation device 5, such as a cyclone separator, through outlet zone III for gas-solid separation. The separated reaction oil and gas are led out through the gas collection chamber 6 and the large oil and gas pipe 7 and enter the subsequent separation system. The separated catalyst with coke enters the stripper. The stripped catalyst comes into contact with the fuel oil injected through the supplementary fuel oil inlet 11 and further deposits coke. Then, it enters the regenerator 2 through the regenerator inclined pipe 12 and mixes with the air 14 at the bottom of the regenerator for coke burning and regeneration. The regenerated catalyst is returned to the reactor 1 for recycling through the regeneration inclined pipe 13. The regenerated flue gas enters the energy recovery system through pipeline 15.

[0130] During operation, the ratio of reaction directing agent injection to feedstock is 0.05:1 (by weight), and the fuel oil injection is 6% of the feedstock.

[0131] The operating conditions and product distribution are listed in Table 2. As can be seen from Table 2, the ethylene yield in this embodiment reached 25.53% by weight, the propylene yield reached 24.21% by weight, and the methane and coke yields were 10.07% by weight and 3.70% by weight, respectively.

[0132] Example 2

[0133] The feedstock and NCC catalyst shown in Table 1 were used in a medium-sized plant test. Figure 2 The configuration shown includes a reaction zone comprising two consecutive hollow truncated conical segments, wherein...

[0134] The structure of the reactor used is as follows:

[0135] The reactor has a total height of 10 meters. The pre-lifting zone is 2 meters high with an inner diameter of 0.2 meters; the reaction zone is 5 meters high, with the first hollow truncated cone section having a height h1 of 2.5 meters, an inner diameter of 0.2 meters at the top cross-section, and an inner diameter of 0.3 meters at the bottom cross-section; the second hollow truncated cone section has a height h1 of 2.45 meters, an inner diameter of 0.2 meters at the top cross-section, and an inner diameter of 0.3 meters at the bottom cross-section; and the outlet zone has a height of 3 meters and an inner diameter of 0.2 meters. The reaction directing agent inlet is located 0.2 meters from the outlet end of the second hollow truncated cone.

[0136] In the stripper, the replenishment fuel oil inlet is located at a distance of 10% of the height of the stripping device from the bottom end of the stripping unit.

[0137] The hot regenerated catalyst, whether cooled or not, from the regeneration inclined tube 13 enters the lower part of the pre-lifting zone I and moves upward under the lifting action of the pre-lifting medium. Preheated feedstock oil enters the upper part of the pre-lifting zone through feed inlet 9, contacts the catalytic cracking catalyst, and enters two reaction sections from bottom to top for catalytic cracking reaction. At the bottom of the second reaction section 100', it is introduced into the refining C4 via pipeline 16 for further reaction. The reaction products flow upward and contact the reaction directing agent injected via pipeline 10 to quench the cracking reaction in time. The catalyst with coke and the reaction oil and gas enter the oil-solid separation device 5, such as a cyclone separator, through outlet zone III for gas-solid separation. The separated reaction oil and gas are led out through the gas collection chamber 6 and the large oil and gas pipe 7 to enter the subsequent separation system. The separated catalyst with coke enters the stripper. The stripped catalyst contacts the fuel oil injected through the supplementary fuel oil inlet 11, and after further coke deposition, it enters the regenerator 2 through the regenerator inclined pipe 12 to mix with the air 14 at the bottom of the regenerator for coke burning and regeneration. The regenerated catalyst is returned to the reactor 1 for recycling through the regeneration inclined pipe 13. The regenerated flue gas enters the energy recovery system through pipeline 15.

[0138] During operation, the ratio of reaction directing agent injection to feedstock is 0.05:1 (by weight), and the fuel oil injection is 6% of the feedstock.

[0139] The operating conditions and product distribution are listed in Table 2. As can be seen from Table 2, the ethylene yield in this embodiment reached 26.53% by weight, the propylene yield reached 26.13% by weight, and the methane and coke yields were 10.77% by weight and 3.86% by weight, respectively.

[0140] Comparative Example 1

[0141] Using the feedstock and NCC catalyst shown in Table 1, experiments were conducted on a medium-sized unit using a conventional riser reactor. Preheated feedstock entered the lower part of the riser reaction zone and contacted the catalytic cracking catalyst for catalytic cracking. The post-reaction stream entered subsequent oil-catalyst separation units and product separation equipment. Operating conditions and product distribution are listed in Table 2.

[0142] As can be seen from the results in Table 2, the ethylene yield in this comparative example is only 18.19% by weight, the propylene yield is only 20.14% by weight, and the methane and coke yields are 12.95% by weight and 3.92% by weight, respectively.

[0143] As can be seen from the results of the above examples and comparative examples, when naphtha catalytic cracking reactor and system of this application are used for naphtha catalytic cracking reaction, the yields of ethylene and propylene are significantly increased, while the yields of methane and coke are reduced.

[0144] The preferred embodiments of this application have been described in detail above. However, this application is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this application, various simple modifications can be made to the technical solution of this application, and these simple modifications all fall within the protection scope of this application.

[0145] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this application will not describe the various possible combinations separately.

[0146] Furthermore, various different embodiments of this application can be combined in any way, as long as they do not violate the spirit of this application, they should also be regarded as the content of this application.

[0147] Table 1 Properties of the straight-run naphtha used

[0148] Density (20°C) / (grams per centimeter 3 ) 0.7525 Carbon content / weight % 87.47 Hydrogen content / weight % 14.53 Sulfur content (mg / L) 140 Nitrogen content (mg / L) 1.2 Distillation range / ℃ 10% by volume 90.9 30% by volume 121.7 50% by volume 145.8 70% by volume 167.3 95% by volume 197.5 Hydrocarbon composition / weight % Alkanes 58.30 Olefins 0 Cycloalkanes 30.18 Aromatics 11.52

[0149] Table 2 Comparison of reaction results between Examples 1-2 and Comparative Example 1

[0150] Example 1 Example 2 Comparative Example 1 Reaction zone conditions Reaction zone outlet temperature, °C 675 675 675 Reaction time, seconds 2.0 2.1 2.5 Water-oil weight ratio 0.3 0.3 0.3 Oil weight ratio 30 30 30 Recycled C4 as a percentage of raw materials by weight / % 10 Product distribution, weight % H2~C2 40.31 42.32 39.44 Methane 10.07 10.77 12.95 ethylene 25.53 26.53 18.19 C3~C4 38.15 34.79 36.49 Among them, propylene 24.21 26.13 20.14 gasoline 15.55 16.73 17.23. fuel oil 2.29 2.30 2.92 coke 3.70 3.86 3.92 total 100 100 100

Claims

1. A catalytic cracking system, the catalytic cracking system comprising a catalytic cracking reactor, an oil separation unit, a stripping unit, an optional reaction product separation unit, and a regenerator, wherein the regenerator is connected to the stripping unit via a regenerating inclined tube, characterized in that, The catalytic cracking reactor includes one or more catalytic cracking reactors, which, from bottom to top, comprise: Pre-upgrade area The reaction zone includes at least one diameter-reducing reaction section, which is a hollow cylinder with a generally circular cross-section and open at the bottom and top, its inner diameter decreasing continuously or discontinuously from bottom to top; and The outlet zone has a cross-sectional inner diameter to height ratio of 0.01-0.3:1, and the height of the outlet zone is in the ratio of 0.05:1 to 0.5:1 to the total height of the reactor. The pre-lifting zone is connected to the bottom of the reaction zone, and the top of the reaction zone is connected to the outlet zone; at least one raw material inlet is provided at the outlet end of the pre-lifting zone, and a catalyst inlet is provided at the bottom of the pre-lifting zone. The inner diameter of the cross-section at the bottom of the reaction zone is greater than the inner diameter of the cross-section of the pre-lifting zone, and the inner diameter of the cross-section at the top is equal to or less than the inner diameter of the cross-section of the pre-lifting zone and the inner diameter of the cross-section of the outlet zone. The pre-lifting zone and the reaction zone are connected by a first connecting section, the longitudinal section of which is an isosceles trapezoid with an outward inclination angle α of 5-85 degrees on the side of the isosceles trapezoid. o ; One or more reaction directing agent inlets are provided downstream of the reaction zone, and the distance between the one or more reaction directing agent inlets and the outlet end of the reaction zone is 0% to 20% of the total height of the reaction zone. At least one supplementary fuel oil inlet is provided in the lower part of the stripping unit and / or in the connecting pipeline between the stripping unit and the regenerator. The oil-separation device is used to separate the catalyst containing coke from the reaction oil and gas. The separated catalyst containing coke enters the stripping device. The stripped catalyst comes into contact with the fuel oil injected through the supplementary fuel oil inlet. After further coke deposition, it enters the regenerator for regeneration through the prepared inclined tube.

2. The catalytic cracking system according to claim 1, characterized in that, At least one supplementary fuel oil inlet is provided at the bottom of the stripping unit. The distance between each of the at least one supplementary fuel oil inlet and the bottom of the stripping unit is independently 0-30% of the height of the stripping unit.

3. The catalytic cracking system according to claim 1 or 2, wherein the oil separation device includes a settling device arranged coaxially or parallel to the catalytic cracking reactor at different heights.

4. The catalytic cracking system according to claim 1 or 2, wherein the ratio of the bottom cross-sectional inner diameter of the reaction zone to the total height of the reactor is 0.01:1 to 0.5:1; and the ratio of the total height of the reaction zone to the total height of the reactor is 0.15:1 to 0.8:

1.

5. The catalytic cracking system according to claim 1 or 2, characterized in that, The reaction zone includes 1-3 diameter-reducing reaction sections.

6. The catalytic cracking system according to claim 5, characterized in that, The reduced-diameter reaction section is in the form of a hollow truncated cone, with an isosceles trapezoidal longitudinal section. 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 reactor is independently 0.15:1 to 0.8:

1.

7. The catalytic cracking system according to claim 6, characterized in that, The inner diameter of the top cross-section of each of the reduced-diameter reaction sections is independently 0.2-5 meters.

8. The catalytic cracking system according to claim 1 or 2, characterized in that, The ratio of the inner diameter to the height of the pre-lifting zone 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.

9. The catalytic cracking system according to claim 8, characterized in that, The inner diameter of the pre-lifting zone is 0.2-5 meters.

10. The catalytic cracking system according to claim 1 or 2, characterized in that, The cross-sectional inner diameter of the outlet area is 0.2-5 meters.

11. A catalytic cracking method, comprising the step of contacting reactants and catalyst in a catalytic cracking system according to any one of claims 1 to 10.

12. The catalytic cracking method according to claim 11, wherein, The reaction feedstock is selected from light feedstock oils of C4-C20.

13. The catalytic cracking method according to claim 12, wherein, A reaction directing agent is introduced into the catalytic cracking reactor through the reaction directing agent inlet. The reaction directing agent is selected from water and petroleum distillate oil, and the petroleum distillate oil is selected from one or more of gasoline distillate, diesel distillate, wax oil distillate and slurry oil.

14. The catalytic cracking method according to claim 13, wherein, The feed weight ratio of the reaction directing agent to the reaction raw material is 0.03-0.3:

1.

15. The catalytic cracking method according to claim 12, wherein, The temperature of the regenerated catalyst after regeneration in the regenerator is 680-780℃.

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