A light raw material catalytic cracking reaction method and system

Abstract

This application relates to a method and system for catalytic cracking of light feedstocks. The system comprises a catalytic cracking reactor, a coke generator, an oil-agent separation device, a settler, and a regenerator. Using this system for catalytic cracking of light feedstocks can improve ethylene and propylene selectivity, address reaction heat balance issues, and maintain the physical and chemical properties of the catalyst.

Description

Technical Field

[0001] The present application relates to the field of fluidized catalytic cracking technology, and more specifically, to a reaction method and system suitable for catalytic cracking of light raw materials. Background Art

[0002] Currently, refining companies face overcapacity, slowing terminal consumption of refined oil products, and a structural oversupply of refined oil products, a pressing issue for them. In the chemical raw material market, demand for ethylene and propylene, essential chemical raw materials, remains strong. Therefore, the transition from refining to chemical processing has become an inevitable trend in refinery development. Catalytic cracking, as the link between refining and chemical processing, is a key technology in this transition.

[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. To address this issue, existing technologies have addressed the regenerator system. For example, they employ methods such as creating an oxygen-depleted zone within the regenerator, introducing fuel oil into the oxygen-depleted zone to mix with the catalyst before entering the regenerator for charring and regeneration. Alternatively, heaters are placed within the regenerator, employing fuel nozzles that inject a mixture of fuel and oxygen-containing gas for combustion and heat supplementation. Alternatively, methane is injected, relying on the heat released by methane combustion to supplement the reaction. While these heat supplementation methods mitigate some of the adverse effects on the catalyst, they do not fundamentally address the impact of high-temperature hotspots generated by the localized combustion of external fuel oil on the catalyst's skeletal structure and reaction performance, which can severely impact reaction selectivity.

[0005] Therefore, when developing catalytic cracking technology for light raw materials to improve the selectivity of low-carbon olefins, insufficient heat balance is also a technical problem that must be solved. Summary of the Invention

[0006] The purpose of this application is to provide a method and system for catalytic cracking of light raw materials, which can improve the yield of ethylene and propylene and solve the problem of heat balance in the reaction process from the reaction aspect without damaging the performance of the catalyst.

[0007] In one aspect, the present application provides a catalytic cracking reaction-regeneration system, comprising:

[0008] Catalytic cracking reactor,

[0009] coke generator,

[0010] Oil separation equipment,

[0011] settler, and

[0012] Regenerator,

[0013] The catalytic cracking reactor is provided with a lifting medium inlet, a regenerated catalyst inlet, a cracking feedstock oil inlet and an oil agent outlet;

[0014] The catalytic cracking reactor is coaxially arranged with the settler, and the oil separation device is accommodated inside the settler. The oil outlet of the catalytic cracking reactor is connected to the oil separation device, so that the oil in the catalytic cracking reactor enters the oil separation device and is separated into a first reaction product and a first spent catalyst.

[0015] The coke generator includes, from bottom to top,

[0016] Pre-lift area,

[0017] a coke-forming reaction zone, wherein the coke-forming reaction zone is a bubbling fluidized bed or a turbulent fluidized bed, and

[0018] Export Zone,

[0019] wherein the top of the pre-lifting zone is connected to the coke-generating reaction zone, and the top of the coke-generating reaction zone is connected to the outlet zone;

[0020] At least one fuel oil feed port is provided in the middle and upstream of the coking reaction zone;

[0021] The coke generator is arranged outside the settler, and the outlet area of the coke generator is connected to the oil-agent separation device, so that the material of the coke generator enters the oil-agent separation device and is separated into the second reaction product and the second catalyst to be generated;

[0022] The regenerator is provided with a first regenerated catalyst outlet and a second regenerated catalyst outlet, wherein the first regenerated catalyst outlet is connected to the regenerated 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;

[0023] The lower part of the settler is provided with a stripping section, and the stripping section of the settler is provided with a first catalyst outlet and a second catalyst outlet; the first catalyst outlet of the settler is communicated with the regenerator, so that at least a portion of the settler catalyst in the settler is transported to the regenerator; the bottom end of the pre-lifting zone of the coking reaction zone and / or the bottom end of the coking reaction zone of the coking reaction zone is configured to be communicated with the second catalyst outlet of the settler, and the second regenerated catalyst outlet of the regenerator is connected to the pipeline connecting the settler and the coking reaction zone, so that at least a portion of the regenerated catalyst of the regenerator can be mixed with at least a portion of the settler catalyst of the settler and then transported to the coking reaction zone.

[0024] In one embodiment, the coke generator is provided with the pre-lift gas inlet, the catalyst inlet and the fuel oil inlet in sequence from bottom to top.

[0025] In one embodiment, the fuel oil inlets are independently disposed in the middle and upstream of the coke maker; preferably, the distance between the fuel oil inlets and the bottom of the coke maker is independently 5% to 15% of the height of the coke maker.

[0026] In one embodiment, the coke-generating reaction zone is a hollow cylinder with an aspect ratio of 20:1 to 2:1.

[0027] In one embodiment, the pre-lifting area is a hollow cylinder with an aspect ratio of 10:1 to 2:1;

[0028] The outlet area is a hollow cylinder with a length-to-diameter ratio of 30:1-5:1.

[0029] In one embodiment, the ratio of the inner diameters of the pre-elevation zone, the coking reaction zone, and the outlet zone is 1:2:1 to 1:10:2.

[0030] In one embodiment, the catalytic cracking reaction is selected from one of a riser and a downer or a combination thereof, and the ratio of the inner diameter of the catalytic cracking reactor to the coking reaction zone is 0.1-0.5:1.

[0031] In one aspect, the present application provides a method for catalytic cracking of a light feedstock, which is performed in a catalytic cracking reaction-regeneration system of the present application, and comprises:

[0032] 1) introducing preheated light crude oil from the lower part of the cracking reactor, contacting with the regenerated catalyst from the regenerator and performing catalytic cracking reaction from bottom to top to obtain a first reaction product and a first catalyst to be regenerated,

[0033] 2) introducing the coke raw material from the lower part of the coke generator, contacting it with the settler catalyst from the settler and / or the regenerated catalyst from the regenerator and performing a coke forming reaction to obtain a second reaction product and a second catalyst to be regenerated;

[0034] 3) introducing the first reaction product and the second reaction product into a separation system for separation,

[0035] 4) The settler catalyst from the settler is transported to the regenerator for char regeneration, and the obtained regenerated catalyst is recycled.

[0036] In one embodiment, the light feedstock is selected from gaseous hydrocarbons with a carbon number of C4-C20 and light distillate oil.

[0037] 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.

[0038] 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;

[0039] Preferably, the C4 hydrocarbons or C5-C6 light gasoline fraction is introduced downstream of the feed point where the light feedstock is introduced into the cracking reactor.

[0040] In one embodiment, the conditions of the coking reaction include: a reaction temperature of 460-560°C, a reaction time of 1-20 seconds, a catalyst-oil weight ratio of 3:1 to 30:1, a weight ratio of pre-lifting gas to coking raw material of 0.01:1 to 0.05:1, a linear velocity of 0.2-0.8 m / s, and a catalyst particle density of 300-700 kg / m3.

[0041] In one embodiment, the coke raw material is the device's self-produced cracking heavy oil 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, catalytic cracking slurry, catalytic cracking slurry, coker gasoline, coker diesel and coker gas oil; more preferably, the coke raw material is the device's self-produced cracking heavy oil.

[0042] The catalytic cracking reaction-regeneration system of the present application includes a cracking reactor and a coking device. The reaction oil and gas generated by the cracking reactor and the reaction oil and gas generated by the coking device can enter the oil agent separation equipment together, which helps to reduce the temperature of the mixed oil and gas and reduce over-cracking reaction. The coke generated by the coking reactor in the catalytic cracking reaction system enters the regeneration system together with the coke generated by the cracking reactor for regeneration, which does not affect the operation of the regeneration system. There are no local hot spots in the carbonized catalyst during the coking process in the regenerator, and there is no damage to the physical and chemical properties of the catalyst. The reaction system of the present application has a simple structure, is easy to implement, and has strong applicability. In particular, the catalytic cracking device with chemical raw materials such as low-carbon olefins as the main target products fundamentally solves the problem of thermal balance of the catalytic cracking reaction from the reaction system end, and reduces the damage to the catalyst and the regeneration system caused by the traditional method of spraying combustion oil, which not only saves the cost of the catalyst, but also improves the economic benefits of the refinery. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] 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:

[0044] Figure 1 This is a schematic diagram of the coke generator for this application;

[0045] Figure 2 A schematic diagram of a catalytic cracking system according to an embodiment of the present application. DETAILED DESCRIPTION

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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, the endpoints and the specific points in the range, and the specific points between the endpoints can be used to form one or more new numerical ranges, and these new numerical ranges should also be considered to be specifically disclosed herein.

[0051] 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.

[0052] 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.

[0053] The present application provides a catalytic cracking reaction-regeneration system, which comprises:

[0054] Catalytic cracking reactor,

[0055] coke generator,

[0056] Oil separation equipment,

[0057] settler, and

[0058] Regenerator.

[0059] The present application also provides a method for catalytic cracking of light raw materials, which is carried out in the catalytic cracking reaction-regeneration system of the present application, and comprises:

[0060] 1) introducing preheated light crude oil from the lower part of the cracking reactor, contacting with the regenerated catalyst from the regenerator and performing catalytic cracking reaction from bottom to top to obtain a first reaction product and a first catalyst to be regenerated,

[0061] 2) introducing the coke raw material from the lower part of the coke generator, contacting it with the settler catalyst from the settler and / or the regenerated catalyst from the regenerator and performing a coke forming reaction to obtain a second reaction product and a second catalyst to be regenerated;

[0062] 3) introducing the first reaction product and the second reaction product into a separation system for separation to obtain dry gas, liquefied gas, pyrolysis gasoline, and pyrolysis heavy oil;

[0063] 4) The settler catalyst from the settler is transported to the regenerator for char regeneration, and the obtained regenerated catalyst is recycled.

[0064] The catalytic cracking method of the present invention is further described below in conjunction with the catalytic cracking reaction-regeneration system. The following description of the catalytic cracking method of the present application is also applicable to the catalytic cracking reaction-regeneration system of the present application, and vice versa.

[0065] Figure 2 The catalytic cracking reaction-regeneration system of the present application is shown, which includes:

[0066] Catalytic cracking reactor 100,

[0067] Coke generator 300,

[0068] Oil separation equipment 201,

[0069] settler 200, and

[0070] Regenerator 500.

[0071] like Figure 2As shown, the catalytic cracking reactor 100 is provided with a pre-lift gas inlet 101, a cracking raw material feed inlet 102 at the bottom, a catalyst inlet 103 at the bottom, and an oil agent outlet 104 at the top. In the present application, the catalyst inlet 103 of the cracking reactor 100 is fluidically connected to the first regenerated catalyst outlet 506 of the regenerator 500, so that at least a portion of the regenerated catalyst is circulated back to the catalytic cracking reactor 100. The oil agent outlet 104 of the cracking reactor is fluidically connected to the oil agent inlet of the oil agent separation device 201, so that the oil agent of the catalytic cracking reactor enters the oil agent separation device and is separated into a first reaction product and a first catalyst to be regenerated. After the first reaction product is collected by the gas collection chamber 202, it is introduced into the reaction product separation system (not shown) through the oil and gas pipeline 203 for separation to obtain various products, such as dry gas, liquefied gas, pyrolysis gasoline, and pyrolysis heavy oil.

[0072] In one embodiment, the catalytic cracking reactor 100 is coaxially arranged with the settler 200, and the oil separation device 201 is accommodated inside the settler 200, and the oil outlet 104 of the catalytic cracking reactor is connected to the oil separation device 201, so that the oil in the catalytic cracking reactor 100 enters the oil separation device 201 and is separated into a first reaction product and a first catalyst to be generated.

[0073] In one embodiment, the cracking reactor is selected from a riser and a downer, or a combination thereof, wherein the combination includes series and / or parallel connection. The riser is selected from one or more of a constant diameter riser, a constant linear velocity riser, and various variable diameter risers.

[0074] In one embodiment, the light raw material is selected from gaseous hydrocarbons with a carbon number of C4-C20 and light distillate oil, and 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 25-350°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.

[0075] 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 optionally a 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 comprises 10-100 wt%, preferably 50-90 wt%, of the total weight of the zeolite.

[0076] In the present application, the medium-pore zeolite and large-pore zeolite follow the 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.

[0077] 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 one or more mixtures 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.

[0078] 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.

[0079] In one embodiment, the conditions of the catalytic cracking reaction include: a reaction temperature of 550-750°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.

[0080] 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.

[0081] In one embodiment, the method further preferably comprises: introducing a C4 hydrocarbon fraction and / or a C5-C6 light gasoline fraction into the cracking reactor for catalytic cracking reaction.

[0082] In one embodiment, the catalytic cracking reactor 100 may be provided with a pre-lift gas inlet 101, a cracking raw material feed inlet 102 at the bottom, a C4 hydrocarbon or C5-C6 light gasoline fraction feed inlet 105, a catalyst inlet 103 at the bottom and an oil agent outlet 104 at the top.

[0083] In this application, the C4 hydrocarbon fraction refers to low-molecular-weight hydrocarbons that exist in gaseous form at room temperature and pressure and are primarily composed of the C4 fraction, including alkanes, alkenes, and alkynes with 4 carbon atoms in their molecules. This fraction can include both C4 hydrocarbon fraction-rich gaseous hydrocarbon products (e.g., liquefied petroleum gas) produced by the method of the present invention and C4 hydrocarbon fraction-rich gaseous hydrocarbons produced by other means. The C4 hydrocarbon fraction produced by the method of the present invention is preferred. The C4 hydrocarbon fraction is preferably an olefin-rich C4 hydrocarbon fraction, 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.

[0084] 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.

[0085] In one embodiment, the C4 hydrocarbons or C5-C6 light gasoline fraction is introduced at one or more points downstream of the point where the light feedstock is introduced into the cracking reactor.

[0086] like Figure 1 As shown, the catalytic cracking coke generator 300 of the present application is suitable for adjusting heat balance. The coke generator 300 includes, from bottom to top, a pre-lifting zone I, a coke generation reaction zone II, and an outlet zone III.

[0087] The coke generator 300 is equipped, from bottom to top, with a pre-lift gas inlet 301, a catalyst inlet 303, and a fuel oil inlet 302. The pre-lift gas inlet 301 is typically located in the pre-lift zone I, typically at the bottom of the zone. The catalyst inlet 303 can be located in the pre-lift zone I and / or the coke generation reaction zone II, but is typically located in the lower portion of the zone I, but above the pre-lift gas inlet 301, allowing the pre-lift gas to lift the incoming catalyst. This allows for pre-acceleration and pre-fluidization of the regenerated catalyst, improving its distribution and facilitating uniform contact and rapid mixing with the fuel oil.

[0088] The bottom of the regenerator 500 (eg Figure 2 The catalyst inlet 303 is connected to the coke generator 300, allowing the catalyst to enter the coke generator to form coke, thereby producing a coked catalyst. The top of the coke generator 300 is connected to the oil separation device 201, which separates the coked catalyst from the reaction oil and gas.

[0089] In one embodiment, the pre-lifting zone I, the coking reaction zone II, and the outlet zone III are connected in sequence, that is, the top of the pre-lifting zone I is connected to the coking reaction zone II, and the top of the coking reaction zone II is connected to the outlet zone III.

[0090] In the present application, the independently provided pre-lift gas inlet 301, regenerated catalyst inlet 303, and fuel oil inlet 302 of the coke maker 300 are located at different heights of the coke maker 300. Preferably, the coke maker 1 is provided with the pre-lift gas inlet 301, regenerated catalyst inlet 303, and fuel oil inlet 302 in order from bottom to top, and all are located at the lower portion of the coke maker 300.

[0091] In the present application, the reaction zone II of the coke generator 300 is a bubbling bed or a turbulent fluidized bed. In one embodiment, the reaction zone II is a hollow cylinder with an aspect ratio of 20:1 to 2:1.

[0092] In the present application, the coke maker may be provided with one or more fuel oil inlets 302, for example, one, two, or more. Each of the one or more fuel oil inlets may be independently located at the outlet of the coke maker's pre-elevation zone I, or at the bottom or sidewall of the coke generation reaction zone II. Further preferably, each of the fuel oil inlets 302 is independently located mid-upstream of the coke maker 300. Further preferably, each of the fuel oil inlets 302 is independently located at a distance h from the bottom of the coke maker, ranging from 5% to 15% of the coke maker's height.

[0093] In the present application, the fuel oil injected through the fuel oil inlet 302 may include straight-run distillate or secondary processed distillate. Preferably, the secondary processed distillate may be selected from a mixture of one or more of catalytic cracking diesel, catalytic cracking slurry oil, coker gasoline, coker diesel, and coker gas oil. In one embodiment, the amount of fuel oil (coking feedstock) injected into the coker may be 10-50 wt% of the feedstock oil into the cracking reactor.

[0094] In one embodiment, the pre-elevation zone I is hollow cylindrical with an aspect ratio of 10:1 to 2:1. In one embodiment, the outlet zone III is hollow cylindrical with an aspect ratio of 30:1 to 5:1. In one embodiment, the ratio of the inner diameters of the pre-elevation zone I, the coking reaction zone II, and the outlet zone III is 1:2:1 to 1:10:1.

[0095] In one embodiment, the coke generator 300 is located outside the settler 200 and arranged in parallel with the catalytic cracking reactor 100. The outlet area of the coke generator is connected to the oil-agent separation device 201, allowing the coke generator's material to enter the oil-agent separation device for separation into the second reaction product and the second spent catalyst (i.e., oil gas and coke-bearing catalyst). In one embodiment, the outlet end 304 of the coke generator 300 is connected to the inlet of the oil-agent separation device 201. In one embodiment, the oil-agent separation device 201 is housed within the settler 200, allowing the spent catalyst and coke-bearing catalyst separated by the oil-agent separation device 201 to settle within the settler 200.

[0096] In one embodiment, the settler 210 includes a stripping section 205 located at the lower portion of the settler. The stripping section 205 is configured to strip the collected catalyst from the catalytic cracking reactor and the coke generator (i.e., the first spent catalyst and the second spent catalyst, collectively referred to herein as the settler catalyst). The regenerator 500 is connected to the stripping section 205 so that the stripped settler catalyst is delivered to the regenerator 500. A stripping gas inlet 207 is provided at the lower portion of the stripping section 205 for inputting a stripping gas, such as water vapor.

[0097] In one embodiment, the stripping section 205 of the settler is provided with a first catalyst outlet 206 and a second catalyst outlet 208; the first catalyst outlet 206 of the settler is connected to the regenerator 500, so that at least a portion of the settler catalyst in the settler is transported to the regenerator. The bottom end of the pre-lifting zone of the coke generator and / or the bottom end of the coke generation reaction zone is configured to be connected to the second catalyst outlet 208 of the settler, and the second regenerated catalyst outlet 508 of the regenerator is connected to the pipeline connecting the settler and the coke generator, so that at least a portion of the regenerated catalyst of the regenerator can be mixed with at least a portion of the settler catalyst of the settler and then transported to the coke generator 300. In one embodiment, the catalyst inlet 303 of the coker is connected to the second catalyst outlet 208 of the settler through a pipeline, and the second regenerated catalyst outlet 508 of the regenerator is connected to the pipeline, so that at least a portion of the regenerated catalyst of the regenerator can be mixed with at least a portion of the settler catalyst of the settler in the pipeline, and then transported to the coker 300 through the catalyst inlet 303 of the coker.

[0098] In one embodiment, the coke generator 300 is fluidically connected to the oil-agent separation device 201. After the reaction oil and coke-bearing catalyst produced by the coke generator 300 are separated by the oil-agent separation device 201, the reaction oil and gas are collected in the gas collection chamber 202 and introduced into the reaction product separation system via the oil-gas pipeline 203 for recycling. The coke-bearing catalyst enters the stripping section 205 at the bottom of the settler 200. After stripping, it is introduced into the regenerator 500 via the standpipe (via the first catalyst outlet 206) for charring and heat release. In this application, the oil-agent separation device 201 can be a device familiar to those skilled in the art, such as a cyclone separator.

[0099] In one embodiment, the conditions of the coking reaction include: a reaction temperature of 460-560°C, a reaction time of 1-20 seconds, a catalyst-oil weight ratio of 3:1 to 30:1, a weight ratio of pre-lifting gas to coking raw material of 0.01:1 to 0.05:1, a linear velocity of 0.2-0.8 m / s, and a catalyst particle density of 300-700 kg / m3.

[0100] In one embodiment, the coke feedstock is the unit's own cracked heavy oil and secondary processed distillate, or a mixture thereof. Preferably, the secondary processed distillate can be selected from a mixture of one or more of catalytically cracked diesel, catalytically cracked diesel, catalytically cracked slurry oil, catalytically cracked slurry oil, coker gasoline, coker diesel, and coker gas oil. More preferably, the coke feedstock is the unit's own cracked heavy oil. In this application, "coke feedstock" and "coke fuel oil" are used interchangeably to refer to the fuel oil introduced into the coker for coking.

[0101] In one embodiment, the coke raw material is introduced into the coke maker at one location, or the coke raw material is introduced into the coke maker at more than one same or different location.

[0102] In one embodiment, the linear velocity of the reaction zone of the coke generator is 0.2 m / s to 1.2 m / s, and the catalyst particle density is 300 kg / m3 to 700 kg / m3.

[0103] In one embodiment, the pre-lift gas is selected from water vapor, nitrogen, dry gas, rich gas or C4 fraction or a mixture thereof, and the mass ratio of the pre-lift gas to fuel oil is 0.01:1 to 0.05:1.

[0104] In one embodiment, the fuel oil comprises straight-run distillate or secondary processed distillate. Preferably, the secondary processed distillate can be selected from a mixture of one or more of catalytic cracking diesel, coker gasoline, coker diesel and coker gas oil.

[0105] In one embodiment, the atomizing medium of the fuel oil can be selected from water vapor, nitrogen or a mixture thereof, and the mass ratio of the atomizing medium to the combustion oil is 0.01:1 to 0.5:1.

[0106] In one embodiment, the outlet temperature of the coke generator is 460-560°C.

[0107] In one embodiment, the catalyst to be generated (i.e., the settler catalyst) or the regenerated catalyst, or a mixture thereof, in the coke generator is contacted and reacted with the coke-generating raw material. In one embodiment, in the coke generator, the weight ratio of the settler catalyst from the settler to the regenerated catalyst from the regenerator may be 1:1 to 1:10.

[0108] like Figure 2 As shown, the regenerator 500 is used to regenerate the catalyst to be regenerated. The lower part is provided with an oxygen-containing gas inlet 501, a regenerated catalyst inlet 505 and two regenerated catalyst outlets 506 and an outlet 508. A cyclone separator 503 is provided inside and a flue gas outlet 504 is provided on the top.

[0109] like Figure 2As shown, the first regenerated catalyst outlet 506 is connected to the regenerated catalyst inlet 103 of the catalytic cracking reactor, so that at least a portion of the regenerated catalyst is circulated back to the catalytic cracking reactor 100. As described above, the catalyst inlet 303 of the coke generator is connected to the second catalyst outlet 208 of the settler via a pipeline, and the second regenerated catalyst outlet 508 of the regenerator is connected to the pipeline, so that at least a portion of the regenerated catalyst of the regenerator can be mixed with at least a portion of the settler catalyst of the settler in the pipeline, and then transported to the coke generator 300 through the catalyst inlet 303 of the coke generator, so that the catalyst can enter the coke generator to generate coke, thereby obtaining a coked catalyst.

[0110] The conditions of the regenerator are: regeneration temperature is 550-750°C, preferably 600-730°C, more preferably 650-700°C; gas superficial velocity is 0.5-3 m / s, preferably 0.8-2.5 m / s, more preferably 1-2 m / s; the average residence time of the catalyst to be regenerated is 0.6-3 minutes, preferably 0.8-2.5 minutes, more preferably 1-2 minutes.

[0111] In the catalytic cracking-regeneration system provided herein, the settler, oil separation equipment, regenerator, other devices, reaction product separation system, etc. may all be devices well known to those skilled in the art, and the connections between these devices may also be made in accordance with methods known in the art. For example, the oil separation equipment may include a cyclone separator and an outlet rapid separator.

[0112] In the present application, by setting up a coker, the fuel oil can be mixed with the catalyst under low-temperature, oxygen-free fluidized conditions, and a coking reaction occurs in the coker reaction zone having the characteristics of a bubbling bed or a turbulent fluidized bed. Not only is the coke selectivity high, but the coke is also evenly distributed on the catalyst, which is conducive to uniform combustion in the regeneration system.

[0113] In the present application, the coke-containing catalyst generated by the coke generator can be mixed with the coke-containing catalyst generated by the catalytic cracking reactor and enter the regeneration system. The coke on the catalyst can be fully burned and released heat under the action of high-temperature, oxygen-rich gas, supplying the heat required for the reaction without damaging the properties of the catalyst. This realizes the replenishment of coke source from the reaction system end, solves the thermal balance problem of the catalytic cracking device, and avoids the problem of local overheating caused by spraying fuel oil into the catalyst in the regenerator during the catalyst regeneration process.

[0114] The present application has a simple structure and only requires adaptive modification of the reactor system. The regeneration system still uses existing technology, is easy to implement, and has strong applicability. In particular, it is suitable for catalytic cracking units with light olefins and other chemical raw materials as the main target products. It can not only fundamentally solve the problem of heat balance, but also reduce the damage to the catalyst and regeneration system caused by the traditional method of spraying combustion oil, thereby saving catalyst costs and improving the economic benefits of the refinery.

[0115] 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.

[0116] Figure 2 A preferred embodiment of the catalytic cracking reaction system of the present application is given.

[0117] The pre-lift gas enters 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 lower part of the cracking reactor 100 through the catalyst inlet 103, mixes with the pre-lift gas, and moves upward, contacting the feedstock oil from the feedstock oil inlet 102 to cause a catalytic cracking reaction. The carbonized catalyst and the oil and gas generated by the reaction flow upward and enter the oil agent separation device 201 through the outlet 104.

[0118] The pre-lift gas enters the coker 300 from the bottom through the pre-lift gas inlet 301. The high-temperature regenerated catalyst from the regenerator and / or the catalyst to be regenerated from the settler enters the lower part of the coker 300 through the catalyst inlet 303. The catalyst mixes with the pre-lift gas and moves upward. It then comes into contact with the fuel oil from the fuel oil inlet 302 and enters the coker to generate a coking reaction. The catalyst with carbon and the oil and gas generated by the reaction flow upward and enter the oil-agent separation device 201 through the outlet 304.

[0119] After separation by the oil-agent separation device 201, the reaction oil and gas enter the gas collection chamber 202 and are introduced into the product separation system via the oil-gas pipeline 203. The separated coke-bearing catalyst enters the stripping section 205 of the settler 200. After being stripped by steam from the stripping gas inlet 207, a portion of the spent catalyst (settler catalyst) passes through the second catalyst outlet 208, where it is mixed with a portion of the regenerated catalyst from the second regenerated catalyst outlet 508 of the regenerator and then enters the coke generator through the catalyst inlet 303. A portion of the spent catalyst (settler catalyst) enters the regenerator 500 through the first catalyst outlet 206 and the spent catalyst inlet 505. The oxygen-containing gas from the oxygen-containing gas 501 enters the regenerator after passing through the gas distributor 502, where it contacts the coke-bearing catalyst, causing a complete combustion reaction and releasing heat. The regenerated catalyst is returned to the catalytic cracking reactor for recycling. The regenerated flue gas is recovered from the entrained catalyst by the cyclone separator 503 and then sent to the subsequent energy recovery system via the flue gas outlet 504.

[0120] Example

[0121] 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 coke feedstock was Anqing slurry oil obtained from the Anqing Petrochemical catalytic cracking unit. The properties of these two feedstocks are shown in Table 1.

[0122] Example 1

[0123] exist Figure 2 The system was tested, wherein the catalytic cracking reactor was a riser reactor;

[0124] The coke generator 300 used includes:

[0125] Pre-lifting zone I, with a length of 1 meter and an inner diameter of 0.2 meters;

[0126] Coke-generating reaction zone II is a turbulent bed reactor with a length of 3 meters and an inner diameter of 0.4 meters;

[0127] The outlet zone III has a length of 2 meters and an inner diameter of 0.2 meters.

[0128] The coke generator is provided with a pre-lift gas inlet 301 , a regenerated catalyst inlet 303 , and a fuel oil inlet 302 in sequence from bottom to top, and all are located at the lower part of the coke generator 300 .

[0129] The distance between the fuel oil inlet 302 and the bottom of the coke generator is independently 10% of the height of the coke generator.

[0130] A cracking reaction test of straight-run naphtha was carried out on a riser reactor. Preheated feedstock oil was introduced from the lower part of the cracking reactor, contacted with the regenerated catalyst from the regenerator, and subjected to a catalytic cracking reaction from bottom to top, obtaining an oil-agent mixture of reaction products and the regenerated catalyst. The oil-agent mixture entered a cyclone separator from the reactor outlet, where the reaction products and the regenerated catalyst were quickly separated. The reaction products were then cooled and collected.

[0131] The pre-lifting medium nitrogen enters the lower part of the coker and mixes with the mixed catalyst of the settler catalyst from the settler and the regenerated catalyst from the regenerator, then flows upward. The mixture of Anqing slurry oil (coking raw material) and atomized medium (water vapor) enters the coker through the fuel oil inlet, comes into contact with the hot regenerated catalyst and undergoes a coking reaction. The reaction products and the catalyst to be regenerated enter the cyclone separator from the coker outlet (outlet area), where they are quickly separated and the reaction products are collected after cooling.

[0132] The spent catalyst and carbon-carrying catalyst enter the stripping section of the settler under gravity. Steam strips the hydrocarbon products adsorbed on the spent catalyst. A portion of the stripped spent catalyst (settler catalyst) enters the regenerator, where it is regenerated by contact with air. A portion of the regenerated catalyst is returned to the catalytic cracking reactor for recycling. Another portion of the settler catalyst is mixed with a portion of the regenerated catalyst and returned to the coker. The settler catalyst recycled to the coker accounts for 90% of the total settler catalyst by weight, while the regenerated catalyst recycled to the coker accounts for 10% of the total regenerated catalyst. The operating conditions and product distribution are listed in Table 2.

[0133] From the results in Table 2, it can be seen that the methane yield is 13.72%, the ethylene yield is 18.63% by weight, the propylene yield is 19.59% by weight, the coke yield is 6.06%, and the total selectivity of ethylene and propylene is 45.51%.

[0134] Comparative Example 1

[0135] according to Figure 2 The experiment was conducted with reference to the process of Example 1, except that the coke generator was not turned on in Comparative Example 1, that is, the catalyst was regenerated as follows:

[0136] The spent catalyst enters the stripping section of the settler under gravity, where steam strips the hydrocarbon products adsorbed on the spent catalyst. The stripped catalyst then enters the regenerator, where it is regenerated by contact with air. Simultaneously, Anqing slurry is injected into the regenerator bed for combustion, replenishing the regenerator's heat. The regenerated catalyst is then returned to the reactor and coke generator for recycling. The operating conditions and product distribution are listed in Table 2.

[0137] From the results in Table 2, it can be seen that the methane yield was 14.76%, the ethylene yield was 18.01 wt%, the propylene yield was 18.40 wt%, the coke yield was 3.92%, and the total selectivity of ethylene and propylene was 43.46%.

[0138] 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 provide a heat source for the regenerator from the reaction system, have no effect on the regeneration system, and help maintain the physical and chemical properties of the catalyst.

[0139] 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.

[0140] 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.

[0141] 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.

[0142] Table 1 Properties of cracking reaction raw materials and coke raw materials

[0143] 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, mm 2 / s]]> 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 /

[0144] Table 2 Operating conditions and results of Examples and Comparative Examples

[0145] Example 1 Comparative Example 1 Cracking reactor conditions Cracking reactor outlet temperature, ℃ 675 675 Weight ratio of catalyst to raw material feed 30：1 30：1 Reaction time, seconds 2.5 2.5 Weight ratio of water vapor to raw material feed 0.3 0.3 Coke generator conditions Coke generator outlet temperature, ℃ 560 Weight ratio of catalyst to coke raw material feed 10 Reaction time, seconds 5 Weight ratio of water vapor to raw material feed 0.20 The proportion of raw coke feed to the cracking reactor feed, % 35 Regenerator conditions Temperature in regenerator, ℃ 720 720 The proportion of oil slurry feed in the regenerator to the feed of the cracking reactor, % 30 Product yield, weight % dry gas 38.55 39.44 Of which methane 13.72 14.76 Of which ethylene 18.63 18.01 Liquefied gas 37.21 36.49 Of which propylene 19.59 18.40 pyrolysis gasoline 16.01 16.23. Cracking heavy oil 2.17 3.92 coke 6.06 3.92 total 100.00 100.00 Methane selectivity, % 16.34 17.62 Total selectivity of ethylene and propylene, % 45.51 43.46

Claims

1. A catalytic cracking reaction-regeneration system comprising: Catalytic cracking reactor, coke generator, Oil separation equipment, settler, and Regenerator, The catalytic cracking reactor is provided with a pre-lift gas inlet, a regenerated catalyst inlet, a cracking feedstock oil inlet and an oil agent outlet; The catalytic cracking reactor is coaxially arranged with the settler, and the oil separation device is accommodated inside the settler. The oil outlet of the catalytic cracking reactor is connected to the oil separation device, so that the oil in the catalytic cracking reactor enters the oil separation device and is separated into a first reaction product and a first spent catalyst. The coke generator includes, from bottom to top, A pre-lift zone, wherein the pre-lift gas used is selected from steam, nitrogen, dry gas, rich gas or C4 fraction or a mixture thereof; a coking reaction zone, wherein the coking reaction zone is a bubbling fluidized bed or a turbulent fluidized bed, wherein the reaction temperature of the coking reaction zone is 460-560° C., the linear velocity is 0.2-0.8 m / s, and the catalyst particle density is 300-700 kg / m3; and Export Zone, wherein the top of the pre-lifting zone is connected to the coke-generating reaction zone, and the top of the coke-generating reaction zone is connected to the outlet zone; The coke generator is provided with one or more coke raw material inlets, wherein the one or more coke raw material inlets are independently provided at the outlet end of the pre-lifting zone, or at the bottom or side wall of the coke reaction zone; The coke generator is arranged outside the settler, and the outlet area of the coke generator is connected to the oil-agent separation device, so that the material of the coke generator enters the oil-agent separation device and is separated into the second reaction product and the second catalyst to be generated; The regenerator is provided with a first regenerated catalyst outlet and a second regenerated catalyst outlet, wherein the first regenerated catalyst outlet is connected to the regenerated 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 lower part of the settler is provided with a stripping section, and the stripping section of the settler is provided with a first catalyst outlet and a second catalyst outlet; the first catalyst outlet of the settler is communicated with the regenerator, so that at least a portion of the settler catalyst in the settler is transported to the regenerator; the bottom end of the pre-lifting zone of the coking reaction zone and / or the bottom end of the coking reaction zone of the coking reaction zone are configured to be communicated with the second catalyst outlet of the settler, and the second regenerated catalyst outlet of the regenerator is connected to the pipeline connecting the settler and the coking reaction zone, so that at least a portion of the regenerated catalyst of the regenerator and / or at least a portion of the settler catalyst of the settler are transported to the coking reaction zone.

2. The system according to claim 1, wherein: The coking device is provided with a pre-lift gas inlet, a catalyst inlet and one or more coking raw material inlets in sequence from bottom to top.

3. The system according to claim 2, characterized in that The distance between the one or more coke making raw material inlets and the bottom of the coke making vessel is independently 5% to 15% of the height of the coke making vessel.

4. The system according to claim 1, wherein: The coke-generating reaction zone is in the shape of a hollow cylinder, and its aspect ratio is 20:1 to 2:

1.

5. The system according to claim 4, characterized in that The pre-lifting area is a hollow cylinder with a length-to-diameter ratio of 10:1-2:1; The outlet area is a hollow cylinder with a length-to-diameter ratio of 30:1-5:

1.

6. The system according to claim 5, characterized in that The ratio of the inner diameters of the pre-lifting zone, the coking reaction zone and the outlet zone is 1:2:1 to 1:10:

2.

7. The system according to claim 5, characterized in that The catalytic cracking reactor is selected from one of a riser and a downer or a combination thereof, and the ratio of the inner diameter of the catalytic cracking reactor to that of the coking reaction zone is 0.1-0.5:

1.

8. A method for catalytic cracking of a light feedstock, the method being carried out in the catalytic cracking reaction-regeneration system according to any one of claims 1 to 7, the method comprising: 1) The preheated light feedstock is introduced from the lower part of the catalytic cracking reactor, contacts with the regenerated catalyst from the regenerator and undergoes a catalytic cracking reaction from bottom to top to obtain a first reaction product and a first catalyst to be regenerated. 2) contacting the coke-forming raw material with the settler catalyst from the settler and / or the regenerated catalyst from the regenerator to carry out a coking reaction to obtain a second reaction product and a second catalyst to be regenerated; 3) introducing the first reaction product and the second reaction product into a separation system for separation, 4) The settler catalyst from the settler is transported to the regenerator for char regeneration, and the regenerated catalyst is recycled.

9. The method according to claim 8, characterized in that The carbon number of the light raw material is 4-20.

10. The method according to claim 9, characterized in that 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.

11. The method according to claim 9, 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.

12. The method according to claim 11, characterized in that The C4 hydrocarbon fraction or the C5-C6 light gasoline fraction is introduced downstream of the feed position of the light raw material into the catalytic cracking reactor.

13. The method according to claim 10, characterized in that The conditions for the coking reaction include: a reaction time of 1-20 seconds, a catalyst-oil weight ratio of 3:1 to 30:1, and a weight ratio of pre-lifting gas to coking raw materials of 0.01:1 to 0.05:

1.

14. The method according to claim 10, characterized in that The raw material for coking is the cracked heavy oil produced by the device, or the secondary processed distillate oil, or a mixture thereof.

15. The method according to claim 14, characterized in that The secondary processed distillate oil is selected from a mixture of one or more of catalytic cracking diesel, catalytic cracking diesel, catalytic cracking slurry, catalytic cracking slurry, coker gasoline, coker diesel and coker gas oil.

16. The method according to claim 14, characterized in that The raw material for coking is the cracking heavy oil produced by the plant.

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