A method and system for producing light olefins by catalytic cracking of petroleum hydrocarbons

Abstract

The present application relates to a kind of petroleum hydrocarbon catalytic cracking production low carbon olefin method and system, the method is carried out in reactor system, reactor system includes fluidized bed reactor and upflow reactor, the oil gas outlet of fluidized bed reactor is connected with the oil gas inlet of upflow reactor;Method includes: (1) make raw oil and first catalyst contact in fluidized bed reactor and carry out first catalytic cracking reaction, obtain first oil agent mixture;(2) make first reaction oil gas and second catalyst contact in upflow reactor and carry out second catalytic cracking reaction, obtain second oil agent mixture;(3) separation second reaction oil gas obtains low carbon olefin.The present application first makes raw oil and first catalyst in fluidized bed reactor and carries out catalytic cracking reaction, replaces inactivated catalyst, then oil gas is reacted in the upflow reactor of higher temperature, and oil gas is converted into low carbon olefin with high selectivity, significantly improve the selectivity and yield of low carbon olefin.

Description

Technical Field

[0001] The present invention relates to the technical field of petroleum refining and petrochemical engineering, and in particular to a method and system for producing light olefins by catalytic cracking of petroleum hydrocarbons. Background Art

[0002] As an important secondary crude oil processing technology, catalytic cracking technology holds an irreplaceable position in the production of clean oil products and light olefins, characterized by its wide feedstock adaptability, high heavy oil conversion rate, and flexible product solutions. Recent development and trends in catalytic cracking technology for chemical feedstock production indicate that major oil companies and research institutions have shifted their focus from increasing light olefin yields to improving light olefin selectivity. In this process, researchers are developing new processes based on optimally matching hydrocarbon cracking performance with reaction temperature, reaction time, and catalyst performance.

[0003] The catalytic cracking unit is a self-heating device, where heat is transferred between the reaction and regeneration systems via the supported catalyst. This makes the regulation of reaction temperature inseparable from the circulation of the catalyst. In addition to providing the heat required for the catalytic cracking reaction, the catalyst also plays a crucial role in providing active centers for the reaction. As the cracking reaction occurs, the heat capacity of the catalyst particles decreases in tandem with the active centers. However, as the cracking reaction progresses, further cracking of small hydrocarbon molecules requires higher reaction temperatures. Researchers have also investigated how to best match reaction temperature and catalyst activity to the cracking properties of hydrocarbon molecules.

[0004] CN107557063 discloses a method for catalytic conversion of low-quality crude oil. This method utilizes a two-stage riser reactor. A portion of the spent catalyst is removed through a central expansion section, while a portion of the regenerated catalyst is added. This method allows for segmented control of the reaction depth and optimizes catalyst activity. However, this method uses a method that reduces the linear velocity and extends the reaction time in the expansion section to remove the catalyst. This increases the residence time of the oil and gas in the expansion section, significantly increases side reactions, and reduces the selectivity of the target product.

[0005] CN105368493 discloses a catalytic conversion method for producing high-octane gasoline. This method involves initially cracking the crude oil with a cooled regeneration agent at a relatively low temperature for a relatively short time. Subsequently, a higher temperature regeneration agent is added, and the cracking reaction is continued at a temperature 5-100°C higher than that in the initial reaction zone for a longer reaction time. This method controls the cracking depth by separately controlling the reaction severity in each riser reactor reaction zone. However, in this method, the carbonized catalyst after reaction in the initial reaction zone is completely transferred to the main reaction zone, which increases the proportion of hydrocarbons reacting on the deactivated catalyst and reduces the selectivity of the target product.

[0006] CN107337574 discloses a catalytic conversion method for producing olefins by cracking light hydrocarbons. This method uses spent catalyst drawn from a stripper or reacted catalyst drawn from a reactor to return to a pre-contact zone. After the light hydrocarbon feedstock is vaporized in the pre-contact zone, it enters the main reaction zone where it contacts the regenerated catalyst for high-temperature cracking. This method combines low-temperature pre-gasification with high-temperature cracking, optimizing the reactor's temperature distribution. However, due to the low reaction temperature in the pre-contact zone, this method not only vaporizes the light hydrocarbons but also hinders cracking reactions. This significantly reduces the catalyst-to-oil ratio in the main reaction zone, resulting in a low yield of low-carbon olefins from the cracking of the light hydrocarbons.

[0007] CN110240932 discloses a multi-stage fluidized catalytic reaction method and reactor for petroleum hydrocarbons. This method involves contacting and reacting feedstock oil and regenerated catalyst in a first reaction zone. After some of the catalyst is swirled out, the oil and gas continue through a delivery pipe to a second reaction zone where they react with a second catalyst replenished in a third reaction zone. The oil and gas in the first reaction zone continue to undergo cracking reactions under the new catalyst. Light hydrocarbons and light cycle oil react with the second catalyst in the third reaction zone, and the resulting oil enters the second reaction zone where it continues to undergo catalytic cracking. This method enables catalyst replacement, gradient control of the reaction temperature, and control of the carbon content of the regenerated catalyst. However, because the third reaction zone is located below the second reaction zone, the oil and gas in the first reaction zone can undergo severe thermal cracking reactions as they pass through the high-temperature third reaction zone, resulting in the production of large amounts of dry gas.

[0008] CN108753356 discloses a multi-stage countercurrent catalytic cracking / cracking system and method. This method utilizes at least two descending fluidized bed reactors and at least two gas-solid rapid separation devices arranged in a stepped configuration. The discharge port of each descending fluidized bed reactor is connected to the gas-solid mixed phase inlet of the corresponding gas-solid rapid separation device, and the gas outlet of the corresponding gas-solid rapid separation device of each descending fluidized bed reactor is connected to the feed port of the corresponding descending fluidized bed reactor of the previous stage. This method can provide different temperature fields and catalyst activity fields for each stage of the reaction, which is beneficial for improving the selectivity of hydrocarbon catalytic cracking / cracking. However, this method cannot flexibly control the temperature and catalyst activity according to the hydrocarbon cracking performance, which has significant operational limitations.

[0009] In the catalytic cracking reaction process, how to match the cracking performance of hydrocarbon molecules, flexibly control the reaction temperature and catalyst activity, and thus improve the selectivity and yield of light olefins is a technical problem that needs to be solved urgently. Summary of the Invention

[0010] The purpose of the present invention is to provide a method and system for producing light olefins by catalytic cracking of petroleum hydrocarbons, so as to improve the selectivity and yield of light olefins.

[0011] In a first aspect, the present invention relates to a method for producing light olefins by catalytic cracking of petroleum hydrocarbons, the method being carried out in a reactor system, the reactor system comprising a fluidized bed reactor and an ascending reactor, the oil and gas outlet of the fluidized bed reactor being connected to the oil and gas inlet of the ascending reactor; the method comprising the following steps: (1) contacting crude oil with a first catalyst in the fluidized bed reactor to perform a first catalytic cracking reaction to obtain a first oil-agent mixture; separating the first oil-agent mixture to obtain a first reaction oil and gas and a first catalyst to be regenerated; (2) contacting the first reaction oil and gas with a second catalyst in the ascending reactor to perform a second catalytic cracking reaction to obtain a second oil-agent mixture; separating the second oil-agent mixture to obtain a second reaction oil and gas and a second catalyst to be regenerated; (3) separating the second reaction oil and gas to obtain light olefins; the outlet temperature of the ascending reactor being 10-100°C higher than the outlet temperature of the fluidized bed reactor.

[0012] Optionally, the method further comprises: stripping and regenerating the second spent catalyst to obtain a regenerated catalyst.

[0013] Optionally, the method further comprises: stripping and heating the first spent catalyst to obtain a heated catalyst having a temperature of 600-670°C.

[0014] Optionally, the second catalyst is the regenerated catalyst and / or the heated catalyst.

[0015] Optionally, the first catalyst is the regenerated catalyst and / or the cooled regenerated catalyst.

[0016] Optionally, the gas linear velocity of the fluidized bed reactor is lower than 1 m / s, and the gas linear velocity of the upward reactor is higher than 3 m / s.

[0017] Optionally, the outlet temperature of the fluidized bed reactor is 500-650°C, and the mass space velocity is 2-16h -1 The weight ratio of the first catalyst to the feedstock oil is (1-50):1; preferably, the outlet temperature of the fluidized bed reactor is 530-600°C, and the mass space velocity is 4-12h -1 , the weight ratio of the first catalyst to the raw oil is (10-30):1.

[0018] Optionally, the outlet temperature of the upward reactor is 550-700°C, the oil and gas residence time is 0.3-5s, and the weight ratio of the second catalyst to the feedstock oil is (5-50):1; preferably, the outlet temperature of the upward reactor is 560-650°C, the oil and gas residence time is 0.5-3.0s, and the weight ratio of the second catalyst to the feedstock oil is (10-30):1.

[0019] Optionally, the feedstock oil is selected from a combination of one or more of crude oil, atmospheric wax oil, vacuum wax oil, atmospheric residue oil, vacuum residue oil, deasphalted oil, hydrogenated heavy oil and coker wax oil; or is selected from partial fractions or full fractions of one or more of coal liquefaction oil, oil sands oil, shale oil, synthetic oil and animal and plant oils and fats.

[0020] In the second aspect, the present invention relates to a system for producing light olefins by catalytic cracking of petroleum hydrocarbons, the system comprising a fluidized bed reactor and an ascending reactor, the oil and gas outlet of the fluidized bed reactor being connected to the oil and gas inlet of the ascending reactor; a first catalyst delivery pipe and a raw oil feed nozzle are respectively provided at the bottom of the fluidized bed reactor, and a first catalyst output pipe to be generated is provided at the lower part of the fluidized bed reactor; a second catalyst delivery pipe is provided at the bottom of the ascending reactor, a settler is connected to the top of the ascending reactor, an oil and gas delivery pipe is provided at the upper part of the settler, and a second catalyst delivery pipe to be generated is provided at the lower part of the settler; the system is further provided with an oil and gas separation device connected to the oil and gas delivery pipe; the ascending reactor and the fluidized bed reactor are configured so that the outlet temperature of the ascending reactor is 10-100°C higher than the outlet temperature of the fluidized bed reactor.

[0021] Optionally, the system further comprises a first stripper and a heater, wherein the solid inlet of the first stripper is connected to the first generated catalyst output pipe, and the solid outlet of the first stripper is connected to the inlet of the heater; the temperature of the heater is configured to be 600-670°C; and the outlet of the heater is connected to the second catalyst delivery pipe.

[0022] Optionally, the system further includes a second stripper and a regenerator, the solid inlet of the second stripper is connected to the second regenerated catalyst delivery pipe, the second stripper is connected to the regenerator via a post-stripping catalyst delivery pipe arranged at its lower part, and the second stripper is also provided with a water vapor delivery pipe; the outlet of the regenerator is respectively connected to the first catalyst delivery pipe and the second catalyst delivery pipe.

[0023] Optionally, the upward reactor is a single or composite reactor in a riser reactor with a constant diameter or a variable diameter, or a fast bed reactor.

[0024] Beneficial effects:

[0025] The present invention first allows the crude oil and the first catalyst to undergo a catalytic cracking reaction in a fluidized bed reactor to replace the deactivated catalyst, and then allows the oil and gas to react in an upward reactor at a higher temperature to convert the oil and gas into light olefins with high selectivity, significantly improving the selectivity and yield of light olefins. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a structural schematic diagram of one specific embodiment of the system for producing low-carbon olefins by catalytic cracking of petroleum hydrocarbons according to the present application;

[0027] Explanation of reference numerals

[0028] 1 fluidized bed reactor; 2 upflow reactor; 3 settler; 4 second stripper;

[0029] 11 first catalyst delivery pipe; 12 feed oil feed nozzle;

[0030] 13 first spent catalyst output pipe; 21 second catalyst delivery pipe;

[0031] 31 oil gas delivery pipe; 41 steam delivery pipe;

[0032] 42 stripped catalyst delivery pipe. DETAILED DESCRIPTION

[0033] The present application will be further described by the accompanying drawings and examples. The features and advantages of the present application will become more apparent from the description of the application.

[0034] The term "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations. Although various aspects of an implementation can be described herein as being a preferred or advantageous implementation, no inference should be drawn that other aspects necessarily are inferior or inferior to other aspects. The various aspects described herein can be implemented in any of numerous ways, as will be apparent to one of ordinary skill in the art. Examples of specific implementations and features following, described and / or illustrated herein can be implemented with respect to either the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, sixteenth, seventeenth, eighteenth, nineteenth, twentieth, twenty-first, twenty-second, twenty-third, twenty-fourth, twenty-fifth, twenty-sixth, twenty-seventh, twenty-eighth, twenty-ninth, thirtieth, thirty-first, thirty-second, thirty-third, thirty-fourth, thirty-fifth, thirty-sixth, thirty-seventh, thirty-eighth, thirty-ninth, or fortieth aspect of the application, or any combination thereof. Techniques and technologies from any of these may be readily combined with features of other aspects.

[0035] Moreover, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as there is no conflict.

[0036] In a first aspect, the present application relates to a method for producing low-carbon olefins by catalytic cracking of petroleum hydrocarbons, which is carried out in a reactor system comprising a fluidized bed reactor and an upflow reactor, wherein the oil gas outlet of the fluidized bed reactor is in communication with the oil gas inlet of the upflow reactor; the method comprises the following steps: (1) contacting a feed oil with a first catalyst in the fluidized bed reactor to carry out a first catalytic cracking reaction to obtain a first oil catalyst mixture; separating the first oil catalyst mixture to obtain a first reaction oil gas and a first spent catalyst; (2) contacting the first reaction oil gas with a second catalyst in the upflow reactor to carry out a second catalytic cracking reaction to obtain a second oil catalyst mixture; separating the second oil catalyst mixture to obtain a second reaction oil gas and a second spent catalyst; (3) separating the second reaction oil gas to obtain low-carbon olefins; the outlet temperature of the upflow reactor is 10-100°C higher than the outlet temperature of the fluidized bed reactor.

[0037] In a second aspect, the present invention relates to a system for producing light olefins by catalytic cracking of petroleum hydrocarbons, such as Figure 1 As shown, the system includes a fluidized bed reactor 1 and an ascending reactor 2, the oil and gas outlet of the fluidized bed reactor 1 is connected to the oil and gas inlet of the ascending reactor 2; the bottom of the fluidized bed reactor 1 is respectively provided with a first catalyst delivery pipe 11 and a raw oil feed nozzle 12, and the lower part of the fluidized bed reactor 1 is provided with a first catalyst output pipe 13 to be generated; the bottom of the ascending reactor 2 is provided with a second catalyst delivery pipe 21, the top of the ascending reactor 2 is connected to a settler 3, the upper part of the settler 3 is provided with an oil and gas delivery pipe 31, and the lower part of the settler 3 is provided with a second catalyst delivery pipe to be generated; the system is also provided with an oil and gas separation device connected to the oil and gas delivery pipe 31; the ascending reactor 2 and the fluidized bed reactor 1 are configured so that the outlet temperature of the ascending reactor 2 is 10-100°C higher than the outlet temperature of the fluidized bed reactor 1.

[0038] It should be noted that the method of the first aspect of the present invention is applicable to the system of the second aspect of the present invention. The raw oil enters the fluidized bed reactor 1 through the raw oil feed nozzle 12 under the water vapor atomizing medium, and the first catalyst enters the fluidized bed reactor 1 through the first catalyst delivery pipe 11, and then undergoes a first catalytic cracking reaction; the separated first catalyst to be regenerated enters the first catalyst to be regenerated output pipe 13; the separated first reaction oil and gas flows upward into the upward reactor 2, and the second catalyst enters the upward reactor 2 through the second catalyst delivery pipe 21, and then undergoes a second catalytic cracking reaction to obtain a second oil-agent mixture; the second oil-agent mixture flows to the settler 3 and is separated by a cyclone to obtain the second reaction oil and gas and the second catalyst to be regenerated; the second reaction oil and gas flows through the oil and gas delivery pipe 31 to the oil and gas separation device (oil and gas distillation separation device) for separation to obtain dry gas, liquefied gas, gasoline, diesel and oil slurry; the separated second catalyst to be regenerated enters the second catalyst delivery pipe.

[0039] It should be noted that during the catalytic cracking process, heavy components such as colloids and asphaltenes in the raw materials are preferentially adsorbed on the active centers of the catalyst, but this part of the colloids and asphaltenes often covers the active centers in the form of coke, resulting in reduced catalyst activity and reduced selectivity of cracking of other hydrocarbons. The present invention first pre-cracks hydrocarbons in a fluidized bed reactor with a high catalyst density to generate light olefins and a large amount of olefin-rich intermediate components, and then separates or replaces the deactivated first catalyst to be regenerated, adopts a riser reactor with a higher reaction temperature and a lower catalyst density, and introduces a second catalyst to further convert the intermediate components into light olefins with high selectivity, while inhibiting the further conversion of the light olefins that have been generated. The method provided by the present invention is conducive to making the reaction temperature and catalyst density more compatible with the cracking performance of different hydrocarbon molecules in the catalytic cracking process, and the yield and selectivity of light olefins are higher.

[0040] According to an embodiment of the first aspect of the present invention, the method further comprises: stripping and regenerating the second spent catalyst to obtain a regenerated catalyst.

[0041] According to an embodiment of the first aspect of the present invention, the method further comprises: stripping and heating the first spent catalyst to obtain a heated catalyst having a temperature of 600-670°C.

[0042] According to one embodiment of the first aspect of the present invention, the second catalyst is the regenerated catalyst and / or the heated catalyst.

[0043] According to one embodiment of the first aspect of the present invention, the first catalyst is the regenerated catalyst and / or the cooled regenerated catalyst.

[0044] According to one embodiment of the second aspect of the present invention, the system further comprises a first stripper and a heater, wherein the solid inlet of the first stripper is connected to the first spent catalyst output pipe 13, and the solid outlet of the first stripper is connected to the inlet of the heater; the temperature of the heater is configured to be 600-670°C; and the outlet of the heater is connected to the second catalyst delivery pipe 21.

[0045] According to one embodiment of the second aspect of the present invention, the system further comprises a second stripper 4 and a regenerator, wherein the solid inlet of the second stripper 4 is connected to the second regenerated catalyst delivery pipe, the second stripper 4 is connected to the regenerator via a post-stripping catalyst delivery pipe 42 provided at the lower portion thereof, and the second stripper 4 is further provided with a steam delivery pipe 41; the outlet of the regenerator is respectively connected to the first catalyst delivery pipe 11 and the second catalyst delivery pipe 21.

[0046] It should be noted that the first stripper and the second stripper can be the same stripper or different strippers. In other words, the fluidized bed reactor can be independently equipped with a stripper for stripping the first spent catalyst, and the ascending reactor can be independently equipped with a stripper for stripping the second spent catalyst, or they can share a stripper.

[0047] It should be noted that the second regenerated catalyst entering the second regenerated catalyst delivery pipe can enter the second stripper 4 for stripping. Steam is introduced into the second stripper 4 through the steam delivery pipe 41 to strip the catalyst. The stripped catalyst can then enter the regenerator for regeneration to obtain regenerated catalyst. The resulting regenerated catalyst can be respectively introduced into the fluidized bed reactor 1 and the ascending reactor 2 via the first catalyst delivery pipe 11 and the second catalyst delivery pipe 21 to serve as the first catalyst and the second catalyst, respectively.

[0048] In addition to using the regenerated catalyst as the second catalyst, the first regenerated catalyst that has been stripped and heated, i.e., the heated catalyst, can also be used as the second catalyst. Specifically, the first regenerated catalyst entering the first regenerated catalyst outlet pipe 13 can be stripped in the first stripper and then heated in the heater to obtain a heated catalyst at 600-670°C. Using this heated catalyst as the second catalyst has the following advantages:

[0049] The first reaction oil and gas entering upward reactor 2 is a mixture of the olefin-rich intermediate product after the first catalytic cracking reaction of the feedstock under the catalysis of the first catalyst and the light olefins generated in the first catalytic cracking reaction. If the second catalytic cracking reaction is carried out in the presence of an overly active catalyst, the light olefins generated in the first catalytic cracking reaction are easily converted into substances such as dry gas and coke. The first spent catalyst at 600-670°C after stripping and heating, i.e., the heated catalyst, has only undergone a heating process and has not been regenerated. Therefore, due to its overactivity, it will not convert the already generated light olefins into byproducts such as dry gas and coke. Therefore, directly using the first spent catalyst at 600-670°C after stripping and heating, i.e., the heated catalyst, as the second catalyst in contact with the first reaction oil and gas for the second catalytic cracking reaction can significantly improve the yield and selectivity of light olefins.

[0050] Therefore, as a preferred embodiment, the first spent catalyst is stripped and heated and returned to the system for recycling as the second catalyst, and the regenerated catalyst of the second spent catalyst is stripped and regenerated and returned to the system for recycling as the first catalyst, forming a good self-circulating system and obtaining a high yield and selectivity of light olefins.

[0051] According to an embodiment of the second aspect of the present invention, the upward reactor is a single or composite reactor among a riser reactor with a constant diameter or a variable diameter, or a fast bed reactor.

[0052] It should be noted that the reactor described above can be used as an upward reactor and can be easily and quickly assembled with a fluidized bed reactor to obtain the system of the present invention, which is suitable for large-scale industrial promotion and use.

[0053] According to one embodiment of the first aspect of the present invention, the linear velocity of the gas in the fluidized bed reactor is less than 1 m / s, and the linear velocity of the gas in the ascending reactor is greater than 3 m / s. By comprehensively controlling the linear velocity of the gas in the fluidized bed reactor and the ascending reactor, the system of the present invention can operate more stably and efficiently.

[0054] According to one embodiment of the first aspect of the present invention, the outlet temperature of the fluidized bed reactor is 500-650°C, and the mass space velocity is 2-16h -1 The weight ratio of the first catalyst to the feedstock oil is (1-50):1; preferably, the outlet temperature of the fluidized bed reactor is 530-600°C, and the mass space velocity is 4-12h -1 , the weight ratio of the first catalyst to the raw oil is (10-30):1.

[0055] It should be noted that the above-mentioned regulation of the outlet temperature, mass space velocity and catalyst-oil ratio of the fluidized bed reactor can enable the feedstock oil to better contact with the first catalyst in the fluidized bed reactor to carry out the first catalytic cracking reaction.

[0056] According to one embodiment of the first aspect of the present invention, the outlet temperature of the upward reactor is 550-700°C, the oil and gas residence time is 0.3-5s, and the weight ratio of the second catalyst to the feed oil is (5-50):1; preferably, the outlet temperature of the upward reactor is 560-650°C, the oil and gas residence time is 0.5-3.0s, and the weight ratio of the second catalyst to the feed oil is (10-30):1.

[0057] It should be noted that the above-mentioned regulation of the outlet temperature, oil-gas residence time, and catalyst-oil ratio of the upward reactor can enable the first reaction oil and gas to better contact with the second catalyst in the upward reactor to carry out the second catalytic cracking reaction, thereby further improving the yield and selectivity of light olefins.

[0058] According to one embodiment of the first aspect of the present invention, the feedstock oil is selected from a combination of one or more of crude oil, atmospheric wax oil, vacuum wax oil, atmospheric residue oil, vacuum residue oil, deasphalted oil, hydrogenated heavy oil and coker wax oil; or is selected from a partial fraction or full fraction of one or more of coal liquefaction oil, oil sands oil, shale oil, synthetic oil and animal and plant oils and fats.

[0059] It should be noted that crude oil, atmospheric gas oil, vacuum gas oil, etc. are petroleum hydrocarbons, while coal liquefaction oil, oil sands oil, shale oil, etc. are mineral oils. The method of producing light olefins by catalytic cracking of petroleum hydrocarbons of the present invention has wide applicability, can effectively catalytically crack a variety of feedstock oils to obtain high light olefin yields and selectivities, and does not require pre-separation of the feedstock oils. The method is simple and energy-efficient.

[0060] The present invention is further described in detail below by way of examples, but the present invention is not limited thereto.

[0061] The catalytic cracking catalyst used in the Examples and Comparative Examples was produced by the Qilu Branch of Sinopec Catalyst Co., Ltd., under the trade designation EP-3B. This catalyst contains a ZSP molecular sieve with an average pore size of less than 0.7 nanometers and an ultrastable Y-type molecular sieve. Prior to use, the catalyst was hydrothermally aged at 800°C with saturated steam for 17 hours. The main physicochemical properties of the catalyst are shown in Table 1. The properties of the feedstock oils used in the Examples and Comparative Examples are listed in Table 2.

[0062] Table 1

[0063]

[0064] Table 2

[0065]

[0066]

[0067] In the following examples and comparative examples, the calculation method and the like are described as follows:

[0068] The product distribution values ​​of dry gas, liquefied gas and gasoline in the table represent mass fractions; among them, the dry gas yield is the sum of the mass fractions of H2, CH4 and C2 hydrocarbons in the product; the liquefied gas yield is the sum of the mass fractions of C3 and C4 hydrocarbons in the product; the gasoline yield is the yield of liquids with a boiling point less than 221°C in the product; the diesel yield is the yield of liquids with a boiling point of 221°C to 331°C in the product; and the slurry oil yield is the yield of liquids with a boiling point greater than 331°C in the product.

[0069] Conversion rate (%) = 100% - diesel yield - slurry yield;

[0070] Triene yield (%) = ethylene yield + propylene yield + butene yield;

[0071] Triene selectivity = triene yield ÷ conversion rate.

[0072] Example 1

[0073] The experiment was carried out using a modified medium-sized unit with continuous reaction-regeneration operation, such as Figure 1 As shown in the figure, the fluidized bed reactor 1 in this medium-sized device has an inner diameter of 80 mm and a height of 600 mm. The riser reactor, serving as the upward reactor 2, has an inner diameter of 36 mm and a length of 4600 mm. A high-temperature regenerated catalyst at 670°C is introduced into the bottom of the fluidized bed reactor via a regeneration inclined tube and a first catalyst delivery tube 11. Preheated feedstock oil, atomized with steam, enters the fluidized bed reactor 1 through a feedstock oil feed nozzle 12, where it contacts the hot regenerated catalyst for a catalytic cracking reaction. The reacted first regenerated catalyst is stripped and then introduced into a heater to heat the temperature to 620°C. The reaction oil vapor further enters the riser reactor, where it contacts the first regenerated catalyst (serving as the second catalyst) heated to 620°C after stripping, continuing the cracking reaction. The reacted oil is introduced into an oil separation system. The separated reaction oil vapor is introduced into a product separation system to separate it into gaseous and liquid products. The separated second regenerated catalyst is similarly stripped and then introduced into a regenerator for char regeneration. The regenerated catalyst (serving as the first catalyst) is returned to the reactor for recycling via the regeneration inclined tube and the first catalyst delivery tube 11. Medium-sized devices use electric heating to maintain the temperature of the reaction-regeneration system.

[0074] The main operating conditions and results are listed in Table 3.

[0075] Example 2

[0076] Catalytic cracking was carried out to produce light olefins using the same raw materials, catalysts, equipment and reaction conditions as in Example 1, except that the second catalyst used was a 620°C regenerated catalyst.

[0077] The main operating conditions and results are listed in Table 3.

[0078] Comparative Example 1

[0079] The catalytic cracking reaction was carried out under the same feedstock oil, catalyst and reaction conditions as in Example 1, except that the outlet temperature of the riser reactor was lower than the reaction temperature of the fluidized bed reactor.

[0080] The main operating conditions and results are listed in Table 3.

[0081] Table 3

[0082]

[0083]

[0084] Note: Riser reactor reaction time refers to the oil and gas residence time in the riser reactor.

[0085] As shown in Table 3, Examples 1 and 2, using the method and system for producing light olefins through catalytic cracking of petroleum hydrocarbons provided by the present invention, achieved not only high triene yields but also high triene selectivity. In particular, in Example 1, using the stripped and heated first spent catalyst as the second catalyst resulted in even higher triene yields and selectivity.

[0086] 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.

[0087] 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.

[0088] 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.

Claims

1. A method for producing light olefins by catalytic cracking of petroleum hydrocarbons, wherein: The method is carried out in a reactor system comprising a fluidized bed reactor and an ascending reactor, wherein the oil and gas outlet of the fluidized bed reactor is connected to the oil and gas inlet of the ascending reactor; the method comprises the following steps: (1) contacting the feedstock oil with the first catalyst in the fluidized bed reactor to perform a first catalytic cracking reaction to obtain a first oil-agent mixture; and separating the first oil-agent mixture to obtain a first reaction oil gas and a first spent catalyst; (2) contacting the first reaction oil and gas with a second catalyst in the upward reactor to perform a second catalytic cracking reaction to obtain a second oil-agent mixture; separating the second oil-agent mixture to obtain a second reaction oil and gas and a second catalyst to be regenerated; (3) separating the second reaction oil and gas to obtain light olefins; The outlet temperature of the upward reactor is 10-100° C. higher than the outlet temperature of the fluidized bed reactor; The method further comprises: stripping and heating the first spent catalyst to obtain a heated catalyst having a temperature of 600-670° C., and the second catalyst is the heated catalyst.

2. The method according to claim 1, wherein The method further comprises: stripping and regenerating the second spent catalyst to obtain a regenerated catalyst.

3. The method according to claim 2, wherein: The first catalyst is the regenerated catalyst and / or the cooled regenerated catalyst.

4. The method according to claim 1, wherein The gas linear velocity of the fluidized bed reactor is lower than 1 m / s, and the gas linear velocity of the upward reactor is higher than 3 m / s.

5. The method according to claim 1, wherein The outlet temperature of the fluidized bed reactor is 500-650°C, and the mass space velocity is 2-16h -1 , the weight ratio of the first catalyst to the raw oil is (1-50):

1.

6. The method according to claim 5, wherein: The outlet temperature of the fluidized bed reactor is 530-600°C, and the mass space velocity is 4-12h -1 , the weight ratio of the first catalyst to the raw oil is (10-30):

1.

7. The method according to claim 1, wherein The outlet temperature of the upward reactor is 550-700° C., the oil and gas residence time is 0.3-5 s, and the weight ratio of the second catalyst to the feedstock oil is (5-50):

1.

8. The method according to claim 7, wherein: The outlet temperature of the upward reactor is 560-650° C., the oil and gas residence time is 0.5-3.0 s, and the weight ratio of the second catalyst to the feedstock oil is (10-30):

1.

9. The method according to claim 1, wherein The raw oil is selected from one or more of crude oil, atmospheric wax oil, vacuum wax oil, atmospheric residue oil, vacuum residue oil, deasphalted oil, hydrogenated heavy oil and coker wax oil; or is selected from partial fractions or full fractions of one or more of oil sands oil, shale oil, synthetic oil and animal and plant oils and fats.

10. The method according to claim 1, wherein The raw oil is selected from a partial fraction or a full fraction of coal liquefaction oil.

11. A system for producing light olefins by catalytic cracking of petroleum hydrocarbons for implementing the method according to any one of claims 1 to 10, wherein: The system comprises a fluidized bed reactor (1) and an ascending reactor (2), wherein the oil and gas outlet of the fluidized bed reactor (1) is connected to the oil and gas inlet of the ascending reactor (2); The bottom of the fluidized bed reactor (1) is provided with a first catalyst delivery pipe (11) and a raw oil feed nozzle (12), and the lower part of the fluidized bed reactor (1) is provided with a first catalyst output pipe (13); The bottom of the upward reactor (2) is provided with a second catalyst delivery pipe (21), the top of the upward reactor (2) is connected to a settler (3), the upper part of the settler (3) is provided with an oil and gas delivery pipe (31), and the lower part of the settler (3) is provided with a second catalyst delivery pipe to be generated; The system is further provided with an oil-gas separation device connected to the oil-gas delivery pipe (31); The upward reactor (2) and the fluidized bed reactor (1) are configured so that the outlet temperature of the upward reactor (2) is 10-100° C. higher than the outlet temperature of the fluidized bed reactor (1); The system further comprises a first stripper and a heater, wherein the solid inlet of the first stripper is connected to the first spent catalyst output pipe (13), and the solid outlet of the first stripper is connected to the inlet of the heater; The temperature of the heater is configured to be 600-670°C; The outlet of the heater is communicated with the second catalyst delivery pipe (21).

12. The system according to claim 11, wherein The system further comprises a second stripper (4) and a regenerator, wherein the solid inlet of the second stripper (4) is connected to the second regenerated catalyst delivery pipe, the second stripper (4) is connected to the regenerator via a stripped catalyst delivery pipe (42) provided at the lower portion thereof, and the second stripper (4) is further provided with a steam delivery pipe (41); The outlet of the regenerator is communicated with the first catalyst delivery pipe (11).

13. The system according to claim 11, wherein: The upward reactor is a single or composite reactor in a riser reactor with a constant diameter or a variable diameter, or a fast bed reactor.

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