Method for promoting long-period continuous operation of an alkylation main reactor and application thereof

Abstract

The application discloses a method for promoting long-period continuous operation of an alkylation main reactor and application thereof, and the method comprises the following steps: arranging an on-line replaceable pre-reactor in front of the alkylation main reactor along a material flow direction, feeding aromatic hydrocarbon raw materials and olefin raw materials into the pre-reactor, discharging materials from the pre-reactor into the alkylation main reactor, and feeding the olefin raw materials into the alkylation main reactor independently; wherein, a silicon-aluminum catalyst I is filled in the pre-reactor, a silicon-aluminum catalyst II is filled in the main reactor, and the silicon-aluminum ratio of the silicon-aluminum catalyst I is less than the silicon-aluminum ratio of the silicon-aluminum catalyst II. The pre-reactor has the function of a guard bed, can indicate the operation state of the guard bed, and guarantees long-period normal operation of the main reactor.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of alkylation, and particularly relates to long-period continuous operation of an alkylation main reactor, and in particular to a method for promoting long-period continuous operation of an alkylation main reactor and application thereof. BACKGROUND

[0002] According to the prior art, impurities in the benzene raw material in the alkylation reaction are prone to poisoning the catalyst, and these substances can further react with the raw material, or block the catalyst pores and destroy the catalyst, or cause the catalyst structure to change, resulting in a decrease in the performance of the catalyst and difficulty in maintaining the service life. In industry, in order to prevent the catalyst from losing activity due to the influence of toxic substances such as basic nitrogen compounds, methanol and water in the raw material, the current process adopts the technology of a multi-stage reaction guard bed to protect the catalyst in the main reactor.

[0003] However, the prior art needs to continuously detect the content of each impurity in the outlet raw material to determine the state of the adsorbent, and periodically switch the regeneration. This way of continuously detecting impurities is very cumbersome. The running time of the guard bed is often determined by experience, and at the same time, the detection of the guard bed in the prior art is prone to errors, and the accuracy of the results needs to be confirmed by multiple sampling when there are abnormal data, which is not real-time and is prone to cause benzene containing impurities to enter the main reactor, thereby affecting the activity of the main reactor and causing the main reactor to be unable to operate continuously for a long period. SUMMARY

[0004] In order to overcome the problems in the prior art, the present application provides a method for promoting long-period continuous operation of an alkylation main reactor and application thereof, wherein an on-line replaceable pre-reactor is arranged before the alkylation main reactor, which not only removes the impurities in the benzene raw material but also has an indicating effect, can sensitively detect the deactivation state of the on-line pre-reactor, and replace the pre-reactor in time, which is simple and real-time, so that impurities cannot enter the alkylation main reactor, and the alkylation main reactor can be promoted to operate continuously for a long period, the frequency of replacing the main catalyst is reduced, the multi-stage raw material guard bed is saved, and the production efficiency of the device is improved.

[0005] In one aspect, the present application provides a method for long-period operation of a reactor, comprising: arranging an on-line replaceable pre-reactor before an alkylation main reactor along the material flow direction, introducing aromatic hydrocarbon raw material and olefin raw material into the pre-reactor, and introducing the outlet material of the pre-reactor into the alkylation main reactor and simultaneously independently introducing olefin raw material into the alkylation main reactor; wherein the pre-reactor is filled with a silicon-aluminum catalyst I, and the alkylation main reactor is filled with a silicon-aluminum catalyst II, and the silicon-aluminum ratio of the silicon-aluminum catalyst I is less than that of the silicon-aluminum catalyst II.

[0006] The pre-reactor has the function of protecting the bed and can indicate the operating status of the protective bed, ensuring the long-term normal operation of the main reactor.

[0007] The aromatic raw material is selected from at least one of benzene and toluene.

[0008] The olefin feedstock is selected from at least one of propylene, ethylene, butene, and long-chain olefins.

[0009] The silicon-aluminum catalyst II has a silicon-aluminum ratio ≥20.

[0010] The silicon-aluminum ratio of the silicon-aluminum catalyst I is less than or equal to 50% of the silicon-aluminum ratio of the silicon-aluminum catalyst II.

[0011] The olefin space velocity in the pre-reactor is controlled to be lower than that in the alkylation main reactor.

[0012] Preferably, the olefin space velocity in the pre-reactor is controlled to be less than 50% of the olefin space velocity in the alkylation main reactor.

[0013] More preferably, the olefin space velocity in the pre-reactor is 0.001–1.0 h⁻¹. -1 And / or, the olefin space velocity in the alkylation main reactor is 0.1–10 h⁻¹. -1 .

[0014] The molar ratio of the aromatic feedstock to the olefin feedstock in the alkylation main reactor is 100–2, preferably 30–2.

[0015] The temperature of the alkylation main reactor is controlled at 130–200 °C.

[0016] Preferably, the temperature of the pre-reactor is controlled to be lower than the temperature of the alkylation main reactor.

[0017] More preferably, the temperature difference between the pre-reactor and the alkylation main reactor is controlled to be ≥5°C.

[0018] The pressure of the pre-reactor and the alkylation main reactor is controlled independently at 0.1–10 MPa, preferably 0.2–3.5 MPa.

[0019] The online replaceable pre-reactor consists of two or more pre-reactors connected in parallel, of which only one is online and connected in series with the alkylation main reactor, while the others are in standby mode.

[0020] Preferably, the pre-reactor is replaced and regenerated when the temperature rise of the online pre-reactor decreases.

[0021] More preferably, the online pre-reactor is replaced and regenerated when the temperature rise drops to 1 / 4 to 1 / 2 of the initial operating temperature rise.

[0022] A second aspect of the invention is to provide the application of the method described in the first aspect of the invention, particularly in the alkylation reaction of aromatic hydrocarbons, for example in the preparation of cumene.

[0023] A third aspect of the present invention provides a method for alkylation of aromatic hydrocarbons, comprising: performing the alkylation of the aromatic hydrocarbons in an alkylation main reactor, and using the method described in the first aspect of the present invention to promote the long-term continuous operation of the alkylation main reactor.

[0024] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values; these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. In the following, various technical solutions can, in principle, be combined with each other to obtain new technical solutions, which should also be considered as specifically disclosed herein.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The pre-reactor is a protection reactor consisting of two or more parallel reactors, which can realize online switching and regeneration of the pre-reactor catalyst. The pre-reactor also has an indicator function, enabling the alkylation main reactor to operate continuously for a long period of time, reducing the frequency of main catalyst replacement, eliminating the need for multi-stage raw material protection beds, and improving the production efficiency of the unit.

[0027] (2) When applied to the preparation of cumene, the method still has the advantages of high olefin (e.g., propylene) conversion rate and low content of by-products (e.g., n-propylbenzene) in the product (e.g., cumene) after long-term continuous operation. Detailed Implementation

[0028] The features and advantages of the present invention will become clearer and more apparent from the following detailed description.

[0029] One objective of this invention is to provide a method for promoting long-term continuous operation of an alkylation main reactor, comprising: (along the material flow direction) setting up an online replaceable pre-reactor before the alkylation main reactor, introducing aromatic feedstock and olefin feedstock into the pre-reactor, the discharge of the pre-reactor entering the alkylation main reactor and simultaneously independently introducing olefin feedstock into the alkylation main reactor; wherein, the pre-reactor is filled with a silicon-aluminum catalyst I, and the alkylation main reactor is filled with a silicon-aluminum catalyst II, wherein the silicon-aluminum ratio of the silicon-aluminum catalyst I is lower than that of the silicon-aluminum catalyst II.

[0030] In a preferred embodiment, the aromatic raw material is selected from at least one of benzene and toluene; and / or, the olefin raw material is selected from at least one of propylene, ethylene, butene, and long-chain olefins, wherein the long-chain olefins refer to one or a mixture of several C8 to C18 olefins.

[0031] In a preferred embodiment, the silicon-to-aluminum ratio of the silicon-aluminum catalyst I is less than or equal to 50% of the silicon-to-aluminum ratio of the silicon-aluminum catalyst II.

[0032] For example, the silicon-to-aluminum ratio of the silicon-aluminum catalyst I is less than or equal to 50%, 45%, 40%, 30%, 20%, or 10% of the silicon-to-aluminum ratio of the silicon-aluminum catalyst II.

[0033] Alternatively, the silicon-aluminum ratio of the silicon-aluminum catalyst I is 5% to 50% of the silicon-aluminum ratio of the silicon-aluminum catalyst II, preferably 10% to 50%, for example, any point value or a range between any two values ​​from 50%, 45%, 40%, 30%, 20%, 10%, and 5%.

[0034] After extensive experimental research, the inventors discovered that using a catalyst with a low silicon-to-aluminum ratio as the pre-reactor catalyst has the characteristics of easy deactivation and poor stability. This may be a disadvantage in conventional alkylation reactions, but it is an advantage in this invention. This is because one of the functions of the pre-reactor is to act as an indicator. Thus, the pre-reactor of this invention, which uses a low silicon-to-aluminum ratio catalyst that is easy to deactivate and has poor stability, has the advantage of high sensitivity and can replace the pre-reactor in a timely manner.

[0035] In a further preferred embodiment, the silicon-aluminum catalyst II has a silicon-aluminum ratio ≥20, for example 20 to 100, more specifically any point value or any range of any two points among 20, 25, 30, 35, 40, 60, 80 or 100.

[0036] In a further preferred embodiment, the silica-alumina catalyst I is selected from at least one of Y zeolite and ZSM-5 zeolite; and / or, the silica-alumina catalyst II is selected from at least one of MWW zeolite and BETA zeolite.

[0037] In numerous experiments, the inventors discovered that when Y zeolite and ZSM-5 zeolite are used in the pre-reactor, they are more sensitive, and the deactivation of the pre-reactor can be detected more promptly. However, the inventors also found that if MWW zeolite is used for the silicon-aluminum catalyst I, the deactivation of the pre-reactor cannot be detected in a timely manner. In other words, after extensive experimental research, the inventors found that the sensitivity of MWW zeolite when used in the pre-reactor is not as good as that of Y zeolite and / or ZSM-5 zeolite.

[0038] In this invention, the silicon-aluminum catalyst I and silicon-aluminum catalyst II may optionally contain a binder, and there is no limitation on the content of the binder. For example, the content of the binder in silicon-aluminum catalyst I may be greater than, equal to or less than the content of the binder in silicon-aluminum catalyst II.

[0039] In a preferred embodiment, the olefin space velocity in the pre-reactor is controlled to be lower than the olefin space velocity in the alkylation main reactor.

[0040] In a further preferred embodiment, the olefin space velocity in the pre-reactor is controlled to be less than 50% of the olefin space velocity in the alkylation main reactor, for example, the olefin space velocity in the pre-reactor is controlled to be 5% to 50% of the olefin space velocity in the alkylation main reactor but not exceeding 50%.

[0041] For example, the propylene space velocity in the pre-reactor is controlled to be less than or equal to any point value or any range of any two points of the propylene space velocity in the alkylation main reactor, which are 45%, 40%, 30%, 20% or 10%.

[0042] In this invention, the pre-reactor serves two purposes: firstly, it removes impurities from the aromatic feedstock; secondly, a small amount of olefins is introduced into the pre-reactor for a small-scale alkylation reaction. This small-scale alkylation reactor acts as an indicator. Specifically, when the catalyst in the pre-reactor approaches deactivation due to the removal of impurities from the aromatic feedstock, the deactivation state can be detected or indicated promptly based on the temperature rise of the alkylation reaction within the pre-reactor. This allows for timely online replacement of the pre-reactor when it approaches deactivation, preventing the overuse of the catalyst and the resulting incomplete removal of impurities from the aromatic feedstock, which could then enter the main alkylation reactor and affect its long-term operation.

[0043] In a further preferred embodiment, the olefin space velocity in the pre-reactor is 0.001–1.0 h⁻¹. -1 For example, 0.001h -1 0.01h -1 0.1h -1 0.2h -1 0.4h -1 0.6h -1 0.8h -1 or 1.0h -1 Any point value or any range of any two point values ​​in the alkylation main reactor; and / or, the olefin space velocity in the alkylation main reactor is 0.1 to 10 h⁻¹. -1 For example, 0.1h -1 0.5h -1 1h -1 2h -1 4h -16h -1 8h -1 or 10h -1 Any point value or any range consisting of any two point values ​​in the range.

[0044] In a preferred embodiment, the molar ratio of the aromatic feedstock to the olefin feedstock in the alkylation main reactor is 100 to 2, preferably 30 to 2, for example, any point value or any two values ​​from 100, 90, 80, 70, 60, 50, 40, 30, 20, 10, 5 or 2.

[0045] In a preferred embodiment, the temperature of the pre-reactor is controlled to be lower than the temperature of the alkylation main reactor.

[0046] In a further preferred embodiment, the temperature difference between the pre-reactor and the alkylation main reactor is controlled to be ≥5°C, preferably 10 to 50°C, for example, any point value or any combination of two values ​​among 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, and 50°C.

[0047] In a further preferred embodiment, the temperature of the alkylation main reactor is controlled to be 130–200°C, for example, any point value or any combination of two values ​​among 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C or 200°C.

[0048] The pre-reactor mainly serves as an indicator. Through extensive experiments, the inventors discovered that when the pre-reactor is controlled at a temperature lower than that of the main reactor, the pre-reactor undergoes a slow reaction with low activity. The temperature rise detection of the pre-reactor is more sensitive and can detect the deactivation of the catalyst in the pre-reactor more promptly.

[0049] In a preferred embodiment, the pressure of the pre-reactor and the alkylation main reactor are each independently controlled to be 0.1 to 10 MPa, preferably 0.2 to 3.5 MPa, for example 0.2 MPa, 0.5 MPa, 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, 3 MPa or 3.5 MPa.

[0050] In a preferred embodiment, the online replaceable pre-reactor consists of two or more pre-reactors connected in parallel, of which only one is online and connected in series with the alkylation main reactor, while the others are in standby mode.

[0051] In a further preferred embodiment, the pre-reactor is replaced and regenerated when the temperature rise of the online pre-reactor decreases.

[0052] The operating status of the pre-reactor catalyst is reflected by the online temperature rise of the pre-reactor. During regeneration, a switching regeneration method is used, and the main reaction catalyst does not require regeneration and can operate stably.

[0053] In a further preferred embodiment, the pre-reactor is replaced and regenerated when the online temperature rise drops to 1 / 4 to 1 / 2 (e.g., one-third) of the initial operating temperature rise.

[0054] The regeneration method can be any regeneration method disclosed in the prior art, preferably but not limited to the method of hot benzene washing and / or charcoal burning regeneration.

[0055] In this invention, the pre-reactor not only removes impurities from the aromatic feedstock but also introduces a small amount of olefins into it for a slow reaction at a low temperature with a low-activity catalyst, allowing for sensitive monitoring of the catalyst deactivation level within the pre-reactor. This invention eliminates the need for continuous monitoring of the impurity content in the outlet feedstock; the determination can be made solely based on the temperature rise in the pre-reactor, making it simple and efficient.

[0056] A second objective of this invention is to provide an application of the method described in one objective of this invention in the alkylation reaction of aromatic hydrocarbons, such as its application in the preparation of cumene.

[0057] A third objective of this invention is to provide a method for alkylation of aromatic hydrocarbons (e.g., a method for preparing cumene), comprising: performing the alkylation of the aromatic hydrocarbons in an alkylation main reactor, and using a method of one objective of this invention to promote the long-term continuous operation of the alkylation main reactor.

[0058] Example

[0059] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0060] It should also be noted that the various specific technical features described in the following embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the various possible combinations will not be described separately in this invention.

[0061] Furthermore, various embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention. The resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0062] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0063] [Example 1] Preparation of cumene by alkylation

[0064] The system comprises a pre-reactor and an alkylation main reactor, wherein two pre-reactors are connected in parallel, one in operation and the other in standby mode. The pre-reactor is filled with Y zeolite at a silica-to-alumina ratio of 9; the main alkylation reactor is filled with Beta zeolite at a silica-to-alumina ratio of 30. Benzene and propylene are introduced into the pre-reactor, and the effluent from the pre-reactor enters the main alkylation reactor while propylene is independently introduced into the main alkylation reactor. The propylene weight hourly space velocity (WHSV) in the pre-reactor is 0.2 h⁻¹. -1 The propylene weight space velocity in the alkylation main reactor is 1.0 h⁻¹. -1 The molar ratio of benzene feedstock to propylene in the alkylation main reactor is 2.0; the temperature of the pre-reactor is controlled at 140℃, and the temperature of the alkylation main reactor is controlled at 155℃. The pressure of both the pre-reactor and the main reactor is controlled at 3.0 MPa.

[0065] When the temperature rise of the online pre-reactor is detected to be lower than one-third of the initial temperature rise, the pre-reactor is cut off for regeneration and switched to a standby pre-reactor. The alkylation main reactor does not need to be switched.

[0066] The reactor operated continuously for 150 days, with a propylene conversion rate greater than 99.99% and a cumene content of 220 ppm in the product cumene.

[0067]

Example 2

[0068] The system comprises a pre-reactor and an alkylation main reactor, wherein two pre-reactors are connected in parallel, one in operation and the other in standby mode. The pre-reactor is filled with ZSM-5 zeolite with a silica-to-alumina ratio of 15; the main alkylation reactor is filled with MCM-22 zeolite with a silica-to-alumina ratio of 30. Benzene and propylene are introduced into the pre-reactor, and the effluent from the pre-reactor enters the main alkylation reactor while propylene is independently introduced into the main alkylation reactor. The propylene weight hourly space velocity (WHSV) in the pre-reactor is 0.2 h⁻¹. -1 The propylene weight space velocity in the alkylation main reactor is 2.0 h⁻¹. -1 The molar ratio of benzene feedstock to propylene in the alkylation main reactor is 2.0; the temperature of the pre-reactor is controlled at 140℃, and the temperature of the alkylation main reactor is controlled at 155℃. The pressure of both the pre-reactor and the main reactor is controlled at 3.0 MPa.

[0069] When the temperature rise of the online pre-reactor is detected to be lower than one-third of the initial temperature rise, the pre-reactor is cut off for regeneration and switched to a standby pre-reactor. The alkylation main reactor does not need to be switched.

[0070] The reactor operated continuously for 150 days, with a propylene conversion rate of over 99.99% and a cumene content of 260 ppm in the product cumene.

[0071]

Example 3

[0072] The system comprises a pre-reactor and an alkylation main reactor, wherein two pre-reactors are connected in parallel, one in operation and the other in standby mode. The pre-reactor is filled with Y zeolite at a silica-to-alumina ratio of 5; the main alkylation reactor is filled with MCM-22 zeolite at a silica-to-alumina ratio of 25. Benzene feedstock and propylene are introduced into the pre-reactor, and the effluent from the pre-reactor enters the main alkylation reactor while propylene is independently introduced into the main alkylation reactor. The propylene weight hourly space velocity (WHSV) in the pre-reactor is 0.1 h⁻¹. -1 The propylene weight space velocity in the alkylation main reactor is 1.5 h⁻¹. -1 The molar ratio of benzene feedstock to propylene in the alkylation main reactor is 3.0; the temperature of the pre-reactor is controlled at 120℃, and the temperature of the alkylation main reactor is controlled at 160℃. The pressure of both the pre-reactor and the main reactor is controlled at 3.0 MPa.

[0073] When the temperature rise of the online pre-reactor is detected to be lower than one-third of the initial temperature rise, the pre-reactor is cut off for regeneration and switched to a standby pre-reactor. The alkylation main reactor does not need to be switched.

[0074] The reactor operated continuously for 150 days, with a propylene conversion rate of over 99.99% and a cumene content of 280 ppm in the product cumene.

[0075]

Example 4

[0076] The process employs a system comprising a pre-reactor and an alkylation main reactor. Two pre-reactors are connected in parallel, one online and the other in standby mode. The pre-reactor is filled with Y zeolite at a silica-to-alumina ratio of 9; the main alkylation reactor is filled with Beta zeolite at a silica-to-alumina ratio of 30. Benzene feedstock and n-butene are introduced into the pre-reactor, and the effluent from the pre-reactor enters the main alkylation reactor while n-butene is independently introduced into the main alkylation reactor. The butene weight hourly space velocity (WHSV) in the pre-reactor is 0.2 h⁻¹. -1 The butene weight space velocity in the alkylation main reactor was 0.6 h⁻¹. -1The molar ratio of benzene feedstock to n-butene in the alkylation main reactor is 2.0; the temperature of the pre-reactor is controlled at 140℃, and the temperature of the alkylation main reactor is controlled at 155℃. The pressure of both the pre-reactor and the main reactor is controlled at 3.0 MPa.

[0077] When the temperature rise of the online pre-reactor is detected to be lower than one-third of the initial temperature rise, the pre-reactor is cut off for regeneration and switched to a standby pre-reactor. The alkylation main reactor does not need to be switched.

[0078] The reactor operated continuously for 150 days, achieving a butene conversion rate of over 99.9% and a sec-butylbenzene selectivity of over 99%.

[0079]

Example 5

[0080] The system comprises a pre-reactor and an alkylation main reactor, wherein two pre-reactors are connected in parallel, one in operation and the other in standby mode. The pre-reactor is filled with Y zeolite at a silica-to-alumina ratio of 9; the main alkylation reactor is filled with Beta zeolite at a silica-to-alumina ratio of 30. Toluene and propylene are introduced into the pre-reactor, and the effluent from the pre-reactor enters the main alkylation reactor while propylene is independently introduced into the main alkylation reactor. The propylene weight hourly space velocity (WHSV) in the pre-reactor is 0.1 h⁻¹. -1 The propylene weight space velocity in the alkylation main reactor is 0.5 h⁻¹. -1 The molar ratio of toluene feedstock to propylene in the alkylation main reactor is 4.0; the temperature of the pre-reactor is controlled at 140℃, and the temperature of the alkylation main reactor is controlled at 165℃. The pressure of both the pre-reactor and the main reactor is controlled at 3.0 MPa.

[0081] When the temperature rise of the online pre-reactor is detected to be lower than one-third of the initial temperature rise, the pre-reactor is cut off for regeneration and switched to a standby pre-reactor. The alkylation main reactor does not need to be switched.

[0082] The reactor operated continuously for 150 days, achieving a propylene conversion rate of over 99.85%.

[0083]

Example 6

[0084] The system comprises a pre-reactor and an alkylation main reactor, wherein two pre-reactors are connected in parallel, one in operation and the other in standby mode. The pre-reactor is filled with Y zeolite at a silica-to-alumina ratio of 5; the main alkylation reactor is filled with MCM-22 zeolite at a silica-to-alumina ratio of 25. Benzene feedstock and long-chain olefins (C12) are introduced into the pre-reactor, and the effluent from the pre-reactor enters the main alkylation reactor while long-chain olefins (C12) are independently introduced into the main alkylation reactor. The weight hourly space velocity (WHSV) of the long-chain olefins (C12) in the pre-reactor is 0.05 h⁻¹. -1 The weight space velocity (WHSV) of long-chain olefins in the alkylation main reactor is 0.2 h⁻¹. -1 The molar ratio of benzene feedstock to long-chain olefins (C12) in the alkylation main reactor is 10.0; the temperature of the pre-reactor is controlled at 150℃, and the temperature of the alkylation main reactor is controlled at 180℃. The pressure of both the pre-reactor and the main reactor is controlled at 3.0 MPa.

[0085] When the temperature rise of the online pre-reactor is detected to be lower than one-third of the initial temperature rise, the pre-reactor is cut off for regeneration and switched to a standby pre-reactor. The alkylation main reactor does not need to be switched.

[0086] The reactor operated continuously for 150 days, achieving a long-chain olefin (C12) conversion rate of over 99.99%.

[0087]

Example 7

[0088] The process employs a system comprising a pre-reactor and an alkylation main reactor. Two pre-reactors are connected in parallel, one online and the other in standby mode. The pre-reactor is packed with Y zeolite at a silica-to-alumina ratio of 5; the main alkylation reactor is packed with MCM-22 zeolite at a silica-to-alumina ratio of 20. Benzene feedstock and long-chain C14 olefins are introduced into the pre-reactor. The effluent from the pre-reactor enters the main alkylation reactor, while long-chain olefins (C14) are simultaneously and independently introduced into the main alkylation reactor. The weight hourly space velocity (WHSV) of the long-chain olefins (C14) in the pre-reactor is 0.1 h⁻¹. -1 The weight space velocity (WHSV) of long-chain olefins in the alkylation main reactor is 0.2 h⁻¹. -1 The molar ratio of benzene feedstock to long-chain C14 olefins in the alkylation main reactor is 20.0; the temperature of the pre-reactor is controlled at 130℃, and the temperature of the alkylation main reactor is controlled at 170℃. The pressure of both the pre-reactor and the main reactor is controlled at 3.0 MPa.

[0089] When the temperature rise of the online pre-reactor is detected to be lower than one-third of the initial temperature rise, the pre-reactor is cut off for regeneration and switched to a standby pre-reactor. The alkylation main reactor does not need to be switched.

[0090] The reactor operated continuously for 150 days, achieving a long-chain olefin (C14) conversion rate of over 99.99%.

[0091]

Example 8

[0092] The process employs a system comprising a pre-reactor and an alkylation main reactor. Two pre-reactors are connected in parallel, one online and the other in standby mode. The pre-reactor is filled with Y zeolite at a silica-to-alumina ratio of 9; the main alkylation reactor is filled with Beta zeolite at a silica-to-alumina ratio of 30. Benzene feedstock and long-chain olefins (C16) are introduced into the pre-reactor. The effluent from the pre-reactor enters the main alkylation reactor, while long-chain olefins (C16) are simultaneously introduced independently into the main alkylation reactor. The weight hourly space velocity (WHSV) of the long-chain olefins (C16) in the pre-reactor is 0.1 h⁻¹. -1 The weight space velocity (WHSV) of long-chain olefins (C16) in the alkylation main reactor was 0.3 h⁻¹. -1 The molar ratio of benzene feedstock to long-chain olefins (C16) in the alkylation main reactor is 30.0; the temperature of the pre-reactor is controlled at 140℃, and the temperature of the alkylation main reactor is controlled at 195℃. The pressure of both the pre-reactor and the main reactor is controlled at 3.0 MPa.

[0093] When the temperature rise of the online pre-reactor is detected to be lower than one-third of the initial temperature rise, the pre-reactor is cut off for regeneration and switched to a standby pre-reactor. The alkylation main reactor does not need to be switched.

[0094] The reactor operated continuously for 150 days, achieving a long-chain olefin (C16) conversion rate of over 99.99%.

[0095] Comparative Example 1

[0096] The process of Example 1 was repeated, except that the pre-reactor was filled with Beta zeolite, and other conditions remained the same.

[0097] After the reactor operated continuously for 150 days, the propylene conversion rate decreased to 99.45%, and the n-propylbenzene content in the product cumene was 410 ppm.

[0098] Comparative Example 2

[0099] The process of Example 1 was repeated, except that the temperature of the pre-reactor was the same as that of the alkylation main reactor, which was 155°C, and other conditions remained unchanged.

[0100] The reactor operated continuously for 150 days, achieving a propylene conversion rate greater than 99.99%, with the product cumene containing 590 ppm of n-propylbenzene. The pre-reactor, operating at a higher temperature, exhibited a higher content of the impurity n-propylbenzene.

[0101] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A method for promoting long-term continuous operation of an alkylation main reactor, comprising: An online replaceable pre-reactor is installed before the alkylation main reactor along the material flow direction. Aromatic and olefin feedstocks are introduced into the pre-reactor. The discharge from the pre-reactor enters the alkylation main reactor, and olefin feedstock is simultaneously introduced into the alkylation main reactor independently. The pre-reactor is filled with silicon-aluminum catalyst I, and the alkylation main reactor is filled with silicon-aluminum catalyst II. The silicon-aluminum ratio of silicon-aluminum catalyst I is lower than that of silicon-aluminum catalyst II. Silicon-aluminum catalyst I is easily deactivated, has poor stability, and is highly sensitive. The pre-reactor is replaced and regenerated when the temperature rise decreases.

2. The method according to claim 1, characterized in that, The aromatic raw material is selected from at least one of benzene and toluene; and / or, the olefin raw material is selected from at least one of propylene, ethylene, butene, and long-chain olefins.

3. The method according to claim 1, characterized in that, The silicon-aluminum catalyst II has a silicon-aluminum ratio ≥20.

4. The method according to claim 1, characterized in that, The silicon-aluminum ratio of the silicon-aluminum catalyst I is less than or equal to 50% of the silicon-aluminum ratio of the silicon-aluminum catalyst II.

5. The method according to claim 1, characterized in that, The olefin space velocity in the pre-reactor is controlled to be lower than that in the alkylation main reactor.

6. The method according to claim 1, characterized in that, The olefin space velocity in the pre-reactor is controlled to be less than 50% of the olefin space velocity in the alkylation main reactor.

7. The method according to claim 1, characterized in that, The olefin space velocity in the pre-reactor is 0.001~1.0 h⁻¹. -1 And / or, the olefin space velocity in the alkylation main reactor is 0.1~10 h⁻¹. -1 .

8. The method according to claim 1, characterized in that, The molar ratio of the aromatic feedstock to the olefin feedstock in the alkylation main reactor is 100-2.

9. The method according to claim 1, characterized in that, The molar ratio of the aromatic feedstock to the olefin feedstock in the alkylation main reactor is 30-2.

10. The method according to claim 1, characterized in that, The temperature of the alkylation main reactor is controlled at 130~200℃.

11. The method according to claim 1, characterized in that, The temperature of the pre-reactor is controlled to be lower than the temperature of the alkylation main reactor.

12. The method according to claim 1, characterized in that, The pressures of the pre-reactor and the alkylation main reactor are controlled independently at 0.1~10 MPa.

13. The method according to claim 1, characterized in that, The pressures of the pre-reactor and the alkylation main reactor are each controlled independently at 0.2–3.5 MPa.

14. The method according to any one of claims 1 to 13, characterized in that, The online replaceable pre-reactor consists of two or more pre-reactors connected in parallel, of which only one is online and connected in series with the alkylation main reactor, while the others are in standby mode.

15. The method according to claim 14, characterized in that, When the temperature rise of the online pre-reactor drops to 1 / 4 to 1 / 2 of the initial operating temperature rise, it should be replaced and regenerated.

16. The application of the method according to any one of claims 1 to 15, in the alkylation reaction of aromatic hydrocarbons.

17. The application of the method according to claim 16 in the preparation of cumene.

18. A method for alkylating aromatic hydrocarbons, comprising: The aromatic hydrocarbon alkylation is carried out in the alkylation main reactor, and the long-term continuous operation of the alkylation main reactor is promoted by the method described in any one of claims 1 to 15.