Method and system for preparing alkylene oxides

Abstract

The present invention discloses a method and system for preparing alkylene oxide, which comprises the steps of supplying a feed containing an olefin, an alkylbenzene hydroperoxide, and an alkylbenzene to a reaction zone containing at least two catalyst beds connected in series to carry out an epoxidation reaction and obtain a reaction product containing an alkylene oxide, wherein when a logical first-stage catalyst bed is deactivated, the catalyst bed is cut out and a new or regenerated catalyst bed is cut in, and the inlet temperature of the feed entering the cut-out new or regenerated catalyst bed satisfies the following formula (1) so that the temperature of the effluent leaving the cut-out new or regenerated catalyst bed is 130°C or less: [Equation 1] JPEG2025536408000141.jpg12169 The system is used to prepare alkylene oxide and is equipped with a temperature control device that controls the inlet temperature of the feed to a newly inserted fresh catalyst bed or a regenerated catalyst bed so that equation (1) is satisfied.

Description

Detailed Description of the Invention

[0001] [Technical Field] The present invention is in the field of epoxidation reactions, and more particularly relates to an epoxidation process and a system for carrying out epoxidation.

[0002] [Background technology] Like oxidation reactions, epoxidation reactions are also highly exothermic. For example, the liquid-phase catalytic reaction of preparing propylene oxide from cumene hydroperoxide (CHP) and propylene is highly exothermic. In highly exothermic reactions, if the reactants and / or products are highly temperature-sensitive (i.e., heat-sensitive materials), additional heat removal or temperature control schemes are required to maintain the reactor within a reasonable reaction temperature range. Inadequate temperature control of the reaction system can result in reduced selectivity of the reaction product and, in severe cases, reaction temperature runaway, leading to safety hazards.

[0003] The effect of reactor inlet temperature on peroxide conversion in an adiabatic fixed-bed epoxidation reactor is disclosed, for example, in Patent CN1692106A. In an adiabatic fixed-bed reactor, the peroxide conversion can only be stably controlled to less than 20% under normal conditions to prevent temperature runaway. Patent CN1692106A discloses a method for conducting a highly exothermic reaction by connecting multiple independent reaction zones in series, feeding propylene in one stage and organic peroxide in multiple parallel stages, thereby keeping the peroxide concentration in the feed in each reaction zone below 8% by mass and stabilizing the reaction temperature. Patent document CN105294606A discloses a reaction method for preparing propylene oxide from ethylbenzene hydroperoxide and propylene. The reaction system comprises at least two adiabatic fixed-bed catalytic reactors connected in series. Propylene and a feed containing ethylbenzene hydroperoxide are mixed and passed through a first-stage reactor. The concentration of ethylbenzene hydroperoxide at the inlet of the second-stage reactor and the temperature of the inlet feed are adjusted by circulating the feed from the outlet of the second-stage reactor. Patent document CN110787739A discloses an apparatus and method for producing alkylene oxide by reacting alkylbenzene peroxide with low-carbon olefins. The reaction system comprises an isothermal bed reactor and an optional adiabatic bed reactor, and the isothermal bed reactor is equipped with heat exchange inlet and outlet pipelines for controlling the reaction temperature rise. Because the epoxidation reaction is highly exothermic, the heat removal capacity of the isothermal bed reactor is limited by heat transfer, so the isothermal bed reactor will form a large temperature gradient in the axial and radial directions of the reactor, which may cause part of the catalyst to reach a high temperature state and lead to serious side reactions.

[0004] Because organic peroxides are easily decomposed by heat, complete conversion of the organic peroxides in the epoxidation reaction zone is important and necessary to ensure the safety and economy of the subsequent product separation process. Patent CN1325484C discloses an epoxidation reaction system using a fixed-bed reactor equipped with a solid epoxidation catalyst. This system uses multiple fixed-bed reactors connected in series with fresh and partially deactivated catalysts, where olefins are sequentially fed to the reactors equipped with the fresh catalyst, and organic peroxides are fed in parallel to the reactors equipped with the fresh catalyst. The effluent from the reactor equipped with the fresh catalyst must be passed through at least one fixed-bed reactor equipped with a partially deactivated catalyst to ensure complete conversion of the organic peroxides. Patent CN105272947A discloses a method for continuously producing epichlorohydrin, in which a plurality of reactors connected in series are arranged in a reaction zone, propylene enters the reactors sequentially, and organic peroxide enters each reactor in parallel, and the temperature of the last reactor must be higher than the temperature of any other reactor, thereby ensuring that the conversion rate of the organic peroxide in the last reactor is 100%.

[0005] Because epoxidation catalysts are quickly deactivated, the deactivated catalyst must be repeatedly removed from the reaction system and replaced with a new catalyst. After the new catalyst is replaced, when the epoxidation reactor is re-introduced into the system, the organic hydrocarbon hydroperoxides entering the reactor can be completely converted due to the high activity of the new catalyst. If the inlet temperature of the epoxidation reactor is too high, the temperature rise of the epoxidation reactor will exceed the normal control value, increasing side reactions and significantly reducing product selectivity.

[0006] [Details of the invention] To overcome at least one of the above-mentioned problems existing in the prior art, the present invention provides an epoxidation process (i.e., a process for preparing alkylene oxide), a method for controlling the temperature of an effluent from a newly introduced or regenerated catalyst bed in the process for preparing alkylene oxide, and a system for preparing alkylene oxide. The method and system can control the inlet temperature of the feed to the newly introduced catalyst bed based on parameters such as the temperature rise of the catalyst bed and the molar ratio between components in the feedstock, thereby controlling the temperature of the effluent from the newly introduced catalyst bed. The system and method can prevent the reaction from becoming uncontrollable due to the heat of reaction and can improve the conversion of the reactant cumene hydroperoxide and the selectivity to the target alkylene oxide, such as propylene oxide.

[0007] The present inventors have surprisingly found through numerous experiments that in the process for preparing alkylene oxide of the present invention, when the reaction temperature is higher than 130° C., the selectivity to the target alkylene oxide significantly decreases and the impurity content in the outlet product significantly increases. Therefore, one object of the present invention is to provide a process for preparing alkylene oxide (epoxidation process) in which the outlet temperature of a newly inserted new catalyst bed or a regenerated catalyst bed can be controlled to 130° C. or less.

[0008] One aspect of the present invention is a method for preparing alkylene oxide, comprising the step of supplying a feed containing an olefin, an alkylbenzene hydroperoxide, and an alkylbenzene to an epoxidation reaction zone comprising at least two catalyst beds connected in series to carry out an epoxidation reaction and obtain a reaction product containing an alkylene oxide, wherein the feed enters the logical first-stage catalyst bed (logically the first-stage catalyst bed, logically the first catalyst bed) of the at least two catalyst beds connected in series and passes sequentially through the at least two catalyst beds connected in series, and when a catalyst bed is deactivated, for example, when the logical first-stage catalyst bed is deactivated, the deactivated catalyst bed is cut out and a new catalyst bed or a regenerated catalyst bed is cut in.

[0009] The inlet temperature of the feed entering the inserted fresh or regenerated catalyst bed satisfies the following formula (1) so that the temperature of the effluent leaving the inserted fresh or regenerated catalyst bed is 130°C or less.

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[0010] In formula (1),

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[0011] Another aspect of the present invention is a method for preparing alkylene oxide, comprising the steps of: supplying a feed containing an olefin, an alkylbenzene hydroperoxide, and an alkylbenzene to an epoxidation reaction zone comprising at least two catalyst beds connected in series to carry out an epoxidation reaction and obtain a reaction product containing alkylene oxide; the feed enters a logical first-stage catalyst bed among the at least two catalyst beds connected in series and passes sequentially through the at least two catalyst beds connected in series; when the logical first-stage catalyst bed is deactivated, the first-stage catalyst bed is cut out and a new or regenerated catalyst bed is cut in; and the method further comprises controlling the inlet temperature of the feed entering the cut-out new or regenerated catalyst bed to satisfy the following formula (1):

[0012]

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[0013] As will be appreciated by those skilled in the art, in a process for preparing alkylene oxide from an olefin and an alkylbenzene hydroperoxide, the catalyst deactivation rate in the logically first catalyst bed (i.e., the first catalyst bed) of a series of connected catalyst beds is faster than the catalyst deactivation rate in the other catalyst beds due to the high content of alkylbenzene hydroperoxide entering this catalyst bed. After the catalyst deactivates, it is necessary to switch the deactivated catalyst bed out of the system and replace it with a new or regenerated catalyst bed.

[0014] When a new or regenerated catalyst bed is switched on, the alkylbenzene hydroperoxide entering this catalyst bed is completely converted due to the high activity of the new or regenerated catalyst. However, if the inlet temperature of the feed entering this new or regenerated catalyst bed is too high, the temperature of the new or regenerated catalyst bed will rise beyond the normal control value, resulting in an increase in side reactions and a significant decrease in product selectivity.

[0015] It has surprisingly been found by the present application that the inlet temperature of the feed entering a newly inserted new catalyst bed or a regenerated catalyst bed can be controlled so as to satisfy the following formula (1):

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[0016] Preferably, the inlet temperature of the feed entering the newly inserted new catalyst bed or the regenerated catalyst bed is controlled so as to satisfy the following formula (1a):

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[0017] The temperature of the effluent discharged from the newly inserted fresh catalyst bed or the regenerated catalyst bed can be effectively controlled to be 130° C. or less. In the formulas (1), (1a), (1b), (1c) and (2),

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[0018] In Equation (1), Equation (1a), Equation (1b), Equation (1c), and Equation (2), N represents the stage of a newly inserted fresh or regenerated catalyst bed in all the serially connected catalyst beds in the epoxidation reaction zone. That is, after a fresh or regenerated catalyst bed is inserted in the epoxidation reaction zone, all the serially connected catalyst beds in the epoxidation reaction zone are numbered 1, 2, ..., N-1, N, N+1, ... according to their logical stages (i.e., their order in the serial connection). The newly inserted fresh or regenerated catalyst bed is numbered N (i.e., the Nth bed in the series of serially connected catalyst beds). It should be noted that the above numbering order of "1, 2, ..., N-1, N, N+1, ..." is merely exemplary, and in practice, N can be 1 (i.e., the first bed in the series of serially connected catalyst beds (the logical first stage bed)), 2 (i.e., the second stage bed in the series of serially connected catalyst beds), 3, 4, 5, 6, etc. Alternatively, the total number of all catalyst beds connected in series in the epoxidation reaction zone can be N, i.e., the newly inserted fresh catalyst bed or regenerated catalyst bed is the last bed (i.e., the logically last bed).

[0019] In formula (1), formula (1a), formula (1b), formula (1c) and formula (2),

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[0020] In formula (1), formula (1a), formula (1b), formula (1c) and formula (2),

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[0021] In equations (1), (1a), (1b), (1c), and (2), a1 represents the molar ratio of olefin to alkylbenzene hydroperoxide in the feed, and b1 represents the molar ratio of alkylbenzene to alkylbenzene hydroperoxide in the feed. Note that a1 represents the molar ratio of olefin to alkylbenzene hydroperoxide in the feed entering a logical first-stage catalyst bed (i.e., the first bed) in a series-connected series of catalyst beds, and b1 represents the molar ratio of alkylbenzene to alkylbenzene hydroperoxide in the feed entering a logical first-stage catalyst bed (i.e., the first bed) in a series-connected series of catalyst beds.

[0022] In the present application, when a plurality of olefins or a plurality of alkylbenzenes are used, the molar ratio is calculated using the total molar amount of the plurality of olefins or the total molar amount of the plurality of alkylbenzenes.

[0023] In the present invention, the range of the inlet temperature of the feed to the inserted new catalyst bed or regenerated catalyst bed can be obtained by formula (1), formula (1a), formula (1b), formula (1c), or formula (2). The inlet temperature of the feed to the new catalyst bed or regenerated catalyst bed can be arbitrarily selected within the range of the inlet temperature obtained by formula (1), formula (1a), formula (1b), formula (1c), or formula (2). For example,

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[0024] In some embodiments, the α-value is calculated according to formula (1), formula (1a), formula (1b), formula (1c), or formula (2):

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[0025] In some embodiments, the outlet temperature of the previous bed immediately upstream of the newly inserted fresh or regenerated catalyst bed is calculated according to Equation (1), Equation (1a), Equation (1b), Equation (1c), or Equation (2).

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[0026] In some embodiments, the outlet temperature of the pre-bed immediately upstream of the newly inserted fresh or regenerated catalyst bed is calculated according to Equation (1), Equation (1a), Equation (1b), Equation (1c), or Equation (2).

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[0027] In some embodiments, the outlet temperature of the previous bed immediately upstream of the newly inserted fresh or regenerated catalyst bed is calculated according to Equation (1), Equation (1a), Equation (1b), Equation (1c), or Equation (2).

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[0028] In the present invention, the inlet temperature of the newly introduced new catalyst bed or regenerated catalyst bed can be precisely controlled by using Equation (1), Equation (1a), Equation (1b), Equation (1c), or Equation (2), so that the bed outlet temperature can be controlled to 130°C or less, and unnecessary energy consumption can be avoided. Specifically, there is no need to significantly lower the inlet temperature of the new catalyst bed, otherwise serious energy waste may occur. For example, in the case of a newly introduced reactor R i If it is calculated that the inlet temperature of needs to be controlled between 40 and 100°C, R i The outlet temperature of the upstream reactor (catalyst bed) is about 120 to 130°C, so R i The closer the inlet temperature is to the calculated upper limit of 100°C, the less cooling is required, resulting in energy savings.

[0029] In some embodiments of the process of the present invention, the newly inserted fresh or regenerated catalyst bed can be located at any stage in the series of catalyst beds connected in the epoxidation reaction zone, for example, at the logical first stage, the logical last stage, or any stage therebetween. However, preferably, in some embodiments of the present invention, the newly inserted fresh or regenerated catalyst bed is located at the logical Nth stage (i.e., the Nth bed) in the series of catalyst beds, and the sum of the temperature rises of the N-1 catalyst beds upstream of the newly inserted fresh or regenerated catalyst bed satisfies the following equation (3):

[0030]

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[0031] In some embodiments, the newly inserted fresh or regenerated catalyst bed may be located at the logical end of the series-connected catalyst beds in the epoxidation reaction zone.

[0032] In some embodiments, the alkylene oxide may be selected from the group consisting of propylene oxide, ethylene oxide, and butylene oxide, preferably propylene oxide. In some embodiments, the olefin may be selected from the group consisting of ethylene, propylene, and butene, more preferably propylene.

[0033] In some embodiments, the alkylbenzene hydroperoxide is cumene hydroperoxide. In some embodiments, the alkylbenzene can be at least one selected from ethylbenzene, cumene, butylbenzene, or a combination thereof, preferably cumene.

[0034] In a preferred embodiment, the olefin is propylene and the alkylbenzene hydroperoxide is cumene hydroperoxide. In a preferred embodiment, the olefin is propylene, the alkylbenzene hydroperoxide is cumene hydroperoxide, and the alkylbenzene is cumene.

[0035] In the process of the present invention, an olefin such as propylene can be provided as a propylene stream. In some embodiments, the alkylbenzene hydroperoxide is provided in the form of a solution, the solution comprising alkylbenzene hydroperoxide and an alkylbenzene, the alkylbenzene being a solvent or dispersant. In some embodiments, the alkylbenzene can be at least one selected from ethylbenzene, cumene, butylbenzene, and combinations thereof, preferably cumene.

[0036] The method of the present invention does not have any particular requirements regarding the concentration of the solution containing alkylbenzene hydroperoxide and alkylbenzene. In some embodiments, the concentration of alkylbenzene in the solution may be 5% by mass to 95% by mass, preferably 40% by mass to 90% by mass, for example, 40%, 50%, 60%, 70%, 80%, or 90% by mass.

[0037] In the method of the present invention, there are no particular requirements for the molar ratio a1 of olefin to alkylbenzene hydroperoxide in the feed, as long as alkylene oxide can be prepared. In some embodiments, the molar ratio of olefin to alkylbenzene hydroperoxide can be 2 to 50, preferably 2 to 12. For example, the molar ratio of olefin to alkylbenzene hydroperoxide can be 2, 4, 6, 8, 10, 12, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, or a range formed by any two of the above values.

[0038] In the method of the present invention, there are no particular requirements for the molar ratio b1 of alkylbenzene to alkylbenzene hydroperoxide in the feed, as long as alkylene oxide can be prepared. In some embodiments, the molar ratio b1 of alkylbenzene to alkylbenzene hydroperoxide in the feed can be 1 to 30, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, or a range formed by any two of the above values.

[0039] In some embodiments, the propylene may be preheated before being fed. Various heating means commonly known in the art may be used for preheating. For example, preheating means include, but are not limited to, electrical heating, steam heating, hot water heating, and heat exchange. In some embodiments, the propylene may be preheated to a temperature of 0 to 130°C, such as 0°C, 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, or a range formed by any two of the above values.

[0040] In the process of the present invention, in some embodiments, propylene and the solution containing alkylbenzene hydroperoxide and alkylbenzene can be fed separately to the logical first catalyst bed, or propylene and the solution containing alkylbenzene hydroperoxide and alkylbenzene can be first mixed to obtain a mixture that is then fed to the logical first catalyst bed. In some embodiments, preferably, propylene and the solution containing alkylbenzene hydroperoxide and alkylbenzene are first mixed and then fed to the catalyst bed.

[0041] In the process of the present invention, the effluent from each catalyst bed is sent to the inlet of the next catalyst bed. In the process of the present invention, if necessary, the effluent from each catalyst bed can be cooled to achieve the desired temperature (i.e., the inlet temperature of the next catalyst bed). In some embodiments of the process of the present invention, propylene can be preheated to the inlet temperature of the theoretical first stage catalyst bed, and the effluent from each catalyst bed is cooled to the inlet temperature of the next bed.

[0042] To cool the catalyst bed effluent, the present invention can employ any cooling means commonly known in the art. In some embodiments, cooling can include, but is not limited to, air cooling, water cooling, or heat integration.

[0043] Methods for preparing alkylene oxide by reacting an olefin with an alkylbenzene hydroperoxide in a solution in the presence of a catalyst are known to those skilled in the art. Those skilled in the art can suitably select the inlet temperature of each catalyst bed, provided that the outlet temperature of each catalyst bed does not exceed 130°C. In some embodiments, the inlet temperature of each catalyst bed can be in the range of 0 to 130°C. In the method of the present invention, those skilled in the art can suitably select the pressure of each catalyst bed, for example, the pressure of each catalyst bed can be in the range of 2 to 20 MPa.

[0044] In some embodiments, the inlet temperature of each catalyst bed can be in the range of 40 to 130° C., the outlet temperature of each catalyst bed does not exceed 130° C., and the pressure of each catalyst bed can be in the range of 3 to 12 MPa g. For example, the inlet temperature of each catalyst bed can be 40° C., 50° C., 60° C., 70° C., 80° C., 90° C., 100° C., 110° C., 120° C., or 130° C., or a range formed by any two of the above values, and / or the pressure of each catalyst bed can be 3 MPa g, 4 MPa g, 5 MPa g, 6 MPa g, 7 MPa g, 8 MPa g, 9 MPa g, 10 MPa g, 11 MPa g, or 12 MPa g, or a range formed by any two of the above values.

[0045] In the method of the present invention, the epoxidation reaction temperature can be 0 to 200°C and the pressure can be 2 to 20MPag, and preferably the epoxidation reaction temperature can be 40 to 130°C and the pressure can be 3 to 12MPag.

[0046] For the process of the present invention, in some embodiments, the catalyst bed inlet temperature and catalyst bed pressure are such that the epoxidation reaction carried out in the catalyst bed is a properly liquid phase reaction.

[0047] As is known in the art, the epoxidation reaction of the present invention is highly exothermic. Therefore, the inlet temperature of the catalyst bed

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[0048] In some embodiments of the present invention, the catalyst bed (reactor) does not have a temperature rise, i.e., the inlet temperature

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[0049] In some embodiments, the epoxidation reaction zone can contain 2 to 20, preferably 3 to 20, preferably 3 to 10, more preferably 3 to 7, e.g., 3 to 6, catalyst beds connected in series. In yet some other embodiments, the epoxidation reaction zone can contain 2 to 10, preferably 2 to 5, catalyst beds connected in series. For example, the epoxidation reaction zone can contain 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 catalyst beds connected in series. The catalyst beds in the epoxidation reaction zone are each replenished with an epoxidation catalyst. Each catalyst bed in the epoxidation reaction zone can be replenished with the same amount of epoxidation catalyst or with a different amount of epoxidation catalyst.

[0050] The epoxidation catalyst can be any catalyst known in the art that can catalyze an epoxidation reaction. Preferably, the epoxidation catalyst is a titanium-containing catalyst, more preferably at least one selected from titanium silicon molecular sieves, titanium dioxide, and combinations thereof.

[0051] In some embodiments of the present invention, the catalyst used in the epoxidation reaction of the present invention can be the catalyst disclosed in CN104437618B. In some embodiments of the present invention, the catalyst bed of the present invention can comprise particles of an epoxidation catalyst. The catalyst particles can have any particle shape and size commonly known or used in the art.

[0052] The catalyst bed of the present invention can have any bed height and any bed shape. In some embodiments of the present invention, the catalyst bed of the present invention can have any bed height and bed shape commonly known or used in the art. In some embodiments, the catalyst bed of the present invention can be a fixed-bed catalyst bed.

[0053] In the present invention, the reactants can flow from top to bottom through the catalyst bed or from bottom to top through the catalyst bed, preferably from bottom to top through the catalyst bed.

[0054] For example, the stream enters the top of the catalyst bed, flows through the catalyst bed, and exits the bottom of the catalyst bed. In the process of the present invention, a feed comprising olefin, alkylbenzene hydroperoxide, and alkylbenzene is provided at a catalyst bed located in the logical first stage of the reaction zone.

[0055] In the process of the present invention, the reaction product (effluent) of the logically preceding catalyst bed enters the logically succeeding catalyst bed as a feed for the logically succeeding catalyst bed. In some embodiments, the mass hourly space velocity of alkylbenzene hydroperoxide is 0.1 to 3 h , based on the total amount of catalyst present in the epoxidation reaction zone. -1 , preferably 0.2 to 2 hours-1 , e.g., 0.2h -1 , 0.3h -1 , 0.4h -1 , 0.5h -1 , 0.6h -1 , 0.7h -1 , 0.8h -1 , 0.9h -1 , 1h -1 , 1.1h -1 , 1.2h -1 , 1.3h -1 , 1.4h -1 , 1.5h -1 , 1.6h -1 , 1.7h -1 , 1.8h -1 , 1.9h -1 or 2h -1 is.

[0056] In the method of the present invention, a "fresh catalyst bed" refers to a layer containing a new catalyst, and a "fresh catalyst" refers to a new, unused catalyst. In the method of the present invention, a "regenerated catalyst bed" refers to a catalyst bed whose catalytic performance has been regenerated, and is obtained by a catalyst regeneration treatment after the catalyst bed has been deactivated. Various catalyst regeneration methods known in the art can be used to regenerate a deactivated catalyst. In the present invention, the term "catalyst bed" can be used interchangeably with the term "reactor." That is, in the present invention, one catalyst bed is configured as one reactor.

[0057] Another aspect of the present invention is a system for preparing alkylene oxide, comprising an epoxidation reaction zone including at least two catalyst beds connected in series, and a temperature control device, wherein a feed containing an olefin, an alkylbenzene hydroperoxide, and an alkylbenzene enters the epoxidation reaction zone and performs an epoxidation reaction to obtain a product containing alkylene oxide, the feed enters the logical first-stage catalyst bed of the at least two catalyst beds connected in series, and passes sequentially through the at least two catalyst beds connected in series, and the temperature control device controls the inlet temperature of the feed to the newly inserted new catalyst bed or the regenerated catalyst bed so that the inlet temperature satisfies the following formula (1):

[0058]

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[0059] In some embodiments, in the inventive system, the alkylene oxide, the catalyst bed of the epoxidation reaction zone, the catalyst of the catalyst bed, the olefin, the alkylbenzene hydroperoxide and alkylbenzene, the epoxidation reaction, and equation (1) can be as described above for the inventive process.

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[0060] In some embodiments, the logical first stage catalyst bed is preceded by an olefin feed pipeline and an alkylbenzene hydroperoxide feed pipeline connected to the logical first stage catalyst bed.

[0061] In some embodiments, a preheating element is located on the olefin supply pipeline, preferably the preheating element is a heater or a heat exchanger.

[0062] In some embodiments, the cooling element is disposed on the connecting pipeline between two adjacent catalyst beds. In some embodiments, the cooling element can be an air-cooled element, a water-cooled element, or a heat integration element.

[0063] In some embodiments, the epoxidation reaction zone can contain from 2 to 20, preferably from 3 to 20, preferably from 3 to 10, preferably from 3 to 7, preferably from 3 to 6, catalyst beds connected in series. For example, the epoxidation reaction zone can contain 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 catalyst beds connected in series.

[0064] In some embodiments, the epoxidation reaction zone can contain 2 to 10, preferably 2 to 5, catalyst beds connected in series. In some embodiments, the newly switched-on fresh or regenerated catalyst bed is located at the logical last stage of the epoxidation reaction zone. In some embodiments, the inlet and outlet of each catalyst bed are each independently equipped with a switch valve for switching the catalyst bed on or off.

[0065] For example, a catalyst bed in the logical first stage of the epoxidation reaction zone may be cut out after deactivation, and a fresh or regenerated catalyst bed may be cut into the epoxidation reaction zone, e.g., in the logical last stage of the epoxidation reaction zone.

[0066] In some embodiments, the system further comprises one or more fresh or regenerated catalyst beds to be cut in. In some embodiments, logical stage catalyst beds in the epoxidation reaction zone may be cut out based on the logical stage after deactivation, and a fresh or regenerated catalyst bed may be cut into the epoxidation reaction zone after the deactivated catalyst bed is cut out, e.g., the logical last stage epoxidation reaction zone.

[0067] In some embodiments, for the system of the present invention, the temperature control device can control the inlet temperature of the feed to the inserted fresh catalyst bed or regenerated catalyst bed to satisfy the following equation (1a):

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[0068]

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[0069]

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[0070] In some embodiments, in the system of the present invention, the inlet and outlet of each catalyst bed are each independently equipped with a temperature detector. The temperature detector can detect the inlet temperature and outlet temperature of each catalyst bed and transmit the detected temperatures to a temperature control device. Various detectors commonly known in the art can be used as the temperature detector, as long as the required temperature detection function is achieved. For example, a thermocouple capable of transmitting a signal can be used as the temperature detector.

[0071] In the system of the present invention, the temperature control device can control the inlet temperature of the feed to the inserted fresh catalyst bed or the regenerated catalyst bed through a cooling element, preferably, the temperature control device controls the inlet temperature of the feed to the inserted fresh catalyst bed or the regenerated catalyst bed through a cooling element arranged on the connecting pipeline between two adjacent catalyst beds, and more preferably, the cooling element is electrically connected to the temperature control device.

[0072] For example, in some embodiments, the temperature controller collects the temperature detected by the temperature detector and calculates, based on the input values ​​of N, a1, and b1, according to Equation (1), Equation (1a), Equation (1b), Equation (1c), or Equation (2):

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[0073] In some embodiments, the cooling element can be an air-cooling element, a water-cooling element, or a heat-consolidating element. The temperature control device of the present invention can control the fan speed of the air-cooling element, control the valve of the water-cooling element to control the water flow rate, or control the valve of the heat-consolidating element to control the bypass flow rate.

[0074] The catalyst beds in the epoxidation reaction zone can each be supplemented with an epoxidation catalyst. The epoxidation catalyst can be any catalyst known in the art capable of carrying out an epoxidation reaction. Preferably, the epoxidation catalyst is a titanium-containing catalyst, more preferably at least one selected from titanium silicon molecular sieves, titanium dioxide, and combinations thereof.

[0075] In some embodiments, all temperature detectors at the inlet and outlet of the catalyst bed are electrically connected, for example, to a temperature controller. In some embodiments, the cooling element is electrically connected, for example, to a temperature controller.

[0076] In some embodiments, the temperature control device reduces the inlet temperature of the inserted fresh or regenerated catalyst bed located in the logical Nth stage via a cooling element positioned therein to control the inlet temperature within a desired range.

[0077] The temperature control device in the present application may be any of a variety of control devices generally known in the art, as long as they are capable of implementing the control functions disclosed herein. In some embodiments, the system of the present invention is preferably used to carry out the method of the present invention.

[0078] The range points and any values ​​disclosed in the present invention are not limited to exact ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values.For numerical ranges, the end values ​​of each range, the end values ​​of each range and each individual point value, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.Here, in principle, each technical solution can be combined with each other to obtain new technical solutions, which should also be considered to be specifically disclosed herein.

[0079] Compared with the prior art, the present invention can provide the following beneficial effects: (1) The system or method of the present invention can effectively control the temperature (alkylene oxide reaction temperature) of a catalyst bed newly added to the system or supplemented with a regenerated catalyst, thereby preventing runaway reactions due to an excessive rise in reaction temperature. (2) The system or method of the present invention can rationally control the temperature rise of the reaction system, thereby effectively preventing the occurrence of side reactions in the epoxidation reaction and improving the selectivity for the target product, propylene oxide. (3) The system or method of the present invention can save energy by rationally controlling the inlet temperature of a newly added catalyst bed to reduce the amount of cooling required.

[0080] 1 through 5 are schematic diagrams of several embodiments of the system of the present invention in which the epoxidation reaction zone comprises different numbers of reactors (ie, different total numbers of epoxidation catalyst beds).

[0081] In Figures 1 to 3, 1 represents feed propylene, 2 represents a cumene hydroperoxide solution containing alkylbenzene, 3 represents an epoxidation reaction product, C1 represents a propylene supply preheating element, C2 to C5 represent cooling elements between adjacent catalyst beds, respectively, and R1 to R6 represent catalyst bed 1, catalyst bed 2, catalyst bed 3, catalyst bed 4, catalyst bed 5, and catalyst bed 6, respectively.

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[0082]

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number

[0083] Taking FIG. 3 as an example, feed propylene 1 is preheated by propylene supply preheating element C1, mixed with a cumene hydroperoxide solution containing alkylbenzene, and then passes through catalyst bed 1 (the logical first-stage catalyst bed in the epoxidation reaction zone) from the top (designated R1 in the diagram). A newly introduced new or regenerated catalyst bed is designated R2 and is located downstream of R1. The stream discharged from the bottom outlet of catalyst bed 1 is cooled by cooling element C2 and passes through catalyst bed 2 from the top. Because the activity of the new or regenerated catalyst replenished in the newly introduced bed is relatively high, the control method of the present invention controls the inlet temperature of the newly introduced catalyst bed to be within the range defined by equation (1) to prevent the reactor outlet temperature from becoming too high or the degree of side reactions from worsening. Finally, stream 3 containing propylene oxide is obtained at the outlet of the reaction system.

[0084] BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of one embodiment of the system of the present invention, in which the epoxidation reaction zone comprises six reactors, ie, the total number of epoxidation catalyst beds is six. FIG. 2 is a schematic diagram of one embodiment of the system of the present invention, in which the epoxidation reaction zone comprises four reactors, ie, the total number of epoxidation catalyst beds is four. FIG. 3 is a schematic diagram of one embodiment of the system of the present invention, in which the epoxidation reaction zone comprises four reactors, ie, the total number of catalyst beds is four. FIG. 4 is a schematic diagram of one embodiment of the system of the present invention, in which the reaction zone comprises six reactors (N=6), ie, the total number of epoxidation catalyst beds is six. FIG. 5 is a schematic diagram of one embodiment of the system of the present invention, in which the reaction zone comprises five reactors (N=5), ie, the total number of epoxidation catalyst beds is five.

[0085] [Detailed explanation] The present invention will be described in detail below in conjunction with specific embodiments. It should be noted here that the following embodiments are only used to further describe the present invention and cannot be understood as limitations on the protection scope of the present invention. A number of non-essential improvements and adjustments made to the present invention by those skilled in the art based on the content of the present invention still fall within the protection scope of the present invention.

[0086] It should also be noted that the various specific technical features described in the following specific embodiments can be combined in any suitable manner without contradiction, and in order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0087] Furthermore, various embodiments of the present invention may be arbitrarily combined without going against the concept of the present invention, and the technical solutions thus formed are part of the disclosure of the original application of this specification and also belong to the protection scope of the present invention.

[0088] Unless otherwise specified, the raw materials and reagents used in the examples and comparative examples are purchased directly or prepared according to the preparation methods disclosed in the prior art. If necessary, the raw materials and reagents are subjected to conventional pretreatment to meet the reaction requirements.

[0089] The following examples and comparative examples used a catalyst prepared according to Example 1 of CN104437618B. In the examples of the present invention, the concentrations of each component in the outlet vapor of the epoxidation reaction zone were measured using liquid chromatography, and the conversion of cumene hydroperoxide and the selectivity of propylene oxide were calculated based on the concentrations. A Shimadzu LC-20 liquid chromatograph equipped with an autosampler and a diode array detector (DAD) was used.

[0090] Example 1 Propylene oxide was prepared using the reaction system shown in Figure 1. Specifically, the process included a cumene hydroperoxide stream with a mass flow rate of 100 kg / h, a cumene hydroperoxide feedstock mass concentration of 55 mass%, and a cumene mass concentration of 45 mass%. The mass flow rate of the propylene stream was 130.6 kg / h. To ensure proper liquid-phase reaction in the reactors, the reactor pressure was controlled at 6.0 MPaG, and the inlet temperature of each reactor was controlled between 40 and 130 °C. The inlet temperature was adjusted according to the outlet temperature so that the outlet temperature of each reactor did not exceed 130 °C. Epoxidation reactors R1, R2, R3, and R4 were each charged with 11.5 kg of catalyst, and epoxidation reactors R5 and R6 were charged with 14.7 kg of catalyst. The total mass space velocity of cumene hydroperoxide was 0.73 h. -1 The inlet temperature of the newly cut-out epoxidation reactor R4 in the epoxidation reaction system is calculated based on the following formula:

number

number

[0091] [Table 1]

[0092] Example 2 Propylene oxide was prepared using the reaction system shown in Figure 1. Specifically, the mass flow rate of the cumene hydroperoxide stream was 100 kg / h, the mass concentration of the cumene hydroperoxide feedstock was 55 mass%, and the mass concentration of cumene was 45 mass%. The mass flow rate of the propylene stream was 100.9 kg / h. To ensure proper liquid-phase reaction in the reactors, the reactor pressure was controlled at 6.0 MPaG. The inlet temperature of each reactor was controlled between 40 °C and 130 °C, and all inlet temperatures were adjusted according to the outlet temperature so that the outlet temperature of each reactor did not exceed 130 °C. Epoxidation reactors R1, R2, R3, and R4 were each charged with 5.1 kg of catalyst, and epoxidation reactors R5 and R6 were each charged with 10.2 kg of catalyst. The total mass hourly space velocity of cumene hydroperoxide was 1.35 h. -1 The inlet temperature of the newly inserted epoxidation reactor R4 in the epoxidation reaction system was calculated by the following formula:

number

number

[0093] [Table 2]

[0094] Example 3 Propylene oxide was prepared using the reaction system shown in Figure 1. Specifically, the following steps included a cumene hydroperoxide stream with a mass flow rate of 100 kg / h, a cumene hydroperoxide feedstock mass concentration of 40 mass%, and a cumene mass concentration of 60 mass%. The mass flow rate of the propylene stream was 52.1 kg / h. To ensure proper liquid-phase reaction in the reactors, the reactor pressure was controlled at 6.0 MPaG. The inlet temperature of each reactor was controlled between 40°C and 130°C, and the inlet temperature was adjusted according to the outlet temperature so that the outlet temperature of each reactor did not exceed 130°C. Epoxidation reactors R1, R2, R3, and R4 were each charged with 8.3 kg of catalyst, and epoxidation reactors R5 and R6 were each charged with 10.7 kg of catalyst. The total mass hourly space velocity of cumene hydroperoxide was 0.73 h. -1 The inlet temperature of the newly inserted epoxidation reactor R4 in the epoxidation reaction system was calculated by the following formula:

number

number

[0095] [Table 3]

[0096] Example 4 Propylene oxide was prepared using the reaction system shown in Figure 2. Specifically, the following steps included a cumene hydroperoxide stream with a mass flow rate of 100 kg / h, a cumene hydroperoxide feedstock mass concentration of 40 mass%, and a cumene mass concentration of 60 mass%. The mass flow rate of the propylene stream was 95 kg / h. To ensure proper liquid-phase reaction in the reactors, the reactor pressure was controlled at 6.0 MPaG. The inlet temperature of each reactor was controlled between 40°C and 130°C, and all inlet temperatures were adjusted according to the outlet temperature to ensure that the outlet temperature of each reactor did not exceed 130°C. Epoxidation reactors R1, R2, and R3 were each charged with 8.3 kg of catalyst, and epoxidation reactor R4 was charged with 10.7 kg of catalyst. The total mass hourly space velocity of cumene hydroperoxide was 1.12 h. -1 The inlet temperature of the newly inserted epoxidation reactor R3 in the epoxidation reaction system was calculated by the formula

number

number

[0097] [Table 4]

[0098] Example 5 Propylene oxide was prepared using the reaction system shown in Figure 3. Specifically, the following steps included a cumene hydroperoxide stream with a mass flow rate of 100 kg / h, a cumene hydroperoxide feedstock mass concentration of 40 mass%, and a cumene mass concentration of 60 mass%. The mass flow rate of the propylene stream was 95 kg / h. To ensure proper liquid-phase reaction in the reactors, the reactor pressure was controlled at 6.0 MPaG. The inlet temperature of each reactor was controlled between 40°C and 130°C, and all inlet temperatures were adjusted according to the outlet temperature so that the outlet temperature of each reactor did not exceed 130°C. Epoxidation reactors R1 and R2 were each charged with 11.7 kg of catalyst, and epoxidation reactors R3 and R4 were each charged with 9.0 kg of catalyst. The total mass hourly space velocity of cumene hydroperoxide was 0.97 h. -1 The inlet temperature of the newly inserted epoxidation reactor R2 in the epoxidation reaction system was calculated by the formula

number

number

[0099] [Table 5]

[0100] Example 6 As shown in Figure 4, the total number of epoxidation reactors was six. Propylene oxide was prepared using the reaction system shown in Figure 2. Specifically, the following steps included a cumene hydroperoxide stream with a mass flow rate of 100 kg / h, a cumene hydroperoxide feedstock mass concentration of 46 mass%, and a cumene mass concentration of 54 mass%. The mass flow rate of the propylene stream was 109 kg / h. To ensure proper liquid-phase reaction in the reactors, the reactor pressure was controlled at 6.0 MPaG. The inlet temperature of each reactor was controlled between 40 °C and 130 °C, and all inlet temperatures were adjusted according to the outlet temperature so that the outlet temperature of each reactor did not exceed 130 °C. Each epoxidation reactor was charged with 9.6 kg of catalyst, and the total mass hourly space velocity of cumene hydroperoxide was 0.80 h. -1 The newly installed N-stage epoxidation reactor was

number

number

number

[0101] [Table 6]

[0102] Example 7 As shown in Figure 4, the total number of epoxidation reactors was six. Propylene oxide was prepared using the reaction system shown in Figure 2. Specifically, the following steps included a cumene hydroperoxide stream with a mass flow rate of 100 kg / h, a cumene hydroperoxide feedstock mass concentration of 46 mass%, and a cumene mass concentration of 54 mass%. The mass flow rate of the propylene stream was 109 kg / h. To ensure proper liquid-phase reaction in the reactors, the reactor pressure was controlled at 6.0 MPaG. The inlet temperature of each reactor was controlled between 40 °C and 130 °C, and all inlet temperatures were adjusted according to the outlet temperature so that the outlet temperature of each reactor did not exceed 130 °C. Each epoxidation reactor was charged with 9.6 kg of catalyst, and the total mass hourly space velocity of cumene hydroperoxide was 0.80 h. -1 The newly installed N-stage epoxidation reactor was

number

number

number

[0103] [Table 7]

[0104] Example 8 As shown in Figure 5, the total number of epoxidation reactors was six. Propylene oxide was prepared using the reaction system shown in Figure 2. Specifically, the following steps included a cumene hydroperoxide stream with a mass flow rate of 100 kg / h, a cumene hydroperoxide feedstock mass concentration of 37 mass%, and a cumene mass concentration of 63 mass%. The mass flow rate of the propylene stream was 82 kg / h. To ensure proper liquid-phase reaction in the reactors, the reactor pressure was controlled at 6.0 MPaG. The inlet temperature of each reactor was controlled between 40 °C and 130 °C, and all inlet temperatures were adjusted according to the outlet temperature so that the outlet temperature of each reactor did not exceed 130 °C. Each epoxidation reactor was charged with 9.3 kg of catalyst, and the total mass space velocity of cumene hydroperoxide was 0.80 h. -1 The newly switched-over epoxidation reactor N stage was

number

number

number

[0105] [Table 8]

[0106] Example 9 The process of Example 6 was repeated except that the newly cut reactor was placed in the logical sixth, or last, stage of the epoxidation reaction system.

number

number

[0107] [Table 9]

[0108] [Comparative Example 1] The process of Example 1 was repeated except that only the catalyst bed was switched, but the inlet temperature of the newly inserted catalyst bed was not controlled, and in this case, the R4 inlet temperature was 126° C. and the R4 outlet temperature was 143° C. The outlet flow rate of the reaction zone was measured and calculated, and the conversion of cumene hydroperoxide was 99.4%, and the selectivity for propylene oxide was 87.5%.

[0109] Comparative Example 2 The process of Example 1 was repeated, except that the inlet temperature of the newly inserted new catalyst bed R4 was controlled by the following formula (5):

number

number

[0110] [Table 10]

[0111] Comparative Example 3 The steps of Example 1 were repeated, except that the numerator of the last fraction in equation (1) was 1200 instead of 1370. The inlet temperature of the newly inserted epoxidation reactor R4 in the epoxidation reaction system was calculated by the following equation:

number

number

[0112] Comparative Example 4 The steps of Example 1 were repeated, except that the numerator of the last fraction in equation (1) was 1600 instead of 1370. The inlet temperature of the newly inserted epoxidation reactor R4 in the epoxidation reaction system was calculated by the following equation:

number

number

[0113] Comparative Example 5 The process of Example 6 was repeated, except that the newly inserted reactor was placed in the logical second stage of the epoxidation reaction system.

number

number

[0114] Example 10 The procedure of Example 6 was repeated, except that the newly cut stage in the epoxidation reactor was different from that of Example 6.

number

number

number

[0115] [Table 11]

[0116] Example 11 As shown in Figure 5, the total number of epoxidation reactors was five. The mass flow rate of the cumene hydroperoxide stream was 100 kg / h, the mass concentration of the cumene hydroperoxide feedstock was 41 mass%, and the mass concentration of cumene was 59 mass%. The mass flow rate of the propylene stream was 87 kg / h. The reactor pressure was controlled at 6.0 MPaG to ensure proper liquid-phase reaction within the reactors. The inlet temperature of each reactor was controlled between 40°C and 130°C, and all inlet temperatures were adjusted based on the outlet temperature so that the outlet temperature of each reactor did not exceed 130°C. Each epoxidation reactor was charged with 9.3 kg of catalyst, and the total mass space velocity of cumene hydroperoxide was 0.80 h. -1 The newly installed N-stage epoxidation reactor was

number

number

number

[0117] [Table 12]

[0118] Example 12 As shown in Figure 4, the total number of epoxidation reactors was six. The mass flow rate of the cumene hydroperoxide stream was 100 kg / h, the mass concentration of the cumene hydroperoxide feedstock was 53 mass%, and the mass concentration of cumene was 47 mass%. The mass flow rate of the propylene stream was 81 kg / h. The reactor pressure was controlled at 6.0 MPaG to ensure proper liquid-phase reaction within the reactors. The inlet temperature of each reactor was controlled between 40°C and 130°C, and all inlet temperatures were adjusted according to the outlet temperature so that the outlet temperature of each reactor did not exceed 130°C. Each epoxidation reactor was charged with 9.6 kg of catalyst, and the total mass hourly space velocity of cumene hydroperoxide was 0.80 h. -1 The newly installed N-stage epoxidation reactor was

number

number

number

[0119] [Table 13]

[0120] Although the present invention has been described in detail above with specific embodiments and illustrative examples, these descriptions should not be construed as limitations on the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions of the present invention and its embodiments without departing from the spirit and scope of the present invention, and all of them are within the scope of the present invention. The protection scope of the present invention shall be determined by the appended claims. [Brief explanation of the drawings]

[0121] [Figure 1] 1 is a schematic diagram of one embodiment of the system of the present invention, in which the epoxidation reaction zone comprises six reactors, i.e., the total number of epoxidation catalyst beds is six. [Figure 2] 1 is a schematic diagram of one embodiment of the system of the present invention, in which the epoxidation reaction zone comprises four reactors, i.e., the total number of epoxidation catalyst beds is four. [Figure 3] 1 is a schematic diagram of one embodiment of the system of the present invention, in which the epoxidation reaction zone comprises four reactors, i.e., the total number of catalyst beds is four. [Figure 4] 1 is a schematic diagram of one embodiment of the system of the present invention, in which the reaction zone comprises six reactors (N=6), ie, the total number of epoxidation catalyst beds is six. [Figure 5]1 is a schematic diagram of one embodiment of the system of the present invention, in which the reaction zone comprises five reactors (N=5), i.e., the total number of epoxidation catalyst beds is five.

Claims

1. 1. A process for preparing an alkylene oxide, comprising: a step of supplying a feed comprising an olefin, an alkylbenzene hydroperoxide, and an alkylbenzene to an epoxidation reaction zone comprising at least two catalyst beds connected in series to carry out an epoxidation reaction and obtain a reaction product comprising an alkylene oxide; the feed enters a logical first catalyst bed of the at least two catalyst beds connected in series and passes sequentially through the at least two catalyst beds connected in series; When a catalyst bed, preferably the logical first stage catalyst bed, becomes deactivated, the catalyst bed is cut out and a new or regenerated catalyst bed is cut in; The inlet temperature of the feed entering the inserted fresh catalyst bed or regenerated catalyst bed satisfies the following formula (1) so that the temperature of the effluent leaving the inserted fresh catalyst bed or regenerated catalyst bed is 130°C or less: [Equation 1] In formula (1), [Equation 2] represents the inlet temperature of the new catalyst bed or the regenerated catalyst bed, and N represents that the inserted new catalyst bed or the regenerated catalyst bed is located at the logical Nth stage among the series-connected catalyst beds; [Equation 3] represents the outlet temperature of the catalyst bed at the logical stage i among the catalyst beds connected in series after the new catalyst bed or the regenerated catalyst bed is turned on, [Equation 4] represents the inlet temperature of the catalyst bed at logical stage i; [Equation 5] represents the sum of the temperature rise of all catalyst beds upstream of the inserted fresh or regenerated catalyst bed, and a １ represents the molar ratio of the olefin to the alkylbenzene hydroperoxide in the feed, and b １ represents the molar ratio of said alkylbenzene to said alkylbenzene hydroperoxide in said feed.

2. 1. A method for preparing alkylene oxide, comprising controlling the temperature of an effluent starting from a fresh catalyst bed or a regenerated catalyst bed to be 130°C or less, The method includes the steps of supplying a feed comprising an olefin, an alkylbenzene hydroperoxide, and an alkylbenzene to an epoxidation reaction zone comprising at least two catalyst beds connected in series to carry out an epoxidation reaction and obtain a reaction product comprising an alkylene oxide; the feed enters the logical first catalyst bed of the at least two catalyst beds connected in series and passes sequentially through the at least two catalyst beds connected in series; When the logical first stage catalyst bed is deactivated, the first stage catalyst bed is cut out and a new or regenerated catalyst bed is cut in; The method further comprises: the inlet temperature of the feed entering the inserted fresh catalyst bed or regenerated catalyst bed satisfies the following formula (1): [Equation 6] In formula (1), [Equation 7] represents the inlet temperature of the new catalyst bed or the regenerated catalyst bed, and N represents that the inserted new catalyst bed or the regenerated catalyst bed is located at the logical Nth stage among the series-connected catalyst beds; [Equation 8] represents the outlet temperature of the catalyst bed at the logical stage i among the catalyst beds connected in series after the new catalyst bed or the regenerated catalyst bed is turned on, [Equation 9] represents the inlet temperature of the catalyst bed at logical stage i; [Equation 10] represents the sum of the temperature rise of all catalyst beds upstream of the inserted fresh or regenerated catalyst bed, and a １ represents the molar ratio of the olefin to the alkylbenzene hydroperoxide in the feed, and b １ represents the molar ratio of said alkylbenzene to said alkylbenzene hydroperoxide in said feed.

3. The inlet temperature of the feed entering the inserted fresh catalyst bed or regenerated catalyst bed satisfies the following formula (1a): [0011] Preferably, the following formula (1b) is satisfied: [0012] Preferably, the following formula (1c) is satisfied: [0013] More preferably, the inlet temperature of the feed entering the inserted fresh catalyst bed or regenerated catalyst bed satisfies the following formula (2): [0014] In formula (1a), formula (1b), formula (1c) and formula (2), [Equation 15] a １ and b １ The method according to claim 1 or 2, characterized in that: is defined as in formula (1).

4. The inserted new catalyst bed or regenerated catalyst bed is located in a logical Nth stage among the catalyst beds connected in series, The sum of the temperature rises of the N-1 stage catalyst beds upstream of the new catalyst bed or the regenerated catalyst bed satisfies the following formula (3): [0016] Preferably, the following formula (4) is satisfied: [Equation 17] In formula (3) and formula (4), [Equation 18] a １ and b １ The method according to any one of claims 1 to 3, characterized in that is defined as in formula (1).

5. 5. The method according to claim 1, wherein the inserted new catalyst bed or regenerated catalyst bed is located at the logical final stage of the series-connected catalyst beds.

6. the epoxidation reaction zone comprises from 2 to 20, preferably from 3 to 20, preferably from 3 to 10, more preferably from 3 to 7, catalyst beds connected in series; and / or the catalyst bed in the epoxidation reaction zone is replenished with epoxidation catalyst; The method according to any one of claims 1 to 5, wherein the epoxidation catalyst is preferably a titanium-containing catalyst, more preferably at least one selected from titanium silicon molecular sieve, titanium dioxide and combinations thereof.

7. the alkylene oxide is selected from propylene oxide, ethylene oxide and butylene oxide, preferably propylene oxide; and / or the olefin is selected from ethylene, propylene, and butene, more preferably propylene; and / or the alkylbenzene hydroperoxide is cumene hydroperoxide, and / or the alkylbenzene is at least one selected from ethylbenzene, cumene, butylbenzene or a combination thereof, preferably cumene; and / or the molar ratio of the olefin to the alkylbenzene hydroperoxide is from 2 to 50, preferably from 2 to 12; and / or the alkylbenzene hydroperoxide is provided in the form of a solution, the solution comprising the alkylbenzene hydroperoxide and an alkylbenzene; Preferably, the alkylbenzene is at least one selected from ethylbenzene, cumene, and butylbenzene; More preferably, the method according to any one of claims 1 to 6, characterized in that the concentration of alkylbenzene in the solution is between 5% and 95% by weight.

8. Based on the total amount of catalyst, the mass space velocity of the alkylbenzene hydroperoxide is 0.1 to 3 h －１ , preferably 0.2 to 2 h －１ and / or The temperature of the epoxidation reaction is 0 to 200°C, and the pressure is 2 to 20 MPag; The method according to any one of claims 1 to 7, characterized in that the temperature of the epoxidation reaction is preferably 40 to 130°C and the pressure is 3 to 12 MPag.

9. 1. A system for preparing alkylene oxide, comprising: an epoxidation reaction zone comprising at least two catalyst beds connected in series; and a temperature control device, a feed comprising an olefin, an alkylbenzene hydroperoxide, and an alkylbenzene enters the epoxidation reaction zone and carries out an epoxidation reaction to obtain a product comprising an alkylene oxide; the feed enters the logical first catalyst bed of the at least two catalyst beds connected in series and passes sequentially through the at least two catalyst beds connected in series; The temperature control device controls the inlet temperature of the feed of the newly inserted new catalyst bed or the regenerated catalyst bed so as to satisfy the following formula (1): [Equation 19] In formula (1), [Equation 20] represents the inlet temperature of the new catalyst bed or the regenerated catalyst bed, and N represents that the inserted new catalyst bed or the regenerated catalyst bed is located at the logical Nth stage among the series-connected catalyst beds; [0000] represents the outlet temperature of the catalyst bed at the logical stage i among the catalyst beds connected in series after the new catalyst bed or the regenerated catalyst bed is turned on, [Equation 22] represents the inlet temperature of the catalyst bed at logical stage i; [Equation 23] represents the sum of the temperature rise of all catalyst beds upstream of the inserted fresh or regenerated catalyst bed, and a １ represents the molar ratio of the olefin to the alkylbenzene hydroperoxide in the feed, and b １ represents the molar ratio of the alkylbenzene to the alkylbenzene hydroperoxide in the feed.

10. The temperature control device controls the inlet temperature of the feed to the inserted new catalyst bed or regenerated catalyst bed so that the inlet temperature satisfies the following formula (1a): [0000] Preferably, the following formula (1b) is satisfied: [Equation 25] Preferably, the following formula (1c) is satisfied: [Equation 26] More preferably, the temperature control device controls the inlet temperature of the feed to the inserted new catalyst bed or regenerated catalyst bed so as to satisfy the following formula (2): [0000] In formula (1a), formula (1b), formula (1c) and formula (2), [0000] a １ and b １ The system of claim 9, wherein is defined similarly to equation (1).

11. The inserted new catalyst bed or regenerated catalyst bed is located in a logical Nth stage among the catalyst beds connected in series, The sum of the temperature rises of the N-1 stage catalyst beds upstream of the new catalyst bed or the regenerated catalyst bed satisfies the following formula (3): [0000] Preferably, the following formula (4) is satisfied: [Equation 30] In formula (3) and formula (4), [Equation 31] a １ and b １ 11. The system according to claim 9 or 10, characterized in that is defined similarly to equation (1).

12. an olefin supply pipeline and an alkylbenzene hydroperoxide supply pipeline connected to the first catalyst bed are located before the at least two catalyst beds connected in series; and / or a preheating element is disposed on the olefin supply pipeline, preferably the preheating element is a heater or a heat exchanger; and / or 12. The system according to claim 9, wherein a cooling element is arranged on the connecting pipeline between two adjacent catalyst beds.

13. the epoxidation reaction zone comprises from 2 to 20, preferably from 3 to 20, preferably from 3 to 10, preferably from 3 to 7, more preferably from 3 to 6, catalyst beds connected in series; and / or The inserted fresh or regenerated catalyst bed is located at the logical end of the series of catalyst beds; and / or the catalyst bed in the epoxidation reaction zone is replenished with epoxidation catalyst; 13. The system of any one of claims 9 to 12, wherein the epoxidation catalyst is preferably a titanium-containing catalyst, more preferably at least one selected from titanium silicon molecular sieve, titanium dioxide, and combinations thereof.

14. each catalyst bed inlet and outlet is independently equipped with a switching valve to switch the catalyst bed on or off; and / or The system further includes one or more fresh or regenerated catalyst beds inserted; the catalyst bed of the epoxidation reaction zone, preferably the logical first stage catalyst bed, is cut out after deactivation; and 14. The system of claim 9, wherein the fresh or regenerated catalyst bed is cut into the epoxidation reaction zone after the deactivated catalyst bed is cut out.

15. The inlet and outlet of each catalyst bed are each independently equipped with a temperature detector; and / or the temperature control device controls the inlet temperature of the feed to the inserted fresh or regenerated catalyst bed via a cooling element; Preferably, the temperature control device controls the inlet temperature of the feed to the inserted fresh catalyst bed or regenerated catalyst bed via a cooling element arranged on the connecting pipeline between two adjacent catalyst beds; More preferably, the system according to any one of claims 9 to 14, characterized in that the cooling element is electrically connected to the temperature control device.

16. the alkylene oxide is selected from propylene oxide, ethylene oxide and butylene oxide, preferably propylene oxide; and / or the olefin is selected from ethylene, propylene, and butene, more preferably propylene; and / or the alkylbenzene hydroperoxide is cumene hydroperoxide, and / or the alkylbenzene is at least one selected from ethylbenzene, cumene, butylbenzene or a combination thereof, preferably cumene; and / or the molar ratio of the olefin to the alkylbenzene hydroperoxide is from 2 to 50, preferably from 2 to 12; and / or the alkylbenzene hydroperoxide is provided in the form of a solution, and the solution comprises the alkylbenzene hydroperoxide and an alkylbenzene; Preferably, the alkylbenzene is at least one selected from ethylbenzene, cumene, and butylbenzene; More preferably, the concentration of alkylbenzene in the solution is 5% to 95% by mass.

17. Based on the total amount of catalyst, the mass space velocity of the alkylbenzene hydroperoxide is 0.1 to 3 h －１ , preferably 0.2 to 2 h －１ and / or The temperature of the epoxidation reaction is 0 to 200°C, and the pressure is 2 to 20 MPag; The system according to any one of claims 9 to 16, wherein the temperature of the epoxidation reaction is preferably 40 to 130°C and the pressure is preferably 3 to 12 MPag.

18. System according to any one of claims 9 to 17, characterized in that the system is used to carry out the method according to any one of claims 1 to 8.

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