Treatment method for reactor inactivation in alkylene oxide reaction system and application of treatment method

Abstract

The invention discloses a treatment method for reactor inactivation in an alkylene oxide reaction system and application of the treatment method, the alkylene oxide reaction system comprises one or more reactors, the alkylene oxide reaction system takes organic peroxide, olefin and a solvent as raw materials for reaction, the treatment method comprises the following steps: (1) stopping introducing organic peroxide into the reactor, (2) optionally introducing olefin and an optional solvent into the reactor, and (3) introducing the solvent into the reactor to enable materials in the reactor to flow into a recovery tank. According to the invention, after the feeding of the organic peroxide in a certain reactor in the system is stopped, the residual organic peroxide in the reactor can be completely converted, so that the safety of the reaction system is guaranteed; meanwhile, the raw material olefin in the reactor can be effectively recovered, so that the material consumption is reduced.

Description

Technical Field

[0001] The present invention relates to the field of alkylene oxide preparation, and in particular to a method for treating reactor deactivation in an alkylene oxide reaction system and application thereof. Background Art

[0002] Alkylene oxides are important raw materials for organic chemical synthesis. Industrial epoxidation reactions often utilize titanium-silicon catalysts. When the catalyst activity decreases or becomes deactivated, the reactor must be opened and replaced. Because the concentration of reactants gradually decreases with the direction of reaction flow, the degree of catalyst deactivation varies. This is particularly true for epoxidation reaction systems containing multiple reactors, where the catalyst deactivation is highest in the logically first reactor. When the catalyst in the logically first reactor reaches replacement conditions, the remaining reactors can continue to operate normally. Therefore, the reactor with the deactivated catalyst must be shut down under normal operating conditions to remove the catalyst and replace the catalyst.

[0003] Chinese patent CN1325484C discloses a fixed-bed reactor epoxidation system, a method for producing oxirane compounds by reacting an olefin and a hydroperoxide reactant in the presence of a solid epoxidation catalyst, wherein the olefin and the hydroperoxide reactant are first reacted in at least two fixed-bed reactors containing fresh catalyst, the olefin being fed sequentially into the reactors and the hydroperoxide being fed in parallel into the reactors, and thereafter the reactor effluent from the last of the reactors is passed through at least another reactor containing an at least partially deactivated epoxidation catalyst.

[0004] Chinese patent CN1449392A discloses a method for producing alkylene oxide using peroxide, wherein the alkylene oxide is produced by reacting an olefin with a peroxide in the presence of a catalyst and a solvent in at least two reactors arranged in series, each containing a portion of a catalyst. According to the method, peroxide is added only to the first reactor, and no fresh peroxide is added to the subsequent reactor or reactors. Instead, only peroxide present in the medium from the preceding reactor and not consumed in the preceding reactor is used.

[0005] However, the existing technology still has the problem of high energy consumption and affecting the entire epoxy process. Summary of the Invention

[0006] To overcome the problems existing in the prior art, the present invention provides a method for treating reactor deactivation in an alkylene oxide reaction system and its application. The alkylene oxide reaction system uses an organic peroxide and an olefin as raw materials, reacting in a reactor filled with a catalyst to produce alkylene oxide. When the catalyst in the reactor deactivates, the organic peroxide feed to the reactor is stopped, the olefin and an optional solvent are fed to the reactor to contact the catalyst, and a protective gas is supplied to the reactor. This method effectively solves the problem of incomplete conversion of the organic peroxide and olefin recovery in the reactor after the organic peroxide feed in the alkylene oxide reaction system is stopped, thereby ensuring production safety while saving material consumption and reducing operating costs.

[0007] A first aspect of the present invention provides a method for treating reactor deactivation in an alkylene oxide reaction system, wherein the alkylene oxide reaction system includes one or more reactors, and the alkylene oxide reaction system uses an organic peroxide, an olefin, and a solvent as raw materials for reaction, wherein the treatment method comprises: (1) stopping the introduction of the organic peroxide into the reactor, (2) optionally introducing an olefin and an optional solvent into the reactor, and (3) introducing a solvent into the reactor so that the material therein flows into a recovery tank.

[0008] The olefin in step (2) is preferably the same as the olefin in the raw material, and the solvent in step (3) is preferably the same as the solvent in the raw material.

[0009] During step (1) and / or step (2) and / or step (3), a protective gas is introduced into the reactor; preferably, the protective gas is selected from at least one of nitrogen, carbon dioxide, and an inert gas, preferably at least one of helium, neon, argon, nitrogen, and carbon dioxide.

[0010] Prior to step (2), the concentration of the organic peroxide at the reactor outlet is obtained; preferably, the concentration of the organic peroxide in the liquid phase from which olefins are removed in the reactor is obtained as follows:

[0011]

[0012] Where: is the mass concentration of organic peroxides without olefins at the reactor outlet; is the measured value of the mass concentration of organic peroxides at the reactor outlet; is the olefin mass concentration at the reactor outlet.

[0013] When the concentration of the organic peroxide in the liquid phase from which olefins are removed in the reactor is between 0 and 1 wt%, step (2) is not performed and step (3) is performed directly.

[0014] When the concentration of the organic peroxide in the liquid phase from which the olefin is removed in the reactor is greater than 1 wt%, step (2) comprises: introducing olefin and an optional solvent into the reactor; and simultaneously, obtaining in real time the concentration of the organic peroxide in the liquid phase from which the olefin is removed in the reactor, and stopping step (2) and proceeding to step (3) when the concentration is converted from greater than 1 wt% to 0-1 wt%.

[0015] After step (3), the pressure of the reactor is released; preferably, before releasing the pressure of the reactor, the olefin content in the reactor is detected, and the pressure of the reactor is released when the olefin content in the reactor is lower than 5 wt%.

[0016] When the solvent is introduced into the reactor and contacts the catalyst in the reactor, the linear velocity of the solvent flow in the reactor is in the range of 0.0001 to 0.5 cm / s.

[0017] When olefin is introduced into the reactor, the temperature of the reactor is controlled to be 10-200°C, preferably 40-130°C.

[0018] The second aspect of the present invention is to provide application of the treatment method described in the first aspect of the present invention in the preparation of alkylene oxide.

[0019] A third aspect of the present invention is to provide a method for preparing alkylene oxide, comprising: reacting raw materials including an organic peroxide, an olefin, and a solvent in a system including at least one reactor to prepare alkylene oxide, wherein each reactor is independently loaded with a catalyst, and when the catalyst in one of the reactors is deactivated, it is treated using the treatment method described in the first aspect of the present invention, while the remaining reactors are normally loaded and unloaded.

[0020] The organic peroxide is selected from at least one of hydrogen peroxide, ethylbenzene hydroperoxide, isopropylbenzene hydroperoxide, and tert-butyl hydroperoxide; and / or the olefin is selected from C2 to C10 olefins, preferably at least one of ethylene, propylene, and butene; and / or the solvent is selected from organic solvents, preferably at least one of alcohol solvents, aromatic solvents, and water, more preferably one or at least one of methanol, isobutane, ethylbenzene, isopropylbenzene, butylbenzene, and water.

[0021] In a preferred embodiment, under normal operation, the molar ratio of olefin to organic peroxide in the raw material is controlled to be 2-50.

[0022] Other conditions (e.g., temperature, pressure, etc.) under normal operation can be based on those disclosed in the prior art. For example, controlling the reactor outlet pressure to above 5.5 MPag can prevent olefins (e.g., propylene) from vaporizing at the reaction temperature. (Since this is a tandem reaction system, the overall pressure drop in the reaction system gradually increases with material flow. The pressure at the reactor outlet is the lowest point in the reaction system. Therefore, controlling the reactor outlet pressure can maintain the pressure of the entire reaction system above 5.5 MPag.)

[0023] In a preferred embodiment, deactivation is determined based on the temperature rise in the reactor.

[0024] In a further preferred embodiment, the reactor is deactivated when the temperature rises below 10°C. Preferably, the reactor is deactivated when the temperature rises below 10°C when the temperature is above 110°C.

[0025] The endpoints and any values ​​of the ranges disclosed in the present invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and a separate point value, and the separate point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered as specifically disclosed in this article. Hereinafter, in principle, each technical solution can be combined with each other to obtain a new technical solution, which should also be considered as specifically disclosed in this article.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) According to the present invention, after the feeding of organic peroxide to a reactor in the system is stopped, the residual organic peroxide in the reactor can be completely converted, thereby ensuring the safety of the reaction system;

[0028] (2) According to the present invention, after the organic peroxide feed to a reactor in the system is stopped, the raw olefin in the reactor can be effectively recovered, thus saving material consumption;

[0029] (3) According to the present invention, while ensuring production safety, material consumption is saved and operating costs are reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the normal operating conditions of the epoxidation system of the present invention. In the figure, the thick solid line indicates that there is material flow, and the thin dotted line indicates that there is no material flow in the pipeline.

[0031] Figure 1In the figure, 1 is an organic peroxide; 2 is an olefin; 3 is a solvent; 4 is an epoxidation reaction product; V1 is a propylene recovery tank; R1, R2, and R3 are epoxidation reactors filled with catalysts.

[0032] Figure 2 This is a schematic diagram of the peroxide feed stop of the R1 epoxidation reactor of the epoxidation system of the present invention. In the figure, the organic peroxide solution 1 is directly introduced into R2, the olefin 2 is continuously introduced into R1, and the organic peroxide concentration at the R1 outlet (reaction liquid without propylene) is continuously monitored.

[0033] Figure 3 This is a schematic diagram of the epoxidation system R1 reactor of the present invention in which both peroxide and olefin feeds are stopped. In the figure, organic peroxide solution 1 and olefin 2 are directly introduced into R2, and solvent 3 is introduced into R1 from the bottom of the reactor. The olefin in R1 is recovered to the propylene recovery tank V1. DETAILED DESCRIPTION

[0034] The following detailed description of the present invention will make the features and advantages of the present invention more clear and explicit.

[0035] One of the objects of the present invention is to provide a method for treating reactor deactivation in an alkylene oxide reaction system, wherein the alkylene oxide reaction system comprises one or more reactors, and the alkylene oxide reaction system uses an organic peroxide, an olefin, and a solvent as raw materials for reaction, wherein the treatment method comprises: (1) stopping the introduction of the organic peroxide into the reactor (referring to the reactor in which the catalyst is deactivated), (2) optionally introducing an olefin and an optional solvent into the reactor, and (3) introducing a solvent into the reactor so that the materials therein flow into a recovery tank.

[0036] When the reactor inlet temperature reaches 110°C (the activity of the epoxidation catalyst gradually decreases over the operating cycle; lower activity requires higher reaction temperatures), and the reactor temperature rise is less than 10°C, it indicates deactivation and requires catalyst replacement. The epoxidation reaction is exothermic; higher conversion rates increase with higher reaction temperature rises. Under the same conditions, higher catalyst activity increases conversion rates. When the reaction temperature reaches 110°C and the temperature rise is very low, it indicates that the catalyst activity has fallen below a certain level and catalyst replacement is necessary.

[0037] In a preferred embodiment, a protective gas is introduced into the reactor during step (1) and / or step (2) and / or step (3).

[0038] In a further preferred embodiment, the protective gas is selected from at least one of nitrogen, carbon dioxide, and an inert gas, preferably at least one of helium, neon, argon, nitrogen, and carbon dioxide.

[0039] In a preferred embodiment, the concentration of the organic peroxide at the outlet of the reactor is first obtained before step (2).

[0040] When sampling and analyzing the concentration of organic peroxides at the reactor outlet, the reactor outlet needs to be cooled and decompressed. During this process, olefins will flash, resulting in a large change in the concentration of olefins in the liquid phase. Therefore, the organic peroxide concentration in the present invention is calculated based on the liquid phase after deducting the olefins.

[0041] In a further preferred embodiment, the concentration of the organic peroxide in the liquid phase from which olefins are removed in the reactor is obtained as follows:

[0042]

[0043] Where: is the mass concentration of organic peroxides without olefins at the reactor outlet; is the measured value of the mass concentration of organic peroxides at the reactor outlet (i.e., the measured value of sampling at the reactor outlet. After cooling and decompression, there will still be a certain concentration of olefins in the liquid phase); is the mass concentration of olefins at the reactor outlet (after the reactor outlet is cooled and decompressed for sampling, there will still be a certain concentration of propylene in the liquid phase; the above data is the concentration of propylene in the liquid phase).

[0044] Among them, the concentration of organic peroxides at the outlet of the fixed bed reactor was measured Methods including but not limited to iodine titration (iodine titration), near infrared analysis (NIR) or liquid chromatography (LC); Determination of the mass concentration of olefins at the reactor outlet Using liquid chromatography.

[0045] In a preferred embodiment, when the concentration of the organic peroxide in the liquid phase from which olefins are removed in the reactor is 0 to 1 wt%, step (2) is not performed and step (3) is performed directly.

[0046] When the organic peroxide concentration is between 0 and 1 wt%, the organic peroxide content is already very low. If olefins are introduced into the reactor at this time, it would be a redundant process, wasting manpower and time, and increasing material consumption. Therefore, solvent is introduced directly into the reactor so that the material therein flows into a recovery tank.

[0047] In a preferred embodiment, when the concentration of the organic peroxide in the liquid phase from which the olefin is removed in the reactor is greater than 1 wt%, step (2) comprises: introducing olefin and an optional solvent into the reactor; and simultaneously, obtaining in real time the concentration of the organic peroxide in the liquid phase from which the olefin is removed in the reactor, and stopping step (2) and proceeding to step (3) when the concentration is converted from greater than 1 wt% to 0-1 wt%.

[0048] When the concentration of the organic peroxide is greater than 1 wt%, an olefin and an optional solvent need to be introduced to allow the organic peroxide to fully react. Therefore, the method of the present invention is preferably used in a deactivation reactor in which the concentration of the organic peroxide in the liquid phase of the olefin removal reactor is greater than 1 wt%.

[0049] In a preferred embodiment, the pressure of the reactor is released after step (3).

[0050] In a further preferred embodiment, before releasing the pressure of the reactor, the olefin content in the reactor is detected, and the pressure of the reactor is released when the olefin content in the reactor is lower than 5 wt%.

[0051] Wherein, protective gas is applied before, after or during pressure release.

[0052] In a preferred embodiment, the system comprises one or more reactors, each of which is filled with a catalyst. The reactor deactivation in the present invention refers to the deactivation of the catalyst in the reactor.

[0053] In a further preferred embodiment, when the system comprises a plurality of reactors, the plurality of reactors are arranged in parallel or in series or in series-parallel or in parallel-series.

[0054] In a further preferred embodiment, when the catalyst in one of the reactors is deactivated, the above operations (1) to (3) are performed on the deactivated reactor, and the remaining reactors are normally loaded and unloaded.

[0055] In a preferred embodiment, the reaction is performed in pure liquid phase.

[0056] In a further preferred embodiment, the reactor is a fixed bed reactor.

[0057] In a preferred embodiment, when the solvent is introduced into the reactor, when the solvent contacts the catalyst in the reactor, the linear velocity of the solvent flow in the reactor is in the range of 0.0001 to 0.5 cm / s, for example, 0.0001 cm / s, 0.0005 cm / s, 0.001 cm / s, 0.005 cm / s, 0.01 cm / s, 0.05 cm / s, 0.1 cm / s, 0.2 cm / s, 0.3 cm / s, 0.4 cm / s or 0.5 cm / s.

[0058] The inventors, through extensive experiments, found that when the solvent linear velocity exceeds 0.5 cm / s, the catalyst bed can be damaged. For example, if the linear velocity is greater than the catalyst settling velocity, the catalyst can be entrained and the bed morphology can be disrupted. When the solvent linear velocity is less than 0.0001 cm / s, the solvent purge time is excessively long.

[0059] In a preferred embodiment, when olefin is introduced into the reactor, the temperature of the reactor is controlled to be 10-200°C, preferably 40-130°C, for example, 10°C, 30°C, 50°C, 80°C, 100°C, 120°C, 150°C, 180°C or 200°C.

[0060] A second object of the present invention is to provide an application of the treatment method described in the first object of the present invention in the preparation of alkylene oxide.

[0061] A third object of the present invention is to provide a method for preparing alkylene oxide, comprising: reacting raw materials including an organic peroxide, an olefin, and a solvent in a system including at least one reactor to prepare alkylene oxide, wherein each reactor is independently loaded with a catalyst, and when the catalyst in one of the reactors is deactivated, it is treated using the treatment method described in one of the objects of the present invention, while the remaining reactors are normally loaded and unloaded.

[0062] In a preferred embodiment, the organic peroxide is at least one selected from hydrogen peroxide, ethylbenzene hydroperoxide, cumene hydroperoxide, and tert-butyl hydroperoxide.

[0063] In a preferred embodiment, the olefin is selected from C2 to C10 olefins, preferably at least one selected from ethylene, propylene, and butene.

[0064] In a preferred embodiment, the solvent is selected from an organic solvent, preferably at least one of an alcohol solvent, an aromatic solvent, and water, more preferably one or at least one of methanol, isobutane, ethylbenzene, cumene, butylbenzene, and water.

[0065] In a preferred embodiment, under normal start-up conditions, the molar ratio of olefin to organic peroxide in the feedstock is controlled to be 2 to 50, for example, 2, 5, 10, 20, 30, 40 or 50.

[0066] In a preferred embodiment, the catalyst is selected from any catalyst disclosed in the prior art that can be used to prepare alkylene oxide from organic peroxides and olefins, preferably but not limited to titanium-containing catalysts such as titanium silicalite and / or titanium dioxide.

[0067] Example

[0068] The present invention will be described in detail below with reference to specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and are not to be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made by those skilled in the art to the present invention based on the contents of the present invention still fall within the scope of protection of the present invention.

[0069] It should also be noted that the various specific technical features described in the following specific embodiments can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0070] In addition, the various embodiments of the present invention may be arbitrarily combined as long as they do not violate the concept of the present invention. The technical solutions thus formed belong to part of the original disclosure of this specification and also fall within the scope of protection of the present invention.

[0071] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, for example, they can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0072] The reactor is filled with a catalyst prepared according to patent CN104437618B "Catalyst, preparation method and application of propylene for preparing propylene oxide": 280g of n-hexadecylamine is slowly added to a mixed solution of 2500g of deionized water and 1300g of ethanol under stirring at 45°C to form a transparent solution A; 36g of tridecafluorooctyltrimethoxysilane and 30g of tetrabutyl titanate are simultaneously added to a mixed solution consisting of 240g of isopropanol and 480g of tetraethyl orthosilicate, and stirred for 60min to form a solution B; solution B is slowly added to solution A, stirred for 24h, filtered, washed, dried at 120°C for 12h, and then refluxed in a solution consisting of ethanol and a small amount of aqueous hydrochloric acid solution (0.2mol) for 2h to remove the residual template, filtered, washed and filtered, and repeated three times. The filtered product is dried at 120°C for 24h and heated at 200°C under a nitrogen atmosphere for 6h to obtain a white solid powder. The reaction mixture has the following molar ratios: Ti / Si = 0.0370, n-hexadecylamine / Si = 0.4873, water / Si = 58.2488, water / alcohol = 4.3056, and tridecafluorooctyltrimethoxysilane / tetraethyl orthosilicate = 0.0333. 100 g of the powdered sample prepared above was added to a 250 ml cumene bath containing 40 g of hexamethyldisilazane. The mixture was heated to 150° C. with rapid stirring and reflux, and allowed to react at this temperature for 4 hours. The remaining hexamethyldisilazane and cumene solvent were then evaporated under vacuum at this temperature to obtain a porous silica catalyst having highly dispersed active components and highly hydrophobic and partially oleophobic properties.

[0073] [Example 1]

[0074] Taking a 300,000 t / a cumene hydroperoxide epoxidation system to produce propylene oxide as an example, the system includes three reactors connected in series, each reactor being filled with a catalyst, which is the aforementioned titanium silicon catalyst.

[0075] In this embodiment, the solvent 3 is cumene, the olefin is propylene, and the organic peroxide is cumene hydroperoxide.

[0076] like Figure 1 As shown, under normal operating conditions, 185.8 t / h of cumene hydroperoxide 1 is mixed with propylene 2 and then introduced into the epoxidation reaction system, wherein the molar ratio of propylene to cumene hydroperoxide is 8. The epoxidation reaction system is equipped with three reactors, and the reactor outlet pressure is controlled at above 5.5 MPag. The reaction mixture passes through reactors R1, R2 and R3 in sequence to finally obtain a liquid phase composition containing propylene oxide product, and the subsequent components enter the distillation system for separation.

[0077] like Figure 2 As shown, when the catalyst in reactor R1 reaches the catalyst replacement condition, that is, when the inlet temperature reaches 110°C, the temperature rise of reactor R1 is less than 10°C. The feeding of cumene hydroperoxide into reactor R1 is stopped. Since there is still unreacted cumene hydroperoxide in reactor R1 (and the cumene hydroperoxide concentration in the reaction liquid without propylene is 30 wt%), propylene is continued to be fed into R1 until the cumene hydroperoxide concentration at the outlet of reactor R1 (in the reaction liquid without propylene) is less than 1 wt% (the propylene feeding is then stopped, and the temperature of the entire propylene feeding process is controlled within a range of 40-130°C).

[0078] like Figure 3 As shown, propylene feed to reactor R1 is stopped and the system is directly mixed with cumene hydroperoxide before being introduced into reactor R2. Because R1 contains a large amount of propylene, cumene solvent is introduced from the bottom of reactor R1 (the linear velocity of the cumene flow in the reactor is controlled within the range of 0.0001 to 0.5 cm / s). The propylene in reactor R1 is recovered to propylene recovery tank V1. When the propylene content in the reactor falls below 5 wt%, the pressure in reactor R1 is released. Subsequent solvent recovery, purging, replacement, and solvent exchange operations are performed in reactor R1 as needed.

[0079] [Example 2]

[0080] The process was operated under the same conditions as in Example 1, except that when the catalyst in reactor R3 reached the catalyst replacement condition, the concentration of cumene hydroperoxide in the propylene-free reaction liquid at the reactor outlet was measured to be 0.8 wt%. At this point, reactor R3 was isolated from the other reactors, and cumene solvent was introduced directly from the bottom of reactor R3 (the linear velocity of cumene flow in the reactor was controlled to be within the range of 0.0001 to 0.5 cm / s). The propylene and cumene in reactor R1 were recovered to propylene recovery tank V1. When the propylene content in the reactor fell below 5 wt%, the pressure in reactor R3 was released. Subsequent solvent recovery, purging, replacement, and catalyst replacement were performed in reactor R3 as needed.

[0081] [Example 3]

[0082] The same process operating conditions as in Example 1 were used, except that when the catalyst in reactor R2 reached the catalyst replacement condition, the cumene hydroperoxide concentration in the propylene-free reaction solution at its reactor outlet was measured to be 10wt%. Propylene 2 was continued to be fed into R2 until the cumene hydroperoxide concentration at the reactor R2 outlet (the propylene-free reaction solution) was less than 1wt% (then the propylene feed was stopped). Reactor R2 was isolated from the other reactors, and cumene solvent was fed from the bottom of reactor R2 (controlling the linear velocity of the cumene flow in the reactor to be within the range of 0.0001 to 0.5cm / s). The propylene in reactor R2 was recovered to propylene recovery tank V1. When the propylene content in the reactor was less than 5wt%, reactor R2 was depressurized. Subsequent reactor R2 was subjected to solvent discharge recovery, purging, replacement, and catalyst replacement operations as needed.

[0083] [Comparative Example 1]

[0084] Repeat the process in Example 1, except that Figure 2 As shown, when the feed of cumene hydroperoxide 1 to reactor R1 is stopped, the flow of propylene 2 into R1 is also stopped, meaning that both cumene hydroperoxide 1 and propylene 2 are simultaneously bypassed to reactor R2. Because reactor R1 contains a large amount of incompletely converted cumene hydroperoxide, directly replacing reactor R1 with cumene solvent would result in loss of cumene hydroperoxide in reactor R1, increasing reactant consumption. Furthermore, the process of replacing the cumene solvent with return tank V1 can easily lead to thermal decomposition of the cumene hydroperoxide, which can cause a temperature runaway.

[0085] [Comparative Example 2]

[0086] Repeat the process in Example 1, except that Figure 3As shown, reactor R1 contains a large amount of propylene. Isopropyl benzene solvent is introduced from the bottom of reactor R1 to recover the propylene in reactor R1 into propylene recovery tank V1. When reactor R1 is depressurized, the propylene content is 10 wt%. This depressurization process causes reactor R1 to cool, which in turn lowers the temperature of the entire system and even causes the byproduct water produced within the system to freeze, severely impacting the overall production performance. Analysis suggests that due to the high propylene content in reactor R1, the propylene may vaporize during the depressurization process, lowering the temperature of reactor R1 and the entire system.

[0087] 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 appreciate that various equivalent substitutions, modifications, or improvements may be made to the technical solutions and implementations of the present invention without departing from the spirit and scope of the present invention, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A method for treating reactor deactivation in an alkylene oxide reaction system, wherein the alkylene oxide reaction system comprises one or more reactors, and the alkylene oxide reaction system uses organic peroxide, olefin, and solvent as raw materials for reaction, wherein: The treatment method comprises: (1) stopping the introduction of organic peroxide into the reactor, (2) optionally introducing olefin and optional solvent into the reactor, and (3) introducing solvent into the reactor so that the material therein flows into a recovery tank.

2. The processing method according to claim 1, characterized in that: During step (1) and / or step (2) and / or step (3), a protective gas is introduced into the reactor; preferably, the protective gas is selected from at least one of nitrogen, carbon dioxide, and an inert gas, preferably at least one of helium, neon, argon, nitrogen, and carbon dioxide.

3. The processing method according to claim 1, characterized in that: Prior to step (2), the concentration of the organic peroxide at the outlet of the reactor is first obtained; preferably, the concentration of the organic peroxide in the liquid phase from which olefins are removed in the reactor is obtained as follows: Where: is the mass concentration of organic peroxides without olefins at the reactor outlet; is the measured value of the mass concentration of organic peroxide at the reactor outlet; is the olefin mass concentration at the reactor outlet.

4. The processing method according to claim 1, characterized in that: When the concentration of the organic peroxide in the liquid phase from which olefins are removed in the reactor is between 0 and 1 wt %, step (2) is not performed and step (3) is performed directly.

5. The processing method according to claim 1, characterized in that: When the concentration of the organic peroxide in the liquid phase from which the olefin is removed in the reactor is greater than 1 wt %, step (2) comprises: introducing olefin and an optional solvent into the reactor; and simultaneously, obtaining in real time the concentration of the organic peroxide in the liquid phase from which the olefin is removed in the reactor, and stopping step (2) and proceeding to step (3) when the concentration of the organic peroxide in the liquid phase from which the olefin is removed is converted from greater than 1 wt % to 0-1 wt %.

6. The processing method according to claim 1, characterized in that: After step (3), the pressure of the reactor is released; preferably, before the pressure of the reactor is released, the olefin content in the reactor is detected, and the pressure of the reactor is released when the olefin content in the reactor is lower than 5 wt%.

7. The processing method according to any one of claims 1 to 6, characterized in that: When the solvent is introduced into the reactor, when the solvent contacts the catalyst in the reactor, the linear velocity of the solvent flow in the reactor is in the range of 0.0001 to 0.5 cm / s.

8. The processing method according to claim 7, characterized in that: When olefin is introduced into the reactor, the temperature of the reactor is controlled to be 10-200°C, preferably 40-130°C.

9. Use of the treatment method according to any one of claims 1 to 8 in the preparation of alkylene oxide.

10. A method for preparing alkylene oxide, comprising: Raw materials including organic peroxide, olefin and solvent are reacted in a system including at least one reactor to prepare alkylene oxide, wherein each reactor is independently loaded with a catalyst, and when the catalyst in one of the reactors is deactivated, it is treated by the treatment method according to one of claims 1 to 8, and the remaining reactors are normally loaded and unloaded.

11. The preparation method according to claim 10, characterized in that: The organic peroxide is at least one selected from hydrogen peroxide, ethylbenzene hydroperoxide, cumene hydroperoxide, and tert-butyl hydroperoxide; and / or, The olefin is selected from C2 to C10 olefins, preferably at least one selected from ethylene, propylene and butene; and / or, The solvent is selected from organic solvents, preferably at least one of alcohol solvents, aromatic solvents and water, more preferably one or more of methanol, isobutane, ethylbenzene, isopropylbenzene, butylbenzene and water.

12. The preparation method according to claim 10 or 11, characterized in that: Under normal operation conditions, the molar ratio of olefin to organic peroxide in the raw material is controlled to be 2-50.

Images