Multi-stage fluidized bed reactor for olefin esterification

Abstract

The invention provides a multi-stage fluidized bed reactor for olefin esterification, relates to the technical field of esterification reaction equipment, and solves the technical problems of non-uniform raw material mixing, shutdown replacement of a catalyst, unstable sulfuric acid concentration, large mass transfer resistance and low reaction conversion rate in the prior art. The reactor integrates a raw material secondary mixing system, a catalyst on-line cyclic regeneration system, a sulfuric acid concentration stabilizing system, a reaction liquid multi-stage circulating system and a pressurized mass transfer strengthening system, and through the collaborative design of'space + micropore 'secondary mixing, catalyst on-line activation and reflux, sulfuric acid dynamic regulation and control, multi-stage reaction circulation and Npressurized liquefied olefin, the reaction liquid in the reactor can be recycled. The raw material contact efficiency, the production continuity and the reaction conversion rate are remarkably improved, and the industrial olefin esterification production requirements are met.

Description

Technical Field

[0001] This invention relates to the field of fine chemical reaction equipment technology, specifically to a multi-stage fluidized bed reactor for olefin esterification reactions, which is particularly suitable for industrial esterification production requiring efficient mixing, continuous use of catalysts, enhanced mass transfer, and stable reaction conditions. Background Technology

[0002] Olefin esterification is a core process for preparing ester compounds, widely used in the production of solvents, plasticizers, and pharmaceutical intermediates. Currently, the main processes for preparing ester compounds are those involving carboxylic acids and alcohols or acid anhydrides and alcohols. Reports on olefin esterification processes are relatively few, primarily because olefin esterification is more challenging than traditional processes, presenting not only with the problem of olefin polymerization at high temperatures but also with mass transfer issues and low conversion rates. Traditional single-stage reactors struggle to achieve ideal reaction results; excessively pursuing high conversion rates by increasing reaction temperatures can easily lead to reduced selectivity in olefin polymerization and even pipeline blockage. Traditional resin catalysts have short lifespans, and the high costs associated with frequent catalyst replacements significantly reduce the process's competitiveness. Therefore, new reactors need to overcome the following technical shortcomings: Poor mixing of raw materials: Olefins and acetic acid have different physical properties. Existing equipment mostly uses a single mixing method, which makes it difficult for the two raw materials to achieve sufficient contact, resulting in uneven local concentrations. This not only reduces the reaction rate but also easily triggers side reactions. Low catalyst utilization: The solid acid catalyst used in the reaction is prone to acid component shedding and metal ion poisoning during the reaction process, resulting in deactivation. Existing equipment requires shutdown to remove the catalyst for regeneration or replacement, which seriously interrupts the continuity of production and increases labor and material costs. Sulfuric acid concentration runaway: Sulfuric acid, as a co-catalyst for esterification reaction, will be lost with the product or its concentration will decrease due to dilution during the reaction. Existing equipment lacks an effective concentration control mechanism, which leads to a continuous decline in catalytic efficiency. High mass transfer resistance: When olefins are in the gaseous state, the interfacial contact with liquid acetic acid is limited, resulting in low mass transfer efficiency and limiting the reaction rate. Limited reaction conversion rate: The residence time of raw materials in the single-stage reaction system is insufficient, and there is no effective means to enhance the circulation of the reaction liquid. Some unreacted raw materials directly enter the post-processing system, resulting in a low overall conversion rate.

[0003] To address the aforementioned issues, there is an urgent need to design a novel reactor capable of efficient raw material mixing, online catalyst regeneration, enhanced mass transfer, and stable control of reaction conditions, in order to improve the industrial production efficiency and product quality of olefin esterification reactions.

[0004] CN 102911044B proposes a method for preparing sec-butyl acetate by addition reaction of n-butene. n-Butene, a reaction solvent, and acetic acid undergo an addition reaction in a fixed-bed reactor equipped with a strongly acidic cation exchange resin catalyst to prepare sec-butyl acetate. The reaction solvent is used to enhance mass transfer in the reaction system. However, using an ester solvent easily leads to transesterification, increasing both cost and the difficulty of the separation system. CN 101293824B proposes a method for preparing sec-butyl acetate from acetic acid and butene, using a heteropolyacid as a catalyst. Butene is used as a raw material to react with acetic acid to prepare sec-butyl acetate. The reactors used include a fixed-bed reactor and a batch reactor, resulting in low mass transfer efficiency, and the use of a heteropolyacid catalyst is unsuitable for industrial application. US5994578 reports the reaction of olefins with lower carboxylic acids in the presence of solvents such as tert-butanol, which reduces the formation of olefin dimers, allowing the reaction to mainly produce ester products. However, the addition of a reaction solvent, and the tendency of tert-butanol to form di-tert-butyl ether in a fixed-acid catalyst, increases both solvent cost and separation difficulty.

[0005] CN 103333065 B A method for the continuous production of isopentenyl acetate, comprising preparing a solution by continuously passing isoprene and acetic acid, after gasification, through a fixed-bed catalyst bed composed of granular Zn(AC)2 / C, to carry out an esterification reaction, thereby converting isoprene and acetic acid into isopentenyl acetate within the reactor. While the gas-phase reaction eliminates mass transfer problems, the decrease in selectivity due to high temperature is unavoidable, and the catalyst system lacks a regeneration system, posing significant challenges for industrialization. Summary of the Invention

[0006] The main objective of this application is to provide a multi-stage fluidized bed reactor for olefin esterification, which solves the technical problems of uneven raw material mixing, catalyst replacement requiring shutdown, unstable sulfuric acid concentration, high mass transfer resistance, and low reaction conversion rate in existing reactors.

[0007] To achieve the above objectives, in a first aspect, this application provides a multi-stage fluidized bed reactor for olefin esterification, comprising at least two stages of fluidized bed reaction units connected in series. Each fluidized bed reaction unit includes a fluidized bed reactor body, an olefin delivery pipeline connected to the bottom of the fluidized bed reactor body, an acetic acid delivery pipeline connected to the bottom of the fluidized bed reactor body, an acetic acid distributor disposed within the fluidized bed reactor body and connected to the acetic acid delivery pipeline, an input pipeline connected to the top of the fluidized bed reactor body, a solid acid catalyst bed disposed in the middle of the fluidized bed reactor body, and a catalyst bed disposed in the middle of the fluidized bed reactor body. The reactor includes a deactivated catalyst extraction pipeline, a reaction liquid hydrocyclone separator connected to the deactivated catalyst extraction pipeline, a liquid phase outlet of the reaction liquid hydrocyclone separator connected to the upper part of the fluidized bed reactor body, a solid phase outlet of the reaction liquid hydrocyclone separator connected to an activation reactor, a jacket provided outside the activation reactor, a hot fluid medium flowing through the jacket, a sulfuric acid hydrocyclone separator connected to the activation reactor, a sulfuric acid storage tank connected to the liquid phase outlet of the sulfuric acid hydrocyclone separator, and a reflux channel provided with a solid-liquid mixing and conveying pump connected to the fluidized bed reactor body, with a flushing acetic acid inlet connected to the reflux channel. The reaction liquid outlet of the fluidized bed reactor body is connected to a reaction liquid buffer tank. The reaction liquid buffer tank of the first-stage fluidized bed reactor body is connected to the olefin delivery pipeline of the second-stage fluidized bed reactor body through a delivery pipeline. The reaction liquid buffer tank of the final-stage fluidized bed reactor body is connected to the acetic acid delivery pipeline of the first-stage fluidized bed reactor body through a return pipeline. A reaction liquid delivery pump and a preheater are installed on the delivery pipeline.

[0008] Optionally, microporous distributors are provided on both the upper and lower sides of the acetic acid distributor.

[0009] Optionally, a heater is provided on the acetic acid delivery pipeline.

[0010] Optionally, the jacket is provided with a heat medium inlet and a heat medium outlet.

[0011] Optionally, the heat medium is at least one of hot steam, heat transfer oil, and hot water.

[0012] Optionally, a pressure regulating valve is provided on the input pipeline.

[0013] Optionally, a catalyst baffle is provided above the solid acid catalyst bed.

[0014] Optionally, the sulfuric acid storage tank is equipped with a concentration monitor and connected to a sulfuric acid supply port.

[0015] Optionally, the sulfuric acid storage tank is connected to the activation reactor via a circulation pipeline, and the circulation pipeline is equipped with a sulfuric acid transfer pump and a one-way valve.

[0016] Optionally, a sulfuric acid discharge port is connected to the connecting pipe between the sulfuric acid hydrocyclone separator and the sulfuric acid storage tank.

[0017] The present invention provides a multi-stage fluidized bed reactor and method for olefin esterification. Compared with the prior art, its advantages are as follows: it innovatively adopts a "spatial primary mixing + microporous secondary mixing" mode, which improves the uniformity of raw material mixing by more than 40%, effectively reduces side reactions, and increases the reaction rate by 25%-35%. Production continuity assurance: The online catalyst recycling system enables uninterrupted regeneration and reflux of deactivated catalysts without the need for shutdown for replacement, extending continuous production time to more than 30 days and increasing production efficiency by 50%; Stable catalytic effect: The sulfuric acid concentration maintenance system controls the fluctuation of sulfuric acid concentration within ±0.5% through dynamic replenishment and reflux adjustment, ensuring continuous and stable catalytic efficiency; Mass transfer resistance is significantly reduced: Nitrogen or an inert gas can be added to the input pipeline, with nitrogen being preferred. The N2 pressurization liquefies the olefins, increases the interfacial contact area, reduces the mass transfer resistance by more than 60%, and further promotes the efficient reaction. Improved feed conversion rate: The combination design of multi-stage series reactor and reaction liquid circulation, combined with the mass transfer enhancement effect, increases the olefin conversion rate from 70%-80% in traditional single-stage reactors to over 90%. Compact and easy to operate: The integrated design of each system ensures a smooth process. It can be adapted to different production loads by adjusting parameters such as the temperature of the heat medium, the circulation flow rate, and the N2 injection rate, resulting in low maintenance costs. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of the application and to make other features, objects, and advantages of the application more apparent. The illustrative embodiments and descriptions of this application are used to explain the application and do not constitute an undue limitation of the application. In the drawings: Figure 1 This is a schematic diagram of a single-stage fluidized bed reactor; Figure 2 This is a schematic diagram of the present invention.

[0019] The components include: 1. Heater; 2. Acetic acid distributor; 3. Microporous distributor; 4. Catalyst baffle; 5. Fluidized bed reactor body; 6. Reaction liquid buffer tank; 7. Reaction liquid transfer pump; 8. Reaction liquid hydrocyclone separator; 9. Activation reactor; 10. Sulfuric acid hydrocyclone separator; 11. Sulfuric acid storage tank; 12. Sulfuric acid transfer pump; 13. Check valve; 14. Solid-liquid mixing transfer pump; 15. Concentration monitor; 16. Pressure regulating valve; 17. Acetic acid flushing inlet; 19. Olefin inlet; 20. Heat medium inlet; 21. Heat medium outlet. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0021] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0023] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0024] In addition, the term "multiple" should mean two or more.

[0025] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] like Figures 1-2 As shown, the multi-stage fluidized bed reactor for olefin esterification in this embodiment includes a primary fluidized bed reactor body 5, a secondary fluidized bed reactor, and various supporting functional systems. The specific operation flow is as follows: Raw material preparation and mixing: Acetic acid enters heater 1 through a delivery pipeline, is heated to 70°C, and then sent to acetic acid distributor 2; olefins are sent to microporous distributor 3 through olefin inlet 19, with a pore size of 20μm; acetic acid and olefins are first mixed in the space between acetic acid distributor 2 and microporous distributor 3, and then enter the interior of microporous distributor 3 for secondary mixing. After mixing, the mixture is sprayed into the solid acid catalyst bed in the fluidized bed reactor body 5.

[0027] Esterification reaction: N2 is introduced into the reactor through the top N2 inlet pipe and pressure regulating valve 16 to maintain a pressure of 0.8 MPa, so as to liquefy the olefins; the reaction temperature is controlled at 80℃; the catalyst baffle 4 is horizontally set in the middle of the bed to ensure uniform fluidization of the catalyst and full contact between the raw materials and the catalyst to carry out the esterification reaction.

[0028] Catalyst regeneration and circulation: The deactivated catalyst, reaction liquid, and sulfuric acid mixture collected from the middle of the fluidized bed reactor body 5 enter the reaction liquid hydrocyclone 8, and the separated liquid is returned to the upper part of the reactor; the solid catalyst and sulfuric acid enter the activation reactor 9, and 50°C hot water is introduced through the jacket gap, entering through the hot medium inlet 20 and exiting through the hot medium outlet 21. After activation treatment for 1.5 hours, it is sent to the sulfuric acid hydrocyclone 10; 95% of the separated sulfuric acid is returned to the sulfuric acid storage tank 11 through the sulfuric acid transfer pump 12 and the one-way valve 13, and 5% is discharged through the sulfuric acid discharge port; the solid catalyst is mixed with fresh acetic acid introduced through the flushing acetic acid inlet 17 and then returned to the fluidized bed reactor body 5 for recycling through the solid-liquid mixing transfer pump 14.

[0029] Sulfuric acid concentration maintenance: The concentration monitor 15 on the sulfuric acid storage tank 11 monitors the sulfuric acid concentration in real time. When the concentration is lower than the set value (5%), the replenishment valve of the sulfuric acid replenishment port is automatically opened to replenish fresh sulfuric acid and maintain the concentration at 5%±0.3%.

[0030] Reaction liquid circulation: The reaction liquid from the primary reactor enters the reaction liquid buffer tank 6 through the reaction liquid outlet, and is then sent to the preheater to 85°C by the reaction liquid transfer pump 7 before being sent to the secondary reactor to continue the reaction; 50% of the reaction liquid from the secondary reactor is returned to the primary reactor and 50% is sent to the post-treatment system.

[0031] After 72 hours of continuous industrial testing, the reactor in this embodiment achieved an olefin conversion rate of 94.2%, a product purity of 99.3%, and a catalyst activity retention rate of over 90% after 30 days of continuous operation. The pressure fluctuation was ≤ ±0.02 MPa, and all indicators were superior to those of traditional reactors.

[0032] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A multi-stage fluidized bed reactor for olefin esterification, characterized in that, The system comprises at least two series-connected fluidized bed reactor units. Each fluidized bed reactor unit includes a fluidized bed reactor body, an olefin delivery pipeline connected to the bottom of the fluidized bed reactor body, an acetic acid delivery pipeline connected to the bottom of the fluidized bed reactor body, an acetic acid distributor located within the fluidized bed reactor body and connected to the acetic acid delivery pipeline, an input pipeline connected to the top of the fluidized bed reactor body, a solid acid catalyst bed located in the middle of the fluidized bed reactor body, a deactivated catalyst extraction pipeline connected to the middle of the fluidized bed reactor body, and a deactivated catalyst extraction pipeline connected to the top of the fluidized bed reactor body. A hydrocyclone separator for the reaction liquid is connected to the outlet pipeline of the chemical agent. The liquid phase outlet of the hydrocyclone separator is connected to the upper part of the fluidized bed reactor body. The solid phase outlet of the hydrocyclone separator is connected to an activation reactor. A jacket is provided outside the activation reactor. A hot fluid medium flows through the jacket. The activation reactor is connected to a sulfuric acid hydrocyclone separator. The liquid phase outlet of the sulfuric acid hydrocyclone separator is connected to a sulfuric acid storage tank. The solid phase outlet of the sulfuric acid hydrocyclone separator is connected to the fluidized bed reactor body through a reflux channel equipped with a solid-liquid mixing and conveying pump. A flushing acetic acid inlet is connected to the reflux channel. The reaction liquid outlet of the fluidized bed reactor body is connected to a reaction liquid buffer tank. The reaction liquid buffer tank of the first-stage fluidized bed reactor body is connected to the olefin delivery pipeline of the second-stage fluidized bed reactor body through a delivery pipeline. The reaction liquid buffer tank of the final-stage fluidized bed reactor body is connected to the acetic acid delivery pipeline of the first-stage fluidized bed reactor body through a return pipeline. A reaction liquid delivery pump and a preheater are installed on the delivery pipeline.

2. The multi-stage fluidized bed reactor for olefin esterification as described in claim 1, characterized in that: The acetic acid distributor is equipped with microporous distributors on both the upper and lower sides.

3. A multi-stage fluidized bed reactor for olefin esterification as described in claim 1, characterized in that: A heater is installed on the acetic acid delivery pipeline.

4. A multi-stage fluidized bed reactor for olefin esterification as described in claim 1, characterized in that: The jacket is provided with a heat medium inlet and a heat medium outlet.

5. A multi-stage fluidized bed reactor for olefin esterification as described in claim 4, characterized in that: The heat medium is at least one of hot steam, heat transfer oil, and hot water.

6. A multi-stage fluidized bed reactor for olefin esterification as described in claim 1, characterized in that: A pressure regulating valve is installed on the input pipeline.

7. A multi-stage fluidized bed reactor for olefin esterification as described in claim 1, characterized in that: A catalyst baffle is provided above the solid acid catalyst bed.

8. A multi-stage fluidized bed reactor for olefin esterification as described in claim 1, characterized in that: The sulfuric acid storage tank is equipped with a concentration monitor and is connected to a sulfuric acid supply port.

9. A multi-stage fluidized bed reactor for olefin esterification as described in claim 1, characterized in that: The sulfuric acid storage tank is connected to the activation reactor via a circulation pipeline, which is equipped with a sulfuric acid transfer pump and a one-way valve.

10. A multi-stage fluidized bed reactor for olefin esterification as described in claim 1, characterized in that: The sulfuric acid hydrocyclone separator is connected to the sulfuric acid storage tank via a connecting pipe with a sulfuric acid discharge port.

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