Exchange feed unit and reaction rectification column using the same

Abstract

This invention discloses a catalyst replacement and feeding unit and a reactive distillation column using this unit. The catalyst replacement and feeding unit includes: a catalyst downcomer, which is disposed between the current tray and the lower mass transfer reaction space in the reactive distillation column. The catalyst downcomer is equipped with a removable discharge chamber, which is used to retain solid particles of the catalyst and allow the liquid phase to enter the lower mass transfer reaction space through the catalyst downcomer when the catalyst on the current tray needs to be replaced; and a downcomer, which is disposed at a corresponding position of the catalyst downcomer. The downcomer is equipped with a loading port. When the current catalyst downcomer is closed, the loading port of the upper downcomer is used to load fresh catalyst. The fresh catalyst is carried by the upper liquid phase and enters the current mass transfer reaction space through the downcomer. This invention enables online replacement of the catalyst during the gas-liquid-solid reaction process through the catalyst replacement unit, which is convenient and efficient.

Description

Technical Field

[0001] This invention relates to the field of petrochemical technology, and in particular to a fuel exchange and feeding unit and a reactive distillation column using the unit. Background Technology

[0002] A reactive distillation column is a gas-liquid mass transfer device that combines reaction and distillation processes. Reactive distillation technology is widely used in etherification, esterification, and alkylation reactions. Compared to traditional processes that use reactors and distillation columns independently, the use of reactive distillation columns can significantly reduce operating and investment costs. Reactive distillation columns can be plate columns or packed columns. Plate columns are widely used due to their simple structure and high adaptability.

[0003] Traditional reactive distillation technology uses homogeneous catalysts, which suffer from difficulties in separating them from the reaction products. Furthermore, most homogeneous catalysts are acidic or basic, causing severe corrosion to the equipment. In recent years, the use of heterogeneous catalysts has significantly improved the solutions to equipment corrosion and catalyst separation problems. The replacement and loading methods of heterogeneous catalysts are currently a key research direction in reactive distillation technology. To ensure that the reaction products meet quality requirements, the catalyst in the column needs to be replaced periodically. Catalyst replacement can be done online or during shutdown. Shutdown replacement of the catalyst leads to frequent start-ups and shutdowns of the production unit, and this method is being phased out.

[0004] Chinese patent CN108043061 discloses a reactive distillation column with online catalyst replacement. It disperses a solid catalyst on trays and installs a filter screen on the downcomer to prevent catalyst loss to lower trays. Online replacement of the solid catalyst is achieved through online replacement pipelines around the column. However, this reactive distillation column suffers from problems such as easy catalyst accumulation, easy filter clogging, and uneven gas-liquid-solid three-phase contact. Furthermore, an additional pump is required for catalyst replacement, resulting in high operating costs.

[0005] Therefore, there is an urgent need for a reactive distillation device that can achieve efficient and convenient online catalyst replacement, thereby overcoming the above-mentioned defects in the existing technology.

[0006] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to provide a catalyst replacement and feeding unit and a reactive distillation column using the unit. The catalyst can be replaced online during the gas-liquid-solid reaction process through the catalyst replacement and feeding unit. The replacement is convenient and efficient.

[0008] To achieve the above objectives, according to a first aspect of the present invention, a catalyst replacement and feeding unit is provided, applied in a gas-liquid-solid reactive distillation column, comprising: a catalyst replacement downcomer disposed between the current tray and the lower mass transfer reaction space in the reactive distillation column, the catalyst replacement downcomer being provided with a detachable discharge bin, the discharge bin being used to retain solid particles of the catalyst and allow the liquid phase to enter the lower mass transfer reaction space through the catalyst replacement downcomer when the catalyst on the current tray needs to be replaced; and a downcomer feed pipe disposed at a corresponding position of the catalyst replacement downcomer, the downcomer feed pipe being provided with a loading port, the loading port of the upper downcomer feed pipe being used to fill fresh catalyst when the catalyst replacement downcomer of the current tray is in a closed state, the fresh catalyst being carried by the upper liquid phase and entering the current mass transfer reaction space through the downcomer feed pipe.

[0009] Furthermore, in the above technical solution, the unloading hopper is disassembled and installed via detachable flanges installed on the pipelines at both ends.

[0010] Furthermore, in the above technical solution, a first switching valve is provided at the upper part of the catalyst replacement downcomer. When it is necessary to replace the catalyst in this layer, the first switching valve is in the open state, and the catalyst solid particles flow into the unloading chamber along with the liquid phase through the catalyst replacement downcomer. After all the catalyst to be replaced has entered the unloading chamber, the first switching valve is in the closed state.

[0011] Furthermore, in the above technical solution, a first filter screen is provided on the lower end pipeline of the unloading hopper to trap solid catalyst particles and allow the liquid phase to pass through.

[0012] Furthermore, in the above technical solution, a second switch valve is provided at the upper part of the downcomer pipe. When all the catalyst to be replaced in this layer enters the unloading hopper, the second switch valve of the upper downcomer pipe is in the open state.

[0013] Furthermore, in the above technical solution, a second filter screen is provided at the upper end of the liquid replenishment pipe to trap solid catalyst particles while allowing the liquid phase to pass through.

[0014] According to a second aspect of the present invention, a reactive distillation column is provided, comprising the refrigerant feeding unit of any of the preceding claims.

[0015] Furthermore, in the above technical solution, there are one or more downcomer pipes and downcomer replenishment pipes in the downcomer replenishment unit. When there are multiple downcomer pipes and downcomer replenishment pipes, their numbers are equivalent.

[0016] Furthermore, in the above technical solution, the downcomer and the replenishing downcomer are arranged symmetrically with respect to the central axis of the reactive distillation column.

[0017] Furthermore, in the above technical solution, the surface of the trays in the reactive distillation column can be inclined, with the inclination direction being from the column wall towards the inlet of the refrigerant downcomer. The inclination angle can be 5–10°.

[0018] Furthermore, in the above technical solution, a riser pipe is provided in the space where the agent replacement and feeding unit is set up. The riser pipe extends along the central axis of the reactive distillation column. A gas distributor is provided at the upper end of the riser pipe, below the liquid surface of the mass transfer reaction space. The gas phase is ejected through the gas distributor through the uniformly distributed gas holes and mixes with the liquid phase to form bubbles.

[0019] Furthermore, in the above technical solution, the gas distributor can be arranged in a star-shaped pattern, and the air holes can be set on the upper and lower surfaces of the star-shaped distributor.

[0020] Furthermore, in the above technical solution, an ultrasonic element can be installed below the liquid surface in the mass transfer reaction space. This ultrasonic element is connected to a controller outside the tower via a lead wire. It is used to enhance the mixing of the gas, liquid, and solid phases through the cavitation effect generated by ultrasonic waves in the liquid phase, and to avoid the formation of catalyst residue on the tower plate by agitating the liquid phase when the catalyst needs to be replaced.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1) This invention enables convenient online replacement of solid catalyst particles on each tray of a reactive distillation column by installing a downcomer and a replenishing downcomer between the current tray and the lower reaction mass transfer space. When the solid catalyst to be replaced in this tray enters the unloading bin, the downcomer is closed and the unloading bin is disassembled. At this time, the liquid phase of the upper tray can carry the fresh catalyst entering from the charging port into the current tray through the replenishing downcomer, thus allowing the solid catalyst particles of each tray to be replaced without shutting down the system.

[0023] 2) The present invention enables the gas phase to enter the liquid phase more uniformly through the riser pipe and the star-shaped gas distributor at the end of the riser pipe. The gas phase and liquid phase are mixed by bubbling through jetting, which creates a certain stirring effect on the liquid phase. This allows the solid catalyst to be suspended below the liquid surface in the reaction mass transfer space of each layer, which is more conducive to the mixing and mass transfer of the gas-liquid-solid three phases.

[0024] 3) By setting the trays to an inclined state, this invention makes it easier for the liquid phase carrying the catalyst to be replaced to flow into the catalyst downcomer when replacing the solid catalyst.

[0025] 4) The ultrasonic element below the liquid surface of the present invention can, on the one hand, further enhance the mixing of the gas-liquid-solid three phases through the cavitation effect generated by the ultrasonic waves in the liquid phase, and on the other hand, make it easier for the solid catalyst particles to be suspended by stirring the liquid phase when the catalyst needs to be replaced, so as to minimize the formation of catalyst residue on the tray. At the same time, it can also enhance the filtration effect and prevent the filter screen set on the liquid replenishment pipe from being blocked by solid particles.

[0026] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, and to make the above and other objects, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. Attached Figure Description

[0027] Figure 1 This is a cross-sectional structural schematic diagram of the reactive distillation column according to the present invention.

[0028] Figure 2 This is a top view of the mass transfer reaction space above the trays of the reactive distillation column according to the present invention (showing the gas distributor, ultrasonic element, downcomer and downcomer replenishment pipe).

[0029] Explanation of key figure labels:

[0030] 1-Reactive distillation column, 10-Training plate, 11-Mass transfer reaction space, 2-Reagent downcomer, 20-Unloading bin, 21-First switching valve, 22-Removable flange, 23-First filter screen, 3-Downcomer replenishment pipe, 31-Second switching valve, 32-Second filter screen, 33-Catalyst charging port, 4-Gas riser, 40-Gas distributor, 401-Vacuum vent, 5-Ultrasonic element, 51-Lead wire, 52-Controller. Detailed Implementation

[0031] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0032] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0033] In this document, for ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “above,” “upper,” etc., are used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that spatial relative terms are intended to encompass different orientations of an object in use or operation, in addition to those depicted in the figures. For example, if an object in the figure is flipped, an element described as “below” or “under” another element or feature would be oriented “above” that element or feature. Thus, the exemplary term “below” can encompass both the downward and upward orientations. An object may also have other orientations (rotated 90 degrees or other orientations), and the spatial relative terms used herein should be interpreted accordingly.

[0034] In this document, the terms "first," "second," etc., are used to distinguish two different elements or parts, and are not used to define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," etc., can also be used interchangeably.

[0035] The refrigerant replenishment unit and the reactive distillation column using this unit are suitable for gas-liquid-solid reactions. In the reactive distillation column, the gas and liquid phases react simultaneously in the mass transfer reaction space under the action of a solid catalyst, while also undergoing gas-liquid mass transfer separation. The gas phase can be uniformly injected into the mass transfer reaction space of the current tray via a riser and gas distributor, while the liquid phase descends to the mass transfer reaction space of the next tray via a downcomer. This invention enhances the contact effect of the gas-liquid-solid three-phase mixing in the mass transfer reaction space of the reactive distillation column. The refrigerant replenishment unit of this invention also enables efficient and convenient online replacement of the solid catalyst (granules).

[0036] Example 1

[0037] like Figure 1 As shown, this embodiment provides a catalyst replacement and replenishment unit applied in a gas-liquid-solid reactive distillation column, comprising: a catalyst replacement downcomer 2 and a downcomer replenishment pipe 3 disposed between the current tray and the lower mass transfer reaction space. The catalyst replacement downcomer 2 is equipped with a detachable discharge chamber 20, which, when the catalyst on the current tray 10 needs to be replaced, traps solid particles of the catalyst and allows the liquid phase to enter the lower mass transfer reaction space 11 through the catalyst replacement downcomer 2. The downcomer replenishment pipe 3 is disposed at a corresponding position on the catalyst replacement downcomer 2 and is equipped with a catalyst loading port 33. When the current catalyst replacement downcomer 2 is closed, the catalyst loading port 33 of the upper downcomer replenishment pipe 3 is used to load fresh catalyst, which can be carried by the upper liquid phase and enter the current mass transfer reaction space 11 through the downcomer replenishment pipe 3.

[0038] Further as Figure 1As shown, specifically, the number of trays can be 3 to 80, and the tray shape can be circular or square, preferably circular, with a tray diameter of 500 to 3000 mm. The height of the downcomer 2 and the replenishment downcomer 3 can be set to 500 to 3000 mm. The upper ends of the downcomer 2 and the replenishment downcomer 3 are connected to the tray 10 of the same layer, and the lower ends are connected to the upper end of the mass transfer reaction space 11 of the lower layer, with a height of 800 to 3000 mm. The volume of the unloading bin 20 is determined according to the amount of catalyst on each tray, ensuring that when all the catalyst on each tray is unloaded into the unloading bin 20, there is still 0.2 to 0.5 times the volume of remaining space inside the unloading bin 20.

[0039] Further as Figure 1 As shown, preferably but not limitingly, the unloading hopper 20 is installed on the pipeline of the catalyst replacement downcomer 2, and can be disassembled and installed through detachable flanges 22 installed at both ends of the pipeline of the unloading hopper 20. Further, a first switching valve 21 is provided at the upper part of the catalyst replacement downcomer 2. When it is necessary to replace the solid catalyst in this layer, the first switching valve 21 is in the open state, and the solid catalyst particles can flow into the unloading hopper 20 along with the liquid phase through the catalyst replacement downcomer 2; when all the catalyst to be replaced has entered the unloading hopper 20, the first switching valve 21 is in the closed state, at which time the liquid phase in the upper layer can flow into this layer through the upper downcomer replenishment pipe 3. Further as... Figure 1 As shown, a first filter screen 23 is installed on the lower end pipeline of the unloading hopper 20. The first filter screen 23 is used to trap solid catalyst particles and allow liquid phase to pass through. That is, the solid catalyst particles to be replaced are trapped in the unloading hopper 20, while the liquid phase can enter the lower mass transfer reaction space 11 through the first filter screen 23. After the first switch valve 21 is closed, the unloading hopper 20 can be disassembled and the catalyst particles to be replaced can be removed, and then it can be reinstalled in its original position. During the disassembly process, the liquid phase on the upper tray continues to enter the tray. During this process, liquid can be replenished through the upper downcomer pipe 3 while fresh catalyst is loaded into the catalyst loading port 33.

[0040] Further as Figure 1 As shown, a second switching valve 31 is provided at the upper part of the downcomer pipe 3. After all the catalyst to be replaced in this layer enters the unloading chamber 20 through the downcomer pipe 2, the second switching valve 31 of the upper downcomer pipe 3 is opened to allow fresh catalyst to be loaded into the downcomer pipe 3. The fresh catalyst is carried by the liquid phase into the mass transfer reaction space 11 of this layer. Furthermore, a second filter screen 32 is provided at the upper end of the downcomer pipe 3 to trap solid catalyst particles while allowing the liquid phase to pass through.

[0041] In this embodiment, by installing a downcomer and a replenishment downcomer between the current tray and the lower reaction mass transfer space, the solid catalyst particles on each tray of the reactive distillation column can be conveniently replaced online. When the solid catalyst to be replaced in this tray enters the unloading hopper, the downcomer is closed and the unloading hopper is disassembled. At this time, the liquid phase of the upper tray can carry the fresh catalyst entering from the charging port into the current tray through the replenishment downcomer, thus allowing the solid catalyst particles of each tray to be replaced without shutting down the system.

[0042] Example 2

[0043] This embodiment provides a reactive distillation column 1, in which a refrigerant feeding unit as described in Embodiment 1 is provided at the corresponding position of each tray.

[0044] In the reactive distillation column 1, a riser pipe 4 is provided in the space where the refrigerant feeding unit is located. The riser pipe 4 extends along the central axis of the reactive distillation column 1. A gas distributor 40 is provided at the upper end of the riser pipe 4, below the liquid surface of the mass transfer reaction space 11. The gas phase is ejected through uniformly distributed gas holes 401 on the gas distributor 40 and mixes with the liquid phase in a bubbling manner. Further as... Figure 2 As shown, preferably but not limitingly, the gas distributor 40 is arranged in a star-shaped pattern, and the gas holes 401 are provided on the upper and lower surfaces of the star-shaped distributor (see reference). Figure 1 (Gas ejection state). The length of the "X"-shaped branch pipe of the gas distributor 40 is 0.25 to 0.45D (D is the inner diameter of the tower), and the diameter of the branch pipe ranges from DN25 to DN150. Each branch pipe of the gas distributor 40 has evenly distributed vents 401 on its upper and lower surfaces. The distance between adjacent vents is 0.2 to 0.4L (L is the length of the branch pipe). The vents are circular holes with a diameter range of 0.5 to 10 mm. The height of the center of the branch pipe of the gas distributor 40 from the tower plate is 300 to 1000 mm.

[0045] Specifically, the ratio of the diameter of the riser pipe 4 to the inner diameter of the column ranges from 0.1 to 0.4, the ratio of the diameter of the downcomer pipe 3 to the inner diameter of the column ranges from 0.05 to 0.4, and the ratio of the diameter of the downcomer pipe 2 to the inner diameter of the column ranges from 0.05 to 0.4. The distance between the center of the downcomer pipe and the center of the tray ranges from 0.15 to 0.35D (D is the inner diameter of the column), and the distance between the center of the downcomer pipe and the center of the tray ranges from 0.15 to 0.35D. The riser pipe 4 is located at the geometric center of each tray. When only one downcomer pipe 2 and one downcomer pipe 3 are used, they can be symmetrically arranged on both sides of the tray and symmetrically set with respect to the central axis of the reactive distillation column (see reference). Figure 2 When multiple downcomer pipes 2 and downcomer replenishment pipes 3 are used, the number of both should be equal, and the circumferential spacing should be set evenly (not shown in the figure).

[0046] Further as Figure 1 As shown, preferably but not limitingly, the surface of the tray 10 of the reactive distillation column 1 is inclined, with the inclination direction from the column wall towards the inlet of the downcomer 2. This design allows the liquid phase carrying the catalyst to be replaced to more easily flow into the downcomer 2 during solid catalyst replacement. The bubbling action of the gas phase not only increases gas-liquid mass transfer but also agitates the liquid phase, suspending the solid catalyst and facilitating its flow into the downcomer 2, thus preventing catalyst residue on the tray. Furthermore, the inclination angle of the tray can be designed to be 5–10°.

[0047] Further as Figure 2 As shown, preferably but not limitingly, an ultrasonic element 5 may also be provided below the liquid surface in the mass transfer reaction space 11. The ultrasonic element 5 is connected to a controller 52 outside the tower via a lead wire 51. Specifically, when the inner diameter of the tower D ≤ 1000 mm, one ultrasonic element 5 can be installed, located near the downcomer pipe 3, with the ultrasonic element 5 positioned 0.2–0.4D from the center of the tower plate; when the inner diameter of the tower 1000 mm ≤ D ≤ 3000 mm, two or four ultrasonic elements 5 can be installed (see reference). Figure 2 The ultrasonic element 5 is arranged symmetrically about the center of the tray below the liquid surface in the mass transfer reaction space. The ultrasonic element 5 can be a cylindrical structure made of stainless steel. A stainless steel pipeline is connected to the side of the ultrasonic element near the tower wall, and a lead wire 51 is arranged inside the pipeline, connecting to a controller 52 outside the tower. The cavitation effect generated by the ultrasound in the liquid phase enhances the mixing of the gas, liquid, and solid phases, and when the catalyst needs to be replaced, the agitation of the liquid phase prevents catalyst residue from forming on the tray.

[0048] This embodiment utilizes a riser pipe and a star-shaped gas distributor at the end of the riser pipe to ensure more uniform gas-liquid phase entry into the liquid phase. The jetting gas and liquid phases form bubbles, creating a stirring effect on the liquid phase. This allows the solid catalyst to remain suspended below the liquid surface in each reaction mass transfer space, facilitating the mixing and mass transfer of the gas-liquid-solid three phases. The inclined arrangement of the trays makes it easier for the liquid phase carrying the catalyst to be replaced to flow into the downcomer when replacing the solid catalyst. The placement of the ultrasonic element below the liquid surface further enhances the mixing of the gas-liquid-solid three phases through cavitation generated by ultrasound in the liquid phase. Furthermore, when catalyst replacement is needed, the agitation of the liquid phase helps to keep the solid catalyst particles in suspension, minimizing catalyst residue on the trays. It also enhances filtration, preventing the filter screen on the downcomer from being clogged by solid particles.

[0049] The following is a detailed explanation using a specific example (i.e., the process of preparing butyl acetate by reacting n-butanol and methyl acetate with each other).

[0050] The diameter of the tray 10 is set to 1800 mm, the height of the mass transfer reaction space 11 is set to 800 mm, the diameter of the riser pipe 4 is 200 mm, and the diameter of the downcomer pipe 2 and the downcomer pipe 3 are both 150 mm and the height is 1100 mm.

[0051] The branch pipe of the gas distributor 40 is a DN50 round pipe with a length of 700mm. The air hole 401 is a round hole with a diameter of 10mm, and the spacing between adjacent air holes is designed to be 150mm.

[0052] Two ultrasonic elements 5 are symmetrically arranged on each tray, with a horizontal distance of 650 mm from the center of the tray. Under the control of the controller 52, the ultrasonic elements generate ultrasonic waves with a frequency of 46 kHz and a power of 50 W.

[0053] The catalyst loading port 33 on the downcomer pipe 3 adopts a flange-type handhole mechanism with a size of DN100. The unloading hopper 20 on the downcomer pipe 2 adopts a cylindrical structure with a diameter of DN500 and a height of 400mm.

[0054] During normal operation, the first switch valve 21 of the downcomer 2 is closed, and the second switch valve 31 of the downcomer 3 is opened, allowing the liquid on the tray to flow into the lower mass transfer reaction space through the downcomer 3. The top operating temperature is 76℃, and the top operating pressure is 0.25 MPaG. Methyl acetate (liquid phase) enters the reactive distillation column from the top at a flow rate of 150 kg / h, and n-butanol (gas phase) enters the reactive distillation column from the bottom at a flow rate of 300 kg / h. The operating reflux ratio is 11. Under stable operation, the single-pass conversion rate of methyl acetate using the reactive distillation column of this invention can reach 63.5%.

[0055] The solid catalyst needs to be replaced every 4 months. The specific operating steps are as follows:

[0056] Unloading the old catalyst: First, close the second switch valve 31 and open the first switch valve 21 to allow the liquid phase to flow into the catalyst downcomer 2. The solid catalyst particles suspended in the liquid phase will then flow along with it. Once all the old catalyst on the tray has entered the unloading hopper 20, close the first switch valve 21 and open the second switch valve 31 on the downcomer 3 of this layer. Unload the old catalyst from the unloading hopper 20 by disassembling the flange, and then reinstall the unloading hopper.

[0057] Adding new catalyst: Open the catalyst loading port 33 on the upper liquid replenishment pipe 3 of the mass transfer reaction space where the old catalyst tray is located, and load the new catalyst from the loading port and let it go to the lower mass transfer reaction space along with the liquid phase in the pipe.

[0058] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. Any simple modifications, equivalent changes, and alterations made to the foregoing exemplary embodiments should fall within the scope of protection of the present invention.

Claims

1. A refill unit, characterized in that, Applications include gas-liquid-solid reactive distillation columns, including: A catalyst downcomer is installed between the current tray and the lower mass transfer reaction space in the reactive distillation column. The catalyst downcomer is equipped with a detachable discharge bin. When it is necessary to replace the catalyst on the current tray, the discharge bin is used to retain the solid particles of the catalyst and allow the liquid phase to enter the lower mass transfer reaction space through the catalyst downcomer. A downcomer tube is installed at a corresponding position of the downcomer tube. The downcomer tube is provided with a loading port. When the downcomer tube in this layer is in the closed state, the loading port of the downcomer tube in the upper layer is used to fill fresh catalyst. The fresh catalyst is carried by the upper liquid phase and enters the mass transfer reaction space of this layer through the downcomer tube.

2. The refill unit according to claim 1, characterized in that, The unloading hopper can be disassembled and installed via detachable flanges installed on the pipelines at both ends.

3. The refill unit according to claim 1, characterized in that, The upper part of the catalyst replacement downcomer is equipped with a first switch valve. When it is necessary to replace the catalyst in this layer, the first switch valve is in the open state, and the catalyst solid particles flow into the unloading chamber along with the liquid phase through the catalyst replacement downcomer. When all the catalyst to be replaced has entered the unloading chamber, the first switch valve is in the closed state.

4. The refill unit according to claim 3, characterized in that, A first filter screen is installed on the lower end pipeline of the unloading hopper to trap the solid particles of the catalyst while allowing the liquid phase to pass through.

5. The refill unit according to claim 1, characterized in that, The upper part of the liquid replenishment pipe is equipped with a second switch valve. When all the catalyst to be replaced in this layer enters the unloading hopper, the second switch valve of the upper liquid replenishment pipe is in the open state.

6. The refill unit according to claim 5, characterized in that, The upper end of the liquid replenishment pipe is equipped with a second filter screen, which is used to trap the solid particles of the catalyst and allow the liquid phase to pass through.

7. A reactive distillation column, characterized in that, Includes the refill unit as described in any one of claims 1 to 6.

8. The reactive distillation column according to claim 7, characterized in that, The replacement and replenishment unit contains one or more replacement downcomers and downcomer replenishment pipes. When there are multiple replacement downcomers and downcomer replenishment pipes, their numbers are roughly equal.

9. The reactive distillation column according to claim 8, characterized in that, When there are multiple downcomers and replenishment downcomers, they are arranged symmetrically with respect to the central axis of the reactive distillation column.

10. The reactive distillation column according to claim 7, characterized in that, The surface of the trays in the reactive distillation column is inclined, with the inclination direction being from the column wall toward the inlet of the refrigerant downcomer.

11. The reactive distillation column according to claim 10, characterized in that, The tilt angle is 5 to 10°.

12. The reactive distillation column according to claim 7, characterized in that, A riser pipe is provided in the space where the refrigerant feeding unit is set up. The riser pipe extends along the central axis of the reactive distillation column. A gas distributor is provided at the upper end of the riser pipe, below the liquid surface of the mass transfer reaction space. The gas phase is ejected through the gas distributor through the uniformly distributed gas holes and mixes with the liquid phase to form bubbles.

13. The reactive distillation column according to claim 12, characterized in that, The gas distributor is arranged in a star-shaped pattern, with air vents located on the upper and lower surfaces of the star-shaped distributor.

14. The reactive distillation column according to claim 12, characterized in that, An ultrasonic element is installed below the liquid surface in the mass transfer reaction space. The ultrasonic element is connected to a controller outside the tower via a lead wire. It is used to enhance the mixing of the gas, liquid and solid phases through the cavitation effect generated by the ultrasonic waves in the liquid phase, and to avoid the formation of catalyst residue on the tower plate by agitating the liquid phase when the catalyst needs to be replaced.

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