Catalytic reaction rectification unit, apparatus and method

Abstract

This invention discloses a catalytic reactive distillation unit, apparatus, and method. The catalytic reactive distillation unit includes: a reaction mass transfer channel, the upper end of which receives low-temperature liquid-phase reactants flowing downwards, and the lower end of which receives high-temperature gas phase flowing upwards; the reaction mass transfer channel contains a catalyst layer and a packing layer, with the catalyst layer positioned above the packing layer, and a first space between them; and a rising gas bypass, located outside the reaction mass transfer channel and connected to the first space. The liquid-phase products after the catalytic reaction merge with the high-temperature gas phase in the packing layer and undergo gas-liquid mass transfer. The rising gas phase after mass transfer carries the light components from the liquid-phase products into the rising gas bypass, completing mass transfer separation. This invention, through the setting of the rising gas bypass, not only increases the gas phase flow rate and effectively reduces the pressure drop within the reaction mass transfer channel, but also effectively solves the space occupation problem of the equipment. This invention can clean the blockage of the catalyst filter without additional power and can realize online replacement of the catalyst and / or packing.

Description

Technical Field

[0001] This invention relates to the field of petrochemical technology, and in particular to a catalytic reactive distillation unit, equipment, and method. Background Technology

[0002] Catalytic reactive distillation equipment is a gas-liquid mass transfer device that integrates reaction and distillation processes. Catalytic distillation technology has wide applications in etherification, esterification, and alkylation reactions. Compared to traditional processes that use separate reactors and distillation columns, the use of catalytic reactive distillation equipment can significantly reduce operating and investment costs.

[0003] In existing catalytic reactive distillation equipment, the catalytic reaction section and the mass transfer separation section are generally arranged alternately. This vertical arrangement results in a large space requirement. For example, Chinese patent application CN102824752A discloses a catalytic distillation column, including a column body, a catalytic reaction section, and a separation section, with the catalytic reaction section and separation section arranged alternately within the column body. In this design, the catalyst can be completely immersed in the reaction liquid, avoiding gas phase erosion and changes in the catalyst surface's wetness and dryness, thus extending the catalyst's lifespan.

[0004] In addition, preventing clogging and online replacement of heterogeneous catalysts are currently major concerns in the industry. Heterogeneous catalysts are solid particles with a certain volume, which are very prone to clogging the internal components of the column, thus affecting the normal operation of the equipment. Therefore, solving the clogging problem and minimizing its occurrence is of great significance. After a period of use, the activity and selectivity of the catalyst will decrease to some extent. In order to ensure that the reaction products meet the quality requirements, the catalyst in the column needs to be replaced regularly. Catalyst replacement during shutdowns leads to frequent start-ups and shutdowns of the production unit, resulting in poor economic efficiency, and has been gradually phased out.

[0005] Therefore, there is an urgent need for a catalytic reaction distillation device that can save space while meeting the requirements of reaction and distillation, and can also effectively solve the problems of catalyst blockage and online replacement.

[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 catalytic reactive distillation unit, equipment, and method. By setting up a gas-rising bypass, not only can the flow rate of the gas phase be increased and the pressure drop in the reaction mass transfer channel be effectively reduced, but the space occupied by the equipment can also be effectively solved.

[0008] Another objective of this invention is that, through the special structural design of the overflow pipe in the riser bypass, not only can the liquid phase be introduced into the riser bypass and bypass the blocked parts, but the gas phase pressure increased in the space below the catalyst layer can also be used to clear the blockage of the catalyst filter.

[0009] Another object of the present invention is to provide a catalytic reactive distillation apparatus in which the catalyst and / or packing can be replaced online.

[0010] To achieve the above objectives, according to a first aspect of the present invention, a catalytic reactive distillation unit is provided, comprising: a reaction mass transfer channel, wherein the upper end receives a low-temperature liquid-phase reactant flowing downwards, and the lower end receives a high-temperature gas phase flowing upwards; the reaction mass transfer channel is provided with a catalyst layer and a packing layer, wherein the catalyst layer is disposed above the packing layer, and a first space exists between the two; and a rising gas bypass, which is located outside the reaction mass transfer channel and communicates with the first space, wherein the liquid-phase product after the catalytic reaction merges with the high-temperature gas phase in the packing layer and undergoes gas-liquid mass transfer, and the rising gas phase after mass transfer carries the light components in the liquid-phase product into the rising gas bypass to complete mass transfer separation.

[0011] Furthermore, in the above technical solution, a clearing mechanism is provided at the corresponding position in the catalyst layer within the gas riser bypass. When the descending liquid phase is obstructed in the catalyst layer, the gas phase pressure in the first space is used to clear the filter screen of the catalyst layer.

[0012] Furthermore, in the above technical solution, the unblocking mechanism may include: an overflow pipe, the upper end of which is connected to the overflow inlet located above the catalyst layer in the reaction mass transfer channel, and the lower end is a narrowing orifice; the overflow pipe is provided with a corrugated section, which is used to extend the overflow pipe downward after the overflowing liquid phase enters the overflow pipe and fills it; a sealing plate is provided at the lower part of the narrowing orifice, and an overflow outlet is opened on the sealing plate, which is directly opposite the narrowing orifice; when the overflow pipe extends downward to the sealing plate, the rising gas phase is blocked in the first space.

[0013] Furthermore, in the above technical solution, a first disassembly flange may be provided at both ends of the reaction mass transfer channel for disassembling and replacing the entire reaction mass transfer channel after the catalyst and / or packing fails.

[0014] Furthermore, in the above technical solution, the area from below the packing layer to the first disassembly flange position within the reaction mass transfer channel is a second space. The side wall of this second space is provided with a gas riser branch pipe for providing a high-temperature gas phase.

[0015] Furthermore, in the above technical solution, the rising gas branch pipe may include a vertical section and a bent section, the bent section extending obliquely downward from the top of the vertical section to the side wall of the reaction mass transfer channel and communicating with the second space.

[0016] A second disassembly flange is provided at the corresponding position of the first disassembly flange on the vertical section of the gas riser branch pipe and on the gas riser bypass.

[0017] According to a second aspect of the present invention, the present invention provides a catalytic reactive distillation apparatus, comprising the aforementioned catalytic reactive distillation unit, wherein multiple catalytic reactive distillation units are arranged laterally on each tray.

[0018] Furthermore, in the above technical solution, the upper end of the reaction mass transfer channel in each catalytic reactive distillation unit is connected to the liquid phase manifold, which receives liquid phase products from the upper tray.

[0019] Furthermore, in the above technical solution, the gas riser bypass in each catalytic reaction distillation unit is connected to the gas phase main pipe, and the gas riser branch pipe is connected to the gas phase main pipe of the lower tray.

[0020] According to a third aspect of the present invention, the present invention provides a catalytic reactive distillation method, which utilizes the aforementioned catalytic reactive distillation unit, wherein multiple catalytic reactive distillation units are arranged laterally on each tray; the method includes the following steps: A. Two or more low-temperature liquid-phase reactants enter the catalyst layer in the reaction mass transfer channel from top to bottom to carry out a catalytic reaction; B. The liquid-phase product after the catalytic reaction merges with the high-temperature gas phase from bottom to top in the packing layer of the reaction mass transfer channel to carry out gas-liquid mass transfer, and the rising gas phase after mass transfer carries the light components in the liquid-phase product into the rising gas bypass to complete the mass transfer separation.

[0021] Furthermore, in the above technical solution, when the catalytic reaction has been going on for a period of time and the filter screen of the catalyst layer becomes clogged, the liquid phase enters the overflow pipe set in the rising gas bypass through the overflow inlet; the overflow pipe extends downward to the sealing plate so that the liquid phase flows out through the overflow outlet and enters the first space in the reaction mass transfer channel, while the rising gas phase is blocked in the first space, and the gas pressure in the first space rises until the clogged filter screen is cleared.

[0022] Furthermore, in the above technical solution, when the catalytic reactive distillation equipment needs to replace the catalyst and / or packing after operating for a period of time, a certain catalytic reactive distillation unit is completely disassembled from the first disassembly flange and the second disassembly flange, while other catalytic reactive distillation units continue to operate normally, thus completing the online replacement of the catalyst and / or packing.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1) The catalytic reaction distillation unit of the present invention is provided with a gas riser bypass 2 for the upward flow of the gas phase after mass transfer. This not only increases the flow rate of the gas phase in the unit and effectively reduces the pressure drop in the reaction mass transfer channel, but also effectively reduces the space occupied by the equipment compared with the existing "reaction first, distillation later" scheme where the catalyst layer and packing layer are staggered.

[0025] 2) The present invention uses a retractable overflow pipe (i.e., a corrugated section is provided on the overflow pipe) in the rising gas bypass. Without the need for additional power, the overflow pipe can be extended downward by the pressure of the liquid phase alone. This not only allows the overflowing liquid phase to be guided into the bypass and bypass the blockage, but also blocks the rising gas phase and forms a short-term high-pressure state in the first space. The increased gas pressure is used to blow open the blocked catalyst filter and achieve the purpose of clearing the blockage.

[0026] 3) After the equipment of the present invention has been running for a period of time, when it is necessary to replace the catalyst and / or packing, the entire catalytic reaction distillation unit can be disassembled from the first disassembly flange and the second disassembly flange without affecting the normal operation of other catalytic reaction distillation units in the equipment;

[0027] 4) By designing the rising gas branch pipe as a combination of a vertical section and a bent section, the present invention can effectively prevent the descending liquid phase from flowing into the gas phase branch pipe without affecting the supply of rising gas phase. In addition, the existence of the second space can provide a buffer for the gas phase that is inclined downward from the bent section, so that it changes its running direction to vertically upward.

[0028] 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

[0029] Figure 1 This is a schematic diagram of the overall structure of the catalytic reactive distillation equipment of the present invention (the direction of the dashed arrows in the figure is the direction of the rising gas phase, and the direction of the solid arrows is the direction of the liquid phase).

[0030] Figure 2 This is a schematic diagram of the catalytic reactive distillation unit of the present invention (under normal operating conditions; the lower end of the overflow pipe adopts a conical design).

[0031] Figure 3 This is a schematic diagram of the catalytic reactive distillation unit of the present invention (with the catalyst filter screen clogged and the liquid level higher than the overflow inlet; the lower end of the overflow pipe adopts a planar design).

[0032] Explanation of key figure labels:

[0033] 100 - Catalytic reactive distillation equipment, 100A - Catalytic reactive distillation unit;

[0034] 1-Reaction mass transfer channel, 1A-First space, 1B-Second space, 11-Catalyst layer, 110-Catalyst, 111-Catalyst cover plate, 112-Filter screen, 113-Catalyst support grid, 12-Packing layer, 120-Packing, 121-Packing cover plate, 122-Packing support grid, 13-Overflow inlet, 2-Gas riser bypass, 21-Overflow pipe, 211-Corrugated section, 22-Sealing plate, 221-Overflow outlet, 3-Gas riser branch pipe, 31-Vertical section, 32-Bent section, 4-First disassembly flange, 5-Second disassembly flange, 6-Liquid phase main pipe, 7-Gas phase main pipe. Detailed Implementation

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] Example 1

[0040] like Figure 1 , 2As shown, this embodiment provides a catalytic reactive distillation unit 100A, including a reaction mass transfer channel 1 and a rising gas bypass 2. The upper end of the reaction mass transfer channel 1 receives low-temperature liquid-phase reactants (two or more reactants) flowing downwards, while the lower end receives high-temperature gas phase (which does not participate in the reaction but only performs gas-liquid mass transfer with the liquid phase) flowing upwards. The reaction mass transfer channel 1 contains a catalyst layer 11 and a packing layer 12, with the catalyst layer 11 positioned above the packing layer 12, and a first space 1A between them. The rising gas bypass 2 is located outside the reaction mass transfer channel 1 and communicates with the first space 1A. The liquid-phase products after the catalytic reaction (i.e., two or more liquid-phase products, including light and heavy components) merge with the high-temperature gas phase in the packing layer 12 and undergo gas-liquid mass transfer. The rising gas phase after mass transfer carries the light components from the liquid-phase products into the rising gas bypass 2, completing mass transfer separation (i.e., separating the light and heavy components from the liquid-phase products to complete the distillation process).

[0041] Further as Figure 1 , 2 As shown, in each catalytic reactive distillation unit 100A, under normal operating conditions, the gas phase passes sequentially from bottom to top through the packing layer 12 and the rising gas bypass 2, while the liquid phase passes sequentially from top to bottom through the catalyst layer 11 and the packing layer 12. The descending liquid phase (containing two or more reactants) reacts with the catalyst 110 on the catalyst layer 11, and the gas and liquid phases achieve mass transfer separation on the packing layer 12. The diameters of the catalyst layer 11 and the packing layer 12 are adapted to the inner diameter of the reaction mass transfer channel 1. In this embodiment, a cylindrical structure is adopted, further as shown below. Figure 2 As shown, the catalyst layer consists of a catalyst support grid 113, a filter screen 112, a solid catalyst 110, and a catalyst cover plate 111. The catalyst cover plate 111 has a hollow structure, allowing the liquid phase to pass through but preventing the catalyst particles from moving axially. The packing layer 12 consists of a packing support grid 122, packing 120, and a packing cover plate 121. The packing can be structured or loose packing.

[0042] The catalytic reaction distillation unit 100A of this embodiment is equipped with a gas riser bypass 2 for the upward flow of the gas phase after mass transfer. This not only increases the flow rate of the gas phase within the unit and effectively reduces the pressure drop in the reaction mass transfer channel 1, but also effectively reduces the space occupied by the equipment compared to the existing "reaction first, distillation later" scheme with alternating catalyst and packing layers.

[0043] Further as Figure 2 , 3 As shown, in this embodiment, a clearing mechanism is provided at the corresponding position of the catalyst layer 11 in the gas riser bypass 2. When the descending liquid phase is blocked in the catalyst layer 11, the increased gas phase pressure in the first space 1A between the catalyst layer 11 and the packing layer 12 is used to clear the blockage of the filter screen 112 of the catalyst layer 11.

[0044] Further, preferably but not limitingly, the unclogging mechanism may include an overflow pipe 21 and a sealing plate 22. The upper end of the overflow pipe 21 is connected to the overflow inlet 13 located above the catalyst layer 11 within the reaction mass transfer channel 1, and the lower end is a narrow-diameter inlet, meaning the outlet of the overflow pipe 21 is much smaller than its inner diameter. This ensures that the overflow pipe maintains a certain pressure after being filled with liquid phase, while the outlet forms a slow outflow or dripping state of the liquid phase. The overflow pipe 21 is provided with a corrugated section 211, which extends the overflow pipe downwards after the overflowing liquid phase enters and fills the overflow pipe. Since the overflow pipe 21 can maintain a certain pressure after being filled with liquid phase, the corrugations of the corrugated section 211 can expand and unfold under this pressure, thus increasing the overall length of the overflow pipe 21, i.e., the overflow pipe 21 extends downwards as a whole (see reference). Figure 3 The sealing plate 22 is located at the lower part of the reduced diameter port, and an overflow outlet 221 is provided on the sealing plate 22, which faces the reduced diameter port directly. When the overflow pipe 21 extends downward to the sealing plate 22, only the liquid phase is allowed to flow slowly downward from the liquid outlet of the reduced diameter port, while the rising gas phase is blocked below the sealing plate, i.e., in the first space 1A. It should be noted here that: Figure 2 The constricted opening in the middle is set in a conical shape. Correspondingly, the overflow outlet 221 on the sealing plate 22 is also set in a conical shape. During normal operation of the equipment, the rising gas phase can rise from the overflow outlet 221 on the sealing plate and enter the rising gas bypass 2. When the filter screen 112 of the catalyst 110 is blocked, the liquid level gradually rises and flows into the overflow pipe 21, causing the overflow pipe to extend downward (refer to...). Figure 3 , Figure 3 The design incorporates a flat, constricted inlet with a liquid outlet at the center, which effectively blocks the rising gas phase from below. Other similar methods can also be used, as long as the overflow pipe 21 extends downwards to block the overflow outlet on the sealing plate 22 and obstructs the rising gas phase.

[0045] Furthermore, after the rising gas phase is blocked, the gas pressure in the first space 1A rises rapidly, at which point the filter screen 112 of the catalyst can be blown open in reverse. Specifically, under the action of the overflow liquid phase, the corrugated hose section on the overflow pipe 21 is stretched, the rising gas phase channel becomes smaller until the overflow pipe blocks the gap in the sealing plate (i.e., the overflow outlet 221 on the sealing plate), and the liquid phase in the overflow pipe flows out slowly through the liquid outlet of the overflow pipe; the rising gas phase cannot pass through the rising gas bypass 2 normally and accumulates in the first space 1A between the catalyst layer 11 and the packing layer 12. The pressure here gradually increases until the gas blows open the filter screen 112 blocked by the catalyst layer 11, and the liquid phase resumes its descending channel. When the liquid phase in the overflow pipe 21 is completely drained, the overflow pipe returns to its original length, and the rising gas phase can re-enter the rising gas bypass 2.

[0046] In this embodiment, the retractable overflow pipe in the rising gas bypass can be extended downward without the need for additional power. This not only allows the overflowing liquid phase to be guided into the bypass and bypass the blockage, but also blocks the rising gas phase and creates a short-term high-pressure state in the first space. The increased gas pressure is used to blow open the blocked catalyst filter and clear the blockage.

[0047] Further as Figure 1 As shown, preferably but not limitingly, the reaction mass transfer channel 1 is provided with first disassembly flanges 4 at both ends for replacement after the catalyst and / or packing fails. Further combined with... Figure 2 , 3 As shown, the area from below the packing layer 12 to the first disassembly flange 4 within the reaction mass transfer channel 1 is the second space 1B. A riser branch pipe 3 is provided on the side wall of the second space 1B to provide the rising high-temperature gas phase. Further as... Figure 2 , 3 As shown, the rising gas branch pipe 3 may include a vertical section 31 and a bent section 32. The bent section 32 extends obliquely downward from the top of the vertical section 31 to the side wall of the reaction mass transfer channel 1 and communicates with the second space 1B. With this arrangement, without affecting the supply of rising gas phase, the bent section 32 can effectively prevent the descending liquid phase from flowing into the gas phase branch pipe. On the other hand, the presence of the second space 1B can provide a buffer for the gas phase exiting the bent section 32, causing it to change its running direction and move vertically upward. Further combining... Figure 1 A second disassembly flange 5 is provided at the corresponding position on the vertical section 31 of the riser branch pipe 3 and on the riser bypass 2, i.e., a second disassembly flange 5 is provided at both ends of the riser channel. In this way, when the catalyst and / or packing needs to be replaced, the entire catalytic reactive distillation unit 100A can be disassembled from the first disassembly flange 4 and the second disassembly flange 5 without affecting the normal operation of other catalytic reactive distillation units in the catalytic reactive distillation equipment 100.

[0048] Example 2

[0049] like Figure 1 As shown, this embodiment provides a catalytic reactive distillation apparatus 100, which includes the catalytic reactive distillation unit 100A of the aforementioned embodiment 1. Multiple catalytic reactive distillation units 100A are arranged laterally on each tray. Further, the upper end of the reaction mass transfer channel 1 in each catalytic reactive distillation unit 100A is connected to the liquid phase main pipe 6. The liquid phase main pipe 6 receives liquid phase products from the upper tray and enters the reaction mass transfer channel 1 in each catalytic reactive distillation unit on the same tray. Further, the gas riser bypass 2 in each catalytic reactive distillation unit is connected to the gas phase main pipe 7, and the gas riser branch pipe 3 is connected to the gas phase main pipe 7 of the lower tray.

[0050] Using the equipment of this embodiment, multiple catalytic reactive distillation units can operate simultaneously, which not only improves the overall reaction mass transfer efficiency, but also makes it possible to replace the catalyst and / or packing in one or more reaction mass transfer channels online.

[0051] Example 3

[0052] This embodiment provides a catalytic reactive distillation method, utilizing the catalytic reactive distillation unit from Embodiment 1 and the catalytic reactive distillation equipment from Embodiment 2. Multiple catalytic reactive distillation units can be arranged laterally on each tray. The method of this embodiment includes the following steps:

[0053] In step S101, two or more low-temperature liquid phase reactants enter the catalyst layer 11 in the reaction mass transfer channel 1 from top to bottom to carry out a catalytic reaction.

[0054] In step S102, the liquid phase product after the catalytic reaction merges with the high-temperature gas phase rising from the bottom in the packing layer 12 of the reaction mass transfer channel 1 and undergoes gas-liquid mass transfer. The rising gas phase after mass transfer carries the light components in the liquid phase product into the rising gas bypass 2 to complete the mass transfer separation (i.e., complete the distillation process).

[0055] The steps described above in this embodiment can not only increase the gas phase flow rate within this unit and effectively reduce the pressure drop within the reaction mass transfer channel 1, but also effectively save equipment space.

[0056] Furthermore, when the catalytic reaction has been underway for a period of time and the filter screen 112 of the catalyst layer 11 becomes clogged, the liquid phase enters the overflow pipe 21 provided in the rising gas bypass 2 through the overflow inlet 13; the overflow pipe 21 extends downward to the sealing plate 22, allowing the liquid phase to flow out through the overflow outlet and enter the first space 1A in the reaction mass transfer channel 1, while the rising gas phase is blocked in the first space 1A, and the gas pressure in the first space rises until the clogged filter screen is cleared.

[0057] Furthermore, when the catalytic reactive distillation unit 100 needs to replace the catalyst and / or packing after operating for a period of time, a certain catalytic reactive distillation unit 100A is completely disassembled from the first disassembly flange 4 and the second disassembly flange 5, while other catalytic reactive distillation units continue to operate normally, thus completing the online replacement of the catalyst and / or packing.

[0058] The following is a specific example to illustrate the process method of the present invention:

[0059] The catalytic reactive distillation unit and equipment of this invention utilize a β-zeolite catalyst and stainless steel θ-ring packing. The volume fraction of ethylene in the feed catalytic dry gas is 15%, the benzene-to-ethylene molar ratio is 6, the feed pressure is 1.8 MPa, the reaction temperature is 175 °C, and the catalytic dry gas mass hourly space velocity (MSV) is 0.25 h⁻¹. -1 .

[0060] The raw material enters from the packing layer at the bottom of the equipment, providing heat to the liquid at the bottom of the column to vaporize it. The vaporized vapor and the reflux liquid from the top of the equipment react counter-currently in the reaction mass transfer channel, undergoing reaction and distillation separation. The descending liquid phase reacts in the catalyst layer, specifically ethylene reacting with benzene to produce ethylbenzene. The reaction liquid product descends to the packing layer, where the rising high-temperature gas and the descending low-temperature liquid undergo mass transfer separation. The lighter components continue to rise as gas through the riser bypass, thus separating the lighter components from the liquid product.

[0061] Under these conditions, the ethylene conversion rate is >95%, and the ethylbenzene selectivity is >94%. After two months of operation, the ethylene conversion rate is >93%, and the ethylbenzene selectivity is >93%.

[0062] Under the same experimental conditions, using existing distillation equipment with the same height and dimensions as this invention, the ethylene conversion rate was >93% and the ethylbenzene selectivity was >90%. After two months of operation, the ethylene conversion rate was >85% and the ethylbenzene selectivity was >83%.

[0063] 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 catalytic reactive distillation unit, characterized in that, include: The reaction mass transfer channel receives low-temperature liquid reactants flowing from top to bottom at its upper end and high-temperature gaseous phase flowing from bottom to top at its lower end; the reaction mass transfer channel is provided with a catalyst layer and a packing layer, with the catalyst layer located above the packing layer and a first space between the two. A rising gas bypass is located outside the reaction mass transfer channel and communicates with the first space. The liquid phase product after the catalytic reaction merges with the high-temperature gas phase in the packing layer and undergoes gas-liquid mass transfer. The rising gas phase after mass transfer carries the light components in the liquid phase product into the rising gas bypass to complete mass transfer separation. A clearing mechanism is provided at a corresponding position in the catalyst layer within the rising gas bypass. When the descending liquid phase is obstructed in the catalyst layer, the gas phase pressure in the first space is used to clear the filter screen of the catalyst layer. The clearing mechanism includes: an overflow pipe, the upper end of which is connected to the overflow inlet located above the catalyst layer in the reaction mass transfer channel, and the lower end is a narrowing orifice. The overflow pipe is provided with a corrugated section to allow the overflow pipe to extend downward after the overflowing liquid phase enters and fills the overflow pipe; a sealing plate is provided below the narrowing orifice, and an overflow outlet is opened on the sealing plate, which is directly opposite the narrowing orifice. When the overflow pipe extends downward to the sealing plate, the rising gas phase is blocked in the first space.

2. The catalytic reactive distillation unit according to claim 1, characterized in that, The reaction mass transfer channel is provided with first disassembly flanges at both ends, which are used to disassemble the reaction mass transfer channel as a whole and replace it after the catalyst and / or packing fails.

3. The catalytic reactive distillation unit according to claim 2, characterized in that, The reaction mass transfer channel, from below the packing layer to the first disassembly flange position, forms a second space. The side wall of this second space is equipped with a gas riser pipe for supplying the high-temperature gas phase.

4. The catalytic reactive distillation unit according to claim 3, characterized in that, The rising gas branch pipe includes a vertical section and a bent section. The bent section extends obliquely downward from the top of the vertical section to the side wall of the reaction mass transfer channel and communicates with the second space.

5. The catalytic reactive distillation unit according to claim 4, characterized in that, A second disassembly flange is provided at the corresponding position of the first disassembly flange on the vertical section of the gas riser branch pipe and on the gas riser bypass.

6. A catalytic reactive distillation apparatus, characterized in that, It includes a catalytic reactive distillation unit as described in any one of claims 1 to 5, wherein multiple catalytic reactive distillation units are provided on each tray and arranged laterally.

7. The catalytic reactive distillation apparatus according to claim 6, characterized in that, The upper end of the reaction mass transfer channel in each of the catalytic reactive distillation units is connected to a liquid phase header, which receives liquid phase products from the upper tray.

8. The catalytic reactive distillation apparatus according to claim 6, characterized in that, Each of the aforementioned catalytic reactive distillation units has a riser bypass connected to the gas phase main, and each riser branch is connected to the gas phase main of the lower tray.

9. A catalytic reactive distillation method, characterized in that, The application of the catalytic reactive distillation unit as described in any one of claims 1 to 5, wherein multiple catalytic reactive distillation units are arranged laterally on each tray, includes the following steps: A. Two or more cryogenic liquid-phase reactants enter the catalyst layer in the reaction mass transfer channel from top to bottom to carry out a catalytic reaction; B. After the catalytic reaction, the liquid phase product merges with the high-temperature gas phase rising from the bottom in the packing layer of the reaction mass transfer channel and undergoes gas-liquid mass transfer. The rising gas phase after mass transfer carries the light components in the liquid phase product into the rising gas bypass, completing the mass transfer separation.

10. The catalytic reactive distillation method according to claim 9, characterized in that, When the catalytic reaction has been going on for a period of time and the filter screen of the catalyst layer becomes clogged, the liquid phase enters the overflow pipe set in the rising gas bypass through the overflow inlet; the overflow pipe extends downward to the sealing plate so that the liquid phase flows out through the overflow outlet and enters the first space in the reaction mass transfer channel, while the rising gas phase is blocked in the first space, and the gas pressure in the first space rises until the clogged filter screen is cleared.

11. The catalytic reactive distillation method according to claim 9, characterized in that, When the catalytic reactive distillation equipment needs to be replaced after operating for a period of time, one of the catalytic reactive distillation units is completely disassembled from the first disassembly flange and the second disassembly flange, while the other catalytic reactive distillation units continue to operate normally, thus completing the online replacement of the catalyst and / or packing.

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