Catalytic reaction unit and reactive distillation tower

Abstract

The present invention discloses a catalytic reaction unit and a reactive distillation tower. The catalytic reaction unit includes: a catalyst bed for filling a solid catalyst, the catalyst bed being circumferentially provided with a liquid-phase circulation channel; a liquid-phase feed subunit disposed at a corresponding position in the liquid-phase circulation channel of the first catalyst bed, wherein the liquid-phase feed radially enters from the bottom of the catalyst bed and circulates within the bed through the liquid-phase circulation channel; a gas-phase feed subunit, wherein the first gas-phase distribution pipe is disposed below the catalyst bed, wherein the gas-phase feed enters the catalyst bed from bottom to top; and a gas-phase channel, which is relatively isolated from the gas-phase feed subunit, wherein the gas-phase product generated after the gas-phase feed and the liquid-phase feed react in the catalyst bed directly enters the gas-phase channel. The present invention can not only solve the problem of separation efficiency of gas-phase reaction products, but also effectively ensure sufficient reaction in each catalyst bed.

Description

Technical Field

[0001] The present invention relates to the field of petrochemical industry, in particular to a catalytic reaction unit and a reaction distillation tower using the unit. Background Art

[0002] Catalytic distillation originated in the chemical industry, a technology that combines catalytic reaction and distillation operations within a single vessel. It offers numerous advantages, including energy conservation, high efficiency, and economical efficiency. Given its advantages, catalytic distillation technology has now achieved relatively mature application in the chemical industry. As early as the 1960s, American companies began using catalytic distillation to address the difficulty of separating mixtures of normal olefins, isoolefins, and alkanes using traditional distillation due to their similar boiling points. Subsequently, a variety of catalytic distillation equipment emerged, tailored to the characteristics of different reactions. For example, a left-right structure combines both distillation and reaction functions. The left side houses the distillation function and is equipped with distillation trays, while the right side houses the reaction function and is filled with the catalyst required for the reaction. The two chambers are separated by a partition. Another example is the more common top-down structure of catalytic distillation equipment, where the top-down structure refers to the relative positions of the reaction zone and the distillation zone. US Pat. No. 6,723,886 B2 discloses a top-down structured catalytic distillation equipment for producing methanol from synthesis gas. There are multiple layers of fixed beds in the equipment. The diameter of the reaction zone can vary at different heights. Whether to fill the reaction zone with catalyst and the thickness of the filled catalyst can be determined according to the situation. External heat exchangers, dehydration devices or paraffin separation devices and reflux side lines can be installed at side lines at different positions. The entire catalytic distillation unit can also be surrounded by a separate cooling device.

[0003] Given the presence of gaseous components in the product, the industry has proposed the concept of gas channels to facilitate gas flow through the catalyst bed. For example, a gas channel can be embedded in the middle of a catalytic distillation apparatus. This gas channel allows the gas phase in the lower bed to flow directly to the upper distillation trays for mass transfer without passing through the catalyst bed. Multiple gas channels can also be provided in a catalytic distillation apparatus. The catalytic distillation tower is a cylindrical outer tube sealed at the top and bottom, with multiple cylindrical gas channels perpendicular to the cross section. The gas channels are embedded in the reaction zone, and the channel terminals connect to the open areas or media within the rectifying and stripping sections. The outer tube of the reaction zone is filled with a high-density catalyst, and the inner tube wall can be perforated to allow close contact with the catalyst.

[0004] In summary, the existing catalytic distillation technology itself improves the reaction efficiency and product separation. In the application of catalytic distillation technology, reactors and their internal components have also formed various forms, but the efficiency of current reactors and internal components needs to be further improved. In particular, the existing technology cannot effectively solve the problem of timely separation of gas-phase reaction products from the reaction zone. In addition, the residence time of liquid-phase materials in each catalyst bed layer is relatively short, which will greatly reduce the gas-liquid reaction efficiency. Therefore, there is an urgent need for a catalytic reaction unit and a distillation tower using the reaction unit to solve the separation efficiency problem in the existing technology. In the case where the gas-phase products can undergo secondary reactions, efficient separation can still be carried out; at the same time, the reaction efficiency problem of each catalyst bed layer can be effectively solved.

[0005] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the Invention

[0006] The object of the present invention is to provide a catalytic reaction unit and a reaction distillation tower using the unit, which can not only solve the separation efficiency problem of gas phase reaction products, but also effectively ensure sufficient reaction in each catalyst bed layer.

[0007] To achieve the above-mentioned purpose, according to the first aspect of the present invention, there is provided a catalytic reaction unit, comprising: a catalyst bed, which is used to fill a solid catalyst, and a liquid-phase circulation channel is provided around the catalyst bed; a liquid-phase feed subunit, which is arranged at a corresponding position of the liquid-phase circulation channel of the first catalyst bed, and the liquid-phase feed radially enters the catalyst bed from the bottom and circulates within the bed through the liquid-phase circulation channel; a gas-phase feed subunit, whose first gas-phase distribution pipe is arranged below the catalyst bed, and the gas-phase feed enters the catalyst bed from bottom to top; a gas-phase channel, which is in a relatively isolated state from the gas-phase feed subunit, and the gas-phase product generated after the gas-phase feed and the liquid-phase feed react in the catalyst bed directly enters the gas-phase channel.

[0008] Furthermore, in the above technical solution, the gas phase channel may be located in the middle of the catalytic reaction unit and pass through all catalyst beds from bottom to top.

[0009] Furthermore, in the above technical solution, an overflow channel is provided outside the liquid phase circulation channel, and a portion of the unreacted liquid phase feed can enter the next layer of liquid phase circulation channel from the overflow channel through the guide pipe.

[0010] Furthermore, in the above technical solution, the gas phase feed subunit may be further provided with a second gas phase distribution pipe, which is arranged at the bottom of the liquid phase circulation channel and at the inlet where the liquid phase feed radially enters the catalyst bed.

[0011] Furthermore, in the above technical solution, a distribution umbrella may be provided above the catalyst bed. The umbrella surface of the distribution umbrella is a hollow structure, and the gas phase products after the reaction directly enter the gas phase channel through the hollow holes.

[0012] Furthermore, in the above technical solution, the outer edge of the distribution umbrella may extend toward the liquid phase circulation channel.

[0013] Furthermore, in the above technical solution, a hollow umbrella-shaped cap may be provided at the entrance of each layer of the gas phase channel, and the outer edge of the cap extends toward the liquid phase circulation channel of this layer.

[0014] Furthermore, in the above technical solution, a gas sealing baffle may be provided at a corresponding position of the first gas phase distribution pipe, and the gas sealing baffle is used to isolate the gas phase feed from the gas phase product and block the liquid phase feed from the overflow channel.

[0015] Furthermore, in the above technical solution, the liquid-phase feed subunit may further include: a liquid-phase feed pipe, which extends along the radial direction of the catalytic reaction unit; a liquid-phase distribution pipe, which is a double-layer concentric ring and intersects orthogonally or tangentially with the liquid-phase feed pipe, and the tube wall of the liquid-phase distribution pipe is provided with a plurality of channels for evenly distributing the liquid-phase feed to all directions of the liquid-phase circulation channel.

[0016] Furthermore, in the above technical solution, the gas-phase feeding subunit may further include: a gas-phase feeding pipe, which extends along the radial direction of the catalytic reaction unit; a gas-phase distribution pipe, which includes a first gas-phase distribution pipe and a second gas-phase distribution pipe, which gas-phase distribution pipe intersects the gas-phase feeding pipe orthogonally or tangentially, and a plurality of channels are provided on the wall surface of the gas-phase distribution pipe.

[0017] Furthermore, in the above technical solution, the first gas phase distribution pipe may be annular or multi-layer concentric annular, and the openings of the channels on the wall of the first gas phase distribution pipe face upward.

[0018] Furthermore, in the above technical solution, the second gas phase distribution pipe may be a double-layer concentric ring, wherein the openings of the channels on the outer ring wall face inward, and the openings of the channels on the inner ring wall face outward.

[0019] Furthermore, in the above technical solution, the gas-phase feeding subunit may further include: a gas-phase distribution plate, which is located at the bottom of the catalyst bed and is disk-shaped as a whole, and has a plurality of holes evenly distributed on the gas-phase distribution plate.

[0020] Furthermore, in the above technical solution, the catalyst bed height can be set to 10 mm to 1000 mm according to different reaction systems.

[0021] Furthermore, in the above technical solution, the upper edge of the overflow channel may be 10 to 100 mm higher than the upper surface of the catalyst bed.

[0022] According to a second aspect of the present invention, a reactive distillation tower is provided. The reactive distillation tower may be a single-layer or multi-layer tray structure using any one of the aforementioned catalytic reaction units.

[0023] Furthermore, in the above technical solution, the reactive distillation tower can be applied to a reaction system in which at least one liquid feed and at least one gaseous feed undergo a chemical reaction on a solid catalyst, and the reaction products include at least one gaseous product.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1) The gaseous products generated by the chemical reaction of the gaseous and liquid feeds used in the present invention in the catalyst bed will leave the reaction zone in a timely manner and will not re-enter the upper catalyst bed, thereby avoiding secondary reactions of the target products and improving the selectivity of the reaction. The timely departure of the gaseous products from the reaction zone increases the driving force of the reaction and improves the equilibrium conversion rate.

[0026] 2) The liquid phase feed used in the present invention can quickly pass through the catalyst bed under the impetus of the gas phase feed, and at the same time, the liquid phase feed can be circulated into the catalyst bed of this layer, thereby increasing the cumulative residence time of the reactants in the catalyst bed;

[0027] 3) The present invention does not need to avoid the occurrence of flooding. While meeting the process requirements, the requirements for gas velocity and porosity are more relaxed.

[0028] 4) The distribution umbrella can effectively intercept the liquid entrained in the gas phase product from entering the gas phase channel, while guiding the liquid phase back to the liquid phase circulation channel;

[0029] 5) The draft tube can effectively prevent the liquid phase from being carried into the gas phase channel by the gas phase product;

[0030] 6) The provision of the second gas phase distribution pipe can enhance the circulation effect of the liquid phase in this layer, ensuring that the liquid phase in the liquid phase circulation channel smoothly enters the catalyst bed;

[0031] 7) The catalytic reaction unit of the present invention is applicable to a reaction system in which at least one liquid feed and at least one gaseous feed undergo a chemical reaction on a solid catalyst, and the reaction products include at least one gaseous product.

[0032] The above description is only an overview of the technical solution of the present invention. In order to more clearly 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 purposes, 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1It is a structural schematic diagram of the catalytic reaction unit and the reactive distillation tower of the present invention.

[0034] Figure 2 It is a bottom view of the liquid phase distribution pipe in the catalytic reaction unit of the present invention.

[0035] Figure 3 It is a schematic diagram of the flow direction of liquid feed entering the catalyst bed in the catalytic reaction unit of the present invention.

[0036] Figure 4 It is a top view of the first gas phase distribution pipe in the catalytic reaction unit of the present invention (an embodiment using a single ring).

[0037] Description of main reference numerals:

[0038] 1-reactive distillation column; 2-gas phase channel; 3-umbrella cap; 4-catalyst bed; 5-liquid phase distribution pipe; 511-outer tube of liquid phase distribution pipe; 512-outer liquid phase channel; 521-inner tube of liquid phase distribution pipe; 522-inner liquid phase channel; 6-first gas phase distribution pipe; 611-tube body; 612-gas phase channel; 7-draft guide pipe; 8-outer overflow weir; 9-outer tube of second gas phase distribution pipe Tube; 10-gas sealing baffle; 11-outer guide weir; 12-gas phase distribution plate; 13-support plate; 14-catalyst baffle; 15-inner tube of the second gas phase distribution pipe; 16-inner overflow weir; 17-inner guide weir; 18-distribution umbrella; 21-liquid phase feed; 22-outer liquid phase guide channel; 23-inner liquid phase guide channel; 31-gas phase feed; 32-gas phase discharge; 33-liquid phase discharge. DETAILED DESCRIPTION

[0039] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0040] Unless expressly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising” will be understood to include the stated elements or components but not to exclude other elements or components.

[0041] In this document, for ease of description, spatially relative terms such as "below," "beneath," "down," "above," "above," etc. may be used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that the spatially relative terms are intended to encompass different orientations of an object in use or operation in addition to the orientation depicted in the drawings. For example, if the object in the figure is turned over, the element described as being "below" or "below" other elements or features will be oriented "above" the element or feature. Therefore, the exemplary term "below" can include both below and above directions. Objects may also have other orientations (rotated 90 degrees or other orientations) and the spatially relative terms used herein should be interpreted accordingly.

[0042] In this document, the terms "first", "second", etc. are used to distinguish two different elements or parts, and are not used to limit specific positions or relative relationships. In other words, in some embodiments, the terms "first", "second", etc. can also be interchangeable with each other.

[0043] like Figure 1 As shown, the catalytic reaction unit of the present invention is an internal component of a reactive distillation column 1 and includes a catalyst bed 4, a liquid-phase feed subunit, a gas-phase feed subunit, and a gas-phase channel 2. The catalyst bed 4 is filled with solid catalyst. A support plate 12 is provided below the catalyst bed 4, primarily supporting the catalyst bed and ensuring its axial stability in the reactive distillation column 1. Liquid-phase circulation channels are provided circumferentially within and around the catalyst bed. The liquid-phase feed subunit is positioned at a corresponding position within the liquid-phase circulation channel of the first catalyst bed (i.e., the topmost layer of a single or multi-layer catalyst bed), ensuring that the liquid phase flows downward to the bottom of the catalyst bed 4. Liquid-phase feed 21 enters the catalyst bed radially from the bottom and circulates within the bed through the liquid-phase circulation channel. The gas-phase feed subunit includes a first gas-phase distribution pipe 6, which is positioned below the catalyst bed. The gas-phase feed 31 enters the catalyst bed from the bottom up. The independent gas-phase channel 2 is relatively isolated from the gas-phase feed subunit. The gas-phase product generated after the gas-phase feed and liquid-phase feed react in the catalyst bed 4 can directly enter this gas-phase channel 2. Preferably, but not limitingly, the gas-phase channel 2 is located in the middle of the reactive distillation column and extends through all catalyst beds from bottom to top. Furthermore, a hollow umbrella-shaped cap 3 can be provided at the entrance of each layer of the gas-phase channel 2. The outer edge of the cap 3 extends toward the liquid-phase circulation channel of that layer, effectively intercepting droplets in the gas-phase product.

[0044] Further Figure 1 As shown, the liquid phase circulation channel can be constructed in the following way: Figure 1An inner weir 17 and an outer weir 11 (i.e., the outer facade of the catalyst bed) are provided on both sides of the catalyst bed 4. The inner and outer weirs guide the liquid phase. When the liquid phase fills the catalyst bed, it is diverted to the outside of the weirs. The upper edge of the inner and outer weirs can be flush with the upper edge of the catalyst bed, preferably 1 to 10 mm above the upper surface of the catalyst bed. An inner overflow weir 16 and an outer overflow weir 8 are provided at a certain distance outside the inner weir 17 and the outer weir 11, respectively. The space between the weirs and the overflow weirs constitutes the liquid phase circulation channel of the present invention. The bottom of the inner and outer weirs is higher than the bottom of the catalyst bed 4, thus forming a radial inlet for the liquid phase at the bottom of the catalyst bed. This radial inlet has a certain thickness, thereby forming an outer liquid phase diversion channel 22 and an inner liquid phase diversion channel 23, respectively. The liquid phase feed enters the catalyst bed 4 radially through the diversion channel. The horizontal inclination angle of the radial diversion channel can be set to 0 to 45 degrees.

[0045] An overflow channel is provided outside the liquid-phase circulation channel. This overflow channel is coaxially arranged and arranged in an annular pattern, extending both inside and outside the catalyst bed. The space between the outer overflow weir 8 and the tower wall constitutes the outer overflow channel, while the space between the inner overflow weir 16 and the outer wall of the gas-phase channel constitutes the inner overflow channel. Liquid product and a portion of unreacted liquid feed overflow from this overflow channel and fall onto a liquid receiving pan 13. From there, they flow through a draft tube 7 into the liquid-phase circulation channel of the next layer, serving as the liquid feed for the next catalyst bed. The draft tube 7 can be mounted on the liquid receiving pan 13.

[0046] Further Figure 1 As shown, a distribution umbrella 18 is positioned above the catalyst bed 4. Its surface is a hollow structure, uniformly distributed with multiple holes. The reacted gaseous products pass through the holes and directly enter the gas phase channel 2. The outer edge of the distribution umbrella 18 extends toward the liquid phase circulation channel. Liquid products entrained by the gaseous products are intercepted by the distribution umbrella 18 and returned to the liquid phase circulation channel.

[0047] like Figure 1 As shown, the liquid phase feed subunit further includes a liquid phase feed pipe (not shown in the figure) and a liquid phase distribution pipe 5. The liquid phase feed pipe extends in the radial direction of the catalytic reaction unit (i.e., the direction of the liquid phase feed 21 in the figure). Figure 2 As shown, liquid-phase distribution pipe 5 is a double-layered concentric ring that intersects the liquid-phase feed pipe orthogonally or tangentially. Its wall is provided with multiple channels, namely, outer liquid-phase channels 512 on outer tube 511 and inner liquid-phase channels 522 on inner tube 521. These channels evenly distribute the liquid-phase feed in all directions within the liquid-phase circulation channel. Within the liquid-phase circulation channel, the liquid-phase feed is guided to the catalyst bed 4 via the aforementioned radial guide channels at the bottom of the catalyst bed 4.

[0048] Further Figure 1 As shown, the gas-phase feeding subunit includes a gas-phase feeding pipe (not shown in the figure), a gas-phase distribution pipe and a gas-phase distribution plate 12. Among them, the gas-phase feeding pipe extends along the radial direction of the catalytic reaction unit (i.e., the direction of the gas-phase feed 31). The gas-phase distribution pipe is orthogonal or tangentially intersected with the gas-phase feeding pipe, and a plurality of channels are provided on the wall of the gas-phase distribution pipe. Specifically, the gas-phase distribution pipe is provided in each layer of the catalyst bed, including the aforementioned first gas-phase distribution pipe 6. Preferably, but not restrictively, the tube body 611 of the first gas-phase distribution pipe 6 is annular. In order to make the gas-phase feed entering the catalyst bed 4 more uniform, the first gas-phase distribution pipe 6 can also be designed as a multi-layer concentric ring. The gas-phase channel 612 on the wall of the first gas-phase distribution pipe 6 opens upward (reference Figure 4 ). Further, a gas sealing baffle (preferably an annular structure, refer to Figure 1 ), the gas sealing baffle is used to isolate the gas phase feed from the first gas phase distribution pipe 6 from the gas phase product, and at the same time block the liquid phase feed from the overflow channel so that it directly enters the guide pipe 7. Further, preferably but not restrictively, the gas phase distribution pipe may also include a second gas phase distribution pipe, which is a double-layer concentric ring, namely the outer layer pipe 9 and the inner layer pipe 15. The openings of the channels on the wall of the outer layer pipe 9 face inward, and the openings of the channels on the wall of the inner layer pipe face outward. Combined Figure 3 As shown in FIG. 1 , which is a schematic diagram of the flow direction of the liquid phase feed into the catalyst bed, due to the second gas phase distribution pipe being arranged at the liquid phase inlet at the bottom of the catalyst bed and the design of the opening direction of the outer layer pipe 9 and the inner layer pipe 15, the gas phase feed in the second gas phase distribution pipe can effectively enhance the circulation effect of the liquid phase in the catalyst bed layer, ensuring that the liquid phase enters the catalyst bed smoothly. Figure 1 As shown, the gas phase distribution plate 12 is located at the bottom of the catalyst bed 4 and is disk-shaped as a whole. The gas phase distribution plate 12 is evenly and densely distributed with multiple holes, which can allow the gas phase feed from the first gas phase distribution plate 6 to evenly enter the catalyst bed 4.

[0049] Further Figure 1 As shown, the height of each catalyst bed in the reactive distillation tower 1 can be the same or different, depending on the different chemical reaction systems. The catalyst bed is fixed with a screen above and on the sides to keep the bed relatively stable. The bed height is set to 10 mm to 1000 mm.

[0050] The reaction process is described below, combining the specific structure of the aforementioned catalytic reaction unit. Liquid feed 21 flows downward through liquid distribution pipe 5 to the bottom of the catalyst bed. Propelled by the gaseous feed in the second gas distribution pipe, it enters the catalyst bed 4 radially. Simultaneously, gaseous feed from the first gas distribution pipe 6 at the bottom of the catalyst bed 4 enters the catalyst bed from bottom to top, achieving a gas-liquid-solid three-phase reaction within the catalyst bed. The resulting gaseous product passes through distribution umbrella 18 and directly enters gas channel 2 located in the center of reactive distillation column 1. When the unreacted liquid in catalyst bed 4 fills the bed, it is directed into the liquid circulation channel and then returned to the catalyst bed in the current layer. Once the liquid circulation channel is filled with liquid and overflows into the overflow channel, the liquid enters the liquid circulation channel of the next layer through draft tube 7. Draft tube 7 can be evenly distributed along the circumference, with the size and number of openings determined by the liquid feed load. The reaction process for the lower catalyst bed follows a similar pattern.

[0051] In the catalytic reaction unit of the present invention, liquid-phase feed and gas-phase feed undergo catalytic reactions within the catalyst bed. Gas-phase products and unreacted gas-phase feed rise through the gas-phase channel and leave the reaction system. Gas-phase products generated after the reactants undergo chemical reactions within the catalyst bed will promptly leave the reaction zone and will not re-enter the catalyst bed above, thereby avoiding secondary reactions of the target product and improving the selectivity of the reaction. At the same time, due to the departure of the products within the reaction zone, the driving force of the reaction is increased and the equilibrium conversion rate is improved. In addition, in the present invention, the liquid-phase feed can quickly pass upward through the catalyst bed under the impetus of the gas-phase feed, while the liquid-phase feed is circulated into the catalyst bed of this layer, thereby increasing the cumulative residence time of the reactants in the catalyst bed and allowing the chemical reaction to proceed fully. Unlike traditional reactive distillation towers, the present invention does not need to avoid the occurrence of liquid flooding. While meeting the process requirements, the requirements for gas velocity and porosity are more relaxed.

[0052] The present invention also provides a reactive distillation tower. Utilizing the above-described catalytic reaction unit, the reactive distillation tower 1 can have a multi-layer tray structure. The number of catalyst beds within the reactive distillation tower can be one or more. The reactive distillation tower 1 of the present invention is suitable for use in reaction systems in which at least one liquid feed and at least one vapor feed undergo a chemical reaction over a solid catalyst, with at least one vapor product being the reaction product. Examples include hydrocracking of petroleum fractions and chemical synthetic oils, hydrodewaxing of diesel and lubricating oil fractions, and hydrotreating of various petroleum fractions.

[0053] The gas phase channel of the reactive distillation tower 1 of the present invention is a common channel for removing gaseous products generated by chemical reactions on each tray. In embodiments of the present invention, the liquid feed is located entirely at the top of one tray. Alternatively, liquid feed may be located on some or all trays, while gaseous feed is located at the bottom of each tray. Above each tray is a catalyst loading area. Liquid feed enters the catalyst bed radially and flows upward through it. Gas feed enters from below the tray and reacts under the action of the catalyst. The gaseous material generated after the reaction directly exits the reaction system and enters the central gas phase channel. The liquid phase leaves the current bed and enters the next bed through a draft tube. Because reaction and separation occur simultaneously, the reaction equilibrium can be disrupted, effectively improving the conversion rate of the reactants and the selectivity of the desired product.

[0054] Example 1

[0055] The catalytic reaction unit of the present invention is used in the hydrocracking reactor of a catalytic diesel hydrocracking process. A pre-refining reactor is connected in series upstream of the cracking reactor to remove impurities from the feedstock. The catalyst used is the same catalyst used in industrial plants. The cracking product has a gasoline fraction yield of 50.1%, a gasoline octane number (RON) of 88.2, and a liquid yield of 91.1%.

[0056] Operating conditions and results:

[0057] The density of catalytic diesel is 0.9464 g·cm -3 , distillation range 168-370℃;

[0058] Hydrogen purity 99.9%;

[0059] Refined oil nitrogen content 70-100mg.kg -3 ;

[0060] The operating pressure of the catalytic distillation tower is 4.0 MPa;

[0061] Number of catalyst beds in catalytic distillation tower: 1 layer;

[0062] Cracking liquid hourly space velocity LHSV: 1.5h -1 ;

[0063] Hydrogen to oil volume ratio: 700:1;

[0064] Average reaction temperature: 350-360℃;

[0065] The gasoline fraction yield is 50.1%; the gasoline octane number RON is 88.2; and the liquid yield is 91.1%.

[0066] Example 2

[0067] The catalytic reaction unit of the present invention is used in the hydrocracking reactor of a catalytic diesel hydrocracking process. A pre-refining reactor is connected in series upstream of the cracking reactor to remove impurities from the crude oil. The catalyst is similar to that used in industrial plants and is fixed to the bed with stainless steel mesh. The cracked product gasoline fraction yield is 54.1%, the gasoline octane number (RON) is 93.3, and the liquid yield is 98.2%.

[0068] Operating conditions and results:

[0069] The density of catalytic diesel is 0.9464 g·cm -3 , distillation range 168-370℃;

[0070] Hydrogen purity 99.9%;

[0071] Refined oil nitrogen content 70-100mg.kg -3 ;

[0072] The operating pressure of the catalytic distillation tower is 4.0 MPa;

[0073] Number of catalyst beds in catalytic distillation tower: 5;

[0074] Cracking liquid hourly space velocity LHSV: 1.5h -1 ;

[0075] The load of the first-layer downcomer is designed to have an operational flexibility of 60%-130% based on the feed rate;

[0076] The gas phase feed load of each layer is the same (the gas phase flow rate can also be controlled according to the liquid phase load of each layer);

[0077] The diameter of the gas phase channel is the same at the top and bottom (it can also be set to be larger at the top and smaller at the bottom);

[0078] Hydrogen to oil volume ratio: 700:1;

[0079] Average reaction temperature: 350-360℃;

[0080] The gasoline fraction yield was 54.1%, the gasoline octane number RON was 93.3, and the liquid yield was 98.2%. Compared with the single-layer bed in Example 1, the effect of the invention was more obvious when the number of catalyst beds was 5.

[0081] Example 3

[0082] The catalytic reaction unit of the present invention is used in the hydrocracking reactor of a catalytic diesel hydrocracking process. A pre-refining reactor is connected in series upstream of the cracking reactor to remove impurities from the crude oil. The catalyst is the same type used in industrial plants and is fixed to the bed with stainless steel mesh. The gasoline fraction yield is 55.3%, the gasoline octane number (RON) is 93.1, and the liquid yield is 98.6%.

[0083] Operating conditions and results:

[0084] The density of catalytic diesel is 0.9464 g·cm -3 , distillation range 168-370℃;

[0085] Refined oil nitrogen content 70-100mg.kg -3 ;

[0086] The operating pressure of the catalytic distillation tower is 6.0 MPa;

[0087] Number of catalyst beds in catalytic distillation tower: 10;

[0088] Liquid hourly space velocity LHSV: 1.5h -1 ;

[0089] The load of the first-layer downcomer is designed to have an operational flexibility of 60%-130% based on the feed rate;

[0090] The gas phase feed load of each layer is the same (the gas phase flow rate can also be controlled according to the liquid phase load of each layer);

[0091] The diameter of the gas phase channel is the same at the top and bottom (it can also be set to be larger at the top and smaller at the bottom);

[0092] Hydrogen to oil volume ratio: 800:1;

[0093] Average reaction temperature: 360-380℃;

[0094] The gasoline fraction yield is 55.3%; the gasoline octane number RON is 93.1; and the liquid yield is 98.6%.

[0095] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise form disclosed, and it is apparent that many changes and variations are possible in light of the foregoing teachings. The exemplary embodiments are selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and variations. Any simple modifications, equivalent variations, and modifications made to the exemplary embodiments described above are intended to fall within the scope of protection of the present invention.

Claims

1. A catalytic reaction unit, characterized in that: include: A catalyst bed is used to fill a solid catalyst, and a liquid phase circulation channel is provided around the catalyst bed; an inner guide weir and an outer guide weir are provided on both sides of the catalyst bed, and an inner overflow weir and an outer overflow weir are provided at a certain distance outside the inner guide weir and the outer guide weir, respectively, and the space between the inner and outer guide weirs and the inner and outer overflow weirs constitutes the liquid phase circulation channel; A liquid-phase feed subunit is provided at a corresponding position of the liquid-phase circulation channel of the first catalyst bed layer, and the liquid-phase feed radially enters from the bottom of the catalyst bed layer and circulates within the bed layer through the liquid-phase circulation channel; A gas-phase feed subunit, comprising a first gas-phase distribution pipe and a second gas-phase distribution pipe, wherein the first gas-phase distribution pipe is arranged below the catalyst bed, and the gas-phase feed enters the catalyst bed from bottom to top; The second gas phase distribution pipe is arranged at the bottom of the liquid phase circulation channel, at the inlet where the liquid phase feed radially enters the catalyst bed; The gas phase channel is relatively isolated from the gas phase feed subunit, and the gas phase product generated after the gas phase feed and the liquid phase feed react in the catalyst bed directly enters the gas phase channel; the gas phase channel is located in the middle of the catalytic reaction unit and passes through all the catalyst beds from bottom to top.

2. The catalytic reaction unit according to claim 1, characterized in that: An overflow channel is provided outside the liquid phase circulation channel, and a portion of the unreacted liquid phase feed flows from the overflow channel through the guide pipe into the liquid phase circulation channel of the next layer.

3. The catalytic reaction unit according to claim 1, characterized in that: A distribution umbrella is provided above the catalyst bed. The umbrella surface of the distribution umbrella is a hollow structure, and the gas phase product after the reaction directly enters the gas phase channel through the hollow holes.

4. The catalytic reaction unit according to claim 3, characterized in that: The outer edge of the distribution umbrella extends toward the liquid phase circulation channel.

5. The catalytic reaction unit according to claim 1, characterized in that: A hollow umbrella-shaped cap is provided at the entrance of each layer of the gas phase channel, and the outer edge of the cap extends toward the liquid phase circulation channel of this layer.

6. The catalytic reaction unit according to claim 2, characterized in that: A gas sealing baffle is provided at a corresponding position of the first gas phase distribution pipe, and the gas sealing baffle is used to isolate the gas phase feed from the gas phase product and block the liquid phase feed from the overflow channel.

7. The catalytic reaction unit according to claim 1, characterized in that: The liquid phase feeding subunit further comprises: a liquid-phase feed pipe extending in a radial direction of the catalytic reaction unit; The liquid phase distribution pipe is a double-layer concentric ring and intersects the liquid phase feed pipe orthogonally or tangentially. The wall of the liquid phase distribution pipe is provided with multiple channels for evenly distributing the liquid phase feed to all directions of the liquid phase circulation channel.

8. The catalytic reaction unit according to claim 1, characterized in that: The gas phase feeding subunit further comprises: A gas-phase feed pipe extends along the radial direction of the catalytic reaction unit.

9. The catalytic reaction unit according to claim 1, characterized in that: The first gas phase distribution pipe is annular, and the openings of the channels on the wall of the first gas phase distribution pipe face upward.

10. The catalytic reaction unit according to claim 1, characterized in that: The second gas phase distribution pipe is a double-layer concentric ring, wherein the openings of the channels on the outer ring wall face inward, and the openings of the channels on the inner ring wall face outward.

11. The catalytic reaction unit according to claim 8, characterized in that: The gas phase feeding subunit further comprises: The gas phase distribution plate is located at the bottom of the catalyst bed and is in the shape of a plate as a whole. The gas phase distribution plate is evenly and densely distributed with a plurality of holes.

12. The catalytic reaction unit according to claim 1, characterized in that: The catalyst bed height is set to 10 mm to 1000 mm according to different reaction systems.

13. The catalytic reaction unit according to claim 2, characterized in that: The upper edge of the overflow channel is 10 to 100 mm higher than the upper surface of the catalyst in the bed.

14. A reactive distillation tower, characterized in that: The catalytic reaction unit according to any one of claims 1 to 13 is comprised, wherein the reactive distillation column is a single-layer or multi-layer tray structure.

15. The reactive distillation column according to claim 14, characterized in that The reactive distillation tower is suitable for a reaction system in which at least one liquid-phase feed and at least one gas-phase feed undergo a chemical reaction on a solid catalyst, and the reaction products include at least one gas-phase product.

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