Tubular fixed bed reactor

Abstract

The utility model relates to the field of chemical equipment, in particular to a tubular fixed bed reactor which comprises an upper end cover, a lower end cover, a shell pass cylinder, an upper tube plate, a lower tube plate and a plurality of reaction tubes, a tube pass inlet is formed in the upper end cover, a tube pass outlet is formed in the lower end cover, and a shell pass inlet and a shell pass outlet are formed in the shell pass cylinder; the gas distribution assembly is arranged inside the upper end cover; the lower distribution cylinder is positioned in the shell pass cylinder and surrounds the periphery of at least part of the reaction tubes; and a plurality of overflowing through holes are uniformly distributed in the side peripheral wall of the lower distribution cylinder. The gas distribution assembly is arranged, so that the catalyst in each reaction tube can be utilized more uniformly; by arranging the lower distribution cylinder, the shell pass medium at the shell pass inlet can be uniformly distributed, and the situation that part of reaction heat in the reaction tube cannot be taken away in time is avoided. The gas distribution assembly and the lower distribution cylinder are arranged in a combined manner, so that the tubular fixed bed reactor is good in reaction stability and high in product yield.

Description

Technical Field

[0001] This application relates to the field of chemical equipment, and more particularly, to a shell-and-tube fixed-bed reactor. Background Art

[0002] In the production processes in the chemical industry, synthesis reactions are often involved, such as the reactions of coal or natural gas to syngas and syngas to liquid fuels (hydrocarbons, alcohols, aldehydes, acetic acid series products, etc.) in the coal chemical industry. The above reactions are all exothermic reactions. Since the heat release of such reactions is large, local overheating of the catalyst bed layer often occurs, resulting in reduced selectivity and catalyst coking. In order to obtain high selectivity and effectively remove the reaction heat, a shell-and-tube fixed-bed reactor can be used. The catalyst is filled in the reaction tubes, and the heat transfer medium is outside the tubes.

[0003] In the current shell-and-tube fixed-bed reactors, there is a problem that the catalyst utilization rate in some reaction tubes is low, while the catalyst load in some other reaction tubes is too high, causing premature deactivation. At the same time, the heat removal effect of the reaction tubes is uneven, that is, the reaction heat in some reaction tubes cannot be taken away in time, resulting in coking, poor reaction stability, and low product yield. Summary of the Utility Model

[0004] The purpose of this application is to provide a shell-and-tube fixed-bed reactor, aiming to solve the technical problems in the existing shell-and-tube fixed-bed reactors, such as uneven utilization of the catalyst in each reaction tube and uneven heat removal in each reaction tube, which in turn lead to poor reaction stability and low product yield.

[0005] To achieve this purpose, the technical solution adopted in this application is: providing a shell-and-tube fixed-bed reactor, including an upper end cover, a lower end cover, a shell-side cylinder body disposed between the upper end cover and the lower end cover, an upper tube sheet disposed at the top inside the shell-side cylinder body, a lower tube sheet disposed at the bottom inside the shell-side cylinder body, and a plurality of reaction tubes disposed between the upper tube sheet and the lower tube sheet. A tube-side inlet is provided on the upper end cover, a tube-side outlet is provided on the lower end cover, a shell-side inlet and a shell-side outlet are provided on the shell-side cylinder body. The shell-and-tube fixed-bed reactor further includes: a gas distribution assembly, disposed inside the upper end cover and used for evenly distributing the reaction gas to be reacted at the tube-side inlet; and a lower distribution cylinder, the lower distribution cylinder is located inside the shell-side cylinder body and surrounds the outer circumference of at least part of the reaction tubes. A plurality of through-flow holes are evenly distributed on the side peripheral wall of the lower distribution cylinder for evenly distributing the shell-side medium at the shell-side inlet.

[0006] In some embodiments, the gas distribution assembly includes N flow guiding shells and N flow guiding plate groups, where N is a positive integer greater than 1; the N flow guiding shells are all cylindrical, and the inner diameters of the cross-sections of each flow guiding shell are all set to increase along the air inlet direction; the N flow guiding shells are sleeved in sequence from outside to inside, and the inner diameters of the top surfaces and the bottom surfaces of the N flow guiding shells decrease from outside to inside; the innermost flow guiding shell encloses a central flow guiding channel communicating with the inlet of the tube side, and an outer flow guiding channel communicating with the inlet of the tube side is formed between adjacent two flow guiding shells; the N flow guiding plate groups are divided into one central plate group and N - 1 outer plate groups; the central plate group includes at least one central flow guiding plate, and each central flow guiding plate extends spirally along the air inlet direction and is arranged in the central flow guiding channel; the outer plate groups are arranged in the outer flow guiding channels one by one, and each outer plate group includes at least one outer flow guiding plate, and each outer flow guiding plate extends spirally along the air inlet direction.

[0007] In some embodiments, the N flow guiding shells are all frustum-shaped, the N flow guiding shells are coaxially arranged around the central axis of the inlet of the tube side and their top surfaces are flush, and the heights of the N flow guiding shells increase from outside to inside.

[0008] In some embodiments, the extension lines of the generatrices of the N flow guiding shells respectively intersect the central axis of the inlet of the tube side at the same point, and the difference in the apex angles of the two cones corresponding to adjacent two flow guiding shells is the same as the apex angle value of the cone corresponding to the innermost flow guiding shell.

[0009] In some embodiments, the set of the extension lines of the generatrices of the outermost flow guiding shell towards the upper tube sheet covers the orifices of all the reaction tubes on the upper tube sheet.

[0010] In some embodiments, each of the N flow guiding shells corresponds to one of N cones respectively, the generatrix lengths of the N cones are all the same, and are 1.5 - 2.0 times the inner diameter of the top surface of the outermost flow guiding shell.

[0011] In some embodiments, the number of the central flow guiding plates in the central plate group is the same as the number of the outer flow guiding plates in each outer plate group and is n, where n is a positive integer greater than 1.

[0012] In some embodiments, the n central flow guiding plates are arranged at intervals around the central axis of the inlet of the tube side and are connected to each other on the central axis of the inlet of the tube side, and one side of each central flow guiding plate facing away from the central axis of the inlet of the tube side is connected to the innermost flow guiding shell; each of the outer flow guiding plates in each outer flow guiding channel is arranged at intervals around the central axis of the inlet of the tube side and is connected between adjacent two flow guiding shells for enclosing the outer flow guiding channel.

[0013] In some embodiments, the n central flow guiding plates in the central plate group and the n peripheral flow guiding plates in each peripheral plate group are all rotationally symmetric structures with a rotation angle of 2π / n and the central axis of the tube side inlet as the rotation axis.

[0014] In some embodiments, the set of all cross-sections obtained by intercepting all the central flow guiding plates and all the peripheral flow guiding plates with a plane perpendicular to the central axis of the tube side inlet forms n line segment structures, and the n line segment structures radially extend outward from the same central point.

[0015] In some embodiments, each central flow guiding plate in the central plate group extends from the flush top surface to the bottom end of the innermost flow guiding shell, and each peripheral flow guiding plate in each peripheral plate group extends from the flush top surface to the bottom ends of two adjacent flow guiding shells for enclosing the corresponding peripheral flow guiding channel of the peripheral plate group.

[0016] In some embodiments, a connection fitting is provided at the tube side inlet; the gas distribution assembly further includes a cylindrical extension section connected to the top of the outermost flow guiding shell, an over-flow channel is provided in the extension section, and the over-flow channel is respectively communicated with the tube side inlet, the central flow guiding channel, and each peripheral flow guiding channel; a connecting piece is provided on the extension section, and the connecting piece is fixedly installed on the connection fitting.

[0017] In some embodiments, the shell-and-tube fixed bed reactor further includes an upper distribution cylinder, the upper distribution cylinder is located inside the shell side cylinder body and surrounds at least part of the outer circumference of the reaction tubes; a plurality of the over-flow holes are also evenly distributed on the upper distribution cylinder for evenly distributing the shell side medium flowing towards the shell side outlet.

[0018] In some embodiments, both the upper distribution cylinder and the lower distribution cylinder have connection ends; the connection end of the lower distribution cylinder is provided on the lower tube sheet, and a lower distribution cavity communicated with the shell side inlet is formed by enclosing between the lower distribution cylinder and the shell side cylinder body, and the plurality of over-flow holes on the lower distribution cylinder are all communicated with the lower distribution cavity; the connection end of the upper distribution cylinder is provided on the upper tube sheet, and an upper distribution cavity communicated with the shell side outlet is formed by enclosing between the upper distribution cylinder and the shell side cylinder body, and the plurality of over-flow holes on the upper distribution cylinder are all communicated with the upper distribution cavity.

[0019] In some embodiments, the upper distribution cylinder and the lower distribution cylinder respectively have extension ends opposite to their respective connection ends; the shell side inlet faces the side peripheral wall of the lower distribution cylinder, and the distance between the outer end face of the extension end of the lower distribution cylinder and the center of the shell side inlet is the inner diameter of the shell side inlet.

[0020] In some embodiments, the shell-side outlet faces the lateral peripheral wall of the upper distribution cylinder, and the distance between the outer end face of the outer extension end of the upper distribution cylinder and the center of the shell-side outlet is the inner diameter of the shell-side outlet.

[0021] In some embodiments, the upper distribution cylinder and the lower distribution cylinder are each formed with a plurality of drainage notches at the circumferential edges of their respective connection ends.

[0022] In some embodiments, the inner peripheral walls of the upper distribution cylinder and the lower distribution cylinder are both in contact with the outermost reaction tubes.

[0023] In some embodiments, the plurality of through-flow holes on the upper distribution cylinder are arranged in at least one row along the circumferential direction of the upper distribution cylinder, and the plurality of through-flow holes on the lower distribution cylinder are arranged in at least one row along the circumferential direction of the lower distribution cylinder; each row of the through-flow holes is arranged at equal intervals.

[0024] In some embodiments, the positions of adjacent two rows of the through-flow holes are offset from each other.

[0025] In some embodiments, the number of each row of the through-flow holes on the lower distribution cylinder is not less than 4 times the number of the shell-side inlets.

[0026] In some embodiments, the number of each row of the through-flow holes on the upper distribution cylinder is not less than 4 times the number of the shell-side outlets.

[0027] In some embodiments, the sum of the flow areas of the plurality of through-flow holes on the lower distribution cylinder is not less than 2 times the sum of the flow areas of the shell-side inlets.

[0028] In some embodiments, the sum of the flow areas of the plurality of through-flow holes on the upper distribution cylinder is not less than 2 times the sum of the flow areas of the shell-side outlets.

[0029] In some embodiments, the nominal diameters of both the shell-side inlet and the shell-side outlet are 350 mm.

[0030] In some embodiments, the numbers of both the shell-side inlet and the shell-side outlet are 2 - 4.

[0031] In some embodiments, the tubular fixed-bed reactor further includes a lower baffle plate, and the lower baffle plate is disposed between the lower distribution cylinder and the shell-side cylinder body to enclose and form the lower distribution cavity.

[0032] In some embodiments, the tubular fixed-bed reactor further includes an upper baffle plate, and the upper baffle plate is disposed between the upper distribution cylinder and the shell-side cylinder body to enclose and form the upper distribution cavity.

[0033] One of the technical solutions in the above technical solutions has the following advantages or beneficial effects: By arranging a gas distribution component in the shell-and-tube fixed-bed reactor for evenly distributing the gas to be reacted at the inlet of the tube side, the gas to be reacted can be evenly distributed into multiple substantially identical reaction gas branches and flow into each reaction tube in the reactor, and then react with the internal catalyst. In this way, the catalyst in each reaction tube can be utilized more evenly. By arranging a lower distribution cylinder in the shell-and-tube fixed-bed reactor, the lower distribution cylinder surrounds the outer periphery of at least part of the reaction tubes. At the same time, a plurality of through-flow holes are evenly arranged on the side peripheral wall of the lower distribution cylinder. On the one hand, the shell-side medium at the inlet of the shell side (which can be a medium for heat extraction) can be evenly distributed, that is, the shell-side medium evenly flows into the space between at least part of the reaction tubes from the outer periphery of the lower distribution cylinder, so that the reaction heat in at least part of the reaction tubes can be evenly and timely removed, preventing the occurrence of coking. More importantly, by combining the gas distribution component and the lower distribution cylinder, the reaction gas distribution in each reaction tube in the shell-and-tube fixed-bed reactor can be made uniform, and the temperature of the catalyst bed layer can be made uniform, thereby effectively improving the reaction stability, the conversion rate of the synthesis reaction, and the product yield, achieving a beneficial effect of 1 + 1 > 2.

[0034] Other advantages of this application and the technical effects of the preferred embodiments will be further described in the following specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of this application, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0036] Figure 1 is a longitudinal sectional view of a shell-and-tube fixed-bed reactor provided by at least one embodiment of this application;

[0037] Figure 2 is a longitudinal sectional view of a part of the shell-and-tube fixed-bed reactor provided by at least one embodiment of this application;

[0038] Figure 3 is a three-dimensional schematic view of a gas distribution component provided by at least one embodiment of this application;

[0039] Figure 4 is a front view of a gas distribution component provided by at least one embodiment of this application;

[0040] Figure 5 is a top view of a gas distribution component provided by at least one embodiment of this application;

[0041] Figure 6 is a bottom view schematic diagram of a gas distribution component provided by at least one embodiment of the present application;

[0042] Figure 7 is a longitudinal sectional schematic diagram of a gas distribution component provided by at least one embodiment of the present application;

[0043] Figure 8 is a three-dimensional schematic diagram of N deflector groups (after combination) provided by at least one embodiment of the present application;

[0044] Figure 9 is a front view schematic diagram of N deflector groups (after combination) provided by at least one embodiment of the present application;

[0045] Figure 10 is a top view schematic diagram of N deflector groups (after combination) provided by at least one embodiment of the present application;

[0046] Figure 11 is a sectional schematic diagram of N deflector groups (considering the plate width) provided by at least one embodiment of the present application;

[0047] Figure 12 is a transverse sectional schematic diagram of a shell-and-tube fixed-bed reactor provided by at least one embodiment of the present application;

[0048] Figure 13 is Figure 1 an enlarged view of part A in

[0049] Figure 14 is a planar schematic diagram of a lower distribution cylinder (after expansion) provided by at least one embodiment of the present application;

[0050] Figure 15 is a longitudinal sectional schematic diagram of a lower distribution cylinder provided by at least one embodiment of the present application.

[0051] Among them, the reference numerals in the figure:

[0052] 00: Gas distribution component 1: Deflector shell

[0053] α: Cone apex angle corresponding to the outermost deflector shell 100: Central deflector channel

[0054] R: Cone generatrix length corresponding to the outermost deflector shell 110: Peripheral deflector channel

[0055] 2: Deflector group d: Inner diameter of the top surface of the outermost deflector shell 22: Peripheral plate group 21: Central plate group

[0056] 221: Peripheral deflector 211: Central deflector

[0057] 20: Center point 200: Line segment structure

[0058] 3: Extension section 300: Flow-through channel

[0059] 31: Connecting piece A: Intake direction

[0060] 4: Tube-side inlet 41: Connecting and mating piece

[0061] M: Central axis of the tube-side inlet 52: Lower tube sheet

[0062] 51: Upper tube sheet 7: Upper end cover

[0063] 6: Reaction tube 9: Shell-side cylinder

[0064] 8: Lower end cover 91: Shell-side inlet

[0065] 70: Tube-side outlet 92: Shell-side outlet

[0066] 201: Upper distribution cylinder 202: Lower distribution cylinder

[0067] 1a: Connecting end 1b: Extended end

[0068] 101: Upper distribution cavity 102: Lower distribution cavity

[0069] 500: Flow-through hole 600: Drainage notch

[0070] d1: Inner diameter of the shell-side inlet d2: Inner diameter of the shell-side outlet

[0071] 301: Lower baffle 61: Support plate Detailed implementation manners

[0072] The embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present application, and should not be construed as limiting the present application.

[0073] It should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present application.

[0074] In this application, unless otherwise clearly specified or limited, terms such as "installed", "connected", "linked", "fixed", etc. shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0075] In addition, in the description of this application, the meaning of "a plurality of" is two or more, unless otherwise clearly and specifically limited.

[0076] Take Figures 1 to 15 as an example to illustrate and introduce the shell-and-tube fixed-bed reactor provided in this application. The shell-and-tube fixed-bed reactor provided in this application can be specifically used as a reactor for catalytic hydrogenation of carbon dioxide to methanol, a methanation reactor, etc. in the coal chemical industry field, and there is no limitation here; as Figure 1 shown, the shell-and-tube fixed-bed reactor includes an upper end cover 7, a lower end cover 8, a shell-side cylinder 9 arranged between the upper end cover 7 and the lower end cover 8, an upper tube sheet 51 arranged at the top inside the shell-side cylinder 9, a lower tube sheet 52 arranged at the bottom inside the shell-side cylinder 9, and a plurality of reaction tubes 6 arranged between the upper tube sheet 51 and the lower tube sheet 52. A tube-side inlet 4 is provided on the upper end cover 7, a tube-side outlet 70 is provided on the lower end cover 8, a shell-side inlet 91 and a shell-side outlet 92 are provided on the shell-side cylinder 9; among them, the shell-and-tube fixed-bed reactor further includes a gas distribution assembly 00 and a lower distribution cylinder 202. It should be noted that the gas distribution assembly 00 and the lower distribution cylinder 202 of the present disclosure can also be separately or combinedly arranged on other types of reactors; for the other types of reactors, as long as the structures and functions of the gas distribution assembly 00 and / or the lower distribution cylinder 202 adopted are the same as those of the present disclosure, and the technical problems solved and the technical effects achievable are basically the same, then the other types of reactors should also fall within the protection scope of the present disclosure.

[0077] The gas distribution assembly 00 is arranged inside the upper end cover 7 and is used to evenly distribute the gas to be reacted at the tube-side inlet 4. The gas to be reacted can be a raw material gas or other gases that need to participate in the reaction; by arranging the gas distribution assembly 00 for evenly distributing the gas to be reacted at the tube-side inlet 4 in the shell-and-tube fixed-bed reactor, the gas to be reacted can be evenly distributed into a plurality of substantially identical reaction gas branches and flow into each reaction tube 6 in the shell-and-tube fixed-bed reactor, and then react with the internal catalyst. In this way, the catalysts in each reaction tube 6 can be more evenly utilized.

[0078] The lower distribution tube 202 can be a cylindrical structure, specifically a cylindrical tube, a truncated cone tube, etc., or can be set to other regular or irregular shapes; it is located in the shell-side cylinder 9 and is arranged around the outer periphery of at least part of the reaction tube 6; a plurality of flow holes 500 are evenly arranged on the side circumferential wall of the lower distribution tube 202 to evenly distribute the shell-side medium at the shell-side inlet 91. Among them, the lower distribution tube 202 can be connected to the lower tube plate 52, or it can be fixed on the shell-side cylinder 9 by components, as long as it can ensure that the lower distribution tube 202 is located in the shell-side cylinder 9 and is arranged around the outer periphery of at least part of the reaction tube 6, and the plurality of flow holes 500 thereon can evenly distribute the shell-side medium from the shell-side inlet 91, the lower distribution tube 202 can be arranged near the shell-side inlet 91 and directly facing the shell-side inlet 91, or it can not be directly facing the shell-side inlet 91, as long as the shell-side medium at the shell-side inlet 91 flows to the lower distribution tube 202, it can be evenly distributed by the lower distribution tube 202. By arranging a lower distribution tube 202 in a shell-and-tube fixed bed reactor, the lower distribution tube 202 is arranged around the outer periphery of at least a portion of the reaction tubes 6. At the same time, a plurality of flow holes 500 are evenly distributed on the side wall of the lower distribution tube 202. On the one hand, the shell-side medium (which may be a medium for extracting heat) at the shell-side inlet 91 can be evenly distributed, so that the shell-side medium flows evenly from the outer periphery of the lower distribution tube 202 into at least a portion of the reaction tubes 6 in the lower distribution tube 202, thereby enabling the reaction heat in at least a portion of the reaction tubes 6 to be removed evenly and timely, thereby preventing the occurrence of coking.

[0079] It is worth noting that the present application can make the distribution of the reaction gas in each reaction tube 6 in the shell-and-tube fixed bed reactor uniform and the temperature of the catalyst bed uniform by combining the gas distribution component 00 and the lower distribution tube 202 in the shell-and-tube fixed bed reactor, thereby effectively improving the reaction stability, the conversion rate of the synthesis reaction and the product yield, and obtaining the beneficial effect of 1+1>2.

[0080] In one or more embodiments, the gas distribution assembly 00 may include N guide shells 1 and N guide plate groups 2, wherein N is a positive integer greater than 1; for example, if the gas distribution assembly 00 includes 5 guide shells 1, the number of guide plate groups 2 is also 5.

[0081] The N guide shells 1 are all cylindrical and optionally, the central axis of each guide shell 1 extends along the air inlet direction A, which can be understood as the direction in which the reacted gas flows into the gas distribution assembly 00; the inner diameter of the cross section of each guide shell 1 is set to increase along the air inlet direction A, that is, Figure 2 As shown, if the air intake direction A is from top to bottom, then the inner diameter of the cross section of each guide shell 1 increases from top to bottom. At this time, each guide shell 1 can be understood as a structure that is narrow at the top and wide at the bottom.

[0082] N flow guide shells 1 are sleeved in sequence from outside to inside; if the outermost flow guide shell 1 is the first flow guide shell, the second outermost flow guide shell 1 is the second flow guide shell, and so on, the fact that N flow guide shells 1 are sleeved in sequence from outside to inside can be understood as that the first flow guide shell is sleeved on the outer periphery of the second flow guide shell, the second flow guide shell is sleeved on the outer periphery of the third flow guide shell... the (N - 1)th flow guide shell is sleeved on the outer periphery of the Nth flow guide shell. It should be noted that the first flow guide shell being sleeved on the outer periphery of the second flow guide shell can be further understood as that the second flow guide shell can be completely located inside the first flow guide shell or partially located inside the first flow guide shell. For example, the tops of the two can be set flush while the bottom of the second flow guide shell extends out of the inside of the first flow guide shell, as Figure 4 shown. The other-level flow guide shells 1 can be set in the same way, which will not be elaborated here.

[0083] The inner diameters of the tops of the N flow guide shells 1 decrease from outside to inside, which can be understood as that the inner diameter of the top of the first flow guide shell is greater than that of the second flow guide shell, the inner diameter of the top of the second flow guide shell is greater than that of the third flow guide shell, and so on; and the inner diameters of the bottoms of the N flow guide shells 1 decrease from outside to inside, which can be understood as that the inner diameter of the bottom of the first flow guide shell is greater than that of the second flow guide shell, the inner diameter of the bottom of the second flow guide shell is greater than that of the third flow guide shell, and so on. In this way, between the first flow guide shell and the second flow guide shell, between the second flow guide shell and the third flow guide shell... between the (N - 1)th flow guide shell and the Nth flow guide shell, there are all formed approximately cylindrical intervals, and this interval is the peripheral flow guide channel 110 formed by enclosing between two adjacent flow guide shells 1 and communicating with the tube side inlet 4; the Nth flow guide shell, that is, the innermost flow guide shell 1, can enclose and form a central flow guide channel 100 communicating with the tube side inlet 4. From the above content, it can be seen that the overall structure of this gas distribution assembly 00 is approximately conical sleeve-shaped. After the reaction gas to be treated flows into the N - 1 peripheral flow guide channels 110 through the tube side inlet 4, it can flow out of the N - 1 peripheral flow guide channels 110 obliquely in the direction away from the central axis M of the tube side inlet 4 under the guidance of the corresponding flow guide shell 1. In this way, it helps to shorten the flow path length of the gas reaching the contact member, the gas has a high flow rate and a small pressure drop, the gas can quickly participate in the reaction, the reaction efficiency is accelerated and the reaction cycle is shortened. At the same time, the gas flows out from the multi-layer annular channels, and the gas distribution is uniform, without the problem of insufficient distribution points, and the gas distribution effect is good.

[0084] Among them, the gas distribution assembly 00 can be connected to the tube side inlet 4 through at least one flow guide shell 1, that is, at least one flow guide shell 1 can not only be used for guiding the flow, but also be used for connecting to the tube side inlet 4 to ensure that the gas distribution assembly 00 is stably installed at the tube side inlet 4 of the shell and tube fixed bed reactor.

[0085] N flow guiding plate groups 2 can be divided into a central plate group 21 located in the middle of the gas distribution assembly 00 and N-1 peripheral plate groups 22 located outside the central plate group 21. Among them, the central plate group 21 may include at least one central flow guiding plate 211, and each central flow guiding plate 211 extends spirally along the intake direction A and is arranged in the central flow guiding channel 100. In this way, the gas to be reacted flowing into the central flow guiding channel 100 can flow out spirally under the guidance of the spiral central flow guiding plate 211, thereby increasing the gas flow rate and further enabling the gas to participate in the reaction quickly; at the same time, the spiral central flow guiding plate 211 changes the flow direction of the gas to be reacted flowing into the central flow guiding channel 100, reducing the impact and wear on the upper tube sheet 51 (or other components directly facing the outlet side of the central flow guiding channel 100), and improving the service life of the upper tube sheet 51. The above-mentioned N-1 peripheral plate groups 22 are respectively arranged in N-1 peripheral flow guiding channels 110 one by one, that is, one peripheral flow guiding channel 110 is arranged with one peripheral plate group 22; each peripheral plate group 22 respectively includes at least one peripheral flow guiding plate 221, and each peripheral flow guiding plate 221 extends spirally along the intake direction A. It should be noted that the central flow guiding plate 211 can extend along the entire central flow guiding channel 100 or extend and be arranged at a local position of the central flow guiding channel 100. The specific extension position and spiral size are not limited here; similarly, the peripheral flow guiding plate 221 can extend along the entire corresponding peripheral flow guiding channel 110 or extend and be arranged at a local position of the peripheral flow guiding channel 110. The specific extension position and spiral size are also not limited here. By arranging both the central flow guiding plate 211 and the peripheral flow guiding plate 221 to extend spirally along the intake direction A, the gas flow rate can be increased and the flow path length of the gas reaching the contact member can be shortened.

[0086] As can be seen from the above, the structure of the gas distribution assembly 00 can better control the gas pressure drop and flow rate, and has a good gas distribution effect; at the same time, the gas distribution assembly 00 has a gas outlet only at the bottom of the flow guiding shell 1, which can prompt the gas to be distributed to flow all obliquely downward, so as to participate in the reaction as soon as possible; the structure is simple and easy to produce in batches, and is suitable for reactors with gas participation, such as methanol reactors and methanation reactors in the coal chemical industry field, and has a wide application prospect.

[0087] In some embodiments, such as Figures 3 to 7As shown, the N flow guiding shells 1 are all frustum-shaped. The N flow guiding shells 1 are coaxially arranged around the central axis M of the tube-side inlet 4 with their top surfaces flush. In this way, the reaction gas to be treated can enter the central flow guiding channel 100 and each peripheral flow guiding channel 110 simultaneously, facilitating the uniform distribution of the gas. At the same time, this structure is easy to process and manufacture, and is convenient for the combined assembly of each flow guiding shell 1 of the gas distribution assembly 00. In some embodiments, the heights of the N flow guiding shells 1 increase from the outside to the inside, that is, the height of the flow guiding shell 1 closer to the inside is higher than the height of the flow guiding shell 1 on its outside. Further, it can be understood that the height of the first flow guiding shell is less than the height of the second flow guiding shell, the height of the second flow guiding shell is less than the height of the third flow guiding shell, and so on. This structure enables both the central flow guiding channel 100 and the peripheral flow guiding channels 110 to have sufficient lengths to guide the gas in the channels. At the same time, it can effectively shorten the flow path length of the gas reaching the contact member after distribution, improve the reaction rate of the gas participation, and thus shorten the reaction cycle.

[0088] In some embodiments, referring to Figure 2 , the extension lines of the generatrices of the N flow guiding shells 1 respectively intersect the central axis M of the tube-side inlet 4 at the same point. The difference in the apex angles of the two cones corresponding to two adjacent and corresponding flow guiding shells 1 is the same as the apex angle value of the cone corresponding to the innermost flow guiding shell 1. In other words, if the apex angle of the outermost flow guiding shell 1 is α, the apex angle of the second outermost flow guiding shell 1 is α(N - 1) / N, and so on. The apex angle of the innermost flow guiding shell 1 is α / N. For example, if N is 3, the apex angle of the outermost flow guiding shell 1 is α, the apex angle of the second outermost flow guiding shell 1 is 2α / 3, and the apex angle of the innermost flow guiding shell 1 is α / 3. If N is 5, the apex angle of the outermost flow guiding shell 1 is α, the apex angle of the second outermost flow guiding shell 1 is 4α / 5, and so on. The apex angle of the innermost flow guiding shell 1 is α / 5. This structure is conducive to the distribution and positioning of the gas, with balanced pressure, so that the fluid distribution uniformity is better, and it is easy to process and manufacture. The angles between the flow guiding shells 1 are evenly arranged. When this gas distribution assembly 00 is applied to a large-scale reactor, the gas can be distributed more evenly.

[0089] In some embodiments, the set of extension lines of the generatrices of the outermost flow guiding shell 1 towards the upper tube sheet 51 should be able to cover the orifices of all the reaction tubes 6 on the upper tube sheet 51. That is, when setting the shape of the outermost flow guiding shell 1, it should be based on the criterion that the extension of its generatrix to the upper surface of the upper tube sheet 51 of the shell-and-tube fixed bed reactor can cover all the tube holes of the reaction tubes 6. This structure can enable the gas to flow into each reaction tube 6 along the extension direction of the flow guiding shell 1 after being distributed by the gas distribution assembly 00, and the gas distribution effect is better.

[0090] In some embodiments, the N flow guiding shells 1 respectively correspond to N cones one by one. The generatrix lengths of the N cones are all the same, and are about 1.5 - 2.0 times the inner diameter of the top surface of the outermost flow guiding shell 1. As Figure 2As shown, the generatrix lengths of the N cones corresponding to the N flow guiding shells 1 can be R. If the value of R is set too large, it will hinder the loading of contact parts such as catalysts. In some embodiments, both the gas distribution assembly 00 and the catalyst feed inlet can be arranged on the upper end cover 7 of the shell-and-tube fixed bed reactor. The gas distribution assembly 00 is located between the tube-side inlet 4 and the catalyst feed inlet. The catalyst can be loaded into the reaction tubes 6 from the feed inlet. At this time, if the value of R is larger, the more the catalyst feed inlet will be blocked, which will be more unfavorable for the loading of the catalyst; on the contrary, if the value of R is set too small, the distributed gas will quickly decay in speed due to the increased space, the flow channel will grow, and the flow velocity will decrease, thus being unfavorable for the reaction. Therefore, the setting of this structure and its proportional relationship can facilitate the arrangement of the gas distribution assembly 00 in the shell-and-tube fixed bed reactor, will not hinder the loading of contact parts such as catalysts, and at the same time helps to shorten the flow channel length of the distributed gas to the contact parts, enabling the distributed gas to quickly participate in the reaction and further optimizing the gas distribution effect.

[0091] It should be noted that although the numerical ranges and parameters that describe the broad scope of the present application are approximate values and are limited by "about", the numerical values described in the specific examples are reported as precisely as possible. However, any numerical value inherently contains certain errors, which may be caused by the standard deviations found in their respective test measurements (including the standard deviations found in the measuring instruments). Similarly, it should be understood that any numerical range listed herein is intended to include all sub-ranges contained therein. For example, the range "1.5 - 2.0" is intended to include all sub-ranges between the listed minimum value of 1.5 and the listed maximum value of 2.0 and including this minimum value and maximum value, that is, ranges with a minimum value equal to or greater than 1.5 and a maximum value equal to or less than 2.0. Since the disclosed numerical ranges are continuous, they include every value between the minimum and maximum values, such as 1.6, 1.8, etc. Unless otherwise clearly indicated, the numerical ranges specified in the present application are all approximate values.

[0092] In some embodiments, please also refer to Figure 3 、 Figure 5 and Figure 6, the number of the central flow guiding plates 211 in the central plate group 21 is the same as that of the peripheral flow guiding plates 221 in each peripheral plate group 22 and is n, where n is a positive integer greater than 1. The case where n is 3 is shown in the figure. However, the specific value of n can be selected according to the actual situation and is not uniquely limited here; by setting the number of both the central flow guiding plates 211 and the peripheral flow guiding plates 221 to be multiple, the directions of the gas flowing out after being guided by the multiple central flow guiding plates 211 and the multiple peripheral flow guiding plates 221 can be more diverse, avoiding insufficient gas distribution points and making the gas distribution more uniform; setting the number of the central flow guiding plates 211 and the peripheral flow guiding plates 221 to be the same can further improve the performance of the gas distribution component 00 in evenly distributing the gas.

[0093] In some embodiments, please continue to refer to Figure 3 , Figure 5 and Figure 6 , the n central flow guiding plates 211 are arranged at intervals around the central axis M of the tube-side inlet 4 and are connected to each other on the central axis M of the tube-side inlet 4. One side of each central flow guiding plate 211 facing away from the central axis M of the tube-side inlet 4 is connected to the innermost flow guiding shell 1, that is, the n central flow guiding plates 211 are connected as a whole, and the corresponding connecting line is collinear with the central axis M of the tube-side inlet 4, and the outer sides of the n central flow guiding plates 211 facing away from the central axis M of the tube-side inlet 4 are all connected to the innermost flow guiding shell 1. In this way, the n central flow guiding plates 211 can be stably installed inside the innermost flow guiding shell 1; each of the peripheral flow guiding plates 221 in each peripheral flow guiding channel 110 is arranged at intervals around the central axis M of the tube-side inlet 4 and is connected between two adjacent flow guiding shells 1 used to enclose the peripheral flow guiding channel 110. In this way, each of the peripheral flow guiding plates 221 in each peripheral flow guiding channel 110 can not only play a role in guiding the flow, but also have the role of connecting two adjacent flow guiding shells 1. This structure enables the connection between the flow guiding shells 1 to be realized through the flow guiding plate group 2, without additionally arranging other connecting parts 31, reducing the production cost, with a reasonable structure and ensuring the stability of the overall structure of the gas distribution component 00.

[0094] In some embodiments, reference can be made to Figure 5 and Figure 6, the n central flow guiding plates 211 in the central plate group 21 and the n peripheral flow guiding plates 221 in each peripheral plate group 22 are all rotationally symmetric structures with a rotation angle of 2π / n and the central axis M of the tube side inlet 4 as the rotation axis. As shown in the figure, taking n = 3 as an example, the 3 central flow guiding plates 211 located in the middle are: a rotationally symmetric structure with a rotation angle of 2π / 3 (i.e., 120°) and the central axis M of the tube side inlet 4 as the rotation axis. It can be understood that when the 3 central flow guiding plates 211 rotate 120° around the rotation axis, the obtained structure is the same as the structure of the 3 central flow guiding plates 211 before rotation; at the same time, the 3 peripheral flow guiding plates 221 in each peripheral plate group 22 are also: a rotationally symmetric structure with a rotation angle of 2π / 3 (i.e., 120°) and the central axis M of the tube side inlet 4 as the rotation axis. It can be understood that when the 3 peripheral flow guiding plates 221 belonging to the same peripheral plate group 22 rotate 120° around the rotation axis, the obtained structure is the same as the structure of the 3 peripheral flow guiding plates 221 before rotation. This structure further improves the distribution effect of the gas distribution component 00, and the gas distribution is more uniform. Optionally, the pitch of each central flow guiding plate 211 and each peripheral flow guiding plate 221 can be set to 5 times the diameter of the tube side inlet 4, and the gas distribution effect of this structure is better.

[0095] In some embodiments, reference may be made to Figures 8 to 10 , if the thickness of the flow guiding shell 1, the thickness of the central flow guiding plate 211, and the thickness of the peripheral flow guiding plate 221 are ignored, the combined structure of all the central flow guiding plates 211 and all the peripheral flow guiding plates 221 can form the structure shown in the figure; it can be seen from the figure that this structure is composed of three spiral plate members, specifically a rotationally symmetric structure with a rotation angle of 2π / n (n is 3 in the figure, and the rotation angle is 120° at this time) and the central axis M of the tube side inlet 4 as the rotation axis. In these embodiments, if the thickness of the flow guiding shell 1, the thickness of the central flow guiding plate 211, and the thickness of the peripheral flow guiding plate 221 are taken into account, the set of all cross-sections obtained by intercepting all the central flow guiding plates 211 and all the peripheral flow guiding plates 221 with a plane perpendicular to the central axis M of the tube side inlet 4 can form n line segment structures 200. The n line segment structures 200 radiate outward from the same central point 20, the central point 20 is located on the central axis M of the tube side inlet 4, and the included angle between two adjacent line segment structures 200 is 2π / n; taking Figure 11 as an example, n = 3 in the figure, that is, 3 line segment structures 200 radiate outward from the same central point 20, and the included angle between two adjacent line segment structures 200 is 120°. The central flow guiding plate 211 and the peripheral flow guiding plate 221 are arranged in this way, and the width dimension of each peripheral flow guiding plate 221 at a cross-section is the radial spacing dimension between the two adjacent flow guiding shells 1 connected at this cross-section, and the width dimension of each central flow guiding plate 211 at a cross-section is the inner circle radius dimension of the innermost flow guiding plate at this cross-section. As Figure 6 , Figure 7As shown, if the radial distance between two adjacent flow guiding shells 1 increases from top to bottom, then the width of the outer peripheral flow guiding plates 221 located within these two adjacent flow guiding shells 1 will also increase from top to bottom. This structure makes the structure of the flow guiding plate group 2 easy to process and manufacture, and at the same time facilitates the arrangement of the flow guiding plate group 2 within the flow guiding shell 1, with a reasonable structure.

[0096] As Figure 11 shown, the thicknesses of all the central flow guiding plates 211 and all the outer peripheral flow guiding plates 221 can be set to be the same, or of course, they can also be set to be different according to actual needs.

[0097] In some embodiments, referring to Figure 6 and Figure 7 , each central flow guiding plate 211 in the central plate group 2 extends from the top surface flush position to the bottom end of the innermost flow guiding shell 1, and each outer peripheral flow guiding plate 221 in each outer peripheral plate group 2 extends from the top surface flush position to the bottom ends of the two adjacent flow guiding shells 1 that enclose the corresponding outer peripheral flow guiding channel 110 of this outer peripheral plate group 2. This structure enables the central flow guiding plate 211 and the outer peripheral flow guiding plate 221 to be arranged to extend throughout the channel, which can further increase the gas flow rate and thus improve the reaction efficiency.

[0098] In some embodiments, as Figure 7 shown, the gas distribution assembly 00 further includes a cylindrical extension section 3 connected to the top of the outermost flow guiding shell 1. An overflow channel 300 is provided within the extension section 3, and the overflow channel 300 is respectively connected to the tube side inlet 4, the central flow guiding channel 100, and each outer peripheral flow guiding channel 110; a connecting member 31 is provided on the extension section 3, and the connecting member 31 is fixedly installed on the connecting and mating member 41 at the tube side inlet 4. Optionally, the connecting member 31 and the connecting and mating member 41 are of a bolted flange connection structure, that is, the connecting member 31 and the connecting and mating member 41 can be selected as flange structures, and the two are fixed by bolts; among them, the flange structure can be a flat welding flange or a necked flat welding flange. As Figure 2 shown, the height of the connecting member 31 is H, and the distance from the outer end of the connecting member 31 to the bottom end of the extension section 3 is L. Preferably, it can be set that L≥(H + 25)mm, so as to avoid the welding circumferential seam between the extension section 3 and the outermost flow guiding shell 1 from coinciding with the circumferential seam between the extension section 3 and the connecting member 31, that is, to avoid the coincidence of weld seams and welding defects. Since the gas distribution assembly 00 and the inlet adopt a bolted flange connection structure and do not need to be welded to the inner wall of the shell of the shell-and-tube fixed bed reactor, the gas distribution assembly 00 is easy to replace, and the inner wall of the shell of the shell-and-tube fixed bed reactor will not be damaged when replacing the gas distribution assembly 00.

[0099] In some embodiments, the inner diameter of the top surface of the outermost flow guiding shell 1, the cross-sectional inner diameter of the overflow channel 300, and the diameter of the tube side inlet 4 are all the same. As Figure 2As shown, if the diameter of the tube-side inlet 4 is d, the inner diameter of the cross-section of the flow-through channel 300 is d, and the inner diameter of the top surface of the outermost guide shell 1 is also d. This structure can ensure that the gas flowing out of the tube-side inlet 4 can smoothly enter the flow-through channel 300 and the gas distribution assembly 00, which helps to improve the gas distribution efficiency.

[0100] The following is a summary of the structure of the gas distribution assembly 00: As Figure 2 shown, this tubular fixed-bed reactor adopts the above-mentioned conical sleeve-type gas distribution assembly 00. In some embodiments, the gas distribution assembly 00 may specifically include a connecting piece 31, an extension section 3, a plurality of nested guide shells 1, and a guide plate group 2. More specifically, one end of the extension section 3 is welded to the connecting piece 31, and the other end of the extension section 3 is welded to the top end of the outermost guide shell 1. The plurality of nested guide shells 1 are connected and fixed by the guide plate group 2. The apexes of the generatrices of the plurality of nested guide shells 1 are the same point and are located on the central axis of the gas distribution assembly 00 (i.e., the central axis M of the tube-side inlet 4). The extended lengths of the plurality of nested guide shells 1 should be appropriate so as not to hinder the loading of the catalyst. The connecting and mating part 41 at the tube-side inlet 4 of the conical sleeve-type gas distribution assembly 00 can be fixedly connected by bolts, nuts, and backing plates. The tubular fixed-bed reactor further includes an upper tube sheet 51 and a plurality of reaction tubes 6 on the gas outlet side of the gas distribution assembly 00. The tube orifices of the plurality of reaction tubes 6 are all arranged on the upper surface of the upper tube sheet 51. The gas enters the tubular fixed-bed reactor from the tube-side inlet 4, then flows obliquely downward between the plurality of nested guide shells 1, and then flows to the upper surface of the upper tube sheet 51 of the tubular fixed-bed reactor, flows through the catalyst bed layer in the reaction tube 6 from one end of the reaction tube 6, reacts and then flows out from the other end of the reaction tube 6, and finally is discharged from the reaction gas outlet. This conical sleeve-type gas distribution assembly 00 has a simple structure, is easy to replace, does not damage the reactor shell during replacement, has a short flow path, a high flow rate, and uniform distribution of the raw material gas, can improve the reaction efficiency and shorten the reaction cycle, thereby better controlling the pressure drop and flow rate, and having a better gas distribution state.

[0101] In one or more embodiments, the shell-and-tube fixed-bed reactor further includes an upper distribution cylinder 201. The upper distribution cylinder 201 can be a cylindrical structure, specifically, it can be a cylindrical barrel shape, a frustum-shaped barrel shape, etc., or it can be set to other regular or irregular shapes. The structure of the upper distribution cylinder 201 can be set to be the same as that of the lower distribution cylinder 202. The upper distribution cylinder 201 is located in the shell-side cylinder 9 and surrounds the outer periphery of at least part of the reaction tubes 6. A plurality of flow-through holes 500 are also evenly distributed on the upper distribution cylinder 201 for evenly distributing the shell-side medium flowing towards the shell-side outlet 92. Among them, the upper distribution cylinder 201 can be connected to the upper tube sheet 51 or fixed to the shell-side cylinder 9 through components, as long as it can ensure that the upper distribution cylinder 201 is located in the shell-side cylinder 9 and surrounds the outer periphery of at least part of the reaction tubes 6, and the plurality of flow-through holes 500 on it can evenly distribute the shell-side medium flowing towards the shell-side outlet 92. The upper distribution cylinder 201 can be arranged near the shell-side outlet 92 and face the shell-side outlet 92, or it can be not directly opposite to the shell-side outlet 92, as long as the shell-side medium can flow to the shell-side outlet 92 after being evenly distributed by the upper distribution cylinder 201. A specific implementation manner is that the two distribution cylinders can be respectively arranged at the top and bottom of the shell-side cylinder 9. Of course, the specific arrangement manner can be set according to the actual situation. By arranging the upper distribution cylinder 201 in the shell-and-tube fixed-bed reactor, the upper distribution cylinder 201 surrounds the outer periphery of at least part of the reaction tubes 6. At the same time, a plurality of flow-through holes 500 are evenly distributed on the side peripheral wall of the upper distribution cylinder 201. On the one hand, the shell-side medium between at least part of the reaction tubes 6 inside the upper distribution cylinder 201 can uniformly pass through from the outer periphery of the upper distribution cylinder 201 and flow to the shell-side outlet 92. This structure can also enable the reaction heat in at least part of the reaction tubes 6 to be evenly and timely removed, preventing the occurrence of coking phenomena.

[0102] In one or more embodiments, both the upper distribution cylinder 201 and the lower distribution cylinder 202 have a connection end 1a; the connection end 1a of the lower distribution cylinder 202 is provided on the lower tube sheet 52. A lower distribution cavity 102 communicating with the shell-side inlet 91 is formed by enclosing between the lower distribution cylinder 202 and the shell-side cylinder 9. A plurality of flow-through holes 500 on the lower distribution cylinder 202 communicate with the lower distribution cavity 102; the connection end 1a of the upper distribution cylinder 201 is provided on the upper tube sheet 51. An upper distribution cavity 101 communicating with the shell-side outlet 92 is formed by enclosing between the upper distribution cylinder 201 and the shell-side cylinder 9. A plurality of flow-through holes 500 on the upper distribution cylinder 201 communicate with the upper distribution cavity 101. Between the connection end 1a of the upper distribution cylinder 201 and the upper tube sheet 51, and between the connection end 1a of the lower distribution cylinder 202 and the lower tube sheet 52, connection can be achieved by welding, and of course, other connection methods can also be used, without limitation here. Thus, the lower distribution cylinder 202 is arranged at the bottom of the shell-side cylinder 9, and the shell-side medium can enter the lower distribution cavity 102 through the shell-side inlet 91, and then can enter the central area of the shell-side cylinder 9 through a plurality of flow-through holes 500 on the lower distribution cylinder 202. On the one hand, uniform distribution of the shell-side medium is realized, and on the other hand, it helps to eliminate the flow dead zone in the central area of the shell-side cylinder 9, thereby improving the effective utilization space of the equipment, avoiding excessive reaction of the materials at the dead zone of the shell-and-tube fixed-bed reactor, and further preventing accidents such as coking. The shell-side medium flows from bottom to top. The upper distribution cylinder 201 is arranged at the top of the shell-side cylinder 9. The shell-side medium can enter the upper distribution cavity 101 through a plurality of flow-through holes 500 on the upper distribution cylinder 201, and then is discharged outside the shell-side cylinder 9 through the shell-side outlet 92. This structure can also achieve uniform distribution of the medium, and further ensure uniform distribution of the temperature inside the shell-and-tube fixed-bed reactor.

[0103] It should be noted that the above-mentioned lower distribution cavity 102 and upper distribution cavity 101 can both be an open cavity; for example Figure 13 As shown in the lower distribution cavity 102, the bottom end of the lower distribution cylinder 202 is connected to the lower tube sheet 52, and the top end is a free end. At this time, the lower distribution cavity 102 is an open cavity with an upper opening; of course, the lower distribution cavity 102 can also be a closed cavity, for example Figure 15The lower distribution chamber 102 shown is such that the bottom end of the lower distribution cylinder 202 is also connected to the lower tube sheet 52, and its top end is connected to a plate member (the lower baffle plate 301 in the figure). At this time, the lower distribution chamber 102 is jointly enclosed by the lower distribution cylinder 202, the lower baffle plate 301, the shell-side cylinder 9, and the lower tube sheet 52 to form a relatively enclosed cavity. Among them, the lower baffle plate 301 can be a complete ring structure. At this time, the lower distribution chamber 102 is in a relatively enclosed state. Of course, the lower baffle plate 301 can also be set as at least one sector-ring structure. At this time, the lower distribution chamber 102 has a notch for the shell-side medium to overflow from the top of the lower distribution chamber 102 compared with the former. It should be noted that in addition to setting the lower baffle plate 301 shown in the figure, other structures can also be provided between the lower distribution cylinder 202 and the shell-side cylinder 9 to enclose and form different-shaped lower distribution chambers 102, which is not uniquely defined here. The structure of the upper distribution cylinder 201 can be set with reference to the structure of the lower distribution cylinder 202, and the upper distribution chamber 101 can also be set with reference to the structure of the lower distribution chamber 102, which will not be elaborated here.

[0104] In addition, the thicknesses of the lower distribution cylinder 202 and the upper distribution cylinder 201 can be determined respectively according to the flow velocity and impact force of the medium at the shell-side inlet and outlet. Optionally, when the lower distribution cylinder 202 is made of carbon steel or low-alloy steel, its thickness is not less than 6 mm, and when the lower distribution cylinder 202 is made of stainless steel, its thickness is not less than 4 mm. Of course, the specific thickness value needs to be set according to the actual situation, which is not specifically limited here. The thickness setting of the upper distribution cylinder 201 can also be referred to that of the lower distribution cylinder 202, which will not be elaborated here.

[0105] As can be seen from the above, in the shell-and-tube fixed-bed reactor, the lower distribution cylinder 202 and the upper distribution cylinder 201 are arranged. A plurality of flow-through holes 500 are formed on the circumferential wall of the lower distribution cylinder 202, and a plurality of flow-through holes 500 are formed on the circumferential wall of the upper distribution cylinder. The structure is simple and easy to implement; further, in this internal diversion type liquid distribution structure, the flow-through holes 500 are opened on the lower distribution cylinder 202 or the upper distribution cylinder 201, which can help to achieve the uniform distribution of the shell-side medium on the basis of not damaging the structure of the complete shell-side cylinder 9; and for the shell-side cylinder 9 adopting this liquid distribution structure, except for a few shell-side inlets 91 and shell-side outlets 92, basically no other cumbersome processing is required in cooperation with the shell-side medium distribution, effectively reducing its loss risk and ensuring the structural strength.

[0106] In the above shell-and-tube fixed-bed reactor, the positions of the shell-side inlet 91 and the shell-side outlet 92 can be determined according to the requirements of opening reinforcement and the requirements of the process or piping specialty. The height of the lower distribution cylinder 202 can be determined according to the position of the shell-side inlet 91, and the height of the upper distribution cylinder 201 can be determined according to the position of the shell-side outlet 92. The structures of the upper distribution cylinder 201 and the lower distribution cylinder 202 can be set to be the same. The structure of the lower distribution cylinder 202 will be taken as an example for description below.

[0107] In some specific embodiments of the present application, please refer to Figure 13 and Figure 14 . After the lower distribution cylinder 202 is unfolded, it can be a rectangle, and after being enclosed, it is in the shape of a cylindrical tube. The lower distribution cylinder 202 has an outer extension end 1b opposite to the connection end 1a. The height of the lower distribution cylinder 202 is the shortest distance from the connection end 1a to the outer extension end 1b of the lower distribution cylinder 202. When the side peripheral wall of the lower distribution cylinder 202 is connected to the lower tube sheet 52 at its connection end 1a, it is directly opposite to the shell-side inlet 91. Among them, the side peripheral wall of the lower distribution cylinder 202 being directly opposite to the shell-side inlet 91 can be understood as that the projection point of the center of the shell-side inlet 91 along the medium inflow direction on the lower distribution cylinder 202 should be located between the connection end 1a and the outer extension end 1b of the lower distribution cylinder 202. In this way, the lower distribution cylinder 202 can effectively block the impact of the shell-side medium flowing out from the shell-side inlet 91 on the reaction tube 6. In some embodiments, at this time, the distance between the outer end face of the outer extension end 1b of the lower distribution cylinder 202 and the center of the shell-side inlet 91 is the inner diameter d1 of the shell-side inlet 91. At this time, the height of the lower distribution cylinder 202 should be 1.5 times the inner diameter d1 of the shell-side inlet 91 and the distance between the bottommost end of the shell-side inlet 91 and the lower tube sheet 52. If the distance between the bottommost end of the shell-side inlet 91 and the lower tube sheet 52 is set to 0, the height of the lower distribution cylinder 202 is 1.5 times the inner diameter d1 of the shell-side inlet 91. If the distance between the bottommost end of the shell-side inlet 91 and the lower tube sheet 52 is greater than 0, the height of the lower distribution cylinder 202 is greater than 1.5 times the inner diameter d1 of the shell-side inlet 91. It can be seen that the height of the lower distribution cylinder 202 is at least 1.5 times the inner diameter d1 of the shell-side inlet 91. This structure saves the material of the lower distribution cylinder 202. While achieving cost reduction, it can ensure that all the shell-side medium flowing out from the shell-side inlet 91 can first contact the lower distribution cylinder 202 and then flow into the reaction tubes 6 inside the lower distribution cylinder 202. The fluid distribution effect is better, and the flowing-out medium can be quickly distributed, and the distribution efficiency is higher. Figure 13 The lower distribution cavity 102 shown is an open-top lower distribution cavity 102. In this embodiment, by defining the distance between the outer end face of the outer extension end 1b of the lower distribution cylinder 202 and the center of the shell-side inlet 91 as the inner diameter d1 of the shell-side inlet 91, more than 80% of the shell-side medium flowing out from the shell-side inlet 91 can be distributed between the reaction tubes 6 inside the lower distribution cylinder 202 through the regularly arranged small holes (flow-through holes 500) evenly distributed on the lower distribution cylinder 202, and less than 20% overflows the free end of the lower distribution cylinder 202 and then flows down to between the reaction tubes 6 inside the lower distribution cylinder 202. At this time, the liquid is distributed relatively evenly, and the distribution effect of the lower distribution cylinder 202 is good.

[0108] Similarly, in some embodiments, when the circumferential side wall of the upper distribution cylinder 201 is connected to the upper tube sheet 51 at its connection end 1a, it is directly opposite to the shell-side outlet 92, and the distance between the outer end face of its extension end 1b and the center of the shell-side outlet 92 is the inner diameter d2 of the shell-side outlet 92; the structure of the upper distribution cylinder 201 is similar to the structure and function when the connection end 1a of the lower distribution cylinder 202 is connected to the lower tube sheet 52, and will not be elaborated here.

[0109] In some embodiments of the present application, please refer to Figure 14 , at the circumferential edge, a plurality of drainage notches 600 can be formed at the connection end 1a of the upper distribution cylinder 201 and the connection end 1a of the lower distribution cylinder 202, which can facilitate the drainage and exhaustion of the shell-side medium inside the upper distribution cylinder 201 and the lower distribution cylinder 202. After being discharged to the upper distribution chamber 101 and the lower distribution chamber 102, it can be further discharged outside the tubular fixed-bed reactor. Among them, for the convenience of processing, the drainage notches 600 can be set as semi-circular notches, rectangular notches, triangular notches, etc. Of course, it is not limited thereto and can be set according to actual needs.

[0110] In some embodiments of the present application, please continue to refer to Figure 14 , for the convenience of processing and manufacturing, the flow-through holes 500 on the upper distribution cylinder 201 and the lower distribution cylinder 202 can be set as regular holes such as circular holes, rectangular holes, waist-shaped holes or oval holes. Of course, they can also be set as irregular hole structures, and other structures (such as various-shaped through grooves) that can realize the penetration of the shell-side medium through the lower distribution cylinder 202 should also fall within the protection scope of the present application; the shapes of the flow-through holes 500 on the upper distribution cylinder 201 and the lower distribution cylinder 202 can be the same or different and can be set according to needs.

[0111] In one or more embodiments, the inner circumferential walls of the upper distribution cylinder 201 and the lower distribution cylinder 202 are both in contact with the outermost reaction tubes 6. Please refer to Figure 1, the lower distribution cylinder 202 can be disposed around the outer periphery of all the reaction tubes 6 within the shell-side cylinder 9, and its inner peripheral wall abuts against the outermost reaction tube 6 within the shell-side cylinder 9; this structure enables the lower distribution cylinder 202 to be looped around the periphery of all the reaction tubes 6, effectively preventing the impact of the shell-side medium on the reaction tubes 6 to protect the reaction tubes 6; by abutting the outermost reaction tube 6 against the inner peripheral wall of the lower distribution cylinder 202, the structural strength and anti-deformation ability of the lower distribution cylinder 202 can be effectively improved; this structure is reasonable and will not affect the original layout of the reaction tubes 6 and the support of the reaction tubes 6 inside the shell-side cylinder 9. At the same time, it will not affect the original manufacturing sequence and difficulty of the shell-and-tube fixed-bed reactor. The inner peripheral wall of the upper distribution cylinder 201 abuts against the outermost reaction tube 6, and its structure and function are similar, so details will not be elaborated here. It should be noted that the reaction tubes 6 of this shell-and-tube fixed-bed reactor can be enhanced heat transfer tubes such as corrugated tubes, finned tubes, threaded tubes, spiral groove tubes, and high-brightness tubes to increase the flow rate and heat transfer of the shell-side medium.

[0112] In one or more embodiments, the multiple flow-through holes 500 on the upper distribution cylinder 201 are arranged in at least one row along the circumferential direction of the upper distribution cylinder 201, and the multiple flow-through holes 500 on the lower distribution cylinder 202 are arranged in at least one row along the circumferential direction of the lower distribution cylinder 202; the arrangement mode of the multiple flow-through holes 500 on the upper distribution cylinder 201 is similar to that of the multiple flow-through holes 500 on the lower distribution cylinder 202. Only the arrangement of the multiple flow-through holes 500 on the lower distribution cylinder 202 will be described below. As Figure 14 shown, the multiple flow-through holes 500 are arranged in at least one row along the circumferential direction of the lower distribution cylinder 202 ( Figure 14 3 rows of flow-through holes 500 are shown), and the positions of adjacent two rows of flow-through holes 500 are staggered from each other; this structure can further improve the medium distribution effect and distribution efficiency of the lower distribution cylinder 202. Further referring to Figure 14 , each row of flow-through holes 500 can include multiple flow-through holes 500, and the multiple flow-through holes 500 can be arranged at equal intervals. In addition, in at least one row of flow-through holes 500 on the lower distribution cylinder 202, there can be a row of flow-through holes 500 such that the central axis of the shell-side inlet 91 is located in the plane where this row of flow-through holes 500 is located, that is, the center of each flow-through hole 500 in this row is at the same height as the center of the shell-side inlet 91; this structure can help the shell-side medium flowing out from the shell-side inlet 91 to be quickly and evenly distributed, improving the distribution efficiency.

[0113] In one or more embodiments, the number of each row of flow-through holes 500 on the lower distribution cylinder 202 is not less than 4 times the number of the shell-side inlets 91. In one or more embodiments, the number of each row of flow-through holes 500 on the upper distribution cylinder 201 is not less than 4 times the number of the shell-side outlets 92. This structure can ensure that the shell-side medium can quickly pass through the lower distribution cylinder 202 and the upper distribution cylinder 201, achieving uniform distribution, thus having a high distribution efficiency, with a reasonable structure and being easy to implement.

[0114] In one or more embodiments, the sum of the flow areas of the multiple flow-through holes 500 on the lower distribution cylinder 202 is not less than 2 times the sum of the flow areas of the shell-side inlets 91. In one or more embodiments, the sum of the flow areas of the multiple flow-through holes 500 on the upper distribution cylinder 201 is not less than 2 times the sum of the flow areas of the shell-side outlets 92; specifically, the nominal diameters of the shell-side inlet 91 and the shell-side outlet 92 can both be 350 mm. Further, the number of the shell-side inlets 91 and the shell-side outlets 92 can both be 2 - 4. This structure can also ensure that the shell-side medium can quickly pass through the lower distribution cylinder 202 and the upper distribution cylinder 201, achieving uniform distribution, thus having a high distribution efficiency.

[0115] In some embodiments of the present application, please refer to Figure 15 , the shell-and-tube fixed-bed reactor may further include an upper baffle and a lower baffle 301. The two baffles are respectively connected to the lower distribution cylinder 202 and the upper distribution cylinder 201. Their structures and functions are similar, so the following will take the connection between the lower baffle 301 and the lower distribution cylinder 202 as an example for introduction. The lower baffle 301 can be arranged between the lower distribution cylinder 202 and the shell-side cylinder 9 to enclose a lower distribution cavity 102. The lower baffle 301 can be connected to the lower distribution cylinder 202, or to the shell-side cylinder 9, or of course to both. The connection method can be a fixed connection or a detachable connection, specifically including but not limited to welding, clamping, screwing, electromagnetic connection, etc.; the setting of the connection method should consider the convenience of operation and the disassembly and assembly of the internal components of the reactor (such as the support plate 61, the baffle plate, etc.). Among them, the inner side of the lower baffle 301 can be connected to the outer extension end 1b of the lower distribution cylinder 202, or to other parts of the lower distribution cylinder 202; the lower baffle 301 can be set as a regular structure such as a ring shape or a sector ring shape, or as other irregular structures; it can be arranged horizontally, obliquely, or in a concave-convex manner; it should be noted that the specific structure, shape, baffle area, etc. of the lower baffle 301 are not specifically limited. The lower baffle 301 may not be provided with hole grooves or other structures, or may be similar to the lower distribution cylinder 202, and a plurality of through holes for fluid passing are uniformly arranged, which is not limited here. By setting the lower baffle 301, it can be ensured that the shell-side medium overflows from its top as little as possible or not at all in the lower distribution cavity 102, and then the shell-side medium can be uniformly distributed as much as possible through the lower distribution cylinder 202, thereby improving the distribution effect of the lower distribution cylinder 202.

[0116] In one or more embodiments, the structure of the shell-and-tube fixed bed reactor to support the reaction tube 6 may be a support plate 61 or a baffle. This structure may be a structure well known to those skilled in the art, and will not be described in detail here because it does not belong to the core improvement part of the present application.

[0117] It is worth noting that the support plate 61 or baffle can be improved to arrange a small number of reaction tubes 6 or no reaction tubes 6 near the circumference of the shell-side cylinder 9, so that the outermost reaction tube 6 can be arranged slightly inward to provide sufficient space for the arrangement of the upper distribution tube 201 and the lower distribution tube 202; at the same time, the area without tubes can also meet the needs of shell-side medium circulation, which can effectively reduce the shell-side pressure drop. The multiple support plates 61 arranged on the reaction tube 6 can be fully supported by the support plates 61 with holes between the tube holes. This structure can not only increase the rigidity of the reaction tube 6 and prevent the vibration of the reaction tube 6, but also the shell-side medium flows axially through the support plates 61, there is no shell-side flow dead zone, and the catalyst bed temperature is uniform.

[0118] The following summary is made for the lower distribution tube 202 and the upper distribution tube 201: The shell-side cylinder 9 using the lower distribution tube 202 and the upper distribution tube 201 does not need to be processed in conjunction with the shell-side medium distribution except for a few shell-side inlets 91 and shell-side outlets 92, which effectively reduces the risk of loss and ensures the structural strength. At the same time, by using the lower distribution tube 202 or the upper distribution tube 201, the shell-and-tube fixed bed reactor can reduce the number of shell-side inlets 91 or shell-side outlets 92; for example, when the lower distribution tube 202 is not provided, the formation of the shell-side inlet 91 may require 6 to 8 pipes with a nominal diameter of 300 mm; when the lower distribution tube 202 is provided, the formation of the shell-side inlet 91 may only require 2 to 4 pipes with a nominal diameter of 350 mm. The reduction in the number of shell-side inlets 91 and shell-side outlets 92 is conducive to the piping, manufacturing, heat treatment, transportation and other operations of the shell-and-tube fixed bed reactor. On the contrary, when the number of shell-side inlet 91 and shell-side outlet 92 is large, not only the difficulty of manufacturing and piping of the reactor is increased, but also the width and height of the reactor are expanded, increasing the difficulty of its heat treatment and transportation. When the number of shell-side inlet 91 and shell-side outlet 92 is small, it is not only conducive to the piping and manufacturing of the reactor, but also the shell-side inlet 91 and shell-side outlet 92 can be arranged in the height direction, thereby reducing the width of the reactor, which is conducive to the heat treatment and transportation of the reactor. By adopting the lower distribution tube 202 and / or the upper distribution tube 201 of the inner flow-guiding type, the shell-side medium of the tube-in-tube fixed bed distributor of the present application is evenly distributed, and the catalyst bed temperature is uniform.

[0119] The following summary is made for the shell-and-tube fixed-bed reactor: At present, the reactors for catalytic hydrogenation of carbon dioxide to methanol in China are still in the research and development and pilot-plant stages, and there are few applications of industrialized mature devices. Therefore, the existing reactors for catalytic hydrogenation of carbon dioxide to methanol also adopt the reactors for hydrogenation of syngas to methanol. The heat release during the methanol formation reaction process is large. If the heat is not removed in time, the temperature inside the reactor will be very high, which will affect the use function of the catalyst. At the same time, the reaction temperature inside the reactor cannot be too low, otherwise it is not conducive to the forward progress of the reaction and affects the methanol yield. During the methanol synthesis process, the ideal reactor should be able to maintain as small a temperature difference as possible for the catalyst, that is, to reach an isothermal or nearly isothermal state. The shell-and-tube fixed-bed reactor provided in this application is equipped with a gas distribution component and a lower distribution cylinder, which can effectively ensure the isothermal or nearly isothermal state of the catalyst, thereby improving the stability of the catalytic hydrogenation of carbon dioxide to methanol and the product yield. Therefore, the shell-and-tube fixed-bed reactor provided in this application is suitable for use as a reactor for catalytic hydrogenation of carbon dioxide to methanol. By adopting the shell-and-tube fixed-bed reactor proposed in this application and combining the gas distribution component and the lower distribution cylinder, the gas distribution at the tube-side inlet of the shell-and-tube fixed-bed reactor can be made uniform and the flow rate can be high, the reaction gas distribution in each reaction tube inside is uniform, the heat transfer medium distribution in the shell side is uniform, and the temperature of the catalyst bed layer is uniform, thereby effectively improving the reaction stability, the conversion rate of the synthesis reaction and the product yield, and obtaining a beneficial effect of 1 + 1 > 2. The overall structure of the shell-and-tube fixed-bed reactor is simple and compact, convenient for manufacturing, transportation and installation, and the catalyst is easy to load and unload. If the enhanced heat transfer type reaction tube 6 and the fully supported support plate 61 are used in the shell-and-tube fixed-bed reactor, the heat transfer effect and rigidity of the reaction tube 6 can be further improved, and there is no dead zone in the shell-side flow. At this time, the reaction stability and product yield of the shell-and-tube fixed-bed reactor are more ideal.

[0120] Obviously, the above embodiments of the present application are merely examples for clearly illustrating the present application, and are not intended to limit the implementation manners of the present application. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A tubular fixed bed reactor, comprising an upper end cover, a lower end cover, a shell-side cylinder arranged between the upper end cover and the lower end cover, an upper tube sheet arranged at the top of the shell-side cylinder, a lower tube sheet arranged at the bottom of the shell-side cylinder, and a plurality of reaction tubes arranged between the upper tube sheet and the lower tube sheet, wherein the upper end cover is provided with a tube-side inlet, the lower end cover is provided with a tube-side outlet, and the shell-side cylinder is provided with a shell-side inlet and a shell-side outlet, characterized in that: The tubular fixed bed reactor further comprises: A gas distribution assembly, disposed inside the upper end cover and used to evenly distribute the reacted gas at the inlet of the tube pass; and The lower distribution tube is located in the shell-side cylinder and surrounds at least part of the outer circumference of the reaction tube; a plurality of flow holes are evenly arranged on the side wall of the lower distribution tube to evenly distribute the shell-side medium at the shell-side inlet.

2. The tubular fixed bed reactor according to claim 1, characterized in that: The gas distribution assembly includes N guide shells and N guide plate groups, where N is a positive integer greater than 1; The N guide shells are all cylindrical, and the inner diameter of the cross section of each guide shell is set to increase along the air intake direction; the N guide shells are sequentially sleeved from outside to inside, and the inner diameters of the top surfaces and bottom surfaces of the N guide shells decrease from outside to inside respectively; the innermost guide shells enclose a central guide channel connected to the tube side inlet, and the adjacent two guide shells enclose a peripheral guide channel connected to the tube side inlet; The N guide plate groups are divided into a central plate group and N-1 peripheral plate groups; the central plate group includes at least one central guide plate, each of which extends spirally along the air intake direction and is arranged in the central guide channel; the peripheral plate groups are arranged in the peripheral guide channel one by one, each of which includes at least one peripheral guide plate, each of which extends spirally along the air intake direction.

3. The tube-in-tube fixed bed reactor according to claim 2, characterized in that: The N flow guide shells are all in a truncated cone shape, are coaxially arranged around the central axis of the tube inlet and have flush top surfaces, and the heights of the N flow guide shells increase from outside to inside.

4. The tube-in-tube fixed bed reactor according to claim 3, characterized in that: The generatrix extension lines of the N guide shells intersect with the central axis of the tube pass inlet at the same point respectively, and the difference between the vertex angles of the two cones corresponding to two adjacent guide shells is the same as the vertex angle value of the cone corresponding to the innermost guide shell; and / or, the set of extension lines of the generatrix of the outermost guide shell toward the upper tube plate covers the tube openings of all the reaction tubes on the upper tube plate.

5. The tube-in-tube fixed bed reactor according to claim 4, characterized in that: The N guide shells correspond to N cones respectively, and the generatrix lengths of the N cones are the same and are 1.5-2.0 times the inner diameter of the top surface of the outermost guide shell.

6. The tubular fixed bed reactor according to any one of claims 3 to 5, characterized in that: The number of the central guide plates in the central plate group is the same as the number of the peripheral guide plates in each of the peripheral plate groups and is n, where n is a positive integer greater than 1.

7. The tube-in-tube fixed bed reactor according to claim 6, characterized in that: The n central guide plates are arranged at intervals around the central axis of the tube-side inlet and connected to each other on the central axis of the tube-side inlet, and the side of each central guide plate facing away from the central axis of the tube-side inlet is connected to the innermost guide shell; each of the peripheral guide plates in each peripheral guide channel is arranged at intervals around the central axis of the tube-side inlet and connected between two adjacent guide shells used to enclose the peripheral guide channel.

8. The tube-in-tube fixed bed reactor according to claim 7, characterized in that: The n central guide plates in the central plate group and the n peripheral guide plates in each peripheral plate group are all rotationally symmetrical structures with a rotation angle of 2π / n and a central axis of the tube inlet as the rotation axis.

9. The tube-in-tube fixed bed reactor according to claim 8, characterized in that: The collection of all cross sections of all the central guide plates and all the peripheral guide plates cut by the same plane perpendicular to the central axis of the tube inlet constitutes n line segment structures, and the n line segment structures extend radially outward from the same center point.

10. The tubular fixed bed reactor according to any one of claims 3 to 5, characterized in that: Each central guide plate in the central plate group extends from the top surface flush to the bottom end of the innermost guide shell, and each peripheral guide plate in each peripheral plate group extends from the top surface flush to the bottom ends of two adjacent guide shells for enclosing the peripheral guide channel corresponding to the peripheral plate group.

11. The tubular fixed bed reactor according to any one of claims 2 to 5, characterized in that: A connecting fitting is provided at the pipe side inlet; the gas distribution assembly also includes a cylindrical extension section connected to the top of the outermost guide shell, and a flow channel is provided in the extension section, and the flow channel is respectively connected to the pipe side inlet, the central guide channel and each of the peripheral guide channels; a connecting piece is provided on the extension section, and the connecting piece is fixedly mounted on the connecting fitting.

12. The tube-in-tube fixed bed reactor according to claim 1, characterized in that: The tube-in-tube fixed bed reactor also includes an upper distribution tube, which is located in the shell-side cylinder and surrounds at least part of the outer circumference of the reaction tube; a plurality of flow holes are also evenly distributed on the upper distribution tube to evenly distribute the shell-side medium flowing to the shell-side outlet.

13. The tube-in-tube fixed bed reactor according to claim 12, characterized in that: The upper distribution tube and the lower distribution tube both have a connection end; The connection end of the lower distribution tube is arranged on the lower tube plate, the lower distribution tube and the shell side cylinder body enclose a lower distribution cavity connected to the shell side inlet, and the multiple flow holes on the lower distribution tube are all connected to the lower distribution cavity; The connection end of the upper distribution tube is arranged on the upper tube plate, and the upper distribution tube and the shell side cylinder body enclose an upper distribution cavity connected with the shell side outlet, and the multiple flow holes on the upper distribution tube are all connected with the upper distribution cavity.

14. The tube-in-tube fixed bed reactor according to claim 13, characterized in that: The upper distribution tube and the lower distribution tube respectively have an extension end opposite to the respective connection end; The shell-side inlet is directly opposite to the side circumferential wall of the lower distribution tube, and the distance between the outer end surface of the extended end of the lower distribution tube and the center of the shell-side inlet is the inner diameter of the shell-side inlet; and / or, The shell-side outlet is directly opposite to the side circumferential wall of the upper distribution tube, and the distance between the outer end surface of the extended end of the upper distribution tube and the center of the shell-side outlet is the inner diameter of the shell-side outlet.

15. The tube-in-tube fixed bed reactor according to claim 13, characterized in that: The upper distribution tube and the lower distribution tube are respectively formed with a plurality of drainage notches at the circumferential edges of the respective connection ends.

16. The tube-in-tube fixed bed reactor according to claim 12, characterized in that: The inner circumferential wall of the upper distribution tube and the inner circumferential wall of the lower distribution tube are both in contact with the outermost reaction tube.

17. The tubular fixed bed reactor according to any one of claims 12 to 16, characterized in that: The multiple flow holes on the upper distribution tube are arranged in at least one row along the circumference of the upper distribution tube, and the multiple flow holes on the lower distribution tube are arranged in at least one row along the circumference of the lower distribution tube; the flow holes in each row are arranged at equal intervals, and / or the positions of the flow holes in two adjacent rows are staggered.

18. The tube-in-tube fixed bed reactor according to claim 17, characterized in that: The number of the flow holes in each row on the lower distribution tube is not less than 4 times the number of the shell-side inlets; and / or, the number of the flow holes in each row on the upper distribution tube is not less than 4 times the number of the shell-side outlets; and / or, The sum of the flow areas of the plurality of flow holes on the lower distribution tube is not less than twice the sum of the flow areas of the shell side inlet; and / or, the sum of the flow areas of the plurality of flow holes on the upper distribution tube is not less than twice the sum of the flow areas of the shell side outlet; and / or, The nominal diameters of the shell side inlet and the shell side outlet are both 350 mm; and / or, The number of the shell side inlet and the number of the shell side outlet are both 2-4.

19. The tubular fixed bed reactor according to any one of claims 13 to 15, characterized in that: The tubular fixed bed reactor further comprises a lower baffle plate, which is arranged between the lower distribution tube and the shell-side cylinder to enclose and form the lower distribution chamber; and / or, The tube-in-tube fixed bed reactor further comprises an upper baffle plate, which is arranged between the upper distribution cylinder and the shell-side cylinder to enclose and form the upper distribution chamber.

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