Tandem pipe reactor with spirally distributed pipes

Abstract

The utility model relates to the technical field of petrochemical equipment, in particular to a serial pipe reactor with spirally distributed pipes, which comprises a plurality of straight sleeves and a plurality of bent pipes, each straight sleeve comprises an inner pipe and an outer pipe, and the inner pipe is arranged in the outer pipe in a penetrating manner to form an annular straight jacket flow channel; the inner pipes of the plurality of straight sleeves are connected in series through the bent pipe to form a medium flow channel for conveying and reacting reaction materials, and the straight jacket flow channels of the plurality of straight sleeves are connected in series to form a cooling flow channel for conveying a cooling medium. The straight sleeves are arranged in two or more rows, and the two ends of each bent pipe are connected with the ends of the straight sleeves in different rows respectively, so that the straight sleeves and the bent sleeves are distributed in a spiral shape. The overall structure is more compact, the height and the gravity center are lowered when the device is horizontally arranged, the device can be transported to an installation site after being integrally assembled in a manufacturer, hoisting is convenient, the site construction period is shortened, and the site construction safety is improved. The occupied area of the whole structure is reduced, and the space needed by whole hoisting during construction and installation is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of petrochemical equipment, in particular to a spirally arranged pipe-in-pipe reactor suitable for a large-scale polymerization pipe-in-pipe reactor and a prepolymerization reactor. Background Art

[0002] Polypropylene and polyethylene are the most produced and consumed types of general synthetic resins. There are three production technologies for them, namely slurry polymerization, gas phase polymerization and solution polymerization. Slurry process is the main method, which can be divided into stirred tank reactor and series tube reactor according to the reactor form.

[0003] The traditional series pipe reactor is mainly composed of several straight sleeves, outer elbows, inner elbows, mounting supports and connecting beams, depending on the production capacity. Every two straight tube cylinders and two elbows form a cycle. Because the polymerization reaction will generate heat, the reaction heat is taken away by the cooling water in the jacket. The outer tube of the straight sleeve is provided with a corrugated expansion joint, a mounting support and a support beam seat. The inner elbow is connected to the inner tube of the straight sleeve through a flange to connect the straight sleeve into a whole process. The outer side of the inner elbow is covered with an outer elbow, so as to form a ring-shaped curved jacket flow channel between the two. The jacket of the straight sleeve and the curved jacket flow channel are connected to a whole process through the jacket connecting pipe on the side. The connecting beam is connected to the support beam seat by bolts to combine the straight sleeve into a three-dimensional frame. The string pipe reactor is supported by multiple foundations, that is, each straight sleeve has its own mounting support. The errors of the length, axis position, orientation, elevation, spacing, etc. of the straight sleeve, as well as the parallelism of the straight sleeve, the verticality of the flange, the manufacturing error of the elbow, and many other factors will affect the sealing performance of the string pipe installation at the same time. The installation of the string pipe reactor can be divided into two types: upright and inclined. The latter occupies a slightly larger area, and its overall structure is more stable than the former.

[0004] For example, Figure 1As shown, a vertically installed series tube reactor is mainly composed of six straight sleeves (R1, R2, ... R6), five 180° large elbows (A1, A2, A3, and two elbows at the bottom), and a 90° elbow connected in sequence to form a circulation whole, and is located on a higher platform foundation through five outer elbows connected to the outer tube at the inner elbow. An axial flow pump is provided at the inner elbow at the bottom of the series tube. The reaction material enters the series tube reactor from the reaction material inlet 1A, is stirred and circulated in the tube under the drive of the axial flow pump, reacts to form slurry polypropylene under the action of the catalyst, and is discharged from the reaction material outlet 1B into the granulation system; the cooling medium enters from the cooling medium inlet of the jacket flow channel and flows out to the cooling medium outlet of the jacket flow channel. Six mounting supports are located at the lower part of each straight sleeve R1, R2, R3, R4, R5, and R6. The jackets are connected by five jacket connecting pipes. The cooling water in the jacket takes away the heat released by the reaction in the inner tube through the partition wall to maintain the normal operation of the reaction process. In order to coordinate the difference in thermal expansion displacement caused by the different temperatures of the inner and outer tubes, the jacket is attached with an expansion joint; the jacket is also attached with an expansion joint, a support beam seat and a support. The adjacent jackets are connected by steel sections to form several space platforms.

[0005] There are further improvements:

[0006] With the scarcity of oil resources, in order to adapt to the huge market demand and development of polyolefin special materials, new and more stringent requirements have been put forward for the structure, production capacity and quality of string tube reactor equipment. Chemical companies hope to reduce costs and improve the market competitiveness of prices through the scale effect of high production capacity. The overall structural dimensions of the string tube reactor are getting larger and larger.

[0007] The first problem is that the spacing between all straight sleeves is restricted by the bending diameter of the connecting elbows at both ends and cannot be changed. The footprint of the overall structure increases, and the space required for overall lifting during construction and installation increases.

[0008] The second problem is that the modal analysis of the overall structure under wind load and seismic load shows that its deformation and displacement degree increases, and the strengthening structural materials such as connecting beams increase significantly.

[0009] The third question is from Figure 1 From the lateral directions, it can be seen that the traditional connection and reinforcement structure includes horizontally installed connection beams and inclined bracing beams, which have a good effect on resisting the bending deformation of the overall structure, but there is room for improvement in resisting the torsional deformation of the overall structure.

[0010] The fourth question is from Figure 1 From the top view, it can be seen that the traditional connection and reinforcement structure is square or rectangular, lacking inclined beams to improve stability.

[0011] The fifth problem is that all straight sleeves are subject to strong horizontal wind loads. In the direction of the strongest main wind, the front straight sleeve cannot shield the back straight sleeve, and a large amount of material is used to repeatedly resist the repeated effects of the same load.

[0012] In summary, in order to quickly adapt to the current market environment of large demand for high-capacity and large-structure string tube reactors in the new construction and expansion of petrochemical industry, meet the needs of capacity expansion, capacity expansion and upgrading of traditional string tube reactors, and high-capacity polypropylene production capacity of more than 600,000 tons / year, the development of new-structure high-capacity string tube reactors has far-reaching and significant industrial and economic significance. Summary of the invention

[0013] In view of all or part of the above-mentioned technical problems existing in the prior art, the utility model provides a series of tube reactors with spiral tube layout.

[0014] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0015] A spirally arranged tube-in-tube reactor is provided, comprising a plurality of straight tubes and a plurality of curved tubes, each straight tube comprising an inner tube and an outer tube, the inner tube being inserted into the outer tube to form an annular straight jacket flow channel; the inner tubes of the plurality of straight tubes are connected in series via curved tubes to form a medium flow channel for conveying reaction materials and reacting, and the straight jacket flow channels of the plurality of straight tubes are connected in series to form a cooling flow channel for conveying cooling medium, and sealing structures are provided at both ends of the straight jacket flow channel to seal the two ends of the straight jacket flow channel; the reactor is characterized in that: the plurality of straight tubes are arranged in an array, and the number of the arranged rows is more than two, and the two ends of each curved tube are respectively connected to the ends of the straight tubes in different rows, so that the plurality of straight tubes and the plurality of curved tubes are arranged in a spiral shape.

[0016] As a further optional solution, the series pipe reactor further comprises a plurality of jacketed connecting pipes;

[0017] The straight jacket flow passages of multiple straight sleeves are connected in series as follows: the elbow is a single-layer pipe, and the two ends of the jacket connecting pipe are connected to the outer pipe side walls of different straight sleeves and connected to the corresponding straight jacket flow passages, so that the straight jacket flow passages of two adjacent straight sleeves are directly connected through the jacket connecting pipe;

[0018] Alternatively, each curved pipe is a double-layer pipe including an outer elbow and an inner elbow, the outer elbow is sleeved on the outer side of the inner elbow to form an annular curved jacket flow channel; the inner pipes of different straight sleeves are connected in series via the inner elbow to form the medium flow channel; the two ends of the curved jacket flow channel are respectively provided with sealing structures to seal the two ends of the curved jacket flow channel; one end of the jacket connecting pipe is connected to the outer pipe side wall of the straight sleeve and connected to the straight jacket flow channel, and the other end of the jacket connecting pipe is connected to the outer elbow side wall of the curved pipe and connected to the curved jacket flow channel, so that the straight jacket flow channels of two adjacent straight sleeves are connected via the jacket connecting pipe and the curved jacket flow channel.

[0019] As a further optional solution, the spiral direction of the spiral pipe arrangement is a preset windward direction.

[0020] As a further optional solution, along the pitch direction of the spiral pipe arrangement, the distance between the centers of two adjacent straight sleeves is H, the outer diameter of the straight sleeve is L, and H / L≤4.5.

[0021] As a further optional solution, the outer side of the straight sleeve is wrapped with a thermal insulation layer, and L is the outer diameter of the thermal insulation layer.

[0022] As a further optional solution, a support is respectively provided in the middle of each straight sleeve, and the supports of the straight sleeves in the same row are connected to the same connecting beam.

[0023] As a further optional solution, the straight sleeves in the same row are arranged close to each other, and a lining plate is provided between the supports of two adjacent straight sleeves to connect them.

[0024] As a further optional solution, a horizontal beam arranged horizontally and a diagonal bracing beam arranged obliquely are provided between every three adjacent straight sleeves, and the horizontal beam and the diagonal bracing beam are in a triangular shape in the longitudinal projection.

[0025] As a further alternative, the straight bushings in different rows are arranged in alignment or staggered.

[0026] As a further optional solution, the pitch of the spiral pipe arrangement is a single value or a variable value.

[0027] Beneficial effects of the utility model:

[0028] The spiral pipe series reactor of the utility model is not only suitable for the production of polyethylene and polypropylene in petrochemical industry, but also suitable for other production processes in petrochemical industry. It has the following advantages:

[0029] (1) The overall structure is more compact, and the height and center of gravity are lowered when lying down, which is conducive to transportation to the installation site after overall assembly in the manufacturing plant, and realizes the overall one-time lifting during construction and installation, greatly shortening the on-site construction period and improving the safety of on-site construction.

[0030] (2) The floor space occupied by the overall structure is reduced, and the space required for overall lifting during construction and installation is reduced.

[0031] (3) By changing the combination of each straight sleeve into a sequential series spiral structure and changing the arrangement spacing of each straight sleeve in the main wind direction, the front straight sleeve can cover the back straight sleeve, reducing the effect of wind load on the back straight sleeve structure, improving equipment reliability and extending equipment life.

[0032] Further:

[0033] (4) The connecting and reinforcing structure includes horizontal beams installed horizontally and diagonal bracing beams arranged obliquely, which play a good role in resisting the bending and torsional deformation of the overall structure.

[0034] Analysis and calculations show that, under the premise that the external load borne by the reactor remains unchanged, the overall structure fully demonstrates its mutual support characteristics, the bearing capacity is significantly enhanced, and the strength and stability of the structure can pass the verification smoothly, thus achieving a leapfrog technical effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a structural schematic diagram of a series tube reactor in the prior art.

[0036] Figure 2 It is a schematic structural diagram of a spirally arranged tube-in-tube reactor in an embodiment.

[0037] Figure 3 Schematic diagram of one of the spiral pipe layout methods in the embodiment.

[0038] Figure 4 Schematic diagram of the second spiral pipe arrangement method in the embodiment.

[0039] Figure 5 Schematic diagram of the third spiral pipe arrangement method in the embodiment.

[0040] Figure 6 It is a schematic diagram of the connection between the supports of two straight casings through a lining plate in the embodiment.

[0041] Figure 7 It is a schematic diagram of a row of straight sleeves in an embodiment being connected by a same connecting beam.

[0042] Figure 8 It is a schematic diagram of connecting the straight sleeves in the same row through the inter-tube connector in the embodiment.

[0043] Fig. 9 Schematic diagram of the horizontal beam and the diagonal bracing beam between three adjacent straight sleeves in the embodiment. DETAILED DESCRIPTION

[0044] The following will be combined with the accompanying drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0045] A spiral pipe series reactor of this embodiment, such as Figure 2As shown, it includes six straight sleeves R1, R2, R3, R4, R5, R6 and multiple elbows. The reaction materials enter the series tube reactor from the reaction material inlet 1A and are discharged from the reaction material outlet 1B. Each straight sleeve includes an inner tube and an outer tube. The inner tube is inserted into the outer tube to form an annular straight jacket flow channel. The inner tubes of multiple straight sleeves are connected in series through elbows to form a medium flow channel for transporting and reacting the reaction materials, and the straight jacket flow channels of multiple straight sleeves are connected in series to form a cooling flow channel for transporting cooling medium.

[0046] The series tube reactor also includes multiple jacket connecting pipes; the straight jacket flow channels of multiple straight tubes are connected in series as follows: the curved pipe is a single-layer pipe, and the two ends of the jacket connecting pipe are connected to the outer tube side walls of different straight tubes and connected to the corresponding straight jacket flow channels, so that the straight jacket flow channels of two adjacent straight tubes are directly connected through the jacket connecting pipe. This series connection structure is a traditional series connection method. Later, the inventor designed the elbow to be a double-layer jacket structure, that is, each elbow is a double-layer tube including an outer elbow and an inner elbow, and the outer elbow is sleeved on the outer side of the inner elbow to form an annular elbow jacket flow channel; the inner tubes of different straight sleeves are connected in series via the inner elbow to form the medium flow channel; the two ends of the straight jacket flow channel and the curved jacket flow channel are respectively provided with sealing structures, so as to seal the two ports of the straight jacket flow channel and the two ports of the curved jacket flow channel; one end of the jacket connecting pipe is connected to the outer tube side wall of the straight sleeve and connected to the straight jacket flow channel, and the other end of the jacket connecting pipe is connected to the outer elbow side wall of the elbow and connected to the curved jacket flow channel, so that the straight jacket flow channels of two adjacent straight sleeves are connected via the jacket connecting pipe and the curved jacket flow channel. The structures of the elbows and jacket connecting pipes disclosed in the Chinese patent documents with publication numbers CN219984696U, CN219984695U, and CN219984692U can be referred to, and will not be elaborated here.

[0047] The above is the basic structure of the existing series of pipe reactors. The series of pipe reactors in this embodiment also has these basic structures, and the following improvements are made:

[0048] A plurality of straight sleeves are arranged in two or more rows, and the two ends of each curved pipe are connected to the ends of straight sleeves in different rows, so that the plurality of straight sleeves and the plurality of curved sleeves are arranged in a spiral shape. The spacing between R1 and R3, R3 and R5 is the pitch, and the spacing between R2 and R4, R4 and R6 is also the pitch; the spacing between R1 and R2, R3 and R4, R5 and R6 is equal to the bending diameter of the curved pipe, and the spacing between R2 and R3, R4 and R5 is also equal to the bending diameter of the curved pipe.

[0049] Depend on Figure 2 As shown by the arrow at the top, the flow direction of the medium in the three elbows is consistent, and the flow direction of the medium in the two elbows at the bottom is also consistent. The advantages are strong regularity, easy identification and management, and small footprint.

[0050] One of the spiral pipe layout methods is reference Figure 3 As shown, two rows of straight sleeves are arranged one by one, and straight sleeves R1 to R6 are connected in series in sequence. Figure 4 As shown, two rows of straight casing are staggered and the pitch is a single value. Figure 5 As shown, the pitch of the spiral pipe arrangement is a variable value.

[0051] When installing the serial pipe reactor at the site of use, the seasonal wind direction of the use environment is first determined, that is, the wind direction with strong winds for a long time is the windward direction, and the spiral direction of the spiral pipe arrangement is the preset windward direction. The front straight sleeve plays a shielding role for the rear straight sleeve, reducing the effect of wind load on the rear straight sleeve structure, improving equipment reliability and extending equipment life.

[0052] In this embodiment, along the pitch direction of the spiral pipe arrangement, the distance between the centers of the two adjacent straight sleeves is H, the outer diameter of the straight sleeve is L, H / L≤4.5, and the wind load on a considerable part of the structure is reduced. The outer side of the straight sleeve is wrapped with an insulation layer, and L is the outer diameter of the insulation layer.

[0053] See also Figure 6 In the embodiment shown, a support 1 is provided in the middle of each straight sleeve. Figure 6 Taking the straight bushings R2 and R4 as an example, the straight bushings in the same row are arranged close to each other, and the supports 1 of two adjacent straight bushings are closely abutted or almost closely attached, and a lining plate 2 is provided between them to connect them.

[0054] refer to Figure 7 In the embodiment shown, the supports of the same row of straight sleeves are connected to the same connecting beam 3, so the structure is simplified.

[0055] Or refer to Figure 8 In the embodiment shown, the supports in the pitch direction of the two straight casings and the same connecting beam are eliminated and replaced by intermittently arranged pipe connecting members 6, thereby simplifying the structure to the maximum extent. The pitch is further reduced, and the occupied area is minimized.

[0056] refer to Fig. 9 In the embodiment shown, a horizontal beam 4 arranged horizontally and a diagonal bracing beam 5 arranged obliquely are provided between every three adjacent straight sleeves, and the horizontal beam 4 and the diagonal bracing beam 5 are in a triangular shape in the longitudinal projection.

[0057] In the description of the present invention, it is obvious that the described embodiments are only some embodiments of the present invention, rather than all embodiments. The components of the embodiments of the present invention generally described and shown in the drawings herein can be arranged and designed in various different configurations.

[0058] Therefore, the above detailed description of the embodiments of the utility model provided in the accompanying drawings is not intended to limit the scope of the utility model claimed for protection, but merely represents selected embodiments of the utility model. Based on the embodiments of the utility model, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of the utility model.

[0059] In the description of the present utility model, it should be noted that the terms "middle", "upper", "lower", "horizontal", "inner", "outer", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the invented product is usually placed when in use, which are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0060] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be directly connected or indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Claims

1. A spirally arranged tube-in-tube reactor, comprising a plurality of straight tubes and a plurality of curved tubes, each straight tube comprising an inner tube and an outer tube, the inner tube being inserted into the outer tube to form an annular straight jacket flow channel; the inner tubes of the plurality of straight tubes are connected in series via curved tubes to form a medium flow channel for transporting reaction materials and reacting, and the straight jacket flow channels of the plurality of straight tubes are connected in series to form a cooling flow channel for transporting cooling medium, and sealing structures are provided at both ends of the straight jacket flow channel to seal the two ends of the straight jacket flow channel; the characteristics are: A plurality of straight sleeves are arranged in two or more rows, and both ends of each curved pipe are respectively connected to ends of straight sleeves in different rows, so that the plurality of straight sleeves and the plurality of curved sleeves are arranged in a spiral shape.

2. The spirally arranged tube-in-tube reactor according to claim 1, characterized in that: The series pipe reactor also includes a plurality of jacketed connecting pipes; The straight jacket flow passages of multiple straight sleeves are connected in series as follows: the elbow is a single-layer pipe, and the two ends of the jacket connecting pipe are connected to the outer pipe side walls of different straight sleeves and connected to the corresponding straight jacket flow passages, so that the straight jacket flow passages of two adjacent straight sleeves are directly connected through the jacket connecting pipe; Alternatively, each curved pipe is a double-layer pipe including an outer elbow and an inner elbow, the outer elbow is sleeved on the outer side of the inner elbow to form an annular curved jacket flow channel; the inner pipes of different straight sleeves are connected in series via the inner elbow to form the medium flow channel; the two ends of the curved jacket flow channel are respectively provided with sealing structures to seal the two ends of the curved jacket flow channel; one end of the jacket connecting pipe is connected to the outer pipe side wall of the straight sleeve and connected to the straight jacket flow channel, and the other end of the jacket connecting pipe is connected to the outer elbow side wall of the curved pipe and connected to the curved jacket flow channel, so that the straight jacket flow channels of two adjacent straight sleeves are connected via the jacket connecting pipe and the curved jacket flow channel.

3. The spirally arranged tube-in-tube reactor according to claim 1, characterized in that: The spiral direction of the spiral pipe arrangement is a preset windward direction.

4. The spirally arranged tube-in-tube reactor according to claim 1, characterized in that: Along the pitch direction of the spiral pipe arrangement, the distance between the centers of two adjacent straight sleeves is H, the outer diameter of the straight sleeve is L, and H / L≤4.

5.

5. The spirally arranged tube-in-tube reactor according to claim 4, characterized in that: The outer side of the straight sleeve is wrapped with a heat-insulating layer, and L is the outer diameter of the heat-insulating layer.

6. The spirally arranged tube-in-tube reactor according to claim 1, characterized in that: A support is respectively arranged in the middle of each straight sleeve, and the supports of the straight sleeves in the same row are connected to the same connecting beam.

7. The spirally arranged tube-in-tube reactor according to claim 1, characterized in that: The straight sleeves in the same row are arranged close to each other, and lining plates are provided between the supports of two adjacent straight sleeves for connection.

8. The spirally arranged tube-in-tube reactor according to claim 1, characterized in that: A horizontal beam arranged horizontally and a diagonal bracing beam arranged obliquely are arranged between every three adjacent straight sleeves, and the horizontal beam and the diagonal bracing beam are in a triangular shape in the longitudinal projection.

9. The spirally arranged tube-in-tube reactor according to claim 1, characterized in that: The straight casings in different rows are arranged in alignment or staggered.

10. The spirally arranged tube-in-tube reactor according to claim 1, characterized in that: The pitch of the spiral pipe arrangement is a single value or a variable value.

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