A method for positioning a loop reactor by means of an assembly stand

Abstract

The invention discloses an annular tube reactor with a height-adjustable support, comprising a plurality of straight sleeves, a plurality of jacketed connecting pipes, a plurality of elbows, a plurality of support ring seats and an axial flow pump, wherein each straight sleeve comprises an inner tube and an outer tube, the outer tube is sleeved outside the inner tube, and a plurality of elbows connect the plurality of inner tubes and the axial flow pump in series in sequence, thereby forming a connecting flow channel for conveying reaction materials, and the axial flow pump is located at the elbow connected to the lower end of the straight sleeve; the jacketed connecting pipe is located at the elbow and connected to the outer tube, thereby connecting the space between the inner tube and the outer tube in series to form another connecting flow channel for conveying cooling medium; in practice, suppliers of components such as straight sleeves and elbows can reserve a position for assembling the axial flow pump in advance according to the positioning of the assembly frame, and at the assembly site, assemblers can quickly and timely perform centering connection between the axial flow pump and the elbow according to the relative positions of the base of the assembly frame and the support block, and the axial flow pump is supported, which is more convenient for installation.

Description

Technical Field

[0001] The invention relates to the technical field of special mechanical equipment for petrochemical industry, and in particular to a method for positioning a loop tube reactor through an assembly rack. Background Art

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

[0003] Loop reactor Figure 1 As shown, it is composed of several straight sleeves, jacket connecting pipes (C1-C5), elbows, support ring seats and connecting beams, among which every two straight tube cylinders and two connecting elbows form a loop. It is mainly composed of six straight sleeves (R1, R2, ... R6), five 180° large elbows (A1, A2, A3, B1, B2), and a 90° elbow B3 connected in sequence to form a circulation whole. The main body is located on a higher platform foundation, and the axial flow pump is located on the ground foundation. An axial flow pump is provided at the elbow at the bottom of the annular tube. The reaction material enters the annular tube reactor from 1A, and is stirred and circulated in the tube under the drive of the axial flow pump. Under the action of the catalyst, the reaction forms slurry polypropylene, which is discharged from 1B into the granulation system; the jackets are connected to each other by five jacket connecting pipes, and 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.

[0004] Because the polymerization reaction will generate heat, the reaction heat is taken away through the cold water in the jacket. The outer tube of the straight sleeve is provided with a corrugated expansion joint, a support ring seat (D1-D6) and a support beam seat. There is no sleeve on the elbow. The elbow is connected to the two ends of the inner tube of the straight sleeve through a flange to connect the straight sleeve into a whole process. The jacket connecting pipe connects the jacket of the straight sleeve into a whole process. The connecting beam is connected to the support beam seat by bolts to combine the straight sleeve into a three-dimensional frame. The annular tube reactor is supported by multiple foundations, that is, each straight sleeve has its own support ring seat. 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 connecting elbow, and many other factors will affect the sealing performance of the annular tube installation at the same time.

[0005] Olefins are flammable and explosive media, and the sealing performance of the annular tube reactor is the key to the stable, long-term full-load operation of the device. The axial flow pump is supplied by a separate manufacturer, and the other parts except the axial flow pump are supplied by another manufacturer. This leads to the need to reserve assembly positions for the axial flow pump in advance when manufacturing components such as straight sleeves and elbows, which is a traditional design and manufacturing technical requirement for annular tube reactors at home and abroad. In the manufacturing stage of the annular tube reactor, the straight sleeve and its support ring seat are first welded. During the upright installation stage of the annular tube reactor, each straight sleeve is supported by its own pre-welded support ring seat on the reinforced concrete structure of the high-altitude platform, and then the positioning dimensions of the ground foundation axial flow pump are measured and adjusted. Due to the lack of support and positioning of the axial flow pump, the following problems will exist in practice:

[0006] The closed structure is difficult to install. In order to meet the huge market demand and development for ethylene special materials, the production capacity of the annular tube reactor equipment has been gradually increased from 70,000 tons / year in the 1990s to 400,000 tons / year, and is aimed at more than 500,000 tons / year. In large annular tube reactors, the spatial elevation difference between the straight sleeve installation reference plane and the axial flow pump installation reference plane is widened. In the limited space before and after the axial flow pump, the main body straight section, elbows and a series of auxiliary inspection port pipelines are densely installed. The matching accuracy between the various parts is required to be high. Large axial flow pumps are difficult to fine-tune. The traditional interface structure does not have the assembly flexibility between the various parts, and cannot guarantee the demanding assembly accuracy between the axial flow pump outlet and the reactor inlet. Therefore, the closed installation of the annular tube reactor equipment has to leave a section of the connecting elbow and its flexible flange to be welded on site, and the elbow port, axial flow pump outlet and reactor inlet are connected by cutting and grinding.

[0007] According to relevant regulations, the welding between the elbow and the straight sleeve falls within the scope of supply of the equipment supplier. During the assembly stage, the equipment supplier needs to send a construction team to the site for welding and to perform heat treatment and pressure resistance tests on the welds. In addition, the market supervision department at the supplier's location needs to send personnel to the construction site to supervise, inspect, and accept the entire process, sign certification documents, and form a complete set of filing materials together with the product manufacturing process files originally in the equipment supplier's manufacturing workshop. This increases the difficulties and costs of the equipment supplier, and this contradiction is more prominent in long-distance overseas projects.

[0008] In summary, in order to quickly adapt to the current market environment of large demand for high-capacity and large-structured loop tube reactors in the new construction and expansion of petrochemical industry, meet the needs of capacity increase, expansion and upgrading of traditional loop tube reactors, and high-capacity demand of polypropylene production capacity of more than 400,000 tons / year, the development of new-structure high-capacity loop tube reactors and their overall supply and installation technology has far-reaching and significant industrial and economic significance. Summary of the invention

[0009] In view of the above technical problems in the prior art, the present invention provides a method for positioning a loop tube reactor through an assembly stand, which is convenient for installing an axial flow pump.

[0010] To achieve the above object, the present invention provides the following technical solutions:

[0011] Provided is a method for positioning an annular tube reactor through an assembly rack, comprising a plurality of straight sleeves, a plurality of jacketed connecting pipes, a plurality of elbows, a plurality of support ring seats and an axial flow pump, wherein each straight sleeve comprises an inner tube and an outer tube, the outer tube is sleeved outside the inner tube, a plurality of elbows connect the plurality of inner tubes and the axial flow pump in series in sequence, thereby forming a connecting flow channel for conveying reaction materials, the axial flow pump is located at the elbow connected to the lower end of the straight sleeve; the jacketed connecting pipe is located at the elbow and connected to the outer tube, thereby connecting the space between the inner tube and the outer tube in series to form another connecting flow channel for conveying cooling medium; a plurality of support ring seats are respectively fixed to the outer sides of the plurality of outer tubes; an assembly rack is provided at the bottom of the annular tube reactor, the assembly rack comprises a base, a pillar and a support block, the base is used to hold the axial flow pump, the pillar stands on the base, the support block is fixed to the upper end of the pillar to support the corresponding support ring seat, thereby positioning the relative position of the axial flow pump and the support ring seat.

[0012] Preferably, the number of the pillars is more than two, and the support block at the upper end of each pillar supports a different support ring seat.

[0013] Preferably, a reinforcement member is provided between two adjacent pillars.

[0014] Preferably, the base is provided with lifting ears.

[0015] Preferably, the assembly frame is a cast steel structure or a welded structure as a whole.

[0016] Preferably, a first concrete platform for installing the support ring seat is arranged outside the straight sleeve, a second concrete platform is arranged below the straight sleeve, and the base is installed on the second concrete platform.

[0017] Preferably, there are two sets of assembly frames, and one set is selected to locate the relative position of the axial flow pump and the support ring seat.

[0018] Preferably, the base is provided with an adjusting member, which is connected to the base to adjust the top surface of the base to be horizontal.

[0019] Preferably, the base is provided with an elastic pad which presses upward against the elbow or the axial flow pump.

[0020] Preferably, the base is provided with a stud hole, and the axial flow pump is provided with a mounting hole aligned with the stud hole.

[0021] Beneficial effects of the present invention:

[0022] Compared with the prior art, the method of positioning the annular tube reactor by means of an assembly stand of the present invention positions the relative positions of the axial flow pump and the support ring seat by means of an assembly stand. Therefore, in practice, suppliers of components such as straight sleeves and connecting elbows can reserve positions for assembling the axial flow pump in advance according to the positioning of the assembly stand. At the assembly site, assemblers can quickly and timely center the axial flow pump and the connecting elbow according to the relative positions of the base of the assembly stand and the support block, and the axial flow pump can be supported, making installation more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of a loop reactor in the prior art.

[0024] Figure 2 Schematic diagram of the structural relationship between the assembly frame and the loop reactor in the embodiment.

[0025] Figure 3 It is a structural schematic diagram of one of the assembly racks in the embodiment.

[0026] Figure 4 It is a structural schematic diagram of another assembly rack in the embodiment.

[0027] Figure 5 Schematic diagram of the structure of the support block in the embodiment.

[0028] Reference numerals:

[0029] exist Figure 1 Included are:

[0030] R1, R2, R3, R4, R5, R6 - straight casing;

[0031] A1, A2, A3, B1, B2, B3 - elbows;

[0032] C1, C2, C3, C4, C5——jacket connecting pipes;

[0033] D1, D2, D3, D4, D5, D6——support ring seat;

[0034] 2A——cooling medium inlet of jacket flow channel, 2F——cooling medium outlet of jacket flow channel;

[0035] 1A——reaction material inlet, 1B——reaction material outlet.

[0036] exist Figures 2 to 5 Included are:

[0037] R1, R2, R3, R4, R5, R6 - straight casing, R11 - straight casing outlet extension section,

[0038] A1, A2, A3, B1, B2, B3——elbow,

[0039] d1, d2, d3, d4, d5, d6——support ring seat,

[0040] a——reactor feed port, b——reactor discharge port,

[0041] g——axial flow pump,

[0042] w1——the connecting elbow between the axial flow pump and the reactor outlet,

[0043] w2——the connecting elbow between the axial flow pump and the reactor reflux port,

[0044] E1 – the second concrete platform, E2 – the first concrete platform.

[0045] T——assembly frame, T1——base, T2——adjustment part, T3——pillar, T4——support block, T5——reinforcement part, T6——lifting ear, T7——support block.

[0046] T41 – frame, T42 – reinforcement beam, T43 – stud hole. DETAILED DESCRIPTION

[0047] The present invention is described in detail below in conjunction with specific embodiments and drawings.

[0048] Example 1

[0049] One of the specific embodiments of the loop reactor with height-adjustable support of the present invention is as follows: Figure 2 and Figure 3 As shown, it includes a plurality of straight sleeves (R1, R2, R3, R4, R5, R6), a plurality of jacketed connecting pipes, a plurality of elbows (A1, A2, A3, B1, B2, B3), a plurality of branch ring seats (d1, d2, d3, d4, d5, d6) and an axial flow pump g, each straight sleeve includes an inner tube and an outer tube, the outer tube is sleeved outside the inner tube, a plurality of elbows connect the plurality of inner tubes and the axial flow pump g in series in sequence, thereby forming a connecting flow channel for conveying the reaction material, and the axial flow pump g is located between the elbows W1 and W2 connected to the lower ends of the straight sleeves R1 and R6. The jacketed connecting pipe is located at the elbow and connected to the outer tube, thereby connecting the space between the inner tube and the outer tube in series to form another connecting flow channel for conveying the cooling medium, wherein a is the inlet of the reaction material and b is the outlet of the reaction material. A plurality of branch ring seats are respectively fixed to the outer sides of the plurality of outer tubes. The above technical features are the same as the structure of the loop tube reactor in the prior art. As an improvement, the bottom of the loop tube reactor in this embodiment is provided with an assembly frame T as a height adjustment support. Figure 2As shown, the assembly frame T includes a base T1, a support T3 and a support block T4. The base T1 is used to hold the axial flow pump g. The support T3 stands on the base T1. The support block T4 is fixed to the upper end of the support T3 to support the corresponding support ring seat d1, thereby positioning the relative position of the axial flow pump g and the support ring seat d1. The structure of the support block T4 is shown in FIG. Figure 5 As shown, it includes a circular frame T41, a reinforcing beam T42 and a plurality of stud holes T43, the reinforcing beam T42 is cross-arranged on the frame T41, and the plurality of stud holes T43 are distributed circumferentially around the center of the frame T41.

[0050] In practice, suppliers of straight sleeves and connecting elbows and other components (except axial flow pumps, which are delivered to the installation site by a separate supplier) can reserve a position for assembling the axial flow pump g in advance according to the positioning of the assembly rack T, and the relative position between the reserved position and the support ring seat d1 of the straight sleeve R1 is determined. At the assembly site, the assemblers can quickly and timely align the axial flow pump g with the elbows w1 and w2 of the curved pipe according to the relative position of the base T1 of the assembly rack T and the support block T4, and support the axial flow pump g, making it more convenient to install.

[0051] The actual manufacturing process includes: first, according to the engineering technical requirements, the shape and position deviations of the outlet flange of the axial flow pump g, the flange of the inlet a and the elbow flange connecting the two flanges are clearly marked in the detailed construction drawing design of the annular tube reactor, and the shape and position deviations of each bolt hole on these multiple flanges are also clearly marked; second, two sets of assembly frames T are designed according to these shape and position deviations, the base T1 and the support block T4 are respectively provided with stud holes, the support ring seat d1 is provided with a mounting hole aligned with the stud hole T43 of the support block T4, and the axial flow pump g is provided with a mounting hole aligned with the stud hole on the base T1. All stud hole surfaces are veneered and drilled to ensure the orientation accuracy of the stud holes; third, the support block T4 is reinforced before drilling to make the structure firm, and the residual stress is eliminated to prevent it from deformation; fourth, there are two sets of assembly racks T, one of which is used at the supplier of straight casing to assemble other workpieces of the annular tube reactor except the axial flow pump g, simulating the reserved positioning position of the axial flow pump g; the other set of assembly racks is handed over to the civil engineering and installation units at the device site for positioning and installing the axial flow pump g.

[0052] A first concrete platform E2 for installing each support ring seat is arranged outside the straight sleeve, and a second concrete platform E1 is arranged below the straight sleeve, and the base T1 is installed on the second concrete platform E1. During assembly, the stud holes of the base T1 of the assembly frame T are inserted into the anchor bolts before pouring the second concrete platform E1 and pre-tightened with nuts, the stud holes of the support ring seat of the straight sleeve are aligned with the stud holes T43 of the support block T4 and inserted into the anchor bolts before pouring the first concrete platform E2 and pre-tightened with nuts, the mounting holes of the support block T4 are inserted, and then concrete is poured to form the second concrete platform E1, and then the base T1 is fixed to the second concrete platform E1. Then, the axial flow pump g is positioned and installed, and the anchor studs of the base T1 are installed through secondary pouring, and then the first concrete platform E2 is poured, and each support ring seat is fixed to the first concrete platform E2 through bolts combined with poured concrete. As can be seen from the above, the base T1 and the support block T4 are cast and fixed on the corresponding concrete platform, which are actually not removable and are integrated with the reactor in the later stage, while the support T3 can be cut off according to the actual situation, or concrete can be cast in the support T3 as a permanent structure to support the reactor. In practice, a protrusion or groove can be set on the top of the base T1 for pre-positioning when the axial flow pump g is placed at the beginning.

[0053] The loop reactor is precisely installed by means of an assembly frame T pre-buried in the second reinforced concrete E1. Figure 2 The support ring seat d1 on the straight sleeve R1 is installed on the support block T4 in the assembly frame block T. The axial flow pump g is installed on the base T1 in the assembly frame T. At the beginning of the installation, try to install the flanged elbows W1 and W2 first, and preliminarily determine the gap between the flanges at their ends and the flanges matched with the axial flow pump g; fine-tune the outlet orientation of the axial flow pump g according to the gap, leaving the axial displacement required for the outlet flange of the axial flow pump g and the elbow flange to be tightened; then tighten the flange of the elbow W1 and the lower end of the inner tube of the straight sleeve R1, as well as the flange of the elbow W2 and the flange of the lower end of the inner tube of the straight sleeve R6. According to the on-site conditions, if necessary, add an elastic pad under the axial flow pump g to press upward against the elbows W1, W2 or the axial flow pump g to reduce the vibration caused by the axial flow pump g during operation.

[0054] In this embodiment, the base T1 is provided with a lifting lug T6 to ensure balanced force during the lifting process and avoid deformation of the steel structure.

[0055] In this embodiment, the base T1 is provided with an adjusting member T2, which is connected to the base T1 to adjust the top surface of the base T1 to be horizontal, further ensuring the positioning accuracy of the axial flow pump g. The structure of the adjusting member T2 can be a pad or other forms.

[0056] In this embodiment, the assembly rack T is a cast steel structure or a welded structure as a whole. The steel structure of the assembly rack T is subjected to heat treatment or other processes to eliminate residual stress to prevent gradual deformation caused by gradual release of stress.

[0057] Example 2

[0058] The second specific embodiment of a loop reactor with a height-adjustable support of the present invention, the main technical scheme of this embodiment is the same as that of embodiment 1, and the features not explained in this embodiment are explained in embodiment 1, and will not be repeated here. The difference between this embodiment and embodiment 1 is that: Figure 4 As shown, there are two pillars T3, and the support block T4 at the upper end of each pillar T3 supports different support ring seats. The higher support block T7 directly positions the support ring seat d1 of the feed straight sleeve R1, and the lower support block T4 indirectly positions the support ring seat d6 of the straight sleeve R6 through the straight sleeve outlet extension section R11. A reinforcement member T5 is provided between two adjacent pillars T3. Of course, the number of pillars T3 can be changed to other numbers in practice, such as a one-to-one correspondence between pillars T3 and straight sleeves.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for positioning an annular tube reactor by an assembly rack, the annular tube reactor comprising a plurality of straight sleeves, a plurality of jacketed connecting pipes, a plurality of elbows, a plurality of branch ring seats and an axial flow pump, each straight sleeve comprising an inner tube and an outer tube, the outer tube being sleeved outside the inner tube, a plurality of elbows connecting the plurality of inner tubes and the axial flow pump in series in sequence, thereby forming a connecting flow channel for conveying reaction materials, the axial flow pump being located at the elbow connected to the lower end of the straight sleeve; the jacketed connecting pipe being located at the elbow and connected to the outer tube, thereby connecting the space between the inner tube and the outer tube in series to form another connecting flow channel for conveying cooling medium; a plurality of branch ring seats being fixed to the outer sides of the plurality of outer tubes respectively; the method comprising: The method comprises: First, according to the engineering technical requirements, the shape and position deviations of the outlet flange, inlet flange and elbow flange connecting the two flanges of the axial flow pump are clearly marked in the detailed construction drawing design of the loop reactor, and the shape and position deviations of the bolt holes on these multiple flanges are also clearly marked; Second, two sets of assembly frames are designed according to these shape and position deviations. The assembly frames include a base, a pillar and a support block. The base is used to hold the axial flow pump, the pillar stands on the base, and the support block is fixed to the upper end of the pillar to support the corresponding support ring seat, thereby positioning the relative position of the axial flow pump and the support ring seat; Third, there are two sets of assembly racks, one of which is used for assembling other workpieces of the annular tube reactor except the axial flow pump at the supplier of straight casing manufacturing, simulating the reserved axial flow pump positioning position; and at the assembly site, the assemblers can quickly and timely align the axial flow pump and the connecting elbow according to the relative position of the base and the support block of the assembly rack, and it also supports the axial flow pump. A first concrete platform for installing a support ring seat is provided on the outside of the straight casing, and a second concrete platform is provided below the straight casing, and the base is installed on the second concrete platform.

2. A method for positioning a loop reactor by an assembly stand according to claim 1, characterized in that: The number of the pillars is more than two, and the support block at the upper end of each pillar supports different support ring seats.

3. A method for positioning a loop reactor by an assembly stand according to claim 2, characterized in that: A reinforcement piece is arranged between two adjacent pillars.

4. A method for positioning a loop reactor by an assembly stand according to claim 1, characterized in that: The base is provided with hanging ears.

5. The method for positioning a loop reactor by an assembly stand according to claim 1, characterized in that: The assembly frame is a cast steel structure or a welded structure.

6. A method for positioning a loop reactor by an assembly stand according to claim 1, characterized in that: There are two sets of assembly brackets, and one set is selected to locate the relative position of the axial flow pump and the support ring seat.

7. The method for positioning a loop reactor by an assembly stand according to claim 1, characterized in that: The base is provided with an adjusting member, which is connected to the base so as to adjust the top surface of the base to be horizontal.

8. The method for positioning a loop reactor by an assembly stand according to claim 1, characterized in that: The base is provided with an elastic pad which presses upward against the elbow or the axial flow pump.

9. A method for positioning a loop reactor by an assembly stand according to claim 1, characterized in that: The base is provided with a stud hole, and the axial flow pump is provided with a mounting hole aligned with the stud hole.

Images