Method of assembling a petrochemical plant

Abstract

The present application relates to the technical field of petrochemical device manufacturing, and particularly relates to a kind of closed petrochemical device's assembly welding method, the flange of the connection is separated out for pre-use in the process of assembly welding connection cylinder section, the connection cylinder section can be entered into the installation position between first cylinder section and second cylinder section at one time, then the end of connection cylinder section or the straight pipe section of flange is marked and cut, that is, the corresponding connection cylinder section and flange are placed to carry out assembly welding.Relative to hoist and lift the whole connection cylinder section many times, the volume of flange is smaller, and the weight is lighter, even if it needs to be moved many times, it is relatively more labor-saving, and the assembly precision is better controlled.The above new method greatly reduces the hoisting and cutting times during assembly, thereby improving the production efficiency of petrochemical device, reducing the labor cost and the occupancy rate of crane resources;Moreover, the cut of the final joint can be formed at one time, so the gap of subsequent assembly is uniform, which greatly improves the quality of assembly welding.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of petrochemical device manufacturing, and particularly relates to a closed petrochemical device assembling and welding method. BACKGROUND

[0002] The petrochemical device generally comprises multiple cylinder segments, which are connected to each other by welding. For different process requirements, the multiple cylinder segments in the petrochemical device are arranged in different ways. In the manufacturing of the petrochemical device, corresponding process schemes are respectively formulated according to the structural characteristics and related manufacturing precision requirements of each part, and the manufacturing is performed through computer accurate lofting and physical model lofting, special tooling and special machining equipment. The manufacturing precision and quality of each component are ensured by using assembly model, platform vertical projection and high-precision measuring instruments. After the completion of the component manufacturing, the whole precision assembly of each part is performed by using special platform and assembly mold, so as to ensure the connection and sealing of each component and the related shape, size and installation size requirements.

[0003] Different from the ordinary small and medium-sized cylinder welding, the petrochemical device has a large diameter and is like a high-rise building as a whole, and the different segments of the petrochemical device need to be precisely docked during assembly. Taking three cylinder segments of the petrochemical device as an example, the target is to obtain a module in which the first cylinder segment, the connecting cylinder segment and the second cylinder segment are sequentially connected and welded. In actual manufacturing, the first cylinder segment and the second cylinder segment are horizontally placed and fixed by tooling, the connecting cylinder segment is hoisted to make both ends thereof assembled and the first cylinder segment and the second cylinder segment are welded. The opening of the first cylinder segment is provided with a first flange, the opening of the second cylinder segment is provided with a second flange, and the pipe connecting flanges at both ends of the connecting cylinder segment are previously fixed with the first flange and the second flange, so that both ends of the connecting cylinder segment are straight pipe bodies without flanges, and the assembling and welding target is the straight sections of the two connecting flanges at both ends of the connecting cylinder segment.

[0004] Specifically, the assembling and welding process is as follows: the connecting flanges and the connecting cylinder segment are separated, and the two connecting flanges are respectively installed to the flanges of the first cylinder segment and the second cylinder segment. The first cylinder segment and the second cylinder segment are previously positioned by tooling. Since the hoisted connecting cylinder segment needs to be adjusted during assembly, a margin is left at both ends of the connecting cylinder segment. The connecting cylinder segment is hoisted to be close to the first cylinder segment and the second cylinder segment, the distance and angle are adjusted, and then the both ends of the connecting cylinder segment are respectively marked and cut. Then, the both ends of the connecting cylinder segment are cut multiple times for correction until the size of the end of the connecting cylinder segment after cutting and the assembly gap between the connecting flanges meet the requirements, and then welding is performed.

[0005] The above group welding method has the following problems: As can be seen from the above, because the end of the adapter cylinder section is left with a cutting allowance, it is necessarily longer than the theoretical size in the drawing. Therefore, when the frame is placed according to the theoretical size in the drawing, and the flanges of the adapter cylinder section are installed on the second cylinder section and the first cylinder section, they will block the adapter cylinder section when hoisted for the first time, and further cause the cutting line when closing the joint to be inaccurate, and finally cause the need for multiple hoisting, and the size of the adapter cylinder section is gradually marked, cut and modified until it meets the group welding requirements. The process is very cumbersome, and a lot of manpower and time is consumed. SUMMARY

[0006] In view of the above technical problems existing in the prior art, the present application provides a group welding method for a closed petrochemical device.

[0007] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0008] The present application provides a group welding method for a closed petrochemical device, the petrochemical device comprising a first cylinder section, an adapter cylinder section and a second cylinder section which are coaxially and sequentially communicated, the first cylinder section and one end of the adapter cylinder section, and the second cylinder section and the other end of the adapter cylinder section are respectively connected and fixed by flanges which are group welded with each other; characterized in that the group welding method for the above petrochemical device comprises the following steps:

[0009] The pre-preparation step: the first flange is fixed at the opening of the first cylinder section, the second flange is fixed at the opening of the second cylinder section, and the adapter flange with a straight pipe section corresponding to the end of the adapter cylinder section is separated for pre-use; the end of the adapter cylinder section and / or the straight pipe section of the adapter flange is left with a preset cutting length allowance X;

[0010] The positioning step: the first cylinder section and the second cylinder section are horizontally fixed by a tool according to a preset relative position; in the overall axial direction, the distance between the first flange and the second flange is S, the distance between the two ports of the adapter cylinder section is L, and the length of the adapter flange is M, S>L, L+M-X=S;

[0011] The hoisting step: the adapter cylinder section is hoisted between the ports of the first flange and the second flange, the orientation of the adapter cylinder section is adjusted according to the preset size, and then the adapter cylinder section is fixed by a tool, the orientation including the angle and the distance between the two ends of the adapter cylinder section relative to the ports of the first cylinder section and the second cylinder section;

[0012] The cutting step: according to the port distance and the length of the adapter cylinder section and / or the straight pipe section of the adapter flange, the end of the adapter cylinder section and / or the straight pipe section of the adapter flange is accurately marked and cut;

[0013] The group welding step: the adapter flange is placed into and welded with the end of the adapter cylinder section, forming a pipe section structure in which the first cylinder section, the adapter cylinder section and the second cylinder section are sequentially and tightly communicated.

[0014] Specifically, the center lines of the first cylinder section, the connecting cylinder section and the second cylinder section are in the same plane.

[0015] Specifically, the center lines of the first cylinder section, the connecting cylinder section and the second cylinder section are in different planes.

[0016] Specifically, in the hoisting step, the connecting cylinder section is hoisted by using a sling, and the connecting cylinder section is provided with a hoisting part for fixing the sling.

[0017] Specifically, the connecting cylinder section is a straight pipe or an elbow pipe.

[0018] Specifically, the openings of the first cylinder section and the second cylinder section are located at the end portions or the side portions.

[0019] The beneficial effects of the present application are as follows:

[0020] The present application is a method for assembling and welding a closed petrochemical device, which is directed to a first cylinder section, a connecting cylinder section and a second cylinder section. The inventor has found that the main problem of the old assembly scheme is that the folding seam cutting line cannot be accurately drawn, and the main factor affecting the accuracy of the cutting line is the first flange, the connecting flange and the second flange. These factors will affect the cutting line of the folding seam after installation.

[0021] Therefore, the present application breaks the hindering factors in the old scheme. In the process of assembling and welding the connecting cylinder section, the connecting flange with a straight pipe section is separated out for pre-use. In this way, there is enough length of installation position between the first cylinder section and the second cylinder section, and the connecting cylinder section can be placed in the installation position at one time. Then, the straight pipe section of the connecting flange at the end portion of the connecting cylinder section is drawn and cut, and the corresponding connecting flange is placed for assembly and welding. Compared with hoisting the whole connecting cylinder section back and forth multiple times, the volume of the connecting flange is smaller and the weight is lighter, so even if multiple movements are needed, it is relatively more labor-saving and better to control the assembly accuracy.

[0022] The above new method greatly reduces the hoisting and cutting times during assembly, thereby improving the production efficiency of the petrochemical device, reducing the labor cost and the occupancy rate of the crane resources; and the final folding seam cut can be formed by one cutting, so that the gap of the subsequent assembly is uniform, greatly improving the quality of the assembly and welding. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a schematic diagram of the first cylinder section, the connecting cylinder section and the second cylinder section in the embodiment.

[0024] Figure 2 It is a schematic diagram of the first cylinder section and the connecting cylinder section before assembly and welding in the embodiment.

[0025] REFERENCE NUMERALS:

[0026] The first cylinder section 1, the first flange 11, the second cylinder section 2, the second flange 21, the connecting cylinder section 3 and the connecting flange 31. DETAILED DESCRIPTION

[0027] The present application is described in detail below with reference to specific embodiments and drawings.

[0028] A method for assembling a closed petrochemical device is provided, as shown in Figure 1 and Figure 2 The petrochemical device includes a first cylinder segment 1, a connecting cylinder segment 3, and a second cylinder segment 2 arranged coaxially and sequentially connected. In use, the first cylinder segment 1 and the second cylinder segment 2 are arranged longitudinally, and the opening of the first cylinder segment 1 and one end of the connecting cylinder segment 3, and the opening of the second cylinder segment 2 and the other end of the connecting cylinder segment 3 are respectively connected and fixed by flanges assembled with each other. The method for assembling the petrochemical device includes the following steps:

[0029] A prefabrication step: a first flange 11 is fixed at the opening of the first cylinder segment 1, a second flange 21 is fixed at the opening of the second cylinder segment 2, and a connecting flange 31 with a straight pipe segment corresponding to the end of the connecting cylinder segment 3 is separated for pre-use; the end of the connecting cylinder segment 3 and / or the straight pipe segment of the connecting flange 31 is left with a preset cutting length allowance X;

[0030] A positioning step: the first cylinder segment 1 and the second cylinder segment 2 are fixed horizontally at a preset relative position by a tool; in the overall axial direction, the distance between the first flange 11 and the second flange 21 is S, the distance between the two ports of the connecting cylinder segment 3 is L, and the length of the connecting flange 31 is M, S>L, L+M-X=S; the purpose is that the prefabricated connecting cylinder segment 3 can be placed between the first cylinder segment 1 and the second cylinder segment 2 at one time, and the three cylinder segments after cutting can be accurately connected.

[0031] A hoisting step: the connecting cylinder segment 3 is hoisted to the port between the first flange 11 and the second flange 21, the orientation of the connecting cylinder segment 3 is adjusted according to the preset size, and then the connecting cylinder segment 3 is fixed by a tool, the orientation including the angle and the distance between the two ends of the connecting cylinder segment 3 relative to the ports of the first cylinder segment 1 and the second cylinder segment 2;

[0032] A cutting step: according to the port distance h and the length of the connecting cylinder segment 3 and / or the straight pipe segment of the connecting flange 31, the end of the connecting cylinder segment 3 and / or the straight pipe segment of the connecting flange 31 is accurately marked and cut; for example, the cutting line c of the connecting cylinder segment 3 and the cutting line d of the straight pipe segment of the connecting flange 31 are determined according to the measurement data.

[0033] An assembly step: the connecting flange 31 is placed in and welded with the end of the connecting cylinder segment 3, forming a pipe segment structure in which the first cylinder segment 1, the connecting cylinder segment 3, and the second cylinder segment 2 are sequentially and tightly connected.

[0034] Specifically, the center lines of the first cylinder segment 1, the connecting cylinder segment 3 and the second cylinder segment 2 are in the same plane. In practice, the center lines of the first cylinder segment 1, the connecting cylinder segment 3 and the second cylinder segment 2 can be in different planes according to requirements.

[0035] Specifically, in the lifting step, the connecting cylinder segment 3 is lifted by using a sling, and the connecting cylinder segment 3 is provided with a lifting position for fixing the sling.

[0036] Specifically, the connecting cylinder segment is an arc-shaped elbow pipe. In practice, the connecting cylinder segment can be a straight pipe or an elbow pipe with more than 180 degrees according to requirements.

[0037] Specifically, the openings of the first cylinder segment 1 and the second cylinder segment 2 are located at the end portions or the side portions.

[0038] The embodiment breaks the hindering factors in the old scheme, and the connecting flange 31 with a straight pipe segment is separated out for pre-use in the process of assembling and welding the connecting cylinder segment 3. In this way, a sufficient length of installation position is left between the first cylinder segment 1 and the second cylinder segment 2, and the connecting cylinder segment 3 can be placed in the installation position at one time. Then, the straight pipe segment of the connecting flange 31 and / or the end portion of the connecting cylinder segment 3 is cut by using a line, and the connecting flange 31 is assembled and welded. Relatively, the whole connecting cylinder segment 3 is lifted back and forth for multiple times, the volume of the connecting flange 31 is smaller, the weight is lighter, and even if the connecting flange 31 needs to be moved multiple times, it is relatively more labor-saving, and the assembly and welding precision can be better controlled.

[0039] The above new method greatly reduces the lifting and cutting times during assembly and welding, thereby improving the production efficiency of the petrochemical device, reducing the labor cost and the occupancy rate of the crane resources. Moreover, the cut of the final closing seam can be formed by one-time cutting, so that the gap of the subsequent assembly and welding is uniform, and the assembly and welding quality is greatly improved.

[0040] In the description of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting", "fixing" should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrated; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the communication inside two elements or the interaction relationship between two elements. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0041] The standard parts used in the present application can be purchased from the market, and the special-shaped parts can be ordered according to the description and the drawings. The specific connection mode of each part adopts the conventional means such as bolts, rivets and welding in the prior art. The machinery, parts and equipment adopt conventional models in the prior art, and the circuit connection adopts the conventional connection mode in the prior art, which will not be described in detail here.

[0042] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and adaptions can be effected without departing from the spirit and scope of the application, as set forth in the claims appended hereto.

[0043] Finally, it should be noted that the above-mentioned embodiments are merely used to illustrate the technical solutions of the present application, but not limit the protection scope of the present application. Although the present application is described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalent replaced without departing from the spirit and scope of the present application.

Claims

1. A method for assembling and welding a closed petrochemical unit, the petrochemical unit comprising a first cylindrical section, a connecting cylindrical section, and a second cylindrical section coaxially connected in sequence, wherein one end of the first cylindrical section and the connecting cylindrical section, and the other end of the second cylindrical section and the connecting cylindrical section, are respectively connected and fixed by flanges welded together; characterized in that, The assembly and welding method for the above petrochemical units includes the following steps: Prefabrication steps: Fix the first flange at the opening of the first cylinder section, fix the second flange at the opening of the second cylinder section, and separate the connecting flange with the straight pipe section corresponding to the end of the connecting cylinder section for pre-use; leave a preset cutting length allowance X at the end of the connecting cylinder section and / or the straight pipe section of the connecting flange. Positioning steps: The first and second cylinder sections are horizontally fixed in a preset relative position using tooling; in the overall axial direction, the distance between the first and second flanges is S, the distance between the two ends of the connecting cylinder section is L, the length of the connecting flange is M, S>L, L+MX=S; Lifting steps: Lift the connecting cylinder section between the ports of the first flange and the second flange, adjust the orientation of the connecting cylinder section according to the preset dimensions, and then fix the connecting cylinder section with tooling. The orientation includes the angle and the distance between the two ends of the connecting cylinder section relative to the ports of the first cylinder section and the second cylinder section. Cutting steps: Based on the port distance and the length of the straight pipe section of the connecting cylinder and / or connecting flange, accurately scribble and cut the straight pipe section at the end of the connecting cylinder and / or connecting flange; Assembly welding steps: Insert the connecting flange and weld it to the end of the connecting cylinder section to form a pipe section structure in which the first cylinder section, the connecting cylinder section, and the second cylinder section are sequentially sealed and connected.

2. The welding method for a closed petrochemical plant according to claim 1, characterized in that: The centerlines of the first section, the connecting section, and the second section are on the same plane.

3. The welding method for a closed petrochemical plant according to claim 1, characterized in that: The centerlines of the first section, the connecting section, and the second section are on different planes.

4. The welding method for a closed petrochemical plant according to claim 1, characterized in that: In the hoisting process, slings are used to hoist the connecting cylinder section, and the connecting cylinder section is provided with a hoisting part for fixing the slings.

5. The welding method for a closed petrochemical plant according to claim 1, characterized in that: The connecting cylindrical section can be a straight pipe or a bend.

6. The assembly and welding method for a closed petrochemical unit according to claim 1, characterized in that: The openings of the first and second sections are located at the ends or on the sides.

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