Horizontal fire tube waste heat boiler manufacturing optimization process

Abstract

This invention relates to the field of boiler manufacturing technology, and provides an optimized manufacturing process for a horizontal fire-tube waste heat boiler, including the following steps: Right side tube box manufacturing: S1, the diameter of the right side tube box is rolled according to the shell-side tube diameter + 2mm; S2, when welding accessories onto the right side tube box, the valve port connection is not welded; Left side tube box manufacturing: S3, a fitting hole is opened on the rear ring plate of the left side tube box, the diameter of the fitting hole being according to the shell-side tube diameter + 4mm; Shell-side tube box manufacturing: S4, the outer diameter deviation of the heat exchange tubes is measured to determine the deviation of the tube holes opened on the tube sheet; S5, the diameter of the center tube is measured, and the diameter of the center hole in the tube sheet is opened according to the center tube diameter + 2mm; Overall assembly: S6, the right side tube box and the left side tube box are sequentially fitted onto the shell-side tube; S7, the valve port connection is circumferentially fitted with the branch pipe of the heat-resistant tee pipe.

Description

Technical Field

[0001] This invention relates to the field of boiler manufacturing technology, specifically to an optimized manufacturing process for a horizontal fire-tube waste heat boiler. Background Technology

[0002] The fire-tube waste heat boiler uses medium-pressure steam generated during the cooling process of the process gas from waste acid cracking. This steam is then fed into a steam drum, separated, and supplied to other units, with a steam production capacity of approximately 3.6 t / h. The fire-tube waste heat boiler has a horizontal structure, consisting of a right-side tube box, a left-side tube box, and a shell-side shell. The right-side tube box is made of Q345R (normalized) with a diameter of Φ1832; the left-side tube box is made of 15CrMoR (normalized + tempered) with a diameter of Φ2560; and the shell-side shell is made of Q345R (normalized) with a diameter of Φ1750.

[0003] The manufacturing process of fire-tube waste heat boilers is characterized by multiple heat treatments for welds and a large number of flaw detections. Therefore, the assembly sequence is very important. If the assembly sequence is not reasonable, it will increase the number of local heat treatments, or the welds may be unable to be operated due to space constraints and have to be re-welded. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide an optimized manufacturing process for horizontal fire-tube waste heat boilers, and to develop detailed processing and inspection procedures to ensure better coordination and cooperation among components during manufacturing and assembly, thereby guaranteeing quality requirements.

[0005] This invention provides an optimized manufacturing process for a horizontal fire-tube waste heat boiler, comprising the following steps:

[0006] Right-side pipe box manufacturing:

[0007] S1. The diameter of the right-side tube box is rolled according to the standard of shell side tube diameter + 2mm;

[0008] S2. When welding accessories onto the cylinder of the right-side pipe box, do not weld the valve port pipe temporarily.

[0009] Left side tube box manufacturing:

[0010] S3. A fitting hole is made in the rear ring plate of the left side tube box. The diameter of the fitting hole is set according to the standard of the shell side cylinder diameter + 4mm.

[0011] The shell-side cylindrical body is manufactured as follows:

[0012] S4. Measure the deviation of the outer diameter of the heat exchange tube to determine the deviation of the tube hole to be opened on the tube sheet;

[0013] S5. Measure the diameter of the center tube. The diameter of the center hole of the tube sheet shall be opened according to the standard of center tube diameter + 2mm.

[0014] Overall assembly:

[0015] S6. The right-side tube box and the left-side tube box are sequentially fitted onto the shell-side cylinder;

[0016] S7. The valve port connector is fitted with the branch pipe of the heat-resistant tee pipe through a circumferential seam.

[0017] Furthermore, after the cylinder of the left-side tube box is rolled, it is fitted with an anti-deformation support fixture, and then the hole-opening operation and welding of accessories are carried out in sequence.

[0018] Furthermore, a back pad is added when welding Φ2100 and Φ1900 ​​pipes onto the cylinder of the left side box.

[0019] Furthermore, the flange of the Φ2100 pipe is provided with a secondary machining allowance, and the sealing surface is re-machined after the fillet weld is welded to the body of the Φ2100 pipe.

[0020] Furthermore, the heat exchange tubes are horizontally welded to the tube sheet, and the structural design requirements are met by mechanical tube expansion.

[0021] Furthermore, the circumferential and fillet welds of the tube sheet are simultaneously heat-treated using a pressure furnace door.

[0022] Furthermore, in step S7, the heat-resistant tee pipe is fitted with an end plate.

[0023] Furthermore, the ceramic fiber felt of the left-side tube box is made of high-temperature resistant material in sections, and adjacent ceramic fiber felts are connected by interlocking joints.

[0024] Furthermore, the inner wall of the right-side tube box within a region 200mm from its end is subjected to a smoothing process.

[0025] Beneficial effects: The present invention provides an optimized manufacturing process for a horizontal fire-tube waste heat boiler. By analyzing and identifying the difficulties in the manufacturing process, a reasonable welding sequence is formulated, assembly tooling is prepared, and dimensional allowances are pre-set. This enables the rapid and efficient completion of the production of each component in the actual production process, including cold and hot processing, forming, assembly, welding, and inspection, while ensuring product quality. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0027] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0028] like Figure 1As shown, the present invention provides an optimized manufacturing process for a horizontal fire-tube waste heat boiler, comprising the following steps:

[0029] Right-side pipe box manufacturing:

[0030] S1. The diameter of the right-side tube box is rolled according to the standard of shell side tube diameter + 2mm, which facilitates subsequent assembly with the shell side tube.

[0031] S2. When welding accessories onto the cylinder of the right-side pipe box, do not weld the valve port pipe for the time being.

[0032] The rest of the manufacturing process for the right-side tube box is carried out according to the standard procedures, and the specific standard procedures will not be described in detail here.

[0033] Left side tube box manufacturing:

[0034] S3. Make a fitting hole on the rear ring plate of the left tube box. The diameter of the fitting hole should be made according to the diameter of the shell-side cylinder + 4mm to facilitate subsequent fitting with the shell-side cylinder.

[0035] The rest of the manufacturing process for the left-side tube box follows the standard procedures, and the specific standard procedures will not be repeated here.

[0036] Shell side cylinder manufacturing:

[0037] S4. Measure the deviation of the outer diameter of the heat exchange tube to determine the deviation of the tube hole to be opened on the tube sheet.

[0038] S5. Measure the diameter of the center tube. The diameter of the center hole of the tube sheet shall be opened according to the standard of center tube diameter + 2mm.

[0039] The other manufacturing processes for the shell side are carried out according to the standard procedures, and the specific standard procedures will not be described in detail here.

[0040] Overall assembly:

[0041] S6, the right-side tube box and the left-side tube box are sequentially fitted onto the shell-side cylinder.

[0042] S7. Valve port connector and heat-resistant tee pipe branch circumferential seam fitting.

[0043] The rest of the overall assembly process follows the standard procedures, which will not be elaborated here.

[0044] In one embodiment, after the left-side tube box is rolled, an anti-deformation support fixture is installed, followed by drilling and welding of accessories. This better ensures that the left-side tube box does not deform after rolling and during welding.

[0045] In one embodiment, a back pad is added when welding large pipes such as Φ2100 pipes and Φ1900 ​​pipes onto the cylinder of the left side box.

[0046] In one embodiment, the flange of the Φ2100 pipe is provided with a secondary machining allowance. After the fillet weld is installed with the body of the Φ2100 pipe, the sealing surface is re-machined. This is more conducive to eliminating welding and heat deformation and facilitating assembly.

[0047] In one embodiment, the heat exchange tubes are horizontally welded to the tube sheet, and the structural design requirements are met by mechanical tube expansion. This allows for short-distance expansion joints to the tube sheet (L≤10mm) and better ensures weld quality.

[0048] In one embodiment, the circumferential and fillet welds of the tube sheet are simultaneously heat-treated using a furnace door.

[0049] In one embodiment, in step S7, the heat-resistant tee pipe is fitted with an end plate to facilitate the RT flaw detection requirements of each circumferential seam of the heat-resistant tee pipe.

[0050] In one embodiment, the ceramic fiber felt of the left-side tube box is made of high-temperature resistant material in sections, and adjacent ceramic fiber felts are connected by interlocking joints.

[0051] In one embodiment, the inner wall of the right-side tube box within a 200mm radius from its end is smoothed to a rounded shape. Because the cylinder rolling process results in an elliptical shape, and the welded nozzles on the cylinder deform after welding, affecting the end of the assembly, the inner wall of the cylinder is smoothed on a vertical lathe to facilitate assembly.

[0052] The beneficial effects achieved by this invention are as follows:

[0053] 1. The valve port connector in the right-side pipe box is reassembled during the overall assembly. This post-assembly makes it easier to connect the valve port connector with the heat-resistant tee pipe inside the shell-side cylinder.

[0054] 2. The diameter of the cylinder of the right-side pipe box, the diameter of the mounting hole on the rear ring plate of the left-side pipe box, and the allowance for secondary machining of the flange of the Φ2100 pipe are more conducive to eliminating welding and thermal deformation and facilitating assembly.

[0055] 3. The anti-deformation support fixture better ensures that the cylinder of the left-side tube box is not deformed after rolling and during the welding process.

[0056] 4. Mechanical tube expansion is used to meet structural design requirements. This allows for short-distance expansion joints of the tube sheet (L≤10mm) and better ensures weld quality.

[0057] 5. The heat-resistant tee is fitted with an end plate at the rear to facilitate RT flaw detection of each circumferential seam of the heat-resistant tee.

[0058] 6. Using high-temperature resistant ceramic fiber felt with matching performance is more conducive to assembly, avoiding the damage and uneven filling of the original ceramic fiber felt during assembly.

[0059] 7. Perform heat treatment on some weld seams simultaneously to better achieve energy reduction and efficiency improvement.

[0060] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0061] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An optimized manufacturing process for a horizontal fire-tube waste heat boiler, characterized in that: Includes the following steps: Right-side pipe box manufacturing: S1. The diameter of the right-side tube box is rolled according to the standard of shell side tube diameter + 2mm; S2. When welding accessories onto the cylinder of the right-side pipe box, do not weld the valve port pipe temporarily. Left side tube box manufacturing: S3. A fitting hole is opened in the rear ring plate of the left side tube box. The diameter of the fitting hole is set according to the standard of the shell side cylinder diameter + 4mm. The shell-side cylindrical body is manufactured as follows: S4. Measure the deviation of the outer diameter of the heat exchange tube to determine the deviation of the tube hole to be opened on the tube sheet; S5. Measure the diameter of the central tube. The diameter of the central hole of the tube sheet shall be opened according to the standard of central tube diameter + 2mm. Overall assembly: S6. The right-side tube box and the left-side tube box are sequentially fitted onto the shell-side cylinder; S7. The valve port connector is fitted with the branch pipe of the heat-resistant tee pipe through a circumferential seam. After the cylinder of the left-side tube box is rolled, it is installed into the anti-deformation support fixture, and then the hole opening operation and welding of accessories are carried out in sequence. The heat exchange tubes are horizontally welded to the tube sheet, and the structural design requirements are met by mechanical tube expansion. The circumferential and fillet welds of the tube sheet are simultaneously heat-treated using a pressure furnace door method; In step S7, the heat-resistant tee pipe is fitted with an end plate; The inner wall of the right-side tube box within a 200mm radius from its end is smoothed.

2. The optimized manufacturing process for a horizontal fire-tube waste heat boiler according to claim 1, characterized in that: When welding Φ2100 and Φ1900 ​​pipes onto the cylinder of the left-side pipe box, a back pad is added.

3. The optimized manufacturing process for a horizontal fire-tube waste heat boiler according to claim 2, characterized in that: The flange of the Φ2100 pipe is reserved for secondary machining. After the fillet weld is installed with the body of the Φ2100 pipe, the sealing surface is re-machined.

4. The optimized manufacturing process for a horizontal fire-tube waste heat boiler according to claim 1, characterized in that: The ceramic fiber felt of the left-side pipe box is made of high-temperature resistant material in pieces, and the adjacent ceramic fiber felts are connected by a locking mechanism.

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