JP5058558B2 - Pyrolysis furnace tube assembly method - Google Patents

Description

  The present invention relates to a method for assembling a pyrolysis furnace tube, and more particularly to a method capable of greatly shortening the working days.

  For example, when producing an olefinic compound, a diluent such as water vapor is added to a saturated hydrocarbon of ethane, propane, butane, pentane, naphtha or a mixture thereof and supplied to a pyrolysis furnace, and the olefinic compound is obtained by pyrolysis. Is obtained (Patent Literature 1, Patent Literature 2).

  For example, as shown in FIG. 3, in the above-mentioned pyrolysis furnace, a plurality of U-shaped coil tubes 100B are passed over two large-diameter header tubes 100A that are parallel to each other, and both ends thereof are connected to the header tubes 100A. A system is known in which the pyrolysis furnace tube 100 is configured by communication and connection, and a plurality of pyrolysis furnace tubes 100 are built in the furnace.

  By the way, when assembling the above-described pyrolysis furnace tube, the header pipe 100A having a length of 10 m to 15 m is carried to the site of the pyrolysis furnace, and the header pipe 100A is taken into the pyrolysis furnace from the opening opened in the pyrolysis furnace. In this case, it is temporarily suspended in a mutually parallel posture, and both ends of a plurality of coil tubes 100B are welded to the header tube 100A as shown in FIGS. In FIG. 5, 100C indicates a nozzle for welding both ends of the coil tube 100B to the header tube 100A, and 100D indicates a welding point when the coil tube 100B is manufactured.

Japanese Patent Laid-Open No. 09-53060 JP-A-62-218486

  However, in the conventional assembly method, the pitch of the coil tube is small, and it is necessary to weld one by one to the header tube, so that the work days until the assembly is completed become very long, and a normal-scale pyrolysis furnace tube However, it took about 90 to 120 days, during which time the operation of the pyrolysis furnace had to be stopped.

  This invention makes it a subject to provide the assembly method of the pyrolysis furnace tube which enabled it to shorten working days significantly in view of this problem.

  The assembling method of the pyrolysis furnace tube according to the present invention is a jig and restraint tool for assembling a pyrolysis furnace tube formed by connecting both ends of a plurality of U-shaped coil tubes to two header pipes. Apply a reverse strain to the header single pipe to reduce welding distortion due to welding of the coil tube, and weld the ends of multiple coil tubes to the header single pipe in this state, then release the restraint by the restraint tool A step of manufacturing a tube block, and taking the plurality of tube blocks into a pyrolysis furnace, and welding a single pipe for a header of the plurality of tube blocks to each other to manufacture a header tube of a predetermined length And a step of assembling a pyrolysis furnace tube from the plurality of tube blocks.

  One of the features of the present invention is that the pyrolysis furnace tube is divided into a plurality of tube blocks, and the tube block is manufactured at the factory, then transported to the pyrolysis furnace, taken into the pyrolysis furnace, and used for the header of the tube block. A single tube is connected to each other to assemble a pyrolysis furnace tube.

  As a result, the weld location at the work site is basically the connection location of the single pipe for the header, which is less than the conventional assembly method, and the quality inspection of the weld can be performed at the factory for multiple tube blocks, As a result of fewer inspections at the work site, the number of work days can be significantly reduced.

  Also, in the conventional assembly method, when welding both ends of the coil tube to the header pipe, it is necessary to assemble a temporary scaffold in the pyrolysis furnace and dismantle after the work, which also leads to an increase in work days. In the present invention, a tube block in which a coil tube is welded to a single pipe for a header is manufactured at the factory, so there is no need to assemble a temporary scaffold in the pyrolysis furnace, and there is no need to assemble / disassemble the scaffold, shortening the work days. it can.

  Furthermore, as a result of reducing the work on the environment, which is not preferable in the environment of the pyrolysis furnace, the safety of the operator can be improved.

  By the way, in the conventional assembly method, a plurality of coil tubes are welded to a header pipe of a predetermined length, and the entire header pipe is distorted by the heat input of welding, but the heat input for correction is applied to an appropriate part of the header pipe. The distortion can be reduced by applying, and the problem does not occur so much.

  On the other hand, when a plurality of coil tubes are welded to the header single pipe as described above, welding distortion remains in the header single pipe due to the heat input of welding, and welding failure occurs when the header single pipes are welded to each other. Not only is it a concern, it requires skill in the work.

  Another feature of the present invention is that the header single pipe is reversely strained by the jig and the restraining tool, and the coil tube is welded to the header single pipe in this state. Thereby, when the restraint is released, the welding distortion and the reverse distortion cancel each other, and a tube block with less welding distortion is obtained. As a result, it is possible to reduce the possibility of poor welding even if the single tube for the header of the tube block is welded.

  In addition, as described above, since the tube block is manufactured at the factory, the quality of the tube block can be inspected at the factory, and only a relatively simple final inspection needs to be performed at the assembly site. This can also simplify the work days.

  Hereinafter, the present invention will be described in detail based on specific examples shown in the drawings. 1 and 2 show a preferred embodiment of a method for assembling a pyrolysis furnace tube according to the present invention. In the pyrolysis furnace tube 100 ′ of this example, a plurality of U-shaped coil tubes 200B are stretched between two large-diameter header tubes 200A parallel to each other, and both ends thereof are welded to the header tubes 200A. The header pipe 200A is manufactured by welding a plurality of header single pipes 200A '.

  When assembling the pyrolysis furnace tube 100 ′ of this example, as shown in FIG. 2A, a header single pipe 200 </ b> A ′, that is, a pipe having a length obtained by dividing the header pipe 200 </ b> A into an appropriate length is prepared. . As shown in FIG. 2B, the header single pipe 200A ′ is placed on a jig 300, and both ends of the header single pipe 200A ′ are placed on the floor by a restraining tool 310 including a chain and a tightening tool. It constrains it and applies reverse strain that reduces the effect of weld strain.

  In this state, the nozzles 200C are welded to a plurality of locations of the header single pipe 200A '. The nozzle 200C is a component for connecting both ends of the coil tube 200B to the header single pipe 200A '. When the welding operation is completed and the restraint of the restraint tool 310 is released, the reverse strain reduces the influence of the weld strain as shown in FIG.

  Thus, when the nozzle 200C is welded to the header single pipe 200A ′, as shown in FIG. 1B, the coil tube 200B is assembled by welding the main body portion, and the main body portion is welded to the nozzle 200C. A tube block 200 shown in FIG. 1 (c) is obtained.

  Both ends of the header single pipe 200A ′ of the tube block 200 can be sealed with a jig, for example, a plate and an air cylinder, and high-pressure air can be supplied to the inside to inspect the quality of the tube block 200 from fluctuations in air pressure. it can. Further, in the process of manufacturing the tube block 200, at the stage where the nozzle 200C is welded to the header single tube 200A ′, the nozzle 200C is sealed with a plug, and the welding operation of the nozzle 200C is performed by performing the same operation as the tube block 200. You can also.

  Assembly and inspection of the tube block 200 described above can be performed at the factory.

  When the tube block 200 is assembled, it is transported to the assembly site of the pyrolysis furnace. Depending on the size of the block, it is transported to the assembly site by truck, trailer or ship. At the assembly site, the tube block 200 is suspended and moved by a crane, for example, a mobile crane, and taken into the furnace through an opening opened in the ceiling of the pyrolysis furnace.

  In this way, the plurality of tube blocks 200 are taken into the pyrolysis furnace, the tube blocks 200 are laid out in the shape of the pyrolysis furnace tube 100 ′, and as shown in FIG. 1 and FIG. When the header single tubes 200A ′ are welded to each other, the pyrolysis furnace tube 100 ′ can be assembled.

  As described above, the tube block 200 in which the pyrolysis furnace tube 100 ′ is divided into a size that can be transported is manufactured in the factory, transported to the assembly site, and the header single pipe 200A ′ of the tube block 200 is welded. Since the pyrolysis furnace tube 100 ′ is assembled by manufacturing the header tube 200A, the number of assembly work days can be reduced.

  Also, in the conventional assembly method, when welding both ends of the coil tube to the header pipe, it is necessary to assemble a temporary scaffold in the pyrolysis furnace and dismantle after the work, which also leads to an increase in the number of work days. In the method of this example, the tube block 200 in which the coil tube 200B is welded to the single pipe for header 200A ′ is produced at the factory, so there is no need to assemble a temporary scaffold in the pyrolysis furnace as in the conventional assembly method. Assembling and dismantling of the scaffold is not necessary, and this also shortens the work days.

  In addition, since the header single pipe 200A 'is reversely strained when the tube coil 200B is welded, there is little welding distortion of the header single pipe 200A', and there is little welding failure when the header pipe 200A is manufactured.

  In addition, since the quality inspection of the tube block 200 is performed at the factory, it is easier than the case where the inspection work is performed in the pyrolysis furnace, and the number of days required for the inspection can be reduced.

  As a result, the number of days required for assembling the pyrolysis furnace tube 100 ′ can be greatly reduced, and the number of days for discontinuing the operation of the pyrolysis furnace can be reduced. As a result, the reduction in the production amount of products due to the operation stop can be greatly reduced.

  In addition, as described above, it is possible to reduce the work on the environment, which is not preferable in the environment of the pyrolysis furnace, and as a result, the safety of the operator can be improved.

It is a schematic diagram which shows preferable embodiment of the assembly method of the pyrolysis furnace tube which concerns on this invention. It is a figure for demonstrating the welding operation | work of the nozzle to the single pipe | tube for headers in the said embodiment. It is a figure which shows the structural example of a pyrolysis furnace. It is a figure which shows the conventional assembly method. It is a figure which shows the conventional assembly method.

Explanation of symbols

100 'pyrolysis furnace tube 200 tube block 200A header tube 200A' header single tube 200B coil tube 200C nozzle 300 jig 310 restraint tool

Claims (1)

When assembling a pyrolysis furnace tube in which both ends of a plurality of U-shaped coil tubes are connected to two header pipes,
Apply a reverse strain that reduces welding distortion caused by welding of the coil tube to the header single pipe using a jig and restraint, and then weld both ends of the multiple coil tubes to the header single pipe in this state, A step of manufacturing a tube block by releasing the restraint by the tool, and taking the plurality of tube blocks into a pyrolysis furnace and welding the single tubes for the headers of the plurality of tube blocks to each other to form a header having a predetermined length Assembling a pyrolysis furnace tube from the plurality of tube blocks by producing a tube;
A method for assembling a pyrolysis furnace tube.

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