A pipeline installation method for propane dehydrogenation projects

Abstract

This invention belongs to the field of pipeline installation and construction technology, specifically relating to a pipeline installation and construction method for propane dehydrogenation projects. The method includes the following steps: pipeline component inspection, pipeline component numbering, preliminary pipeline installation, pipeline re-measurement, and pipeline welding; wherein the preliminary pipeline installation steps further include vertical pipe section installation, tooling laying, pipe fitting transfer, and horizontal pipe section installation. This invention provides clear and reasonable operational steps, standardizes the pipeline installation and construction method for propane dehydrogenation projects, ensures that the pipeline installation and construction quality meets design requirements, improves construction efficiency, and forms a complete and systematic pipeline installation and construction technology for propane dehydrogenation projects.

Description

Technical Field

[0001] This invention belongs to the field of pipeline installation and construction technology, and specifically relates to a pipeline installation and construction method for propane dehydrogenation projects. Background Technology

[0002] Propane dehydrogenation refers to the production process of propylene from propane feedstock through a catalytic dehydrogenation reaction. It has become a popular propylene production technology in recent years. (Reference) Figures 1-3 As shown, the reaction unit in a propane dehydrogenation project mainly consists of multiple reactors 1 arranged side-by-side and a piping system connecting the reactors 1. In a certain propane dehydrogenation project, the reaction unit includes eight reactors 1, but it is understood that the number of reactors 1 is not limited to this. Reactors 1 are typically horizontal tank-like structures, with multiple outlets at the bottom of each reactor 1, including hydrocarbon outlets 11, air outlets 12, and vacuum ports 13. It should be noted that the multiple hydrocarbon outlets 11, air outlets 12, and vacuum ports 13 of the reaction unit are arranged collinearly. The piping system includes three sets of pipes 3, which are used to connect the multiple hydrocarbon outlets 11, air outlets 12, and vacuum ports 13, respectively. Each set of pipes 3 can be divided into horizontal pipe sections and multiple vertical pipe sections that are connected one-to-one with multiple reactors 1. The horizontal pipe sections are mainly welded together by multiple tee pipes 32, multiple expansion joints 33 and multiple connecting pipes 34. The vertical pipe sections include vertical pipes 31. The upper end of the vertical pipe 31 is connected to the gas outlet of the reactor 1 through a special valve 2, and the lower end of the vertical pipe 31 is connected to the tee pipe 32, thereby realizing the connection between the vertical pipe sections and the horizontal pipe sections, and thus realizing the connection between pipes 3 and multiple reactors 1.

[0003] The propane dehydrogenation unit has a unique process, with numerous large-diameter pipes and expansion joints (33) in its reaction units. The piping system operates at high temperatures, approximately 500℃-650℃. The diameters of various pipes are typically over 1 meter, and the expansion joints (33) weigh between 2.4 tons and 65 tons, made of 321H steel, making welding difficult and pipeline installation challenging. Furthermore, the more reactors (1) there are, the greater the difficulty of pipeline installation. If the piping system is not installed correctly, pipelines (3) are prone to excessive axial and angular displacement due to thermal expansion during high-temperature operation, leading to weld tearing or flange misalignment, and ultimately, media leakage and fire. Therefore, the pipeline installation of the reaction units is a crucial aspect of the entire propane dehydrogenation project. However, the pipeline installation in existing or under-construction propane dehydrogenation projects in China is currently unregulated, with unsystematic installation processes and inadequate quality control, posing potential safety hazards for subsequent propane dehydrogenation production. Summary of the Invention

[0004] To address the shortcomings of related technologies, this invention provides a pipeline installation method for propane dehydrogenation projects, aiming to standardize pipeline installation methods for propane dehydrogenation projects, ensure that pipeline installation quality meets design requirements, and improve construction efficiency.

[0005] The pipeline installation method for propane dehydrogenation projects of the present invention includes the following steps:

[0006] S1. Piping component inspection: Conduct quality inspection of piping components according to design requirements; piping components include vertical pipes, tees, expansion joints, connecting pipes, and special valves.

[0007] S2. Pipe assembly numbering: Allocate pipe assemblies according to the quantity and specifications specified in the single-line diagram of the piping system, and indicate the pipe system number according to the single-line diagram of the piping system and the sequence number of each pipe assembly according to the assembly sequence;

[0008] S3. Preliminary pipe installation, which includes the following steps:

[0009] S31. For vertical pipe section installation, first connect the special valve to the gas outlet of the reaction unit, and then connect the vertical pipe to the lower end of the special valve.

[0010] S32. Fixture installation: A fixture is installed under each set of vertical pipes to be installed in the reaction unit. The centerline of the fixture along its length is aligned with the line connecting the centers of the multiple vertical pipes. The fixture is equipped with a transmission component, and the transmission direction of the transmission component is consistent with the direction of the line connecting the centers of the multiple vertical pipes.

[0011] S33. Pipe fittings transfer: Arrange the tees, expansion joints and connecting pipes of each set of pipes to be installed on the tooling according to the sequence number, and use the transmission component to transfer the tees, expansion joints and connecting pipes to the installation position at the same time.

[0012] S34. For horizontal pipe section installation, firstly, assemble, adjust, and spot weld the multiple tees of each set of pipes to be installed with the multiple vertical pipes to ensure that the center lines and elevations of the multiple tees of each set of pipes to be installed are consistent; then assemble, adjust, and spot weld the expansion joints with the tees, and assemble, adjust, and spot weld the connecting pipes with the expansion joints.

[0013] S4. Pipeline re-inspection: Re-inspect the verticality deviation of vertical pipe sections, the coaxiality deviation of horizontal pipe sections, and the straightness deviation. If the re-inspection fails, repeat step S3 until the re-inspection passes.

[0014] S5. Pipe welding: After the pipeline re-inspection is qualified, the final welding is carried out between the tee and the vertical pipe, between the tee and the expansion joint, and between the expansion joint and the connecting pipe.

[0015] The above technical solution clarifies and standardizes the pipeline installation and construction methods for propane dehydrogenation projects, ensuring that the pipeline installation and construction quality meets design requirements and greatly improves construction efficiency.

[0016] In some embodiments, in step S31, before connecting the special valve to the outlet of the reaction unit, the contact line color mark of the flange metal ring gasket of the special valve is checked before installation; first, red lead powder is applied to the mounting surface of the flange metal ring gasket, and then it is placed into the sealing groove of the special valve and rotated 45°, requiring that the contact line on the circumference is continuous and uninterrupted and the contact line width is consistent.

[0017] In some embodiments, the hardness of the flange metal ring gasket is less than 185HV, and the hardness of the flange metal ring gasket is 30HB-40HB lower than that of the valve flange.

[0018] In some embodiments, in step S31, when connecting the special valve to the outlet of the reaction unit, after the special valve is hoisted, the parallelism between the special valve flange and the flange at the outlet is adjusted by a chain hoist. The requirements are: the flange parallelism deviation is not greater than 1.5% of the flange outer diameter; the perpendicular deviation between the flange face and the center is not greater than 1mm when the flange diameter is ≤300mm and not greater than 2mm when the flange diameter is greater than 300mm; the bolt holes on the flange are installed across the middle, and the allowable deviation of the bolt hole center distance is ±1mm.

[0019] In some embodiments, in step S1,

[0020] When inspecting the quality of connecting pipes and vertical pipes, the inspection requirements include: the diameter and wall thickness of the pipes must meet the design requirements; the cut surface of the pipes must be flat, the inclination deviation of the cut end face must not exceed 1% of the outer diameter of the pipes and must not exceed 3mm, and the V-shaped bevel angle of the pipes on one side must be 70°-80°.

[0021] When conducting quality inspections on tees, expansion joints, and special valves, the inspection requirements include: 10% of each batch of pipe fittings of the same specification and model shall be randomly selected, with a minimum of one piece; the outer diameter, wall thickness, length, roundness, and flange sealing surface dimensions of the pipe fittings shall meet the design requirements.

[0022] When inspecting the expansion joint, the inspection requirements also include: the weld surfaces of all parts of the expansion joint are free from cracks, incomplete penetration, and lack of fusion; the expansion joint's shipping parts or locating pins are complete and intact, and there is no looseness.

[0023] In some embodiments, step S1 further includes quality inspection of fasteners used for the connection between the special valve and the reaction unit and the connection between the special valve and the vertical pipe; the fasteners include studs and nuts, and the inspection requirements include: spectral analysis is performed on both studs and nuts, 5% of each batch is sampled, and no less than 10 pieces are sampled.

[0024] In some embodiments, in step S34, after the center lines and elevations of the multiple tees of each set of pipes to be installed are aligned, the requirements are: the center line deviation is no more than 3mm and the elevation deviation is less than ±20mm.

[0025] In some embodiments, in step S34, gantry clamps and wedges are used to align the expansion joint and the tee pipe, and the connecting pipe and the expansion joint, with a minimum of 4 sets of gantry clamps and wedges used; during alignment, the alignment of the inner wall of the pipe fitting is the main focus, and the alignment of the outer wall is the secondary focus, with the misalignment of the inner wall being less than 10% of the pipe fitting wall thickness and less than 2 mm.

[0026] In some embodiments, after step S3 is completed, the requirements include: the verticality deviation of the vertical pipe section is not greater than 5‰ of the length of the vertical pipe section and not greater than 30mm; the coaxiality deviation of the horizontal pipe section is not greater than 3mm; and the straightness deviation of the horizontal pipe section is not greater than 3‰ of the length of the horizontal pipe section and not greater than 80mm.

[0027] Based on the above technical solution, the pipeline installation and construction method for propane dehydrogenation projects in this embodiment of the invention has clear and reasonable operation steps, standardizes the pipeline installation and construction method for propane dehydrogenation projects, ensures that the pipeline installation and construction quality meets the design requirements, improves construction efficiency, and forms a complete and systematic pipeline installation and construction technology for propane dehydrogenation projects. Attached Figure Description

[0028] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0029] Figure 1 This is a schematic diagram of the connection structure of the reactor and pipelines in a propane dehydrogenation process.

[0030] Figure 2 for Figure 1 Side view (only the pipe section is shown);

[0031] Figure 3 for Figure 1 A side cross-sectional view (showing only one reactor);

[0032] Figure 4 This is a cross-sectional view of the tooling used in the pipeline installation method for propane dehydrogenation engineering according to the present invention.

[0033] Figure 5 This is a flowchart of the pipeline installation and construction method for propane dehydrogenation engineering according to the present invention.

[0034] In the picture:

[0035] 1. Reactor; 11. Hydrocarbon outlet; 12. Air outlet; 13. Vacuum port; 2. Special valve;

[0036] 3. Pipes; 31. Vertical pipes; 32. Tees; 33. Expansion joints; 34. Connecting pipes;

[0037] 4. Tooling; 41. Frame; 42. Transmission components; 43. Reinforcing ribs. Detailed Implementation

[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0039] In the description of this invention, it should be understood that the terms "center", "lateral", "longitudinal", "upper", "lower", "top", "bottom", "inner", "outer", "front", "rear", "vertical", "horizontal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0040] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0041] refer to Figures 1-5 As shown, the present invention provides a pipeline installation method for propane dehydrogenation projects, comprising the following steps:

[0042] S1. Pipeline component inspection: After the pipeline components used for the installation of pipeline 3 in the propane dehydrogenation project are prefabricated in the factory, the pipeline components are inspected for quality according to the design requirements; the pipeline components include vertical pipe 31, tee pipe 32, expansion joint 33, connecting pipe 34 and special valve 2.

[0043] S2. Pipe assembly numbering: After the pipe assembly has passed inspection, allocate the pipe assembly according to the quantity and specifications specified in the single-line diagram of the piping system, and indicate the pipe system number according to the single-line diagram of the piping system and the sequence number of each pipe assembly according to the assembly sequence.

[0044] S3, the preliminary installation of pipeline 3, is carried out after all reactors 1 of the propane dehydrogenation reaction unit have been installed. At this time, all reactors 1 of the reaction unit are arranged side by side, all hydrocarbon outlets 11 of the reaction unit are collinear, all air outlets 12 are also collinear, and all vacuum ports 13 are also collinear. Based on this, the preliminary installation of the three sets of pipelines 3 of the reaction unit is carried out. The specific steps for the preliminary installation of pipeline 3 include the following:

[0045] S31. Vertical pipe section installation: First, connect multiple special valves 2 one-to-one to all gas outlets of the reaction unit, that is, connect one special valve 2 to each hydrocarbon outlet 11, air outlet 12, and vacuum port 13; then connect vertical pipes 31 one-to-one to the lower end of the special valves 2. It can be understood that the upper end of the vertical pipe 31 is connected to the lower end of the special valve 2, and the vertical pipe 31 after connection is in a vertical state.

[0046] S32. Fixture 4 is laid. A fixture 4 is laid under each set of vertical pipes 31 of the pipeline 3 to be installed in the reaction unit. That is, each fixture 4 extends along the arrangement direction of the multiple vertical pipes 31 of its corresponding set of pipeline 3 to be installed. The centerline of the fixture 4 along its length is aligned with the center line connecting the centers of the multiple vertical pipes 31. Specifically, a horizontal reference line can be set using the steel structure columns on the construction site or directly laid on the ground. By making the distance between the centerline of the fixture 4 and the horizontal reference line equal to the distance between the center line connecting the centers of the multiple vertical pipes 31 and the horizontal reference line, the centerline of the fixture 4 is aligned with the center line connecting the centers of the multiple vertical pipes 31. The fixture 4 is equipped with a transmission component 42. The transmission direction of the transmission component 42 is consistent with the direction of the center line connecting the centers of the multiple vertical pipes 31. The specific structure of the transmission component 42 includes, but is not limited to, a conveyor belt, transmission roller, rolling wheel, sliding rail, etc.

[0047] S33. Pipe fitting transfer: All the tees 32, expansion joints 33, and connecting pipes 34 required for each set of pipes 3 to be installed are arranged in sequence on the tooling 4. The tees 32, expansion joints 33, and connecting pipes 34 are simultaneously transferred to the installation position using the transmission component 42. It can be understood that at this time, the tees 32 are located one-to-one below the vertical pipes 31. This achieves one-time transfer of the pipe fittings required for each set of pipes 3 to be installed, avoiding frequent labor and handling errors of individual pipe fittings, and improving the efficiency of pipe installation.

[0048] S34. Horizontal pipe section installation: First, assemble, adjust, and spot weld the multiple tees 32 of each set of pipes 3 to be installed with the multiple vertical pipes 31 to ensure that the center lines and elevations of the multiple tees 32 of each set of pipes 3 are consistent, thus achieving the initial installation positioning between the vertical pipes 31 and the tees 32; then, using the tees 32 as fixed ends, assemble, adjust, and spot weld the expansion joints 33 to the tees 32, and assemble, adjust, and spot weld the connecting pipes 34 to the expansion joints 33; specifically, assemble the two... The expansion joints 33 are aligned and tack-welded to the two ends of the tee pipe 32. Then, the two connecting pipes 34 are aligned, aligned, and tack-welded to the two expansion joints 33. This process is repeated until the connection of the entire horizontal pipe section is completed. It is understood that during this process, the axial direction of the expansion joints 33 and the connecting pipes 34 needs to be aligned with the axial direction of the tee pipe 32 to ensure the coaxiality and straightness of the horizontal pipe section. This completes the initial installation and positioning of the tee pipe 32, expansion joints 33, and connecting pipes 34.

[0049] S4. Re-measurement of Pipeline 3: After the initial installation of Pipeline 3 is completed, the verticality deviation of the vertical pipe section, the coaxiality deviation of the horizontal pipe section, and the straightness deviation are re-measured. If the re-measurement fails, step S3 is repeated. Specifically, the installation of the vertical pipe section can be corrected by adjusting the connection between the special valve 2 and the reaction unit and the vertical pipe 31. The installation of the horizontal pipe section can also be corrected by removing the spot welds and re-adjusting and spot welding the tee pipe 32, expansion joint 33, and connecting pipe 34. After the above adjustments are completed, Pipeline 3 is re-measured again until the re-measurement of Pipeline 3 is qualified, thereby ensuring that the initial installation quality of Pipeline 3 meets the design requirements.

[0050] S5. Welding of Pipeline 3: After Pipeline 3 passes the re-inspection, the final welding is carried out between the tee pipe 32 and the vertical pipe 31, between the tee pipe 32 and the expansion joint 33, and between the expansion joint 33 and the connecting pipe 34, thereby completing the installation of Pipeline 3 for the propane dehydrogenation project. It should be noted that the specific welding process and welding method are well known to those skilled in the art and will not be described in detail here.

[0051] It should be noted that during hoisting and installation of the connecting pipe 34 and expansion joint 33, it is strictly forbidden to remove the locking or reinforcement measures of the expansion joint 33. These measures should be removed uniformly after the installation of the pipeline 3 is completed. In addition, the upper pipe opening on the tee pipe 32 that connects to the vertical pipe 31 should be reserved with a length, and the bevel should be prefabricated and trimmed on-site according to the bevel angle of the vertical pipe 31.

[0052] The above illustrative embodiments clearly and standardize the pipeline installation and construction method for propane dehydrogenation projects, accelerate the installation and construction progress, greatly improve construction efficiency, and ensure that the installation and construction quality of pipeline 3 meets the design requirements. This avoids the situation where axial displacement and angular displacement exceed the standard when pipeline 3 is running at high temperature, and also avoids potential safety hazards to subsequent production.

[0053] refer to Figure 1 As shown, in some embodiments, in step S31, before connecting the special valve 2 to the outlet of the reaction unit, a pre-installation contact line color mark inspection is performed on the flange metal ring gasket of the special valve 2. First, red lead powder is applied to the mounting surface of the flange metal ring gasket, and then it is placed into the sealing groove of the special valve 2 and rotated 45°, requiring that the contact line on the circumference is continuous and uninterrupted with a consistent contact line width. This illustrative embodiment clarifies the inspection method and requirements for the flange metal ring gasket of the special valve 2, ensuring that it meets the requirements for the installation and construction of the pipeline 3.

[0054] In some embodiments, the hardness of the flange metal ring gasket is less than 185HV, and the hardness of the flange metal ring gasket is 30HB-40HB lower than the hardness of the flange of valve 2. This illustrative embodiment clarifies the hardness index of the flange metal ring gasket of valve 2, ensuring that the flange metal ring gasket can meet the requirements of pipeline 3 installation and construction.

[0055] refer to Figure 1 As shown, in some embodiments, in step S31, when connecting the special valve 2 to the outlet of the reaction unit, after the special valve 2 is hoisted, the parallelism between the flange of the special valve 2 and the flange at the outlet is adjusted by a chain hoist. The requirements are: the flange parallelism deviation is not greater than 1.5% of the flange outer diameter; the perpendicular deviation between the flange face and the center is not greater than 1mm when the flange diameter is ≤300mm, and not greater than 2mm when the flange diameter is greater than 300mm; the bolt holes on the flange are installed across the center, and the allowable deviation of the bolt hole center distance is ±1mm. This illustrative embodiment clarifies the installation quality control requirements of the special valve 2, that is, it clarifies the quality control requirements of a key process in the installation of pipeline 3, thereby providing early quality assurance for the subsequent installation of other pipes or fittings.

[0056] In some embodiments, in step S1,

[0057] When inspecting the quality of connecting pipe 34 and vertical pipe 31, the inspection requirements include: the diameter and wall thickness of the pipes meet the design requirements; the cut surface of the pipes is flat, the inclination deviation of the cut end face is not greater than 1% of the outer diameter of the pipe and not more than 3mm, and the V-shaped bevel angle of the pipe on one side is 70°-80°.

[0058] When conducting quality inspections on tee pipe 32, expansion joint 33, and special valve 2, the inspection requirements include: 10% of each batch of pipe fittings of the same specification and model shall be randomly selected, with a minimum of 1 piece; the outer diameter, wall thickness, length, roundness, and flange sealing surface dimensions of the pipe fittings shall meet the design requirements.

[0059] When inspecting the expansion joint 33, the inspection requirements also include: the weld surfaces of each part of the expansion joint 33 are free of cracks, incomplete penetration and incomplete fusion; the shipping parts or locating pins of the expansion joint 33 are complete and intact, and there is no looseness.

[0060] The above illustrative embodiments clarify the inspection methods and requirements for each pipeline component, ensuring that each pipeline component can meet the installation and construction requirements of pipeline 3.

[0061] In some embodiments, step S1 further includes quality inspection of the fasteners used for the connection between the special valve 2 and the reaction unit, and the connection between the special valve 2 and the vertical pipe 31. The fasteners include studs and nuts, and the inspection requirements include: performing spectral analysis on both studs and nuts, sampling 5% of each batch, with a minimum of 10 pieces. This illustrative embodiment clarifies the inspection method for fasteners, ensuring that the fasteners meet the requirements for the installation and construction of the pipeline 3.

[0062] refer to Figure 1 , Figure 2 As shown, in some embodiments, in step S34, after adjusting the center lines and elevations of the multiple tee pipes 32 of each set of pipes to be installed to be consistent, the requirements are: the center line deviation of the multiple tee pipes 32 of each set of pipes to be installed is no more than 3mm, and the elevation deviation is less than ±20mm. This illustrative embodiment clarifies the quality requirements after the installation of the tee pipes 32, that is, it clarifies the quality control requirements of a key process in the installation of pipes 3, thereby providing preliminary quality assurance for the installation of other pipe fittings.

[0063] In some embodiments, in step S34, gantry clamps and wedges are used to align the expansion joint 33 with the tee pipe 32 and the connecting pipe 34 with the expansion joint 33. At least four sets of gantry clamps and wedges are used. The wedges include, but are not limited to, oblique wedges and flat wedges. The number of sets of gantry clamps and wedges can be increased according to the actual ellipticity of the pipe fittings. The wedges are made of 300 series stainless steel. During alignment, the alignment of the inner wall of the pipe fitting is the primary focus, with the outer wall alignment as a secondary focus. The inner wall of the pipe fitting must be flush, with the misalignment less than 10% of the pipe fitting wall thickness and less than 2mm. This illustrative embodiment clarifies the quality control requirements for alignment, that is, it clarifies the quality control requirements for a key process in the installation of pipe 3, thereby improving the installation quality of the horizontal pipe section of pipe 3.

[0064] refer to Figures 1-3As shown, in some embodiments, after step S3 is completed, the requirements include: the verticality deviation of the vertical pipe section of each set of pipes 3 is no greater than 5‰ of the length of the vertical pipe section and no greater than 30mm; the coaxiality deviation of the horizontal pipe section of each set of pipes 3 is no greater than 3mm, and the straightness deviation of the horizontal pipe section is no greater than 3‰ of the length of the horizontal pipe section and no greater than 80mm. This illustrative embodiment clarifies the key quality control requirements after the initial completion of the propane dehydrogenation project pipe 3, thereby controlling the installation quality of pipe 3 to ensure that the installation and construction quality of pipe 3 meets the design requirements.

[0065] refer to Figure 3 , Figure 4 As shown, in some embodiments, the tooling 4 further includes a frame 41 and reinforcing ribs 43; the transmission component 42 is connected to the frame 41, and in step S33, the pipe to be conveyed is arranged on the transmission component 42, and the pipe is conveyed by the transmission component 42; the reinforcing ribs 43 are connected between the two side walls of the frame 41 to enhance the overall strength of the tooling 4.

[0066] In summary, the pipeline installation method for propane dehydrogenation projects of this invention has clear and reasonable operation steps, standardizes the pipeline installation method for propane dehydrogenation projects, improves construction efficiency, and clarifies the quality control requirements for several key pipeline installation processes. This ensures that the verticality deviation of vertical pipe sections, the coaxiality deviation of horizontal pipe sections, and the straightness deviation all meet design requirements, thereby ensuring the quality of pipeline installation and construction, avoiding excessive axial and angular displacement during high-temperature operation of the pipeline, and preventing potential safety hazards to subsequent production. Thus, a complete and systematic pipeline installation technology for propane dehydrogenation projects is formed.

[0067] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0068] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A pipeline installation method for propane dehydrogenation projects, characterized in that, Includes the following steps: S1. Pipeline assembly inspection: Conduct quality inspection of pipeline assemblies according to design requirements; the pipeline assemblies include vertical pipes, tees, expansion joints, connecting pipes, and special valves. S2. Pipe assembly numbering: Allocate the pipe assemblies according to the quantity and specifications specified in the single-line diagram of the piping system, and indicate the pipe system number according to the single-line diagram of the piping system and the sequence number of each pipe assembly according to the assembly sequence; S3. Preliminary pipeline installation is carried out after all reactors in the propane dehydrogenation project's reaction unit have been installed. At this time, all reactors are arranged side by side, and all hydrocarbon outlets, all air outlets, and all vacuum ports of the reaction unit are collinear. The preliminary pipeline installation specifically includes the following steps: S31. Vertical pipe section installation: First, connect the multiple special valves to all the gas outlets of the reaction unit, that is, connect one of the special valves to each of the hydrocarbon outlets, air outlets, and vacuum ports. Then, connect the multiple vertical pipes to the lower ends of the multiple special valves. S32. Fixture installation: A fixture is installed under each set of vertical pipes of the pipeline to be installed in the reaction unit. Each fixture extends along the arrangement direction of the corresponding vertical pipes of the pipeline to be installed, and the centerline of the fixture in the length direction is aligned with the center line connecting the centers of the multiple vertical pipes. The fixture is equipped with a transmission component, and the transmission direction of the transmission component is consistent with the direction of the center line connecting the centers of the multiple vertical pipes. S33. Pipe fittings transfer: Arrange all the tees, expansion joints and connecting pipes required for each set of pipes to be installed on the tooling according to the sequence number. Use the transmission component to transfer the tees, expansion joints and connecting pipes to the installation position at the same time. At this time, the tees are located one to one below the vertical pipe. S34. For horizontal pipe section installation, firstly, assemble, adjust, and spot weld the multiple tees of each set of pipes to be installed with the multiple vertical pipes to ensure that the center lines and elevations of the multiple tees of each set of pipes to be installed are consistent; then, using the tees as fixed ends, assemble, adjust, and spot weld the expansion joints to the tees, and assemble, adjust, and spot weld the connecting pipes to the expansion joints until the connection of the entire horizontal pipe section is completed. During this process, the axial direction of the expansion joints and connecting pipes is adjusted to be consistent with the axial direction of the tees. S4. Pipeline re-inspection: Re-inspect the verticality deviation of the vertical pipe section, the coaxiality deviation of the horizontal pipe section, and the straightness deviation; if the re-inspection fails, repeat step S3 until the re-inspection passes. S5. Pipeline welding: After the pipeline re-inspection is qualified, the final welding is carried out between the tee and the vertical pipe, between the tee and the expansion joint, and between the expansion joint and the connecting pipe to complete the pipeline installation construction of the propane dehydrogenation project.

2. The pipeline installation method for propane dehydrogenation projects according to claim 1, characterized in that, In step S31, before connecting the special valve to the outlet of the reaction unit, the contact line color mark of the flange metal ring gasket of the special valve is checked before installation; first, red lead powder is applied to the mounting surface of the flange metal ring gasket, and then it is placed into the sealing groove of the special valve and rotated 45°, requiring that the contact line on the circumference is continuous and uninterrupted and the contact line width is consistent.

3. The pipeline installation method for propane dehydrogenation projects according to claim 2, characterized in that, The hardness of the flange metal ring gasket is less than 185HV, and the hardness of the flange metal ring gasket is 30HB-40HB lower than that of the valve flange.

4. The pipeline installation method for propane dehydrogenation projects according to claim 2, characterized in that, In step S31, when connecting the special valve to the outlet of the reaction unit, after the special valve is hoisted, the parallelism between the special valve flange and the flange at the outlet is adjusted by a chain hoist. The requirements are as follows: the flange parallelism deviation is not greater than 1.5% of the flange outer diameter; the perpendicular deviation between the flange face and the center is not greater than 1mm when the flange diameter is ≤300mm and not greater than 2mm when the flange diameter is greater than 300mm; the bolt holes on the flange are installed across the middle, and the allowable deviation of the center distance between the bolt holes is ±1mm.

5. The pipeline installation method for propane dehydrogenation projects according to claim 1, characterized in that, In step S1, When inspecting the quality of the connecting pipes and vertical pipes, the inspection requirements include: the diameter and wall thickness of the pipes meet the design requirements; the cut surface of the pipes is flat, the inclination deviation of the cut end face is not greater than 1% of the outer diameter of the pipes and does not exceed 3mm, and the V-shaped bevel angle on one side of the pipes is 70°-80°. When conducting quality inspections on the aforementioned tees, expansion joints, and special valves, the inspection requirements include: sampling 10% of each batch of pipe fittings of the same specification and model, with a minimum of one piece; and ensuring that the outer diameter, wall thickness, length, roundness, and flange sealing surface dimensions of the pipe fittings meet the design requirements. When inspecting the expansion joint, the inspection requirements also include: the weld surfaces of each part of the expansion joint are free from cracks, incomplete penetration, and lack of fusion; the expansion joint's shipping parts or locating pins are complete and intact, and there is no looseness.

6. The pipeline installation method for propane dehydrogenation projects according to claim 1 or 5, characterized in that, Step S1 also includes a quality inspection of the fasteners, which are used for the connection between the special valve and the reaction unit and the connection between the special valve and the vertical pipe. The fasteners include studs and nuts, and the inspection requirements include: performing spectral analysis on both studs and nuts, sampling 5% of each batch, and not less than 10 pieces.

7. The pipeline installation method for propane dehydrogenation projects according to claim 1, characterized in that, In step S34, after the center lines and elevations of the multiple tees of each set of pipes to be installed are aligned, the requirements are: the center line deviation is no more than 3mm, and the elevation deviation is less than ±20mm.

8. The pipeline installation method for propane dehydrogenation projects according to claim 1, characterized in that, In step S34, gantry clamps and wedges are used to align the expansion joint and the tee pipe, and the connecting pipe and the expansion joint. At least 4 sets of gantry clamps and wedges are used. When aligning the pipes, the inner wall alignment is the main focus, and the outer wall alignment is secondary. The misalignment of the inner wall is less than 10% of the pipe wall thickness and less than 2mm.

9. The pipeline installation method for propane dehydrogenation projects according to claim 1, characterized in that, After completing step S3, the requirements include: the verticality deviation of the vertical pipe section is not greater than 5‰ of the length of the vertical pipe section and not greater than 30mm; the coaxiality deviation of the horizontal pipe section is not greater than 3mm; and the straightness deviation of the horizontal pipe section is not greater than 3‰ of the length of the horizontal pipe section and not greater than 80mm.

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