Guiding tool for extracting and reassembling finned tube at convection section of cracking furnace
By designing a conical guide tool for the convection section of the cracking furnace, the problem of difficulty in passing through the tube plate during the replacement process is solved, and the finned tube that smoothly passes through the tube plate in blind view is realized. The replacement process is simple, ensuring the safe production and process production of the cracking furnace.
Patent Information
- Application Number
- CN202420499355.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-14
- Publication Date
- 2025-03-04
- Estimated Expiration
- 2034-03-14
AI Technical Summary
During the process of replacing the fin tube in the convection section of the cracking furnace, due to the length and gravity of the fin tube, it is difficult to smoothly pass through the pipe holes of the middle tube plate and the end tube plate without being visible, resulting in inconvenient replacement.
A tapered guide tooling is designed, including a sleeve section and a tapered guide section. The tip of the tapered guide section is connected to the guide chain and the sleeve section is connected to the fin tube. It has a guiding role when passing through the pipe hole through the tapered surface to ensure that the fin tube maintains its correct position during the replacement process.
The finned tube that passes through the tube plate smoothly in blind vision is achieved, and the replacement process is simple, which avoids installation difficulties caused by sagging or lifting of the finned tube, ensuring the safe production and process production of the cracking furnace.
Smart Images
Figure CN222556879U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of cracking furnace device replacement, in particular to a guide tool for extracting and reinstalling fin tubes of a cracking furnace convection section. Background Art
[0002] The ethylene cracking furnace is the core equipment of the ethylene production unit, which is divided into a convection section and a radiation section. The convection section is used to recover the waste heat of the flue gas to preheat the raw materials. The cracking furnace includes multiple waste heat recovery modules. The cracking furnace is prone to abnormal rapid coking on the inner wall of the furnace tube during service. During the coking process, the deposited salt is adsorbed by the coke, and molten salt corrosion occurs on the inner wall of the furnace tube, causing the tube wall to thin. If the tube thins severely, it needs to be replaced in time.
[0003] The waste heat recovery module has a total of 8×8 groups of pipelines, that is, 8 layers, 8 tubes per layer, a total of 64 fin tubes with a length of 23 meters. The east and west sides of the module are furnace wall panels, and the north and south are tube boxes. The length of the north and south tube boxes is 23m, and the internal distance is unequal. Four tube sheets are installed vertically to support the fin tubes. The spacing between the tube sheets and the tubes is 3mm, and the internal situation cannot be seen from any direction. When pulling out and replacing the fin tubes, it is necessary to ensure that the fin tubes will not sag or lift up during the reinstallation process, resulting in the tube mouth being unable to pass through the tube holes of the two intermediate tube sheets and the two end tube sheets. In view of this situation, it is urgent to design a guide tool to ensure that the fins can pass through the intermediate tube sheet smoothly without being seen to reach the replacement purpose. Utility Model Content
[0004] According to the technical problems raised above, a guide fixture is provided for extracting and reinstalling the fin tubes of the convection section of a cracking furnace. Aiming at the inconvenience in the replacement process, the utility model designs a conical guide fixture combination to ensure that the fins can pass through the intermediate tube plate smoothly without being seen to achieve the purpose of replacement.
[0005] The technical means adopted by the utility model are as follows:
[0006] A guide fixture for extracting and reinstalling finned tubes of a cracking furnace convection section comprises a sleeve section and a guide section, wherein the end of the guide section is connected to the sleeve section, the sleeve section can be connected to the finned tubes of the cracking furnace convection section to be processed, the outer diameter of the sleeve section matches the inner diameter of the finned tubes of the cracking furnace convection section to be processed, the end of the guide section is tapered, and the tip of the tapered section is used to be connected to a guide chain.
[0007] Furthermore, it also includes a light pipe section, the end of the guide section is connected to the front end of the light pipe section, and a conical sleeve is provided at the rear end of the light pipe section. A connecting space for connecting the finned tubes of the convection section of the cracking furnace to be processed is formed between the inside of the conical sleeve and the outside of the light pipe section.
[0008] Furthermore, a cylindrical hole is opened inside the middle and rear section of the guide section, and a hole with a smaller diameter than that of the hole in the middle and rear section is opened at the middle and front end of the guide section.
[0009] Furthermore, the guide section is also provided with an extension section matching the length of the sleeve section, and a connection space for connecting the finned tubes of the cracking furnace convection section to be processed is formed between the inside of the extension section and the outside of the sleeve section.
[0010] The utility model has the following advantages: Aiming at the working condition that the extraction and reinstallation of the super-long finned tubes in the convection section of the cracking furnace are blocked by the tube holes of the tube sheet due to the drooping due to gravity, the utility model designs a conical guide head as a tool to guide the tube head, protect the fins to pass through the tube sheet to complete the replacement of the finned tube, eliminate the hidden dangers of safe production of the cracking furnace, and ensure process production. The conical surface of the tool has a guiding effect when passing through the tube hole, and the 22.5-meter-long finned tube can pass through the tube sheet in the blind field.
[0011] Specifically, after the fin tube enters the tube box, it is difficult to simultaneously apply upward and forward forces to the 23m long fin tube to keep it moving forward while maintaining its height. After installing the utility model conical guide fixture, it is only necessary to apply two fixed points on the fin tube outside the tube box with a fall chain while maintaining the thrust. In this way, even if the fin tube droops or rises slightly, the conical fixture can decompose the thrust part into a force toward the center when the outer side of the cone contacts the inner side of the tube mouth, thereby completing the guiding function. The utility model is low-cost, simple, practical, and reusable. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.
[0013] Figure 1 This is a schematic diagram of the inlet end tooling of working condition A in the embodiment of the utility model;
[0014] Figure 2 This is a schematic diagram of the tooling at the outlet end of working condition B in the embodiment of the utility model;
[0015] In the figure: 1, guide section; 2, sleeve section; 3, fin tube; 4, smooth tube section. DETAILED DESCRIPTION
[0016] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0017] The waste heat recovery module of the convection section of the cracking furnace is a square tube box template. There are 8 groups of feed preheating pipelines inside the module. Each group of preheating pipelines consists of 8 pipelines stacked in series from top to bottom. The ends of the pipelines are connected by 180° elbows and welded to form a group of independent preheating pipelines. There are a total of 64 pipelines inside the module. The length of the tube box module is 23m. The 4 vertical tube sheets in the middle are used to support the finned tubes to ensure that they do not sag after heating. When replacing the finned tubes, the 180° elbow welds at both ends must be cut off and pulled out. When threading the tubes, a set of conical tooling is designed as a guide for threading the tubes. To this end, the utility model embodiment discloses a guide fixture for extracting and reinstalling the fin tubes of the convection section of a cracking furnace, including a sleeve section 2 and a guide section 1, the end of the guide section is connected to the sleeve section, the sleeve section can be connected to the fin tube 3 of the convection section of the cracking furnace to be processed, the outer diameter of the sleeve section matches the inner diameter of the fin tube of the convection section of the cracking furnace to be processed, the end of the guide section is conical, and the tip of the cone is used to connect to the guide chain. Specifically, the guide device chain or wire rope directly passes through the guide section of the fixture. The end of the guide section referred to in this embodiment is connected to the sleeve section, and specifically the inner diameter of the fixture is larger than the fin tube, so that it can be directly sleeved on the fin tube. Specifically, as Figure 1 As shown, the inner diameter of the tooling is 170.3 mm and the inner diameter of the fin tube is 165.3 mm.
[0018] Specifically, as an implementation of working condition A, it also includes a light pipe segment 4, the end of the guide segment is connected to the front end of the light pipe segment, and a conical sleeve is provided at the rear end of the light pipe segment. A connecting space for connecting the finned tubes of the convection section of the cracking furnace to be treated is formed between the inside of the conical sleeve and the outside of the light pipe segment.
[0019] Furthermore, a cylindrical hole is opened inside the middle and rear section of the guide section, and a hole with a smaller diameter than that of the hole in the middle and rear section is opened at the middle and front end of the guide section.
[0020] Specifically, Figure 2 As shown, as an implementation of working condition B, the guide section is also provided with an extension section matching the length of the sleeve section, and a connecting space for connecting the fin tubes of the cracking furnace convection section to be processed is formed between the inside of the extension section and the outside of the sleeve section.
[0021] The division of working conditions A and B is mainly due to the different distances between the fins of the two specifications of finned tubes and the outside of the steel pipe, so different forms of tooling are designed respectively.
[0022] When extracting the original fin tube, tie the wire rope at the end of the fin tube, and when the pipe is pulled out, the wire rope will also pass through the tube sheet. Then when replacing the new fin tube, just pass it through the new fin tube tooling guide. After the new tube is in place and exposed to the outside, directly remove the wire rope, and the replacement of the fin tube is completed.
[0023] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.
Claims
1. A guide fixture for extracting and reinstalling fin tubes in the convection section of a cracking furnace, characterized in that: It comprises a sleeve section and a guide section, wherein the end of the guide section is connected to the sleeve section, the sleeve section can be connected to the fin tube of the convection section of the cracking furnace to be processed, the outer diameter of the sleeve section matches the inner diameter of the fin tube of the convection section of the cracking furnace to be processed, the end of the guide section is conical, and the tip of the cone is used to be connected to the guide chain.
2. The guide fixture for extracting and reinstalling the fin tubes of the convection section of a cracking furnace according to claim 1, characterized in that: It also includes a light pipe section, the end of the guide section is connected to the front end of the light pipe section, and a conical sleeve is provided at the rear end of the light pipe section. A connecting space for connecting the finned tubes of the cracking furnace convection section to be processed is formed between the inside of the conical sleeve and the outside of the light pipe section.
3. The guide fixture for extracting and reinstalling the fin tubes of the convection section of a cracking furnace according to claim 2, characterized in that: A cylindrical hole is opened inside the middle and rear section of the guide section, and a hole with a smaller diameter than the hole in the middle and rear section is opened at the middle and front end of the guide section.
4. The guide fixture for extracting and reinstalling the fin tubes of the convection section of a cracking furnace according to claim 1, characterized in that: The guide section is also provided with an extension section matching the length of the sleeve section, and a connection space for connecting the finned tubes of the cracking furnace convection section to be processed is formed between the inside of the extension section and the outside of the sleeve section.