TPR steel-plastic composite pipe for conveying desulfurization slurry in thermal power plants

Abstract

The TPR steel-plastic composite pipe for conveying desulfurization slurry in thermal power plants is a type of steel-plastic composite pipe. From the inside out, it includes a composite inner core pipe and a steel pipe. The composite inner core pipe has a three-layer structure: the inner layer is a TPR wear-resistant layer (1), the outer layer is a composite inner core pipe middle layer, the middle layer is a polymer barrier layer (2), and the outer layer is a hot melt adhesive layer (3). The inner wall of the steel pipe (5) is provided with an epoxy resin layer (4). The steel pipe (5) is sleeved on the outside of the composite inner core pipe. The composite inner core pipe and the steel pipe are bonded together by the hot melt adhesive layer (3) and the epoxy resin layer (4). The outer side of the steel pipe is sprayed with a weather-resistant protective layer (6). The inner surface of the TPR wear-resistant layer (1) is provided with spiral diversion reinforcing ribs (7). This improves the conveying and usage efficiency of the system.

Description

Technical Field

[0001] This utility model relates to a steel-plastic composite pipe, and more particularly to a TPR steel-plastic composite pipe for conveying desulfurization slurry in thermal power plants. Background Technology

[0002] The desulfurization slurry produced during the wet desulfurization process in thermal power plants mainly contains sulfites, sulfates, nitrates, carbonates, and mixtures of acids and alkalis. It is typically transported using either metal or non-metal pipelines. This mixture of sulfates and other desulfurization slurries is highly corrosive to metal materials and causes significant wear and tear on metal pipelines during transport, greatly affecting the service life and lifespan of the pipelines. Frequent replacement or repair of the pipelines is necessary, increasing production costs and workload, and sometimes even impacting the normal operation of equipment.

[0003] Compared to metal pipes, ordinary non-metallic pipes are significantly lighter, weighing only 1 / 4 to 1 / 3 the weight of metal pipes; they also possess excellent corrosion resistance, are easy and quick to install, save energy, are convenient to transport, and have low costs. However, due to the inherent characteristics of ordinary non-metallic materials, they also have serious drawbacks: poor toughness, weak pressure and impact resistance, and a large coefficient of linear expansion. Precisely because of the inherent characteristics of organic non-metallic materials, there are significant limitations in the transportation of mineral slurry mixtures such as sulfates. For example, the wear resistance of ordinary non-metallic materials is far from meeting the requirements for mineral slurry transportation pipes, and their pressure-bearing capacity does not meet the pressure requirements for high-pressure pipeline transportation.

[0004] In recent years, the method of lining metal pipes with butyl rubber has partially solved the above-mentioned problems. This type of pipe involves attaching a layer of butyl rubber with good wear resistance to the inner wall of the metal pipe as a wear-resistant and corrosion-resistant layer. A solvent-based liquid adhesive is applied between the inner wall of the metal pipe and the butyl rubber sheet to ensure good adhesion between them. This method of lining metal pipes with butyl rubber combines the advantages of both non-metallic materials and steel pipes, effectively solving the problems of wear and corrosion resistance in pipes, and also addressing the shortcomings of non-metallic pipes being corrosion-resistant but not pressure-resistant, and steel pipes being pressure-resistant but not corrosion-resistant. However, this type of pipe has high production costs and complex processing procedures, especially for small-diameter pipes. Furthermore, the use of solvent-based liquid adhesives during processing generates volatile organic compounds (VOCs) that pose significant harm to the environment and construction workers. Additionally, these solvent-based liquid adhesives are prone to aging, leading to adhesive delamination issues during the use of these rubber-lined metal pipes. This results in the butyl rubber layer separating from the metal pipe, preventing the proper transport of mineral slurry, and causing rapid corrosion of the outer metal layer. This not only severely impacts the normal use and lifespan of the mineral slurry transport pipeline, but also, due to the adhesive detachment causing torn rubber sheets, easily clogs the pipes, creating significant production hazards. Utility Model Content

[0005] The TPR steel-plastic composite pipe for conveying desulfurization slurry in thermal power plants prepared by this utility model adopts a co-extrusion molding process to form a composite inner core pipe with excellent three-layer material compatibility, with TPR new material as the inner layer.

[0006] The TPR steel-plastic composite pipe for conveying desulfurization slurry in thermal power plants consists of a composite inner core pipe and a steel pipe from the inside out. The composite inner core pipe has a three-layer structure: the inner layer is a TPR wear-resistant layer (1), the outer layer is a composite inner core pipe middle layer, the middle layer is a polymer barrier layer (2), and the outer layer is a hot melt adhesive layer (3). The inner wall of the steel pipe (5) is provided with an epoxy resin layer (4), and the steel pipe (5) is sleeved on the outside of the composite inner core pipe. The composite inner core pipe and the steel pipe are bonded together by the hot melt adhesive layer (3) and the epoxy resin layer (4). The outer side of the steel pipe is sprayed with a weather-resistant protective layer (6). The inner surface of the TPR wear-resistant layer (1) is provided with spiral diversion reinforcing ribs (7).

[0007] Furthermore, the spiral flow divider (7) consists of three parallel spiral ribs that spiral along the inner wall of the composite inner core tube.

[0008] Furthermore, at the end of the TPR steel-plastic composite pipe, the composite inner core pipe is longer than the steel pipe (5). The composite inner core pipe is turned outward, that is, the composite inner core pipe is heated and turned over to the flanges at both ends of the steel pipe for connection with the pipeline.

[0009] The TPR wear-resistant layer (1) is made of wear-resistant TPR material, and the thickness of the TPR wear-resistant layer (1) is 1.5-6.0 mm;

[0010] A polymer barrier layer (2) with a thickness of 2.0-6.0 mm effectively slows down the corrosion of steel pipes by the slow penetration of desulfurization slurry;

[0011] The total thickness of the hot melt adhesive layer (3) and the epoxy resin layer (4) is 0.2-0.6 mm. Together, they effectively bond the inner core composite pipe and the steel pipe into a whole without falling off.

[0012] The steel pipe (5) is a welded steel pipe or a seamless steel pipe with a diameter of DN40-DN1200mm, providing the pressure resistance and stiffness requirements for TPR steel-plastic composite pipe;

[0013] The weather-resistant protective layer (6) is composed of weather-resistant polymer (or adhesive material) and can be composed of one or more layers, with a total thickness of 1.0-5.0 mm.

[0014] The spiral diversion reinforcing rib (7) plays a role in diverting and silencing in the composite pipe, and strengthens the rigidity of the inner core composite pipe ring, which improves the protection against the flattening and deformation of the inner core pipe under vacuum. The reinforcing rib has a width of 3.0-8.0 mm and a height of 1.5-5.0 mm. The material of the spiral diversion reinforcing rib (7) is the same as that of the TPR wear-resistant layer (1), and it is integrated with the TPR wear-resistant layer (1).

[0015] The preparation method of the above-mentioned TPR steel-plastic composite pipe for conveying desulfurization slurry in thermal power plants includes the following steps:

[0016] (1) Place the three raw materials of the prepared composite inner core tube into three extruders respectively, control the extrusion temperature, screw speed and extrusion speed respectively, so that the three fully plasticized melts are compounded in the composite co-extrusion die and finally extruded through the die. The inner wall of the die has a groove consistent with the cross section of the spiral diversion reinforcing rib (7) to obtain the inner core composite tube blank.

[0017] The processing temperature of the inner TPR material is 160-180℃; the processing temperature of the middle barrier material is 190-210℃; and the processing temperature of the outer hot melt adhesive is 210-220℃.

[0018] In the process of extruding the inner core composite tube blank, the tube undergoes rotational traction torsion, vacuum shaping, and cooling. The extrusion speed and the rotational speed of the traction are adjusted and controlled, i.e., the value of the extrusion line speed / rotational speed, which is generally 0.5-2 meters / revolution. The specific value is selected according to the tube diameter and the required torsion angle, so that the inner wall reinforcing ribs of the tube are twisted into spiral flow-dividing reinforcing ribs, thus forming an inner core composite tube with spiral flow-dividing reinforcing ribs.

[0019] (2) Surface treatment of steel pipes

[0020] The rust and oxide layer on the inner and outer surfaces of the steel pipe are removed by physical rust removal methods; corresponding epoxy resin or protective materials are then sprayed onto the inner and outer layers.

[0021] (3) Composite of inner core pipe and steel pipe

[0022] The inner core composite tube is appropriately stretched and its diameter reduced by the stretching device, which facilitates its insertion into the steel pipe. Both ends of the inner core tube are sealed, and pressurized air is injected to maintain a pressure of 0.4–0.6 MPa. The medium-frequency heating device is then activated and moved along the steel pipe to heat it, controlling the heating efficiency and moving speed. The temperature is controlled at 180–200℃, and the moving speed at 0.3–0.6 m / min (note the relationship between the medium-frequency heating efficiency and the moving speed; if the inner core tube is too cold or too hot, it will not achieve good adhesion to the steel pipe). Once the inner core composite tube softens and the hot melt adhesive on its outer surface fully adheres to the epoxy resin layer on the inner surface of the steel pipe, cooling water is sprayed promptly to cool and set the inner core composite tube, completing the good adhesion between the inner core composite tube and the steel pipe. Ideally, the adhesion strength between the inner core composite tube and the steel pipe should be ≥100 N / cm.

[0023] The inner layer of the core tube is made of TPR wear-resistant material, providing the wear-resistant performance required for desulfurization slurry transportation. Furthermore, the inner wall of the core tube is designed with three spiral diversion reinforcing ribs, which not only divert and reduce noise during slurry transportation but also significantly improve the ring stiffness of the composite core tube. This provides necessary protection against the vacuum negative pressure generated during slurry transportation, preventing the core tube from being flattened. The middle layer of the core tube is a high-molecular polymer barrier layer, effectively preventing the slow penetration of corrosive desulfurization slurry into the steel pipe and its potential damage. The outer layer of the core tube is a hot-melt adhesive layer. The composite core tube and the epoxy resin sprayed on the inner wall of the steel pipe are bonded together by the hot-melt adhesive, forming an organic whole without any detachment, thus preventing the possibility of pipe blockage. An epoxy resin layer is sprayed onto the outer layer of the steel pipe to enhance its resistance to external environmental corrosion. Finally, at both ends of the steel-plastic composite pipe, an inner core tube is flanged, meaning the inner core tube is heated and flanged onto the flanges at both ends of the steel pipe, forming a closed-loop organic polymer channel. This ensures that the slurry inside the pipe does not come into contact with the steel material, achieving the purpose of wear resistance and corrosion prevention for the steel-plastic composite pipe. Compared with other wear-resistant plastic pipes or steel pipes, TPR steel-plastic composite pipes not only solve the requirements of wear resistance, corrosion resistance, pressure resistance, and durability for desulfurization slurry transportation in thermal power plants, but also possess high strength, high rigidity, and high ring stiffness, significantly improving the pipe's span bending strength, making it suitable for large-span installations.

[0024] In addition, TPR steel-plastic composite pipes are easy to install and save on maintenance costs; at the same time, the TPR material on the inner wall of the steel-plastic composite pipe has a low coefficient of friction, which improves the system's conveying and usage efficiency.

[0025] The TPR steel-plastic composite pipe for conveying desulfurization slurry in thermal power plants is an environmentally friendly product with no VOC emissions or harmful substance release, and it has no impact on the natural environment or production technicians. Attached Figure Description

[0026] Figure 1Schematic diagram of a TPR steel-plastic composite pipe structure for conveying desulfurization slurry in a thermal power plant;

[0027] TPR wear-resistant layer (1), polymer barrier layer (2), hot melt adhesive layer (3), epoxy resin layer (4), steel pipe (5), weather-resistant protective layer (6), spiral diversion reinforcing rib (7);

[0028] The number of outer layers shown in the diagram is not specific and includes, but is not limited to, this number of layers.

[0029] Figure 2 It is a core composite tube mold. Detailed Implementation

[0030] The present invention will be further described below with reference to the embodiments, but the present invention is not limited to the following embodiments.

[0031] Raw materials and performance requirements for TPR steel-plastic composite pipes used in desulfurization slurry transportation in thermal power plants

[0032] 1. TPR steel-plastic composite pipe for desulfurization slurry transportation: The inner layer is made of TPR (thermoplastic rubber), a modified thermoplastic polymer elastomer. This TPR material is usually obtained by blending and modifying elastomers with thermoplastic plastics, including but not limited to ethylene-propylene copolymer (EPM or EPDM), metallocene-olefin polymer (POE), ethylene-vinyl acetate copolymer (EVA), etc., with thermoplastic plastics to form a thermoplastic rubber.

[0033] The "sea-island" structure of thermoplastic rubber (TPR) provides the material with excellent resilience, achieving wear resistance and fulfilling the functional requirements of wear resistance and corrosion resistance for desulfurization slurry conveying pipelines.

[0034] The performance indicators of the TPR material used in this invention (including but not limited to the following data) are as follows:

[0035] 2. The barrier layer of the TPR steel-plastic composite pipe for desulfurization slurry transportation is formed by extrusion of thermoplastic polymer or modified barrier material. The materials used include, but are not limited to, EVOH, PVDC and other high-performance barrier polymer materials, which slow down the slow penetration of desulfurization slurry in the inner core pipe and reduce the possibility of corrosion to the steel pipe.

[0036] 3. The hot melt adhesive (e.g.) + epoxy resin layer of the TPR steel-plastic composite pipe for desulfurization slurry transportation, the hot melt adhesive on the outer layer of the inner core composite pipe and the epoxy resin sprayed inside the steel pipe are bonded together to form an organic whole, ensuring that the inner core pipe does not fall off the steel pipe.

[0037] 4. The steel pipes used in TPR steel-plastic composite pipes include welded steel pipes and seamless steel pipes. They are primarily designed to meet the high pressure and long span bending strength requirements for slurry transportation in steel-plastic composite pipes.

[0038] 5. TPR steel-plastic composite pipe for conveying desulfurization slurry in thermal power plants, with the outer layer material being weather-resistant polymer or other modified composite materials (including but not limited to weather-resistant epoxy resin, modified PP / PE, etc.).

[0039] Manufacturing process of TPR steel-plastic composite pipe for conveying desulfurization slurry in thermal power plants

[0040] 1. Selection of raw materials, extrusion molds and production equipment requirements for inner core composite pipes

[0041] 1) Compatibility and fusion of raw materials for the inner core composite pipe

[0042] The inner core composite tube is co-extruded from TPR wear-resistant material, barrier polymer material, and hot melt adhesive. All three materials are primarily vinyl polymers, exhibiting good compatibility and allowing for blending in any proportion. The inner core composite tube is formed in one step using a co-extrusion molding die.

[0043] The epoxy resin sprayed on the inner layer of the steel pipe has good adhesion to both the steel material and the inner core composite pipe, firmly bonding the inner core composite pipe to the steel pipe without it falling off.

[0044] The outer layer of TPR steel-plastic composite pipe can be made of one or more materials (such as weather-resistant epoxy resin or other modified materials), one or more layers.

[0045] 2) Composite extrusion production line equipment and extrusion die

[0046] The inner core of the TPR composite pipe is produced by a three-layer co-extrusion pipe production line and a composite co-extrusion mold.

[0047] The inner wall of the inner core composite tube has three spiral diversion reinforcing ribs to divert flow, reduce noise, and improve the span bending strength and ring stiffness of the tube, resisting the possibility of the inner core composite tube being flattened due to vacuum. The width of the reinforcing rib is 3.0-8.0mm and the height is 1.5-5.0mm. The die design for extruding the reinforcing rib is shown in the figure below.

[0048] 3) Rotary traction

[0049] The three spiral reinforcing ribs on the inner wall of the inner core composite tube must be achieved through rotational traction.

[0050] The extrusion speed of the inner core composite tube must match the rotational speed of the rotary traction system; that is, the linear velocity / rotational speed ratio must be within a certain range, generally 0.5–2 m / s. This is to achieve the correct spiral spacing of the reinforcing ribs on the inner wall of the composite tube, specifically determined by the tube diameter and the required twist angle. If the ratio is too large, the spiral spacing will be too large, failing to achieve the purpose of flow diversion and noise reduction; if the ratio is too small, the spiral spacing will also be too small, potentially affecting the flow rate of the pipeline. Furthermore, due to excessive rotation speed, the composite tube is prone to twisting and breakage. The rotational speed of the rotary traction system is 0.5–5 rpm.

[0051] 2. Preparation of raw materials

[0052] All raw materials must be kept dry with a moisture content of no more than 0.2%; polymer materials can be dried at a temperature of 80-85℃ for 4 hours; steel pipes must be dried on both the inner and outer surfaces and must be derusted.

[0053] 3. Preparation of the inner core composite tube

[0054] 1) Place the three types of inner core tube raw materials into three extruders respectively, and control the extrusion temperature, screw speed and extrusion speed respectively, so that the three fully plasticized melts are compounded and formed in the composite co-extrusion die, and finally extruded into a tube blank with internal reinforcing ribs through the die.

[0055] The processing temperature of the inner TPR material is 160-180℃; the processing temperature of the middle barrier material is 190-210℃; and the processing temperature of the outer hot melt adhesive is 210-220℃.

[0056] 2) The extruded inner core composite tube blank is twisted by rotational traction, vacuum-shaped and cooled. The extrusion speed and the rotational speed of traction are adjusted and controlled, i.e. the value of extrusion line speed / rotational speed, which is generally 0.5-2 meters / revolution. According to the tube diameter and the required twist angle, the inner wall reinforcing ribs of the tube are twisted into spiral flow-dividing reinforcing ribs to form an inner core composite tube with spiral flow-dividing reinforcing ribs.

[0057] 4. Surface treatment of flanged steel pipes

[0058] 1) Rust removal treatment of steel pipe surface

[0059] The rust and oxide layer on the inner and outer surfaces of the steel pipe are removed by physical rust removal methods before use.

[0060] 2) Apply epoxy resin or protective material to both inner and outer surfaces.

[0061] After rust removal, the steel pipe is coated with epoxy resin or protective material on both the inner and outer layers, making the bond between the main steel pipe and the inner core composite pipe stronger and more reliable.

[0062] 5. Composite core pipe with steel pipe

[0063] 1) Tensile penetration

[0064] By using a stretching device, the inner core composite tube is stretched appropriately and its diameter is reduced, which facilitates the stretching of the inner core composite tube into the steel pipe.

[0065] 2) Heating and bonding followed by cooling and shaping

[0066] The inner core tube, inserted into the steel pipe, is sealed at both ends and pressurized air is injected to maintain a pressure of 0.4–0.6 MPa. The medium-frequency heating device is turned on and moved along the steel pipe, with the heating efficiency and moving speed carefully controlled. The temperature is controlled at 180–200℃ and the moving speed is 0.3–0.6 m / min (note the relationship between the medium-frequency heating efficiency and the moving speed; if the inner core tube is too cold or too hot, it will not achieve good adhesion to the steel pipe). After the inner core composite tube softens and the hot melt adhesive on the outer surface fully adheres to the epoxy resin layer on the inner surface of the steel pipe, cooling water is sprayed in time to cool and solidify the inner core composite tube, thus completing the good adhesion between the inner core composite tube and the steel pipe. The adhesion strength between the inner core composite tube and the steel pipe is ≥100 N / cm.

[0067] 6. Connection structure of TPR steel-plastic composite pipe

[0068] The connection structure of the steel-plastic composite pipe is formed by the inner core composite pipe being flanged on the flange, creating a closed loop of organic polymer channel. This ensures that the slurry inside the pipe does not come into contact with the steel material, thus achieving the purpose of wear resistance and corrosion prevention for the steel-plastic composite pipe.

[0069] After testing, inner core tubes of appropriate length were cut from both ends of the steel pipe, and the ends of the composite pipe were heated and plasticized at a temperature of 140-160℃. The temperature and pressure were controlled, and the plasticized composite pipe was folded onto the flanges at both ends using a folding device to achieve sealing and corrosion protection at the steel pipe connection.

[0070] Example 1: Preparation of DN50 TPR steel-plastic composite pipe

[0071] First, a φ50 inner core composite pipe is prepared, with an inner TPR material thickness of 1.8mm, an intermediate barrier layer thickness of 1.5mm, and an outer hot melt adhesive thickness of 0.5mm; the reinforcing rib width is 5.0mm and the height is 3.0mm; the traction line speed / rotation speed is 0.8m / revolution, producing a TPR material inner core composite pipe with spiral reinforcing ribs, whose ring stiffness is 1.4 times that of a pipe of the same ordinary shape; the inner and outer surfaces of the DN50 steel pipe are treated with rust removal, and epoxy resin is sprayed on them; then the TPR material inner core composite pipe and the pre-treated DN50 steel pipe are bonded and composited through heating and cooling; the two ends of the inner core composite pipe are flanged to form a corrosion-resistant polymer material fluid channel to achieve the purpose of corrosion protection; the pipeline is connected using polymer material flanged connections.

[0072] This TPR steel-plastic composite pipe is used in desulfurization slurry conveying systems. The solid content of the desulfurization slurry in thermal power plants is 18% (by mass), the flow rate is 2.5-2.6 m / s, and the wear of the inner TP new material mortar is 0.092% (SH / T1818-2017).

[0073] Example 2: Preparation of DN100 TPR steel-plastic composite pipe

[0074] First, a φ100 inner core composite pipe is prepared, with an inner TPR material thickness of 2.2mm, an intermediate barrier layer thickness of 2.0mm, and an outer hot melt adhesive thickness of 0.4mm. The reinforcing ribs are 5.5mm wide and 3.2mm high. The traction line speed / rotation speed is 1.3m / rotation, producing a TPR material inner core composite pipe with spiral reinforcing ribs, whose ring stiffness is 1.3 times that of a pipe of the same ordinary shape. The DN100 steel pipe undergoes rust removal treatment on both the inner and outer surfaces, and is simultaneously sprayed with epoxy resin. Then, the TPR material inner core composite pipe is bonded and composited with the pre-treated DN100 steel pipe through heating and cooling processes. The two ends of the inner core composite pipe are flanged to form a corrosion-resistant polymer material fluid channel to achieve the purpose of corrosion protection. The pipeline is connected using polymer material flanged connections.

[0075] This TPR steel-plastic composite pipe is used in desulfurization slurry conveying systems. The solid content of the desulfurization slurry in thermal power plants is 21% (by mass), the flow rate is 2.0-2.2 m / s, and the wear of the inner TP new material mortar is 0.11% (SH / T1818-2017).

[0076] Example 3: Preparation of DN200 TPR steel-plastic composite pipe

[0077] First, a φ200 inner core composite pipe is prepared, with an inner TPR material thickness of 3.0mm, an intermediate barrier layer thickness of 2.8mm, and an outer hot melt adhesive thickness of 0.6mm. The reinforcing ribs are 6.0mm wide and 3.5mm high. The traction line speed / rotation speed is 1.8m / rotation, producing a TPR material inner core composite pipe with spiral reinforcing ribs, whose ring stiffness is 1.2 times that of a pipe of the same ordinary shape. The DN200 steel pipe undergoes rust removal treatment on both the inner and outer surfaces, and is simultaneously sprayed with epoxy resin. Then, the TPR material inner core composite pipe is bonded and composited with the pre-treated DN200 steel pipe through heating and cooling processes. The two ends of the inner core composite pipe are flanged to form a fluid channel for the anti-corrosion polymer material, achieving the purpose of corrosion protection. The pipeline is connected using polymer material flanged connections.

[0078] This TPR steel-plastic composite pipe is used in desulfurization slurry conveying systems. The solid content of the desulfurization slurry in thermal power plants is 25% (by mass), the flow rate is 1.6-1.7 m / s, and the wear of the inner TP new material mortar is 0.12% (SH / T1818-2017).

Claims

1. A TPR steel-plastic composite pipe for conveying desulfurization slurry in a thermal power plant, characterized in that, From the inside out, it includes a composite inner core tube and a steel pipe. The composite inner core tube has a three-layer structure. The inner layer of the composite inner core tube is a TPR wear-resistant layer (1), the outer layer is a composite inner core tube middle layer, the middle layer is a polymer barrier layer (2), and the outer layer is a hot melt adhesive layer (3). The inner wall of the steel pipe (5) is provided with an epoxy resin layer (4). The steel pipe (5) is sleeved on the outside of the composite inner core tube. The composite inner core tube and the steel pipe are bonded together by the hot melt adhesive layer (3) and the epoxy resin layer (4). The outer side of the steel pipe is sprayed with a weather-resistant protective layer (6). The inner surface of the TPR wear-resistant layer (1) is provided with a spiral diversion reinforcing rib (7).

2. The TPR steel-plastic composite pipe for conveying desulfurization slurry in a thermal power plant according to claim 1, characterized in that, The spiral flow divider (7) consists of three parallel spiral ribs that spiral along the inner wall of the composite inner core tube.

3. The TPR steel-plastic composite pipe for conveying desulfurization slurry in a thermal power plant according to claim 1, characterized in that, At the end of the TPR steel-plastic composite pipe, the composite inner core pipe is longer than the steel pipe (5). The composite inner core pipe is turned outward by heating and turning it onto the flanges at both ends of the steel pipe for connection with the pipeline.

4. A TPR steel-plastic composite pipe for conveying desulfurization slurry in a thermal power plant according to claim 1, characterized in that, The TPR wear-resistant layer (1) is made of wear-resistant TPR material, and the thickness of the TPR wear-resistant layer (1) is 1.5-6.0 mm; A polymer barrier layer (2) with a thickness of 2.0–6.0 mm; The total thickness of the hot melt adhesive layer (3) and the epoxy resin layer (4) is 0.2-0.6 mm, which work together to... The inner core composite pipe is effectively bonded to the steel pipe to form a whole without falling off; The steel pipe (5) is a welded steel pipe or a seamless steel pipe with a diameter of DN40-DN1200mm, providing the pressure resistance and stiffness requirements for TPR steel-plastic composite pipe; The weather-resistant protective layer (6) is made of weather-resistant polymer or adhesive material and can be composed of one or more layers with a total thickness of 1.0-5.0 mm.

5. A TPR steel-plastic composite pipe for conveying desulfurization slurry in a thermal power plant according to claim 1, characterized in that, Spiral diversion reinforcing ribs (7) play a role in diverting flow and silencing in composite pipes, and strengthen the stiffness of the inner core composite pipe ring, thus improving the protection against the flattening and deformation of the inner core pipe under vacuum. The width of the reinforcing rib is 3.0-8.0 mm and the height is 1.5-5.0 mm. The material of the spiral diversion reinforcing rib (7) is the same as that of the TPR wear-resistant layer (1) and is integrated with the TPR wear-resistant layer (1).

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