Ascension pipe with independent inner cylinder, heat transfer method of ascension pipe and inner cylinder processing technology

Abstract

This invention relates to the field of coke oven waste heat recovery technology, specifically to a riser pipe with an independent inner cylinder, a heat transfer method for the riser pipe, and a processing technology for the inner cylinder. The invention comprises an outer shell, an inner cylinder, and a spiral coil arranged sequentially from the outside to the inside. The outer shell includes an outer shell body. The inner cylinder includes an inner wall and an outer wall, with their upper and lower ends connected by semi-ring pipe end caps. The spiral coil includes a spiral coil body, with a working fluid outlet pipe at the upper end and a working fluid outlet pipe flange at the other end. A working fluid inlet pipe is located at the lower end of the spiral coil body, with a working fluid inlet pipe flange at the other end. This invention employs an independent jacket structure, eliminating the technical problem of fatigue failure caused by thermal stress changes in the jacket angle connection structure, enhancing the heat transfer performance of the structure, and improving heat transfer efficiency and waste heat recovery efficiency under the same riser pipe height.

Description

Technical Field

[0001] This invention relates to the field of coke oven waste heat recovery technology, specifically to a riser pipe with an independent inner cylinder, a heat transfer method for the riser pipe, and a processing technology for the inner cylinder. Background Technology

[0002] Coking is a process of producing coke and by-product raw coal gas through the dry distillation of coking coal. It involves the primary energy processing of coking coal into coke, raw coal gas, and high-temperature heat energy conversion into secondary energy. Utilizing the waste heat resources generated during the coking process is one of the effective means to improve the energy efficiency of coke ovens. In particular, raw coal gas accounts for approximately 36% of the total heat energy expenditure of a coke oven. The utilization of high-quality waste heat at temperatures above 650℃ lays the technological and equipment foundation for the high-quality recovery and utilization of high-temperature waste heat from raw coal gas.

[0003] Currently, in practical applications within the coking industry, operators are concerned about water leakage from the heat exchange tubes entering the carbonization chamber. They require the heat exchange tubes to be placed inside a jacket to prevent water from entering the carbonization chamber immediately upon leakage, thus ensuring safe production. To address this, a jacketed coil technology for high-temperature waste heat recovery from raw coal gas has emerged. Its core principle involves installing a coil within a jacket formed between the riser pipe wall and the inner cylinder. A high thermal conductivity medium is added to the jacket outside the coil to increase the heat transfer coefficient, improve heat extraction, and enhance heat recovery efficiency.

[0004] Current problems with the technology:

[0005] ① The bottom flange of the jacket is connected to the inner cylinder at an angle. During the periodic process of the fire-fall curve in the coke oven production process, the temperature field changes periodically. The periodic temperature field will eventually form an alternating stress load on the structure. The periodic stress will lead to fatigue failure of the jacket structure. Raw coal gas enters the jacket, and the high-temperature sulfur in the raw coal gas will cause corrosion of the heat exchange coil, or even stress corrosion and dew point corrosion, thus accelerating the damage of the coil.

[0006] ② The heat transfer efficiency is low. Placing the heat exchange tube in the jacket, even though the jacket is filled with a heat transfer medium, the jacket structure still increases thermal resistance, reduces heat transfer, and affects the waste heat recovery efficiency.

[0007] ③ The coke oven riser pipe has a simple structure, which is not conducive to the recovery of waste heat from raw coal gas. Currently, the inner coil of the jacket is rolled outside the inner cylinder of the jacket. In particular, the heat transfer surface of the radiation heat transfer is the surface area of ​​the straight section of the cylinder, which does not realize the effective utilization of the heat exchange length of the riser pipe, loses the effective heat exchange area, and reduces the amount of waste heat recovery.

[0008] ④ When the temperature of raw coke oven gas drops to 450℃, coking and carbon deposition will occur. At present, all technologies aim to increase the thermal resistance to control the temperature of the heat exchange surface above 450℃. However, the thermal resistance still exists in the heat exchange process at high temperature, which reduces the heat transfer coefficient and the amount of waste heat recovery. Summary of the Invention

[0009] In view of the shortcomings of the prior art, the purpose of this invention is to provide a riser pipe with an independent inner cylinder, a heat transfer method for the riser pipe, and a processing technology for the inner cylinder, which can solve the above technical problems.

[0010] To achieve the above objectives, the present invention provides the following technical solution:

[0011] A riser pipe with an independent inner cylinder includes an outer shell, an inner cylinder, and a spiral coil arranged sequentially from the outside to the inside. The upper and lower ends of the outer shell and the inner cylinder are sealed with high-temperature resistant ceramic. An insulation layer is filled between the outer shell and the inner cylinder. The outer shell includes an outer shell body with an upper flange at the top and a lower flange at the bottom. A single-wave expansion joint is located in the middle section of the outer shell body. The inner cylinder includes an inner wall and an outer wall, both connected at their upper and lower ends by semi-circular pipe end caps. The inner wall of the inner cylinder uses an asymmetric spiral wave expansion joint, while the outer wall uses a cylindrical wall or an asymmetric spiral wave expansion joint. The inner cylinder has an expansion joint wall, with a vent pipe at the upper end and a connecting pipe at the lower end. The outer wall of the inner cylinder and the outer shell are welded and sealed together via the vent pipe at the upper end and the connecting pipe at the lower end, respectively. The spiral coil includes a spiral coil body, with a working fluid outlet connecting pipe at the upper end and a working fluid outlet connecting pipe flange at the outer end. The spiral coil body has a working fluid inlet connecting pipe at the lower end and a working fluid inlet connecting pipe flange at the outer end. The working fluid outlet connecting pipe is located inside the vent pipe, and the working fluid inlet connecting pipe is located inside the connecting pipe and a sealing plate is provided between them.

[0012] Preferably, the single-wave expansion joint is made of stainless steel with a wall thickness of ≤3mm; the inner cylinder is made of stainless steel; the spiral coil is made of carbon steel or high-temperature resistant alloy steel, and a close-packed structure with pre-tightening force is adopted between adjacent coil bodies.

[0013] Preferably, the inner diameter of the spiral wave expansion joint on the cylinder wall of the asymmetric spiral wave expansion joint matches the outer diameter of the spiral coil cylinder, and adjacent spiral wave expansion joints are connected by a spiral bellows.

[0014] Preferably, the inner diameter of the semi-annular tube end cap is equal to the outer diameter of the spiral coil cylinder.

[0015] Preferably, the axial dimension of the inner wall of the inner cylinder is closely matched with the axial dimension of the spiral coil body, and the radial dimension of the inner wall of the inner cylinder is a clearance fit with the radial dimension of the spiral coil body in the cold state and a tight fit in the hot state.

[0016] Preferably, the spiral coil body is composed of two or more coils connected together, and adjacent coils are connected by prefabricated integral pipe components.

[0017] Preferably, a high-temperature resistant ceramic anti-corrosion layer is provided on the inner wall of the outer shell and the outer surface of the outer wall of the inner cylinder; a high-conductivity medium, namely graphene, is provided between the inner wall of the inner cylinder and the spiral coil cylinder.

[0018] Preferably, an eccentric reducer is provided between the working fluid inlet pipe and the spiral coil body.

[0019] A heat transfer method for a riser pipe with an independent inner cylinder: During the operation of the riser pipe, the heat transfer coefficient changes suddenly due to the temperature change between the inner wall of the inner cylinder and the spiral coil body, resulting in enhanced heat transfer. The gap size of the gap fit under low-temperature operating conditions is ΔL=Δtλ(D2-D1), where ΔL is the gap size of the gap fit, Δt is the temperature difference between the lowest and highest operating temperatures of the inner wall of the inner cylinder, D1 and D2 are the inner diameter of the inner wall of the inner cylinder and the outer diameter of the spiral coil body, respectively, and λ1 and λ2 are the thermal expansion coefficients of the inner cylinder material and the spiral coil material, respectively.

[0020] A processing technology for an independent inner cylinder includes the following steps:

[0021] Step 1: Weld an inner wall and an outer wall of an inner cylinder using stainless steel plates. Roll or push the inner and outer walls of the inner cylinder into an asymmetric spiral wave expansion joint cylinder wall on a special forming machine. The outer wall of the inner cylinder can also be a cylindrical structure. Open a vent pipe port and a connecting pipe port at the upper and lower ends of the outer wall of the inner cylinder, respectively.

[0022] Step 2: Roll stainless steel pipes into ring pipes, weld them into ring pipes, and then perform stress-relieving annealing.

[0023] Step 3: Screw the inner wall of the inner cylinder into the spiral coil cylinder, and then fit the outer wall of the inner cylinder onto the outside of the spiral coil cylinder to form a jacket structure.

[0024] Step 4: Cut the stress-free ring pipe in half to form a semi-ring pipe end cap, and weld the semi-ring pipe end cap to the inner wall and outer wall of the inner cylinder to form an independent jacketed sealing cylinder.

[0025] Step 5: Perform a pressure test on the inner cylinder to ensure it is leak-proof.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1. The adoption of an independent jacket structure eliminates the technical problem of fatigue failure caused by thermal stress changes in the jacket corner connection structure, and essentially eliminates the safety hazard of fatigue failure of the jacket structure.

[0028] 2. The heat transfer performance of the structure has been enhanced, improving heat transfer efficiency and waste heat recovery efficiency under the same riser pipe height.

[0029] 3. The corrugated structure disrupts the boundary layer structure, increases the heat transfer coefficient of the hot fluid, and increases the amount of waste heat recovery.

[0030] 4. In this design, the inner wall of the cylinder is the main heat transfer surface. Raw coal gas begins to coke and deposit carbon at 450℃. The actual design requires a temperature higher than 450℃. If controlled at 480 or 500℃, the main heat transfer surface of the inner cylinder wall separates from the heat exchange coil, forming a gap filled with air. This causes the heat transfer coefficient to decrease in an "on-off" manner, lowering the heat transfer coefficient at the raw coal gas condensation point. In other words, at low temperatures, heat absorption and transfer cease. When the raw coal gas temperature exceeds the control temperature (e.g., controlled at 480 or 500℃), the expansion of the inner cylinder wall increases, and the inner... The main heat transfer surface of the inner wall of the cylinder contacts the heat exchange coil, forming a tight fit. After the main heat transfer surface of the inner wall of the inner cylinder is tightly fitted with the heat exchange coil, the gap filled with air is expelled. The inner wall of the inner cylinder and the heat exchange coil form an integral whole, and the heat transfer coefficient increases in an "on / off" manner. This improves the heat transfer coefficient at the condensation point of the raw coal gas. That is, under high temperature conditions, heat absorption and heat transfer are enhanced, and the heat exchange efficiency increases in an "on / off" manner. This eliminates the phenomenon of coking and carbon deposition that occurs when the raw coal gas in the coke oven drops to 450℃. This "on / off" structure is an automatic structure control of the heat transfer performance of the raw coal gas.

[0031] 5. The corrugated structure is characterized by a long fatigue life, which can reach more than 16,000 cycles, completely eliminating the problem of short fatigue life of existing jacket structures and achieving an inherently improved safety performance with an overall life of more than 10 years for the waste heat recovery riser.

[0032] 6. The independent inner cylinder structure ensures that water leakage from the heat exchange spiral tube will not enter the coke oven carbonization chamber, thus enhancing heat exchange and heat extraction while better protecting the safety of the coke oven. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0034] Figure 1 This is a schematic diagram of the structure of the present invention;

[0035] Figure 2 This is a schematic diagram of the spiral coil structure of the present invention;

[0036] Figure 3 This is a schematic diagram of the inner cylinder structure of the present invention. Figure 1 ;

[0037] Figure 4 This is a schematic diagram of the inner cylinder structure of the present invention. Figure 2 .

[0038] Explanation of reference numerals in the attached figures:

[0039] 1-Outer shell, 11-Outer shell body, 12-Upper flange, 13-Lower flange, 14-Single-wave expansion joint, 2-Inner cylinder, 21-Inner cylinder inner wall, 22-Inner cylinder outer wall, 23-Semi-ring pipe end cap, 24-Vent pipe, 25-Connecting pipe, 3-Spiral coil, 31-Spiral coil body, 32-Working fluid outlet connecting pipe, 33-Working fluid outlet connecting pipe flange, 34-Working fluid inlet connecting pipe, 35-Working fluid inlet connecting pipe flange, 36-Eccentric reducer, 4-High temperature resistant ceramic, 5-Insulation layer. Implementation

[0040] The invention will now be described in detail with reference to the accompanying drawings, by way of example. Obviously, the described embodiments are only some embodiments of the invention, and not all embodiments. Example 1

[0041] like Figures 1 to 3 As shown, this invention provides a riser pipe with an independent inner cylinder, comprising an outer shell 1, an inner cylinder 2, and a spiral coil 3 arranged sequentially from the outside to the inside. The upper and lower ends of the outer shell 1 and the inner cylinder 2 are sealed with high-temperature resistant ceramic 4, and a heat insulation layer 5 is filled between the outer shell 1 and the inner cylinder 2. The independent inner cylinder 2 structure eliminates the technical problem of fatigue failure caused by thermal stress changes in the jacketed corner connection structure.

[0042] Furthermore, in this embodiment, the outer shell 1 includes an outer shell cylinder 11, the top of the outer shell cylinder 11 is provided with an upper flange 12, the bottom is provided with a lower flange 13, and a single-wave expansion joint 14 is welded to the middle section of the outer shell cylinder 11.

[0043] Furthermore, in this embodiment, the inner cylinder 2 includes an inner wall 21 and an outer wall 22. The upper and lower ends of the inner wall 21 and the outer wall 22 are connected by semi-ring pipe end caps 23. The inner wall 21 adopts an asymmetric spiral wave expansion joint cylinder wall, and the outer wall 22 adopts a cylindrical cylinder wall. The upper end of the outer wall 22 is provided with a vent pipe 24, and the lower end is provided with a connecting pipe 25. The outer wall 22 and the outer shell 11 are welded and sealed together via the upper vent pipe 24 and the lower connecting pipe 25, respectively. The inner wall 21 adopts a corrugated structure, which increases the heat transfer coefficient of the hot fluid and the amount of waste heat recovery. Simultaneously, the corrugated structure has a long fatigue life, reaching over 16,000 cycles, completely eliminating the problem of short fatigue life in existing jacket structures and achieving an inherently improved safety performance with an overall lifespan of over 10 years for the waste heat recovery riser pipe. The independent inner cylinder 2 structure ensures that water leakage from the heat exchange spiral tube will not enter the coke oven carbonization chamber, thus enhancing the heat exchange and heat extraction of the waste heat recovery riser while better protecting the safety of the coke oven.

[0044] Furthermore, in this embodiment, the spiral coil 3 includes a spiral coil body 31, the upper end of the spiral coil body 31 is provided with a working fluid outlet pipe 32, the outer end of the working fluid outlet pipe 32 is provided with a working fluid outlet pipe flange 33, the lower end of the spiral coil body 31 is provided with a working fluid inlet pipe 34, and the outer end of the working fluid inlet pipe 34 is provided with a working fluid inlet pipe flange 35.

[0045] Furthermore, in this embodiment, the working fluid outlet pipe 32 is installed inside the vent pipe 24, and the working fluid inlet pipe 34 is installed inside the pipe 25 and a sealing plate is provided between them. By setting the sealing plate, it is beneficial to allow water leakage from the spiral coil 3.

[0046] Furthermore, in this embodiment, the single-wave expansion joint 14 is made of stainless steel with a wall thickness ≤3mm, preferably 2mm; the inner cylinder 2 is made of stainless steel; the spiral coil 3 is made of carbon steel or high-temperature alloy steel, and a close-packed structure with pre-tightening force is adopted between adjacent coil bodies, with the tubes tightly fitted together, which makes full use of the heat exchange area of ​​the riser tube, achieves high heat exchange efficiency, enhances the heat transfer performance of the structure, and improves the heat transfer efficiency under the same riser tube height, while also improving the waste heat recovery efficiency.

[0047] Furthermore, in this embodiment, the inner diameter of the spiral wave expansion joint on the wall of the asymmetric spiral wave expansion joint matches the outer diameter of the spiral coil cylinder 31, and adjacent spiral wave expansion joints are connected by a spiral bellows.

[0048] Furthermore, in this embodiment, the inner diameter of the semi-annular end cap 23 is equal to the outer diameter of the spiral coil body 31.

[0049] Furthermore, in this embodiment, the axial dimension of the inner wall 21 of the inner cylinder is closely matched with the axial dimension of the spiral coil body 31, and the radial dimension of the inner wall 21 of the inner cylinder and the radial dimension of the spiral coil body 31 are in a clearance fit in the cold state and a tight fit in the hot state.

[0050] Furthermore, in this embodiment, the spiral coil body 31 can be a single coil or a combination of two or more coils connected together, with adjacent coils connected by prefabricated integral pipe components.

[0051] Furthermore, in this embodiment, a high-temperature resistant ceramic anti-corrosion layer is provided on the inner wall of the outer shell 11 and the outer surface of the inner cylinder outer wall 22; a high-conductivity medium, namely graphene, is provided between the inner cylinder inner wall 21 and the spiral coil cylinder 31 to achieve the purpose of enhancing heat transfer.

[0052] Furthermore, in this embodiment, an eccentric reducer 36 is provided between the working fluid inlet pipe 34 and the spiral coil body 31. The function of the eccentric reducer 36 is to control the water inflow or steam outflow, thereby automating the riser system. The working fluid is water or steam. When producing saturated steam, the smaller end of the reducer is connected to a small-diameter pipe as the water inlet pipe and its matching flange; when producing superheated steam, the smaller end of the reducer is connected to a large-diameter pipe as the steam outlet pipe and its matching flange, with the upper opening of the coil serving as the steam inlet pipe.

[0053] In this invention, the inner wall 21 of the inner cylinder is the main heat transfer surface. Raw coal gas begins to coke and deposit carbon at 450℃, but the actual design requires a temperature higher than 450℃. If controlled at 480 or 500℃, the main heat transfer surface of the inner wall 21 separates from the heat exchange coil, forming a gap filled with air. This causes the heat transfer coefficient to decrease in an "on-off" manner, lowering the heat transfer coefficient at the condensation point of the raw coal gas. In other words, heat absorption and transfer cease at low temperatures. When the raw coal gas temperature exceeds the controlled temperature (e.g., controlled at 480 or 500℃), the expansion of the inner wall 21 of the inner cylinder increases, and the inner cylinder... The main heat transfer surface of the inner wall 21 contacts the heat exchange coil, forming a tight fit. After the main heat transfer surface of the inner wall 21 of the inner cylinder is tightly fitted with the heat exchange coil, the gap filled with air is expelled. The inner wall 21 of the inner cylinder and the heat exchange coil form an integral whole, and the heat transfer coefficient increases in an "on / off" manner. This improves the heat transfer coefficient at the condensation point of the raw coal gas. That is, under high temperature conditions, heat absorption and heat transfer are enhanced, and the heat exchange efficiency increases in an "on / off" manner. This eliminates the phenomenon of coking and carbon deposition that occurs when the raw coal gas in the coke oven drops to 450℃. This "on / off" structure is an automatic structure control of the heat transfer performance of the raw coal gas. Example 2

[0054] like Figure 4As shown, it is the same as in Embodiment 1, except that the outer wall 22 of the inner cylinder also adopts an asymmetric spiral waveform expansion joint cylinder wall. The advantage of this structure is that the inner cylinder 2 has low stress, making it easier to internalize the stress of the components and generate no additional stress.

[0055] Heat transfer method of riser with independent inner cylinder: During the operation of the riser, the heat transfer coefficient of the gap fit and tight fit is suddenly changed by the temperature change between the inner wall 21 of the inner cylinder and the spiral coil body 31, thus forming enhanced heat transfer; the gap of the gap fit, the gap size under low temperature working conditions is ΔL=Δtλ(D2-D1), where ΔL is the gap size of the gap fit, Δt is the temperature difference between the lowest and highest working temperatures of the inner wall 21 of the inner cylinder, D1 and D2 are the inner diameter of the center of the inner wall 21 of the inner cylinder and the outer diameter of the center of the spiral coil body 31, respectively, and λ1 and λ2 are the thermal expansion coefficients of the inner cylinder material and the spiral coil material, respectively.

[0056] A processing technology for an independent inner cylinder includes the following steps:

[0057] Step 1: Weld an inner cylinder inner wall 21 and an inner cylinder outer wall 22 using stainless steel plates. Roll or push the inner cylinder inner wall 21 and the inner cylinder outer wall 22 into an asymmetric spiral wave expansion joint cylinder wall on a special forming machine. The inner cylinder outer wall 22 can also be directly adopted as a cylindrical structure. Vent pipe 24 and pipe 25 are opened at the upper and lower ends of the inner cylinder outer wall 22, respectively.

[0058] Step 2: Roll stainless steel pipes into ring pipes, weld them into ring pipes, and then perform stress-relieving annealing.

[0059] Step 3: Screw the inner wall 21 of the inner cylinder into the spiral coil body 31, and then fit the outer wall 22 of the inner cylinder onto the outside of the spiral coil body 31 to form a jacket structure.

[0060] Step 4: Cut the stress-free ring pipe in half to form a semi-ring pipe end cap 23, and weld the semi-ring pipe end cap 23 to the inner wall 21 and the outer wall 22 of the inner cylinder to form an independent jacketed sealing cylinder.

[0061] Step 5: Perform a pressure test on the inner cylinder 2 to ensure it is leak-proof.

[0062] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and application concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A riser pipe with an independent inner cylinder, comprising an outer shell (1), an inner cylinder (2), and a spiral coil (3) arranged sequentially from the outside to the inside, wherein the upper and lower ends of the outer shell (1) and the inner cylinder (2) are sealed by high-temperature resistant ceramic (4), and a heat insulation layer (5) is filled between the outer shell (1) and the inner cylinder (2), characterized in that, The outer shell (1) includes an outer shell cylinder (11), the top of the outer shell cylinder (11) is provided with an upper flange (12), the bottom is provided with a lower flange (13), and the middle section of the outer shell cylinder (11) is provided with a single-wave expansion joint (14). The inner cylinder (2) includes an inner wall (21) and an outer wall (22). The upper and lower ends of the inner wall (21) and the outer wall (22) are connected by a semi-ring pipe end cap (23). The inner wall (21) is an asymmetric spiral wave expansion joint cylinder wall. The outer wall (22) is a cylindrical cylinder wall or an asymmetric spiral wave expansion joint cylinder wall. The upper end of the outer wall (22) is provided with a vent pipe (24), and the lower end is provided with a connecting pipe (25). The outer wall (22) and the outer shell cylinder (11) are respectively welded and sealed by the vent pipe (24) at the upper end and the connecting pipe (25) at the lower end. The spiral coil (3) includes a spiral coil body (31), the upper end of the spiral coil body (31) is provided with a working fluid outlet pipe (32), the outer end of the working fluid outlet pipe (32) is provided with a working fluid outlet pipe flange (33), the lower end of the spiral coil body (31) is provided with a working fluid inlet pipe (34), and the outer end of the working fluid inlet pipe (34) is provided with a working fluid inlet pipe flange (35). The working fluid outlet pipe (32) is installed inside the vent pipe (24), and the working fluid inlet pipe (34) is installed inside the pipe (25); The inner diameter of the spiral wave expansion joint on the wall of the asymmetric spiral wave expansion joint matches the outer diameter of the spiral coil cylinder (31), and adjacent spiral wave expansion joints are connected by a spiral bellows. A sealing plate is provided between the working fluid inlet pipe (34) and the pipe (25), and an eccentric reducer (36) is provided between the working fluid inlet pipe (34) and the spiral coil body (31).

2. The riser pipe with an independent inner cylinder as described in claim 1, characterized in that, The single-wave expansion joint (14) is made of stainless steel with a wall thickness of ≤3mm; the inner cylinder (2) is made of stainless steel; the spiral coil (3) is made of carbon steel or high-temperature alloy steel, and the adjacent two coil bodies adopt a close-packed structure with pre-tightening force.

3. The riser pipe with an independent inner cylinder as described in claim 1, characterized in that, The inner diameter of the semi-circular end cap (23) is equal to the outer diameter of the spiral coil body (31).

4. The riser pipe with an independent inner cylinder as described in claim 1, characterized in that, The axial dimension of the inner wall (21) of the inner cylinder is closely matched with the axial dimension of the spiral coil body (31). The radial dimension of the inner wall (21) of the inner cylinder and the radial dimension of the spiral coil body (31) are in a clearance fit in the cold state and a tight fit in the hot state.

5. The riser pipe with an independent inner cylinder as described in claim 1, characterized in that, The spiral coil body (31) is composed of two or more coils connected together, and adjacent coils are connected by prefabricated integral pipe components.

6. The riser pipe with an independent inner cylinder as described in claim 1, characterized in that, A high-temperature resistant ceramic anti-corrosion layer is provided on the inner wall of the outer shell (11) and the outer surface of the inner cylinder outer wall (22); a high-conductivity medium is provided between the inner wall (21) of the inner cylinder and the spiral coil cylinder (31), and the high-conductivity medium is graphene.

7. A heat transfer method for a riser pipe with an independent inner cylinder as described in any one of claims 1-6, characterized in that, During the operation of the riser pipe, the heat transfer coefficient of the gap fit and tight fit is suddenly changed by the temperature change between the inner wall (21) of the inner cylinder and the spiral coil cylinder (31), resulting in enhanced heat transfer.

8. A processing method for a riser pipe with an independent inner cylinder as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Weld an inner cylinder inner wall (21) and an inner cylinder outer wall (22) using stainless steel plates. Roll or push the inner cylinder inner wall (21) and the inner cylinder outer wall (22) into an asymmetric spiral wave expansion joint cylinder wall on a special forming machine. The inner cylinder outer wall (22) adopts a cylindrical structure. A vent pipe (24) and a connecting pipe (25) are opened at the upper and lower ends of the inner cylinder outer wall (22). Step 2: Roll stainless steel pipes into ring pipes, weld them into ring pipes, and then perform stress-relieving annealing. Step 3: Screw the inner wall (21) of the inner cylinder into the spiral coil cylinder (31), and then put the outer wall (22) of the inner cylinder onto the outside of the spiral coil cylinder (31) to form a jacket structure; Step 4: Cut the stress-free ring pipe in half to form a semi-ring pipe end cap (23), and weld the semi-ring pipe end cap (23) to the inner wall (21) and the outer wall (22) of the inner cylinder to form an independent jacketed sealing cylinder; Step 5: Perform a pressure test on the inner cylinder (2) to ensure it is leak-proof.

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