Lightweight high-temperature-resistant modification process for inlet and outlet pipe box manhole of hydrogen production reformer

Abstract

The invention relates to the technical field of modification of high-temperature parts of hydrogen production equipment, and discloses a lightweight high-temperature-resistant modification process for a manhole of an inlet and outlet channel of a hydrogen production reformer. According to the process, aluminum oxide continuous fibers serve as a core material, a composite structure plug with an inner layer (a sealing heat insulation layer), a middle layer (a structure reinforcing layer) and an outer layer (a protective wear-resistant layer) is designed and formed through material type selection and pretreatment, adaptive modification treatment is conducted on the flange face and the inner wall of a manhole body, and finally assembling and performance testing are completed. The manhole plug is obviously lightened, the weight is reduced by 70% or above, meanwhile, the manhole plug has excellent high temperature resistance (the long-term use temperature is larger than or equal to 1200 DEG C), high heat insulation (the heat conductivity coefficient is low), sealing stability and thermal shock resistance, and the problems that a traditional hard plug is large in weight, poor in performance and short in service life are solved. The operation safety, the heat efficiency and the maintenance convenience of the hydrogen production reformer can be greatly improved, the localization rate of materials is high, and the cost advantage is obvious.

Description

Technical Field

[0001] This invention relates to the field of high-temperature component modification technology for hydrogen production equipment, specifically to a lightweight, high-temperature resistant modification process for the manhole of the inlet and outlet pipe box of a hydrogen production converter. It is particularly suitable for using continuous alumina fiber as the core modification material to optimize the performance of manhole components under high temperature and high pressure conditions, and belongs to the field of key component manufacturing and modification technology for new energy equipment. Background Technology

[0002] The hydrogen production converter is the core equipment of a large-scale hydrogen production plant. Its inlet and outlet manholes serve as critical access points for equipment maintenance and repair, operating under harsh conditions of high temperature (800-1200℃), high pressure (1.0-3.0MPa), strong oxidation, and corrosive media. The manhole plug, as the core sealing and insulation component of the manhole, directly affects the operational safety, thermal efficiency, and service life of the hydrogen production converter.

[0003] (a) Deficiencies in existing technology

[0004] Currently, the plugs for the manholes of the inlet and outlet pipe boxes of hydrogen production converters are generally made of traditional hard materials (such as refractory bricks, corundum castables, silicon carbide-based composite materials, etc.). These materials have the following prominent problems:

[0005] 1. Heavy weight and inconvenient installation and maintenance: Traditional rigid plugs have a density of more than 4.0g / cm³, and a single plug can weigh 50-100kg. This means that the installation and disassembly process requires the use of lifting equipment, which is cumbersome, has low maintenance efficiency, and is prone to mechanical damage to pipe box flanges.

[0006] 2. Insufficient high-temperature resistance and poor thermal stability: Under the drastic temperature changes (500-1200℃) during the start-up and shutdown of the hydrogen production converter, traditional rigid materials have a large coefficient of thermal expansion (8-12×10⁻⁶). -6 (℃), poor thermal shock resistance, prone to cracking and peeling, leading to seal failure and increased risk of high-temperature media leakage.

[0007] 3. Limited heat insulation effect and serious energy loss: Traditional rigid materials have a high thermal conductivity (0.8-1.5W / (m·K) at room temperature), making it difficult to form an efficient heat insulation barrier. As a result, heat loss at the manhole of the tube box accounts for 15-20% of the total heat loss of the equipment, which significantly reduces the thermal efficiency of the hydrogen production converter.

[0008] 4. Poor sealing performance and short service life: The rigid material has poor fit with the pipe box flange and cannot adapt to the slight deformation of the flange surface. After long-term service, gaps are easily formed, leading to leakage of high-temperature flue gas. At the same time, the brittle nature of the material itself makes it easy to be damaged under vibration, impact and other working conditions. The service life is usually only 1-2 years, requiring frequent replacement and increasing the operating cost of the equipment.

[0009] (ii) Limitations of the application of existing fiber materials

[0010] To address the shortcomings of rigid materials, the industry has attempted to use soft materials such as ordinary ceramic fibers and glass fibers to fabricate manhole plugs, but the following technical bottlenecks remain:

[0011] 1. Insufficient high temperature resistance: The long-term operating temperature of ordinary ceramic fiber is mostly 800-1000℃. After exceeding 1000℃, the strength drops sharply and it is easy to pulverize; the long-term operating temperature of glass fiber is below 600℃, which cannot meet the high-temperature operating requirements of the inlet and outlet pipe boxes of the hydrogen production conversion furnace.

[0012] 2. Poor structural stability: Ordinary soft fiber materials have low tensile strength (single filament tensile strength <1000MPa) and insufficient elastic modulus (<80GPa). Under high pressure conditions, they are prone to compression deformation, which leads to an increase in sealing gap and makes it impossible to maintain a long-term stable sealing effect.

[0013] 3. Insufficient corrosion resistance and oxidation resistance: Under the high-temperature oxidizing atmosphere and trace acidic media (such as HCl and SO2) of the hydrogen production converter, ordinary fiber materials are prone to oxidative degradation or corrosion, resulting in material performance degradation and shortened service life.

[0014] (III) Technological Improvement Needs

[0015] As the hydrogen production industry develops towards larger scale, higher efficiency, and longer cycle operation, core requirements for manhole components in inlet and outlet pipe boxes have emerged: "lightweight, high temperature resistance, high thermal insulation, long lifespan, and easy maintenance." Therefore, there is an urgent need to develop a novel modification process that, through material innovation and structural optimization, addresses the technical deficiencies of traditional manhole plugs while overcoming the limitations of existing soft fiber materials, providing technical support for the safe and stable operation of hydrogen production converters. Summary of the Invention

[0016] The purpose of this invention is to address the problems of existing manhole plugs in hydrogen production converters, such as heavy weight, insufficient high-temperature resistance, poor insulation, weak sealing stability, and short service life, by providing a lightweight, high-temperature resistant modification process for the manholes in the inlet and outlet pipe boxes of hydrogen production converters. This process uses domestically produced continuous alumina fiber as the core material. Through optimized material selection, composite structure design, and precise process control, it achieves lightweight modification of the manhole components while significantly improving their high-temperature resistance, insulation, sealing, and structural stability, extending service life, reducing maintenance costs, and improving the operational safety and thermal efficiency of the hydrogen production converter.

[0017] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0018] A lightweight, high-temperature resistant modification process for the manhole of the inlet and outlet pipe box of a hydrogen production converter, characterized by comprising the following steps:

[0019] 1. Selection and pretreatment of modified material systems

[0020] (1) Selection of core materials

[0021] Alumina continuous fibers and their products produced by Shanghai Rongrong New Materials were selected as the core modifying materials. The material system includes:

[0022] Reinforcing layer material: M-99 type alumina continuous fiber woven fabric is selected. This material has an alumina content of ≥98%, the main crystalline phase is α-Al2O3, the tensile strength of a single filament is 2500MPa, the elastic modulus of a single filament is 310GPa, and the density is 3.8g / cm³. 3 With a long-term service temperature of 1200-1300℃, it possesses excellent high-temperature strength and structural stability; the woven fabric model selected is WF-800, with a width of 800mm, a warp and weft density of 12×8 threads / cm, a unit area mass of 800g / ㎡, a thickness of 0.85mm, and a plain weave structure to ensure structural density and tensile strength.

[0023] Insulation layer material: Alumina continuous fiber needled blanket (NT series) is selected. This material is made of alumina short fibers through physical needle punching, contains no organic components, has a long-term operating temperature of 1500℃, a maximum operating temperature of 1600℃, a thermal conductivity of ≤0.25W / (m·K) (at 1000℃), and a slag ball content of ≤1.0%. It has extremely low thermal conductivity and excellent thermal insulation performance. The needled blanket specifications are 400g / ㎡ and 0.40mm thick, ensuring a balance between lightweight and thermal insulation effect.

[0024] Sealing reinforcement material: SF-610 type alumina continuous fiber sewing thread is selected, with a diameter of 0.68mm, a linear density of 610Tex, a breaking strength of 140N, and a knot strength of 36N. It has high strength and high temperature resistance sewing performance and is used for fixing and sealing reinforcement of composite structures.

[0025] Functional coating material: Abrasion-resistant AR coating is selected. This coating has good compatibility with alumina continuous fibers. After coating, it can improve the wear resistance and resistance to media erosion of the material surface. The coating thickness is controlled at 0.1-0.2mm.

[0026] (2) Material pretreatment process

[0027] Pretreatment of woven fabric: The M-99 type WF-800 woven fabric is placed in a high-temperature furnace and pretreated at 800℃ for 2 hours with a heating rate of 5℃ / min. It is then naturally cooled to room temperature to remove residual stress inside the material and ensure that it does not shrink or deform under high-temperature conditions. The dimensional stability error of the woven fabric after pretreatment is ≤±0.5%.

[0028] Pretreatment of needled blanket: The alumina continuous fiber needled blanket is preheated at 600℃ for 1.5 hours with a heating rate of 8℃ / min. After cooling, a compression rebound test is performed to ensure that its compression rebound rate is ≥85% (when the compression amount is 20%), so as to avoid permanent deformation under high pressure conditions.

[0029] Sewing thread pretreatment: SF-610 sewing thread is subjected to heat stabilization treatment at 400℃ for 1 hour to remove surface impurities and improve its dimensional stability under high temperature environment. After treatment, the sewing thread retains ≥95% of its breaking strength.

[0030] 2. Composite structure design and molding of manhole plug

[0031] (1) Layered design of composite structure

[0032] The design adopts a "three-layer composite structure", which consists of the following layers from the inside out:

[0033] Inner layer (sealing and heat insulation layer): Alumina continuous fiber needled blanket is used, with a thickness of 20-30mm designed according to the manhole size. Through multi-layer stacking (5-8 layers), efficient heat insulation and flexible sealing are achieved. The fluffiness and resilience of the needled blanket are utilized to adapt to the slight deformation of the pipe box flange surface and ensure sealing fit.

[0034] Middle layer (structural reinforcement layer): M-99 type alumina continuous fiber woven fabric is wrapped around the outside of the inner needle-punched blanket. There are 2-3 layers. It is fixed by double-needle lockstitching process with SF-610 type sewing thread. The sewing density is 10-15 stitches / cm, forming a dense structural reinforcement layer, which improves the overall tensile and compressive strength of the end cap and prevents the inner needle-punched blanket from collapsing under high pressure conditions.

[0035] Outer layer (protective wear-resistant layer): AR wear-resistant coating is applied to the surface of the middle woven fabric. The coating thickness is 0.15mm. It is applied evenly by spraying with a spraying pressure of 0.3-0.5MPa and a spraying distance of 20-30cm to ensure that the coating is tightly bonded to the woven fabric. This improves the wear resistance and resistance to media erosion of the plug surface and avoids material damage during installation and disassembly.

[0036] (2) Control of molding process parameters

[0037] Cutting process: Based on the inner diameter of the manhole of the inlet and outlet pipe box of the hydrogen production converter (usually 500-800mm) and the flange structure, a CNC cutting machine is used to precisely cut the pre-treated woven fabric and needle-punched blanket. The cutting size error is ≤±1mm to ensure that the composite structure is accurately adapted to the human body size.

[0038] Layering and sewing process: The cut needle-punched blankets are layered according to the design number of layers and fixed with positioning fixtures to ensure that the number of layers is uniform and the thickness is consistent; then the woven fabric is wrapped around the outside of the needle-punched blankets, and the edges are aligned and then sewn to fix it. The sewing stitch is a continuous lockstitch with a stitch width of 3-5mm to ensure that the composite structure is not loose or delaminated.

[0039] Coating curing process: The composite structure coated with AR coating is placed in a 120℃ oven for pre-curing for 2 hours, and then the temperature is raised to 300℃ for final curing for 3 hours. The curing temperature rise rate is 3℃ / min. It is then naturally cooled to room temperature to ensure that the coating is completely cured and the adhesion to the woven fabric is ≥1.5MPa (cross-cut test).

[0040] 3. Adaptation and modification treatment of the manhole body

[0041] (1) Treatment of manhole flange sealing surface

[0042] The sealing surfaces of the manhole flanges of the inlet and outlet pipe boxes of the hydrogen production converter are sandblasted. The sandblasting medium is alumina sand (particle size 20-40 mesh), the sandblasting pressure is 0.6-0.8MPa, and the sandblasting distance is 15-20cm. After treatment, the surface roughness Ra=3.2-6.3μm, removing oxide scale, oil and impurities from the sealing surface and improving the fit and sealing performance with the modified plug.

[0043] (2) Thermal insulation modification of manhole inner wall

[0044] A layer of high-temperature resistant adhesive (temperature resistance ≥1200℃) is coated on the inner wall of the manhole, with a coating thickness of 0.5-1.0mm. Then, a thin layer of alumina continuous fiber electronic cloth (WF-100 type, thickness 0.12mm, surface density 105g / ㎡) is pasted on. This electronic cloth has good electrical insulation, is lightweight and has high tensile strength. It can form an auxiliary heat insulation layer to reduce heat loss of the manhole body and at the same time avoid oxidation and corrosion of the manhole body by high temperature.

[0045] 4. Assembly and debugging process

[0046] (1) End cap installation process

[0047] Slowly insert the formed composite plug into the manhole, ensuring that the plug fits tightly against the flange sealing surface without any offset or gaps. Tighten it with stainless steel bolts (high temperature resistance grade ≥1200℃), with the tightening torque controlled at 30-50 N·m to avoid excessive torque causing excessive compression of the plug or insufficient torque causing poor sealing.

[0048] (2) Sealing and high temperature resistance test

[0049] Leakage test: Using the airtightness test method, compressed air (1.2 times the working pressure) is introduced into the pipe box and pressurized for 30 minutes. The manhole area is then checked for leaks using the soap solution application method. The leakage rate is required to be ≤1×10⁻⁶. -6 Pa·m³ / s.

[0050] High temperature resistance test: The assembled manhole components are placed in a high temperature test furnace to simulate the operating conditions of a hydrogen production conversion furnace. The temperature is raised to 1200℃ and held for 1000 hours. After cooling, the dimensional change rate of the plug (required to be ≤1.0%), sealing performance and structural integrity are tested to ensure that there are no cracks, delamination or powdering.

[0051] The lightweight, high-temperature resistant modification process for the manhole of the hydrogen production converter inlet and outlet pipe box of the present invention, through material innovation, structural optimization and precise process control, has the following significant advantages compared with the prior art:

[0052] 1. Significant weight reduction and convenient installation and maintenance: The alumina continuous fiber material used in this invention has a density of only 3.8g / cm³ (M-99 type), and the overall density of the composite structure plug is ≤1.2g / cm³. Compared with traditional rigid plugs (density 4.0-5.0g / cm³), the weight is reduced by 70-80%, and the weight of a single plug can be controlled at 10-15kg. It can be manually installed and disassembled without lifting equipment, improving maintenance efficiency by more than 60%, and avoiding mechanical damage to pipe box flanges.

[0053] 2. Excellent high-temperature resistance and strong thermal stability: The core material, continuous alumina fiber, can withstand long-term service temperatures of 1200-1300℃, and the needle-punched blanket has a maximum service temperature of 1600℃, far exceeding the operating temperature of the inlet and outlet pipe boxes of the hydrogen production converter (800-1200℃); the material's coefficient of thermal expansion is only 3.5×10⁻⁶. -6 It exhibits excellent thermal shock resistance at 1000℃, and after 50 cycles of repeated cycles from 1200℃ to room temperature, there is no cracking or peeling. Its thermal stability is significantly better than that of traditional hard materials.

[0054] 3. Significantly improved thermal insulation efficiency and reduced energy loss: The thermal conductivity of the inner needle-punched blanket in the composite structure is ≤0.25W / (m·K) (at 1000℃). Combined with the synergistic thermal insulation effect of the middle woven fabric and the outer coating, the heat loss at the manhole is reduced by more than 80%, and the thermal efficiency of the hydrogen production converter is increased by 3-5%. Based on a single 10 million Nm³ / h hydrogen production unit, approximately 1.2 million Nm³ of natural gas can be saved annually, significantly reducing operating costs.

[0055] 4. Stable sealing performance and extended service life: The inner needle-punched blanket of the composite structure has good bulkiness and resilience (compression rebound rate ≥85%), which can tightly fit the flange sealing surface, adapt to minor deformation of the flange surface, and the sealing leakage rate is ≤1×10 -6 Pa·m³ / s, far superior to traditional rigid plugs (leakage rate ≥1×10⁻⁶). -4 (Pa·m³ / s); At the same time, the material has stable chemical properties, is resistant to oxidation and corrosion, and after long-term service at 1200℃, the performance degradation rate is ≤5%, and the service life is extended to 5-8 years. Compared with traditional plugs (1-2 years), the replacement frequency is reduced by 75%, significantly reducing maintenance costs and downtime.

[0056] 5. High localization rate of materials and obvious cost-effectiveness advantage: The alumina continuous fiber and its products selected in this invention are all independently developed and produced by Shanghai Rongrong New Materials, breaking the foreign technology monopoly. The localization rate of materials is 100%, and the cost is reduced by 40-50% compared with imported similar fiber materials. At the same time, the process does not require complex special equipment, which can realize large-scale production and has good prospects for industrial application.

[0057] 6. Reasonable structural design and strong adaptability: The composite structure design of this invention can be flexibly adjusted according to the manholes (inner diameter 500-800mm) of the inlet and outlet pipe boxes of hydrogen production converters of different specifications. By cutting, adjusting the number of stacked layers, etc., it can be adapted to manhole components of different sizes and pressure levels, with strong adaptability and wide applicability. Attached Figure Description

[0058] Figure 1 : A schematic diagram of the cross-sectional structure of the modified manhole plug of the present invention;

[0059] Figure 2 : A layered schematic diagram of the composite structure of the present invention;

[0060] Figure 3 : Flowchart of the modification process of this invention;

[0061] Figure 4 Schematic diagram of a test apparatus for comparing the performance of modified plugs and traditional plugs.

[0062] The markings in the diagram are as follows: 1. Manhole body; 2. Flange sealing surface; 3. Outer protective wear-resistant layer (AR coating); 4. Middle structural reinforcement layer (alumina continuous fiber woven fabric); 5. Inner sealing and heat insulation layer (alumina continuous fiber needle-punched blanket); 6. Stainless steel fastening bolts; 7. Auxiliary heat insulation layer (alumina continuous fiber electronic cloth); 8. High-temperature resistant adhesive layer. Detailed Implementation

[0063] The technical solution of the present invention will be described in detail below with reference to specific embodiments. In this embodiment, the inlet and outlet manhole of a 10 million Nm³ / h hydrogen production conversion furnace (inner diameter 600 mm, working temperature 1100℃, working pressure 2.0 MPa) is used as the modification object to explain the implementation process and effects of the present invention in detail.

[0064] (I) Example 1: Implementation of lightweight and high-temperature resistant modification process for manholes in inlet and outlet pipe boxes of hydrogen production converter

[0065] 1. Material preparation and pretreatment

[0066] (1) List of materials

[0067] Core reinforcing material: M-99 type alumina continuous fiber woven fabric (WF-800 model), 800mm width, warp and weft density 12×8 threads / cm, unit area mass 800g / ㎡, thickness 0.85mm, purchased from Shanghai Rongrong New Materials, its performance parameters are as follows: alumina content 99.2%, single filament diameter 12.0μm, single filament tensile strength 2550MPa, single filament elastic modulus 315GPa, density 3.8g / cm³, long-term service temperature 1250℃.

[0068] Thermal insulation material: Alumina continuous fiber needled blanket (NT-400 model), surface density 400g / ㎡, thickness 0.40mm, purchased from Shanghai Rongrong New Materials. Performance parameters: alumina content 98.5%, fiber diameter 7-14μm, long-term operating temperature 1500℃, maximum operating temperature 1600℃, thermal conductivity 0.22W / (m·K) (at 1000℃), slag ball content 0.8%, compression resilience 88% (at 20% compression).

[0069] Sealing reinforcement material: SF-610 type alumina continuous fiber sewing thread, diameter 0.68mm, linear density 610Tex, breaking strength 142N, knot strength 37N, purchased from Shanghai Rongrong New Materials.

[0070] Functional coating material: AR wear-resistant coating, high temperature resistance 1300℃, adhesion ≥1.6MPa, purchased from a supporting supplier of Shanghai Rongrong New Materials.

[0071] Auxiliary materials: high-temperature resistant adhesive (temperature resistance 1200℃), stainless steel bolts (temperature resistance grade 1200℃), alumina sand (particle size 30 mesh).

[0072] (2) Material pretreatment

[0073] Woven fabric pretreatment: Cut the WF-800 woven fabric into circular pieces with a diameter of 700mm (3 pieces in total), place them in a box-type high-temperature furnace, keep them at 800℃ for 2 hours, with a heating rate of 5℃ / min, and let them cool naturally to room temperature. After pretreatment, the diameter of the woven fabric was measured to be 699.7mm, and the dimensional stability error was 0.04%, which meets the design requirements.

[0074] Pretreatment of needle-punched blanket: Cut the NT-400 needle-punched blanket into circular pieces with a diameter of 700mm (6 pieces in total), place them in a high-temperature furnace, keep them at 600℃ for 1.5 hours, with a heating rate of 8℃ / min, and after cooling, conduct a compression rebound test. The rebound rate is 89% when the compression is 20%, which meets the requirements.

[0075] Sewing thread pretreatment: SF-610 sewing thread was placed in an oven and kept at 400℃ for 1 hour. After cooling, the breaking strength was tested and found to be 139N with a retention rate of 97.9%, which meets the requirements.

[0076] 2. Composite structure molding

[0077] (1) Layered assembly

[0078] Inner sealing and heat insulation layer: Six pre-treated needled blankets are stacked sequentially and fixed with positioning fixtures to ensure that the thickness after stacking is 24mm (0.40mm×6 pieces), the overall diameter after stacking is 699.8mm, the thickness is uniform, and there are no obvious wrinkles.

[0079] Middle layer reinforcement layer: Three pre-treated woven fabrics are wrapped around the outside of the inner needle-punched blanket in sequence, aligning the edges to ensure that the woven fabrics completely cover the needle-punched blanket with no exposed parts.

[0080] Sewing and fixing: SF-610 sewing thread is used to fix the middle layer of woven fabric and the inner layer of needle-punched blanket with double-needle lockstitch. The sewing density is 12 stitches / cm, the stitch width is 4mm, the sewing path is circular, and a total of 3 sewing threads are set from the inside to the outside with a spacing of 50mm to ensure that the composite structure is not loose or delaminated.

[0081] (2) Coating application and curing

[0082] Coating application: Using an air spraying device, the AR wear-resistant coating is evenly applied to the surface of the middle layer woven fabric. The spraying pressure is 0.4MPa, the spraying distance is 25cm, and two coats are applied. Each coat is 0.075mm thick, and the total coating thickness is 0.15mm. After coating, ensure that there are no drips or bubbles.

[0083] Curing treatment: The coated composite structure was placed in an oven and pre-cured at 120℃ for 2 hours, then heated to 300℃ for final curing for 3 hours at a heating rate of 3℃ / min. After natural cooling to room temperature, the coating adhesion was tested and found to be 1.7MPa (cross-cut test), which met the requirements.

[0084] 3. Manhole Body Adaptation Modification

[0085] (1) Flange sealing surface treatment

[0086] A sandblasting device was used to sandblast the sealing surface of the manhole flange with alumina sand (30 mesh) as the medium. The sandblasting pressure was 0.7 MPa, the sandblasting distance was 18 cm, and the sandblasting time was 3 minutes. After treatment, the surface roughness Ra=4.8 μm, removing the surface oxide scale and oil stains, and the cleanliness met the requirements.

[0087] (2) Thermal insulation modification of manhole inner wall

[0088] A high-temperature resistant adhesive was evenly applied to the inner wall of the manhole using a brush, with a coating thickness of 0.8 mm. Then, a cut WF-100 type alumina continuous fiber electronic cloth (thickness 0.12 mm, surface density 105 g / ㎡) was pasted onto the surface of the adhesive layer and compacted with a pressure roller to ensure that the electronic cloth was tightly adhered to the inner wall without bubbles or wrinkles, forming an auxiliary heat insulation layer.

[0089] 4. Assembly and debugging

[0090] (1) Installation of plug

[0091] The formed composite plug (diameter 699.8mm, thickness 24.15mm) is slowly inserted into the manhole. The position is adjusted to ensure that the plug fits tightly against the flange sealing surface without any deviation. Twelve stainless steel bolts are evenly distributed around the flange circumference and tightened in a symmetrical order, with the tightening torque controlled at 40 N·m.

[0092] (2) Performance testing

[0093] Leakage test: Compressed air is introduced into the pipe box, and the pressure is increased to 2.4 MPa (1.2 times the working pressure). The pressure is maintained for 30 minutes. Soap solution is applied to the manhole area. If no bubbles are generated, the leakage rate is 8 × 10⁻⁶. -7 Pa·m³ / s, which meets the sealing requirements.

[0094] High-temperature resistance test: The assembled manhole components were placed in a high-temperature test furnace, heated to 1100℃, and held at that temperature for 1000 hours. After cooling, the plug dimensions were checked: diameter 699.3mm, thickness 24.0mm, dimensional change rate 0.07%, with no cracking, delamination, or powdering. A sealing test was then conducted, with a leakage rate of 9×10⁻⁶.-7 Pa·m³ / s, with stable sealing performance.

[0095] Lightweight test: The modified plug weighs 12.5kg, which is 80.8% lighter than the traditional rigid plug (65kg). Installation can be completed by 2 people without the need for lifting equipment, significantly improving maintenance efficiency.

[0096] Thermal insulation performance test: At an operating temperature of 1100℃, the outer surface temperature of the manhole was measured to be 85℃, which is 61.4% lower than the outer surface temperature of the traditional plug (220℃), reducing heat loss by 82% and improving the thermal efficiency of the hydrogen production conversion furnace by 4.2%.

[0097] (II) Example 2: Performance Comparison Test of Different Material Combinations

[0098] To verify the rationality of the material selection in this invention, a comparative experiment was conducted. Endcaps were prepared using different fiber materials, modified according to the process in Example 1, and their various properties were tested. The results are shown in the table below:

[0099] experimental group core materials Long-term operating temperature (°C) Plug weight (kg) Leakage rate (Pa·m³ / s) Dimensional change rate (%) after 1000 hours of high temperature External surface temperature (°C) Estimated service life (years) This invention group M-99 type alumina continuous fiber 1250 12.5 <![CDATA[8×10 -7 ]]> 0.07 85 7.5 Comparison Group 1 Ordinary ceramic fiber 1000 14.2 <![CDATA[5×10 -5 ]]> 1.8 156 2.0 Comparison Group 2 Fiberglass 600 13.8 <![CDATA[2×10 -4 ]]> 3.2 189 1.0 Comparison Group 3 Imported alumina fiber 1200 13.1 <![CDATA[7×10 -7 ]]> 0.09 88 7.0 Traditional Group Corundum Castable 1100 65.0 <![CDATA[3×10 -4 ]]> 2.5 220 1.5

[0100] As shown in the table above, the M-99 type continuous alumina fiber from Shanghai Rongrong New Materials Co., Ltd. in this invention group is superior to ordinary ceramic fiber, glass fiber and traditional corundum castable in terms of high temperature resistance, lightweight effect, sealing performance, heat insulation performance and service life. Compared with imported alumina fiber, the performance is comparable, but the material cost is reduced by 45%, which has a significant cost-performance advantage.

[0101] (III) Example 3: Process Parameter Optimization Experiment

[0102] To verify the rationality of the process parameters of this invention, orthogonal experiments were conducted on three key parameters: woven fabric pretreatment temperature, number of needle-punched blanket layers, and coating thickness. The dimensional stability, sealing performance, and thermal insulation performance of the plug were used as evaluation indicators. The experimental results are as follows:

[0103] Test number Pretreatment temperature of woven fabric (°C) Number of layers of needle-punched blanket Coating thickness (mm) Dimensional change rate (%) Leakage rate (Pa·m³ / s) External surface temperature (°C) Overall score 1 600 4 0.10 0.35 <![CDATA[3×10 -6 ]]> 102 75 2 600 6 0.15 0.12 <![CDATA[1×10 -6 ]]> 90 88 3 600 8 0.20 0.08 <![CDATA[9×10 -7 ]]> 86 92 4 800 4 0.15 0.10 <![CDATA[8×10 -7 ]]> 92 90 5 800 6 0.20 0.05 <![CDATA[7×10 -7 ]]> 84 96 6 800 8 0.10 0.07 <![CDATA[9×10 -7 ]]> 88 93 7 1000 4 0.20 0.09 <![CDATA[8×10 -7 ]]> 89 91 8 1000 6 0.10 0.08 <![CDATA[1×10 -6 ]]> 93 89 9 1000 8 0.15 0.06 <![CDATA[7×10 -7 ]]> 85 94

[0104] Note: The overall score is weighted by the dimensional change rate (30%), leakage rate (30%), and external surface temperature (40%). The higher the score, the better the performance.

[0105] The orthogonal experiment results show that the highest comprehensive score (96 points) is achieved when the woven fabric pretreatment temperature is 800℃, the number of needle-punched blanket layers is 6, and the coating thickness is 0.20mm. At this temperature, the dimensional change rate of the plug is 0.05%, and the leakage rate is 7×10⁻⁶. -7With Pa·m³ / s and an external surface temperature of 84℃, the performance is optimal, representing the optimal combination of process parameters for this invention. This is consistent with the process parameters used in Example 1, verifying the rationality and optimization of the process parameters of this invention.

[0106] (iv) Example 4: Long-term operational stability test

[0107] The modified manhole plug from Example 1 was installed on a 10 million Nm³ / h hydrogen production converter and subjected to a two-year long-term operation test. Performance indicators were periodically monitored, and the results are as follows:

[0108] Running time (months) External surface temperature (°C) Leakage rate (Pa·m³ / s) Appearance of the plug 0 85 <![CDATA[8×10 -7 ]]> No cracks, no delamination, coating intact 6 87 <![CDATA[9×10 -7 ]]> No cracks, no delamination, coating intact 12 89 <![CDATA[1×10 -6 ]]> No cracks, no delamination, only minor localized wear on the coating. 18 92 <![CDATA[1.2×10 -6 ]]> No cracks, no delamination, and coating wear area ≤ 5%. 24 95 <![CDATA[1.5×10 -6 ]]> No cracks, no delamination, and coating wear area ≤8%.

[0109] Long-term operation tests show that the modified manhole plug maintained a stable external surface temperature of 85-95℃ and a leakage rate of ≤1.5×10⁻⁶ during two years of operation. -6 Pa·m³ / s, with no cracking, delamination, or powdering, minimal coating wear, and stable performance. The estimated service life is 7-8 years, significantly better than the 1-2 years of traditional plugs, verifying the long-term stability and reliability of the modified process of this invention.

[0110] In summary, the lightweight and high-temperature resistant modification process for the inlet and outlet manholes of the hydrogen production converter of this invention, through material innovation, structural optimization, and precise process control, effectively solves the technical defects of traditional manhole plugs, such as large weight, insufficient high-temperature resistance, poor heat insulation, weak sealing stability, and short service life. It has significant technical advantages and economic value, and can be widely used in the modification of manhole components in various hydrogen production converters and other high-temperature equipment, which has important significance for promotion and application.

[0111] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A lightweight, high-temperature resistant modification process for the manhole of the inlet and outlet pipe box of a hydrogen production converter, characterized in that: Includes the following steps: S1. Selection and pretreatment of modified materials: Select a material system with alumina continuous fiber as the core and pretreat each material. S2, Manhole plug composite structure forming: Based on the three-layer composite structure design of "inner sealing and heat insulation layer (5) - middle structural reinforcement layer (4) - outer protective wear-resistant layer (3)", the pre-treated material is processed into shape through cutting, stacking, sewing and coating processes; S3. Manhole body adaptation modification: The flange sealing surface (2) of the manhole body (1) is roughened, and an auxiliary heat insulation layer (7,8) is laid on the inner wall of the manhole. S4. Assembly and performance verification: Install the molded plug into the adapted modified manhole, tighten it with the specified torque using the fastening bolt (6), and perform sealing and high temperature resistance tests.

2. The lightweight, high-temperature resistant modification process for the manhole of the inlet and outlet pipe box of a hydrogen production converter according to claim 1, characterized in that: In step S1, the material system includes: The alumina continuous fiber woven fabric used as the reinforcing layer material has an alumina content of ≥98% and a single filament tensile strength of ≥2500MPa. Alumina continuous fiber needled blanket, used as a heat insulation layer material, has a long-term service temperature ≥1500℃; Alumina continuous fiber sewing thread as a sewing fixing material; And wear-resistant high-temperature coatings as surface protection materials.

3. The lightweight, high-temperature resistant modification process for the manhole of the inlet and outlet pipe box of a hydrogen production converter according to claim 2, characterized in that: The alumina continuous fiber needled blanket has a thermal conductivity of ≤0.25W / (m·K) at 1000℃ and a compression resilience of ≥85% at 20% compression.

4. The lightweight, high-temperature resistant modification process for the manhole of the inlet and outlet pipe box of a hydrogen production converter according to claim 1, characterized in that: In step S1, the pretreatment includes: subjecting the alumina continuous fiber woven fabric to high-temperature stabilization treatment at 750-850°C; The alumina continuous fiber needled blanket is preheated and shaped at 550-650℃.

5. The lightweight, high-temperature resistant modification process for the manhole of the inlet and outlet pipe box of a hydrogen production converter according to claim 1, characterized in that: In step S2, the inner sealing and heat insulation layer (5) is composed of multiple layers of the alumina continuous fiber needle-punched blanket, with a total thickness of 20-30mm; the middle structural reinforcement layer (4) is wrapped with at least one layer of the alumina continuous fiber woven fabric on the outer side of the inner layer and fixed by sewing with the sewing thread at a density of 10-15 stitches / cm.

6. The lightweight, high-temperature resistant modification process for the manhole of the inlet and outlet pipe box of a hydrogen production converter according to claim 5, characterized in that: In step S2, the outer protective wear-resistant layer (3) is formed by spraying the wear-resistant high-temperature coating onto the surface of the middle structural reinforcement layer (4), with a coating thickness of 0.1-0.2 mm, and is treated by a stepped temperature curing process.

7. The lightweight, high-temperature resistant modification process for the manhole of the inlet and outlet pipe box of a hydrogen production converter according to claim 1, characterized in that: In step S3, the roughening treatment of the manhole flange sealing surface (2) is sandblasting, and the medium used is alumina sand with a particle size of 20-40 mesh. After the treatment, the surface roughness Ra is 3.2-6.3μm.

8. The lightweight, high-temperature resistant modification process for the manhole of the inlet and outlet pipe box of a hydrogen production converter according to claim 1, characterized in that: In step S3, the auxiliary heat insulation layer consists of a high-temperature resistant adhesive layer (8) coated on the inner wall of the manhole and an alumina continuous fiber electronic cloth (7) pasted thereon.

9. The lightweight, high-temperature resistant modification process for the manhole of the inlet and outlet pipe box of a hydrogen production converter according to claim 1, characterized in that: In step S4, the tightening torque for installing the plug is controlled between 30-50 N·m; the sealing test requires that after applying and maintaining a pressure of 1.2 times the working pressure inside the manhole, the leakage rate should be ≤1×10⁻⁶. -6 Pa·m³ / s.

10. The lightweight, high-temperature resistant modification process for the manhole of the inlet and outlet pipe box of a hydrogen production converter according to claim 1, characterized in that: In step S4, the high temperature resistance test is performed by keeping the assembled parts at 1200℃ for 1000 hours, and the dimensional change rate of the plug is ≤1.0%, with no cracking or delamination.

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