A method for producing a flue castable for reducing gas corrosion in a fluidized bed boiler

Abstract

The present application relates to the technical field of flue castable, in particular to a preparation method of flue castable for reducing gas corrosion in fluidized bed boiler, comprising: S1, mixing powder ingredients, S2, preparing splicing layer, S3, preparing reinforcing material, S4, preparing anti-corrosion flue castable; the present application adopts splicing layer, which significantly improves the corrosion resistance of flue castable, especially the ability to resist gas corrosion, improves the mechanical strength and impact resistance of the material; after pouring the reinforcing material and airing, the surface layer material is poured, the three materials are used in combination, and the corrosion-resistant flue cast layer with strong comprehensive quality is obtained; the strength and wear resistance of the cast layer are further improved by pouring the reinforcing material; the long-acting protective layer with high-temperature resistance, acid medium resistance and chemical smoke corrosion resistance is formed by the surface layer material.

Description

Technical Field

[0001] This invention relates to the field of flue gas refractory technology, specifically to a method for preparing flue gas refractory that reduces gas corrosion in fluidized bed boilers. Background Technology

[0002] In modern industrial production, fluidized bed boilers are widely used in power, chemical, and metallurgical industries due to their high efficiency and environmental friendliness. However, during operation, acidic gases (such as SOx and NOx) in the flue gas can cause severe corrosion to the internal metal components, affecting the equipment's lifespan and operational safety. To address this issue, the traditional approach is to use refractory castables for protection inside the boiler.

[0003] While traditional refractory castables can resist the erosion of high-temperature flue gas to a certain extent, their acid resistance is not ideal, especially when exposed to environments containing acidic gases for a long time, their corrosion resistance will gradually decrease. Traditional castables are prone to cracking under rapid temperature changes, leading to material spalling and damage, thereby reducing the service life of boilers. The construction process of traditional castables is complex, requiring professional technicians and has a long construction period, affecting the progress and cost of projects. Traditional castables exhibit significant performance differences under different working environments, making it difficult to meet the needs of various complex working conditions. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method for preparing flue gas casting material that reduces gas corrosion in fluidized bed boilers.

[0005] The technical solution of this invention is: a method for preparing flue gas casting material to reduce gas corrosion in fluidized bed boilers, comprising the following steps:

[0006] S1, Mixed Powder Ingredients

[0007] By mass percentage, 12-14% barium sulfate powder, 10-12% microsilica powder, 3-8% alloy fiber, 1-8% zinc oxide powder, 3-5% γ-alumina powder, and the balance aluminum chromium slag powder are mixed evenly to obtain a mixed powder.

[0008] S2, Prepare the splicing layer

[0009] Measure the dimensions of the flue to be poured, select several sheet-like molds matching its dimensions, the mold thickness being 0.5–3 cm, introduce mixed powder into the molds, press and shape, keep at 1000–1800℃ for 0.5–1 h, after cooling, lay a layer of polytetrafluoroethylene (PTFE) film on its surface, then lay a layer of basalt fiber cloth or aramid fiber cloth on the PTFE film, then lay another layer of PTFE film, and finally evenly lay a layer of mesh galvanized steel wire, keep at 90–110℃ for 12–24 h, cool and demold to obtain the spliced ​​layer; the thickness of the two PTFE films is 0.08–0.3 mm, the thickness of the basalt fiber cloth or aramid fiber cloth is 0.4–0.5 mm, and the average thickness of the mesh galvanized steel wire is 0.5–2.5 mm;

[0010] S3, Preparation of reinforcing material

[0011] By weight percentage, 15-25% titanium carbide powder, 15-18% biochar powder, 10-15% perlite, 2-15% fused magnesia powder, 8-14% glass microspheres, 5-10% polyacrylic acid microspheres, 2-7% polyvinyl alcohol, 2-5% sodium polyacrylate, and the balance cement are mixed with an appropriate amount of water at 90-110°C to obtain the reinforcing material.

[0012] S4. Preparation of anti-corrosion flue casting material

[0013] S4-1, Pre-treatment of glass flakes;

[0014] S4-2, Preparation of surface material;

[0015] S4-3. Adjust the viscosity of the surface material, splice the splicing layer onto the inner wall of the flue, then pour the reinforcing material, and finally pour the surface material. By combining the raw materials according to the above operations, a flue casting material that reduces gas corrosion can be obtained.

[0016] Instructions: When using this product, measure the flue dimensions, prepare several splicing layers, place the splicing layers inside the flue, pour in the reinforcing material, let it dry, and then pour in the surface material. The three materials are used in combination to pour the flue.

[0017] Zinc oxide in the mixed powder can react with other components such as γ-alumina and fused magnesia powder at high temperatures to form refractory minerals, thereby improving the refractory properties of the castable. Zinc oxide has good light stability and antioxidant properties, which can improve the weather resistance of the castable. The addition of zinc oxide may help reduce the shrinkage of the castable during the cooling process, thereby reducing the formation of cracks. Zinc oxide can improve the corrosion resistance of the castable, especially in acidic environments.

[0018] Polytetrafluoroethylene (PTFE) film acts as an insulator between galvanized steel wire and basalt fiber cloth or aramid fiber cloth, absorbing and dispersing stress caused by temperature changes and preventing direct transfer to the basalt fiber cloth or aramid fiber cloth, thus protecting the anti-corrosion layer and reducing damage. During the high-temperature melting and thermoplasticization process, the materials of each layer fuse together at high temperature to form a tightly bonded integral structure. This process helps to improve the overall strength and sealing of the anti-corrosion layer, making it more resistant to the effects of temperature changes. The smooth surface of PTFE film has an extremely low coefficient of friction, which helps to reduce friction between materials, thereby reducing the risk of damage and detachment caused by friction. PTFE film can maintain its physical and chemical properties over a wide temperature range, which means that it can be used in high and low temperature environments without losing its anti-corrosion performance.

[0019] Further, the barium sulfate powder in S1 has a particle size of 50-60 μm, the microsilica powder has a particle size of 30-40 μm, the alloy fiber has an average length of 1-3 mm, the zinc oxide powder has a particle size of 20-40 μm, the γ-alumina powder has a particle size of 20-30 μm, and the aluminum chromium slag powder has a particle size of 0.2-5 mm.

[0020] Explanation: Particles of different sizes can better fill spaces, forming a dense packing and improving the material's density and overall performance; smaller particles can fill the gaps between larger particles, increasing contact points and improving the material's density and strength; mixing particles of different sizes can increase the contact area between particles, helping to improve the interfacial bonding force between components, thereby enhancing the material's mechanical properties and corrosion resistance; optimizing particle size distribution can improve the material's durability and service life, which is especially important for materials like flue gas duct castables that need to operate in harsh environments for extended periods.

[0021] Further, the method for pretreating glass flakes described in S4-1 is as follows: clean the glass flake raw materials with acetone of 95-98% by mass or alcohol of 99-99.9% by mass, polish the surface of the glass flakes, dry them, and then perform acid washing.

[0022] Instructions: Clean the glass flake raw materials with acetone (95-98% by mass) or alcohol (99-99.9% by mass) to remove surface oil, dust, and other contaminants. Grind the glass flake surface to remove rough parts and uneven edges, improving its smoothness. After cleaning and treatment, the glass flakes need to be dried to remove surface moisture and prevent the introduction of moisture during subsequent mixing and construction, which would lead to performance degradation. Remove the oxide layer and other inorganic impurities from the glass flake surface by acid washing.

[0023] Furthermore, the glass flakes have particle sizes of 20 mesh, 60 mesh, and 110 mesh, with mass ratios of 9 to 10:1:1, respectively.

[0024] Note: Glass flakes of different sizes can form a multi-layered, interwoven structure in the coating, effectively blocking the penetration of corrosive media and improving the coating's corrosion resistance. Appropriate glass flake particle size and proportion can enhance the coating's adhesion and toughness, reducing the risk of cracking and peeling. As a surface layer, when subjected to friction, damage to the glass flake coating is limited to a localized area and does not affect the overall wear resistance of the coating. Glass flakes themselves have a low coefficient of thermal expansion, enabling them to adapt to high-temperature working environments and possessing excellent thermal shock resistance.

[0025] Further, the method for preparing the surface material described in S4-2 is as follows: by mass percentage, 50-60% of the glass flakes pretreated in S4-1, 1-3% of the curing agent, 1-3% of the accelerator, 1-2% of the thixotropic stabilizer, 1-12% of the low-shrinkage agent, 0.2-1.2% of the silane coupling agent, 0.2-1% of the defoamer, 0.1-3% of the nano-silica, and the balance of the vinyl ester resin are mixed evenly to obtain the surface material.

[0026] Note: The high proportion of glass flakes enhances the coating's corrosion and abrasion resistance, especially when exposed to strong acids, alkalis, or other corrosive media. Curing agents, accelerators, and thixotropic stabilizers help improve the coating's curing speed and application performance. The addition of low-shrinkage agents helps reduce volume shrinkage during curing, preventing stress and cracking caused by shrinkage and improving coating integrity and durability. The use of silane coupling agents improves the interfacial bonding between the glass flakes and the resin matrix, enhancing coating adhesion and durability. The addition of thixotropic stabilizers and defoamers helps improve the coating's rheological properties while reducing bubble formation. The addition of nano-silica improves the coating's weather resistance and UV radiation resistance, extending its service life.

[0027] Furthermore, the curing agent is 328E; the accelerator is an organotin compound or a tertiary amine compound; the thixotropic stabilizer is BYK-R605; the low-shrinkage agent is polyamide; the defoamer is BYK-555; and the silane coupling agent is propyltrimethoxysilane.

[0028] Note: 328E is an epoxy resin curing agent that reacts with vinyl ester resin to achieve rapid curing and shorten the production cycle. 328E has good compatibility with vinyl ester resin, which helps to form a uniform coating structure. Organotin compounds and tertiary amine compounds act as accelerators, which can accelerate the reaction rate between the curing agent and the resin and improve production efficiency. These accelerators help control the exothermic reaction during the curing process and avoid coating defects caused by overheating.

[0029] BYK-R605, as a highly efficient thixotropic stabilizer, improves the rheological properties of the coating while maintaining its shape in a static state, preventing sagging. The use of thixotropic stabilizers helps improve the ease of application and the uniformity of the coating. Polyamide, as a low-shrinkage agent, effectively reduces volume shrinkage during the coating curing process, avoiding internal stress and cracks caused by shrinkage. Reducing shrinkage helps improve the integrity and durability of the coating. BYK-555 is a highly efficient defoamer that effectively eliminates bubbles generated during mixing and application, improving the appearance and performance of the coating. The use of defoamers helps to obtain a smoother, defect-free coating surface.

[0030] Furthermore, the method for adjusting the viscosity of the surface material described in S4-3 is as follows: during the stirring process, an appropriate amount of diluent or thickener is added evenly to adjust the casting viscosity of the surface material to 0.5 to 1 Pa·s.

[0031] Note: Adjusting viscosity makes the surface coating easier to pour, improving construction convenience and efficiency. Appropriate viscosity helps form a uniform coating during pouring, avoiding poor flow due to excessive viscosity or sagging due to insufficient viscosity, thus ensuring coating quality and consistency. Viscosity adjustment indirectly controls the reaction rate and heat release during curing, helping to avoid coating defects caused by excessively fast or slow curing. Different construction environments and conditions require different viscosity settings. Adjusting viscosity allows the surface coating to adapt to different construction temperatures, humidity levels, and other environmental factors, improving the material's adaptability and flexibility. Viscosity adjustment also helps improve the physical and chemical properties of the coating, such as corrosion resistance, abrasion resistance, and weather resistance.

[0032] Furthermore, the diluent is one or any combination of methanol, ethanol, acetone, methyl ethyl ketone, butyl acetate, and ethyl acetate, and the thickener is one or a combination of fumed silica and bentonite.

[0033] Note: Solvents such as methanol, ethanol, acetone, methyl ethyl ketone, butyl acetate, and ethyl acetate have good solubility and volatility, making them suitable for various resin systems. They can effectively reduce viscosity, making the surface layer easier to pour. These diluents typically have a fast evaporation rate, which helps to dry quickly after application, reducing waiting time and improving application efficiency. Viscosity can be precisely adjusted by selecting a single diluent or a combination thereof to meet different application requirements.

[0034] Fumed silica is a highly efficient thickener that can increase viscosity without significantly altering the chemical properties of the resin system, providing good thixotropy and flow control. Bentonite is a natural mineral thickener with excellent thickening effect and suspension stability, which can improve the viscosity and stability of surface materials and prevent sedimentation and stratification. Fumed silica and bentonite can not only thicken but also improve the heat resistance and chemical resistance of the coating, enhancing the overall performance of the coating.

[0035] The beneficial effects of this invention are:

[0036] (1) By using materials such as barium sulfate powder, microsilica powder, zinc oxide powder, γ-alumina powder and aluminum chromium slag powder, this invention can significantly improve the corrosion resistance of flue casting materials, especially their ability to resist gas corrosion; the addition of alloy fibers can enhance the mechanical strength and impact resistance of the materials; when using this invention, several splicing layers are arranged inside the flue, a reinforcing material is poured, and after drying, a surface material is poured. The three materials are used in combination to obtain a flue casting layer with strong comprehensive quality and corrosion resistance; when preparing the splicing layer, the mixed powder is pressed into shape and kept warm for a long time, which helps to improve the structural stability and high temperature resistance of the materials; by preparing the splicing layer, it can be customized according to the actual size of the flue, which improves the flexibility and convenience of construction; the splicing layer is stabilized by the reinforcing material, and the corrosion resistance of the flue is enhanced by the surface material.

[0037] (2) This invention strengthens the strength of the castable by galvanized steel wire, making it easier to withstand the weight of the castable and the pressure during construction, while also having good durability to ensure its long-term use; hot-dip galvanizing improves its corrosion resistance; the mesh structure allows for a certain deformation space when heated or cooled, thereby compensating for expansion or contraction caused by temperature changes and reducing tensile or compressive stress on the anti-corrosion layer; after high-temperature thermoplasticization, the room temperature cooling process allows the anti-corrosion layer to gradually solidify and reach its final physical state; the components of the anti-corrosion layer will adapt to each other's size and shape to form a stable composite structure, thereby reducing internal stress and potential risk of peeling caused by temperature changes.

[0038] (3) The zinc oxide in the splicing layer of the present invention can react with the components in the cement in the reinforcing material to form a harder structure, thereby improving the mechanical strength of the castable; the combination of materials such as titanium carbide powder, biochar powder, perlite, and fused magnesia powder in the reinforcing material further improves the strength and wear resistance of the material; by using anti-corrosion mortar as a surface material, an easy-to-construct and long-lasting protective layer with high temperature resistance, acid resistance and chemical fume corrosion resistance can be prepared. Attached Figure Description

[0039] Figure 1 These are bar charts showing the compressive strength test results of samples from Examples 1-7, 12, and 13 of this invention, as well as Comparative Examples 1-4.

[0040] Figure 2 These are bar charts showing the linear changes in samples after burning in Examples 1-7, 12, and 13 of this invention, as well as Comparative Examples 1-4. Detailed Implementation

[0041] To further illustrate the methods and effects of this invention, the technical solution of this invention will be clearly and completely described below in conjunction with experiments.

[0042] Example 1:

[0043] A method for preparing flue gas castable refractory to reduce gas corrosion in fluidized bed boilers includes the following steps:

[0044] S1, Mixed Powder Ingredients

[0045] By weight percentage, 13% barium sulfate powder, 11% microsilica powder, 5.5% alloy fiber, 4.5% zinc oxide powder, 4% γ-alumina powder, and the balance aluminum chromium slag powder are mixed evenly to obtain a mixed powder.

[0046] The barium sulfate powder has a particle size of 54.5–55 μm, the microsilica powder has a particle size of 34.5–35 μm, the alloy fiber has an average length of 1.5–2 mm, the zinc oxide powder has a particle size of 29.5–30 μm, the γ-alumina powder has a particle size of 24.5–25 μm, and the aluminum chromium slag powder has a particle size of 2.5–2.6 mm.

[0047] S2, Prepare the splicing layer

[0048] Measure the dimensions of the flue to be poured, select several sheet-like molds matching its dimensions, the molds being 1.25cm thick, introduce mixed powder into the molds, press and shape them, keep them at 1400℃ for 0.75h, after cooling, lay a layer of polytetrafluoroethylene (PTFE) film on its surface, then lay a layer of basalt fiber cloth or aramid fiber cloth on the PTFE film, then lay another layer of PTFE film, and finally evenly lay a layer of mesh galvanized steel wire, keep it at 100℃ for 18h, cool and demold to obtain the spliced ​​layer; the thickness of the two PTFE films is 0.2mm, the thickness of the basalt fiber cloth or aramid fiber cloth is 0.45mm, and the average thickness of the mesh galvanized steel wire is 1.5mm;

[0049] S3, Preparation of reinforcing material

[0050] By weight percentage, 20% titanium carbide powder, 16.5% biochar powder, 12.5% ​​perlite, 8.5% fused magnesia powder, 11% glass microspheres, 7.5% polyacrylic acid microspheres, 4.5% polyvinyl alcohol, 3.5% sodium polyacrylate, and the balance cement are mixed with an appropriate amount of water at 100°C to obtain the reinforcing material.

[0051] S4. Preparation of anti-corrosion flue casting material

[0052] S4-1, Pre-treatment of glass flakes

[0053] The method for pretreating glass flakes is as follows: the glass flake raw material is cleaned with acetone with a mass concentration of 96.5%, the surface of the glass flakes is polished, dried, and then acid-washed; the particle size of the glass flakes includes 20 mesh, 60 mesh, and 110 mesh, with a mass ratio of 9.5:1:1 respectively.

[0054] S4-2, Preparation of surface material

[0055] The method for preparing the mixed raw materials is as follows: by mass percentage, 55% of glass flakes pretreated with S4-1, 2% of curing agent, 2% of accelerator, 1.5% of thixotropic stabilizer, 6.5% of low shrinkage agent, 0.7% of silane coupling agent, 0.6% of defoamer, 2% of nano silica, and the balance of vinyl ester resin are mixed evenly to obtain the surface material;

[0056] The curing agent is 328E; the accelerator is an organotin compound or a tertiary amine compound; the thixotropic stabilizer is BYK-R605; the low-shrinkage agent is polyamide; the defoamer is BYK-555; and the silane coupling agent is propyltrimethoxysilane.

[0057] S4-3, Adjust the viscosity of the surface material

[0058] The method for adjusting the viscosity of the surface material is as follows: during the stirring process, an appropriate amount of diluent or thickener is added evenly to adjust the casting viscosity of the surface material to 0.75 Pa·s; the diluent is methanol, and the thickener is bentonite. The splicing layer is laid inside the flue, and then the reinforcing material is poured. After drying, the surface material is poured. The materials are used in sequence to obtain the anti-corrosion flue casting material.

[0059] Example 2: This example is basically the same as Example 1, except that, by mass percentage, 12% barium sulfate powder, 10% microsilica powder, 3% alloy fiber, 1% zinc oxide powder, 3% γ-alumina powder and the balance aluminum chromium slag powder are mixed evenly to obtain a mixed powder.

[0060] Example 3: This example is basically the same as Example 1, except that, by mass percentage, 14% barium sulfate powder, 12% microsilica powder, 8% alloy fiber, 8% zinc oxide powder, 5% γ-alumina powder and the balance aluminum chromium slag powder are mixed evenly to obtain a mixed powder.

[0061] Example 4: This example is basically the same as Example 1, except that the mold thickness is 0.5cm. Mixed powder is introduced into the mold, pressed and shaped, kept at 1000℃ for 0.5h, and after cooling, a layer of polytetrafluoroethylene film is laid on its surface. Then, a layer of basalt fiber cloth or aramid fiber cloth is laid on the polytetrafluoroethylene film, followed by another layer of polytetrafluoroethylene film. Finally, a layer of mesh galvanized steel wire is evenly laid, kept at 90℃ for 12h, and after cooling, it is demolded to obtain the spliced ​​layer.

[0062] Example 5: This example is basically the same as Example 1, except that the mold thickness is 3cm. Mixed powder is introduced into the mold, pressed and shaped, kept at 1800℃ for 1 hour, and after cooling, a layer of polytetrafluoroethylene film is laid on its surface. Then, a layer of basalt fiber cloth or aramid fiber cloth is laid on the polytetrafluoroethylene film, followed by another layer of polytetrafluoroethylene film. Finally, a layer of mesh galvanized steel wire is evenly laid, kept at 110℃ for 24 hours, and after cooling, it is demolded to obtain the spliced ​​layer.

[0063] Example 6: This example is basically the same as Example 1, except that, by mass percentage, 15% titanium carbide powder, 15% biochar powder, 10% perlite, 2% fused magnesia powder, 8% glass microspheres, 5% polyacrylic acid microspheres, 2% polyvinyl alcohol, 2% sodium polyacrylate, and the balance cement are mixed evenly with an appropriate amount of water at 90°C to obtain the reinforcing material.

[0064] Example 7: This example is basically the same as Example 1, except that, by mass percentage, 25% titanium carbide powder, 18% biochar powder, 15% perlite, 15% fused magnesia powder, 14% glass microspheres, 10% polyacrylic acid microspheres, 7% polyvinyl alcohol, 5% sodium polyacrylate, and the balance cement are mixed evenly with an appropriate amount of water at 110°C to obtain the reinforcing material.

[0065] Example 8: This example is basically the same as Example 1, except that the particle size of the barium sulfate powder is 50-50.5 μm, the particle size of the microsilica powder is 30-30.5 μm, the average length of the alloy fiber is 1-1.5 mm, the particle size of the zinc oxide powder is 20-20.5 μm, the particle size of the γ-alumina powder is 20-20.5 μm, and the particle size of the aluminum chromium slag powder is 0.2-0.25 mm.

[0066] Example 9: This example is basically the same as Example 1, except that the particle size of the barium sulfate powder is 59.5-60 μm, the particle size of the microsilica powder is 39.5-40 μm, the average length of the alloy fiber is 2.95-3 mm, the particle size of the zinc oxide powder is 39.5-40 μm, the particle size of the γ-alumina powder is 29.5-30 μm, and the particle size of the aluminum chromium slag powder is 4.5-5 mm.

[0067] Example 10: This example is basically the same as Example 1, except that the particle size of the glass flakes includes 20 mesh, 60 mesh and 110 mesh, and the mass ratio is 9:1:1 respectively.

[0068] Example 11: This example is basically the same as Example 1, except that the particle size of the glass flakes includes 20 mesh, 60 mesh and 110 mesh, and the mass ratio is 10:1:1 respectively.

[0069] Example 12: This example is basically the same as Example 1, except that the method of preparing the mixed raw materials is as follows: 50% of glass flakes pretreated with S4-1, 1% of curing agent, 1% of accelerator, 1% of thixotropic stabilizer, 1% of low shrinkage agent, 0.2% of silane coupling agent, 0.2% of defoamer, 0.1% of nano silica and the balance of vinyl ester resin are mixed evenly to obtain the surface material.

[0070] Example 13: This example is basically the same as Example 1, except that the method of preparing the mixed raw materials is as follows: 60% of the glass flakes pretreated with S4-1, 3% of the curing agent, 3% of the accelerator, 2% of the thixotropic stabilizer, 12% of the low shrinkage agent, 1.2% of the silane coupling agent, 1% of the defoamer, 3% of the nano silica, and the balance of the vinyl ester resin are mixed evenly to obtain the surface material.

[0071] Comparative Example 1: Referring to Example 1, without laying a splicing layer, the reinforcing material is directly poured into the flue, and after drying, the surface material is poured.

[0072] Comparative Example 2: Referring to Example 1, no reinforcing material was poured; the surface material was poured directly.

[0073] Comparative Example 3: Referring to Example 1, no surface layer material was poured.

[0074] Comparative Example 4: Referring to Example 1, no mesh galvanized steel wire was laid when preparing the splicing layer.

[0075] To investigate the performance of the castables produced in Examples 1-7, 12, and 13, and Control Examples 1-4, the main materials were determined according to the experimental formulation, and 13 sets of samples were prepared for testing. The specific investigation is as follows:

[0076] Figure 2 In the middle: Condition 1 is to place at 200℃ for 3 hours; Condition 2 is to place at 200℃ for 36 hours;

[0077] 1. Investigate the effect of the mixing ratio of powders on the properties of castables:

[0078] like Figure 1 , 2 As shown in the comparison of Examples 1 to 3, it can be seen that the overall performance of Example 1 is better; changing the mixing powder ratio parameters will have a certain impact on the prepared castable samples. Among them, the castable prepared with process parameter values ​​close to those of Example 1 has better overall performance.

[0079] 2. Investigate the influence of process parameters for preparing the splicing layer on the properties of the castable:

[0080] like Figure 1 , 2 As shown, a comparison of Examples 1, 4, and 5 reveals that Example 1 exhibits superior overall performance. Changing the process parameters for preparing the splicing layer will have a certain impact on the prepared castable sample, with the castable sample whose process parameter values ​​are closer to those of Example 1 exhibiting the best overall performance.

[0081] like Figure 1 , 2As shown, a comparison between Example 1 and Comparative Example 1 shows that the overall performance of Example 1 is significantly better than that of Comparative Example 1. Compared with not laying the splicing layer, directly pouring the reinforcing material into the flue and then pouring the surface material after drying, the sample with the splicing layer has better overall performance. A comparison between Example 1 and Comparative Example 4 shows that the compressive strength performance of Example 1 is significantly better than that of Comparative Example 4. The addition of the mesh galvanized steel wire has a significant impact on the durability and compressive strength of the castable.

[0082] 3. Investigate the effect of the proportion of the reinforcing material on the properties of the castable:

[0083] like Figure 1 , 2 As shown, a comparison of Examples 1, 6, and 7 reveals that the castable prepared according to the method of Example 1 has the best overall performance. This indicates that the proportion of reinforcing material can have a certain impact on the performance of the castable, but the effect is not significant. The proportion of reinforcing material affects the compressive strength and weather resistance of the castable, and a suitable proportion can improve the overall performance.

[0084] A comparison between Example 1 and Comparative Example 2 shows that the compressive strength of Example 1 is significantly better than that of Comparative Example 2, indicating that the reinforcing material has a more significant effect on the castable.

[0085] 4. Investigate the effect of the formulation ratio of the surface layer material on the performance of the castable:

[0086] like Figure 1 , 2 As shown, comparing Examples 1, 12, and 13 reveals that: the compressive strength of Examples 1, 12, and 13 is similar; the castable prepared in Example 1 has the best weather resistance; the proportion of the surface material has a certain impact on the performance of the castable, but the effect is not significant; compared with Control Example 3, Example 1 has little difference in compressive strength, but the difference in durability is more obvious.

Claims

1. A method for preparing flue gas casting material to reduce gas corrosion in fluidized bed boilers, characterized in that, Includes the following steps: S1, Mixed Powder Ingredients By mass percentage, 12-14% barium sulfate powder, 10-12% microsilica powder, 3-8% alloy fiber, 1-8% zinc oxide powder, 3-5% γ-alumina powder, and the balance aluminum chromium slag powder are mixed evenly to obtain a mixed powder. S2, Prepare the splicing layer Measure the dimensions of the flue to be poured, select several sheet-like molds matching these dimensions, the molds being 0.5~3cm thick, introduce mixed powder into the molds, press them into shape, and hold them at 1000~1800℃ for 0.5~1h. After cooling, lay a layer of polytetrafluoroethylene (PTFE) film on its surface, then lay a layer of basalt fiber cloth or aramid fiber cloth on the PTFE film, followed by another layer of PTFE film, and finally evenly lay a layer of mesh galvanized steel wire. Hold it at 90~110℃ for 12~24h, and after cooling, demold to obtain the spliced ​​layer; the thickness of each of the two PTFE films is 0.08~0.3mm, the thickness of the basalt fiber cloth or aramid fiber cloth is 0.4~0.5mm, and the average thickness of the mesh galvanized steel wire is 0.5~2.5mm. S3, Preparation of reinforcing material By weight percentage, 15-25% titanium carbide powder, 15-18% biochar powder, 10-15% perlite, 2-15% fused magnesia powder, 8-14% glass microspheres, 5-10% polyacrylic acid microspheres, 2-7% polyvinyl alcohol, 2-5% sodium polyacrylate, and the balance cement are mixed with an appropriate amount of water at 90-110℃ to obtain the reinforcing material. S4. Preparation of anti-corrosion flue casting material S4-1, Pre-treatment of glass flakes; S4-2, Preparation of surface material; S4-3. Adjust the viscosity of the surface material, splice the splicing layer onto the inner wall of the flue, then pour the reinforcing material, let it dry, and then pour the surface material. By combining the raw materials according to the above operations, a flue casting material that reduces gas corrosion can be obtained. The method for preparing the surface material described in S4-2 is as follows: by mass percentage, 50-60% of the glass flakes pretreated in S4-1, 1-3% of the curing agent, 1-3% of the accelerator, 1-2% of the thixotropic stabilizer, 1-12% of the low-shrinkage agent, 0.2-1.2% of the silane coupling agent, 0.2-1% of the defoamer, 0.1-3% of the nano-silica, and the balance of the vinyl ester resin are mixed evenly to obtain the surface material.

2. The method for preparing flue gas casting material for reducing gas corrosion in fluidized bed boilers according to claim 1, characterized in that, The barium sulfate powder in S1 has a particle size of 50-60 μm, the microsilica powder has a particle size of 30-40 μm, the alloy fiber has an average length of 1-3 mm, the zinc oxide powder has a particle size of 20-40 μm, the γ-alumina powder has a particle size of 20-30 μm, and the aluminum chromium slag powder has a particle size of 0.2-5 mm.

3. The method for preparing flue gas casting material for reducing gas corrosion in a fluidized bed boiler according to claim 1, characterized in that, The method for pretreating glass flakes described in S4-1 is as follows: clean the glass flake raw materials with acetone of 95-98% by mass or alcohol of 99-99.9% by mass, polish the surface of the glass flakes, dry them, and then acid wash them.

4. The method for preparing a flue gas casting material for reducing gas corrosion in a fluidized bed boiler according to claim 3, characterized in that, The glass flakes have particle sizes of 20 mesh, 60 mesh, and 110 mesh, with mass ratios of 9 to 10:1:1, respectively.

5. The method for preparing a flue gas casting material for reducing gas corrosion in a fluidized bed boiler according to claim 1, characterized in that, The curing agent is 328E; the accelerator is an organotin compound or a tertiary amine compound; the thixotropic stabilizer is BYK-R605; the low-shrinkage agent is polyamide; the defoamer is BYK-555; and the silane coupling agent is propyltrimethoxysilane.

6. The method for preparing flue gas casting material for reducing gas corrosion in a fluidized bed boiler according to claim 1, characterized in that, The method for adjusting the viscosity of the surface material described in S4-3 is as follows: during the stirring process, an appropriate amount of diluent or thickener is added evenly to adjust the casting viscosity of the surface material to 0.5~1 Pa·s.

7. The method for preparing a flue gas casting material for reducing gas corrosion in a fluidized bed boiler according to claim 6, characterized in that, The diluent is one or any combination of methanol, ethanol, acetone, methyl ethyl ketone, butyl acetate, and ethyl acetate, and the thickener is one or a combination of fumed silica and bentonite.

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