Heat-insulating castable for catalytic decarbonization hydrogen production device and preparation process of heat-insulating castable

Abstract

The invention provides a heat-insulating castable for a catalytic decarburization hydrogen production device and a preparation process of the heat-insulating castable, and relates to the technical field of high-temperature heat-insulating catalytic decarburization materials. The heat insulation castable for the catalytic decarburization hydrogen production device is prepared from 40%-45% of aluminum silicate microspheres, 10%-14% of kaolin, 7.5%-8.5% of cement, 16%-18% of silicon dioxide, 3.5%-4.5% of potassium mica, 6%-8% of calcined aluminum oxide hollow spheres, 1.2%-1.8% of metal silicon powder, 1.8%-2.2% of Cr2O3, 1.3%-1.7% of polyacrylate, 2.3%-2.7% of explosion-proof fibers and 6.5%-7.5% of water. The problem of embrittlement and pulverization caused by hydrogen permeation of a traditional castable is solved, a revolutionary protection barrier is provided for a hydrogen production device, and the long-standing technical contradiction that high heat preservation must sacrifice strength in the field of refractory materials is overcome, so that the material has excellent heat preservation efficiency and excellent bearing capacity, the service life of the hydrogen production device is remarkably prolonged, and the service life of the hydrogen production device is prolonged. And the problem of equipment failure caused by frequent thermal circulation is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-temperature heat-insulating catalytic decarbonization materials, in particular to a heat-insulating castable for a catalytic decarbonization hydrogen production device and a preparation process thereof. BACKGROUND

[0002] The heat-insulating castable for a catalytic decarbonization hydrogen production device is an environmental-friendly energy conversion material used in high-temperature environments, which mainly provides stable heat-insulating performance and supports catalytic decarbonization reactions. The material maintains structural stability at high temperatures through the synergistic effect of multiple components, effectively reduces energy consumption, and improves the efficiency and environmental friendliness of hydrogen production, which is an important technical support for promoting green energy development.

[0003] The heat-insulating castable used in existing catalytic decarbonization hydrogen production devices is prone to performance degradation, structural damage, and shortened service life in high-temperature and high-humidity environments. The main reason is that traditional materials lack optimal design that balances high strength and durability, making it difficult to effectively resist heat loss caused by thermal radiation and thermal convection at high temperatures. These problems not only reduce the working efficiency of the material, but also increase the operating cost of the device and limit its application range in industrial production. SUMMARY

[0004] To overcome the deficiencies of the prior art, the present application provides a heat-insulating castable for a catalytic decarbonization hydrogen production device and a preparation process thereof, which solves the problem of poor high-temperature resistance affecting service life.

[0005] To achieve the above purpose, the present application realizes the following technical scheme: a heat-insulating castable for a catalytic decarbonization hydrogen production device, which has the following mass percentage composition: aluminum silicate microspheres 40% to 45%; kaolin 10% to 14%; cement 7.5% to 8.5%; silicon dioxide 16% to 18%; potassium mica 3.5% to 4.5%; calcined alumina hollow spheres 6% to 8%; metallic silicon powder 1.2% to 1.8%; Cr2O3 1.8% to 2.2%; polyacrylate 1.3% to 1.7%; explosion-proof fiber 2.3% to 2.7%; water 6.5% to 7.5%.

[0006] Preferably, the aluminum silicate microspheres have a core-shell structure, the inner core is a porous Al2O3-SiO2 composite (porosity ≥ 65%), and the outer shell is a dense nanometer SiO2 coating layer with a thickness of 0.5 to 2 microns.

[0007] Preferably, the Cr2O3 and the metal silicon powder are in-situ reacted at high temperature to form CrSi2 phase and SiC whisker, wherein the CrSi2 phase accounts for 60-70wt% of the total product.

[0008] Preferably, the anti-explosion fiber is polyacrylonitrile-based oxidized fiber, with a length of 1.0±0.2mm and a single-fiber diameter of 8-12μm, and the surface is treated with silane coupling agent.

[0009] A preparation method of a heat-insulating castable for a catalytic decarburization hydrogen production device, comprising: Step one, the aluminum silicate microspheres, kaolin, cement, silicon dioxide, potassium mica, calcined alumina hollow spheres, metal silicon powder, Cr2O3 and polyacrylate are respectively pulverized to 200 mesh; Step two, the powders obtained in step one are mixed, water is added and stirred at 65±3℃ for 40min; Step three, the temperature is lowered to 60℃ and injected into the mold, and calcined in an inert atmosphere with nitrogen content ≥95%, the calcination program is: 150℃×2h → 500℃×3h → 1100℃×2h → 1550±10℃×6h, and the overall cast forms a working layer, a transition layer and a heat insulation layer; Step four, after holding at 92±2℃ for 8-10h, naturally cooling to room temperature.

[0010] Preferably, the mixing operation in step two is specifically implemented as follows: S1. Dry powder mixing: 200rpm×10min; S2. Mixing after injecting 40℃ warm water: 400rpm×20min; S3. Mixing with anti-explosion fiber: 600rpm×10min.

[0011] Preferably, 0.1%-0.3% of sodium hexametaphosphate dispersant based on the total weight of the powder is also added synchronously in step S3.

[0012] Preferably, an axial pressure of 0.6-0.8MPa is applied during calcination in step three, and the flow of the inert atmosphere is controlled at 0.5-1L / min·kg of material.

[0013] Preferably, The working layer has a thickness of 1-3mm and contains continuous CrSi2-SiC phase, with a porosity of ≤5%; The transition layer has a thickness of 2-4mm and contains α-Al2O3 / CrSi2 phase in a ratio of (2-3):1; The heat insulation layer has a thickness of ≥5mm and contains aluminum silicate microspheres in a ratio of ≥75vol%.

[0014] Preferably, the working layer forms a columnar crystal staggered zone at the interface with the transition layer, the columnar crystal is composed of (Al, Cr)2O3 solid solution, the axial size is 20-50 mu m, and the diameter is 5-10 mu m.

[0015] The application provides a heat-insulating castable for a catalytic decarburization hydrogen production device and a preparation process thereof. 1. The application forms a continuous CrSi2-SiC hydrogen barrier layer in the matrix in situ through the synergistic reaction of Cr2O3 and metal silicon in the components, effectively blocks the hydrogen diffusion path, the structure makes the material maintain structural integrity under extreme working conditions with hydrogen at high temperature, completely solves the embrittlement and pulverization problem of traditional castables caused by hydrogen permeation, and provides a revolutionary protective barrier for the hydrogen production device.

[0016] 2. The application realizes ultra-high densification of the working layer while maintaining the high-porosity heat-insulating layer through the bimodal pore structure combined with the gradient pressing process, which solves the long-standing technical contradiction in the refractory material field that high heat preservation must sacrifice strength, so that the material has excellent heat preservation performance and excellent bearing capacity.

[0017] 3. The application constructs a multi-level anti-thermal stress damage mechanism through the columnar crystal strengthening phase based on the gradient interface growth and the surface hydrophobic passivation treatment, which makes the material show excellent anti-cracking performance under quenching and heating conditions, significantly prolongs the service life of the hydrogen production device, and solves the equipment failure problem caused by frequent thermal cycling. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The schematic diagram of the application. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the application.

[0020] Embodiment 1: As shown in the drawings, Figure 1 The application provides a heat-insulating castable for a catalytic decarburization hydrogen production device, and the heat-insulating castable has the following mass percentage composition: alumina-silicate microspheres 40%~45%, through the synergy of pore-dense layer of core-shell structure, realize dual-mode heat conduction block, kaolin 10%~14%, provide nano-scale active aluminum source, drive in-situ growth of mullite needle-like whiskers, cement 7.5%~8.5%, regulate the generation rate of hydrated calcium aluminum melilite, balance low and high temperature strength, silicon dioxide 16%~18%, melt state SiO2viscosity control phase change process, inhibit abnormal growth of CrSi2grains, potassium mica 3.5%~4.5%, interlayer hydroxyl removal to form nano slip surface, dissipate ≥50% thermal stress, calcined alumina hollow spheres 6%~8%, build 300-500μm level thermal radiation scattering unit, infrared reflectivity ≥85%, metallic silicon powder 1.2%~1.8%, by controlling the molar ratio of Si / Cr2O3 1.03~1.08:1, realize Cr2O3conversion rate ≥99%, Cr2O3 1.8%~2.2%, generate <200nm CrSi2grains at 1550℃, form atomic hydrogen diffusion maze path, polyacrylate 1.3%~1.7%, 400℃ decomposition release CO2, build 20~50μm level exhaust microchannel network, explosion-proof fiber 2.3%~2.7%, form C-O-Si covalent bond after silane modification, interface bonding energy is improved to 5.8J / m 2 , water 6.5%~7.5%, maintain Zeta potential -35mV~-40mV, ensure slurry settling stability.

[0021] The alumina-silicate microspheres have a core-shell structure, the inner core is a porous Al2O3-SiO2 composite (porosity ≥65%), and the outer shell is a nano-SiO2 dense coating layer, the thickness of the coating layer is 0.5~2μm, through molecular dynamics simulation verification, when 1.2μm, the hydrogen permeation activation energy reaches 78kJ / mol, the open porosity is <10%, significantly reducing the Knudsen diffusion effect.

[0022] Cr2O3 and metallic silicon powder react in-situ at high temperature to generate CrSi2 phase and SiC whiskers, wherein the proportion of CrSi2 phase in the total amount of product is 60~70wt%, forming a three-dimensional interconnected skeleton, the tortuosity factor τ ≥8.2, the crystal face ratio >80%, the bending strength is improved to 18.3MPa·m 1 / 2 The explosion-proof fiber is polyacrylonitrile-based oxidized fiber, the length is 1.0±0.2mm, the single filament diameter is 8~12μm, and the surface is treated with silane coupling agent, the surface energy of the explosion-proof fiber treated with KH-550 silane is reduced to 28.5mN / m, the wetting angle θ=12°, the single filament diameter 8~12μm corresponds to the critical fiber reinforcement efficiency threshold of aspect ratio 80~120.

[0023] Example 2: A preparation method of a heat-insulating castable for a catalytic decarburization hydrogen production device, comprising: Step one, the aluminum silicate microspheres, kaolin, cement, silicon dioxide, potassium mica, calcined alumina hollow sphere, metal silicon powder, Cr2O3, polyacrylate are respectively crushed to 200 mesh; Step two, the powder obtained in step one is mixed, water is added and stirred at 65±3℃ for 40min; Step three, cool to 60℃ and inject into the mold, calcine in an inert atmosphere with nitrogen content ≥95%, the calcination program is: 150℃×2h → 500℃×3h → 1100℃×2h → 1550±10℃×6h, maintain the oxygen partial pressure ≤3×10 -6 Pa, Cr 3+ Oxidation weight gain rate <0.15wt%, 1550±10℃ segment control accuracy ±5℃, to reduce the Si / Cr2O3 solid phase reaction activation energy to 210kJ / mol, the overall injection forms working layer, transition layer and insulation layer; Step four, after holding at 92±2℃ for 8-10h, naturally cool to room temperature, axial pressure 0.6-0.8MPa, realize (Al,Cr)2O3 columnar crystal axial compression strain ε=0.8%-1.2%, inert atmosphere flow 0.5-1L / min·kg material, gas phase mass transfer coefficient K x Control at 9.2×10 -5 m / s.

[0024] Example 3: Working layer hydrogen permeability ≤1×10 -11 mol·m -1 ·s -1 ·Pa -1 , in line with ASME BPVC-Section VIII hydrogen barrier standard, the columnar crystal staggered area forms cross texture Schmid factor S=0.42, crack propagation work is increased by 3.5 times, columnar crystal interface Cr element segregation concentration 16-18at%, forming nanoscale Cr2O3 particle pinning grain boundary.

[0025] Based on the mass percentage composition provided in the above examples, extreme working condition performance detection and control group experiment are carried out.

[0026] Extreme working condition performance detection:

[0027] Comparison data:

[0028] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and adaptions can be effected without departing from the spirit and scope of the present application, which is not limited to the exact construction and arrangement described. It is intended, therefore, to cover all modifications and adaptions that fall within the scope of the claims and their equivalents.

Claims

1. A heat-insulating castable for a catalytic decarbonization hydrogen production device, characterized in that, The mass percentage of the thermal insulation castable is as follows: Aluminum silicate microspheres: 40%–45%; Kaolin content: 10%–14%; Cement content: 7.5%–8.5%; 16%–18% silicon dioxide; Potassium mica 3.5%–4.5%; Calcined alumina hollow spheres: 6%–8%; Silicon metal powder 1.2%–1.8%; Cr2O3 1.8%~2.2%; Polyacrylate 1.3%–1.7%; Explosion-proof fiber content: 2.3%–2.7%; Water content: 6.5%–7.5%.

2. The heat-insulating castable refractory for a catalytic decarbonization hydrogen production device according to claim 1, characterized in that: The aluminum silicate microspheres have a core-shell structure, with the core being a porous Al2O3-SiO2 composite (porosity ≥65%) and the outer shell being a dense nano-SiO2 coating layer with a thickness of 0.5-2μm.

3. The heat-insulating castable refractory for a catalytic decarbonization hydrogen production device according to claim 1, characterized in that: The Cr2O3 reacts with metallic silicon powder in situ at high temperature to generate CrSi2 phase and SiC whiskers, wherein the CrSi2 phase accounts for 60-70 wt% of the total product.

4. The heat-insulating castable refractory for a catalytic decarbonization hydrogen production device according to claim 1, characterized in that: The explosion-proof fiber is a polyacrylonitrile-based oxidized fiber with a length of 1.0±0.2mm, a single filament diameter of 8~12μm, and its surface is treated with a silane coupling agent.

5. A method for preparing a heat-insulating castable for a catalytic decarbonization hydrogen production device, as described in claims 1-4, characterized in that, include: Step 1: Crush aluminum silicate microspheres, kaolin, cement, silica, potassium mica, calcined hollow alumina spheres, metallic silicon powder, Cr2O3, and polyacrylate to 200 mesh respectively. Step 2: Mix the powder obtained in Step 1, add water and stir at 65±3℃ for 40 minutes; Step 3: Cool down to 60℃ and inject into the mold. Calcinate in an inert atmosphere with nitrogen content ≥95%. The calcination process is: 150℃×2h → 500℃×3h → 1100℃×2h → 1550±10℃×6h. The entire material is injected to form a working layer, a transition layer, and a heat insulation layer. Step 4: Keep warm at 92±2℃ for 8 to 10 hours, then allow to cool naturally to room temperature.

6. The method for preparing a heat-insulating castable for a catalytic decarbonization hydrogen production device according to claim 5, characterized in that: The specific implementation steps of the mixed operation in step two are as follows: S1. Dry powder mixing: 200 rpm × 10 min; S2. Mix after adding 40℃ warm water: 400rpm×20min; S3. Add explosion-proof fiber and mix: 600rpm×10min.

7. The method for preparing a heat-insulating castable for a catalytic decarbonization hydrogen production device according to claim 6, characterized in that: In step S3, sodium hexametaphosphate dispersant, accounting for 0.1% to 0.3% of the total weight of the powder, is added simultaneously.

8. The method for preparing a heat-insulating castable for a catalytic decarbonization hydrogen production device according to claim 5, characterized in that: In step three, an axial pressure of 0.6–0.8 MPa is applied during calcination, and the inert atmosphere flow rate is controlled at 0.5–1 L / min·kg material.

9. A method for preparing a heat-insulating castable for a catalytic decarbonization hydrogen production device according to any one of claims 5, characterized in that: The working layer has a thickness of 1-3 mm, contains continuous CrSi2-SiC phases, and has a porosity of ≤5%. The transition layer has a thickness of 2-4 mm and an α-Al2O3 / CrSi2 phase content ratio of (2-3):

1. The heat insulation layer has a thickness of ≥5mm and an aluminum silicate microsphere content of ≥75% vol.

10. A method for preparing a heat-insulating castable for a catalytic decarbonization hydrogen production device according to claim 5, characterized in that: A columnar crystal interlacing region is formed at the interface between the working layer and the transition layer. The columnar crystals are composed of (Al,Cr)2O3 solid solution, with an axial dimension of 20-50 μm and a diameter of 5-10 μm.

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