Composite corundum wear-resistant plastic for CFB target area and preparation method thereof
By using boron nitride composite corundum particles and binders to prepare a composite corundum wear-resistant plastic in the target area of a CFB boiler, the problem of severe wear of refractory materials under high-temperature environments was solved, and the service life and wear resistance of the boiler were improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- YIXING XINGBEI FIRE INSULATION ENG CO LTD
- Filing Date
- 2024-05-23
- Publication Date
- 2026-06-09
Smart Images
Figure CN118619690B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of refractory materials technology, specifically to a composite corundum wear-resistant plastic for CFB target areas and its preparation method. Background Technology
[0002] CFB boilers are an advanced boiler technology widely used in the energy industry. Their main principle is to suspend solid fuel using a gaseous or liquid fluidizing agent, creating a fluid bed that increases the contact area between the fuel and the gas, thereby improving combustion efficiency. Due to its numerous advantages, including wide fuel adaptability, high combustion efficiency, large load adjustment, simple fuel preparation system, and ease of comprehensive ash and slag utilization, it is widely used in steam production, heating, combined heat and power (CHP) systems, and power plant boilers.
[0003] The target area of a CFB boiler is the main region where high-dust-laden airflow undergoes high-speed rotation within the separator and is impacted by centrifugal force. Therefore, the impact on the CFB boiler target area is very severe. To withstand the high temperatures generated during CFB boiler operation, the target area is currently mostly made of refractory materials. However, these refractory materials have poor thermal shock resistance and suffer severe erosion and wear under high-temperature conditions, leading to easy detachment of the refractory material from the target area. This necessitates frequent maintenance and significantly impacts the service life of the CFB boiler. Summary of the Invention
[0004] To address the aforementioned problems, this invention provides a composite corundum wear-resistant plastic for CFB target areas and its preparation method.
[0005] The technical solution of the present invention is: a composite corundum wear-resistant plastic for CFB target areas, characterized in that it comprises the following components by weight: 30-40 parts of boron nitride composite corundum particles, 10-30 parts of bauxite particles, 10-20 parts of mullite powder, 15-30 parts of silicon carbide powder, 4-8 parts of calcium aluminate cement, 10-15 parts of binder, and 2-5 parts of additives.
[0006] Note: The above-mentioned plastic has excellent refractory properties and uses boron nitride composite corundum particles as aggregate. The boron nitride composite corundum particles have good high-temperature lubrication and thermal shock resistance, which enables the plastic to maintain good wear resistance in high-temperature environments, reducing erosion and wear in the target area of the CFB boiler and improving the service life of the CFB boiler.
[0007] Furthermore, the binder comprises, by weight, 9-12 parts of a phosphoric acid solution with a mass concentration of 50-60% and 1-3 parts of aluminum hydroxide powder.
[0008] Note: The above-mentioned binder has good adhesive properties, which can effectively ensure the strength of plastics. The binder also has good heat resistance and still has good adhesive properties in high-temperature environments.
[0009] Furthermore, the additives include, by weight, 1-3 parts sodium tripolyphosphate and 1-2 parts sodium borate.
[0010] Note: The above additives can improve the high-temperature resistance of plastics and enhance their flowability, making them easier to flow and fill during molding.
[0011] Furthermore, the particle size of the bauxite particles is ≤6mm, the particle size of the mullite powder is ≤3mm, and the particle size of the silicon carbide powder is ≤0.1mm.
[0012] Note: Limiting the particle size ensures a uniform distribution of components within the plastic and prevents large particles from forming inside, which could lead to defects in the plastic.
[0013] Furthermore, the preparation method of the boron nitride composite corundum particles includes the following steps:
[0014] S1. Add corundum particles and silane coupling agent to ethanol solution and stir for 15-20 min to obtain a mixture; wherein the mass ratio of corundum particles, silane coupling agent and ethanol solution is 1:0.2-0.4:5-8.
[0015] S2. Under stirring, the mixture is heated at a rate of 3-5℃ / min. During the heating process, melamine is added to the mixture every 2-3 minutes. The amount of melamine added at one time accounts for 2-5% of the total mass of the corundum particles. The mixture temperature is maintained at 50-60℃ for 30-35 minutes. The mixture is then filtered and dried to obtain corundum particles loaded with melamine.
[0016] S3. Place the melamine-loaded corundum particles into a boric acid solution, stir for 5-10 minutes, then shake the boric acid solution at 60-80°C for 2-3 hours. After the boric acid solution cools to room temperature, filter and dry to obtain corundum particles loaded with the precursor. The mass ratio of the melamine-loaded corundum particles to the boric acid solution is 1:3-5.
[0017] S4. Under a protective atmosphere, the corundum particles with the supported precursor are calcined at 1200-1350℃ for 3-4 hours to obtain boron nitride composite corundum particles.
[0018] Explanation: The above method loads melamine onto the surface of corundum particles, reacts melamine with boric acid, and then generates boron nitride in situ on the corundum particles after calcination. Boron nitride improves the high-temperature lubrication performance of the corundum particles and enhances the wear resistance of the plastic, thereby increasing the service life of the CFB boiler.
[0019] Furthermore, the ethanol solution has a mass concentration of 50-75%; the boric acid solution has a temperature of 70-80°C and a mass concentration of 10-15%.
[0020] Note: Limiting the concentration of the ethanol solution ensures that melamine can be effectively dissolved, and limiting the concentration of the boric acid solution ensures that boric acid and melamine react fully.
[0021] Furthermore, the particle size of the corundum particles is ≤2mm.
[0022] Note: The corundum particles of the above particle size have a large specific surface area, which can ensure that melamine can be effectively loaded on the surface of the corundum particles.
[0023] Further, the silane coupling agent is any one or a mixture of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane or vinyltriethoxysilane in any proportion.
[0024] Note: The above-mentioned silane coupling agent can form chemical bonds between melamine and corundum particles, so that melamine is tightly loaded on the surface of corundum particles.
[0025] On the other hand, the present invention provides a method for preparing a composite corundum wear-resistant plastic for CFB target areas, comprising the following steps:
[0026] Step 1: Place the boron nitride composite corundum particles, calcium aluminate cement, bauxite particles, mullite powder, silicon carbide powder, and additives into a mixing device and stir evenly to obtain a mixture.
[0027] Step 2: Add water, which accounts for 10-20% of the total mass of the mixture, and then stir the mixture. During the stirring process, gradually add the binder to the mixture until all the binder has been added. Continue stirring for 10-25 minutes to obtain a plastic. The amount of binder added per minute accounts for 5-10% of the total mass.
[0028] Note: The plastic prepared by the above method has a uniform internal composition, fewer internal defects, and the binder is evenly distributed within the plastic, which can effectively bond the internal components and ensure the molding strength of the plastic.
[0029] The beneficial effects of this invention are:
[0030] (1) The plastic of the present invention has excellent refractory properties and uses boron nitride composite corundum particles as aggregate. The boron nitride composite corundum particles have good high-temperature lubrication properties and thermal shock resistance properties, so that the plastic can still have good wear resistance in high-temperature environment, reduce the scouring and wear of the target area of CFB boiler, and improve the service life of CFB boiler.
[0031] (2) This invention loads melamine on the surface of corundum particles, reacts melamine with boric acid, and then generates boron nitride in situ on the corundum particles after calcination. The boron nitride improves the high-temperature lubrication performance of the corundum particles and enhances the wear resistance of the plastic, thereby improving the service life of the CFB boiler.
[0032] (3) The plastic prepared by the method of the present invention has uniform internal components, fewer internal defects, and the binder is evenly distributed in the plastic, which can effectively bond the internal components and ensure the molding strength of the plastic. Attached Figure Description
[0033] Figure 1 This is a line graph of the sample mass loss rate in Experimental Example 1 of this invention;
[0034] Figure 2 This is a line graph of the sample mass loss rate in Experimental Example 2 of this invention;
[0035] Figure 3 This is a line graph of the sample mass loss rate in Experimental Example 3 of this invention;
[0036] Figure 4 This is a line graph of the sample mass loss rate in Experimental Example 4 of this invention;
[0037] Figure 5 This is a line graph of the sample mass loss rate in Experimental Example 5 of this invention;
[0038] Figure 6 This is a line graph of the sample mass loss rate in Experimental Example 6 of this invention;
[0039] Figure 7 This is a line graph showing the sample mass loss rate of Experimental Example 7 of this invention. Detailed Implementation
[0040] 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.
[0041] Example 1: A composite corundum wear-resistant plastic for CFB target areas, comprising the following components by weight: 35 parts boron nitride composite corundum particles, 20 parts bauxite particles, 15 parts mullite powder, 22 parts silicon carbide powder, 6 parts calcium aluminate cement, 12 parts binder, and 4 parts additives.
[0042] The binder comprises, by weight, 10 parts of a 55% phosphoric acid solution and 2 parts of aluminum hydroxide powder; the additive comprises, by weight, 2.5 parts of sodium tripolyphosphate and 1.5 parts of sodium borate.
[0043] The particle size of the bauxite particles is ≤6mm, the particle size of the mullite powder is ≤3mm, and the particle size of the silicon carbide powder is ≤0.1mm.
[0044] The method for preparing the boron nitride composite corundum particles includes the following steps:
[0045] S1. Add corundum particles and silane coupling agent to ethanol solution and stir for 18 min to obtain a mixture; wherein, the mass ratio of corundum particles, silane coupling agent and ethanol solution is 1:0.3:6; the mass concentration of ethanol solution is 60%; the particle size of corundum particles is ≤2mm; and the silane coupling agent is 3-aminopropyltrimethoxysilane.
[0046] S2. Under stirring, the mixture is heated at a rate of 4℃ / min. During the heating process, melamine is added to the mixture every 2.5min. The amount of melamine added at one time accounts for 4% of the total mass of the corundum particles. The mixture temperature is maintained at 55℃ for 32min. Then the mixture is filtered and dried to obtain corundum particles loaded with melamine.
[0047] S3. Melamine-loaded corundum particles are placed in a boric acid solution and stirred for 8 minutes. The boric acid solution is then shaken at 70°C for 2.5 hours using a constant temperature shaker. After the boric acid solution cools to room temperature, it is filtered and dried to obtain corundum particles loaded with the precursor. The mass ratio of melamine-loaded corundum particles to boric acid solution is 1:4. The temperature of the boric acid solution is 75°C, and the mass concentration is 12%.
[0048] S4. Under a nitrogen protective atmosphere, the corundum particles with the supported precursor were calcined at 1300℃ for 3.5h to obtain boron nitride composite corundum particles.
[0049] The above-mentioned method for preparing plastic includes the following steps:
[0050] Step 1: Place the boron nitride composite corundum particles, calcium aluminate cement, bauxite particles, mullite powder, silicon carbide powder, and additives into a mixing device and stir evenly to obtain a mixture.
[0051] Step 2: Add water at a rate of 15% of the total mass to the mixture, then stir the mixture and gradually add the binder to the mixture during the stirring process until all the binder has been added. Continue stirring for 20 minutes to obtain a plastic; wherein the amount of binder added per minute is 8% of the total mass.
[0052] Example 2: This example is basically the same as Example 1, except that the raw materials include the following components by weight: 30 parts boron nitride composite corundum particles, 10 parts bauxite particles, 10 parts mullite powder, 15 parts silicon carbide powder, 4 parts calcium aluminate cement, 10 parts binder, and 2 parts additives.
[0053] Example 3: This example is basically the same as Example 1, except that the raw materials include the following components by weight: 40 parts boron nitride composite corundum particles, 30 parts bauxite particles, 20 parts mullite powder, 30 parts silicon carbide powder, 8 parts calcium aluminate cement, 15 parts binder, and 5 parts additives.
[0054] Example 4: This example is basically the same as Example 1, except that the mass ratio of corundum particles, silane coupling agent and ethanol solution is 1:0.2:5.
[0055] Example 5: This example is basically the same as Example 1, except that the mass ratio of corundum particles, silane coupling agent and ethanol solution is 1:0.4:8.
[0056] Example 6: This example is basically the same as Example 1, except that the mixture is heated at a rate of 3°C / min until the temperature of the mixture rises to 50°C.
[0057] Example 7: This example is basically the same as Example 1, except that the mixture is heated at a rate of 5°C / min until the temperature of the mixture rises to 60°C.
[0058] Example 8: This example is basically the same as Example 1, except that the amount of melamine added at one time accounts for 2% of the total mass of the corundum particles.
[0059] Example 9: This example is basically the same as Example 1, except that the amount of melamine added at one time accounts for 5% of the total mass of the corundum particles.
[0060] Example 10: This example is basically the same as Example 1, except that the mass ratio of corundum particles loaded with melamine to boric acid solution is 1:3.
[0061] Example 11: This example is basically the same as Example 1, except that the mass ratio of corundum particles loaded with melamine to boric acid solution is 1:5.
[0062] Example 12: This example is basically the same as Example 1, except that the corundum particles of the loaded precursor are calcined at 1200°C for 3 hours.
[0063] Example 13: This example is basically the same as Example 1, except that the corundum particles of the loaded precursor are calcined at 1350°C for 4 hours.
[0064] Example 14: This example is basically the same as Example 1, except that the amount of binder added per minute accounts for 5% of its total mass.
[0065] Example 15: This example is basically the same as Example 1, except that the amount of binder added per minute accounts for 10% of its total mass.
[0066] Comparative Example 1: Referring to Example 1, the boron nitride composite corundum particles were replaced with ordinary corundum particles.
[0067] Comparative Example 2: Referring to Example 1, the boron nitride composite corundum particles were replaced with a mixture of 25 parts ordinary corundum particles and 10 parts boron nitride powder.
[0068] Comparative Example 3: Referring to Example 1, the mass ratio of corundum particles, silane coupling agent and ethanol solution was 1:0.1:4.
[0069] Comparative Example 4: Referring to Example 1, the mass ratio of corundum particles, silane coupling agent and ethanol solution was 1:0.5:9.
[0070] Comparative Example 5: Referring to Example 1, the mixture was heated at a rate of 2°C / min.
[0071] Comparative Example 6: Referring to Example 1, the mixture was heated at a rate of 6°C / min.
[0072] Comparative Example 7: Referring to Example 1, melamine was added in a single step.
[0073] Comparative Example 8: Referring to Example 1, the mass ratio of corundum particles loaded with melamine to boric acid solution was 1:2.
[0074] Comparative Example 9: Referring to Example 1, the mass ratio of corundum particles loaded with melamine to boric acid solution was 1:6.
[0075] Comparative Example 10: Referring to Example 1, corundum particles with the loaded precursor were calcined at 1100°C for 3.5 h.
[0076] Comparative Example 11: Referring to Example 1, corundum particles with a loaded precursor were calcined at 1450°C for 3.5 h.
[0077] Comparative Example 12: Referring to Example 1, the binder was added in a single step.
[0078] Experimental Example: To investigate the influence of parameters in each embodiment on the wear resistance of plastics, plastic samples of each embodiment were prepared into 160mm×40mm×40mm specimens. After drying for 48 hours, the specimens were fired at 1500℃ for 3 hours. The fired specimens were then removed and subjected to erosion wear tests using an erosion wear testing machine. Brown corundum particles were used as the abrasive, the erosion temperature was 1000℃, and the erosion time was 2 hours. The mass loss rate of each specimen before and after erosion wear was calculated. The specific investigation is as follows:
[0079] 1. Investigate the influence of raw material composition on the properties of plastics.
[0080] like Figure 1 As shown, a comparison of Examples 1, 2, and 3 reveals that the sample mass loss rate of Example 1 is the lowest, indicating that the wear resistance of the plastic in Example 1 is the best. This may be because the internal structure of the plastic in Example 1 is more uniform and has fewer defects, thus the raw material composition selected in Example 1 is optimal.
[0081] As can be seen from the comparison between Example 1 and Comparative Examples 1 and 2, after replacing the boron nitride composite corundum particles with ordinary corundum particles, the wear resistance of the sample decreased significantly. This may be because boron nitride can effectively improve the high-temperature lubricity of plastics. When boron nitride is added directly to the raw material in powder form, the wear resistance of the sample is improved, but the improvement is not significant. This may be because the directly added boron nitride powder will detach from the corundum matrix during the wear process, causing the plastic to lose its high-temperature lubricity.
[0082] 2. Investigate the effect of mixture ratio on plastic properties.
[0083] like Figure 2 As shown, a comparison of Examples 1, 4, and 5 with Comparative Examples 3 and 4 reveals that as the ratio of silane coupling agent to ethanol solution increases, the mass loss rate of the sample gradually decreases until the mass loss rate of the sample in Example 1 reaches its lowest value. As the ratio of silane coupling agent to ethanol solution continues to increase, the mass loss rate of the sample does not change significantly. This may be because the amount of melamine that corundum particles can support is limited. Therefore, from a cost perspective, the mixed solution ratio selected in Example 1 is optimal.
[0084] 3. Investigate the effect of heating parameters of the mixed solution on the properties of plastics.
[0085] like Figure 3 As shown, by comparing Examples 1, 6, and 7 with Comparative Examples 5 and 6, it can be seen that the sample mass loss rate of Example 1 is the smallest, indicating that the wear resistance of the plastic in Example 1 is the best. This may be because the heating parameters selected in Example 1 can fully dissolve melamine and form chemical bonds between corundum particles. Therefore, the heating parameters of the mixture selected in Example 1 are the optimal.
[0086] 4. Investigate the effect of melamine addition amount on plastic properties.
[0087] like Figure 4 As shown in the comparison of Examples 1, 8, and 9, it can be seen that as the amount of melamine added increases, the mass loss rate of the sample gradually decreases. However, the mass loss rates of the samples in Examples 1 and 9 are not significantly different. This may be because the amount of melamine that corundum particles can support is limited. Therefore, from a cost perspective, the amount of melamine added in Example 1 is optimal.
[0088] As can be seen from the comparison between Example 1 and Comparative Example 7, the wear resistance of the sample decreased after melamine was added in one go. This may be because the melamine could not be fully dissolved during the one-time addition, resulting in the melamine not being uniformly loaded on the surface of the corundum particles. Therefore, the melamine addition method selected in Example 1 is the optimal one.
[0089] 5. Investigate the effect of boric acid solution ratio on the properties of plastics.
[0090] like Figure 5 As shown, a comparison of Examples 1, 10, and 11 with Comparative Examples 8 and 9 reveals that as the proportion of boric acid solution increases, the mass loss rate of the sample gradually decreases until the mass loss rate of the sample in Example 1 reaches its lowest value. As the proportion of boric acid solution continues to increase, the mass loss rate of the sample does not change significantly. This may be because the reaction amount between melamine and boric acid is limited. Therefore, from the perspective of composition, the proportion of boric acid solution selected in Example 1 is optimal.
[0091] 6. Investigate the effects of calcination parameters on the properties of plastics.
[0092] like Figure 6 As shown, a comparison of Examples 1, 12, and 13 with Comparative Examples 10 and 11 reveals that the sample mass loss rate of Example 1 is the lowest, indicating that the wear resistance of the plastic in Example 1 is the best. This may be because the boron nitride conversion rate is higher in Example 1, thus the calcination parameters selected in Example 1 are optimal.
[0093] 7. Investigate the effect of binder addition rate on plasticity properties.
[0094] like Figure 7 As shown, a comparison of Examples 1, 14, and 15 reveals that the sample mass loss rate of Example 1 is the lowest, indicating that the wear resistance of the plastic in Example 1 is the best. This may be because the binder in Example 1 is more evenly distributed within the plastic, thus the binder addition rate selected in Example 1 is optimal.
[0095] As can be seen from the comparison between Example 1 and Comparative Example 12, the wear resistance of the sample decreased after the binder was added in one go. This may be because the binder could not be evenly distributed in the plastic due to the one-time addition. Therefore, the binder addition method selected in Example 1 is the optimal one.
Claims
1. A composite corundum wear-resistant plastic material for CFB target areas, characterized in that, The components, by weight, include: 30-40 parts boron nitride composite corundum particles, 10-30 parts bauxite particles, 10-20 parts mullite powder, 15-30 parts silicon carbide powder, 4-8 parts calcium aluminate cement, 10-15 parts binder, and 2-5 parts additives; the preparation method of the boron nitride composite corundum particles includes the following steps: S1. Add corundum particles and silane coupling agent to ethanol solution and stir for 15-20 min to obtain a mixture; wherein the mass ratio of corundum particles, silane coupling agent and ethanol solution is 1:0.2-0.4:5-8. S2. Under stirring, the mixture is heated at a rate of 3~5℃ / min. During the heating process, melamine is added to the mixture every 2~3 minutes. The amount of melamine added at one time accounts for 2~5% of the total mass of the corundum particles. The mixture temperature is kept at 50~60℃ for 30~35 minutes. Then the mixture is filtered and dried to obtain corundum particles loaded with melamine. S3. Place the melamine-loaded corundum particles into a boric acid solution, stir for 5-10 minutes, then shake the boric acid solution at 60-80℃ for 2-3 hours. After the boric acid solution cools to room temperature, filter and dry to obtain corundum particles loaded with the precursor. The mass ratio of the melamine-loaded corundum particles to the boric acid solution is 1:3-5. S4. Under a protective atmosphere, the corundum particles with the supported precursor are calcined at 1200~1350℃ for 3~4h to obtain boron nitride composite corundum particles.
2. The composite corundum wear-resistant plastic material for CFB target areas according to claim 1, characterized in that, The binder comprises, by weight, 9-12 parts of a phosphoric acid solution with a mass concentration of 50-60% and 1-3 parts of aluminum hydroxide powder.
3. The composite corundum wear-resistant plastic material for CFB target areas according to claim 1, characterized in that, The additives, by weight, include: 1-3 parts sodium tripolyphosphate and 1-2 parts sodium borate.
4. The composite corundum wear-resistant plastic material for CFB target areas according to claim 1, characterized in that, The particle size of the bauxite particles is ≤6mm, the particle size of the mullite powder is ≤3mm, and the particle size of the silicon carbide powder is ≤0.1mm.
5. The composite corundum wear-resistant plastic material for CFB target areas according to claim 1, characterized in that, The ethanol solution has a mass concentration of 50-75%; the boric acid solution has a temperature of 70-80℃ and a mass concentration of 10-15%.
6. The composite corundum wear-resistant plastic material for CFB target areas according to claim 1, characterized in that, The particle size of the corundum particles is ≤2mm.
7. The composite corundum wear-resistant plastic material for CFB target areas according to claim 1, characterized in that, The silane coupling agent is any one or a mixture of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, or vinyltriethoxysilane in any proportion.
8. A method for preparing a composite corundum wear-resistant plastic for CFB target areas, used to prepare the composite corundum wear-resistant plastic for CFB target areas as described in any one of claims 1 to 7, characterized in that, Includes the following steps: Step 1: Place the boron nitride composite corundum particles, calcium aluminate cement, bauxite particles, mullite powder, silicon carbide powder, and additives into a mixing device and stir evenly to obtain a mixture. Step 2: Add water, which accounts for 10-20% of the total mass of the mixture, and then stir the mixture. During the stirring process, gradually add the binder to the mixture until all the binder has been added. Continue stirring for 10-25 minutes to obtain plastic; wherein the amount of binder added per minute accounts for 5-10% of the total mass.