Glass fiber suitable for offshore wind power blade shell

Abstract

The invention belongs to the technical field of glass fibers, and particularly relates to a glass fiber suitable for an offshore wind power blade shell. The glass fiber suitable for the offshore wind power blade shell is prepared from the following components in percentage by weight: 60.0 to 64.0 percent of SiO2, 13.0 to 16.0 percent of Al2O3, 18.0 to 21.0 percent of CaO, 2.0 to 5.0 percent of MgO, 0.5 to 1.0 percent of La2O3, 0.6 to 1.2 percent of V2O5, 0.02 to 0.5 percent of Li2O, 0.1 to 1.0 percent of Fe2O3, 0.1 to 1.0 percent of TiO2, 0.5 to 1.2 percent of K2O, Na2O and Li2O, and the balance of other inevitable impurities. The industrial solid waste calcined coal series kaolinite and the lithium slag are used as raw materials, so that the raw material and production cost can be remarkably reduced, and the low-carbon and environment-friendly requirements are met.

Description

Technical Field

[0001] This invention belongs to the field of glass fiber technology, and specifically relates to a glass fiber suitable for the shell of offshore wind turbine blades. Background Technology

[0002] Glass fiber, as a widely used inorganic non-metallic fiber material, can be combined with resin to produce high-performance reinforced composite materials, which are widely used in new energy, construction, transportation, chemical industry, and environmental protection. E-glass is the most commonly used type of glass in the production of continuous glass fiber, accounting for 85% of glass fiber reinforced materials. However, traditional E-glass fiber contains boron and fluorine, which not only results in high raw material costs but also causes environmental pollution. In addition, its mechanical properties are weak and its chemical stability is poor, making it difficult to meet the application requirements of high-performance pipes, building materials, ships, and wind power.

[0003] With the transformation of the global energy structure and the strengthening of environmental awareness, offshore wind power has become a cutting-edge field in the global wind power industry. Compared with onshore wind power, offshore wind power has significant advantages such as abundant resources, high power generation utilization hours, no land occupation, and suitability for large-scale development. As the offshore wind power industry continues to develop, glass fiber is also evolving towards higher modulus, lower density, and superior fatigue performance. In the wind power industry, the main spars and trailing edge structure of wind turbine blades require ultra-high modulus glass fiber, while the blade shell, due to cost pressures, mainly uses modified E-type alkali-free glass fiber, which meets the requirements of low cost and high performance. Generally, in large wind turbine blades of 90-100 meters, ECR-type glass fiber fabrics account for up to 69% of the weight.

[0004] Therefore, optimizing and improving E-glass fiber has gradually become an important research direction. In the 1980s, the American company OC developed a modified ECR glass fiber. By adding ZnO and TiO2, its corrosion resistance was significantly improved compared to ordinary E-glass fiber. However, the production process of this modified ECR glass fiber was poor, the glass color was heavy, and the cost was high, limiting its application to scenarios with extremely stringent corrosion resistance requirements. Meanwhile, due to environmental pressures, many glass fiber companies both domestically and internationally began to improve glass fibers by removing boron and fluorine. Chinese patent CN102173594A discloses a boron-free and fluorine-free glass fiber composition. Although removing boron and fluorine reduces the risk of environmental pollution and adding TiO2 and ZnO ensures excellent acid resistance, the production cost remains high. Chinese patent CN109678350A discloses a glass fiber composition and its glass fiber and composite material, also improved by adding TiO2. However, both of these patents exhibit a high calcium content, and the introduction of TiO2 and ZnO significantly increases the material density. Summary of the Invention

[0005] The purpose of this invention is to provide a glass fiber suitable for offshore wind turbine blade shells. This glass fiber has a low glass density, considerable mechanical properties and corrosion resistance, and low production cost. It also has good drawing temperature and liquidus temperature, which can meet the requirements of tank furnace drawing operations and can be mass-produced.

[0006] The glass fiber for offshore wind turbine blade shells described in this invention comprises, by weight percentage, the following components: SiO2 60.0-64.0% Al2O3 13.0-16.0% CaO 18.0-21.0% MgO 2.0-5.0% La2O3 0.5-1.0% V2O5 0.6-1.2% Li2O 0.02-0.5% Fe2O3 0.1-1.0% TiO2 0.1-1.0% K₂O + Na₂O + Li₂O 0.5-1.2% Other unavoidable impurities remaining; in, V₂O₅ / La₂O₃ 1.0-2.0 (SiO2+Al2O3) / (CaO+MgO+V2O5) ≥3.2.

[0007] As a preferred embodiment, the glass fiber used in the shell of offshore wind turbine blades comprises, by weight percentage, the following components: SiO2 60.0-62.0% Al2O3 14.0-16.0% CaO 18.5-19.5% MgO 3.0-4.0% La2O3 0.5-1.0% V2O5 0.6-1.0% Li2O 0.02-0.3% Fe2O3 0.1-1.0% TiO2 0.1-1.0% K₂O + Na₂O + Li₂O 0.5-1.2% Other unavoidable impurities remaining; in, V₂O₅ / La₂O₃ 1.0-1.5 (SiO2+Al2O3) / (CaO+MgO+V2O5) ≥3.3.

[0008] To ensure that the glass fiber has excellent mechanical properties, such as tensile breaking strength, while avoiding excessively high glass clarification temperature and drawing temperature, the total content of SiO2 and Al2O3 is 74-78%, preferably 75-77%.

[0009] The elastic modulus of glass fiber suitable for offshore wind turbine blade shells is above 83 GPa.

[0010] The fiber drawing temperature for glass fiber suitable for offshore wind turbine blade shells is 1270-1300℃.

[0011] The liquidus temperature of glass fiber suitable for offshore wind turbine blade shells is 1150-1200℃.

[0012] The density of the glass fiber used in the shell of offshore wind turbine blades is 2.63 g / cm³. 3 the following.

[0013] The water resistance weight loss rate of glass fiber suitable for offshore wind turbine blade shells is less than 0.6%.

[0014] The glass fiber used in offshore wind turbine blade shells is made from the following raw materials: coal-based kaolin, pyrophyllite, quartz sand, quicklime, magnesite, limestone, lithium slag, vanadium oxide, and lanthanum oxide.

[0015] The components of the glass fiber in this invention are described below: SiO2 forms the network framework of glass and is the most abundant component in most silicate glass compositions. The Si-O bond has high bond energy and stability, forming a dense [SiO4] tetrahedral structure, giving the glass excellent mechanical strength, thermal stability, and chemical stability. However, excessive silicon content can lead to increased glass refining temperature and molding difficulty, resulting in increased production energy consumption. Therefore, it is necessary to rationally control the SiO2 content to achieve the best cost-effectiveness. In this invention, the SiO2 content of the glass fiber used for offshore wind turbine blade shells is 60.0-64.0%, preferably 60.0-62.0%.

[0016] Al2O3 is a network intermediate in glass, with a small amount of Al 3+Non-bridging oxygen can be captured to form aluminum-oxygen tetrahedra and enter the silicon-oxygen network, making the glass structure more compact and thus reducing the coefficient of thermal expansion and improving mechanical properties (especially the elastic modulus). However, the aluminum-oxygen tetrahedron [AlO4] has a larger spatial volume than the silicon-oxygen tetrahedron, resulting in a looser structure. Therefore, a higher Al2O3 content not only increases the coefficient of thermal expansion but also significantly increases the tendency for glass crystallization, leading to excessively high liquidus temperature and excessively fast crystallization rate, which is detrimental to large-scale production in tank furnaces. Therefore, in this invention, the Al2O3 content of the glass fiber suitable for offshore wind turbine blade shells is 13.0-16.0%, preferably 14.0-16.0%.

[0017] La2O3, with its high field strength, attracts surrounding oxygen ions, significantly improving the bonding force of [SiO4] units in the glass network, reducing the number of non-bridging oxygens, and simultaneously promoting the growth of more Al. 3+ Integrating into the glass network structure increases network connectivity, making the glass structure denser and improving its elastic modulus and chemical stability. During the cooling process in glass fiber production, La, due to its larger ionic radius, tends to accumulate on the glass surface, resulting in surface La... 3+ O in the external moisture environment 2- or OH - The reaction can form a dense La-O protective layer, which can slow down the leaching of glass components and improve the water resistance of the glass. However, excessive addition of La can also lead to an increase in glass density and a greater tendency for crystallization. Using a small amount of V₂O₅ instead of CaO can reduce the glass density and improve its temperature resistance and strength; vanadium ions (V₂O₅) can also contribute to the glass's performance. 4+ / V 5+ It can capture the active hydroxyl groups (-OH) generated by water erosion and convert them into stable vanadium oxide groups, thereby blocking the hydrolysis chain reaction of the glass network; at the same time, V2O5 and La 3+ It can form a La-VO composite structure (such as lanthanum vanadate), constructing a dense protective layer on the glass surface, further blocking the diffusion and penetration of water molecules. The introduction of vanadium can significantly enhance the water resistance of La. However, excessive V2O5 will increase the disorder of the bond angles and bond lengths in the tetrahedral structure of the glass, reduce the regularity of the tetrahedral structure, and thus affect the strength of the glass. In the glass fiber of the present invention, suitable for offshore wind turbine blade shells, the La2O3 content is controlled at 0.5-1.0%, the V2O5 content is controlled at 0.6-1.2%, and by limiting the V2O5 / La2O3 ratio to between 1.0-2.0, the strength and water resistance of the glass are optimally balanced.

[0018] MgO and CaO can regulate the crystallization and drawing temperatures of high-modulus glass materials. The influence of divalent alkaline earth metals on the properties of high-modulus glass materials basically follows the law of ionic radius size: with the increase of atomic number and atomic radius, the elastic modulus of high-modulus glass materials tends to decrease, and because it does not cause the expansion of the network structure, the density of the material tends to increase. Magnesium ions have stronger polarization ability than calcium ions and have a better accumulation effect. Therefore, MgO has a greater influence on the elastic modulus of high-modulus glass materials than CaO. When magnesium ions replace calcium ions, they can partially form a tetrahedral structure, which helps to form a denser glass network structure, thereby improving the elastic modulus of the glass. In this invention, the MgO content of the glass fiber suitable for offshore wind turbine blade shells is 2.0-5.0%, preferably 3.0-4.0%. To further control the glass fiber density, this invention controls (SiO2+Al2O3) / (CaO+MgO+V2O5) ≥ 3.2, preferably ≥ 3.3, so that the density of the glass fiber suitable for offshore wind turbine blade shells is 2.63 g / cm³. 3 the following.

[0019] K₂O and Na₂O provide electrical conductivity to molten glass, acting as electro-fluxing agents to improve glass melting efficiency. They also provide a large amount of free oxygen, offering more possibilities for the transformation of aluminum and magnesium ions to 4-coordinate structures, promoting glass densification. However, excessive K₂O and Na₂O content can cause the silicon-oxygen tetrahedra to lose their original integrity and symmetry, resulting in a porous glass structure and deteriorated physical properties. Li₂O, like Na₂O and K₂O, is a network exooxide, but its role in glass is unique; it is not an inert gas ion. Because Li… + radius ratio K + and Na + Smaller Li has a larger electric field strength and plays a "gathering" role in the structure, therefore when Li + Replace K + and Na + When Li is used, it can improve the chemical stability of the glass and, to some extent, suppress the tendency to crystallize. However, when Li... + When the content is too high, the excessive accumulation will cause glass phase separation and promote crystallization tendency. The Li2O content of the glass fiber in the offshore wind turbine blade shell of the present invention is 0.02-0.50%, preferably 0.02-0.30%, while the total content of K2O, Na2O and Li2O is controlled to be 0.5-1.2%.

[0020] The silicon and aluminum elements in the glass fiber of this invention, suitable for offshore wind turbine blade shells, mainly come from natural mineral powders pyrophyllite and kaolin powder. Coal-associated kaolin is a abundant resource found in coal-bearing strata and coal seams, and is currently an important target for deep processing of kaolinite. Carboniferous coal seams contain a large amount of high-quality kaolinite in the interbedded rock and roof and floor plates. During production, kaolinite is extracted as interbedded rock or roof and floor plates, and then discharged as coal gangue through coal preparation plants. Coal gangue is a large-volume solid waste, difficult to treat, and contains coal, with extremely high COD (chemical oxygen demand) content and poor stability. It can be treated through subsequent calcination and iron removal technologies to make its composition close to or better than that of the rock series, suitable for use in pool kiln production. This invention introduces calcined coal-bearing kaolinite, which can significantly reduce production costs while meeting green environmental protection requirements.

[0021] This invention introduces industrial slag (i.e., lithium slag) from lithium extraction processes using raw materials such as spodumene and lepidolite. Recent statistics show that the composition of industrial solid waste is relatively stable, mainly consisting of tailings, mining, and coal combustion. The solid particles in industrial solid waste are primarily composed of oxides of silicon, aluminum, and iron. To more rationally utilize social resources and reduce carbon emissions, it is necessary to develop and research the application of industrial solid waste in glass fiber, enabling the resource recovery of solid waste. Lithium slag tailings have large reserves and low costs. This invention introduces the use of lithium slag, which can further reduce raw material and production costs, create economic benefits, and contribute to sustainable social development.

[0022] The beneficial effects of this invention are as follows: (1) The glass fiber used in this invention for offshore wind turbine blade shells does not contain ZnO. By adding La2O3 and V2O5 and adjusting their ratio, the proportions of Al2O3, CaO, and MgO are optimized, significantly reducing the glass fiber density, increasing the glass fiber elastic modulus, and improving the water resistance of the glass fiber, making it suitable for offshore wind turbine blade shells. By controlling (SiO2+Al2O3) / (CaO+MgO+V2O5)≥3.2, the density of the glass fiber suitable for offshore wind turbine blade shells is 2.63 g / cm³. 3 the following.

[0023] (2) The addition of an appropriate amount of Li2O in this invention can significantly improve the conductivity of the glass melt, enhance the advantages of electric melting, reduce the difficulty of furnace melting, improve the clarification effect, thereby reducing energy consumption and production costs.

[0024] (3) The present invention uses industrial solid waste calcined coal-based kaolin and lithium slag as raw materials, which can significantly reduce raw material and production costs and meet low-carbon and environmental protection requirements, creating economic benefits while contributing to social sustainable development.

[0025] (4) The glass fiber used in the offshore wind turbine blade shell of the present invention has an elastic modulus of more than 83 GPa, a drawing temperature of 1270-1300℃, a liquidus temperature of 1150-1200℃, a low crystallization rate, and a difference ΔT between the drawing temperature and the liquidus temperature of 100℃, which meets the requirements of the pool furnace drawing process and can be mass-produced. Detailed Implementation

[0026] The present invention will be further described below with reference to embodiments.

[0027] Examples 1-8 Based on the content of each component in the glass fiber suitable for offshore wind turbine blade shells, coal-series kaolin, pyrophyllite, quartz sand, quicklime, magnesite, limestone, lithium slag, vanadium oxide, and lanthanum oxide were weighed to prepare glass fiber suitable for offshore wind turbine blade shells.

[0028] The following parameters were selected for the comprehensive performance characterization of glass fiber suitable for offshore wind turbine blade shells: (1) The drawing temperature, which is the temperature at which the viscosity of the glass is 1000 poise, can characterize the forming temperature of the fiber. The high temperature viscosity of the glass is obtained by using a high temperature viscometer. (2) Liquidus temperature, which is the critical temperature at which glass begins to crystallize. It is generally the upper limit of the glass crystallization temperature. The upper limit of the glass crystallization temperature is obtained by using a crystallization furnace. (3) ΔT, the difference between the wire drawing temperature and the liquidus temperature; (4) Density, tested according to the standard test method for determining the density of glass, ASTM C693 buoyancy method; (5) Elastic modulus, tested according to ASTM D2343 standard; (6) Water resistance test: refer to GB / T 33832 standard, soak at 80℃ for 72h, cool, filter, dry, weigh, and calculate water resistance weight loss rate.

[0029] Table 1 shows the glass fiber component content and performance data applicable to offshore wind turbine blade shells in Examples 1-8.

[0030] Table 1. Glass fiber composition content and performance data for offshore wind turbine blade shells in Examples 1-8

[0031] Comparative Example 1 By replacing La2O3 with an equal mass of V2O5 and performing the same other operations as in Example 7, glass fiber suitable for offshore wind turbine blade shells is obtained.

[0032] Comparative Example 2 By replacing V2O5 with an equal mass of La2O3 and performing the same other operations as in Example 7, glass fiber suitable for offshore wind turbine blade shells is obtained.

[0033] Comparative Example 3 The total content of V2O5 and La2O3 is the same as in Example 7, making the V2O5 / La2O3 ratio 2.67. Other operations are the same as in Example 7, resulting in glass fiber suitable for offshore wind turbine blade shells.

[0034] Comparative Example 4 The total content of V2O5 and La2O3 is the same as in Example 7, so that the V2O5 / La2O3 ratio is 0.83. Other operations are the same as in Example 7, and glass fiber suitable for offshore wind turbine blade shells is obtained.

[0035] Comparative Example 5 Adjust the SiO2 to 60%, Al2O3 to 13%, CaO to 18%, MgO to 5.2%, and V2O5 to 1%, so that (SiO2+Al2O3) / (CaO+MgO+V2O5) is 3. Other operations are the same as in Example 7, to obtain glass fiber suitable for offshore wind turbine blade shells.

[0036] Table 2 shows the glass fiber component content and performance data of the comparative examples 1-5 suitable for offshore wind turbine blade shells.

[0037] Table 2. Glass fiber composition content and performance data suitable for offshore wind turbine blade shells in Comparative Examples 1-5.

[0038] Table 2 shows that in Comparative Example 1, replacing La2O3 with an equal mass of V2O5 significantly increased the water resistance weight loss rate and decreased the elastic modulus of the glass fiber suitable for offshore wind turbine blade shells. In Comparative Example 2, replacing V2O5 with an equal mass of La2O3 significantly reduced the difference ΔT between the drawing temperature and the liquidus temperature of the glass fiber suitable for offshore wind turbine blade shells, increased the water resistance weight loss rate and density, and decreased the elastic modulus. In Comparative Example 3, the total content of V2O5 and La2O3 was 2.2%, and the V2O5 / La2O3 ratio was 2.67. This resulted in an increased liquidus temperature and decreased elastic modulus of the glass fiber suitable for offshore wind turbine blade shells. The content of V2O5 and La2O3 in Comparative Example 4 was 2.2%, and the V2O5 / La2O3 ratio was 0.83. The liquidus temperature of the glass fiber suitable for offshore wind turbine blade shells increased, the elastic modulus decreased, and the water resistance weight loss rate increased significantly. In Comparative Example 5, the content of SiO2 was 60%, Al2O3 was 13%, CaO was 18%, MgO was 5.2%, V2O5 was 1%, and the ratio of (SiO2+Al2O3) / (CaO+MgO+V2O5) was 3. The liquidus temperature of the glass fiber suitable for offshore wind turbine blade shells increased significantly, the water resistance weight loss rate increased, and the density increased significantly.

[0039] Based on the above experimental results, it can be seen that by adding La2O3 and V2O5 and adjusting their ratio, and optimizing the composition ratio of Al2O3, CaO, and MgO, this invention can significantly reduce the density of glass fibers, increase their elastic modulus, and improve their water resistance. By controlling (SiO2+Al2O3) / (CaO+MgO+V2O5) ≥ 3.2, the density of glass fibers suitable for offshore wind turbine blade shells is achieved at 2.63 g / cm³. 3 The following makes it suitable for offshore wind turbine blade housings.

Claims

1. A type of glass fiber suitable for offshore wind turbine blade shells, characterized in that, It consists of the following components by weight percentage: SiO2 60.0-64.0% Al2O3 13.0-16.0% CaO 18.0-21.0% MgO 2.0-5.0% La2O3 0.5-1.0% V2O5 0.6-1.2% Li2O 0.02-0.5% Fe2O3 0.1-1.0% TiO2 0.1-1.0% K₂O + Na₂O + Li₂O 0.5-1.2% Other unavoidable impurities remaining; in, V₂O₅ / La₂O₃ 1.0-2.0 (SiO2+Al2O3) / (CaO+MgO+V2O5) ≥3.

2.

2. The glass fiber for offshore wind turbine blade shells according to claim 1, characterized in that, It consists of the following components by weight percentage: SiO2 60.0-62.0% Al2O3 14.0-16.0% CaO 18.5-19.5% MgO 3.0-4.0% La2O3 0.5-1.0% V2O5 0.6-1.0% Li2O 0.02-0.3% Fe2O3 0.1-1.0% TiO2 0.1-1.0% K₂O + Na₂O + Li₂O 0.5-1.2% Other unavoidable impurities remaining; in, V₂O₅ / La₂O₃ 1.0-1.5 (SiO2+Al2O3) / (CaO+MgO+V2O5) ≥3.

3.

3. The glass fiber for offshore wind turbine blade shells according to claim 1, characterized in that... The total content of SiO2 and Al2O3 is 74-78%.

4. The glass fiber for offshore wind turbine blade shells according to claim 3, characterized in that... The total content of SiO2 and Al2O3 is 75-77%.

5. The glass fiber for offshore wind turbine blade shells according to claim 1, characterized in that... The elastic modulus of glass fiber suitable for offshore wind turbine blade shells is above 83 GPa.

6. The glass fiber for offshore wind turbine blade shells according to claim 1, characterized in that... The fiber drawing temperature for glass fiber suitable for offshore wind turbine blade shells is 1270-1300℃.

7. The glass fiber for offshore wind turbine blade shells according to claim 1, characterized in that... The liquidus temperature of glass fiber suitable for offshore wind turbine blade shells is 1150-1200℃.

8. The glass fiber for offshore wind turbine blade shells according to claim 1, characterized in that... The density of the glass fiber used in the shell of offshore wind turbine blades is 2.63 g / cm³. 3 the following.

9. The glass fiber for offshore wind turbine blade shells according to claim 1, characterized in that... The water resistance weight loss rate of glass fiber suitable for offshore wind turbine blade shells is less than 0.6%.

10. The glass fiber for offshore wind turbine blade shells according to claim 1, characterized in that... It is made from the following raw materials: coal-series kaolin, pyrophyllite, quartz sand, quicklime, magnesite, limestone, lithium slag, vanadium oxide, and lanthanum oxide.

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