Performance test method and application of wind power blade recycled fiber

Abstract

The invention provides a performance testing method and application of recycled fibers of wind power blades. The performance testing method comprises the steps of preparation of an adhesive material, bending resistance testing, determination of the optimal doping proportion of the recycled fibers, durability testing and the like. According to the method, the wind power blade recycled fibers are prepared into the adhesive material, and then the fracture resistance, the aging resistance and the like of the adhesive material are tested, so that the method can be used for testing the performance of different wind power blade recycled fibers and different thermosetting composite material recycled fibers.

Description

Technical Field

[0001] The invention belongs to the technical field of fiber performance testing, and in particular relates to a performance testing method and application of recycled fibers for wind turbine blades. Background Art

[0002] Domestic small-power wind turbines are about to be retired. Wind turbine blades, which account for 14% of the total weight of wind turbines, are the most difficult part to handle. By recycling the fiber materials in wind turbine blades, we can not only reduce the demand for mining and production of new raw materials, but also reduce the consumption of natural resources and achieve sustainable development. However, the recycled fibers of wind turbine blades are non-standard products with a large range of length and diameter variations, and it is impossible to test the recycled fibers using conventional test standards. Without testing, it is impossible to test the bending resistance of the matrix after adding building materials, which brings difficulties to the resource utilization of recycled fibers.

[0003] The present invention aims to provide a performance testing method for recycled fibers obtained after pulverizing wind turbine blades, and to lay a certain technical foundation for the resource application of the recycled fibers based on the test results. Summary of the invention

[0004] In order to solve the problems in the prior art, the present invention provides a performance testing method and application of recycled fibers from wind turbine blades. The method prepares the recycled fibers from wind turbine blades into an adhesive material and then tests its flexural resistance, anti-aging performance, etc. The method can be used to test the performance of recycled fibers from different wind turbine blades and recycled fibers from different thermosetting composite materials.

[0005] The present invention solves the technical problem by adopting the following technical solutions:

[0006] The first object of the present invention is to provide a method for testing the performance of recycled fibers of wind turbine blades, comprising the following steps:

[0007] S1. Preparation of adhesive materials

[0008] The pure acrylic polymer emulsion and the defoamer are mixed and stirred evenly, and then cement, river sand, crushed recycled fiber, and polycarboxylate water reducer are pre-mixed and added to the mixed liquid, and water is added and stirred evenly to obtain a mortar adhesive material;

[0009] S2. Bending performance test

[0010] Pour the evenly stirred adhesive material into the mold, vibrate for 1 minute, smooth the surface, and place it in a standard curing room for 24 hours; the demoulded specimen is then placed in a dry air room for curing for 6 hours, and then the bending strength of the specimen is tested;

[0011] S3. Determine the optimal doping ratio of recycled fibers

[0012] Adjust the fiber doping amount in step S1, and repeat step S2 to detect the bending strength of the specimens under different doping amounts, and find out the specimen with the largest bending strength as the optimal doping ratio;

[0013] S4. Durability test

[0014] Repeat steps S1 and S2 according to the optimal doping ratio of step S3 to make test blocks. After the test blocks are cured under natural conditions for 28 days, they are immersed in 50°C hot water for curing. The flexural properties of the test blocks cured for different times in 50°C hot water are tested respectively to find out the attenuation law of the flexural properties and obtain the durability performance.

[0015] Furthermore, the cement is selected from 42.5 sulphoaluminium cement or 42.5 ordinary silica cement.

[0016] Preferably, the cement is 42.5 sulphoaluminium cement.

[0017] Furthermore, in step S1, pure acrylic polymer emulsion and defoamer are put into a stirring pot and mixed and stirred evenly, then cement, river sand, crushed recycled fiber and polycarboxylic acid water reducer are premixed and added to the mixed liquid, stirred at a low speed for 2 minutes, and then water is added and stirred evenly to obtain a mortar adhesive material.

[0018] Furthermore, the mass ratio of the cement to the river sand is 1:1.

[0019] Furthermore, the amount of the water reducing agent added is 1.6‰ of the total mass of the mortar, and the amount of the defoaming agent added is 1% of the mass of the polymer.

[0020] Furthermore, the amount of the recycled fiber added is 1-14% of the mass of the cement.

[0021] Preferably, the added amount of the recycled fiber is 2-10% of the mass of cement.

[0022] Furthermore, the conditions of the standard curing room are a temperature of 20±2°C, a humidity greater than 90%, and regular spraying.

[0023] Furthermore, the conditions of the dry air chamber are a temperature of 20±2° C. and a humidity of 60%.

[0024] Furthermore, the cement and river sand are cured in a dry room for 24 hours before use.

[0025] Furthermore, the bending strength test was completed using an electronic universal testing machine. During the test, the test force-axial deformation curve was recorded, and the bending limit load (Pm) was read. The thickness (h) and width (b) of each group of specimens were measured, and the bending strength was calculated using the following formula:

[0026] Then the flexural strength was averaged.

[0027] Furthermore, in the durability test of step S4, the bending resistance after curing in 50° C. hot water for 28 days, 67 days, 93 days and 243 days is respectively selected.

[0028] Furthermore, the curing under natural conditions refers to placing the specimen at a temperature not lower than 5°C and spraying water on the specimen at regular intervals.

[0029] Furthermore, the curing under 50°C hot water immersion refers to curing the test piece by immersing it in 50°C hot water.

[0030] Furthermore, a fluidity test is performed before the bending resistance test. The test method is: a metal ring is placed at the center of the glass plate, and the adhesive material obtained in step S1 is injected into the metal ring. After the metal ring is filled, the metal ring is knocked to remove the internal air, and the adhesive material plane on the upper part of the metal ring is smoothed. The metal ring is lifted to allow the adhesive material to diffuse freely on the glass plate, and the diameter of the ring covered by the adhesive material is recorded as the fluidity.

[0031] The second object of the present invention is to provide a performance testing method for recycled fibers of wind turbine blades for application in the selection of application fields and application areas of the recycled fibers.

[0032] Compared with the prior art, the beneficial technical effects of the present invention are:

[0033] The present invention provides a performance testing method and application of wind turbine blade recycled fibers. The method can be used to test the performance of different wind turbine blade recycled fibers and recycled fibers of different thermosetting composite materials by preparing the recycled fibers into adhesive materials and then testing the flexural resistance and anti-aging performance of the materials. The present invention can provide a basis for what industry field and what regional products the recycled fibers can be used for based on the performance of the recycled fibers tested, and has strong engineering practical significance.

[0034] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary illustrations and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0036] In addition, unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods. The pure acrylic polymer emulsion used in the present invention was purchased from Donglian Chemical, and the liquid defoamer was purchased from Excellence East.

[0037] A method for testing the performance of recycled fibers of wind turbine blades, comprising the following steps:

[0038] S1. Preparation of adhesive materials

[0039] The pure acrylic polymer emulsion and the defoamer are mixed and stirred evenly, and then cement, river sand, crushed recycled fiber, and polycarboxylate water reducer are pre-mixed and added to the mixed liquid, and water is added and stirred evenly to obtain a mortar adhesive material;

[0040] S2. Bending performance test

[0041] Pour the evenly stirred adhesive material into the mold, vibrate for 1 minute, smooth the surface, and place it in a standard curing room for 24 hours; the demoulded specimen is then placed in a dry air room for curing for 6 hours, and then the bending strength of the specimen is tested;

[0042] S3. Determine the optimal doping ratio of recycled fibers

[0043] Adjust the fiber doping amount in step S1, and repeat step S2 to detect the bending strength of the specimens under different doping amounts, and find out the specimen with the largest bending strength as the optimal doping ratio;

[0044] S4. Durability test

[0045] Repeat steps S1 and S2 according to the optimal doping ratio of step S3 to make test blocks. After the test blocks are cured under natural conditions for 28 days, they are immersed in 50°C hot water for curing. The flexural properties of the test blocks cured for different times in 50°C hot water are tested respectively to find out the attenuation law of the flexural properties and obtain the durability performance.

[0046] Example 1 Testing of the Bending Strength of Recycled Fibers in Wind Turbine Blades

[0047] Before use, cure the 42.5 sulphoaluminium cement and river sand in a dry room (temperature 20±2°C, humidity 60%) for 24 hours and set aside. Put 12.8% of the pure propylene polymer emulsion by mass and 1% of the pure propylene polymer emulsion by mass in a stirring pot and mix them evenly. Then, premix 1 part of 42.5 sulphoaluminium cement, 1 part of river sand, 0-0.1 parts of crushed recycled fiber and 1.6‰ of polycarboxylic acid water-reducing agent by mass of the slurry and add them to the mixed liquid. After stirring at a low speed for 2 minutes, add 0.19 parts of water and continue to stir evenly to obtain a mortar adhesive material.

[0048] The obtained adhesive material is subjected to a fluidity test: a metal ring with an inner diameter of 57mm and a height of 55mm is placed in the center of a 500mm*500mm glass plate, and the obtained adhesive material is injected into the metal ring. After it is filled, the metal ring is knocked to remove the internal air, the adhesive material plane on the upper part of the metal ring is smoothed, and the metal ring is lifted to allow the adhesive material to diffuse freely on the glass plate. The diameter of the ring covered by the adhesive material is recorded as the fluidity.

[0049] Pour the mixed adhesive material into the mold, vibrate for 1 minute, smooth the surface, and place it in a standard curing room for 24 hours; the demoulded specimens are placed in a dry air room for 6 hours before the bending strength test is performed. The bending strength test is completed using an electronic universal testing machine. During the test, the test force-axial deformation curve is recorded, and the bending limit load (Pm) is read. The thickness (h) and width (b) of each group of specimens are measured, and the bending strength is calculated using the following formula:

[0050] Then the flexural strength was averaged.

[0051] The fluidity and flexural strength obtained by testing in this embodiment are shown in Table 1.

[0052] Table 1 Bending strength test table

[0053]

[0054] As shown in Table 1, compared with the specimens without recycled fiber, the flexural strength of the specimens with recycled fiber added has increased significantly, and with the increase of the amount of recycled fiber added, the flexural strength gradually increases, especially when the amount added is 0.06-0.1 parts, the flexural strength increases significantly. As the amount of recycled fiber added increases, the fluidity of the material decreases, and when the amount of added exceeds 0.08 parts, the fluidity does not change significantly. Through the test of fluidity and flexural performance, it is determined that the optimal amount of recycled fiber added for wind turbine blades is 0.08 parts.

[0055] The length and diameter of the recycled fibers from the broken wind turbine blades used in this embodiment were tested, wherein the average length of the recycled fibers was tested according to GB / T 14336-2008, and the average diameter was tested according to GB / T 10685-2007. Screens with diameters of 0.5 mm, 1 mm, 2 mm, and 3 mm were used to screen the recycled fibers, and several different segments of less than 0.5 mm, O-0.5 (0.5 mm to 1 mm), A-1 (1 mm to 2 mm), B-2 (2 mm to 3 mm), and C-3 (3 mm) were obtained. The specific major-diameter distribution is shown in Table 2.

[0056] Table 2 Bending strength test table

[0057] Classification Average length (mm) Average diameter (μm) Average aspect ratio Quantity share (%) 0.5mm or less 2.9 195.31 14.8 8.8 O-0.5(0.5mm~1mm) 6.5 317.09 25.1 51.9 A-1(1mm~2mm) 9 385.32 26.6 27.9 B-2(2mm~3mm) 12.5 659.41 22.1 9.3 C-3(3mm) 12.7 873.94 18.3 2.1 Mean 9.3 384.54 29.6 100

[0058] It can be seen that the length and diameter of the recycled fibers from wind turbine blades are relatively dispersed after recycling, and most of them are short fibers. The length and diameter distribution of the recycled fibers from different wind turbine blades after crushing are also different. It is impossible to use the existing national and industry standards to test the performance, and it is impossible to reasonably utilize the recycled fibers according to their specific performance. The testing method of the present invention can effectively test the performance of the recycled fibers, thereby guiding the resource utilization of the recycled fibers.

[0059] Example 2 Durability test of recycled fiber from wind turbine blades

[0060] According to the steps of Example 1, different test blocks were prepared by changing the ratio of the raw materials during the test piece preparation process.

[0061] After curing for 28 days under natural conditions at a temperature not lower than 5°C, each test block was immersed in 50°C hot water for curing. The bending properties were tested after curing for 67 days, 93 days, and 243 days in 50°C hot water, respectively, to find out the attenuation law of the bending properties and obtain the durability performance.

[0062] According to the correspondence between natural aging under temperature and other conditions in each region and accelerated aging under 50°C hot water immersion, after 28 days of natural aging, curing under 50°C hot water immersion for 67 days is equivalent to 30 years of natural aging in the Northeast and Northwest regions; curing under 50°C hot water immersion for 93 days is equivalent to 50 years of natural aging in the Northeast and Northwest regions; curing under 50°C hot water immersion for 243 days is equivalent to 50 years of natural aging in the Beijing-Tianjin-Tangshan region.

[0063] The bending properties obtained under different aging conditions after various raw material ratios are shown in Tables 3 and 4 respectively.

[0064] Table 3 Durability test table of sulphoaluminum cement

[0065]

[0066] Table 4 Durability test table of ordinary silicon cement

[0067]

[0068] From Table 3 and Table 4, it can be seen that the 42.5 sulphoaluminum cement has stronger flexural strength than 42.5 ordinary silicate cement, and the material has better durability. However, after curing in 50℃ hot water for 243 days, the flexural strength of sulphoaluminum cement still has a large downward trend, while the flexural strength of ordinary silicate cement tends to be stable. Sulphoaluminum cement can be considered when used in material industries with high durability requirements, and ordinary silicate cement can be selected in material industries with low durability requirements and full consideration of cost.

[0069] From the durability time point of view, after curing under 50°C hot water immersion for 93 days, the flexural strength of the test block using sulphoaluminum cement did not decrease significantly, while the flexural strength of the test block using ordinary silicate cement decreased significantly. Therefore, if the material is used in the northwest and northeast regions, sulphoaluminum cement can be used; if the material is used in the Beijing-Tianjin-Tangshan region, sulphoaluminum cement or ordinary silicate cement can be selected according to cost requirements; if the material is used in East China, South China and other places, the curing time under 50°C hot water immersion can be adjusted according to the test method of the present invention, and the durability of the recycled fiber can be tested to determine whether it can be used.

[0070] Therefore, through the performance testing method of the wind turbine blade recycled fiber of the present invention, the flexural strength and durability of the recycled fiber can be tested before the recycled fiber is used, so as to determine the scope and applicable area of ​​the recycled fiber. In actual use, the proportion of the test piece can be adjusted according to actual needs. For example, in addition to sulphoaluminum cement and general silica cement, gypsum, lime, etc. can also be used; water reducer, polymer, defoamer can be selected according to actual needs, and are not limited to the present invention.

[0071] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0072] The embodiments of the present invention are described above, but the present invention is not limited to the above-mentioned specific implementation modes. The above-mentioned specific implementation modes are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which are all within the protection of the present invention.

Claims

1. A performance testing method for recycled fibers of wind turbine blades, characterized in that: The following steps are involved: S1. Preparation of adhesive materials The pure acrylic polymer emulsion and the defoamer are mixed and stirred evenly, and then cement, river sand, crushed recycled fiber, and polycarboxylate water reducer are pre-mixed and added to the mixed liquid, and water is added and stirred evenly to obtain a mortar adhesive material; S2. Bending performance test Pour the evenly stirred adhesive material into the mold, vibrate for 1 minute, smooth the surface, and place it in a standard curing room for 24 hours; the demoulded specimen is then placed in a dry air room for curing for 6 hours, and then the bending strength of the specimen is tested; S3. Determine the optimal doping ratio of recycled fibers Adjust the fiber doping amount in step S1, and repeat step S2 to detect the bending strength of the specimens under different doping amounts, and find out the specimen with the largest bending strength as the optimal doping ratio; S4. Durability test Repeat steps S1 and S2 according to the optimal doping ratio of step S3 to make test blocks. After the test blocks are cured under natural conditions for 28 days, they are immersed in 50°C hot water for curing. The flexural properties of the test blocks cured for different times in 50°C hot water are tested respectively to find out the attenuation law of the flexural properties and obtain the durability performance.

2. A method for testing the performance of recycled fibers for wind turbine blades as claimed in claim 1, characterized in that: The cement is selected from 42.5 sulphoaluminium cement or 42.5 silicate cement.

3. A method for testing the performance of recycled fibers for wind turbine blades as claimed in claim 1, characterized in that: In step S1, pure acrylic polymer emulsion and defoamer are put into a stirring pot and mixed and stirred evenly, then cement, river sand, crushed recycled fiber, and polycarboxylic acid water reducer are premixed and added to the mixed liquid, stirred at a low speed for 2 minutes, and then water is added and stirred evenly to obtain a mortar adhesive material.

4. A method for testing the performance of recycled fibers for wind turbine blades as claimed in claim 1, characterized in that: The addition amount of the water reducing agent is 1.6‰ of the total mass of the mortar, and the addition amount of the defoaming agent is 1% of the mass of the polymer.

5. A method for testing the performance of recycled fibers for wind turbine blades as claimed in claim 1, characterized in that: The added amount of the recycled fiber is 1-14% of the cement mass.

6. A method for testing the performance of recycled fibers for wind turbine blades as claimed in claim 1, characterized in that: The cement and river sand are cured in a dry room for 24 hours before use.

7. A method for testing the performance of recycled fibers for wind turbine blades as claimed in claim 1, characterized in that: The bending strength test was completed using an electronic universal testing machine. During the test, the test force-axial deformation curve was recorded, the bending limit load (Pm) was read, the thickness (h) and width (b) of each group of specimens were measured, and the bending strength was calculated using the following formula: Then the flexural strength was averaged.

8. A method for testing the performance of recycled fibers for wind turbine blades as claimed in claim 1, characterized in that: In the durability test of step S4, the bending resistance after curing in 50°C hot water for 28d, 67d, 93d and 243d is selected respectively.

9. Application of the performance testing method for recycled fiber of wind turbine blades according to any one of claims 1 to 8 in the selection of application fields and application areas of recycled fiber.

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