A test method for the adhesion strength of a flat catalyst

Abstract

The present invention relates to a method for testing the adhesion strength of a flat catalyst, comprising the following steps: S1, prepare a loading box with a top opening, a sample loader, a counterweight, and a flat catalyst; S2, weigh the flat catalyst and record the first weight; S3, place the flat catalyst in the sample loader, and then place the sample loader at the bottom of the loading box; S4, fill the loading box with simulated sand and cover the sample loader, and then press the counterweight on the simulated sand; S5, move the sample loader from the bottom to the outside of the loading box, then separate the catalyst from the sample loader, weigh it after purging the simulated sand, and record the second weight. The adhesion strength λ of the flat catalyst is obtained through a formula. In the test of the adhesion strength of the flat catalyst coating in the present invention, it is not necessary to bend the catalyst, and the shedding of active substances under real operating conditions can be simulated; the test data can be reproduced; it will not harm human health and will not cause environmental pollution.

Description

Technical Field

[0001] The present invention belongs to the field of testing the adhesion strength of flat catalysts, and particularly relates to a method for testing the adhesion strength of flat catalysts. Background Art

[0002] Catalysts are the core of the denitration devices in thermal power plants. Flat SCR catalysts are formed by calcining after coating active substances such as vanadium and titanium dioxide on them. Because of its many advantages, it has been widely used. Among them, the most important advantage is that the active substances on the surface of the flat catalyst are blown off during use, but due to the existence of the substrate, no collapse will occur, preventing the formation of a passage for flue gas and ensuring the safe operation of the unit.

[0003] Therefore, the industry standard DLT - 1286 defines the adhesion strength of flat catalysts: when the flat catalyst is subjected to bending pressure or dust - laden gas flow scouring, the ability of the coating composed of active substances, etc. to adhere to the substrate, expressed in %. The detection method is specified: the specimen is vertically fixed on a column - axis bending tester, the sample is bent smoothly and quickly, after the test is completed, the specimen is taken down, and compressed air with a pressure of 0.1 MPa is used to blow back and forth evenly at the bent part of the specimen for 20 s, and then weighed and recorded.

[0004] This method has the following disadvantages: (1) The bending process causes the shedding of active substances, and it is impossible to simulate the shedding of active substances in the actual operating conditions of flat catalysts. (2) The shedding of active substances caused by bending is relatively random, and it is difficult for different testing units to reproduce the test data. (3) During the test, compressed air is required to blow the bent part, and the catalyst dust at the bent part will be blown up and float in the air, endangering human health and causing environmental pollution. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for testing the adhesion strength of flat catalysts, so as to solve the problems that the existing testing methods for the adhesion strength of flat catalysts are difficult to reproduce test data, and the catalyst dust will endanger human health and cause environmental pollution.

[0006] To achieve the above - mentioned purpose, the technical solution adopted by the present invention is:

[0007] A method for testing the adhesion strength of flat catalysts, which comprises the following steps:

[0008] S1. Prepare a loading box with a top opening, a sample loader, a counterweight, and a flat catalyst;

[0009] S2. Weigh the flat catalyst and record it as the first weight W1;

[0010] S3. Place the weighed plate catalyst in the sample loader, and then place the sample loader at the bottom of the loading box. Here, the sample loader fixes the edge of the plate catalyst, and the middle part of the catalyst is exposed inside the loading box;

[0011] S4. Fill the loading box with simulated sand to cover the sample loader, and then press a weight on the simulated sand;

[0012] S5. Move the sample loader from the bottom to the top out of the loading box, then detach the plate catalyst from the sample loader, blow the simulated sand on the catalyst and weigh it, record it as the second weight W2, and the adhesion strength λ of the plate catalyst is obtained by the following formula:

[0013]

[0014] wherein, W1 is the total weight of all plate catalysts before testing, W2 is the total weight of all plate catalysts after testing, and N is the number of catalysts.

[0015] Preferably, in step S1, the loading box has a bottom surface and an annular side surface perpendicular to the bottom surface. The annular side surface is connected to the bottom surface and encloses a receiving space with a top opening.

[0016] Preferably, in step S3, the surface where the plate catalyst is located is perpendicular to the bottom surface of the loading box.

[0017] Preferably, in step S1, the sample loader fixes one or more plate catalysts. The sample loader includes one or more connected annular frames. The annular frames are enclosed on all sides and have a through middle part. The annular frames are provided with installation grooves for fixing the plate catalysts, and the plate catalysts are fixed in the installation grooves of the annular frames.

[0018] Preferably, the annular frame is square. When there are multiple annular frames, the multiple annular frames are connected into one body through one of their sides, and the included angle between two adjacent annular frames is greater than 0° and less than or equal to 180°.

[0019] Preferably, in step S4, the simulated sand is selected from quartz sand or steel sand. From the bottom to the top of the loading box, the simulated sand is laid in multiple layers, and the particle sizes of each layer of simulated sand are different.

[0020] Preferably, the particle sizes of the multiple layers of simulated sand increase layer by layer from bottom to top.

[0021] Preferably, in step S4, the height or volume of each layer of simulated sand laid in the loading box is the same.

[0022] Preferably, in step S5, the sample loader is evenly moved out of the loading box by the lifting mechanism. The lifting mechanism includes a lifting member and a driving member. One end of the lifting member is connected to the driving member, and the other end of the lifting member is used to connect to the sample loader. The driving member is used to drive the lifting member to move along the height direction of the receiving space of the loading box.

[0023] Preferably, in step S5, during the process of moving the sample loader from the bottom to the top out of the loading box, the counterweight always presses down on the simulated sand.

[0024] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: In the test of the adhesion strength of the flat catalyst coating of the present invention, there is no need to bend the catalyst, avoiding the situation of the active substance falling off caused by bending the catalyst in the original test method, and it can simulate the situation of the active substance falling off of the flat catalyst under the actual operating conditions; the test data can be reproduced; during the test process, the catalyst dust will not be blown up and float in the air, will not harm human health, and will not cause environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG Figure 1 is a schematic structural view of the loading box and the sample loader of the present invention in the test state;

[0026] FIG Figure 2 is a bottom view of the loading box of the present invention;

[0027] FIG Figure 3 is a side view of the loading box of the present invention;

[0028] FIG Figure 4 is a schematic structural view of the four annular frames of the present invention;

[0029] FIG Figure 5 is a top view of the four annular frames of the present invention;

[0030] FIG Figure 6 is a side view of the two annular frames of the present invention;

[0031] FIG Figure 7 is a schematic structural view of a single annular frame of the present invention;

[0032] FIG Figure 8 is a schematic structural view of the four receiving boxes of the present invention;

[0033] FIG Figure 9 is a top view of the four receiving boxes of the present invention.

[0034] In the above drawings:

[0035] 1 - Loading box, 2 - Ring-shaped frame, 21 - Insertion opening, 3 - Accommodating box, 4 - Positioning part, 5 - Lifting part. Detailed implementation mode

[0036] The present invention will be further described below in conjunction with the embodiments shown in the accompanying drawings.

[0037] The steps of a flat catalyst adhesion strength test method are as follows:

[0038] S1. Prepare a loading box 1 with a top opening, a sample loader, a counterweight, and a flat catalyst;

[0039] When preparing the flat catalyst, cut a sample with a preset size evenly from different positions of the flat catalyst. If multiple samples are cut, the sizes of the multiple samples are the same. Cut the straight part of the flat catalyst, that is, the sample does not include the corrugated part of the flat catalyst. After marking and numbering the samples, dry them. The flat catalyst is easy to absorb water, and heat is used to drain the water inside the flat catalyst. Drying conditions: Place it in a constant temperature oven at 105 ± 2 °C for 2 h, take it out and cool it naturally to room temperature.

[0040] The structure of the loading box 1 is as follows: Refer to Figure 1 , Figure 2 , Figure 3 , it has a bottom surface and a ring-shaped side surface perpendicular to the bottom surface. The ring-shaped side surface is connected to the bottom surface and encloses to form a storage space with a top opening. For example, the loading box 1 is in the shape of a cube or a cylinder. The bottom surface of the loading box 1 is a trapezoidal platform, and the trapezoidal platform is fixed on the horizontal plane.

[0041] The structure of the sample loader is as follows: Refer to Figure 4 , Figure 5 , Figure 6 , Figure 7 , the sample loader is used to fix one or more flat catalysts. The sample loader includes one or more connected ring-shaped frames 2. The ring-shaped frames 2 enclose on all sides and are penetrated in the middle. The ring-shaped frames 2 are provided with installation grooves for fixing the flat catalysts. In the test state, the sample loader is located in the storage space of the loading box 1. The surface where the ring-shaped frame 2 is located is perpendicular to the bottom surface of the loading box 1, that is, the sample is perpendicular to the bottom surface of the loading box 1. The installation grooves fix the edges of the flat catalysts and can form a coating around the flat catalysts. Other parts (such as the middle part) of the flat catalysts except the edges are exposed in the loading box 1.

[0042] An insertion opening 21 communicating with the installation groove is provided on the ring-shaped frame 2. The flat catalyst is inserted into the installation groove through the insertion opening 21, which facilitates inserting the flat catalyst into the installation groove.

[0043] It is optimal that the annular frame 2 is square. When there are multiple annular frames 2, the multiple annular frames 2 are connected into one body through one of their sides, and the included angle between two adjacent annular frames 2 is greater than 0° and less than or equal to 180°. For example, when four annular frames 2 are set, when the four annular frames 2 are projected on the same horizontal plane, they are in an X shape or a cross shape (the included angle between two adjacent annular frames 2 is 90°); when two annular frames 2 are set, the included angle between the two annular frames 2 is 180°; when three annular frames 2 are set, the included angle between two adjacent annular frames 2 is 120°.

[0044] If the annular frame 2 is square, an installation groove is arranged at the bottom edge of the annular frame 2, and insertion openings 21 communicating with the installation groove can be arranged on the other three sides of the annular frame 2; or installation grooves are arranged at the bottom edge and one side adjacent to the bottom edge of the annular frame 2, and insertion openings 21 communicating with the installation groove can be arranged on the other two sides; or installation grooves are arranged at the bottom edge and the side opposite to the bottom edge of the annular frame 2, and insertion openings 21 communicating with the installation groove can be arranged on the other two sides; or installation grooves are arranged at the bottom edge and two of the sides of the annular frame 2, and an insertion opening 21 communicating with the installation groove can be arranged on the other side.

[0045] A pointed top is arranged at the top of the annular frame 2, such as Figure 7 the top cross-section in [reference] is triangular, that is, one end of the top of the annular frame 2 close to the bottom gradually narrows towards the other end away from its bottom, which is convenient for lifting the sample loader out of the loading box 1 upwards.

[0046] A positioning part 4 is arranged on the bottom surface of the loading box 1. The positioning part 4 is used to position the annular frame 2 to prevent it from moving on the bottom surface of the loading box 1, but the annular frame 2 can move up and down in the loading box 1. For example, the positioning part 4 is a positioning groove opened on the bottom surface of the loading box 1, which is convenient for fixing the annular frame 2.

[0047] S2. Weigh the flat catalyst and record it as the first weight W1;

[0048] S3. Place the weighed flat catalyst in the sample loader, and then place the sample loader at the bottom of the loading box 1. Among them, the sample loader fixes the edge of the flat catalyst, and the middle part of the catalyst is exposed in the loading box 1; it is optimal that the surface where the flat catalyst is located is perpendicular to the bottom surface of the loading box 1, which increases the contact area between the flat catalyst and the simulated sand and is more in line with the actual environment.

[0049] S4. Fill the simulated sand in the loading box 1 and cover the sample loader, and then press the counterweight on the simulated sand;

[0050] The simulated sand is selected from quartz sand or steel sand. The simulated sand is used to simulate dust in the air, which is equivalent to magnifying the dust.

[0051] From the bottom to the top of the loading box 1, multiple layers of simulated sand are laid, and the particle sizes of the simulated sand in each layer are different. When the sample loader is moved upward from the bottom of the loading box 1 out of the loading box 1, the flat catalyst on the sample loader contacts each layer of simulated sand. The flat catalyst can contact each layer of simulated sand with different particle sizes, which is equivalent to fully contacting dust of different sizes in the air, and can better simulate the contact with dust of different sizes in the actual environment, that is, it is closer to the actual environment.

[0052] During the contact between the flat catalyst and the simulated sand, the catalyst dust that falls off will remain in the simulated sand in the loading box 1 and will not be blown up and float in the air. This device will not endanger human health or cause environmental pollution during measurement.

[0053] The particle sizes of the multiple layers of simulated sand increase layer by layer from bottom to top. The layer of simulated sand with a larger particle size is located above the layer of simulated sand with a smaller particle size, preventing the mixing of the small-particle-size simulated sand and the large-particle-size simulated sand during the process of the sample loader moving from the bottom to the top, which may cause the mixing of the multiple layers of simulated sand and result in the flat catalyst being unable to contact each layer of simulated sand with different particle sizes.

[0054] The height or volume of each layer of simulated sand laid in the loading box 1 is the same. When the height of each layer of simulated sand laid in the loading box 1 is the same, precise operation can be carried out by referring to the scale line on the annular side of the loading box 1 during addition; when the volume of each layer of simulated sand laid in the loading box 1 is the same, the height of the layer of simulated sand at the bottom of the loading box 1 is higher (a sample loader is placed at the bottom of the loading box 1, and the sample loader occupies a certain space), and the heights of the other layers are the same.

[0055] Scale lines are provided on the annular side of the loading box 1 (the scale lines are set inside or outside the annular side, and the annular side can be transparent). The scale lines are used to mark the volume or height of the simulated sand filled in the storage space of the loading box 1. When multiple layers of simulated sand are laid, it is optimal that the height (or volume) of each layer of simulated sand is the same. When putting in each layer of simulated sand, just look at the scale line on the annular side of the loading box 1, and stop putting in the simulated sand when reaching the required scale line. Through the scale line, the height of each layer of simulated sand can be precisely controlled, which is simple, fast, and has high precision.

[0056] The multiple layers of simulated sand are filled from bottom to top in sequence, and the filling height of each layer is the same, such as 200 mm, which is consistent with the size scale on the quartz sand loading box 1. Keep the test sand in a free state during filling, and no artificial pressure should be applied. After the last layer is filled to the marked line, press the weight plate onto the simulated sand. The weight is located at the top of the loading box 1, leaving a middle gap to facilitate pulling the sample loader out of the loading box 1.

[0057] The structure of the weight is as follows: it includes a containing box 3 and weight-increasing blocks. See Figure 8 and Figure 9, the weight increasing block is arranged in the accommodating box 3. The accommodating box 3 has a bottom surface and an annular side surface perpendicular to the bottom surface. The annular side surface is connected to the bottom surface and encloses a storage space with a top opening. One weight increasing block is placed in the storage space of each accommodating box 3. The weight increasing block is preferably a weight, and each weight weighs 1 kg. The weight of the weight is selected according to the sample size, and the weight of each weight is not limited to 1 kg. A counterweight is provided to prevent the sample loader from being moved upward from the bottom of the loading box 1, simulating the movement of sand, which affects the test results.

[0058] When the accommodating box 3 is pressed down on the simulated sand, a gap is maintained between two adjacent accommodating boxes 3 (as indicated by a in Figure 9 ), and this gap allows the annular frame 2 to pass through and move out of the loading box 1. When four accommodating cavities and four annular frames 2 are provided, the gaps between the four accommodating cavities are in an X shape or a cross shape, and the four annular frames 2 are in an X shape or a cross shape on the same projection plane. The four annular frames 2 can pass through the gaps between the four accommodating cavities during movement, while the counterweight always presses on the simulated sand and does not move out of the loading box 1.

[0059] Alternatively, through holes are provided in the accommodating box 3. When the sample loader is lifted, the lifting member 5 and the sample loader can both pass through the through holes of the accommodating box 3, and the counterweight always presses down on the simulated sand and does not move out of the loading box 1.

[0060] S5. Move the sample loader from the bottom to the top and out of the loading box 1, then separate the flat catalyst from the sample loader, blow the simulated sand on the catalyst and weigh it, record it as the second weight W2. The adhesion strength λ of the flat catalyst is obtained through the following formula:

[0061]

[0062] Among them, W1 is the total weight of all flat catalysts before testing, W2 is the total weight of all flat catalysts after testing, and N is the number of catalysts.

[0063] In step S5, during the process of moving the sample loader from the bottom to the top and out of the loading box 1, the counterweight always presses down on the simulated sand to prevent the simulated sand from moving.

[0064] The sample loader is moved out of the loading box 1 at a constant speed through a lifting mechanism. The lifting mechanism includes a lifting member 5 and a driving member. One end of the lifting member 5 is connected to the driving member, and the other end of the lifting member 5 is used to connect to the sample loader. The driving member is used to drive the lifting member 5 to move along the height direction of the storage space of the loading box 1. During the lifting process, the lifting mechanism moves the sample loader out of the loading box 1 at a constant speed, which can ensure that the flat catalyst contacts each layer of simulated sand for the same time.

[0065] The structure of the lifting mechanism is as follows: It includes a lifting member 5 and a driving member. One end of the lifting member 5 is connected to the driving member. In the test state, the other end of the lifting member 5 is connected to the sample loader (see Figure 1 ), and the driving member is used to drive the lifting member 5 to move along the height direction of the storage space of the loading box 1, that is, to move the sample loader upward from the bottom of the loading box 1 to outside the loading box 1 through the lifting mechanism. In the non-test state, the lifting member 5 of the lifting mechanism is located outside the loading box 1. The lifting member 5 is a suspension rope or a metal chain, and the driving member is a motor.

[0066] In step S3, after placing the sample loader at the bottom of the loading box 1, connect the other end of the lifting member 5 to the sample loader. Then proceed to step S4.

[0067] Embodiment

[0068] S1. Prepare a loading box 1 with an open top, a sample loader, a counterweight, and a flat catalyst;

[0069] Among them, take a flat catalyst from a certain factory, and evenly cut 4 specimens with a size of about 100 mm×60 mm from different positions of the flat catalyst. The specimens do not include the corrugated part of the catalyst. Mark and number each sample and place it in a constant temperature oven at 105±2 °C for drying for 2 h, then take it out and naturally cool it to room temperature.

[0070] The upper part of the loading box is a cuboid with a cross-section of 120×120 mm and a length of 1100 mm, and there are obvious scale line marks every 200 mm on the annular side.

[0071] S2. Weigh the flat catalyst and record it as w a1 , w a2 , w a3 , w a4 , w a1 = 9.3147 g, w a2 = 9.5784 g, w a3 = 9.1129 g, w a4 = 8.9275 g;

[0072] S3. Place the weighed flat catalyst in the sample loader, and then place the sample loader at the bottom of the loading box 1. Among them, the sample loader fixes the edge of the flat catalyst, and the middle part of the catalyst is exposed inside the loading box 1;

[0073] Load the samples into the sample loader from the side loading port respectively. After loading, keep about 10 mm of the edge of a single sample surrounded and fixed by the installation groove of the annular frame 2 of the sample loader, that is, the actual measurable area of the sample is 90 mm×50 mm. After loading the samples, place the sample loader at the bottom of the loading box 1 for positioning.

[0074] Connect the lifting rope of the lifting mechanism to the annular frame 2 of the sample loader, and ensure that the lifting rope is in a vertical state.

[0075] S4. Fill the loading box 1 with five layers of simulated sand in sequence and cover the sample loader. Each layer is filled with 200 mm. Then, press 4 weights (each weighing 1 kg) on the simulated sand, leaving a middle gap for the lifting member 5 to lift the sample loader.

[0076] If five layers of simulated sand are set, from the bottom of the loading box 1 upwards, they are successively divided into the first layer, the second layer, the third layer, the fourth layer, and the fifth layer. The particle sizes of the five layers of simulated sand are as follows:

[0077] Table 1 Particle size gradient table of five layers of simulated sand

[0078] Level The first layer The second layer The third layer The fourth layer The fifth layer Particle size 10 - 20 mesh 20 - 30 mesh 30 - 40 mesh 40 - 50 mesh 50 - 60 mesh

[0079] S5. Start the drive motor to make the lifting rope rise at a uniform speed. The speed is set to 0.1 m / s until the sample loader is completely detached from the loading box 1. Then, take out the sample from the loader, blow the quartz sand attached to the sample piece, and weigh it as w b1 , w b2 , w b3 , w b4 , w b1 = 9.1053 g, w b2 = 9.3625 g, w b3 = 9.0178 g, w b4 = 8.7236 g.

[0080] The adhesion strength λ of the flat catalyst is obtained by the following formula:

[0081]

[0082] where λ is in units of 100%, wa1, wa2, wa3, wa4 represent the mass of the specimen before testing, in units of g; wb1, wb2, wb3, wb4 represent the mass of the specimen after testing, in units of g.

[0083] The calculated adhesion strength

[0084] The adhesion strength of this flat catalyst is 0.18%.

[0085] In the test of the adhesion strength of the flat catalyst coating, there is no need to bend the catalyst, avoiding the situation of the active substance falling off caused by bending the catalyst in the original test method, and it can simulate the situation of the active substance falling off of the flat catalyst under real operating conditions; the test data can be reproduced; during the test, the catalyst dust will not be blown up and float in the air, will not harm human health, and will not cause environmental pollution.

[0086] The above embodiments are only for illustrating the technical concept and characteristics of the present invention, and the purpose is to enable those who are familiar with this technology to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for testing the adhesion strength of a flat catalyst, characterized in that: It includes the following steps: S1. Prepare a loading box with a top opening, a sample loader, a counterweight, and a flat catalyst; S2. Weigh the flat catalyst and record it as the first weight W1; S3. Place the weighed flat catalyst in the sample loader, and then place the sample loader at the bottom of the loading box. Among them, the sample loader fixes the edge of the flat catalyst, and the middle part of the catalyst is exposed in the loading box; the surface where the flat catalyst is located is perpendicular to the bottom surface of the loading box; S4. Fill the loading box with simulated sand and cover the sample loader, and then press the counterweight on the simulated sand; the simulated sand is selected from quartz sand or steel sand. From the bottom to the top of the loading box, the simulated sand is laid in multiple layers, and the particle sizes of each layer of simulated sand are different; S5. Move the sample loader from the bottom to the outside of the loading box, then separate the flat catalyst from the sample loader, blow the simulated sand on the catalyst and then weigh it, record it as the second weight W2, and the adhesion strength λ of the flat catalyst is obtained by the following formula: Where W1 is the total weight of all flat catalysts before testing, W2 is the total weight of all flat catalysts after testing, and N is the number of catalysts.

2. The method for testing the adhesion strength of a flat catalyst according to claim 1, characterized in that: In step S1, the loading box has a bottom surface and an annular side surface perpendicular to the bottom surface. The annular side surface is connected to the bottom surface and encloses a receiving space with a top opening.

3. The method for testing the adhesion strength of a flat catalyst according to claim 1, characterized in that: In step S1, the sample loader fixes one or more flat catalysts. The sample loader includes one or more connected annular frames. The annular frames are enclosed on all sides and penetrate in the middle. The annular frames are provided with installation grooves for fixing the flat catalysts, and the flat catalysts are fixed in the installation grooves of the annular frames.

4. The method for testing the adhesion strength of a flat catalyst according to claim 3, characterized in that: The annular frame is square. When there are multiple annular frames, the multiple annular frames are connected into one body through one of their sides, and the included angle between adjacent two annular frames is greater than 0° and less than or equal to 180°.

5. The method for testing the adhesion strength of a flat catalyst according to claim 1, characterized in that: The particle sizes of the multiple layers of simulated sand increase layer by layer from bottom to top.

6. The method for testing the adhesion strength of a flat catalyst according to claim 1, characterized in that: In step S4, the height or volume of each layer of simulated sand laid in the loading box is the same.

7. The method for testing the adhesion strength of a flat catalyst according to claim 1, characterized in that: In step S5, the sample loader is evenly moved out of the loading box by the lifting mechanism. The lifting mechanism includes a lifting member and a driving member. One end of the lifting member is connected to the driving member, and the other end of the lifting member is used to connect to the sample loader. The driving member is used to drive the lifting member to move along the height direction of the receiving space of the loading box.

8. According to the flat catalyst adhesion strength test method described in claim 1, characterized in that: In step S5, during the process of moving the sample loader from the bottom to the top out of the loading box, the counterweight always presses down on the simulated sand.

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